JP2012504093A - Zirconium hydrate powder - Google Patents

Abstract

The present invention has a maximum particle size D _99.5 of less than 200 μm and a porosity index Ip greater than 2, which is equal to the ratio A _sr / A _sg , where A _sg is the theoretical value of the powder particles Geometric specific surface area, A _sr relates to powder which is a measurement of actual specific surface area by BET method. More than 20% of the powder is agglomerated or non-agglomerated, all having dimensions greater than 200 nm, a sphericity index of less than 0.6, from zirconium oxide of formula MO _x and / or hafnium Formed from the base particles. More than 20% of the powder is agglomerated or not agglomerated, having a sphericity index of less than 0.6, of the formula MO _x (OH) _y (OH ₂ ) _z , doped or doped Not formed from base particles consisting of zirconium hydrate and / or hafnium, or a mixture of such hydrates. The present invention can be applied to catalysis and filtration.

Description

  The invention relates to a process for the production of powders which are intended in particular to catalyze chemical reactions or to be filtered. The invention also relates to a powder produced or that can be produced by such a method. More generally, the present invention relates to zirconium and / or hafnium derivative powders, zirconium and / or hafnium hydrate powders, and zirconium and / or hafnium oxide powders. Finally, the invention relates to the use of the powder according to the invention in certain applications, in particular in catalysis and filtration.

  Catalysts are involved in many reactions in various technical fields, especially in environmental applications, petrochemistry or fine chemistry. The catalyst is to change the rate of the chemical reaction by placing the reagent of this reaction in contact with a catalyst that does not appear in the reaction balance, such as platinum. In general, the catalyst is pre-deposited on the support, for example in the form of a powder or a substance formed from such a powder. The powder sometimes can itself act as a catalyst.

  Fluid filtration also pertains to many applications, particularly liquid or gas filtration at high temperatures. For this reason, the fluid is a powder or a substance formed from a powder so that the object to be filtered is held in its form in the interstices between the particles or in the pores of these particles. Pass through.

  In catalytic applications, the particles, whether used as a catalyst support or as the catalyst itself, must have a maximum specific surface area to increase the contact surface between the catalyst and the reagent.

  In filtration applications, it is desirable that pressure loss be minimal during the passage of the fluid to be filtered.

  In these applications, the particles can be subject to high temperature or severe thermomechanical constraints.

  The particles and their method of manufacture are disclosed in particular in the following documents:

  FR2662434 relates to the production of monoclinic zirconia trikite via hydrothermal synthesis. These trichites are of micrometer size (about 5 μm in the cited example) and are dense as a result of hydrothermal treatment temperatures between 300 ° C. and 700 ° C.

EP 0207469 relates to the production of crystals of zirconia, sulfate-doped zirconia, or optionally sulfate-doped zirconium hydrate, which are in a layered form with a thickness of less than 50 nm. These crystals are produced by heating an acidic aqueous solution (pH <2) of soluble zirconium salt and sulfate between 110 ° C. and 350 ° C. to form zirconium oxysulfate hydrate (formula Zr ₅ O ₈ (SO ₄ ) ₂ · nH ₂ O) followed by calcination at a temperature higher than 600 ° C. or desulfating at a temperature between 70 and 110 ° C.

  EP0233343 is an ultrafine monoclinic crystal in the form of a single fiber with a diameter of less than 5 nm, agglomerated in the form of a “pile” with a width between 30 and 200 nm and a length between 200 nm and 1 μm It relates to the production of zirconia particles.

  The paper `` Zirconia needles synthesized inside hexagonal swollen liquid crystals ''-Chemistry Of Materials, 2004, 16, pp. 4187-4192, is a millimeter or even centimeter-sized needle with 20 nm pores formed from smaller needles. Describes the generation of.

The article `` Products of thermal hydrolysis in Zr (SO ₄ ) ₂ -Zr (OH) ₄ -H ₂ O system ''-Journal of the ceramic society of Japan, Vol. 102, No. 9, pp. 843-846 relates to the production of zirconia. . The production method described in this article includes the step of precipitating an acidic aqueous solution of zirconium salt and sulfate (H ⁺ ion concentration is 0.4 mol / L) in the presence of Zr (OH) ₄ particles. The present inventors consider that these Zr (OH) ₄ particles are isotropic. The reaction product is then hydrothermally treated at 160-240 ° C., thereby producing a powder of zirconia particles that we consider to be dense.

EP0194191 relates to the production of fine stabilized zirconia powder. This production method uses a zirconia hydrate sol formed from acicular ZrO ₂ elemental crystallites having a size between 1 and 50 nm. According to the present inventors, isotropic stabilized zirconia particles are obtained by sintering at 1300 ° C. after firing at a temperature between 700 ° C. and 1300 ° C.

  The paper `` Highly Ordered Porous Zirconias from Surfactant Controlled Syntheses: Zirconium Oxide-Sulfate and Zirconium Oxo Phosphate ''-Chemistry Of Materials, 1999, 11, 227-234, describes the production of zirconia and sulfate powders. . The method for producing the powder includes the step of precipitating by heating the acidic aqueous solution at 100 ° C. for 48 hours. Such heating conditions, according to the inventors, result in an isotropic morphology of the precipitate particles. Next, the obtained precipitate is calcined at 500 ° C. for 5 hours.

FR2662434 EP0207469 EP0233343 EP0194191

`` Zirconia needles synthesized inside hexagonal swollen liquid crystals ''-Chemistry Of Materials, 2004, 16, pp. 4187-4192 `` Products of thermal hydrolysis in Zr (SO4) 2-Zr (OH) 4-H2O system ''-Journal of the ceramic society of Japan, Vol. 102, No. 9, pp. 843-846 `` Highly Ordered Porous Zirconias from Surfactant Controlled Syntheses: Zirconium Oxide-Sulfate and Zirconium Oxo Phosphate ''-Chemistry Of Materials, 1999, 11, 227-234 `` Preparation of Mesoporous Ce0.5Zr0.5O2 Mixed Oxide by Hydrothermal Templating Method '', Journal of Rare Earths 25, 2007, 710-714 the International Union of Pure and Applied Chemistry, 1994, 66, 8, 1739-1758 Journal of the American Chemical Society 60 (1938) 309-316 E.P.Barrett, L.G.Joyner, P.H.Halenda, J.Am.Chem.Soc., 73 (1951) 373 The Nouveau Traite de Chimie Minerale from Paul Pascal, volume IX, 599-610 `` Morphology of zirconia synthesized hydrothermally from zirconium oxychloride '', Journal of the American Ceramic Society, 1992, 75, 9, 2515-2519 `` Nucleation and growth for synthesis of nanometric zirconia particles by forced hydrolysis '', Journal of Colloid and Interface Science, 1998, 198, 87-99

  There is a continuing need for new particles with high specific surface areas and / or new shapes.

  There is also a need for particles that can withstand high thermal constraints, such as those encountered during gas combustion at high temperatures.

  One object of the present invention is to at least partially satisfy one or more of these required matters.

(Method)
According to a first main embodiment, the present invention comprises the following sequential steps:
a) preparing an acidic mother liquor by mixing at least the following or by mixing only the following:
[1] polar solvent;
[2] a first reagent that provides Zr ⁴⁺ and / or Hf ⁴⁺ ions, preferably soluble in an acidic medium in the solvent;
[3] a second reagent providing an anionic group;
[4] anionic surfactants; amphoteric surfactants; cationic surfactants, carboxylic acids and salts thereof; formulas RCO ₂ R ′ and R-CONHR ′ [where R and R ′ are aliphatic, aromatic A non-ionic surfactant selected from the group of compounds that are aromatic and / or alkylaromatic carbon-based chains, and mixtures thereof; and additives selected from the group formed by mixtures thereof ;
[5] Optionally, another nonionic surfactant;
[6] Optionally, a pore forming agent;
b) heating the mother liquor to precipitate Zr ⁴⁺ and / or Hf ⁴⁺ ions and anionic groups in the form of primary zirconium and / or hafnium derivatives and optionally drying;
c) optionally converting the primary derivative to a secondary zirconium and / or hafnium derivative by substituting the anionic group with another anionic group known as an anionic substituent. Optional drying step;
d) optionally performing a basic hydrolysis of said primary or secondary derivative;
e) optionally firing the primary derivative obtained at the end of step b), the secondary derivative obtained at the end of step c) or the hydrate obtained at the end of step d) (step A method for producing a powder of particles is proposed, which comprises the steps of e ₁ )) or hydrothermal treatment (step e ₂ )) to obtain an oxide of zirconium and / or hafnium and optionally drying.

  As can be seen from the remaining further details of this description, the inventors have discovered that the addition of additives produces particles having advantageous morphology or properties, simply and efficiently. An optional step can convert these particles into other particles that are also useful.

  Steps a) and b), or c) are selected from doped or undoped zirconium and / or hafnium derivatives, preferably doped or undoped zirconium sulfate and / or hafnium derivatives, doped Or selected from undoped zirconium phosphate and / or hafnium derivatives, doped or undoped zirconium carbonate and / or hafnium derivatives, preferably doped or undoped zirconium basic sulfate and / or A material selected from hafnium sulfate, doped or undoped zirconium basic phosphate and / or hafnium phosphate, and doped or undoped zirconium basic carbonate and / or hafnium carbonate, And a mixture of such particles Makes it possible to produce anisotropic porous or dense particles.

  Step d) allows the production of anisotropic and porous particles made of materials selected from doped or undoped zirconium and / or hafnium hydrates. Such anisotropic porous particles are not known to the inventors.

  In one embodiment, to produce a zirconium and / or hafnium oxide powder, the method comprises at most steps a) to e) to produce a zirconium and / or hafnium hydrate powder. The method comprises at most steps a) to d), and in order to produce a zirconium and / or hafnium derivative powder, the method comprises at most steps a) to c).

  In one embodiment, the method does not include a gelling step.

In certain embodiments of the invention, the method may have one or more of the following features:
-The polar solvent is water,
The first reagent is selected from a solvent-soluble zirconium and / or hafnium salt, zirconium and / or hafnium alkoxide, a zirconium and / or hafnium derivative soluble in an acidic medium in the solvent, preferably Selected from zirconium oxychloride and / or hafnium, zirconium oxynitride and / or hafnium, preferably selected from zirconium oxychloride and / or hafnium, and mixtures thereof;
The Zr ⁴⁺ and / or Hf ⁴⁺ ion concentration provided by the first reagent in the mother liquor is between 0.01 and 3 mol / l. This concentration may be higher than 0.1 mol / liter and / or less than 1.2 mol / liter,
-The second reagent is selected to provide SO ₄ ^2- and / or PO ₄ ^3-
-The concentration of the additive in the mother liquor is between 10 ^-5 mol / liter and 1 mol / liter. The concentration of the additive may be higher than 10 ^-3 mol / liter and / or less than 10 ^-1 mol / liter;
-The mother liquor is as follows:
-Acidity is between 0.6 and 2 mol / l;
^-The concentration of Zr ⁴⁺ and / or Hf ^{4+ in} the mother liquor is between 0.1 and 1.2 mol / l;
The molar ratio of anionic groups / (Zr ⁴⁺ and / or Hf ⁴⁺ ) is between 0.3 and 1, in particular between 0.6 and 1;
^-The concentration of the additive in the mother liquor is between 10 ^-3 and 10 ^-1 mol / liter; in step b)
^-The heating gradient is between 10 ^-2 and 1 ° C / min;
The heating temperature, i.e. the steady-state temperature is between 55 and 80 ° C, in particular between 55 and 70 ° C;
-The maintenance time in steady state is between 15 minutes and 2 hours.
-Preferably, the mother liquor is
After step b) or step c), optionally doped zirconium and / or hafnium derivatives,
After step d), optionally doped zirconium and / or hafnium hydrate, or after step e), optionally doped zirconium and / or hafnium oxide particles. Adapted to give powders containing more than 20%, more than 50%, more than 80%, more than 90%, or even more than 95%.
-The mother liquor is as follows:
-Acidity is between 1.6 and 3 mol / l;
^-The concentration of Zr ⁴⁺ and / or Hf ^{4+ in} the mother liquor is between 0.1 and 1.2 mol / l;
The molar ratio of anionic groups / (Zr ⁴⁺ and / or Hf ⁴⁺ ) is between 0.5 and 1, in particular between 0.5 and 0.8;
^-The concentration of the additive in the mother liquor is between 10 ^-5 and 10 ^-2 mol / liter; in step b)
^-The heating gradient is between 10 ^-2 and 1 ° C / min;
-Heating temperature is between 60 ℃ and 80 ℃;
-The maintenance time in steady state is between 1 hour and 10 hours.
-The mother liquor is as follows:
-Acidity is between 1.2 and 3 mol / l;
^-The concentration of Zr ⁴⁺ and / or Hf ^{4+ in} the mother liquor is between 0.1 and 1.2 mol / l;
The molar ratio of anionic groups / (Zr ⁴⁺ and / or Hf ⁴⁺ ) is between 0.8 and 2.0;
^-The concentration of the additive in the mother liquor is between 10 ^-3 and 10 ^-1 mol / liter; in step b)
^-The heating gradient is between 10 ^-2 and 1 ° C / min;
-Heating temperature is between 60 ℃ and 80 ℃;
-The steady state maintenance time is between 30 minutes and 2 hours.
-The mother liquor is as follows:
-Acidity is between 1.2 and 3 mol / l;
^-The concentration of Zr ⁴⁺ and / or Hf ^{4+ in} the mother liquor is between 0.1 and 1.2 mol / l;
The molar ratio of anionic groups / (Zr ⁴⁺ and / or Hf ⁴⁺ ) is between 0.3 and 1;
^-The concentration of the additive in the mother liquor is between 10 ^-5 and 10 ^-2 mol / liter; in step b)
^-The heating gradient is between 10 ^-2 and 1 ° C / min;
-The heating temperature is between 55 ℃ and 80 ℃;
-The steady state maintenance time is between 30 minutes and 2 hours.
-The mother liquor is as follows:
-Acidity is between 1.2 and 3 mol / l;
^-The concentration of Zr ⁴⁺ and / or Hf ^{4+ in} the mother liquor is between 0.1 and 1.2 mol / l;
The molar ratio of anionic groups / (Zr ⁴⁺ and / or Hf ⁴⁺ ) is between 0.3 and 1;
^-The concentration of the additive in the mother liquor is between 10 ^-3 and 10 ^-1 mol / liter; in step b)
^-The heating gradient is between 10 ^-2 and 1 ° C / min;
-Steady state temperature is between 60 ℃ and 80 ℃;
-The maintenance time in steady state is between 1 hour and 5 hours.
-The mother liquor is as follows:
-Acidity is between 0.6 and 3 mol / l;
^-The concentration of Zr ⁴⁺ and / or Hf ^{4+ in} the mother liquor is between 0.1 and 1.2 mol / l;
The molar ratio of anionic groups / (Zr ⁴⁺ and / or Hf ⁴⁺ ) is between 0.5 and 2;
^-The concentration of the additive in the mother liquor is between 10 ^-2 and 1 mol / liter; in step b)
^-The heating gradient is between 10 ^-2 and 10 ° C / min;
-The heating temperature is between 60 ° C and 100 ° C;
-The maintenance time in steady state is between 30 minutes and 5 hours.
-All dimensions of at least 80%, at least 90%, at least 95%, or even substantially 100% of the particles obtained after step b), c), d) or e) are greater than 50 nm is there.

The mother liquor described above makes it possible after step b) to obtain primary zirconium and / or hafnium derivatives having a solubility of less than 10 ⁻³ mol / l in water at temperatures below 20 ° C.

  In one embodiment, the parameters of steps a) and b) are determined after step b) to obtain anisotropic primary derivative particles.

  Preferably, to produce zirconium and / or hafnium oxide particles of a given size, in particular to produce base particles of all dimensions greater than 50 nm, greater than 200 nm, or even greater than 250 nm. Zirconium and / or hafnium derivatives or hydrate particles having dimensions are used as starting particles.

  According to a second main embodiment, the present invention relates to a method for the production of doped and undoped zirconium and / or hafnium hydrate particles powders and mixtures thereof, the method comprising starting particle powders A doped or undoped zirconium and / or hafnium derivative, preferably a doped or undoped zirconium sulfate and / or hafnium derivative, and a doped or undoped zirconium phosphate and / or hafnium. Derivatives selected from doped or undoped zirconium carbonate and / or hafnium derivatives, preferably doped or undoped zirconium basic sulfate and / or hafnium sulfate, doped or Undoped zirconium basic phosphate and / or A basic hydrolyzing step selected from nium phosphate and doped or undoped zirconium basic carbonate and / or hafnium carbonate, or a mixture thereof, or a starting powder In a mixture of such particles, wherein the starting particles are formed from aggregated or non-aggregated anisotropic basic particles.

  Thus, according to the invention, the method consists in hydrolyzing the starting particles of the zirconium and / or hafnium derivative in a basic medium to convert them into zirconium and / or hafnium hydrate particles. including.

  The hydrolysis step may in particular be step d) and in particular may include one or more of the optional features for step d). The powder of the starting particles may in particular be a powder produced by the production method according to the first main embodiment described above, in particular a powder obtained after step b) or step c). Good.

According to a third main embodiment, the invention relates to a powder of oxide particles of doped or undoped zirconium and / or hafnium, preferably ZrO ₂ , doped ZrO ₂ , HfO ₂ , doped HfO. _With respect to the production method _2, the method comprises starting powder of powder, doped or undoped zirconium and / or hafnium derivatives, doped or undoped zirconium and / or hafnium hydrate, Preferably doped or undoped zirconium sulfate and / or hafnium derivative, doped or undoped zirconium phosphate and / or hafnium derivative, and doped or undoped selected from a mixture thereof Zirconium carbonate and / or hafnium derivatives and doped or undoped zirconium And / or hafnium hydrates and mixtures thereof, preferably doped or undoped zirconium basic sulfate and / or hafnium sulfate and doped or undoped zirconium base Phosphate and / or hafnium phosphate, doped or undoped zirconium basic carbonate and / or hafnium carbonate, doped or undoped zirconium and / or hafnium hydrate, and A material selected from a mixture of: or a powder comprising a mixture of such starting particles, wherein the starting particles are agglomerated or non-agglomerated anisotropy Of basic particles or formed from these particles, where these particles are in hydrate form In some cases, the starting particles are also porous.

The firing step may be step e ₁ ) of the first main embodiment and may include one or more of the optional features of this step. The anisotropic starting particles may in particular be particles produced by the method according to the first main embodiment, and in particular can be obtained from steps b), c) or d).

  According to a fourth main embodiment, the present invention also relates to a method for producing a powder of doped and undoped zirconium and / or hafnium oxide particles and mixtures thereof, the method comprising: Preferably, the powder is selected from doped or undoped zirconium and / or hafnium derivatives, doped or undoped zirconium and / or hafnium hydrates, and mixtures thereof. Or undoped zirconium sulfate and / or hafnium derivatives, doped or undoped zirconium phosphate and / or hafnium derivatives, doped or undoped zirconium carbonate and / or hafnium derivatives, doped or Undoped zirconium and / or hafnium hydrate, Preferably a doped or undoped zirconium basic sulfate and / or hafnium sulfate and a doped or undoped zirconium basic phosphate and / or hafnium phosphorus selected from these mixtures Selected from acid salts, doped or undoped zirconium basic carbonates and / or hafnium carbonates, doped or undoped zirconium and / or hafnium hydrates, and mixtures thereof Including hydrothermal treatment of the material, or hydrothermal treatment of a mixture of these particles, wherein the starting particles are formed from agglomerated or non-agglomerated anisotropic basic particles The starting particles are also porous if they take the form of hydrates.

The hydrothermal treatment step is in particular step e, as in the case of the method according to the first main embodiment and including one or more optional features of step e ₂ ) of the first main embodiment. ₂ ). The starting particles may be produced by the method according to the first main embodiment, in particular from step b), c) or d).

In certain embodiments, the starting particle powder is:
-(For the second, third and fourth main embodiments) doped or undoped zirconium and / or hafnium derivatives, preferably doped or undoped zirconium sulfate and / or hafnium derivatives Selected from doped or undoped zirconium phosphate and / or hafnium derivatives and doped or undoped zirconium carbonate and / or hafnium derivatives, preferably doped or undoped zirconium basic Sulfates and / or hafnium sulfates, doped or undoped zirconium basic phosphates and / or hafnium phosphates, doped or undoped zirconium basic carbonates and / or hafnium carbonates Selected from
-(For third and fourth main embodiments) doped and undoped zirconium and / or hafnium hydrates,
Or only particles made of a material selected from a mixture of such particles, said starting particles being formed from aggregated or non-aggregated anisotropic basic particles, which are hydrated When taking the form, the starting particles are also porous.

In particular, according to this embodiment, the powder of the starting particles is `` Products of thermal hydrolysis in Zr (SO ₄ ) ₂ -Zr (OH) ₄ -H ₂ O system ''-Journal of the ceramic society of Japan, vol. It does not contain any zirconium and / or hafnium salts such as the particles used in the methods described in .102, No. 9, pp. 843-846.

(Product)
The method described above allows the discovery of several new particles.

  Steps a), b) and c) are preferably selected from doped or undoped zirconium and / or hafnium derivatives, preferably doped or undoped zirconium sulfate and / or hafnium derivatives and doped Selected or undoped zirconium phosphate and / or hafnium derivative, doped or undoped zirconium carbonate and / or hafnium derivative, and mixtures thereof, preferably doped or undoped Zirconium basic sulfate and / or hafnium sulfate, doped or undoped zirconium basic phosphate and / or hafnium phosphate, doped or undoped zirconium basic carbonate and / or hafnium Selected from carbonates and mixtures thereof The discovery of anisotropic base particles made of different materials.

  Accordingly, the present invention relates to a doped or undoped zirconium sulfate and / or hafnium derivative, preferably selected from doped or undoped zirconium and / or hafnium derivatives, and doped or undoped phosphorus. Preferably doped or undoped zirconium basic sulfate and / or selected from zirconium acid and / or hafnium derivatives, doped or undoped zirconium carbonate and / or hafnium derivatives, and mixtures thereof Or hafnium sulfate, doped or undoped zirconium basic phosphate and / or hafnium phosphate, doped or undoped zirconium basic carbonate and / or hafnium carbonate, and Mixture, or grains of them More than 20%, 50%, 80%, 90%, or even 95% of the aggregated or non-aggregated anisotropic base particles made of a material selected from It also relates to super-containing powders.

  In a preferred embodiment, these particles are dense.

  In another embodiment, these particles are porous, especially when a pore former is added in step a).

  These base particles are insoluble in water and are preferably hydrolysable.

  Preferably, these base material materials are amorphous when not doped. However, if this material is doped, it may have crystals formed from the dopant. In other words, on the X-ray diffraction diagram, substantially all of the peaks corresponding to the detection of the crystals correspond to the crystals containing the dopant.

  Steps a), b), optionally c), and d) are agglomerated or agglomerated made of doped or undoped zirconium and / or hafnium hydrates and mixtures thereof. There has been no discovery of porous anisotropic base particles.

  Thus, the present invention relates to agglomerated or non-agglomerated porous anisotropic bases made of doped or undoped zirconium and / or hafnium hydrates or mixtures of such hydrates It also relates to powders containing more than 20%, more than 50%, more than 80%, more than 90% or even more than 95% of the particles. The base particles may have the same or different chemical composition.

  Preferably, the material of these particles is amorphous when not doped. However, if this material is doped, it may have crystals formed from dopants.

Steps a), b), optionally c), d), and e1) (calcination) and steps a), b), optionally c), d), and e2) (hydrothermal treatment) are: Agglomerates made of doped or undoped zirconium and / or hafnium oxides and mixtures thereof, preferably materials selected from ZrO ₂ , doped ZrO ₂ , HfO ₂ , or doped HfO ₂ Has led to the discovery of porous anisotropic base particles that have been or have not been agglomerated.

  Accordingly, the present invention is agglomerated or non-agglomerated made of a material selected from doped or undoped zirconium and / or hafnium oxides and mixtures thereof, or a mixture of these particles It also relates to a powder comprising more than 20%, more than 50%, more than 80%, more than 90% or even more than 95% of porous anisotropic base particles.

  Preferably, the material of these particles is crystalline.

The present invention relates to an agglomerated or non-agglomerated dense material made of a material selected from zirconium and / or hafnium oxides, doped zirconium and / or hafnium oxides, and mixtures thereof. For powders containing more than 20%, 50%, 80%, 90% or even 95% anisotropic base particles, this dopant is
-An oxide of an element selected from yttrium Y, lanthanum La, cerium Ce, scandium Sc, calcium Ca, magnesium Mg, and mixtures thereof, the dopant is preferably in a molar amount of 20% or less, preferably It is a solid solution with zirconium oxide and / or hafnium oxide. The product according to the invention may in particular be zirconia doped with yttrium oxide or zirconia doped with cerium oxide;
An oxide of aluminum Al, preferably in a molar amount of not more than 20%, more preferably not more than 3%, preferably dispersed in an oxide of zirconium and / or hafnium;
-And their mixtures.

  Preferably, the powder base particles take the form of platelets and / or needles and / or agglomerate in the form of stars and / or leaflets and / or archins and / or hollow spheres. Even more preferably, the base particles take the form of platelets and / or agglomerate in the form of leaflets and / or stars, archins and / or hollow spheres.

  Preferably, the material of these particles is crystalline.

According to certain embodiments, the present invention provides that the maximum size is less than 200 μm and the number of aggregated or non-aggregated anisotropic base particles is greater than 20%, greater than 50%, greater than 80%, 90% For powders of particles containing more than 95% and even more than 95%,
-Dense or porous made of doped or undoped water-insoluble and hydrolyzable zirconium and / or hafnium derivatives that are amorphous or contain only crystals containing dopants as single crystals Base particles, said zirconium derivative possibly comprising zirconium basic sulfate and / or hafnium sulfate, zirconium basic phosphate and / or hafnium phosphate, and zirconium basic carbonate and / or hafnium carbonate Base particles that are specially selected from, and mixtures thereof;
-Porous base particles of doped or undoped zirconium and / or hafnium hydrate, which are amorphous or contain only crystals containing dopants as single crystals;
-Porous base particles of doped or undoped zirconia ZrO ₂ and / or hafnium oxide HfO ₂ ;
-Are selected from the group formed by a mixture of these base particles.

Preferably, in particular,
-For porous base particles made of doped or undoped water-insoluble and hydrolyzable zirconium and / or hafnium derivatives that are amorphous or contain only crystals containing the dopant as a single crystal ,and
-For porous base particles of doped or undoped zirconium and / or hafnium hydrate, which are amorphous or contain only crystals containing the dopant as a single crystal, and
-For porous base particles of doped or undoped zirconia ZrO ₂ and / or hafnium oxide HfO ₂
Said powder has a porosity index Ip higher than 2, preferably higher than 5, preferably higher than 10, or even higher than 20 or even higher than 50.

  In the case of the porous base particles of zirconium and / or hafnium hydrate, the powder preferably has a porosity index Ip higher than 80 and even higher than 100.

  In order to produce a high porosity, in particular a porosity index higher than 2, in the case of said porous base particles made with a derivative of zirconium and / or hafnium and made using the method according to the invention, pore formation It is necessary to add the mother liquor of the agent.

When the porous base particles are made of doped or undoped zirconium and / or hafnium derivatives, the powder is more than 10 m ² / g, or even more than 20 m ² / g, more than 40 m ² / g, 50 m ² / g, greater than 70m ² / g greater, may have a specific surface area of 100 m ² / g greater than the total volume of mesopores and micropores of the powder, 0.05 cm ³ / g, or greater than Furthermore, it is more than 0.08 cm ³ / g, or more than 0.10 cm ³ / g.

When the porous base particles are made of doped or undoped zirconium and / or hafnium hydrate, the powder is more than 100 m ² / g, more than 200 m ² / g, more than 250 m ² / g, 300 meters ² / g greater, and / or 380m may have a specific surface area of less than ² / g, the total volume of mesopores and micropores of the powder, 0.10 cm ³ / g, greater than 0.15 cm ³ It may be greater than / g, greater than 0.20 cm ³ / g, and / or less than 0.30 cm ³ / g.

Where the porous base particles are made of zirconia ZrO ₂ and / or hafnium oxide HfO ₂ , the powder is greater than 20 m ² / g, greater than 50 m ² / g, greater than 70 m ² g, greater than 100 m ² / g, and / or may have a specific surface area of less than 200 meters ² / g, the total volume of mesopores and micropores of the powder, 0.08 cm ³ / g greater, 0.10 cm ³ / g greater, 0.20 cm ³ It may be greater than / g and / or less than 0.30 cm ³ / g.

In the case of powders with particles of all dimensions greater than 50 nm (i.e. when more than 95% of the base particles all have dimensions greater than 50 nm), we have the characteristic “specific surface area of 10 m ² / “A greater than g and the sum of the volume of mesopores and micropores is greater than 0.05 cm ³ / g” is considered substantially equivalent to the characteristic “porosity index Ip is 2 or greater”.

Thus, the present invention provides a characteristic “specific surface area greater than 10 m ² / g when the characteristic“ porous Ip of 2 or more ”or the characteristic“ porous ” Relates to a powder of particles as described above, wherein the sum of the volume of the mesopores and micropores is replaced by “greater than 0.05 cm ³ / g”.

In contrast, the present invention is characterized by the characteristic “less than 2 Ip” or the characteristic “dense” that the characteristic surface area is less than 10 m ² / g. And the sum of the volume of the mesopores and the micropores is less than 0.05 cm ³ / g ”.

The dense base particles of the powder according to the invention are doped or undoped zirconium and / or hafnium derivatives, in particular doped or undoped zirconium basic sulfate and / or hafnium sulfate, doped or non-doped. When made of doped zirconium basic phosphate and / or hafnium phosphate, doped or undoped zirconium basic carbonate and / or hafnium carbonate, or a mixture of these derivatives, the powder is , Having a specific surface area of less than 7 m ² / g, and the sum of the volume of the mesopores and micropores of the powder may be less than 0.05 cm ³ / g.

When the dense base particles of the powder according to the invention are made of zirconia ZrO ₂ and / or hafnium oxide HfO ₂ , the powder has a specific surface area of less than 7 m ² / g, or even less than 5 m ² / g. The sum of the mesopore and micropore volumes of the powder may be less than 0.02 cm ³ / g.

  In general, the invention relates to a powder obtained or obtainable by the process according to the invention, in particular via a process comprising a step e1) of calcination at temperatures below 1200 ° C.

The powder according to the invention may comprise one or more of the following optional features:
_-The maximum size (D _99.5 ) of the particles (base or agglomerated) of the powder is less than 150 μm, less than 100 μm, less than 80 μm, or less than 50 μm;
-The particles are water-insoluble;
-Base particles are more than 20%, 50%, 80%, 90%, or even more than 95%, or even substantially 100% of the number of particles constituting independent or agglomerated particles Having a shape selected from platelets, in particular platelets with a thickness greater than 50 nm, in particular needles longer than 200 nm;
The particles are at least 80% by number, preferably at least 90%, or even substantially 100% in the following form:
-Layered, especially formed from 2 to 50 platelets,
-Stars that contain in particular tapered and / or straight branches, or only such branches, in particular 3 to 15 branches, and preferably more than 3, 4 or 5 branches; and
-Regularly agglomerated particles in one of the spheres, preferably in the form of hollow spheres, preferably with a sphericity index greater than 0.7,
And / or irregularly agglomerated particles, especially particles in the form of archin;
-Agglomerated particles can be obtained in particular from needle or platelet base particle assemblies. These base particles may assemble themselves into the form of aggregated particles that are intermediates. For example, the agglomerated particles may be formed from a star assembly or from a star and needle assembly;
-Agglomerated particles are formed from base particles with all dimensions greater than 250 nm;
-All dimensions of the base or agglomerated particles are greater than 50 nm, greater than 100 nm, greater than 200 nm, greater than 250 nm, greater than 500 nm, or even greater than 600 nm. A size greater than 50 nm is particularly advantageous for producing pores that diffuse gas well, thus achieving good catalyst or filtration performance qualities. The particles may be anisotropic, in particular platelet-shaped or needle-shaped, in particular longer than 200 nm;
-At least 95% or even substantially 100% of the base particles have a shape such that all their dimensions are greater than 50 nm;
-The base particles have a different shape than in the case of platelets, needles or leaflets, especially if they have at least one dimension of less than 50 nm;
-The particles are doped, and the dopant of the particles is from a compound of elements selected from yttrium Y, scandium Sc, cerium Ce, silicon Si, sulfur S, aluminum Al, calcium Ca, and magnesium Mg, and mixtures thereof Selected;
When the particles are zirconia and / or hafnium oxide particles, the dopant compound may in particular be as follows:
An oxide of an element selected from Y, La, Ce, Sc, Ca, Mg, and mixtures thereof, with a solid solution having zirconium oxide and / or hafnium oxide, preferably in a molar amount of 20% or less some stuff. The present invention particularly relates to a powder of zirconia doped with yttrium oxide or zirconia doped with cerium oxide;
-An oxide of an element selected from Si, Al, and S, and mixtures thereof, dispersed in zirconium oxide and / or hafnium oxide. When the oxide is aluminum oxide, the molar amount is preferably 20% or less, more preferably 3% or less;
When the particles are zirconium and / or hafnium hydrate particles, the dopant compound may in particular be as follows:
A hydrate of an element selected from Y, La, Ce, Sc, Ca, Mg, and mixtures thereof, preferably as a close molar mixture with zirconium and / or hafnium hydrate, preferably 20 Those in a molar amount of less than%. The present invention particularly relates to mixed zirconium yttrium hydrate and / or mixed zirconium cerium hydrate powders;
-Aluminum hydrate dispersed in zirconium and / or hafnium hydrate, preferably in a molar amount of preferably 20% or less, more preferably 3% or less;
-An oxide of an element selected from Si, S, and mixtures thereof, dispersed in a hydrate of zirconium and / or hafnium;
If the particles are particles of zirconium and / or hafnium derivatives, the dopant compound may in particular be as follows:
-Derivatives of elements selected from Y, La, Ce, Sc as an intimate molar mixture with zirconium and / or hafnium derivatives, preferably in a molar amount of 20% or less. The present invention relates in particular to powders of mixed derivatives of zirconium and yttrium, or mixed derivatives of zirconium and cerium;
-A salt of an element selected from Ca, Mg, and mixtures thereof as an intimate molar mixture with zirconium and / or hafnium derivatives, preferably in a molar amount of 20% or less;
-Preferably in a molar amount of 20% or less, more preferably 3% or less, as a close molar mixture with zirconium and / or hafnium derivatives, or localized on the surface of zirconium and / or hafnium derivatives, Aluminum hydrate;
-Oxides of elements selected from Si, S, and mixtures thereof, as an intimate molar mixture with zirconium and / or hafnium derivatives, or localized on the surface of zirconium and / or hafnium derivatives;
-Preferably, the molar amount of dopant is determined to be less than 40%, or even less than 20%, or even less than 10%, or even less than 5%, or even less than 3% of the mass of the material of the particles ;
- particles preferably have a 10 m ² / super or even 20 m ² / g greater, or even 50 m ² / g greater, or even a specific surface area of 100 m ² / g greater than,. The total volume of mesopores and micropores of the powder is preferably 0.05 cm ³ / g greater, or even 0.1 cm ³ / g greater or even 0.15 cm ³ / g greater;
-Regardless of the embodiment, preferably the content of impurities of the powder according to the invention is less than 0.7%, preferably less than 0.5%, preferably less than 0.3%, more preferably less than 0.1% as a mass percentage of dry matter. is there.

The invention also relates to a powder having a maximum particle size of less than 200 μm (D _99.5 ) and a porosity index Ip of less than 2, which porosity index is equal to the ratio A _sr / A _sg ,
-A _sg is the theoretical geometric specific surface area calculated from the determination of powder shape and particle size;
-A _sr is the actual specific surface area measurement by BET;
The powder is
-Has a sphericity index of less than 0.6,
-Agglomerated in the shape of a star, especially containing 3 to 15 tapered and / or straight 0 branches, or a leaflet formed from 2 to 50 platelets, and
^-From zirconium and / or hafnium oxides of the formula MO _x [M is Zr ⁴⁺ , Hf ⁴⁺ , or a mixture of Zr ⁴⁺ and Hf ⁴⁺ , where x is a non-zero positive number] Contains more than 20% of the formed base particles.

  Unless it is incompatible with this embodiment, the features of the powder according to the previous embodiment are applicable to this powder.

The invention also relates to a powder having a maximum particle size of less than 200 μm (D _99.5 ) and a porosity index Ip of less than 2, which porosity index is equal to the ratio A _sr / A _sg ,
-A _sg is the theoretical geometric specific surface area calculated from the determination of powder shape and particle size;
-A _sr is the actual specific surface area measurement by BET;
The powder is
-Has a sphericity index of less than 0.6,
^-From zirconium and / or hafnium oxides of the formula MO _x [M is Zr ⁴⁺ , Hf ⁴⁺ , or a mixture of Zr ⁴⁺ and Hf ⁴⁺ , where x is a non-zero positive number] Containing more than 20% of the base particles formed, provided that said oxide, known as "first oxide"
-A second oxide of an element selected from Y, La, Ce, Ca, Mg, and mixtures thereof, which is a solid solution with the first oxide;
-A second oxide of an element selected from Si, Al, S, and mixtures thereof dispersed in the first oxide;
-And are doped using dopants selected from mixtures thereof.

  Unless it is incompatible with this embodiment, the characteristics of the powder according to the above-described embodiment are applicable to this powder.

  Preferably, the base particles have a platelet shape and / or are aggregated in the form of stars and / or leaflets and / or archins and / or hollow spheres.

  The present invention is particularly applicable to extrusion, granulation (e.g. by atomization), injection molding, pressing (unidirectional pressing, hot pressing, CIP, HIP, etc.), casting (slip casting, strip casting, etc.), coating (centrifugal A structural material produced via a technique (such as by separation or `` spin coating '', by dip or `` dip coating '') and having a density greater than 98% of the theoretical density of the material comprising it, Substances with a porosity index Ip> 2, a coating with a thickness less than 1 mm and a porosity index Ip> 2 or having a density higher than 98% of the theoretical density of the material constituting it, in particular a catalyst coating or “wash coating” A structure selected from coatings obtained, for example, by dip coating or by spin coating or by strip casting Regarding the quality, the substance or the coating is obtained from the powder according to the invention.

  The present invention relates to a catalyst, a catalyst carrier, particularly a filtration element for treating a gas or liquid, a fuel cell element, particularly an anode or electrolyte, particularly a SOFC type fuel cell, a piezoelectric material, an optical connector, etc. Of the powders according to the invention or of the substances according to the invention as dental ceramics or more generally as structural ceramics, ie in any application where good mechanical properties and / or good wear resistance are desired Also related to use.

  The invention relates to a catalyst, a catalyst support, in particular a filtering element for treating a gas or liquid, a fuel cell element, in particular an anode or electrolyte, in particular a SOFC type fuel cell, a piezoelectric material, an optical connector, a dental ceramic, or more In general, structural ceramics, i.e. components with good mechanical properties and / or good wear resistance, which are notable to contain or be derived from the powder according to the invention. Also related.

  Other features and advantages of the present invention will become apparent upon reading the following detailed description and upon examining the accompanying drawings.

2 is a scheme describing the main steps of the method according to the invention. It is a scheme of needle-shaped particles. It is a scheme of particles in the form of platelets. It is a scheme of a leaf-shaped particle. This is a scheme of a star-shaped particle. It is a scheme of particles in the shape of hollow spheres. It is a photograph of particle powder. It is a photograph of particle powder. It is a photograph of particle powder. It is a photograph of particle powder. It is a photograph of particle powder. It is a photograph of particle powder. It is a photograph of particle powder. It is a photograph of particle powder.

(Definition)
Percentiles or “centiles” 0.5 (D _0.5 ), 50 (D ₅₀ ), and 99.5 (D _99.5 ) have mass percentages of 0.5%, 50%, and 99.5%, respectively, on the cumulative particle size distribution curve of the powder size. The size of the corresponding powder particle, and the particle size is classified in ascending order. For example, 99.5% by weight of the powder particles have a size of less than D _99.5 , and 0.5% by weight of the particles have a size of greater than D _99.5 . 0.5% by weight of the particles of the powder has a size of less than D _0.5 . Percentiles may be determined using a particle size distribution formed using a cedi graph. The Sedigraph used herein is Sedigraph 5100 manufactured by Micromeritics®.

D ₅₀ corresponds to the “median size” of the assembly of particles, ie, the size that divides the particles of this assembly into first and second populations of equal mass, and these first and second populations Contains only particles each having a size larger or smaller than the median size.

The term “maximum size of powder particles” means the 99.5 percentile (D _99.5 ) of the powder.

  A “powder” is an assembly of particles. These particles may be “base” particles, ie those that are not bound to other base particles, “agglomerated” or “aggregated” particles. Unlike simple agglomerates of base particles, agglomerated particles, also referred to as “aggregates”, are not easily dissociated and resistant, for example, when ultrasound is applied. Traditionally, the bonds between the base particles of agglomerated particles are chemical bonds, whereas in agglomerates, the bonds are obtained from the action of charge or polarity.

  In the description of the present invention, the term “particle” means base particles and aggregates.

  The term “impurity” means an inevitable component that is necessarily introduced with the starting material, or a component that results from a reaction with these components. Thus, as used herein, the term “impurity” refers to any compound other than zirconium and / or hafnium compounds (derivatives, hydrates, or oxides) and optional dopant (s). Means an element. The content of impurities of “hydrate” or “derivative” is measured after calcination at 1000 ° C. In the case of derivatives, the element (s) of the anionic group (s) of said derivative are not considered impurities. For example, after firing ZBS at 1000 ° C., residual sulfur is not considered an impurity.

The term "dopant" or "dopant compound" in the product means a minor component, i.e. a component that is not the component with the highest molar content in the material under consideration. For example, zirconia doped with alumina contains the following molar amounts of alumina in the case of zirconia. On the other hand, for example, `` Preparation of Mesoporous Ce _0.5 Zr _0.5 O ₂ Mixed Oxide by Hydrothermal Templating Method '', Journal of Rare Earths 25, 2007, pages 710-714, the formula Ce _0.5 Zr _0.5 O ₂ The compound cerium oxide is not a dopant.

By extension, the term “dopant” also refers to the chemical species introduced during the manufacturing process of the doped product. The latter dopant may be the same as or different from the dopant present in the doped product, i.e. may constitute a precursor of the dopant present in the doped product. The dopant present in the doped product is then also referred to as the “successor” of the dopant introduced during the manufacture of the doped product. For example, zirconium basic sulfate doped with yttrium basic sulfate can be obtained by adding YCl ₃ .

The dopant of the particles is
-In particles that take the following form:
○ a defined compound (e.g., ZrOSO _4, ZrCeO _4), or a solid solution or intimate molecular mixture, _{(e.g., (Zr x Y y) BS} , (Zr x Ce y) O 2, where x + y = 1) And / or ○ a dispersion (e.g., a dispersion of alumina dispersed in zirconia particles), and / or ○ in a particle that takes the form of an inclusion body,
-And / or on the surface of its particles,
It may be localized.

The term “derivative” generally means a compound of the formula M (OH) _x (N ′) _y (OH ₂ ) _z where M is a metal cation or a mixture of metal cations and N is an anion or A mixture of anions, the subscripts x and y are exact positive numbers, the subscript z is positive or zero, and the compound is 10 ^-3 moles relative to water at temperatures below 20 ° C. (e.g., `` Zirconia Needles Synthesized Inside Hexagonal Swollen Liquid Crystals '', Chemistry of Materials, 2004, Volume 16, pages 4187-4192, resulting in oxy Different from zirconium salts such as zirconium chloride octahydrate). The anion may be inorganic (Cl ⁻ ) or organic (acetic acid CH ₃ —COO ⁻ ), single atom (F ⁻ ) or polyatomic (SO ₄ ²⁻ ).

In particular, when M is Zr ₄ ⁺ , Hf ₄ ⁺ , or a mixture of Zr ₄ ⁺ and Hf ₄ ⁺ , the derivative shall be called “zirconium derivative”, “hafnium derivative”, or “zirconium and hafnium derivative”, respectively. become.

  Steps b) and c) make it possible in particular to produce zirconium and / or hafnium derivatives.

  Unless otherwise indicated, in the description and claims of the present invention, a “derivative” is a derivative that can be produced via the process according to the invention.

The term “zirconium basic sulfate” or “ZBS” has the general formula Zr (OH) _x (SO ₄ ) _y (H ₂ O) _z , where y is between 0.2 and 2 and x is x + 2y = 4, and z is a positive number or 0].

The term `` zirconium basic carbonate '' or `` ZBC '' has the general formula Zr (OH) _x (CO ₃ ) _y (H ₂ O) _{z where} y is between 0.2 and 2 and x is x + 2y = 4, and z is a positive number or 0].

The term “zirconium basic phosphate” has the general formula Zr (OH) _x (PO ₄ ) _y (H ₂ O) _z , where y is between 0.2 and 2 and x is x + 3y = 4 is a value such that z is a positive number or 0].

The term “salt” has the formula M (OH) _x (N ′) _y (OH ₂ ) _z , where M is a metal cation or a mixture of metal cations, and N ′ is an anion or anion. Is a mixture, subscripts x, y, and z are positive or 0, x + y> 0, and have a solubility greater than 10 ⁻³ mol / l in water at temperatures below 20 ° C.] Means a compound of The anion may be inorganic (Cl ⁻ ) or organic (acetic acid CH ₃ —COO ⁻ ), single atom (F ⁻ ), or polyatomic (SO ₄ ²⁻ ). In the case of zirconium, typical salts are zirconium oxychloride Zr (OH) ₂ Cl ₂ (OH ₂ ) ₄ , zirconium chloride ZrCl ₄ , and zirconium sulfate Zr (SO ₄ ) ₂ .

The term “zirconium oxychloride” or “ZOC” means a crystalline zirconium salt of the formula Zr (OH) ₂ Cl ₂ (OH ₂ ) ₄ .

The term “hydrate” is conventionally referred to as the formula MO _x (OH) _y (OH ₂ ) _z , where M is a metal cation or a mixture of metal cations, and the subscripts x and z are positive or 0, the subscript y is a positive number, and 2x + y is equal to the valence of a cation or the average valence of a mixture of cations). For example, zirconium hydrate or “ZHO” has the formula ZrO _x (OH) _y (OH ₂ ) _z , where z ≧ 0, y ≧ 0, and 2x + y = 4.

In particular, when M is Zr ₄ ⁺ , Hf ₄ ⁺ , or a mixture of Zr ₄ ⁺ and Hf ₄ ⁺ , the hydrates are “zirconium hydrate”, “hafnium hydrate”, or “zirconium hafnium, respectively”. It will be called “hydrate”. When x and z are 0, the hydrate will have the formula Zr (OH) ₄ and will also be referred to as “zirconium hydroxide”.

According to this definition, a zirconium hydrate having the type of the general formula ZrO ₂ · n (H ₂ O) is not a hydrate within the meaning of the invention.

By definition, a hydrate has a solubility of less than 10 ⁻³ mol / l in water below 20 ° C.

  Unless otherwise indicated, in the description and claims of the present invention, a “hydrate” is a hydrate that can be produced via the process according to the present invention.

The term “oxide” conventionally refers to a compound of the formula MO _{x where} M is a metal cation or a mixture of metal cations and x is a positive number other than 0. For example, zirconia ZrO ₂ is zirconium oxide.

In the specific case of sulfur and phosphorus, the oxide form of the compound also includes all oxide compounds of sulfur and phosphorus, respectively. The sulfur oxide compound is, for example, SO ₄ ^2- , and the phosphorus oxide compound is, for example, PO ₄ ^3- .

  On the contrary, in the description and claims of the present invention, unless otherwise indicated, “oxide” is an oxide that can be produced via the method according to the invention.

The term “oxoanion” is conventionally referred to as the formula QOx ⁿ , where Q is a metal (eg, silicon) or non-metal (eg, carbon, phosphorus, or sulfur) and n is an integer greater than or equal to 1. , X is equal to (n + w) / 2, where w is the valence of the metal or nonmetal under consideration].

  The term “calcination” refers to a heat treatment to convert the product to the oxide form. Typically, the calcination is performed at a temperature of 500 ° C. or higher.

  The term “drying” means a heat treatment that is generally performed at a temperature below 400 ° C. to remove all of the solvent or only the solvent that does not precipitate in the components of the dry product. For example, when the solvent is water, it is possible to remove water other than the water constituting the hydrate by drying the zirconium hydrate. Unlike calcination, drying does not result in conversion of the treated product to the oxide form.

The term “open porosity” means the porosity that can be attributed to all accessible pores of the formed powder or material in solid form. According to the classification of the International Union of Pure and Applied Chemistry, 1994, 66, No. 8, pp. 1739-1758, accessible pores are classified into three categories according to their equivalent diameter:
-Macropores are accessible pores with an equivalent diameter of more than 50 nm;
-Mesopores are accessible pores with an equivalent diameter between 2 and 50 nm;
-Micropores are accessible pores with an equivalent diameter of less than 2 nm;
The equivalent diameter of the pore is defined by the minimum dimension of the pore as shown in the IUPAC document. For example, when the pore is cylindrical, the equivalent diameter is the diameter of the cylinder.

  “Open porosity” is the sum of macroporosity, mesoporosity, and microporosity.

  In each of the above categories, “pore volume” means the volume occupied by the accessible pores of a particle, relative to the mass of the powder or substance under consideration. “Macropore volume”, “mesopore volume”, and “micropore volume” are the volumes relative to the mass of the powder or solid corresponding to the macropores, mesopores, and micropores, respectively.

  Macropore volume is conventionally measured by mercury porosimetry; mesopore volume and micropore volume are conventionally measured by nitrogen adsorption and desorption at -196 ° C.

  A “pore-forming” agent is an agent that, when introduced into the mother liquor in step a), results in the formation of pores that are largely open to the particles.

The term “porosity index” Ip of a powder or substance of particles means the ratio A _sr / A _sg ,
-A _sg is the theoretical geometric specific surface area calculated from the determination of the shape and particle size of the powder or substance;
-A _sr is a measurement of actual specific surface area by BET.

Thus, when I _p = 1, ie when A _sr = A _sg , the powder or particles of the substance have no open porosity and are completely dense.

actually,
O If I _p ≥ 2, i.e., A _sr ≥ A _sg , the particles of the powder or substance have a significant open porosity, referred to herein as "porous particles";
O If I _p <2, the powder or substance particles have insufficient porosity, referred to herein as “dense particles”.

  The porosity index characterizes the open porosity (microporosity, mesoporosity, and macroporosity) of powder or substance particles.

The terms “porous aggregate”, “porous agglomerate”, and “porous solid material” mean an agglomerate, agglomerate, or solid material, respectively, with a porosity index of I _p ≧ 2.

When referring to two compounds and “mixtures thereof”, this expression is not only a mixture of these two compounds and these compounds in which the particles of these compounds are clearly distinguishable, but also a solid solution and / or a closeness of these compounds. Including molecular mixtures. The “mixture” of the zirconium compound and the hafnium compound includes, for example, a solid solution of zirconium and hafnium (Zr, Hf), and a mixture of ZrO ₂ grains and HfO ₂ grains.

The acidity of the solution or suspension is equal to the concentration of H ⁺ ions in the solution or suspension, [H ⁺ ]. The acidity of the solution or suspension is equal to 10- ^pH . Acidity is expressed in moles / liter.

  The term “texture property” refers to the physical surface properties that characterize the formed powder or solid material: specific surface area, mesopore volume, micropore volume, macropore volume, pore size distribution, and average Match all pore sizes.

  The term “base particles” means “basic” particles, in particular particles in the form of needles or platelets.

  The term “needle” means an elongated, generally shaped anisotropic particle, ie, an anisotropic particle that extends primarily along linear or non-linear guidelines. However, the length L measured along these guidelines is less than 50 times the width “l”, and this width “l” should be measured at all cross-sections (perpendicular to the guidelines) along the guidelines. Is the maximum possible dimension. Further, the minimum dimension measured at the cross-section where thickness “e”, ie, width “l” is measured, is greater than 0.5 times the width “l”.

  The needle is represented schematically in FIG. 2a. Figures 3b and 3c are photographs of acicular powder.

  The cross section of the needle, ie the cross section perpendicular to the direction of the guideline defining its length, may be of any shape, in particular a polygon, or may be oval or circular.

  According to the present invention, preferably 1.67 <L / l <50, preferably 2 <L / l, more preferably 5 <L / l. Preferably, L / l <20, more preferably L / l <10.

  The term “platelet” means a particle having a width and a relatively narrow overall shape, such as a thin plate. In other words, the platelet has two wide surfaces that are generally substantially parallel to each other, separated from each other by a short distance relative to the dimensions of the surface. The platelet is represented schematically in FIG. 2b. FIG. 3f is a photograph representing a platelet (mixed with particles in the form of “tufts”).

  More specifically, a particle is a platelet if its length “L” corresponding to the maximum measurable dimension on one of the two broad sides of the particle is less than 1.5 times the width “l”. This width “l” is the largest dimension that can be measured on all cross sections along the length (perpendicular to the length), and the thickness “e”, ie the width “l”, is measured. If the minimum dimension measured at the cross-section is less than 0.5 times the width “l”, it is considered a platelet.

  According to the present invention, when e, L, and l indicate the thickness, length, and width of the platelet, respectively, preferably e ≦ 0.25 × l, preferably e ≦ 0.22 × l, and / or L ≦ 1.2 × l.

  Preferably, according to the invention, the cross section perpendicular to the thickness direction is substantially constant over the entire thickness of the platelet.

  Also preferably, according to the present invention, the cross section perpendicular to the thickness direction has more than seven sides, or has an oval or circular overall shape.

  Among the agglomerates, “regular” and “irregular” shapes are distinguished depending on whether or not the base particles are arranged so that agglomerates of a defined overall shape are formed. Among the regular shapes, leaflets, stars and spheres are particularly distinguished, especially hollow spheres.

  The term “leaflet” means particles formed from a flat stack of at least two platelets of similar size, preferably a highly overlapping stack. In other words, the platelets are similar and are in contact via their wide surfaces, preferably significantly overlapping each other. The leaflets are represented schematically in FIG. 2c.

Preferably, for the purposes of the description and claims of the present invention, the leaflets have W1 ′ / W1 ≦ 1.5 and W2 ′ / W2 ≦ 1.5,
-W1 and W2 respectively indicate the major and minor axes of the smallest ellipse that each of the platelets that make up the leaflet can pass through in its thickness direction (i.e., laid flat)
-W1 'and W2' denote the major and minor axes of the smallest ellipse through which the leaflets can pass along the stacking direction, respectively.

  Preferably, according to the invention, the leaflets comprise less than 50, preferably less than 20 platelets.

  More preferably, according to the present invention, W1 ′ / W1 ≦ 1.2 and W2 ′ / W2 ≦ 1.2, more preferably W1 ′ / W1 ≦ 1.1 and W2 ′ / W2 ≦ 1.1, and W1, W2, W1 'And W2' are as defined above.

  The term “star” means particles formed from an assembly of at least two needles according to the present invention, optionally of different sizes, these needles being substantially intersected at the center of the star . The stars are represented schematically in Figure 2d. Aggregates of needles that form stars can be seen in the picture of Figure 3d. A star is obtained by attaching several needles substantially in the middle of its length and / or by growing several needles from the same nucleus (forming the core of the star) be able to.

  The term “L” of a star means the length of the long axis of the smallest ellipse that can inscribe the star (see FIG. 2d).

  Preferably, the number n ′ of needles constituting the star is less than 15, preferably less than 8.

  The term “archin” means a particle formed from an irregularly shaped assembly of base particles, in particular the needles and / or platelets according to the invention. Thus, archin is an amorphous potato shape in the sense that the overall shape of one archin can be very different from another archin. The aggregation of the needles and stars forming the archin can be seen in the picture of Fig. 3e.

  The term `` hollow sphere '' is D / D ′ ≦ 2 when D indicates the maximum outer diameter of the particle (its maximum outer dimension) and D ′ indicates the maximum inner diameter of the cavity (its maximum inner dimension). Means an isotropic particle having a central cavity. The hollow sphere is schematically represented in the cross section of FIG. Agglomeration of the needles forming the hollow sphere can be seen in one of the pictures in Figure 3g.

  The hollow sphere according to the invention is preferably formed from a needle.

  Preferably, according to the invention, the sphericity index of the hollow sphere is greater than 0.7, more preferably greater than 0.8.

  The term “sphericity index” refers to the ratio between the minimum and maximum dimensions of a particle, and these dimensions are “between ends” along an axis that passes through the particle's baric center. Measured.

  A particle is said to be “isotropic” if its sphericity index is greater than 0.6.

  A particle is said to be “anisotropic” if its sphericity index is between 0.02 and 0.6. For example, 0.02 is the sphericity index of a needle whose length L is 50 times the thickness e. The sphericity index may be greater than 0.05 (the ratio of length to thickness is equal to 20) or even greater than 0.1 (L / e ratio is 10). The sphericity index may be less than 0.5, or even less than 0.4, or even less than 0.35, or even less than 0.3.

  The term “starting particle” means a particle used to carry out the process according to the invention. Thus, the nature of the starting particles varies depending on the method under consideration.

  In all formulas of compounds, the suffix conventionally represents the number of moles.

(Method of characterization)
Particle morphology other than hollow spheres The presence of particles having a granular morphology is generally possible by observing a scanning electron microscopy image as shown in the figure.

  These images also allow evaluation of particle size. In particular, if the observed powder particles appear to have substantially the same morphology, it is possible to determine an average dimension for all of these particles.

Hollow sphere morphology After coating of the sample to be characterized with resin and final polishing (finishing with micron-sized diamond paste), images containing between 10 and 50 hollow spheres using scanning electron microscopy The initial magnification (× 100) used at this time is adapted to reach the number of observed hollow spheres. A large number of images are required, and generally more than 50 images are required. First, since the orientation of each hollow sphere is random, and second, the random cross section of each hollow sphere is made possible by polishing, from which the internal structure (cavity) can be determined. From these images, it is also possible to evaluate the maximum outer diameter of cavity D and the maximum inner diameter of cavity D ′ as an average of the assembly of particles.

Chemical analysis Chloride ion Cl ^- is assayed after high temperature hydrolysis by ion chromatography. Carbonic acid (CO ₃ ^2- ) and sulfuric acid (SO ₄ ^2- ) content is determined by carbon and sulfur content (CO ₃ ^2- and SO ₄ ^2- sulfate, respectively) measured with a carbon sulfur analyzer, model LECO CS-300. Is converted to

  For other elements, if the element content is higher than 0.1% by mass, it is determined by X-ray fluorescence spectroscopy; if the element content is less than 0.1% by mass, the Vista AX model (sold by Varian) Determined by ICP (inductively coupled plasma).

Ignition loss is determined by measuring the loss of product mass after calcination of the product at 1000 ° C. for 1 hour.

Specific surface area and mesopore and micropore volume measurements Texture properties are determined by physisorption / desorption of N ₂ at -196 ° C. according to the Nova 2000 model sold by Quantachrome. The sample is first desorbed in a vacuum at 250 ° C. for 2 hours in the case of a calcined powder or a calcined solid material, and desorbed at 100 ° C. for 2 hours in the case of an unfired powder. The specific surface area is calculated by the BET method (Brunauer-Emmet-Teller) described in Journal of the American Chemical Society 60 (1938), pages 309-316.

  The mesopore and micropore volume, and the mesopore and micropore size distribution were measured using the BJH method [EP Barrett, LGJoyner, PHHalenda, J. Am. Chem. Soc., 73 (1951), page 373. ] Is determined.

Determination of the geometric specific surface area A _{sg The} geometric specific surface area of the powder or substance particles is determined from observations made by scanning electron microscopy SEM. The geometric specific surface area A _sg is given by equation (1):

Where ρ _i is the theoretical density of the material of particle i (determined by the penetration of helium), and d _i and D _i are “between ends” along an axis that passes through the center of gravity of particle i, respectively. The minimum and maximum dimensions of the particle i measured in (1), n is the number of particles that are to be measured, and n> 200. For agglomerated particles, n refers to the number of agglomerated particles and not the number of base particles that make them up.

Macropore Volume Measurement Macropore volume and macropore size distribution are determined by mercury porosimetry with a Porosizer 9320 model sold by Micromeritics. The sample is introduced in the form of a formed powder or solid. At a maximum applied pressure of 6000 psi, it becomes possible to measure porosity for pore sizes greater than 50 nm.

Determination of crystal structure (XRD analysis)
Powder X-ray diffraction images are obtained on a Bruker D5005 diffraction spectrometer using copper Kα radiation (1.54060Å). Intensity data is recorded at 2θ intervals between 3 and 80 °, with increments of 0.02 ° and as a one second count time per increment.

  The crystal structure can be confirmed by other well-known methods such as Raman spectroscopy or locally by transmission electron microscopy with respect to the base particles.

Determination of the particle size distribution of the particles The particle size distribution of the particles is determined by a Sedigraph X-ray transmission particle size distribution measurement method with a Sedigraph 5100 model machine sold by Micrometrics. The sample to be characterized is suspended in a solution containing sodium metaphosphate and then dispersed twice for 3 minutes under ultrasound (power 70 W). The suspension is then introduced into the analytical device with stirring.

(Detailed explanation)
One embodiment of the method according to the invention, including the steps a) to e) described above, will now be described in detail.

Step a)
In step a), the polar solvent [1] may be selected from water, alcohols, organic solvents and mixtures thereof. Preferably, the polar solvent is water.

The first reagent [2] is selected such that Zr ⁴⁺ and / or Hf ⁴⁺ ions are provided.

  Preferably, the reagent is soluble in the mother liquor solvent.

More preferably, the reagent is
-Salts of zirconium and / or hafnium that are soluble in the solvent, such as chloride, oxychloride, sulfate, oxynitrate, acetate, formate, or citrate;
-Zirconium and / or hafnium alkoxides, such as butoxide or propoxide;
-Derivatives of zirconium and / or hafnium that are soluble in acidic media in the solvent, such as basic carbonates and hydroxides;
-And their mixtures may be selected.

  Preferably, the first reagent is from a solvent soluble zirconium and / or hafnium salt and mixtures thereof, preferably from oxychloride and oxynitrate and mixtures thereof, more preferably from oxychloride. Selected.

The second reagent is a hydrolysable, preferably anisotropic, zirconium and / or hafnium derivative by precipitation with Zr ⁴⁺ and / or Hf ⁴⁺ ions provided by the first reagent, step b ) Is selected to provide an anionic group.

The second reagent [3] is preferably selected so as to provide the anionic group SO ₄ ²⁻ or PO ₄ ³⁻ , and mixtures thereof. Preferably, the second reagent may be a mixture of Na ₂ SO ₄ and H ₂ SO ₄ . Preferably, the second reagent is selected such that a SO ₄ ^2- anionic group is provided. In the first reagent providing Zr ⁴⁺ ions, the second reagent providing SO ₄ ^2- or PO ₄ ^3- anionic groups is respectively ZBS (zirconium basic sulfate) after step b). Or a zirconium basic phosphate. Even if step c) is not present, this reagent can be used after Zd or zirconium basic phosphate, step d), followed by ZHO (zirconium hydrate) or doped ZHO particles. Can bring. These reagents, ZHO or doped been ZHO or ZBS or doped been ZBS or zirconium basic phosphate or doped been zirconium basic steps e ₁ firing phosphate) or hydrothermal treatment e ₂₎ of, In some cases, zirconia or doped zirconia particles can also be provided.

In certain embodiments, the first reagent can provide both Zr ⁴⁺ and / or HF ⁴⁺ ions and anionic groups. For example, the first reagent may be zirconium sulfate, Zr (SO ₄ ) ₂ , allowing the provision of both Zr ⁴⁺ ions and SO ₄ ²⁻ anionic groups.

The ratio of the concentration of anionic groups to the concentration of Zr ⁴⁺ and / or Hf ⁴⁺ ions is preferably between 0.2 and 5. Preferably, this ratio is greater than 0.3, preferably greater than 0.4, more preferably greater than 0.5, and / or less than 2, preferably less than 1.5, more preferably less than 1.2. For example, the ratio of the concentration of SO ₄ ^2- anionic groups to the concentration of Zr ⁴⁺ ions may be between 0.3 and 2, preferably between 0.4 and 1.5, more preferably between 0.5 and 1.2. .

  The mother liquor should have a pH of 7 or less, preferably 6 or less, preferably 4 or less, preferably 2 or less. The pH adjustment of the mother liquor may be performed in particular by adding organic or inorganic acids and / or bases.

Additive [4] allows modification of the morphology and is selected from the following group:
-Anionic surfactants and mixtures thereof, in particular
○ carboxylate (Formula _{^{R-CO 2 - -G +,}} R is an aliphatic, aromatic or carbon-based chain alkyl aromatics,, G ⁺ is a single atom or polyatomic cations and / or such positive a mixture of ions), preferably ethoxylated carboxylates, ethoxylated or propoxylated fatty acid, and wherein _{RC (O) N (CH 3} ) CH 2 COO - sarcosinate, and carboxylate selected from mixtures thereof ;
O Sulfate (formula R-SO ₃ ^-- G ⁺ , R is an aliphatic, aromatic or alkylaromatic carbon-based chain, G ⁺ is a mono- or polyatomic cation and / or such cation A sulfate selected from alkyl sulfates, alkyl ether sulfates, or alkoxylated fatty alcohol sulfates, nonyl phenyl ether sulfates, and mixtures thereof;
O Sulfonate (formula R-OSO ₃ ^-- G ⁺ , R is an aliphatic, aromatic, and / or alkyl aromatic carbon-based chain, G ⁺ is a mono- or polyatomic cation and / or such A mixture of cations), preferably alkyl aryl sulfonates including dodecyl benzene sulfonate and tetrapropyl benzene sulfonate, α-sulfonated olefins, sulfonated fatty acids and fatty acid esters, sodium sulfosuccinate and sulfosuccinate, sulfosuccinate Sulfonates selected from mono- and diesters of acids, sulfosuccinic monoamides, N-acyl amino acids and N-acyl proteins, N-acylaminoalkyl sulfonates and taurinates, and mixtures thereof;
O Phosphate (formula R '-(RO) _n PO _4-n ^(3-n) --(3-n) G ⁺ , R and R' are carbon based on aliphatic, aromatic and / or alkyl aromatic G ⁺ is a mono- or polyatomic cation and / or a mixture of such cations, preferably selected from H ⁺ , Na ⁺ , and K ⁺ , and n is an integer of 3 or less ), Preferably phosphates selected from mono- and diesters of phosphoric acid, and mixtures thereof;
-Amphoteric surfactants and mixtures thereof, in particular
○ the formula RR'NH-CH ₃ COO ^- a betaine, R and R 'are aliphatic, aromatic, and / or an alkyl aromatic carbon-based chain of;
O Sulfobetaine;
O imidazolium salt;
-Cationic surfactants and mixtures thereof, in particular
O Non-quaternary ammonium compounds (formula R′-R _n NH _(4-n) ⁺ -X ⁻ , where R and R ′ are aliphatic, aromatic and / or alkyl aromatic carbon-based chains, X ^- is a mixture of single atoms or polyatomic anion and / or such anions, n represents a less than 4 integer);
○ quaternary ammonium salt (formula _{^{R'-R 4 N + -X -}} , R and R 'are aliphatic, aromatic, and / or an alkyl aromatic carbon-based chain of, X ^- represents a single atom or a multi Atomic anions and / or mixtures of such anions), preferably alkyltrimethylammonium and alkylbenzyldimethylammonium, and mixtures thereof;
O amine salts;
O Ethoxylated fatty amine ammonium salt;
O dialkyldimethylammonium;
O imidazolinium salt;
-Carboxylic acids, their salts, and mixtures thereof, especially aliphatic monocarboxylic or dicarboxylic acids, especially saturated acids; fatty acids, especially saturated fatty acids; formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, capryl Acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, hydroxystearic acid, 2-ethylhexanoic acid, behenic acid, nonyl acid, linolenic acid, abietic acid, oleic acid, lesinolic acid, naphthenic acid, phenylacetic acid Dicarboxylic acids including oxalic acid, maleic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. These acid salts may be used. The term `` carboxylate '' means a compound of formula (R-COO ⁻ , G ⁺ ), where G ⁺ is a cationic group, preferably Na ⁺ or NH ⁴⁺ ;
A nonionic surfactant selected from the set of compounds of formula RCO ₂ R ′ and R-CONHR ′, and mixtures thereof, wherein R and R ′ are aliphatic, aromatic, and / or alkyl aromatic Family carbon-based chains, especially
O Polyethoxylated and polypropoxylated fatty acid mono and diethanolamides;
O Polyethoxylated and polypropoxylated fatty amines;
O Polyethoxylated and polypropoxylated block copolymers, such as the Pluronic® series of copolymers sold by the company BASF;
○ carboxy selected from methyl fatty alcohol ethoxylates are polyethoxylated and polypropoxylated fatty alcohols and alkylphenols, this family has the formula R1-O- (CR2R3-CR4R5- O) of _n -CH ₂ -COOH , Comprising a set of ethoxylated or propoxylated fatty alcohols containing the group --CH ₂ --COOH at the end of the chain, wherein R1, R2, R3, R4, and R5 are aliphatic, aromatic, and / or alkylaromatic A carbon-based chain, where n is an integer;
O amine oxides;
O alkyl imidazolines;
○ and mixtures thereof;
-And mixtures thereof.

Additives for modifying the morphology are preferably selected from the following group:
-Anionic surfactants and mixtures thereof, in particular
○ carboxylate (Formula _{^{R-CO 2 - -G +,}} R is an aliphatic, aromatic or carbon-based chain alkyl aromatics,, G ⁺ is a single atom or polyatomic cations and / or such positive a mixture of ions), preferably ethoxylated carboxylates, ethoxylated or propoxylated fatty acid, and wherein _{RC (O) N (CH 3} ) CH 2 COO - sarcosinate, and carboxylate selected from mixtures thereof ;
O Sulfate (formula R-SO ₃ ^-- G ⁺ , R is an aliphatic, aromatic or alkylaromatic carbon-based chain, G ⁺ is a mono- or polyatomic cation and / or such cation A sulfate selected from alkyl sulfates, alkyl ether sulfates, or sulfates of ethoxylated fatty alcohols, nonyl phenyl ether sulfates, and mixtures thereof;
O Sulfonate (formula R-OSO ₃ ^-- G ⁺ , R is an aliphatic, aromatic, and / or alkyl aromatic carbon-based chain, G ⁺ is a mono- or polyatomic cation and / or such A mixture of cations), preferably alkyl aryl sulfonates including dodecyl benzene sulfonate and tetrapropyl benzene sulfonate, α-sulfonated olefins, sulfonated fatty acids and fatty acid esters, sodium sulfosuccinate and sulfosuccinate, sulfosuccinate Sulfonates selected from mono- and diesters of acids, sulfosuccinic monoamides, N-acyl amino acids and N-acyl proteins, N-acylaminoalkyl sulfonates and taurinates, and mixtures thereof;
O Phosphate (formula R '-(RO) _n PO _4-n ^(3-n) --(3-n) G ⁺ , R and R' are carbon based on aliphatic, aromatic and / or alkyl aromatic G ⁺ is a mono- or polyatomic cation and / or a mixture of such cations, preferably selected from H ⁺ , Na ⁺ , and K ⁺ , and n is an integer of 3 or less ), Preferably phosphates selected from mono- and diesters of phosphoric acid, and mixtures thereof;
-Cationic surfactants and mixtures thereof, in particular
O Non-quaternary ammonium compounds (formula R′-R _n NH _(4-n) ⁺ -X ⁻ , where R and R ′ are aliphatic, aromatic and / or alkyl aromatic carbon-based chains, X ^- is a mixture of single atoms or polyatomic anion and / or such anions, n represents a less than 4 integer);
○ quaternary ammonium salt (formula _{^{R'-R 4 N + -X -}} , R and R 'are aliphatic, aromatic, and / or an alkyl aromatic carbon-based chain of, X ^- represents a single atom or a multi Atomic anions and / or mixtures of such anions), preferably alkyltrimethylammonium and alkylbenzyldimethylammonium, and mixtures thereof;
O amine salts;
O Ethoxylated fatty amine ammonium salt;
O dialkyldimethylammonium;
○ Imidazolinium salt.

Preferably, the additive for modifying the form is selected from the following group:
-Anionic surfactants and mixtures thereof, in particular
O Sulfate (formula R-SO ₃ ^-- G ⁺ , R is an aliphatic, aromatic or alkylaromatic carbon-based chain, G ⁺ is a mono- or polyatomic cation and / or such cation A sulfate selected from alkyl sulfates, alkyl ether sulfates, or sulfates of ethoxylated fatty alcohols, nonyl phenyl ether sulfates, and mixtures thereof;
O Phosphate (formula R '-(RO) _n PO _4-n ^(3-n) --(3-n) G ⁺ , R and R' are carbon based on aliphatic, aromatic and / or alkyl aromatic G ⁺ is a mono- or polyatomic cation and / or a mixture of such cations, preferably selected from H ⁺ , Na ⁺ , and K ⁺ , and n is an integer of 3 or less ), Preferably phosphates selected from mono- and diesters of phosphoric acid, and mixtures thereof;
-Cationic surfactants and mixtures thereof, in particular
O Non-quaternary ammonium compounds (formula R′-R _n NH _(4-n) ⁺ -X ⁻ , where R and R ′ are aliphatic, aromatic and / or alkyl aromatic carbon-based chains, X ^- is a mixture of single atoms or polyatomic anion and / or such anions, n represents a less than 4 integer);
○ quaternary ammonium salt (formula ^{_{R'-R 4 N + -X -}} , R and R 'are aliphatic, aromatic, and / or an alkyl aromatic carbon-based chain of, X ^- represents a single atom or a multi Atomic anions and / or mixtures of such anions), preferably alkyltrimethylammonium and alkylbenzyldimethylammonium, and mixtures thereof.

  Additives selected from anionic and / or cationic surfactants advantageously make it possible to increase the proportion of particles of anisotropic primary derivatives after step b).

More preferably, the additive for modifying the form is selected from the following group:
-Alkyl sulfates, such as sodium dodecyl sulfate or SDS;
-Non-quaternary ammonium compounds (formula R′-R _n NH _(4-n) ⁺ -X ⁻ , R and R ′ are aliphatic, aromatic and / or alkylaromatic carbon-based chains, X ^- is a mixture of single atoms or polyatomic anion and / or such anions, n represents a less than 4 integer), for example, cetyltrimethylammonium bromide or CTAB.

In addition to additives for modifying the morphology, nonionic surfactants [5] other than those described as being able to act as additives may be added. This surfactant differs from additive [4] in that it is not possible without the additive to modify the morphology of the resulting particles. However, when combined with additives, the effects of the additives can be corrected. A simple test makes it possible to check whether the nonionic surfactant modifies the morphology of the produced particles. The optional surfactant may in particular be selected from the set of compounds of the formula R—OR ′, R—OH, R— (CH ₂ —CH ₂ —O) _n —R ′, a family of polyols, R and R ′ are aliphatic, aromatic, and / or alkyl aromatic carbon-based chains, and n is an integer.

The optional nonionic surfactant is preferably
-Polyethoxylated and polypropoxylated nonylphenol (e.g. Triton® series sold by the company Dow Chemicals);
-Polyethoxylated and polypropoxylated fatty alcohols;
-Polyethoxylated and polypropoxylated octylphenol;
-Polyethoxylated and polypropoxylated fatty acid esters;
-Polyethoxylated and polypropoxylated fatty alcohols and alkylphenols, in particular polyethoxylated and polypropoxylated ethylene glycol, propylene glycol, glycerol, polyglyceryl esters and derivatives thereof, and polyethylene glycol;
-Polyethoxylated and polypropoxylated anhydrous sorbitol esters, including sorbitan esters, and sorbitan esters or sorbates;
-Alkyl polyglucosides;
-Ethoxylated and propoxylated oils;
-And selected from their mixtures.

  An optional nonionic surfactant may be, for example, an antifoam or surface tension agent, such as Contraspum K1012 sold by the company Zschimmer-Schwartz. Such antifoams advantageously facilitate the performance of the process and / or increase its yield. Surface tension agents can, for example, increase the action of additives.

  Definitions of various surfactants and examples can be found in “Les techniques de l'ingenieur”, volume K2, updated No. 52 (May 2007), Tensioactifs K342.

The pore-forming agent [6] is in particular
-From the latex family, in particular from styrene acrylate and / or polymethyl acrylate, and from polyvinyl propionate and / or acetate;
-Polyethylene and / or polypropylene oxide and salts;
-And their mixtures may be selected.

  The addition of pore former advantageously results in the creation of porosity in the particles obtained after step b), c), d) or e). For this reason, a step of heating these particles may be necessary to remove the pore former so that space is left in the pores.

  Preferably, the amount of pore former is greater than 0.5%, preferably greater than 2% and / or less than 25%, preferably less than 10%, this percentage being the first reagent of the mother liquor Mass percentage relative to

To obtain anisotropic particles, the additive is preferably provided before the second reagent provides an anionic group and the first reagent provides Zr ⁴⁺ and / or Hf ⁴⁺ ions. It is introduced into the mother liquor immediately before or after.

  If the mother liquor contains a “separate” nonionic surfactant (ie component [5]) and / or a pore former, these agents are preferably immediately prior to the introduction of the second reagent. Thus, preferably after the introduction of the first reagent and additives, it is introduced into the mother liquor.

  By not following this order, certain additives may not be able to precipitate anisotropic particles. For example, in sodium dodecyl sulfate (SDS) used as an additive, anisotropic particles of the primary derivative of zirconium and / or hafnium are introduced immediately before or immediately after the first reagent, and It will be obtained if the second reagent is introduced before it is introduced into the mother liquor. The order of introduction of the various constituents of the mother liquor is, for example, the introduction of the polar solvent, the introduction of the first reagent, the introduction of the additive SDS, the “other” “optional” nonionic surfactant (component [ 5)), a pore-forming agent, and then a second reagent. In contrast, isotropic particles of the primary derivatives of zirconium and / or hafnium are used when this additive is introduced after the second reagent and before the first reagent is introduced into the mother liquor. Will be obtained.

  However, for some additives, the above order is not absolutely necessary. A normal test makes it possible to evaluate the influence of the component introduction sequence.

  The temperature at which the mother liquor is prepared is preferably 50 ° C. from the solidification temperature of the mother liquor solvent at atmospheric pressure so as to facilitate the dissolution of the various components introduced into the mother liquor solvent without the precipitation reaction of the starting particles. Between room temperature, conventionally between 20 ° C. and 50 ° C., preferably between 40 ° C. and 50 ° C. After all the reagents have been introduced into the mother liquor, the coagulation temperature of the mother liquor solvent at atmospheric pressure is between 50 ° C., preferably between room temperature and 50 ° C., preferably between 40 ° C. and 50 ° C., preferably at least It is maintained for 15 minutes, which advantageously allows better dissolution of the reagents and also allows to achieve good thermal and chemical homogeneity.

Step b)
In step b), the heating temperature is preferably above 50 ° C. and / or below the boiling point, preferably below 100 ° C., preferably below 95 ° C., preferably below 90 ° C., preferably below 80 ° C., or even 70 It is less than ℃. The duration maintained at temperature Δt may be greater than 30 minutes, or even greater than 1 hour, and / or preferably less than 10 hours, or even less than 5 hours.

  The present inventors have found that when the maintenance at 100 ° C. exceeds 10 hours, the resulting particle morphology is isotropic.

  Heating is preferably performed at atmospheric pressure.

  The temperature rise rate v should not be too fast to promote anisotropic growth. Preferably it is less than 50 ° C./min, preferably less than 10 ° C./min. The start of the heating phase is defined as the moment when heating of the mother liquor is started after all components have been introduced.

  At the end of step b), a final operation selected from filtration, washing, acid-base neutralization, drying, and combinations of these techniques may optionally be applied. Any technique known to those skilled in the art may be used. When drying, the optional step of deagglomeration may be performed via any technique known to those skilled in the art.

The solubility of the compound obtained after step b) depends on several parameters. In particular, in order to obtain a primary derivative having a solubility in water measured at 20 ° C. of less than 10 ⁻³ mol / l, it is preferred that the following conditions are satisfied:
The concentration of H ⁺ ions in the mother liquor is preferably between 0.6 and 3 mol / l;
The molar ratio between the concentration of anionic groups in the mother liquor and the concentration of Zr ⁴⁺ and / or Hf ⁴⁺ ions is preferably between 0.3 and 2;
The heating temperature of the mother liquor is preferably between 55 and 100 ° C.

  The Nouveau Traite de Chimie Minerale from Paul Pascal, volume IX, pages 599-610, provides a detailed description for modifying solubility.

  Thus, after step b), a suspension of particles or a suspension of powder of particles can be obtained, and after drying it is insoluble in the polar solvent [1] and can be hydrolyzed. These particles are amorphous as described below, except where optional dopants are added.

  Anisotropic particles can also be obtained. Where appropriate, routine testing allows for the search for such particles, as described above.

Step c)
Step c) is optional or necessary depending on whether it is desired to produce secondary derivatives that are slightly soluble or soluble in acidic media in polar solvents [1], respectively. . A derivative is considered slightly soluble if its solubility in water at a pH equal to 2 is less than 10 ⁻³ mol / l. In contrast, the derivative is considered soluble.

In step c), the primary derivative obtained at the end of step b) is partly or wholly, preferably entirely, anionic groups provided by the second reagent “anionic” Treatments for substitution with other anionic groups known as `` substituents '' may be carried out, which substituents have a powerful ability to form complexes with zirconium and / or hafnium, preferably One selected from oxoanions, group 17 (halide) anions, organic molecules containing carboxylate groups (R—COO ⁻ ), and mixtures thereof. More preferably, the oxo anion is selected from phosphates, sulfates, and carbonates; the halides are selected from chlorides and fluorides; Selected from.

  To perform the substitution, the primary derivative particles are placed in contact with a compound capable of providing an anionic substituent.

  In step c), the treatment of the primary derivative is carried out, for example by carbonation, phosphorylation, fluorination, respectively, so that zirconium and / or hafnium and carbonate, phosphate, fluoride or chloride anionic groups combine. Or a chlorination treatment.

  For example, after obtaining anisotropic ZBS at the end of step b), it may optionally be converted to anisotropic zirconium basic carbonate (ZBC) via carbonation treatment or phosphorylation treatment. May be converted into an anisotropic zirconium basic phosphate. The same reasoning can be applied when starting with zirconium basic phosphate. Step c) thus makes it possible to obtain compounds that are not obtainable in step b), for example because they are soluble in polar solvents [1] in acidic media.

  In step c), this process does not modify the optionally anisotropic nature of the particles obtained in step b).

  At the end of step c), a final operation selected from filtration, washing, acid-base neutralization, drying, and combinations of these techniques may optionally be applied. Any technique known to those skilled in the art may be used. When drying, an optional deagglomerate forming step may be performed via any technique known to those skilled in the art.

Step d)
Step d) of basic hydrolysis allows reaction with the primary derivative obtained after step b) or the secondary derivative obtained after step c) and also hydrates zirconium and / or hafnium. It is possible to convert it into a thing. This reaction in particular makes it possible to generate porosity within the particles.

  Any technique known to the person skilled in the art can be used to carry out the basic hydrolysis step d).

Basic hydrolysis, the primary or secondary derivative, a hydroxide anion OH ^- at least one source of, preferably a strong base, especially a NaOH or KOH, or is contacted with at least one amine by placing, the anion of the derivative OH ^- are performed for the purpose of substituting.

Primary or secondary derivatives are in particular
-Powder, or
-Obtained directly in step b) or c) or, especially after filtration, washing and / or drying performed at the end of step b) or c), resuspended in a polar solvent, preferably in water It can take the form of a suspension obtained later.

The arrangement in the contact state is, for example,
-Place the primary or secondary derivative solid powder in contact with the liquid basic solution,
-Place the solid base in contact with the liquid suspension of the primary or secondary derivative,
-Place the liquid basic solution in contact with the liquid suspension of the primary or secondary derivative,
-Arrange a gaseous base such as ammonia in contact with a liquid suspension of the primary or secondary derivative,
It can be obtained by placing a gaseous form of a base, for example ammonia, in contact with a solid powder of a primary or secondary derivative.

If the primary or secondary derivative is suspended in solution, the following conditions will preferably be used:
^-The concentration of Zr ⁴⁺ and / or Hf ^{4+ in} said solution: preferably less than 10 mol / l and greater than 0.01 mol /;
-pH: preferably above 11;
-Reaction temperature: above the solidification temperature of the solvent, preferably above room temperature, more preferably above about 50 ° C, and below the boiling point of the solvent, preferably below 90 ° C.

If suspensions of primary or secondary derivative used is mother liquor, the hydroxide anion OH ^- introduction of the (one or more) source is preferably carried out at a temperature below 90 ° C..

  At the end of step d), a final operation selected from filtration, washing, acid-base neutralization, drying, and combinations of these techniques may optionally be applied. Any technique known to those skilled in the art may be used. When drying, the optional deagglomeration step may be performed via any technique known to those skilled in the art.

Step e)
In step e1), the firing conditions modify the porosity index I _p and the specific surface area of the powder. The calcination temperature may in particular be higher than 400 ° C. and / or lower than 1200 ° C., preferably lower than 1100 ° C., more preferably lower than 1000 ° C. At temperatures above 1200 ° C., the resulting particles have a low porosity index, ie the particles are dense. At temperatures below 1200 ° C., the resulting particles are porous if the maintenance time at the stationary stage is limited. The maintenance time at the stationary stage is generally between 1 and 5 hours, preferably about 2 hours.

  The invention also relates to dense or porous particles obtained after step e1).

In step e2), hydrothermal treatment modifies the porosity index I _p and the specific surface area of the powder. The hydrothermal treatment temperature is higher than the boiling point of the polar solvent at the pressure under consideration, preferably water, preferably higher than 130 ° C and / or lower than 250 ° C, preferably lower than 200 ° C. At temperatures above 250 ° C., the resulting particles have a low porosity index, ie the particles are dense. At temperatures below 250 ° C., the resulting particles are porous.

The hydrothermal treatment may be performed by heating the powder of the primary or secondary derivative, hydrate, or oxide in the presence of water vapor, the derivative, hydrate, or oxide being optional It has been doped with. This process is specifically
-Use of undried powders of primary or secondary derivatives, or hydrates,
-It may be done by using a liquid suspension of primary or secondary derivatives, hydrates or oxides.

When the primary or secondary derivative, hydrate, or oxide powder is suspended in solution, the following conditions are preferred:
^-The concentration of Zr ⁴⁺ and / or Hf ^{4+ in} the whole suspension: preferably below 10 mol / l and above 0.01 mol / l;
-pH: preferably between 6 and 8;
-Reaction temperature: preferably above 130 ° C and / or below 250 ° C, preferably below 200 ° C;
-Duration to maintain at that temperature: preferably more than 1 hour and preferably less than 10 hours.

  For example, the hydrothermal treatment applied to the primary or secondary derivative of the present invention allows for the production of optionally porous, anisotropic zirconia. If the derivative is doped, the resulting zirconia will also be doped.

  When hydrothermal treatment is applied to a primary or secondary derivative, it can result in another primary or secondary derivative, hydrate, or oxide.

  When hydrothermal treatment is applied to a hydrate or oxide, it can result in a hydrate or oxide.

  The invention also relates to dense or porous particles obtained after step e2).

Calcination or hydrothermal treatment is doped with novel crystalline anisotropic forms, in particular oxides of elements selected from yttrium Y, lanthanum La, cerium Ce, scandium Sc, calcium Ca, magnesium Mg, and mixtures thereof Zirconium oxide and / or hafnium oxide particles, the dopant oxide having zirconium oxide and / or hafnium oxide, or selected from Si, Al, S, and mixtures thereof It is a solid solution having particles of zirconium oxide and / or hafnium oxide doped with an elemental oxide, and the dopant oxide is dispersed in the oxide particles of zirconium and / or hafnium. These particles are optionally porous when the starting particles are porous. Step e) is, for example, oxy zirconium sulfate by calcination or by hydrothermal treatment of ZBS (crystalline, anisotropic, porous), yttrium hydration as for example, allows the production of ZrOSO _4, or intimate molecular mixture By calcination or hydrothermal treatment of the doped zirconium hydrate, it is possible to produce zirconia doped with solid solution yttrium oxide.

  The above rules allow those skilled in the art to find suitable particles for a particular application, especially anisotropic particles, by simple routine tests. Where appropriate, the following experimental design can be used.

Thus after step e) the following steps can be performed:
f) Optionally, the particle powder obtained after the previous step is
-A minimum percentage of particles having an acceptable size range comprised in the range 50nm-200μm; and
-Minimum percentage of anisotropic particles; and
-Optionally performing a first test for compatibility, which allows checking, in particular, whether it has a porosity index greater than 2;
g) If the suitability test is negative, i.e. if the powders do not match, repeat the previous steps while modifying the manufacturing conditions.

The conformity test in step f) is for example
-If the number of particles is more than 20%, or even more than 50, or even more than 80%, or even more than 90%, or even more than 95% in anisotropic form, and
-If the number of particles exceeds 50%, or even more than 80%, or even more than 90%, has a size within the acceptable size range,
It can be considered positive.

  These criteria can be used especially if step d) is not performed.

To find the porous particles, the suitability test in step f)
-If the number of particles exceeds 20%, or even more than 50%, or even more than 80%, or even more than 90%, or even more than 95% have an anisotropic morphology, and
-If more than 50%, or even more than 80%, or even more than 90% of the number of particles have a size within an acceptable size range, and
-If the porosity index Ip is greater than 2,
It can be considered positive.

These criteria should be used especially when a basic hydrolysis step (step d)), or even a calcination step (step e ₁ )), or a further hydrothermal treatment step (step e ₂ )) Can do.

  Modification of the basic hydrolysis and / or calcination and / or hydrothermal treatment conditions also makes it possible to change the porosity index. An increase in pH during basic hydrolysis results in an increase in porosity index Ip. During calcination and / or hydrothermal treatment, the index Ip decreases as the heating temperature increases and / or as the maintenance time in the steady phase increases.

  Regardless of the suitability test used in step f), the lower limit of the acceptable size range may in particular be 100 nm, 150 nm, or even 200 nm, and / or the upper limit of the acceptable size range is In particular, it may be 80 μm.

In step g), if the particles do not match, the new synthesis conditions are in particular:
-During step a)
O the nature of the additive; and / or o the concentration of the additive, wherein the concentration increment is preferably greater than 5% of the initial concentration and / or less than 15% of the initial concentration, e.g. 10% of the initial concentration. Concentration; and / or ○ the order of introduction of the various constituents of the mother liquor into the solvent, in particular by introducing additives before the second reagent and immediately before or after the first reagent and / or ○ pH , In particular by setting a value lower than 2; and / or ○ the amount of anionic groups and the Zr ⁴⁺ and Hf ⁴⁺ ions whose increment is preferably greater than 0.3 and / or less than 0.6, eg 0.4 Ratio with the amount of; and / or
-During step b)
O Heating temperature, preferably below 15 ° C and / or above 5 ° C, for example by a temperature increment of 10 ° C; and / or ○ Duration to maintain at temperature Δt, preferably above 20 minutes and / or 40 minutes Less than, e.g., by a time increment of 30 minutes; and / or ○ by increasing the heating temperature increase rate v, preferably lower than 50 ° C / min and then decreasing it in increments of 5 ° C / min; and / or
-During step d)
O Heating temperature, preferably below 15 ° C and / or above 5 ° C, for example by a temperature increment of 10 ° C; and / or o By setting the pH preferably to a value higher than 11, and / or
-During step e ₁ )
O by setting the heating temperature, preferably below 1200 ° C; and / or o the duration of maintaining the temperature Δt, preferably more than 20 minutes and / or less than 40 minutes, for example 30 minutes By increment; and / or
-During step e ₂ )
O By setting the heating temperature, preferably below 250 ° C, or below 200 ° C; and / or o The duration of maintaining the temperature Δt, preferably more than 20 minutes and / or 40 minutes Less than, for example, by a 30 minute time increment
It can be determined by correction.

  The term “incremental” means a positive or negative change in a parameter.

We have discovered and recommended the following rules:
-In order to increase the maximum particle size, in step a) the acidity of the mother liquor and / or the ratio of the amount of anionic groups to the amount of Zr ⁴⁺ and Hf ⁴⁺ ions and / or the content of additives And / or in step b) it is preferred to increase the heating temperature and / or the duration maintained at that temperature;
-To reduce the sphericity index, in step a), increase the acidity of the mother liquor and / or the ratio of the amount of anionic groups to the amount of Zr ⁴⁺ and Hf ⁴⁺ ions, and / or Or in step b), it is preferable to reduce the heating temperature;
-To promote the aggregation of the base particles, in step a) reduce the acidity of the mother liquor and / or the ratio of the amount of anionic groups to the amount of Zr ⁴⁺ and Hf ⁴⁺ ions, and / or Or in step b), it is preferable to extend the duration maintained at that temperature;
-In order to increase the specific surface area of the particles, in step a) the content of additives is increased and / or in step d) the basic hydrolysis temperature is increased and / or in step e ₁ ) It is preferable to lower the calcination temperature and / or lower the hydrothermal treatment temperature in step e ₂ ). This is similar to increasing the volume of mesopores and / or micropores;
-In order to increase the yield, i.e. the amount of solid substance precipitated, in step a) the acidity is reduced and / or the amount of anionic groups lying between 0.5 and 1.2 and Zr4 ⁺ and Hf Select the ratio to the amount of ⁴⁺ ions and / or increase the content of additives and / or increase the heating temperature and / or extend the duration to maintain at that temperature in step b) Is preferred.

The particle morphology and sphericity index are modified by the values of the various parameters defined above. We have discovered and recommended the following rules:
^-The needle is adjusted so that the ratio of the amount of anionic groups, e.g. SO ₄ ^{2- and} the amount of Zr ⁴⁺ and / or Hf ⁴⁺ ions is increased and / or the content of additives is increased. By modifying the generated synthesis parameters, the amount of needles relative to the amount of isotropic particles is increased during subsequent synthesis;
-The amount of platelets relative to the amount of isotropic particles is adjusted to the subsequent amount by modifying the parameters of the synthesis that produced the platelets so as to increase the acidity of the mother liquor and / or the duration maintained at the stationary stage. Increased during synthesis;
^-Create stars so that the ratio of the amount of anionic groups such as SO ₄ ^{2- and} the amount of Zr ⁴⁺ and / or Hf ⁴⁺ ions in the mother liquor and / or the additive content increases By modifying the synthesis parameters, the amount of stars relative to the amount of isotropic particles is increased during subsequent synthesis;
-By modifying the parameters of the synthesis that produced archin so that the acidity and / or additive content of the mother liquor is increased, the amount of archin relative to the amount of isotropic particles is increased during subsequent synthesis. ;
-Hollow spheres to increase the ratio of the amount of anionic groups such as SO ₄ ^{2- and} the amount of Zr ⁴⁺ and / or Hf ⁴⁺ ions in the mother liquor and / or the acidity of the mother liquor By modifying the parameters of the generated synthesis, the amount of hollow spheres relative to the amount of isotropic particles increases during subsequent synthesis;
^-Generate leaflets so that the ratio of the amount of anionic groups such as SO ₄ ^{2- and} the amount of Zr ⁴⁺ and / or Hf ⁴⁺ ions in the mother liquor and / or the content of additives increases By modifying the synthesis parameters, the amount of leaflets relative to the amount of isotropic particles increases during subsequent synthesis;
-The needle is made finer during subsequent synthesis by modifying the parameters of the synthesis that produced the needle so that the content of additives in the mother liquor is reduced;
^-Generate needles to increase the ratio of the amount of anionic groups, for example SO ₄ ^{2- and} the amount of Zr ⁴⁺ and / or Hf ⁴⁺ ions, and / or the acidity of the mother liquor in the mother liquor By modifying the parameters of the synthesis, the amount of stars increased during subsequent synthesis and the two forms probably coexisted during the transition;
-The amount of archin is increased during subsequent synthesis by modifying the parameters of the synthesis that produced the needle so that the acidity of the mother liquor is increased and / or the content of additives in the mother liquor is decreased And two forms probably coexist during the transition;
-By modifying the parameters of the synthesis that produced the needle to increase the acidity of the mother liquor and / or the duration that it maintains at the temperature of the mother liquor, the amount of hollow spheres increased, and during the transition two kinds of Forms probably coexist;
-By modifying the parameters of the synthesis that produced the archin so as to increase the acidity of the mother liquor and / or the duration that it maintains at the temperature of the mother liquor, the amount of hollow spheres is increased and Forms probably coexist;
-By modifying the parameters of the synthesis that produced the platelets so that the additive content in the mother liquor is increased, the amount of leaflets increases and the two forms probably coexist during the transition.

  In one embodiment, the parameters of steps a) and b) are determined such that anisotropic particles of the primary derivative are obtained after step b).

The table below summarizes the preferred conditions of steps a) and b) to obtain a large number of particles having a particular morphology. In the first column, “ ^* ” indicates a main parameter.

  The order in which the components are introduced into the mother liquor is the preferred order described above.

  The rules and previous conditions are not limited according to the preferred embodiment of the present invention. These rules and conditions allow the examples described below to produce a powder suitable for a particular application.

In addition, known methods applied to currently available products allow us to make the following observations:
-Precipitation of basic solutions or hydrolysis of derivatives known in the prior art results in isotropic forms in the hydrates produced, whether or not surfactants are present;
-Hydrothermal treatment of suspensions or solutions of isotropic particles at temperatures above 200 ° C, or even above 250 ° C, is dense, crystalline, optionally anisotropic particles Resulting in a powder. This type of hydrothermal treatment is described, for example, in the paper `` Morphology of zirconia synthesized hydrothermally from zirconium oxychloride '', Journal of the American Ceramic Society, 1992, 75, 9, 2515-2519;
-Hydrothermal treatment at temperatures below 200 ° C results in a powder of isotropic particles. This type of treatment is described, for example, in the paper `` Nucleation and growth for synthesis of nanometric zirconia particles by forced hydrolysis '', Journal of Colloid and Interface Science, 1998, 198, 87-99;
-Combustion of metal salts, oxidation of metals, or high temperature firing of precursors results in a dense, optionally anisotropic particle powder.

  The method steps described so far may be modified to dope the manufactured particles. One dopant or several dopants may be introduced into one or more steps by techniques known to those skilled in the art:

Step a)
In step a), group 17 (halide) element compound, group 1 (alkali metal) element compound, yttrium Y, scandium Sc, lanthanide, alkaline earth metal (second column of the periodic table of elements) Elements), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium A dopant A selected from Nb, gallium Ga, tin Sn, and lead Pb compounds and mixtures thereof may optionally be added to the mother liquor.

  The compound may be, for example, an oxide, hydrate, salt, carbide, nitride, or metal.

The yttrium compound may be, for example, an yttrium salt, such as the salt YCl ₃ .

  Preferably, dopant A is selected from oxides, hydrates and salts, more preferably from salts.

When the dopant A is a compound of sulfur S and / or phosphorus P, and mixtures thereof, this compound is preferably SO ₄ ^2- and / or PO ₄ ^3- , preferably via a second reagent. Introduced.

  When the dopant A is an aluminum Al compound, this compound is preferably selected from aluminum hydrate.

  When the dopant A is a silicon Si compound, silicon oxide is preferred.

  More preferably, dopant A is soluble in an acidic medium.

  The dopant A is preferably a group 17 (halide) element compound, a group 1 (alkali metal) element compound, yttrium Y, scandium Sc, lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, calcium Ca, Magnesium Mg, barium Ba, strontium Sr, titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe , Manganese Mn, niobium Nb, gallium Ga, tin Sn, lead Pb, and mixtures thereof, preferably a group 17 (halide) element compound, a group 1 (alkali metal) element compound Yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, phosphorus P, aluminum Al compound, and Selected from these mixtures. More preferably, the dopant A is chlorine Cl, fluorine F, sodium Na, potassium K, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, phosphorus P, and aluminum Al. Or a mixture thereof. Preferably, finally, dopant A is selected from compounds of yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, and aluminum Al, and mixtures thereof.

Then, after step b), the resulting primary derivative becomes the primary derivative of doped zirconium and / or hafnium. For example, if in step a) the stock solution contains zirconium oxychloride, water, an additive for modifying the morphology, a second reagent for introducing SO ₄ ^2- anionic groups, and the yttrium salt YCl ₃ The primary derivative obtained after step b) becomes zirconium basic sulfate doped with yttrium basic sulfate.

  In certain preferred embodiments, dopant A is added during step a).

Step b)
In step b), an optionally doped particle suspension of the primary derivative, or a powder of optionally doped particles of the primary derivative, followed by a group 17 (halide) elemental compound , Group 1 (alkali metal) elemental compounds, yttrium Y, scandium Sc, lanthanides, alkaline earth metals (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, aluminum Al, tungsten W, Selected from chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, and lead Pb compounds and mixtures thereof Dopant B may optionally be added to the mother liquor.

  The compound may be, for example, an oxide, hydrate, salt, carbide, nitride, or metal.

The yttrium compound may be, for example, an yttrium salt, such as the salt YCl ₃ .

  Preferably, dopant B is selected from oxides, hydrates and salts, more preferably from salts.

  When the dopant B is a compound of aluminum Al, this compound is preferably selected from aluminum hydrate.

  When the dopant B is a compound of silicon Si, this compound is preferably silicon oxide.

  The dopant B is preferably a group 17 (halide) element compound, a group 1 (alkali metal) element compound, yttrium Y, scandium Sc, lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, calcium Ca, Magnesium Mg, barium Ba, strontium Sr, titanium Ti, silicon Si, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb , Gallium Ga, tin Sn, or lead Pb compounds, and mixtures thereof, preferably a group 17 (halide) element compound, a group 1 (alkali metal) element compound, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, and aluminum Al compounds, and mixtures thereof It is selected. More preferably, the dopant B is a compound of chlorine Cl, fluorine F, sodium Na, potassium K, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, and aluminum Al, and their Selected from mixtures. Preferably, finally, the dopant B is selected from compounds of yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, and aluminum Al, and mixtures thereof.

  Then, after step b), the resulting primary derivative becomes the primary derivative of doped zirconium and / or hafnium.

  Dopant B or a successor material of dopant B can be combined with the primary derivative via any method known to those skilled in the art, for example via impregnation or via coprecipitation after resuspension. Good.

  The addition of dopant A in step a) does not interfere with the addition of dopant B in step b), and vice versa.

Step c)
In step c), optionally, for the primary derivative of zirconium and / or hafnium, the anionic group of said primary derivative provided by the second reagent is complexed with zirconium and / or hafnium. Before carrying out the treatment aimed at substituting with other anionic groups having a powerful force to form a group 17 (halide) element compound, group 1 (alkali metal) element compound and , Yttrium Y, scandium Sc, lanthanide, alkaline earth metals (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, Dopan selected from compounds of vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, and lead Pb, and mixtures thereof The C1, may be used optionally to dope the primary derivative.

  The compound may be, for example, an oxide, hydrate, salt, carbide, nitride, or metal.

The yttrium compound may be, for example, an yttrium salt, such as the salt YCl ₃ .

  Preferably, the dopant C1 is selected from oxides, hydrates and salts, more preferably from salts.

When the dopant C1 is a compound of sulfur S and / or phosphorus P, and mixtures thereof, this compound is preferably SO ₄ ^2- and / or PO ₄ ^3- , preferably by a second reagent It is introduced via a compound capable of ensuring the substitution of the provided anionic group.

  When the dopant C1 is an aluminum Al compound, this compound is preferably selected from aluminum hydrate.

  When the dopant C1 is a silicon Si compound, this compound is preferably silicon oxide.

  The dopant C1 is preferably a group 17 (halide) element compound, a group 1 (alkali metal) element compound, yttrium Y, scandium Sc, lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, calcium Ca, Magnesium Mg, barium Ba, strontium Sr, titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe Selected from compounds of manganese Mn, niobium Nb, gallium Ga, tin Sn, and lead Pb, and mixtures thereof, preferably a group 17 (halide) element compound, a group 1 (alkali metal) element Compound, Yttrium Y, Scandium Sc, Lanthanum La, Cerium Ce, Calcium Ca, Magnesium Mg, Silicon Si, Sulfur S, Phosphorus P, and Aluminum Al Objects, and mixtures thereof. More preferably, the dopant C1 is chlorine Cl, fluorine F, sodium Na, potassium K, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, phosphorus P, and aluminum Al. Or a mixture thereof. Preferably, finally, the dopant C1 is selected from compounds of yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, and aluminum Al, and mixtures thereof.

  Then after step c), the secondary derivative obtained becomes a secondary derivative of doped zirconium and / or hafnium.

  The addition of dopant A in step a) and / or the addition of dopant B in step b) does not interfere with the addition of dopant C1 in step c) and vice versa.

  At the end of step c), the optional but optionally doped secondary derivative is added to a group 17 (halide) elemental compound and a group 1 (alkali metal) elemental compound. Yttrium Y, scandium Sc, lanthanide, alkaline earth metals (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo , Vanadium V, Antimony Sb, Nickel Ni, Copper Cu, Zinc Zn, Iron Fe, Manganese Mn, Niobium Nb, Gallium Ga, Tin Sn, Lead Pb, Cobalt Co, Ruthenium Ru, Rhodium Rh, Palladium Pd, Silver Ag, Osmium A dopant C2 selected from a compound of Os, iridium Ir, platinum Pt, and gold Au and mixtures thereof may be doped; preferably, the dopant C2 is a compound of a group 17 (halide) element, 1 Family (alkaline gold (Genus) element compounds, yttrium Y, scandium Sc, lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, calcium Ca, magnesium Mg, barium Ba, strontium Sr, titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, lead Pb, cobalt Co, ruthenium Ru, Selected from compounds of rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au, and mixtures thereof. More preferably, the dopant C2 is a group 17 (halide) element compound, a group 1 (alkali metal) element compound, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, Selected from compounds of silicon Si, sulfur S, phosphorus P, and aluminum Al, and mixtures thereof. Preferably, the dopant C2 is chlorine Cl, fluorine F, sodium Na, potassium K, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, phosphorus P, and aluminum Al. Selected from compounds and mixtures thereof. More preferably, the dopant C2 is selected from compounds of yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, and aluminum Al, and mixtures thereof.

Group 17 (halide) element compounds, Group 1 (alkali metal) element compounds, yttrium Y, scandium Sc, lanthanides, alkaline earth metals (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, The tin Sn and lead Pb compounds and mixtures thereof may be, for example, oxides, hydrates, salts, carbides, nitrides, or metals. The yttrium compound may be, for example, an yttrium salt, such as the salt YCl ₃ .

  Preferably, said compound is selected from oxides, hydrates and salts, more preferably from salts.

  Compounds of cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au, and mixtures thereof are, for example, oxides, hydrates, salts, or metals. There may be. The platinum compound may be, for example, a platinum salt.

  Preferably, the cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au compounds and mixtures thereof are oxides, hydrates, salts, and It is selected from metals, more specifically from metals.

  In order to dope the secondary derivative, any method known to those skilled in the art can be considered, for example, an impregnation method, and a method by coprecipitation after resuspension is considered.

  The addition of dopant A in step a) and / or the addition of dopant B in step b) and / or the use of dopant C1 in step c) does not preclude the use of dopant C2 and vice versa.

Step d)
In step d), if a doped or undoped primary or secondary derivative is suspended, yttrium Y, scandium Sc, lanthanide, alkaline earth metal (element Element in the second column of the periodic table), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, A compound based on iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, and lead Pb and a dopant D1 selected from mixtures thereof may optionally be added to the suspension.

  The compound may be, for example, an oxide, hydrate, salt, carbide, nitride, or metal.

The yttrium compound may be, for example, an yttrium salt, such as the salt YCl ₃ .

  Preferably, the dopant D1 is selected from oxides, hydrates and salts, more preferably from salts.

  More preferably, the dopant D1 is soluble in a polar solvent in which the primary or secondary derivative is suspended.

  The dopant D1 is preferably yttrium Y, scandium Sc, lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, calcium Ca, magnesium Mg, barium Ba, strontium Sr, titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, and lead Pb compounds and their More preferably, the dopant D1 is selected from compounds of yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, and aluminum Al, and mixtures thereof. The

  The dopant D1 is preferably introduced into the solvent simultaneously with the primary or secondary derivative.

  For example, if an yttrium salt is added to the suspension prior to forming the basic hydrolysis of ZBS, the resulting hydrate becomes zirconium hydrate doped with yttrium hydrate.

  Addition of dopant A in step a) and / or addition of dopant B in step b) and / or use of dopant C1 in step c) and / or dopant C2 at the end of step c) is in step d) It does not prevent the addition of dopant D1, and vice versa. In one particular embodiment, dopant A is added in step a) and dopant D1 is added in step d), which dopant A is different from dopant D1. The hydrate obtained after step d) is then co-doped, for example co-doped zirconium hydrate.

  After basic hydrolysis, optionally doped and optionally dried zirconium and hafnium hydrates, group 17 (halide) elemental compounds, group 1 (alkali metal) elemental compounds and , Yttrium Y, scandium Sc, lanthanide, alkaline earth metals (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, Vanadium V, Antimony Sb, Nickel Ni, Copper Cu, Zinc Zn, Iron Fe, Manganese Mn, Niobium Nb, Gallium Ga, Tin Sn, Lead Pb, Cobalt Co, Ruthenium Ru, Rhodium Rh, Palladium Pd, Silver Ag, Osmium Os May be doped with a dopant D2 selected from compounds of iridium Ir, platinum Pt, and gold Au, and mixtures thereof; preferably, the dopant D2 is a compound of a group 17 (halide) element , Group 1 (alkali metal) elemental compounds, yttrium Y, scandium Sc, lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, calcium Ca, magnesium Mg, barium Ba, strontium Sr, titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, lead Pb, Selected from compounds of cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au, and mixtures thereof; more preferably, the dopant D2 is a group 17 (halogen) Compound), group 1 (alkali metal) element compounds, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magne It is selected from compounds of calcium Mg, silicon Si, sulfur S, phosphorus P, and aluminum Al, and mixtures thereof. More preferably, the dopant D2 is chlorine Cl, fluorine F, sodium Na, potassium K, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, phosphorus P, and aluminum Al. And a mixture thereof. More preferably, the dopant D2 is selected from compounds of yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, and aluminum Al, and mixtures thereof.

Group 17 (halide) element compounds, Group 1 (alkali metal) element compounds, yttrium Y, scandium Sc, lanthanides, alkaline earth metals (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, The tin Sn and lead Pb compounds and mixtures thereof may be, for example, oxides, hydrates, salts, carbides, nitrides, or metals. The yttrium compound may be, for example, an yttrium salt, such as the salt YCl ₃ .

  Preferably, said compound is selected from oxides, hydrates and salts, more preferably from hydrates where appropriate.

  Compounds of cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au, and mixtures thereof are, for example, oxides, hydrates, salts, or metals. May be. The platinum compound may be, for example, a platinum salt.

  Preferably, the cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au compounds and mixtures thereof are oxides, hydrates, salts, and It is selected from metals, more specifically from metals.

  In order to dope the hydrate, any method known to those skilled in the art, such as impregnation, co-precipitation after resuspension may be used.

  This dope operation may be performed several times.

  Addition of dopant A in step a) and / or addition of dopant B in step b) and / or use of dopant C1 in step c) and / or use of dopant C2 at the end of step c) and / or Alternatively, the addition of dopant D1 before basic hydrolysis does not preclude the use of dopant D2 after basic hydrolysis, and vice versa.

Step e)
In step e), prior to calcining the derivative obtained at the end of step b) or c) or the hydrate obtained at the end of step d), the compound of the element of group 17 (halide) and , Group 1 (alkali metal) element compounds, yttrium Y, scandium Sc, lanthanides, alkaline earth metals (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, sulfur S, phosphorus P, Aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, lead Pb, cobalt Co, ruthenium Ru A compound of rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au; optionally doped to a derivative or hydrate with a dopant E1 selected from a mixture thereof May be used.

  The dopant E1 is preferably a group 17 (halide) element compound, a group 1 (alkali metal) element compound, yttrium Y, scandium Sc, lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, calcium. Ca, magnesium Mg, barium Ba, strontium Sr, titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, Compounds of iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, lead Pb, cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au, and those More preferably, the dopant E1 is a group 17 (halide) elemental compound, a group 1 (alkali metal) elemental compound, and yttrium Y, It is selected from compounds of scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, phosphorus P, and aluminum Al, and mixtures thereof.

  More preferably, the dopant E1 is chlorine Cl, fluorine F, sodium Na, potassium K, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, phosphorus P, and aluminum Al. And a mixture thereof. More preferably, the dopant E1 is selected from compounds of yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, and aluminum Al, and mixtures thereof.

Group 17 (halide) element compounds, Group 1 (alkali metal) element compounds, yttrium Y, scandium Sc, lanthanides, alkaline earth metals (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, The tin Sn and lead Pb compounds and mixtures thereof may be, for example, oxides, hydrates, salts, carbides, nitrides, or metals. The yttrium compound may be, for example, an yttrium salt, such as the salt YCl ₃ .

  Preferably, the compound is selected from oxides, hydrates and salts, more preferably from oxides where appropriate.

  Compounds of cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au, and mixtures thereof are, for example, oxides, hydrates, salts, or metals. There may be. The platinum compound may be, for example, a platinum salt.

  Preferably, the cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au compounds and mixtures thereof are oxides, hydrates, salts, and It is selected from metals, more specifically from metals.

  The oxide obtained after calcination becomes a doped oxide.

  The dope operation may be carried out by any technique known to the person skilled in the art, in particular by adding a powder or by impregnation using a suspension.

  Addition of dopant A in step a) and / or addition of dopant B in step b) and / or use of dopant C1 in step c) and / or use of dopant C2 at the end of step c) and / or Alternatively, the addition of dopant D1 before basic hydrolysis and / or the use of dopant D2 after basic hydrolysis does not preclude the use of dopant E1 before calcination, and vice versa.

  After the firing step, optionally doped and optionally dried zirconium and / or hafnium oxides include group 17 (halide) elemental compounds, group 1 (alkali metal) elemental compounds, Yttrium Y, scandium Sc, lanthanide, alkaline earth metal (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, lead Pb, cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, A dopant E2 selected from a compound of iridium Ir, platinum Pt, and gold Au and mixtures thereof may be doped; preferably, the dopant E2 is a group 17 (halide) elemental compound. , Yttrium Y, scandium Sc, lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, calcium Ca, magnesium Mg, barium Ba, strontium Sr, titanium Ti, silicon Si , Sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, lead Pb, cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au, and mixtures thereof; more preferably, the dopant E2 is a group 17 (Halide) elemental compound, group 1 (alkali metal) elemental compound, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, Magnesium Mg, silicon Si, sulfur S, a compound of phosphorus P, and aluminum Al, is selected from mixtures thereof. More preferably, the dopant E2 is chlorine Cl, fluorine F, sodium Na, potassium K, yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, phosphorus P, and aluminum Al. Selected from compounds and mixtures thereof. More preferably, the dopant E2 is selected from compounds of yttrium Y, scandium Sc, lanthanum La, cerium Ce, calcium Ca, magnesium Mg, silicon Si, sulfur S, and aluminum Al, and mixtures thereof.

Group 17 (halide) element compounds, Group 1 (alkali metal) element compounds, yttrium Y, scandium Sc, lanthanides, alkaline earth metals (elements in the second column of the periodic table of elements), titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, The tin Sn and lead Pb compounds and mixtures thereof may be, for example, oxides, hydrates, salts, carbides, nitrides, or metals. The yttrium compound may be, for example, an yttrium salt, such as the salt YCl ₃ .

  Preferably, said compound is selected from oxides, hydrates and salts, more preferably from salts.

  Compounds of cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au, and mixtures thereof are, for example, oxides, hydrates, salts, or metals. There may be. The platinum compound may be, for example, a platinum salt.

  Preferably, the cobalt Co, ruthenium Ru, rhodium Rh, palladium Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au compounds and mixtures thereof are oxides, hydrates, salts, and It is selected from metals, more specifically from metals.

  The oxide doping operation may be performed through any method known to those skilled in the art, for example, an impregnation method.

  Addition of dopant A in step a) and / or addition of dopant B in step b) and / or use of dopant C1 in step c) and / or use of dopant C2 at the end of step c) and / or Or the addition of dopant D1 before basic hydrolysis and / or the use of dopant D2 after basic hydrolysis and / or the use of dopant E1 before firing does not interfere with the use of dopant E2 after firing, The reverse is also true.

  In one variation of the invention, a triple doping operation of zirconia is performed by adding the first, second, and third dopants. For example, a Y-doped ZBS derivative is produced by adding an yttrium salt. Next, a Y / Ce co-doped hydrate is produced by adding a cerium salt. Finally, before firing, an aluminum salt is added so that zirconia doped with Y / Ce / Al is obtained.

  In general, the use of one dopant can be made independent of the use of one or more other dopants.

  However, the dopant may be of type A and / or C1 and / or D1 and / or E1 in order to locate the dopant within a particle that takes the form of a defined compound, solid solution, or intimate molecular mixture. preferable. The dopant is preferably of type B and / or C2 and / or D2 and / or E2 in order to locate the dopant within the particle in the form of a dispersion or inclusion or on the surface of the particle. .

  The molar amount of dopant in the particles may be less than 40%, less than 20%, less than 10%, or even less than 5%, or even less than 3%.

(Example)
The following examples are given for illustrative purposes and do not limit the invention.

(Comparative Example 1)
Powder outside the scope of the present invention 110 g of zirconium oxychloride was dissolved in 300 ml of deionized water in a 1 l Pyrex beaker with stirring, then 28 g of sodium sulfate was added, and deionized water was added to this mixture. Make 500ml. The acidity of the mother liquor is 1.2, the concentration of (Zr ⁴⁺ + Hf ⁴⁺ ) is 0.6 mol / l, and the molar ratio of the anionic group SO ₄ ^2- to (Zr ⁴⁺ + Hf ⁴⁺ ) Is 0.6. After complete dissolution of the reagents, the solution is brought to 90 ° C. with a heating gradient of 1 ° C./min with continued stirring. The solution is maintained at 90 ° C for 1 hour and then cooled to below 50 ° C.

  This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium basic sulfate ZBS.

The powder thus obtained has a specific surface area of 3 m ² / g and is amorphous according to X-ray diffraction. ZBS particles have a characteristic quasi-spherical shape known as “a bunch of grapes”.

The cake is then suspended in 250 ml of deionized water in a 1 liter Teflon® PTFE beaker. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water and the pH is adjusted to 5 by adding 0.1N hydrochloric acid. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is resuspended in 1 l of deionized water and the pH is adjusted to 11 with 1N aqueous ammonia (NH ₄ OH). The suspension is then filtered and washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium hydrate or ZHO.

The powder thus obtained has a specific surface area of 320 m ² / g. The volume of mesopores and micropores is 0.18 cm ³ / g, and the powder is amorphous by X-ray diffraction. ZHO particles are quasi-spherical similar to that of the starting ZBS derivative.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 500 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 60 m ² / g; the sum of the volume of mesopores and micropores is 0.12 cm ³ / g; the powder is determined by X-ray diffraction Thus, it is crystalline in the form of a mixture of tetragonal and monoclinic phases. Zirconia particles are quasi-spherical similar to the case of ZBS derivatives (shown in FIG. 3a) and ZHO initial particles.

(Example 2)
Needle-form powder 210 g of zirconium oxychloride is dissolved in 300 ml of deionized water in a 1 l Pyrex beaker with stirring at 50 ° C., after which sodium dodecyl sulfate or 2.5 g of SDS is added, then 52 g of sodium sulfate Add, bring the mixture to 500 ml with deionized water, adjust the temperature to 50 ° C. and maintain for 15 minutes after all reagents have dissolved. The acidity of the mother liquor is 2, the concentration of (Zr ⁴⁺ + Hf ⁴⁺ ) is 1 mol / l, and the molar ratio of the anionic group SO ₄ ^2- to (Zr ⁴⁺ + Hf ⁴⁺ ) Is 0.6 and the concentration of SDS additive is 0.02 mol / l. It is observed that bubbles are present on the surface of the solution. The solution is then brought to 70 ° C. with a heating ramp of 1 ° C./min with continued stirring. The solution is maintained at 70 ° C for 15 minutes and then cooled to below 50 ° C.

  This procedure produces a suspension also formed from the solid phase and liquid supernatant and foam. The suspension is filtered off and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium basic sulfate ZBS.

The ZBS powder thus obtained has a specific surface area of 6 m ² / g and is amorphous according to X-ray diffraction. The ZBS particles are in the form of needles having a length L between 0.5 and 3 μm, a width l between 0.3 and 0.8 μm, and a thickness e between 0.25 and 0.8 μm. For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l.

The cake is then suspended in 250 ml of deionized water in a 1 liter Teflon® PTFE beaker. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water and the pH is adjusted to 5 by adding 0.1N hydrochloric acid. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is resuspended in 1 l of deionized water and the pH is adjusted to 11 by adding 1N aqueous ammonia (NH ₄ OH). The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium hydrate or ZHO.

The powder thus obtained has a specific surface area of 360 m ² / g and is amorphous according to X-ray diffraction. The total volume of mesopores and micropores is 0.25 cm ³ / g. ZHO particles are in the form of needles with a length L between 0.5 and 3 μm, a width l between 0.3 and 0.8 μm, and a thickness e between 0.25 and 0.8 μm, in the case of the starting ZBS derivative It is similar. For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 500 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 120 m ² / g, the total volume of mesopores and micropores is 0.20 cm ³ / g, the powder is determined by X-ray diffraction As such, it is crystalline in the form of a mixture of square and monoclinic phases. The zirconia particles are in the form of needles with a length L between 1 and 2 μm, a width l between 0.3 and 0.8 μm, and a thickness e between 0.25 and 0.8 μm, and ZBS derivatives (see FIG. Similar to the initial particles of ZHO). For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l.

(Example 3)
Needle shaped powder
In a 1 liter Pyrex beaker, 110 g of zirconium oxychloride is dissolved in 300 ml of deionized water with stirring at 50 ° C., then 20 g of cetyltrimethylammonium bromide or CTAB is added, followed by 42 g of sodium sulfate. The mixture is made up to 500 ml with deionized water. Adjust temperature to 50 ° C. and maintain for 15 minutes after all reagents have dissolved. The acidity of the mother liquor is 1.2, the concentration of (Zr ⁴⁺ + Hf ⁴⁺ ) is 0.6 mol / l, and the molar ratio of the anionic group SO ₄ ^2- to (Zr ⁴⁺ + Hf ⁴⁺ ) Is 0.9 and the concentration of the CTAB additive is 0.1 mol / l. It is observed that bubbles are present on the surface of the solution. The solution is then brought to 60 ° C. with a heating ramp of 1 ° C./min with continued stirring. The solution is maintained at 60 ° C for 30 minutes and then cooled to below 50 ° C.

  This procedure produces a suspension also formed from the solid phase and liquid supernatant and foam. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium basic sulfate ZBS.

The ZBS powder thus obtained has a specific surface area of 3 m ² / g and is amorphous according to X-ray diffraction. The ZBS particles are in the form of needles with a length L between 20 and 40 μm, a width l between 2 and 5 μm and a thickness e between 1.5 and 5 μm. For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l.

The cake is then suspended in 250 ml of deionized water in a 1 liter Teflon® PTFE beaker. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water and the pH is adjusted to 5 by adding 0.1N hydrochloric acid. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is resuspended in 1 l of deionized water and the pH is adjusted to 11 by adding 1N aqueous ammonia (NH ₄ OH). The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium hydrate or ZHO.

The powder thus obtained has a specific surface area of 350 m ² / g and the sum of the volume of mesopores and micropores is 0.20 cm ³ / g. Amorphous. ZHO particles are in the form of needles having a length L between 20 and 40 μm, a width l between 2 and 5 μm, and a thickness e between 1.5 and 5 μm. For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l. The needle is similar to that of the starting ZBS derivative.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 500 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 100 m ² / g, the total volume of mesopores and micropores is 0.18 cm ³ / g, the powder is determined by X-ray diffraction Is crystalline as a mixture of square and monoclinic phases. The zirconia particles are in the form of needles having a length L between 15 and 30 μm, a width l between 1 and 4 μm, and a thickness e between 0.7 and 4 μm. For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l. The needle is similar to that of the initial ZBS derivative (shown in FIG. 3c) and ZHO.

(Example 4)
Star shaped powder
In a 1 liter Pyrex beaker, 110 g of zirconium oxychloride is dissolved in 300 ml of deionized water with stirring at 50 ° C., then 5 g of cetyltrimethylammonium bromide or CTAB is added, followed by 50 ml of 36% HCl HCl. Then 28 g of sodium sulfate are added and the mixture is made up to 500 ml with deionized water. Adjust temperature to 50 ° C. and maintain for 15 minutes after all reagents have dissolved. The acidity of the mother liquor is 2.4, the concentration of (Zr ⁴⁺ + Hf ⁴⁺ ) is 0.6 mol / l, and the molar ratio of the anionic group SO ₄ ^2- to (Zr ⁴⁺ + Hf ⁴⁺ ) Is 0.6 and the concentration of additive CTAB is 0.025 mol / l. It is observed that bubbles are present on the surface of the solution. The solution is then brought to 60 ° C. with a heating ramp of 1 ° C./min with continued stirring. The solution is maintained at 60 ° C for 1 hour and then cooled to below 50 ° C.

  This procedure produces a suspension also formed from the solid phase and liquid supernatant and foam. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium basic sulfate ZBS.

The ZBS powder thus obtained has a specific surface area of 3 m ² / g and is amorphous according to X-ray diffraction. ZBS particles are star-shaped with a length between 5 and 40 μm.

The cake is then suspended in 250 ml of deionized water in a 1 liter Teflon® PTFE beaker. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water and the pH is adjusted to 5 by adding 0.1N hydrochloric acid. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is resuspended in 1 l of deionized water and the pH is adjusted to 11 by adding 1N aqueous ammonia (NH ₄ OH). The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is then formed from zirconium hydrate or ZHO.

The powder thus obtained has a specific surface area of 340 m ² / g, the sum of the volume of mesopores and micropores is 0.20 cm ³ / g, this powder is according to X-ray diffraction Amorphous. ZHO particles have a star shape between 5 and 40 μm in length, similar to that of the starting ZBS derivative.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 500 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 90 m ² / g, the total volume of mesopores and micropores is 0.18 cm ³ / g, the powder is determined by X-ray diffraction As such, it is crystalline in the form of a mixture of square and monoclinic phases. Zirconia particles have a star shape between 5 and 30 μm in length, similar to the case of ZBS (shown in FIG. 3d) and ZHO derivative initial particles.

  As shown in FIG. 3d, the needle forming the ZBS star has a tapered pointed shape. These needles are substantially cylindrical around their long axis. Their cross-sectional surface area, which is substantially disc-shaped, gradually decreases toward the tip (s). Furthermore, the lateral outer surface of the needle is particularly smooth. ZHO and zirconia needles have similar shapes.

(Example 5)
Archin shaped powder
In a 1 liter Pyrex beaker, 110 g of zirconium oxychloride is dissolved in 300 ml of deionized water with stirring at 50 ° C., then 0.5 g of cetyltrimethylammonium bromide or CTAB is added, followed by 28 g of sodium sulfate. The mixture is made up to 500 ml with deionized water. Adjust temperature to 50 ° C. and maintain for 15 minutes after all reagents have dissolved. The acidity of the mother liquor is 1.2, the concentration of (Zr ⁴⁺ + Hf ⁴⁺ ) is 0.6 mol / l, and the molar ratio of the anionic group SO ₄ ^2- to (Zr ⁴⁺ + Hf ⁴⁺ ) Is 0.6, and the concentration of the additive CTAB is 0.0025 mol / l. It is observed that bubbles are present on the surface of the solution. The solution is then brought to 60 ° C. with a heating ramp of 1 ° C./min with continued stirring. The solution is maintained at 60 ° C for 1 hour and then cooled to below 50 ° C.

  This procedure produces a suspension also formed from the solid phase and liquid supernatant and foam. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium basic sulfate ZBS.

The ZBS powder thus obtained has a specific surface area of 6 m ² / g and is amorphous according to X-ray diffraction. ZBS particles are in the form of aggregates having a size between 10 and 30 μm, formed from needle and star shaped particles with a length L of 2 μm.

The cake is then suspended in 250 ml of deionized water in a 1 liter Teflon® PTFE beaker. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water and the pH is adjusted to 5 by adding 0.1N hydrochloric acid. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is resuspended in 1 l of deionized water and the pH is adjusted to 11 by adding 1N aqueous ammonia (NH ₄ OH). The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium hydrate or ZHO.

The powder thus obtained has a specific surface area of 360 m ² / g, the total volume of mesopores and micropores is 0.25 cm ³ / g, and the powder is amorphous by X-ray diffraction It is. ZHO particles take the form of agglomerates that are formed from 2 μm particles in the form of needles and stars, with a maximum dimension of 10 to 30 μm, similar to that of the starting ZBS derivative.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 500 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 120 m ² / g, the total volume of mesopores and micropores is 0.21 cm ³ / g, the powder is determined by X-ray diffraction As such, it is crystalline in the form of a mixture of square and monoclinic phases. Zirconia particles are in the form of aggregates between 5 and 20 μm in maximum dimension formed from 1 μm particles in the form of needles and stars, similar to the case of ZBS derivatives (shown in Figure 3e) and ZHO initial particles. ing.

(Example 6)
Powder in the shape of a platelet
In a 1 liter Pyrex beaker, 110 g of zirconium oxychloride is dissolved in 300 ml of deionized water with stirring at 50 ° C., then 5 g of cetyltrimethylammonium bromide or CTAB is added, then 25 ml of 36% HCl HCl is added, Then 28 g of sodium sulfate are added and the mixture is made up to 500 ml with deionized water. Adjust temperature to 50 ° C. and maintain for 15 minutes after all reagents have dissolved. The acidity of the mother liquor is 2, the concentration of (Zr ⁴⁺ + Hf ⁴⁺ ) is 0.6 mol / l, and the molar ratio of the anionic group SO ₄ ^2- to (Zr ⁴⁺ + Hf ⁴⁺ ) Is 0.6 and the concentration of additive CTAB is 0.025 mol / l. It is observed that bubbles are present on the surface of the solution. The solution is then brought to 60 ° C. with a heating ramp of 1 ° C./min with continued stirring. The solution is maintained at 60 ° C for 1 hour and then cooled to below 50 ° C.

  This procedure produces a suspension also formed from the solid phase and liquid supernatant and foam. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium basic sulfate ZBS.

The ZBS thus obtained has a specific surface area of 3 m ² / g and is amorphous according to X-ray diffraction. ZBS particles are about 50% quasi-spherical particles known as “a bunch of grapes” and have a thickness e between 1 and 3 μm, a length L between 10 and 20 μm and a width l between 10 and 15 μm. It is in the form of a mixture with 50% platelets between. For each of these platelets, L / l is less than 1.5.

The cake is then suspended in 250 ml of deionized water in a 1 liter Teflon® PTFE beaker. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water and the pH is adjusted to 5 by adding 0.1N hydrochloric acid. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is resuspended in 1 l of deionized water and the pH is adjusted to 11 by adding 1N aqueous ammonia (NH ₄ OH). The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium hydrate or ZHO.

The powder thus obtained has a specific surface area of 340 m ² / g, the total volume of mesopores and micropores is 0.22 cm ³ / g, and the powder is amorphous by X-ray diffraction It is. ZHO particles consist of about 50% quasi-spherical particles known as “a bunch of grapes”, a thickness e between 1 and 3 μm, a length L between 10 and 20 μm and a width l between 10 and 15 μm. It takes the form of a mixture with 50% platelets in between. For each of these platelets, L / l is less than 1.5.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 500 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 80 m ² / g, the total volume of mesopores and micropores is 0.15 cm ³ / g, the powder is determined by X-ray diffraction As such, it is crystalline in the form of a mixture of square and monoclinic phases. Zirconia particles are about 50% quasi-spherical particles known as “a bunch of grapes” and have a thickness e between 1 and 2 μm, a length L between 8 and 15 μm and a width l between 8 and 12 μm. It takes the form of a mixture with 50% platelets in between. This form is similar to the case of ZBS derivatives (shown in FIG. 3f) and ZHO initial particles. For each of these platelets, L / l is less than 1.5.

(Example 7)
Powder in the form of a hollow sphere
In a 1 l Pyrex beaker, 55 g of zirconium oxychloride is dissolved in 300 ml of deionized water with stirring at 50 ° C., then 2.5 g of cetyltrimethylammonium bromide or CTAB is added, followed by 25 ml of 36% HCl HCl. Then 7 g of sodium sulfate are added, the mixture is made up to 500 ml with deionized water, the temperature is adjusted to 50 ° C. and maintained for 15 minutes after all the reagents have dissolved. The acidity of the mother liquor is 1.2, the concentration of (Zr ⁴⁺ + Hf ⁴⁺ ) is 0.3 mol / l, and the molar ratio of the anionic group SO ₄ ^2- to (Zr ⁴⁺ + Hf ⁴⁺ ) Is 0.4, and the concentration of the additive CTAB is 0.015 mol / l. It is observed that bubbles are present on the surface of the solution. The solution is then brought to 60 ° C. with a heating ramp of 1 ° C./min with continued stirring. The solution is maintained at 60 ° C for 1 hour and then cooled to below 50 ° C.

  This procedure produces a suspension also formed from the solid phase and liquid supernatant and foam. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium basic sulfate ZBS.

The ZBS powder thus obtained has a specific surface area of ² m ² / g and is amorphous according to X-ray diffraction. ZBS particles are about 50% quasi-spherical particles known as “a bunch of grapes” and have a sphericity index between 0.85 and 0.93, a maximum outer diameter D between 50 and 300 μm and a maximum inner diameter D ′. It takes the form of a mixture with 50% hollow spheres which are between 35 and 280 μm. The wall thickness of these spheres is between 5 and 20 μm and the ratio D / D ′ is less than 2.

The cake is then suspended in 250 ml of deionized water in a 1 liter Teflon® PTFE beaker. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water and the pH is adjusted to 5 by adding 0.1N hydrochloric acid. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is resuspended in 1 l of deionized water and the pH is adjusted to 11 by adding 1N aqueous ammonia (NH ₄ OH). The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is then formed from zirconium hydrate or ZHO.

The powder thus obtained has a specific surface area of 280 m ² / g, the sum of the volume of mesopores and micropores is 0.15 cm ³ / g, this powder is according to X-ray diffraction Amorphous. ZHO particles are about 50% quasi-spherical particles known as “a bunch of grapes”, a sphericity index between 0.85 and 0.93, a maximum outer diameter D between 50 and 300 μm, and a maximum inner diameter D ′. It takes the form of a mixture with 50% hollow spheres which are between 35 and 280 μm. The wall thickness of these spheres is between 5 and 20 μm and the ratio D / D ′ is between 1.1 and 1.5. These forms are similar to those of the starting ZBS derivative.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 500 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 60 m ² / g, the sum of the volume of mesopores and micropores is 0.10 cm ³ / g, this powder is determined by X-ray diffraction As such, it is crystalline in the form of a mixture of square and monoclinic phases. Zirconia particles consist of about 50% quasi-spherical particles known as “a bunch of grapes”, a sphericity index between 0.85 and 0.9, a maximum outer diameter D between 50 and 300 μm, and a maximum inner diameter D ′. It takes the form of a mixture with 50% hollow spheres which are between 35 and 280 μm. The wall thickness of these spheres is between 5 and 20 μm and the ratio D / D ′ is between 1.1 and 1.5. These forms are similar to the case of ZBS derivatives (shown in FIG. 3g) and ZHO initial particles.

(Example 8)
Small leaf shaped powder
In a 1 liter Pyrex beaker, 110 g of zirconium oxychloride is dissolved in 300 ml of deionized water with stirring at 50 ° C., then 100 g of cetyltrimethylammonium bromide or CTAB is added, followed by 28 g of sodium sulfate and the mixture To 500 ml with deionized water. Adjust temperature to 50 ° C. and maintain for 15 minutes after all reagents have dissolved. The acidity of the mother liquor is 1.2, the concentration of (Zr ⁴⁺ + Hf ⁴⁺ ) is 0.6 mol / l, and the molar ratio of the anionic group SO ₄ ^2- to (Zr ⁴⁺ + Hf ⁴⁺ ) Is 0.6 and the concentration of additive CTAB is 1 mol / l. It is observed that bubbles are present on the surface of the solution. The solution is then brought to 60 ° C. with a heating ramp of 1 ° C./min with continued stirring. The solution is maintained at 60 ° C for 1 hour and then cooled to below 50 ° C.

  This procedure produces a suspension also formed from the solid phase and liquid supernatant and foam. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium basic sulfate, ZBS.

The ZBS powder thus obtained has a specific surface area of 4 m ² / g and is amorphous according to X-ray diffraction. ZBS particles are about 50% quasi-spherical particles known as “a bunch of grapes” and have a thickness e between 1 and 2 μm, a length L between 10 and 20 μm and a width l between 10 and 15 μm. It takes the form of a mixture with 50% leaflets consisting of 10 to 15 platelets in between. For each of these platelets, L / l is less than 1.5.

The cake is then suspended in 250 ml of deionized water in a 1 liter Teflon® PTFE beaker. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water and the pH is adjusted to 5 by adding 0.1N hydrochloric acid. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is resuspended in 1 l of deionized water and the pH is adjusted to 11 by adding 1N aqueous ammonia (NH ₄ OH). The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium hydrate or ZHO.

The powder thus obtained has a specific surface area of 340 m ² / g and the sum of the volume of mesopores and micropores is 0.25 cm ³ / g. Amorphous. ZHO particles are about 50% quasi-spherical particles known as "a bunch of grapes" and have a thickness e between 1 and 2 μm, a length L between 10 and 20 μm and a width l between 10 and 15 μm. It takes the form of a mixture with 50% leaflets consisting of 10 to 15 platelets in between, similar to the case of the particles of the starting ZBS derivative. For each of these platelets, L / l is less than 1.5.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 500 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 100 m ² / g, the total volume of mesopores and micropores is 0.20 cm ³ / g, as determined by X-ray diffraction, It is crystalline in the form of a mixture of square and monoclinic phases. Zirconia particles are about 50% quasi-spherical particles known as “a bunch of grapes” and have a thickness e between 0.5 and 1 μm, a length L between 8 and 15 μm and a width l between 8 and 12 μm. It takes the form of a mixture with 50% leaflets consisting of 10 to 15 platelets in between. This shape is similar to the case of ZBS derivatives and ZHO initial particles. For each of these platelets, L / l is less than 1.5.

(Example 9)
Needle-shaped powder with a dopant in the form of yttrium chloride YCl ₃
In a 1 liter Teflon® PTFE beaker, 100 g of ZBS from Example 3 is suspended in 250 ml of deionized water and then 80 g of a 1 mol / l solution of yttrium chloride YCl ₃ (D1 type dopant) is added. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water, the pH is adjusted to 5 by adding 0.1N hydrochloric acid, and then 11N by adding 1N aqueous ammonia (NH ₄ OH). Adjust to. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from yttrium hydrate or ZHY doped zirconium hydrate.

Table 1b shows the main physicochemical properties of the powder thus obtained. This powder has a specific surface area of 300 m ² / g, the total volume of mesopores and micropores is 0.18 cm ³ / g, and is amorphous according to X-ray diffraction. The ZHY particles are in the form of needles with a length L between 20 and 40 μm, a width l between 2 and 5 μm and a thickness e between 1.5 and 5 μm, which is the starting ZBS derivative Similar to the case of particles. For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 800 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 50 m ² / g and the total volume of mesopores and micropores is 0.15 cm ³ / g, this powder is determined by X-ray diffraction As shown, it is a square crystal. Zirconia particles doped with 3 mol% Y ₂ O ₃ have needles with a length L between 15 and 30 μm, a width l between 1 and 4 μm and a thickness e between 0.7 and 4 μm. In shape, which is similar to the initial ZBS derivative and the initial particles of the initial ZHY. For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l.

(Example 10)
Needle-shaped powder with a dopant in the form of yttrium chloride YCl ₃
In a 1 l Teflon® PTFE beaker, 100 g of ZBS from Example 3 is suspended in 250 ml of deionized water and 220 g of a 1 mol / l solution of yttrium chloride YCl ₃ is added. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water, the pH is adjusted to 5 by adding 0.1N hydrochloric acid, and then 11N by adding 1N aqueous ammonia (NH ₄ OH). Adjust to. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from yttrium hydrate or ZHY doped zirconium hydrate.

The powder thus obtained has a specific surface area of 300 m ² / g and the sum of the volume of mesopores and micropores is 0.15 cm ³ / g, which according to X-ray diffraction Amorphous. ZHY particles are in the form of needles with a length L between 20 and 40 μm, a width l between 2 and 5 μm and a thickness e between 1.5 and 5 μm, in the case of the starting ZBS derivative It is similar. For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l.

The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The powder obtained is calcined at 800 ° C. in air for 2 hours (temperature gradient 2 ° C./min; air flow rate 100 ml / min, ie hourly space velocity HSV 300 h ⁻¹ ).

The powder thus obtained has a specific surface area of 45 m ² / g, the sum of the volume of mesopores and micropores is 0.13 cm ³ / g, this powder is determined by X-ray diffraction It is a cubic shape. Zirconia particles doped with 8 mol% Y ₂ O ₃ have needles with a length L between 15 and 30 μm, a width l between 1 and 4 μm and a thickness e between 0.7 and 4 μm. Shaped and similar to the initial particles of the initial ZBS derivative and the initial ZHY. For each of these needles, L / l is between 1.67 and 50 and the thickness e is greater than 0.5 times the width l.

(Example 11)
Star shaped powder
In a 1 l Pyrex beaker, 110 g of zirconium oxychloride is dissolved in 300 ml of deionized water with stirring at 50 ° C., then 5 g of cetyltrimethylammonium bromide or CTAB is added, followed by 50 ml of 36% HCl HCl, Then 28 g of sodium sulfate is added and the mixture is brought to 500 ml with deionized water, the temperature is adjusted to 50 ° C. and maintained for 15 minutes after all the reagents have dissolved. The acidity of the mother liquor is 2.4, the concentration of Zr ⁴⁺ and / or Hf ⁴⁺ ions is 0.6 mol / l, and the anionic group SO ₄ ^2- and Zr ⁴⁺ and / or Hf ⁴⁺ ions The molar ratio is 0.6 and the concentration of additive CTAB is 0.025 mol / l. It is observed that bubbles are present on the surface of the mother liquor. The mother liquor is then brought to 60 ° C. with a heating gradient of 1 ° C./min with continued stirring. The mother liquor is maintained at 60 ° C for 1 hour and then cooled to below 50 ° C.

  This procedure produces a suspension also formed from the solid phase and liquid supernatant and foam. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is formed from zirconium basic sulfate, ZBS.

The main physicochemical properties of the ZBS powder thus obtained are shown in the table below. This powder has a specific surface area of 3 m ² / g and is amorphous according to X-ray diffraction. ZBS particles have a star shape with dimensions between 5 and 40 μm.

The cake is then suspended in 250 ml of deionized water in a 1 liter Teflon® PTFE beaker. In a second 1 liter Teflon® PTFE beaker, 25 g of sodium hydroxide NaOH is dissolved in 250 ml of deionized water. The basic sodium hydroxide solution is then slowly added to the ZBS suspension; the pH of the final suspension is between 12-13. The suspension is then brought to 90 ° C. with a heating ramp of 1 ° C./min. The suspension is maintained at 90 ° C for 2 hours and then cooled to below 50 ° C. This procedure produces a suspension formed from the solid phase and the liquid supernatant. The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The cake thus obtained is then resuspended in 1 l of deionized water and the pH is adjusted to 5 by adding 0.1N hydrochloric acid. The suspension is then filtered and then washed with 1 l of deionized water on a Buchner type filter. The resulting cake is resuspended in 1 l of deionized water and the pH is adjusted to 11 by adding 1N aqueous ammonia (NH ₄ OH). The suspension is then filtered and then washed twice with 1 l of deionized water on a Buchner type filter. The resulting cake is formed by zirconium oxyhydroxide or ZHO.

The powder thus obtained has a specific surface area of 340 m ² / g, the total volume of mesopores and micropores is 0.20 cm ³ / g and is amorphous according to X-ray diffraction. is there. ZHO particles have a maximum dimension between 5 and 40 μm, similar to that of the starting ZBS derivative.

  The resulting cake is then dried in an oven at 110 ° C. for at least 12 hours and then crushed in an agate mortar. The obtained powder is calcined at 1250 ° C. in air for 2 hours (temperature gradient 5 ° C./min, no air flow).

The powder thus obtained has a specific surface area of ² m ² / g, the sum of the volume of mesopores and micropores is equal to 0.01 cm ³ / g, this powder is determined by X-ray diffraction As shown, it is monoclinic crystalline. The zirconia particles have a star shape and their maximum dimensions are between 5 and 30 μm, similar to those of the initial ZBS derivative (shown in FIG. 3h) and the initial ZHO hydrate.

  As shown in FIG. 3h, the needles forming the zirconia stars have a tapered, straight, pointed shape. These needles are substantially cylindrical around their long axis. Their cross-sectional surface area, which is substantially disc-shaped, gradually decreases toward the tip (s). Furthermore, the lateral outer surface of the needle is particularly smooth.

  The table below shows the compositions produced and their loss on ignition for the examples.

  The table below shows the measurement results obtained for the particles of the examples.

  “P” indicates the sum of the mesopore volume and the micropore volume.

D _pores represent the average equivalent diameter of pores with dimensions less than 50 nm.

  “Single” indicates a monoclinic phase.

  “Square” indicates a square-shaped phase.

  “Cubic” indicates a cubic phase.

  As can be clearly seen here, the present invention makes it possible to produce particles formed from novel anisotropic particles or anisotropic base particles, which advantageously have a high porosity material or powder. Enables the generation of Such materials and powders are particularly useful for catalyst or filtration applications.

  Furthermore, the particles themselves formed from these anisotropic particles or anisotropic base particles may be made of a porous material, and in particular may have microporosity and / or mesoporosity. These microporosity and / or mesoporosity can be developed specifically for the catalysis of certain chemical reactions.

Claims (24)

The maximum particle size D _99.5 is less than 200 μm and the porosity index Ip is greater than 2, said porosity index being equal to the ratio A _sr / A _sg ,
A _sg is the theoretical geometric specific surface area of the powder particles;
-A _sr is a powder that is a measurement of the actual specific surface area by BET,
The powder has a sphericity index of less than 0.6 and has the formula MO _x (OH) _y (OH ₂ ) _z , where M is Zr ⁴⁺ , Hf ⁴⁺ , or a mixture of Zr ⁴⁺ and Hf ⁴⁺ , Subscripts x and z are positive or 0, subscript y is positive and 2x + y is equal to 4] zirconium and / or hafnium hydrate, doped or doped A powder comprising more than 20% of aggregated or non-agglomerated base particles formed from non-hydrated or formed as a mixture of such hydrates.   The powder according to claim 1, wherein the porosity index Ip is greater than 10.   The powder according to claim 2, wherein the porosity index Ip is greater than 50. The maximum particle size D _99.5 is less than 200 μm, all dimensions are formed from base particles larger than 50 nm, the sphericity index is less than 0.6, and the formula MO _x (OH) _y (OH ₂ ) _z [ ^Where M is Zr ⁴⁺ , Hf ⁴⁺ , or a mixture of Zr ⁴⁺ and Hf ⁴⁺ , the subscripts x and z are positive or 0, the subscript y is positive, and 2x + y is equal to 4. Zirconium and / or hafnium hydrates, formed from doped or undoped hydrates or made of mixtures of such hydrates, agglomerated or agglomerated a more include powders than 20% free base particles by the number, the powder has a specific surface area greater than ^{10 m} 2 / g, the sum of mesopore and micropore volume is 0.05 cm ³ / g Ri large, powder. 5. The powder according to claim 4, wherein the specific surface area is greater than 100 m < ² > / g and the sum of the volume of mesopores and micropores is greater than 0.10 cm < ³ > / g. 6. The powder according to claim 5, wherein the specific surface area is greater than 200 m < ² > / g and the sum of the volume of mesopores and micropores is greater than 0.20 cm < ³ > / g.   The powder according to any one of claims 1 to 6, comprising more than 90% of the base particles.   The powder according to any one of claims 1 to 7, wherein the base particles have a sphericity index greater than 0.02.   9. The powder of claim 8, wherein the base particles have a sphericity index that is greater than 0.1 and less than 0.3.   10. A powder according to any one of the preceding claims, wherein at least 80% of the number of base particles has a needle and / or platelet shape.   11. A powder according to claim 10, wherein at least 80% of the number of base particles is aggregated in the form of regular and / or irregular aggregated particles.   12. A powder according to claim 11, wherein the agglomerated particles take the form of stars comprising 3 to 15 branches.   12. A powder according to claim 11, wherein the agglomerated particles take the form of leaflets formed from 2 to 50 platelets.   A central cavity such that D / D ′ ≦ 2 when the agglomerated particles have a sphericity index greater than 0.7 and D indicates the maximum outer diameter of the particles and D ′ indicates the maximum inner diameter of the cavity The powder according to claim 11, which takes the form of hollow spheres.   15. Powder according to any one of claims 1 to 3 and 7 to 14, wherein all dimensions of the base particles and / or aggregated particles are larger than 50 nm.   16. Powder according to any one of the preceding claims, wherein all dimensions of the base particles and / or agglomerated particles are greater than 200 nm. _17. A powder according to any one of the _preceding claims, wherein the largest baked and / or agglomerated particle size D _99.5 is less than 150 _m .   The hydrate includes a group 17 element compound, a group 1 element compound, yttrium Y, scandium Sc, lanthanide, alkaline earth metal, titanium Ti, silicon Si, sulfur S, phosphorus P, aluminum Al, Tungsten W, chromium Cr, molybdenum Mo, vanadium V, antimony Sb, nickel Ni, copper Cu, zinc Zn, iron Fe, manganese Mn, niobium Nb, gallium Ga, tin Sn, lead Pb, cobalt Co, ruthenium Ru, rhodium Rh 18. Dopant is doped with a dopant selected from compounds based on palladium, Pd, silver Ag, osmium Os, iridium Ir, platinum Pt, and gold Au, and mixtures thereof. Powder. To the hydrate known as "first hydrate"
-A second hydrate of an element selected from Y, La, Ce, Sc, Ca, Mg and mixtures thereof as an intimate molecular mixture with said first hydrate;
-Aluminum hydrate dispersed in said first hydrate;
-An oxide of an element selected from Si, S, and mixtures thereof dispersed in the first hydrate;
19. A powder according to claim 18, doped with a dopant selected from-and mixtures thereof.   The powder according to claim 14 or 15, wherein the molar amount of the dopant is 20% or less. A process for the production of powders of doped and undoped zirconium and / or hafnium hydrate particles and mixtures thereof, said method comprising the steps of starting from a powder of the starting particles with the formula M (OH) _x (N ') _Y (OH ₂ ) _{z where} M is Zr ⁴⁺ , Hf ⁴⁺ , or a mixture of Zr ⁴⁺ and Hf ⁴⁺ , N ′ is an anion or a mixture of anions, and the subscripts x and y are exact And z is positive or 0] comprising basifying hydrolysis to a zirconium and / or hafnium derivative, wherein the derivative is ^10-3 has a solubility of less than mol / l, the derivative may not or doped is doped, said starting particles, sphericity index aggregates less than 0.6 Method that is formed from a base particles or non-agglomerated.   The derivative may be doped or undoped zirconium and / or hafnium basic sulfate, doped or undoped zirconium and / or hafnium basic phosphate, and doped or doped. 22. The method of claim 21, wherein the method is selected from non-zirconium basic carbonates and / or hafnium carbonates, and mixtures thereof. Zirconium and / or hafnium derivatives may be used in the following steps:
a) at least
[1] Polar solvent;
[2] a first reagent that is preferably soluble in an acidic medium in the solvent, providing Zr ⁴⁺ and / or Hf ⁴⁺ ions;
[3] a second reagent providing an anionic group;
[4] Anionic surfactant; amphoteric surfactant; cationic surfactant; carboxylic acid and its salt; formula RCO ₂ R ′ and R-CONHR ′ wherein R and R ′ are aliphatic and aromatic Nonionic surfactants selected from the group of compounds of the group consisting of aromatic and / or alkylaromatic carbon-based chains; and additives selected from the group formed by mixtures thereof;
[5] Optionally, another nonionic surfactant;
[6] optionally preparing an acidic mother liquor by mixing a pore former;
b) heating the mother liquor to ^convert Zr ⁴⁺ and / or Hf ⁴⁺ ions and anionic groups to the formula M (OH) _x (N ′) _y , known as “primary derivatives” of zirconium and / or hafnium. (OH ₂ ) _z [wherein M is a metal cation or a mixture of metal cations, N ′ is an anion or a mixture of anions, the subscripts x and y are strictly positive numbers, The letter z is a positive number or zero], and is precipitated in the form of a compound having a solubility in water below 20 ° C. of less than 10 ⁻³ mol / l and optionally drying ;
23. According to claim 21 or 22, optionally prepared by the step of c) optionally replacing said anionic group with another anionic group known as "anionic substituent" and optionally drying. The method described.   Catalyst, catalyst support, filtration element, fuel cell element, piezoelectric material, optical connector, dental ceramic, structural ceramic, comprising or obtained from the powder according to any one of claims 1 to 20 Device selected from the list.