US20190055135A1 - Method for producing an alumina gel having a high dispersibility and a specific crystallite size - Google Patents

Method for producing an alumina gel having a high dispersibility and a specific crystallite size Download PDF

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US20190055135A1
US20190055135A1 US16/072,016 US201716072016A US2019055135A1 US 20190055135 A1 US20190055135 A1 US 20190055135A1 US 201716072016 A US201716072016 A US 201716072016A US 2019055135 A1 US2019055135 A1 US 2019055135A1
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alumina gel
temperature
alumina
weight
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Malika Boualleg
Olivier LAFON
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IFP Energies Nouvelles IFPEN
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/34—Preparation of aluminium hydroxide by precipitation from solutions containing aluminium salts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/0052—Preparation of gels
    • B01J13/0056—Preparation of gels containing inorganic material and water
    • B01J13/006—Preparation of gels containing inorganic material and water by precipitation, coagulation, hydrolyse coacervation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/0052—Preparation of gels
    • B01J13/0069—Post treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/06—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04
    • B01J20/08—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04 comprising aluminium oxide or hydroxide; comprising bauxite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
    • B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
    • B28B11/243—Setting, e.g. drying, dehydrating or firing ceramic articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B3/00—Producing shaped articles from the material by using presses; Presses specially adapted therefor
    • B28B3/20—Producing shaped articles from the material by using presses; Presses specially adapted therefor wherein the material is extruded
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82B—NANOSTRUCTURES FORMED BY MANIPULATION OF INDIVIDUAL ATOMS, MOLECULES, OR LIMITED COLLECTIONS OF ATOMS OR MOLECULES AS DISCRETE UNITS; MANUFACTURE OR TREATMENT THEREOF
    • B82B3/00—Manufacture or treatment of nanostructures by manipulation of individual atoms or molecules, or limited collections of atoms or molecules as discrete units
    • B82B3/0009—Forming specific nanostructures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82B—NANOSTRUCTURES FORMED BY MANIPULATION OF INDIVIDUAL ATOMS, MOLECULES, OR LIMITED COLLECTIONS OF ATOMS OR MOLECULES AS DISCRETE UNITS; MANUFACTURE OR TREATMENT THEREOF
    • B82B3/00—Manufacture or treatment of nanostructures by manipulation of individual atoms or molecules, or limited collections of atoms or molecules as discrete units
    • B82B3/0061—Methods for manipulating nanostructures
    • B82B3/0066—Orienting nanostructures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F17/00—Compounds of rare earth metals
    • C01F17/30—Compounds containing rare earth metals and at least one element other than a rare earth metal, oxygen or hydrogen, e.g. La4S3Br6
    • C01F17/32—Compounds containing rare earth metals and at least one element other than a rare earth metal, oxygen or hydrogen, e.g. La4S3Br6 oxide or hydroxide being the only anion, e.g. NaCeO2 or MgxCayEuO
    • C01F17/34—Aluminates, e.g. YAlO3 or Y3-xGdxAl5O12
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/021—After-treatment of oxides or hydroxides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/04—Compounds with a limited amount of crystallinty, e.g. as indicated by a crystallinity index
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/60—Compounds characterised by their crystallite size
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/22—Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity

Definitions

  • the present invention relates to the preparation of alumina gels or boehmite gels.
  • the present invention relates to a process for the preparation of alumina gels, comprising a single precipitation step consisting of dissolving a specific acidic aluminium precursor, aluminium chloride, in water at a temperature in the range 10° C. to 90° C., in a manner such that the pH of the solution is in the range 0.5 to 5, for a period in the range 2 to 60 minutes, then adjusting the pH to a pH in the range 7.5 to 9.5 by adding a specific basic precursor, sodium hydroxide, to the solution obtained in order to obtain a suspension, at a temperature in the range 5° C. to 35° C., and for a period in the range 5 minutes to 5 hours, followed by a filtration step of the suspension obtained in order to obtain a precipitate, said process not comprising any washing steps after said filtration step.
  • the process in accordance with the invention can be used to obtain an alumina gel with a high dispersibility and a reduced crystallite size.
  • the present invention also relates to a novel alumina gel with a high dispersibility index, and in particular a dispersibility index of more than 80%, a crystallite dimension, obtained by the Scherrer X ray diffraction formula along the crystallographic directions [020] and [120], respectively in the range 0.5 to 10 nm and in the range 0.5 to 15 nm, as well as a chlorine content in the range 0.001% to 2% by weight and a sodium content in the range 0.001% to 2% by weight, the percentages by weight being expressed with respect to the total weight of the alumina gel.
  • the alumina gel prepared in this manner may then advantageously be shaped in order to be used as a catalyst support in many refining processes.
  • the alumina gel is shaped into the form of alumina beads, they may be used as a catalyst support in oligomerization or catalytic reforming processes.
  • the alumina beads obtained in this manner may also be used as an adsorbent.
  • the U.S. Pat. No. 4,676,928 describes a process for the production of an alumina which is dispersible in water, comprising a step for forming an aqueous dispersion of alumina, a step for adding an acid in order to produce an acidic dispersion with a pH in the range 5 to 9, a step for maturation at a high temperature of more than 70° C. for a period which is sufficient to transform the alumina into a colloidal gel, then a step for drying said colloidal gel obtained.
  • the U.S. Pat. No. 5,178,849 also describes a process for the production of an alpha alumina, comprising a step for dispersion of an aluminium hydrate with a dispersibility of less than 70%, a step for acidification of the dispersion obtained at a pH of less than 3.5 in order to at least partially dissolve the aluminium hydrate, a step for hydrothermal treatment of the acidic dispersion obtained at a temperature in the range 150° C. to 200° C., a pressure in the range 5 to 20 atm for a period in the range 0.15 to 4 hours in order to obtain a colloidal boehmite with a dispersibility of more than 90%.
  • the alumina support is prepared in accordance with a method comprising a first step for the formation of an alumina dispersion by mixing, in a controlled manner, a first aqueous alkaline solution and a first aqueous acidic solution, at least one of said acidic and basic solutions or both of them comprising an aluminium compound.
  • the acidic and basic solutions are mixed in proportions such that the pH of the resulting dispersion is in the range 8 to 11.
  • the acidic and basic solutions are also mixed in quantities which may be used to obtain a dispersion containing the desired quantity of alumina; in particular, the first step can be used to obtain 25% to 35% by weight of alumina with respect to the total quantity of alumina formed at the end of the two precipitation steps.
  • the first step is operated at a temperature in the range 20° C. to 40° C.
  • the temperature of the suspension is increased to a temperature in the range 45° C. to 70° C., then the heated suspension undergoes a second precipitation step by bringing said suspension into contact with a second aqueous alkaline solution and a second aqueous acidic solution, at least one of the two solutions or both of them comprising an aluminium compound.
  • the pH is adjusted to between 8 and 10.5 by the proportions of acidic and basic solutions which are added and the remaining quantity of alumina to be formed in the second step is supplied via the quantities of the second acidic and basic solutions which are added.
  • the second step is operated at a temperature in the range 20° C. to 40° C.
  • the alumina gel formed in this manner comprises at least 95% of boehmite.
  • the dispersibility of the alumina gel obtained in this manner is not mentioned.
  • the alumina gel is then filtered, washed and optionally dried using methods which are known to the person skilled in the art, without a prior hydrothermal treatment step, in order to produce an alumina powder which is then shaped using methods which are known to the person skilled in the art, then calcined in order to produce the final alumina support.
  • a process for the preparation of an alumina gel in a single precipitation step consisting of dissolving a specific acidic aluminium precursor, aluminium chloride, followed by adjusting the pH using a specific basic precursor, sodium hydroxide, without a subsequent co-precipitation step, results in an alumina gel which has small crystallites.
  • the preparation process in accordance with the invention can be used to obtain alumina gel or boehmite composed of crystallites the size of which, obtained by the Scherrer X ray diffraction formula along the crystallographic directions [020] and [120], are respectively in the range 0.5 to 10 nm and in the range 0.5 to 15 nm, and preferably in the range 0.5 to 2 nm and in the range 0.5 to 3 nm, and highly preferably respectively in the range 0.5 to 1.5 and in the range 0.5 to 2.5.
  • novel preparation process in accordance with the invention is also characterized by an absence of washing of the precipitate obtained at the end of the precipitation step, after filtration of said precipitate.
  • the Applicant has also discovered that employing specific operating conditions for the pH and temperatures of the precipitation step a), combined with the absence of washing of the precipitate obtained at the end of the precipitation step after filtration, not only can produce an alumina gel which has small crystals, but also can produce an alumina gel with a very high dispersibility, preferably more than 80%, and which might even reach 100%.
  • Said process in accordance with the invention can thus be used to obtain an alumina gel having a better dispersibility index compared with prior art alumina gels, thereby facilitating shaping thereof using techniques which are known to the person skilled in the art.
  • the invention concerns a process for the preparation of an alumina gel in a single precipitation step a), said precipitation step consisting of dissolving an acidic aluminium precursor, aluminium chloride, in water at a temperature in the range 10° C. to 90° C., in a manner such that the pH of the solution is in the range 0.5 to 5, for a period in the range 2 to 60 minutes, then adjusting the pH to a pH in the range 7.5 to 9.5 by adding a basic precursor, sodium hydroxide, to the solution obtained in order to obtain a suspension, at a temperature in the range 5° C.
  • One advantage of the present invention is that a preparation process is provided which can be used to obtain an alumina gel having a reduced crystallite dimension compared with alumina gels prepared in accordance with the prior art, and in particular having small crystals.
  • Another advantage of the present invention is that a process is provided for the preparation of an alumina gel which, because of the specific operating conditions employed, namely pH and the temperatures for the precipitation step a), combined with the absence of washing the precipitate obtained at the end of the precipitation step, after filtration, can not only produce an alumina gel with small crystals, but also can produce an alumina gel with a very high dispersibility, preferably more than 80% and possibly even up to 100%.
  • Another advantage of the present invention is that a process is provided for the preparation of an alumina gel with reduced crystallite dimensions, which is simplified and cheaper compared with conventional prior art alumina preparation processes such as, for example, sol-gel type preparation processes, in that the process in accordance with the invention comprises only a single precipitation step and does not comprise any steps for washing the precipitate obtained.
  • the present invention also concerns a novel alumina gel having a high dispersibility index, and in particular a dispersibility index of more than 80%, a crystallite dimension, obtained by the Scherrer X ray diffraction formula along the crystallographic directions [020] and [120], respectively in the range 0.5 to 10 nm and in the range 0.5 to 15 nm, as well as a chlorine content in the range 0.001% to 2% by weight and a sodium content in the range 0.001% to 2% by weight, the percentages by weight being expressed with respect to the total weight of the alumina gel.
  • One advantage of the invention is that a novel alumina gel is provided which has a very high dispersibility compared with alumina gels of the prior art.
  • An alumina gel characterized by a high dispersibility index will be more easily shaped using any of the shaping techniques known to the person skilled in the art such as, for example, mixing-extrusion, granulation or by the oil-drop technique, than a gel with a low dispersibility index.
  • the present invention concerns an alumina gel having a high dispersibility index, and in particular a dispersibility index of more than 80%, a crystallite dimension, obtained by the Scherrer X ray diffraction formula along the crystallographic directions [020] and [120], respectively in the range 0.5 to 10 nm and in the range 0.5 to 15 nm, as well as a chlorine content in the range 0.001% to 2% by weight and a sodium content in the range 0.001% to 2% by weight, the percentages by weight being expressed with respect to the total weight of the alumina gel.
  • the term “dispersibility index” is defined as the weight of peptised alumina gel which can be dispersed by centrifuging in a polypropylene tube at 3500 G for 3 min.
  • the dispersibility is measured by dispersing 10% of boehmite or alumina gel in a suspension of water also containing 10% of nitric acid with respect to the mass of boehmite. Next, the suspension is centrifuged at 6000 rpm for 10 min. The collected sediments are dried overnight at 100° C. then weighed.
  • DI The dispersibility index
  • Scherrer's formula is a formula used in the X ray diffraction of polycrystalline powders or samples that links the width at half height of the diffraction peaks to crystallite dimension. It is described in detail in the reference: Appl. Cryst. (1978). 11, 102-113, Scherrer after sixty years: A survey and some new results in the determination of crystallite dimension, J. I. Langford and A. J. C. Wilson.
  • the alumina gel in accordance with the invention has a dispersibility index in the range 80% to 100%, preferably in the range 85% to 100%, highly preferably in the range 88% to 100% and yet more preferably in the range 90% to 100%.
  • the alumina gel or boehmite in the form of a powder in accordance with the invention is composed of crystallites the dimensions of which, obtained by the Scherrer X ray diffraction formula along the crystallographic directions [020] and [120], are respectively in the range 0.5 to 10 nm and in the range 0.5 to 15 nm.
  • the alumina gel in accordance with the invention has a crystallite dimension in the [020] crystallographic direction in the range 0.5 to 2 nm and a crystallite dimension in the [120] crystallographic direction in the range 0.5 to 3 nm, and highly preferably respectively in the range 0.5 to 1.5 and in the range 0.5 to 2.5.
  • the alumina gel prepared in accordance with the invention has an impurities content, in particular chlorine, measured by X ray fluorescence, in the range 0.001% to 2% by weight and a sodium content, measured by ICP, or inductively coupled plasma spectrometry, in the range 0.001% to 2% by weight, the percentages by weight being expressed with respect to the total weight of the alumina gel.
  • the alumina gel prepared in accordance with the invention comprises a chlorine content in the range 0.001% to 1% by weight, preferably in the range 0.001% to 0.70% by weight, highly preferably in the range 0.003% to 0.60% by weight, and yet more preferably in the range 0.005% to 0.50% by weight.
  • the alumina gel prepared in accordance with the invention comprises a sodium content in the range 0.001% to 1% by weight, preferably in the range 0.001% to 0.80% by weight, highly preferably in the range 0.0015% to 0.60% by weight, and 0.002% to 0.050% by weight.
  • the process for the preparation of the alumina gel in accordance with the invention comprises and is preferably constituted by a single precipitation step a), said precipitation step consisting of dissolving an acidic aluminium precursor, aluminium chloride, in water at a temperature in the range 10° C. to 90° C., in a manner such that the pH of the solution is in the range 0.5 to 5, for a period in the range 2 to 60 minutes, then adjusting the pH to a pH in the range 7.5 to 9.5 by adding a basic precursor, sodium hydroxide, to the solution obtained in order to obtain a suspension, at a temperature in the range 5° C.
  • Said precipitation step consists of dissolving a specific acidic aluminium precursor, namely aluminium chloride AlCl 3 , in water, at a temperature in the range 10° C. to 90° C., preferably in the range 10° C. to 80° C., more preferably in the range 10° C. to 75° C. and most preferably in the range 15° C. to 70° C.
  • the pH of the solution obtained is in the range 0.5 to 5, preferably in the range 1 to 4, preferably in the range 1.5 to 3.5.
  • the solution is stirred for a period in the range 2 to 60 minutes, and preferably for 5 to 30 minutes and preferably in the range 5 to 10 minutes.
  • the pH of the suspension obtained is then adjusted to a pH termed the terminal precipitation pH in the range 7.5 to 9.5, preferably in the range 7.5 to 9 and more preferably in the range 7.7 to 8.8 by adding a specific basic precursor, namely sodium hydroxide, NaOH, at a temperature in the range 5° C. to 35° C., preferably in the range 10° C. to 30° C. and more preferably in the range 10° C. to 25° C. and for a period in the range 5 minutes to 5 hours, preferably in the range 10 minutes to 5 hours, preferably in the range 15 minutes to 2 hours.
  • a specific basic precursor namely sodium hydroxide, NaOH
  • Adding NaOH means that the boehmite can be precipitated and a suspension can be obtained.
  • the precipitation is carried out in the absence of an organic additive.
  • the precipitation of the alumina gel is carried out with stirring.
  • the process in accordance with the invention does not comprise a supplemental step for precipitation and does not comprise a subsequent co-precipitation step by contact, in an aqueous reaction medium, of at least one basic precursor with at least one acidic precursor, at least one of the precursors, basic or acidic, comprising aluminium.
  • an alumina gel with reduced crystallite dimensions compared with alumina gels prepared in accordance with the prior art may be obtained, and in particular an alumina gel or boehmite composed of crystallites the dimensions of which, obtained by the Scherrer X ray diffraction formula along the crystallographic directions [020] and [120], is respectively in the range 0.5 to 10 nm and in the range 0.5 to 15 nm, and preferably respectively in the range 0.5 to 2 nm and in the range 0.5 to 3 nm, and highly preferably respectively in the range 0.5 to 1.5 and in the range 0.5 to 2.5.
  • the process for the preparation of the alumina gel in accordance with the invention also comprises a filtration step b) of the suspension obtained at the end of the precipitation step in order to obtain a precipitate.
  • Said filtration step is carried out in accordance with methods which are known to the person skilled in the art.
  • the preparation process does not comprise any steps for washing the precipitate obtained at the end of the filtration step.
  • the alumina gel obtained at the end of the precipitation step, followed by a filtration step b) and without any washing steps for the precipitate obtained, may then advantageously be dried in a drying step for said precipitate obtained at the end of the filtration step in order to obtain a powder, said drying step advantageously being carried out by drying at a temperature of 100° C. or more, or by spray drying or by any other drying technique which is known to the person skilled in the art.
  • said drying step may advantageously be carried out in a closed and ventilated oven.
  • said drying step is operated at a temperature in the range 100° C. to 300° C., highly preferably at a temperature in the range 120° C. to 250° C.
  • the cake obtained at the end of the second precipitation step, followed by a filtration step is taken up into suspension.
  • Said suspension is then sprayed in fine droplets into a vertical cylindrical chamber in contact with a stream of hot air in order to evaporate the water in accordance with a principle which is well known to the skilled person.
  • the powder obtained is entrained by the flow of heat up to a cyclone or a sleeve filter which will separate the air from the powder.
  • spray drying may be carried out in accordance with the operating protocol described in the publication Asep Bayu Dani Nandiyanto, Kikuo Okuyama, Advanced Powder Technology, 22, 1-19, 2011.
  • the powder obtained at the end of the optional drying step may then advantageously be shaped in order to obtain a green material.
  • green material means the shaped material which has not undergone heat treatment steps.
  • said shaping step may be carried out by mixing-extrusion, granulation, by the oil-drop technique, or by pelletization.
  • said shaping step is carried out by mixing-extrusion or by oil-drop.
  • the green material obtained and optionally shaped may optionally then undergo a step for heat treatment at a temperature in the range 500° C. to 1000° C., for a period advantageously in the range 2 to 10 h, in the presence or absence of a stream of air containing up to 60% by volume of water.
  • said heat treatment is carried out in the presence of a stream of air containing water.
  • said heat treatment step is operated at a temperature in the range 540° C. to 850° C.
  • said heat treatment step is operated for a period in the range 2 h to 10 h.
  • Said heat treatment step enables the boehmite to be transformed into the final alumina.
  • the heat treatment step may optionally be preceded by drying at a temperature in the range 50° C. to 120° C., in accordance with any technique which is known to the person skilled in the art.
  • the process in accordance with the invention may be used to obtain an alumina gel, optionally in the powder form, having crystallites with reduced dimensions compared with alumina gels prepared in accordance with the prior art.
  • the alumina gel or boehmite obtained in the form of powder in accordance with the invention is composed of crystallites the dimension of which, obtained by the Scherrer X ray diffraction formula along the crystallographic directions [020] and [120], is respectively in the range 0.5 to 10 nm and in the range 0.5 to 15 nm and preferably respectively in the range 0.5 to 2 nm and in the range 0.5 to 3 nm, and highly preferably respectively in the range 0.5 to 1.5 and in the range 0.5 to 2.5.
  • the present invention also concerns the alumina gel which is capable of being obtained using the preparation process in accordance with the invention.
  • the productivity when producing the suspension obtained at the end of the precipitation step a) is improved by the absence of a washing step, which favours the productivity of the process (economising on water, and a much shorter time for synthesis of the boehmite than in conventional processes) in accordance with the invention, as well as an extrapolation of the process to an industrial scale.
  • the absence of washing and thus the major presence of salts on the surface of the boehmite crystallites means that an alumina gel with an improved dispersibility is obtained.
  • a commercial alumina gel powder, Pural SB3 was prepared using a sol-gel route, by hydrolysis-polycondensation of an aluminium alkoxide.
  • the chlorine content was measured using the X ray fluorescence method, and the sodium content was measured by ICP, or inductively coupled plasma spectrometry, and were below the detection limits for these measurement methods.
  • the alumina gel obtained had a very good dispersibility index but large crystallite dimensions.
  • An alumina gel was prepared in accordance with a synthesis process which was not in accordance with the invention, in that the temperature at which precipitation of the alumina gel was carried out was a temperature which was higher than 35° C.
  • a solution was prepared containing 326 mL of deionized water and 135.6 g of aluminium chloride hexahydrate (AlCl 3 .6H 2 O) at a temperature of 55° C., in a manner such as to obtain a solution with a pH of 0.5, over a period of 5 minutes.
  • AlCl 3 .6H 2 O aluminium chloride hexahydrate
  • Example 2 A sample of the precipitate obtained was removed from the reaction medium.
  • the XRD ( FIG. 1 ) of the precipitate showed that the precipitate obtained in Example 2 was in fact a precipitate of boehmite.
  • the precipitate of boehmite obtained in Example 2 was highly crystalline.
  • the size of the crystallites of boehmite obtained were measured using Scherrer's method.
  • a high precipitation temperature had resulted in an alumina gel with large crystallite dimensions and a mediocre dispersibility index.
  • An alumina gel was prepared in accordance with a synthesis process which was not in accordance with the invention, in that the pH following precipitation of the alumina gel was a pH higher than 9.5.
  • a solution was prepared containing 326 mL of deionized water and 135.6 g of aluminium chloride hexahydrate (AlCl 3 .6H 2 O) at a temperature of 20° C., in a manner such as to obtain a solution with a pH of 0.5, over a period of 5 minutes.
  • AlCl 3 .6H 2 O aluminium chloride hexahydrate
  • Example 3 A sample of the precipitate obtained was removed from the reaction medium.
  • the XRD ( FIG. 2 ) of the precipitate showed that the precipitate obtained in Example 3 was in fact a precipitate of boehmite.
  • the boehmite precipitate obtained in Example 3 was highly crystalline.
  • An alumina gel was prepared in accordance with a synthesis process which was not in accordance with the invention, in that the precipitate was washed following the filtration step.
  • a solution was prepared containing 326 mL of deionized water and 135.6 g of aluminium chloride hexahydrate (AlCl 3 .6H 2 O) at a temperature of 25° C., in a manner such as to obtain a solution with a pH of 0.5, over a period of 5 minutes.
  • AlCl 3 .6H 2 O aluminium chloride hexahydrate
  • Example 4 A sample of the precipitate obtained was removed from the reaction medium.
  • the XRD ( FIG. 3 ) of the precipitate showed that the precipitate obtained in Example 4 was in fact a precipitate of boehmite.
  • the boehmite precipitate obtained had low crystallinity.
  • the crystallites Due to the intense washing of the precipitate obtained following the precipitation step, the crystallites had a large size and the gel obtained had a mediocre dispersibility index.
  • An alumina gel was prepared in accordance with a synthesis process which was in accordance with the invention.
  • a solution was prepared containing 326 mL of deionized water and 135.6 g of aluminium chloride hexahydrate (AlCl 3 .6H 2 O) at a temperature of 25° C., in a manner such as to obtain a solution with a pH of 0.5, over a period of 5 minutes.
  • AlCl 3 .6H 2 O aluminium chloride hexahydrate
  • Example 5 A sample of the precipitate obtained was removed from the reaction medium.
  • the XRD ( FIG. 4 ) of the precipitate showed that the precipitate obtained in Example 5 was in fact a precipitate of boehmite.
  • the boehmite precipitate obtained in Example 5 was of low crystallinity.
  • the preparation process in accordance with the invention can be used to obtain a gel which is 100% dispersible and is also less expensive than in conventional prior art alumina preparation processes such as, for example, sol-gel type preparation processes using Pural SB3 as described in Example 1. Furthermore, the crystallite dimension is lower than that obtained by any other mode for the preparation of alumina gels known in the literature.

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GB2123804B (en) * 1982-06-23 1985-08-07 Grace W R & Co Dispersible alpha-aluminate monohydrate
US4676928A (en) 1986-01-30 1987-06-30 Vista Chemical Company Process for producing water dispersible alumina
SU1738326A1 (ru) * 1990-09-26 1992-06-07 Институт общей и неорганической химии АН БССР Способ получени адсорбента на основе оксида алюмини
US5178849A (en) 1991-03-22 1993-01-12 Norton Company Process for manufacturing alpha alumina from dispersible boehmite
JPH08268716A (ja) * 1995-03-30 1996-10-15 Japan Energy Corp 擬ベ−マイト粉の粒径制御方法
RU2376059C2 (ru) 2003-09-17 2009-12-20 Шелл Интернэшнл Рисерч Маатсхаппий Б.В. Способ и катализатор гидроконверсии тяжелого углеводородного исходного сырья
ES2677894T3 (es) * 2005-07-16 2018-08-07 Archroma Ip Gmbh Procedimiento para la producción de nanopartículas de óxido de aluminio y óxidos de elementos del grupo principal I y II del sistema periódico
JP5140930B2 (ja) * 2006-02-17 2013-02-13 日産自動車株式会社 金属酸化物粒子複合体、それを用いた樹脂複合材、及びそれらの製造方法
JP2013129575A (ja) * 2011-12-22 2013-07-04 Jgc Catalysts & Chemicals Ltd アルミナ微粒子、アルミナ水和物微粒子および塗料組成物
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CN108495817A (zh) 2018-09-04
RU2018130988A3 (zh) 2020-05-20
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EP3408226A1 (fr) 2018-12-05
US20200399138A1 (en) 2020-12-24
US11577964B2 (en) 2023-02-14
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WO2017129497A1 (fr) 2017-08-03
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