CN1524795A - Preparing process of zirconia - Google Patents

Abstract

The invention provides a process for preparing zirconium oxide, characterized in that the zirconates aqueous solution is mixed uniformly with alkali precipitating reagent solution, the obtained Zr(OH)4 aquagel is carried through stalling handling, filtering, scouring, and drying sintering, characterized by that, the aging treatment is done under the condition of mixing, constant pressure, 50-100 deg. C temperature return flow and constant pH=7.5-14 for 5-120 hrs, the process can be used to prepare complete tetragonal phase zirconium oxide with large specific surface.

Description

A kind of zirconic preparation method

Technical field

The invention relates to a kind of zirconic preparation method, further say so about a kind of preparation method of tetragonal phase zircite.

Background technology

Zirconium white ZrO ₂The surface have acidity, alkalescence and redox property, and have certain specific surface area and pore structure.Therefore, zirconium white can be used as acidity, alkalescence and redox catalyst.For example it in reaction such as isomerisation of olefin, alcohols dehydration, the catalytic performance that shows (Mater.Chem.PHy., 133,47,1985).

Zirconium white is the carrier use (Catal.Today, 20,199,1994) as catalyzer more, and the important field of research that zirconium white uses as carrier is the preparation super acidic catalyst.Work as ZrO ₂With sulfate radical SO ₄ ^2-In conjunction with, the SO that obtains ₄ ^2-/ ZrO ₂Be traditional solid super-strong acid, in many catalyzed reactions, show good performance (J.Am.Chem.Soc., 101 (2), 6439,1079; Catal.Rev.Sci.Eng., 38 (2), 329,1996).For example, the ZrO of platinum load ₂Catalyzer can be used for CO ₂Reforming methane prepares in the reaction of synthetic gas (DE9,400,513).

As everyone knows, the specific surface area of support of the catalyst is big more, and the catalytic active component that it can load is just many more, and catalytic active center is just many more, and its catalytic activity is just high more.Therefore, the carrier of catalyzer requires to have high specific surface area.In addition, the crystal phase structure of support of the catalyst also is an important factor that influences the reactivity worth of catalytic active component.SO for example ₄ ^2-/ ZrO ₂In the preparation process of solid super-strong acid, has the ZrO of tetragonal crystal structure ₂To more help forming solid super-strong acid (Catal.Rev.Sci.Eng., 38 (2), 329,1996).Zirconic crystal phase structure general normal be cubic and two kinds of monocline crystalline phases.Handle under the above highly compressed special conditions of high temperature and 20.0MPa more than 1000 ℃, zirconic crystal phase structure is the quadrature crystalline phase.

Chinese patent CNl267568A disclosed method is to adopt in autoclave hydro-thermal synthesizing high specific surface area ZrO ₂, the pressure when hydro-thermal is synthetic is 0.1～0.5MPa.The disclosed preparation of Chinese patent CNl260324A ZrO ₂Method, be after zirconium oxychloride aqueous solution and ammoniacal liquor are mixed, leave standstill agingly, form through different atmosphere drying, roasting.At Catal.Rev.Sci.Eng., summarized about zirconic preparation method in 38 (2), 329,1996.We find that the zirconium white that obtains through prior art for preparing usually is the mixing crystalline phase of four directions and monocline, and being difficult to obtain is cubic completely crystalline phase, the zirconium white that has high specific surface area again.

Summary of the invention

The purpose of this invention is to provide a kind of preparation and have complete cubic crystalline phase and the zirconic method of high-specific surface area.

Preparation method provided by the invention is that soluble zirconium salt brine solution and solubility strong alkali aqueous solution are mixed the Zr (OH) that hydrolysis obtains ₄Hydrogel carries out ageing handle after, after filtration, washing, drying and roasting obtain, it is characterized in that said ageing handle be stirring and normal pressure, 50～100 ℃ of temperature reflux and the condition of constant pH=7.5～14 under carried out 5～120 hours.

More particularly, preparation method provided by the invention contains following steps:

(1) zirconates with solubility is mixed with the aqueous solution that concentration is 0.2～10.0 mol, preferred 1.0～10.0 mol;

(2) solubility highly basic is mixed with the aqueous solution that concentration is 0.1～12.0 mol, preferred 2.0～8.0 mol;

(3) (1) and (2) is mixed hydrolysis and obtain Zr (OH) ₄Hydrogel;

(4) stirring and normal pressure, 50～100 ℃, preferred 55～95 ℃ of temperature reflux and constant pH=7.5～14,

Under preferred 8.0～12 the condition, to the Zr (OH) that obtains ₄Hydrogel carries out 5～120 hours, preferred 15～100 hours ageing to be handled;

(5) to the Zr (OH) after the ageing processing ₄Hydrogel filters repeatedly and washs repeatedly, detects less than Cl in filtrate ^-Till the ion.45～95 ℃ of dryings 15～36 hours, obtain zirconic forebody Zr (OH) then ₄

(6) under 400～900 ℃ temperature, roasting Zr (OH) in the air ₄Obtained zirconium white in 4～16 hours.

Among the preparation method provided by the invention, said solubility zirconates can be inorganic zirconates and/or organic zirconates.Wherein said inorganic zirconates is selected from ZrOCl ₂, ZrCl ₄, Zr (NO ₃) ₄Or ZrO (NO ₃) ₂Wherein said organic zirconates, general formula are (RO) ₄Zr, R are alkyl, for example, and oxyethyl group zirconium (C ₂H ₅O) ₄Zr and propoxy-zirconium (C ₃H ₇O) ₄Zr.

Among the preparation method provided by the invention, said solubility highly basic is selected from NaOH, KOH or NH ₄One of OH or its mixture.

Among the preparation method provided by the invention, the mixing of said zirconium saline solution and strong base solution can be that zirconium salt solution is added in the alkaline solution, also can be that strong base solution is added in the zirconium salt solution.

Preparation method provided by the invention is though only changed Zr (OH) ₄The ageing treatment condition of hydrogel, make its stirring and normal pressure, 50～100 ℃ of temperature reflux and the condition of constant pH=7.5～14 under carry out, but but can obtain the zirconium white of complete cubic crystalline phase, this is that unanticipated arrives, also be that the preparation method that provides of prior art is inaccessiable, from the X-ray diffraction spectrogram of embodiment and Comparative Examples gained sample, can obviously find out difference wherein; And the prepared zirconium white of the inventive method has big specific surface area, finds out that from example the specific surface of sample is all at 200 meters ²More than/the gram, be higher than 101 meters of comparative sample far away ²/ gram.

Description of drawings

Fig. 1 is the X-ray diffraction spectrogram of embodiment 1 sample Z-1 and Z-2.

The X-ray diffraction spectrogram of Fig. 2 comparative example Z-0.

Embodiment

The present invention is further illustrated below by embodiment, but they can not be interpreted as the qualification to protection domain of the present invention.

In an embodiment, zirconic crystal phase structure is determined with the X-ray diffraction method; The grain-size D of zirconia samples _HkjWith the Scherrer method calculate (H.P.Klug and L.E.Alexander, " X-rayDiffraction Procedure for Polycrystalline and Amorphous Materials ", 2nd Ed., Wiley, 1974).The Scherrer equation:

$D_{\mathrm{hkj}}=\frac{0.89\mathrm{\λ}}{B\cos {\mathrm{\θ}}_B}$

Wherein: λ: the beam wavelength of X-ray target ()

Halfwidth (the I of B:hkj diffraction peak _Max, be unit with the radian)

θ _B: 1/2 of 2 θ of hkj diffraction peak

In an embodiment, the specific surface area of zirconia samples is measured with the nitrogen adsorption method.

Embodiment 1

With 20g ZrOCl ₂8H ₂O (Beijing Chemical Plant, AR, down together) be dissolved in the 50ml distilled water, stirring is made into the ZrOCl that concentration is 1.2 mol after treating that solution is limpid fully ₂Solution.With 20ml ammoniacal liquor (25～28%, Beijing Yili Fine Chemicals Co., Ltd., AR, down with) mix with 150ml distilled water, be made into the NH of 2.1 mol ₄OH solution.

Under violent stirring and room temperature, with the ZrOCl for preparing ₂Solution is the NH of 2.1 mol with 1.0ml/ minute rate of addition adding concentration ₄In the OH solution.ZrOCl ₂After solution adds, continue to stir 30 minutes, at this moment the pH=9.4 of gel mother liquor.

The milky gel mother liquor that generates is changed in the three-necked bottle, under violent stirring and reflux conditions, be warmed up to 100 ℃, adding concentration with 10ml/ hour rate of addition simultaneously is the NH of 6.0 mol ₄OH solution keeps the pH=9.4 of mother liquor constant.The time of this ageing process is 48 hours.

Mother liquor after ageing finishes is through suction filtration and distilled water repetitive scrubbing filter cake, the Cl in filter cake ^-(AgNO till ion can't detect ₃Method detects, down together).The filter cake that obtains the vacuum tightness of 0.09MPa and 60 ℃ dry 30 hours down, obtains Zr (OH) in vacuum drying oven ₄

Zr (OH) with porphyrize ₄Put into muffle furnace, roasting 8 hours in 500 ℃ and 900 ℃ of air atmospheres respectively, the zirconium white ZrO that obtains ₂Sample is remembered respectively and is made Z-1 and Z-2.

The X-ray powder diffraction analytical results of Z-1 and Z-2 sample is seen Fig. 1, and as can be seen from Figure 1, their crystal phase structure all is cubic crystalline phase (Tetragonal, note by abridging be T), does not have monocline crystalline phase (Monoclinic, note by abridging be M) to occur.

The crystalline phase of Z-1 and Z-2 sample, grain size size and specific surface area see Table 1.

Comparative Examples

This Comparative Examples is according to document Catal.Rev.Sci.Eng., and the method for recording and narrating in 38 (2), 329,1996 prepares zirconium white.

With ZrOCl ₂Be made into the solution that concentration is 1.0M.With ammoniacal liquor (25～28%NH ₃) be made into the solution that concentration is 2.0M.Under agitation, the ammonia soln with 2.0M is added dropwise to ZrOCl lentamente ₂In the solution, obtain milky gel mother liquor.Under 50 ℃, ageing mother liquor 24 hours.Filter repeatedly then, wash, obtain not having Cl ^-The ionic filter cake.100 ℃ of dryings 12 hours 500 ℃ of roastings 8 hours, obtain zirconic comparative sample Z-0 at last.

The X-ray powder diffraction analytical results of Z-0 sample is seen Fig. 2, and as can be seen from Figure 2, crystal phase structure is the mixing crystalline phase of four directions (T) and monocline (M).

The crystal phase structure of Z-0 sample, grain size size and specific surface area see Table 1.

Embodiment 2

With 40g ZrO (NO ₃) ₂6H ₂O (Beijing Chemical Plant, AR, down together) be dissolved in the 50ml distilled water, after stirring treated that solution is limpid fully, being made into concentration was the ZrO (NO of 2.6 mol ₃) ₂Solution.20ml ammoniacal liquor (25～28%) is mixed with 100ml distilled water, be made into the NH of 3.2 mol ₄OH solution.

Under violent stirring and room temperature, with the ZrO (NO for preparing ₃) ₂Solution is the NH of 3.2 mol with 0.25ml/ minute rate of addition adding concentration ₄In the OH solution.ZrO (NO ₃) ₂After solution adds, continue to stir 30 minutes, at this moment the pH=8.5 of gel mother liquor.

The milky gel mother liquor that generates is changed in the three-necked bottle, under violent stirring and reflux conditions, be warmed up to 70 ℃, adding concentration with 8ml/ hour rate of addition simultaneously is the NH of 4.0 mol ₄OH solution keeps the pH=8.5 of mother liquor constant.The time of this ageing process is 80 hours.

Suction filtration, washing, drying and roasting process (600 ℃ of roastings) are identical with embodiment 1.The ZrO that obtains ₂The sample note is made Z-3.

The crystal phase structure of Z-3 sample, grain size size and specific surface area see Table 1.

Embodiment 3

With 20g ZrOCl ₂8H ₂O is dissolved in the 50ml distilled water, is made into the ZrOCl that concentration is 1.2 mol ₂Solution.(Beijing Yili Fine Chemicals Co., Ltd. AR) is mixed with 250ml distilled water, is made into the KOH solution of 2.5 mol with 35g KOH.

Under violent stirring and room temperature, with the ZrOCl for preparing ₂Solution is in the KOH solution of 2.5 mol with 1.0ml/ minute rate of addition adding concentration.ZrOCl ₂After solution adds, continue to stir 30 minutes, at this moment the pH=13.7 of gel mother liquor.

The milky gel mother liquor that generates is changed in the three-necked bottle, under violent stirring and reflux conditions, be warmed up to 100 ℃, ageing 24 hours.

Suction filtration, washing, drying and roasting process (600 ℃ of roastings) are identical with embodiment 1.The ZrO that obtains ₂The sample note is made Z-4.

The crystal phase structure of Z-4 sample, grain size size and specific surface area see Table 1.

Embodiment 4

With 20g ZrOCl ₂GH ₂O is dissolved in the 50ml distilled water, is made into the ZrOCl that concentration is 1.2 mol ₂Solution.(Beijing Yili Fine Chemicals Co., Ltd. AR) is mixed with 300ml distilled water, is made into the NaOH solution of 3.0 mol with 36g NaOH.

Under violent stirring and room temperature, with the ZrOCl for preparing ₂Solution is in the NaOH solution of 3.0 mol with 2.0ml/ minute rate of addition adding concentration.ZrOCl ₂After solution adds, continue to stir 30 minutes, at this moment the pH=13.8 of gel mother liquor.

The milky gel mother liquor that generates is changed in the three-necked bottle, under violent stirring and reflux conditions, be warmed up to 80 ℃, ageing 48 hours.

Suction filtration, washing, drying and roasting process (600 ℃ of roastings) are identical with embodiment 1.The ZrO that obtains ₂The sample note is made Z-5.

The crystal phase structure of Z-5 sample, grain size size and specific surface area see Table 1.

Embodiment 5

With 80g ZrCl ₄4H ₂O (Beijing Chemical Plant, AR, down together) be dissolved in the 100ml distilled water, stirring is made into the ZrCl that concentration is 2.6 mol after treating that solution is limpid fully ₄Solution.20ml ammoniacal liquor is mixed with 150ml distilled water, be made into the NH of 2.1 mol ₄OH solution.

Under violent stirring and room temperature, with the ZrCl for preparing ₄Solution is the NH of 4.0 mol with 2.0ml/ minute rate of addition adding concentration ₄In the OH solution.ZrCl ₄After solution adds, continue to stir 30 minutes, at this moment the pH=9.2 of gel mother liquor.

The milky gel mother liquor that generates being changed in the three-necked bottle, under violent stirring and reflux conditions, heats up 100 ℃, is the NH of 2.1 mol with 5ml/ hour rate of addition adding concentration simultaneously ₄OH solution keeps the pH=9.2 of mother liquor constant.The time of this ageing process is 50 hours.

Suction filtration, washing, drying and roasting process (600 ℃ of roastings) are identical with embodiment 1.The ZrO that obtains ₂The sample note is made Z-6.

The crystal phase structure of Z-6 sample, grain size size and specific surface area see Table 1.

Embodiment 6

With 20g ZrOCl ₂8H ₂O is dissolved in the 50ml distilled water, and stirring is made into the ZrOCl that concentration is 1.2 mol after treating that solution is limpid fully ₂Solution.1.0 the NH of mol ₄The KOH solution of OH solution and 1.0 mol mixes as basic solution.

Under violent stirring and room temperature, with the ZrOCl for preparing ₂Solution adds in the basic solution.ZrOCl ₂After solution adds, continue to stir 30 minutes, at this moment the pH=12 of gel mother liquor.The milky gel mother liquor that generates is changed in the three-necked bottle, and under violent stirring and reflux conditions, at 55 ℃, adding concentration is the NH of 6.0 mol ₄OH solution keeps the pH=12 of mother liquor constant.The time of this ageing process is 100 hours.Suction filtration, washing, drying and roasting process (600 ℃ of roastings) are identical with embodiment 1.The ZrO that obtains ₂The sample note is made Z-7.

The crystal phase structure of Z-7 sample, grain size size and specific surface area see Table 1.

Embodiment 7

With 15g propoxy-zirconium (C ₃H ₇O) ₄-Zr is dissolved in the 150ml distilled water, and after stirring treated that solution is limpid fully, being made into concentration was the propoxy-zirconium solution of 0.3 mol.1.0 the NH of mol ₄OH solution is as basic solution.

Under violent stirring and room temperature, with the ZrOCl for preparing ₂Solution adds in the basic solution.ZrOCl ₂After solution adds, continue to stir 30 minutes, at this moment the pH=8.0 of gel mother liquor.The milky gel mother liquor that generates is changed in the three-necked bottle, under violent stirring and reflux conditions, be warmed up to 95 ℃, adding concentration is the NH of 6.0 mol ₄OH solution keeps the pH=8.0 of mother liquor constant.The time of this ageing process is 15 hours.Suction filtration, washing, drying and roasting process (600 ℃ of roastings) are identical with embodiment 1.The ZrO that obtains ₂The sample note is made Z-8.

The crystal phase structure of Z-8 sample, grain size size and specific surface area see Table 1.

Table 1

??ZrO 2Sample	Crystalline phase	Grain-size, nm	Specific surface, m 2/g
				????Z-1 ????Z-2 ????Z-3 ????Z-4 ????Z-5 ????Z-6 ????Z-7 ????Z-8 ????Z-0	????T ????T ????T ????T ????T ????T ????T ????T ????M+T	????2.0 ????2.5 ????1.8 ????1.9 ????2.0 ????2.0 ????2.8 ????3.0 ????25.0	????289 ????256 ????310 ????298 ????287 ????281 ????234 ????229 ????101

Claims (12)

1, a kind of zirconic preparation method, this method mix the Zr (OH) that hydrolysis obtains with soluble zirconium salt brine solution and solubility strong alkali aqueous solution ₄Hydrogel carries out ageing handle after, after filtration, washing, drying and roasting obtain, it is characterized in that said ageing handle be stirring and normal pressure, 50～100 ℃ of temperature reflux and the condition of constant pH=7.5～14 under carried out 5～120 hours.

2, according to the said method of claim 1, wherein said solubility zirconates is selected from inorganic zirconates and/or organic zirconates.

3, according to the said method of claim 2, wherein said inorganic zirconates is selected from ZrOCl ₂, ZrCl ₄, Zr (NO ₃) ₄, ZrO (NO ₃) ₂

4, according to the said method of claim 2, wherein said organic zirconates general formula is (RO) ₄Zr, wherein R is an alkyl.

5, according to the said method of claim 4, wherein said organic zirconates is oxyethyl group zirconium (C ₂H ₅O) ₄Zr or propoxy-zirconium (C ₃H ₇O) ₄Zr.

6, according to the said method of claim 1, wherein said solubility highly basic is selected from NaOH, KOH or NH ₄One of OH or its mixture.

7, according to the said method of claim 1, the mixing of wherein said zirconium saline solution and strong alkali aqueous solution is that zirconium saline solution is added in the alkaline solution, or alkaline solution is added in the zirconium saline solution.

8, according to the said method of claim 1, wherein said zirconium saline solution concentration is 0.2～10.0 mol.

9, according to the said method of claim 8, wherein said zirconium saline solution concentration is 1.0～10.0 mol.

10, according to the said method of claim 1, wherein said solubility strong base solution concentration is 0.1～12.0 mol.

11, according to the said method of claim 10, wherein said solubility strong base solution concentration is 2.0～8.0 mol.

12, according to the said method of claim 1, wherein said aging be reflux in stirring and normal pressure, 55～95 ℃ of temperature and the condition of constant pH=8.0～12 under, to the Zr (OH) that obtains ₄Hydrogel carries out 15～100 hours processing.

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