Method of producing mixture of aluminium and zirconium oxides

专利摘要:
Mixed oxides of alumina and zirconia having a controlled granulometric distribution, consisting essentially of spherical, submicronic particles, wherein zirconia is distributed uniformly in alumina and may reach 38% by weight, said zirconia being in the stabilized form at room temperture in the tetragonal phase after having subjected the amorphous hydrated composite oxides to thermal treatments, wherein the transition occurs of zirconia to the tetragonal phase.
公开号:SU1609442A3
申请号:SU864027646
申请日:1986-06-02
公开日:1990-11-23
发明作者:Монтино Франко；Спото Джузеппе
申请人:Монтэдисон С.П.А. (Фирма)；
IPC主号:

专利说明:

The invention relates to methods for producing a mixture of oxides of aluminum and zirconium, containing mainly spherical particles having a size less than a micron.
The purpose of the invention is to improve the quality of the product by producing spherical granules of 0.1-1 microns in size and
the dispersion index dw / dn is not higher than 2, where dw is the weight average diameter, dn is the numerical average diameter.
In order to obtain a mixture of amorphous aluminum and zirconium oxides in accordance with the invention, an aluminum salt is taken as a solution with a concentration of i3 +
mi Al up to 0.3 mol / l, preferably 0.2 mol / l. The specified aluminum salt is at least 80% by weight of aluminum sulphate. The zirconium salt, soluble in the reaction conditions, is taken in an amount to reach a maximum of 38% by weight in the form of Zr02 based on the weight of Al203 and Zr02 on the product calcined at 1000 ° C for 2 hours, and by effecting the precipitation of a mixture of hydrated aluminas and zirconium in the presence of cationic polyelectrolytes, soluble under the reaction conditions and having an average molecular weight of more than 1 million and a degree of ionization of at least 3 meq / g. This is carried out under such conditions as to obtain a homogeneous precipitation in the presence of substances, able to emit OH ions, and; In addition, work in the presence of NAZig, in such quantities as to dissolve the precipitate, which appears during preparing the stock solution at room temperature.
Another solution consists in the hpn preparation of the initial solution by adding aluminum to the polymer under the reaction conditions of polyelectrolyte and converting to base a substance capable of releasing OH ions in the solution oxidation to a value of at least pH 3 followed by the addition of zirconium salt and sulfate.
The sulfate salt is added in an equimolar amount relative to the sulfuric acid used in this method, however in this case you can use: smaller amounts of sulfate (depending on the amount of zirconium used).
It is recommended that cationic polyelectrolytes have a degree of ionization of more than 3.5 meq / g and a molecular weight in the range of 3-6 million.
The polyelectrolytes in accordance with the invention are used in amounts from more than 2.5% by weight to a theoretical amount of Al2O3 corresponding to the initial aluminum present in the solution. It is recommended to use quantities of polyelectrolyte greater than 3% by weight, in particular 3.3% by weight. Polyelectrolytes are recommended to be dissolved in water at concentrations usually 1 or 2 g / l before use. Amounts of polyelectrolyte greater than these can be used, for example, about 7 or 20 wt.%, In this case no significant changes in the morphology and particle size distribution of the particles to about 7.5 wt.% Occur. If the amount of polyelectrolyte exceeds 7.8 wt.%, A reduction in particle diameter is achieved, for example, for concentrations of 20 wt.% Polyelectrolyte, the diameter varies from 0.3 to 0.2 µm.
Best results are obtained with a concentration of ionic groups corresponding to at least 3 meq / g. It is recommended that the number of cationic groups be more than 4 meq / g.
PRI me R 1. 0.6 g of an Ecoclar 8017 polyelectrolyte containing repeating units of the formula
- SNO-CH I
n
HN-CHn-NHCl
 I
SNS
with a molecular weight of 3-4 ppm and a positive degree of ionization of 4.94 meq / g, is dissolved with 330 ml of water with stirring.
Then, 190 ml of a solution containing 200 g / l of A12 (504) h-18 H20 (0.6 mol / l Al, 13 Ml of concentrated H2 SO4 (96%), 96 g of urea and 10 ml of a solution containing 171 , 73 g / l2 oGOS12 6N20 (0.6 mol / lU, the urea content was 160 g / l, Zr
0.001 mol / l. The final volume of the solution is about 600 ml.
The solution is then poured into a flask equipped with an irrigation cooler, a thermometer and an electrode to measure pH, and
heated without stirring to 100 ° C. The pH increases from 1.3 to 5.5 in about 135 minutes, at about pH 3.4 an opalescence appears, the intensity of which increases rapidly with increasing pH.
The precipitate obtained after filtration is washed and dried at 120 ° C for several hours. 12.5 g of a mixture of hydrated alumina and zirconia are obtained, the analysis by means of an electron microscope transmission shows that such a compound contains essentially spherical, identical and approximately monodisperse particles (dw / dn 1.19) whose diameter is approximately equal to 0, 3 microns.
X-ray powder spectrum shows that the sample is amorphous.
Under the conditions of this example, the total number of S04n / Zrn is 67.5, Zr02 is 11.30 wt.% (Nominally) of the final product.
Example 2. 180 ml of a solution containing 200 g / l A12 (504) C 18 H20.18 ml 96%
H2S04.96 g of urea and 20 ml of a solution containing 171.73 g / l of ZrOCl2-H20 are added to 0.6 g of the product Ecoclar 8017 and dissolved with stirring in 330 ml of water. The urea solution content is 158 g / l, 0.02 mol / l. The solution is heated to 100 ° C using the device described in Example 1.
Initially, the pH value is 1.6 and reaches a value of 3.3 after 80 minutes. At this point a slight opalescence is observed, the intensity of which increases rapidly with decreasing acidity of the solution. When, after about 135 minutes, the pH reaches 5.5, the precipitate formed is filtered, washed and dried in an oven at 120 ° C.
The product was obtained in an amount of 13.60 g, which, as shown by fluoroscopic analysis, turned out to be amorphous, but, as shown by the analysis in the transmission microscope, it has a narrow particle size dispersion and an average diameter of about 0.25 µm.
Under these conditions, S04 / Zr is 40.5, while Zr02 is nominally 21.20 May. %
Froze The test described in example 2 is repeated, but using 0.3 g (0.5 g / l) of the product Ecoclar 8017. The transmission microscopic analysis shows that the product still contains spheroidal particles with a diameter slightly larger than the diameter of the particles. Example 2 (about 0.4 microns), which were somewhat more agglomerated.
EXAMPLE 4 The test described in Example 3 was repeated using 1.2 g (2 g / l) of Ecoclar 8017. It was found that the product contains identical spherical particles, which are slightly agglomerated and have a narrow particle size dispersion. and an average diameter of 0.2 microns.
EXAMPLE 5 The test described in Example 2 was repeated using 48 g of urea instead of 96 g. In this case, it turned out that increasing the pH when heated to 100 ° C is much slower, resulting in a pH value exceeding 1 6 after only 200 minutes After continuing the reaction for 6 hours until pH 5.5, a mixture of hydrated oxides was obtained with the same characteristics as the mixture of Example 2.
EXAMPLE 6 The test described in example 2 was repeated using 20 ml of a solution containing 0.6 mol / l Zr (S04) 2 -HaO instead of ZrOCi2-6 N26. The total ratio is 504 MZr 43.3.

The obtained precipitate after drying with (14 g) does not differ from either morphological or particle size points of view from the precipitate obtained in Example 5 2.
Example 7: 180 ml of a solution containing 200 g / l Al2 (S04) 3 18 H20.96 g of urea and 42.82 g of (NH4) 2 SO4 are added to 0.6 g of the product Ecoclar 8017 and the solution They are mixed with 10 vanities of PCOs. A pH value of 3.5 is adjusted to 2.8 with 0.5 ml of H2 SO4, then 20 ml of a solution containing 171.73 g / l of ZrOCl2-6 H2O is added, and the volume is adjusted to 600 ml with water. . Under these conditions, 15 SO / 2- / Zr n 40.1.
When heated to 1pO ° C in the device described in Example 1, the pH is increased from 2.63 to 5.5 over 55 minutes. The resulting precipitate, as shown by analysis in an electron microscope transmission, has no differences with either morphological or particle size distribution. points of view from the sediment obtained in the test described in Example 3.
PRI me R 8. The test is conducted in according to the operating conditions of Example 4, but a rotary paddle stirrer having a speed of 260 rpm is added to this device. An electron microscope analysis of the transmittance shows that the sediment is neither morphologically nor 30 different in the particle size distribution of the particles making up the sediment.
PRI me R 9. Dissolve with stirring 0.6 g of the product Ecoclar 8017 in 20 ml of water and add 170 ml of a solution containing 35 g 200 l / l of A12 (504) H-18 H2O, 176 ml of a solution containing 96 g of urea, 23.5 ml of 96% H2SO4 and 30 ml of a solution containing 171.73 g / l of ZrOCt2-6 N20.
When heated to pH, it changes from 40 1.8 to 5.5 in 170 minutes, and a precipitate is formed, which, after filtration, washing and drying at 120 ° C, as shown by an electron transmission microscope, contains particles, having characteristics similar to those specified in the previous examples.
Under these conditions, Zr02- (nominally) is 29.9% by weight, in addition, the overall ratio. it turned out 0 is equal to 31.6.
The powder X-ray spectrum shows that the product is amorphous.
Example 10. 1.2 g of product is dissolved.
Ecoclar 8017 in 350 ml of water, and then 96 g of urea, 27 cm of 96% H2SO4 are added,
160 ml of solution containing 200 g / l
A12 (504) C 18 H20, and 40 ml of a solution containing 171.73 g / l ZrOCb 6Н20.
At the end of the test carried out in accordance with the indicated method, 14.58 g of an amorphous precipitate containing spheroid particles with an average diameter of 0.2 µm was obtained.
Under test conditions, the concentration of ZrOa (nominal) is 37.7 wt.%, The total ratio SO / iH / LZr is 26.25.
EXAMPLE 11 Example 9 is repeated, but a total molar ratio of 40 is used. To obtain this, the lead was maintained; grades are used (NH4bS04.
The resulting product has the same morphological and granulometric characteristics as the product of example 10.
. EXAMPLE 12 18 ml of 96% HzSO-i, 96 g of urea, 140 ml of a 0.3 M solution; A12 (504) g-18H20 and 60 ml of a 0.6 M solution; ZrOCl2 6H20 added 0.6 g of iEcociar 8017 dissolved in 330 ml of water are used.
In these conditions, the nominal concentration of Zr02 is 50.89% by weight and the total SQ4 / Zr ratio is 12.5.
The test is completed (pH 5.5) after heating to 100 ° C for 115 minutes. After drying the obtained precipitate (14.9 g), the product contains particles having a very irregular morphology, the particles are not spherical and slightly agglomerated.
PRI me R 13. The product obtained in Example 2 was subjected to heat treatment at 900 ° C for 60 minutes.
; The resulting product has particles with preserved sphericity I, and the presence of agglomerates is not marked; The morphology I is maintained, the particle diameter is 10% smaller than in Example 1. The x-ray powder spectrum showed the presence of gamma and delta A1203 and Zr02 in the tetragonal crystalline phase.
Example 14 Example 13 is repeated by heat treatment at 700 ° C for 3 hours. A heating curve C is used. A steepness of 250 ° C / h. The particles remain spherical when the diameter is reduced by 5% compared with the product of example 3. The presence of the aggregate is not marked and H is-. the numerical distribution is unchanged compared with example 13.
The X-ray powder spectrum of the sample thus treated showed that Zr02 was in the tetragonal phase, and AlaOs was in the gamma phase.
Example 5. Example 14 is repeated by heat treatment all the time at the same temperature and for the same time, but the sample is introduced directly into the furnace from room temperature to the processing temperature.
The results are similar to the results of example 14.
Example 16. The product obtained
after treatment, as in example 13, is subjected to heat treatment at 1140 ° C for 15 minutes An instantaneous heating curve is used, similar to that used in
Example 15. The product retains the same morphological characteristics as the product of Example 13. This product, as shown by X-ray analysis, contains a mixture of delta and theta A1203 and Zr02 in the tetragonal crystalline phase.
The yield of the obtained crystal mixture of oxides is approximately equal to the theoretical (98%) compared with the amorphous product obtained in Example 2.
Based on X-ray spectra, the average crystal size of Zr02 turned out to be
about equal to 245 A.
PRI me R 17. The product obtained in
Example 1 is subjected to the same heat treatment as in Example 16. The morphology and particle size distribution of the particles are the same as in Example 1. The diameter of the particles is reduced by about 8%.
X-ray powder analysis indicates the presence of the same crystalline phases. as in Example 13, for Al203, ZrOa is present in the tetragonal phase. PRI me R 18. The product obtained in
example 17, subjected to heat treatment
at 1250 ° C for 30 min, x-ray
the analysis indicates the presence of A120z in
alpha phase and Zr02 in the tetragonal phase.
The average size of Zr02 crystals. determined by x-ray spectra
Salaus equal to 365 A.
The yield of the obtained crystal mixture of oxides is close to theoretical, compared with the amorphous product obtained in Example 1.
Example 19. Example 1 is repeated using 0.6 g of the product Ecoclar 8337, with the cationic polyislectrolyte having an average molecular weight of 4-5 million, and the degree of ionization is 4.99 meq / g. This polyelectrolyte consists of repeating units of the formula
-CH2-CH
HN.-CH-NHC1 CH
The precipitated mixture of oxides has characteristics similar to those shown in example 1.
Example 20: Example 19 is repeated using 0.6 g of Praestol 444K product containing repeating units of the formula
-CH2- CH
CH.
solution with a concentration of up to 0.3 mol / l, and at least 80 wt.% it consists of aluminum sulfate, and zirconium salt is taken in an amount that provides
its product is not more than 38 wt.% after calcination at 1000 ° C for 2 h, the precipitation is carried out in the presence of soluble cationic polyelectrolytes containing repeating units based on the substitution of acrylamide having the general formula
HN-CH-NHS04 Н СНз
The cationic polyselectrolyte has an average molecular weight of 4 million, and the degree of ionization is 4.24 meq / g.
In solution, the content of polyelectrolyte, urea, and Zr is as in Example 19. The precipitated mixture of oxides has characteristics similar to those of Example 1.
EXAMPLE 21 Example 19 is repeated using 0.6 g of Praestol 334K product, the cationic polyelectrolyte having an average molecular weight of 3 ppm, and the degree of ionization is 3.97 meq / g. Praestol 334K consists of repeating units of the formula
-CH2-SSNz
HN-CH-NHS04 N CgNz
in solution, the content of poly-electrolyte, urea, and Zr is the same as in Example 22. The resulting mixture has characteristics similar to those of Example 1.
The proposed method allows to obtain a granular spherical product with a size of 0.1-1 microns.
3). A method for producing a mixture of aluminum and zirconium oxides, including mixing aluminum and zirconium salts and treating said salts with a precipitant, separating the precipitation product and calcining it, that, in order to improve the quality of the product due to the production of spherical granules with a size of 0.1-1 µm and a dispersion index dw / dn not higher than 2, where dw is the weight average diameter, dn is the numerical average diameter, salt, aluminum is taken as 15
-CH,
 R,

权利要求:
Claims (1)
[1]
I U NT-CH-NR X
Z ro
where RI, R2, R3 and T are equal to or different from each other and are selected from the group containing hydrogen and a hydrocarbon radical containing from 1 to 4 carbon atoms;
Z and Y.-H, -CH3; X anion; P is an integer
soluble in the reaction conditions and having an average mol. mae. more than 1 million and a degree of ionization of not less than 3 meq / g, while the precipitation is carried out in the presence of sulfuric acid.
52. The method according to claim 1, about tl and h
in that the concentration of the aluminum salt is 0.2 ml / l.
3. The method according to claim 1, characterized in that the initial solution of the aluminum salt,
0 polyelectrolyte, precipitated spruce acidified to a pH of less than 3, then a zirconium salt and aluminum sulfate are added in a quantity equivalent to sulfuric acid.
4. The method according to claim 1, wherein 5 the cationic polyelectrolyte has
the degree of ionization of more than 3.5 meq / g and the average mol.mae., equal to 3 million.
5. The method according to claim 1, wherein the cationic poly-electrolyte is used in amounts greater than or equal to 3.3 wt.% With respect to the theoretical alumina present in the solution.
6. The method according to claim 5. characterized in that cationic polyselectrolyte is used in amounts greater than or equal to 10% by weight.
7. A method according to claim 1, characterized in that a polyelectrolyte is used which also contains, in addition to ionic units.
11 160944212
neutral units of unsubstituted ak-8. The pop method 1 is different.
of rilamide having the general formula that a cationic polyelectrolyte consists
g g h / 1 of a copolymer containing the above indicated | Cn2 CY2Ji positive positively charged units and
R . neutral units other than ones
Iacrylamide and statistically distributed NHH along the polymer chain.
9. The method according to p. 1, about tl and h a y i and with
where m and Y2 have the indicated meanings for Y, using as the precipitant
and p, 10 urea or formamide.
and ionic and neutral units of distribution-10. The method of claim 9, wherein
Lena, statistically, along the polymer, because the temperature of the treatment with the precipitator
pi.support 90-100 ° C

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法律状态:

优先权:

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申请号 | 申请日 | 专利标题

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IT21018/85A|IT1186728B|1985-06-04|1985-06-04|MIXED ALUMINUM AND ZIRCONIA OXIDES IN THE FORM OF SPHERICAL PARTICLES WITH RESTRICTED GRANULOMETRIC DISTRIBUTION AND PROCESS FOR THEIR PREPARATION|

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