JPH0532417A - Production of antimony pentoxide hydrate - Google Patents

Abstract

PURPOSE:To provide a method for producing mass-producible crystalline antimony pentoxide hydrate suitable for an industrial method for production in which the high-purity antimony pentoxide hydrate, having a high cation exchange capacity and a low concentration of residual anionic impurities and useful as inorganic ion exchangers and resin fillers can be produced. CONSTITUTION:This method is to produce crystalline antimony pentoxide hydrate having a chlorinating step for chlorinating antimony trichloride and providing antimony pentachloride, a partially hydrolyzing step for adding water at 0.15-1 weight ratio (H2O/SbCl5) of water/antimony pentachloride to the resultant antimony pentachloride and carrying out partial hydrolysis, a completely hydrolyzing step for completely hydrolyzing the obtained partial hydrolyzate with water in a volume of 10-50 times based on the volume of the produced antimony pentachloride, a crystallizing step for heating the resultant hydrolyzate under conditions of 80-150 deg.C and 1-10hr under ordinary or a highly pressure and crystallizing the hydrolyzate and a washing step for washing the prepared substance subjected to crystallizing treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing antimony pentoxide hydrate from antimony trichloride as a raw material, which has a high purity, a high cation exchange capacity and a low residual anion impurity concentration. It relates to a method for producing highly pure crystalline antimony pentoxide hydrate.

[0002]

2. Description of the Related Art Antimony pentoxide hydrate is a synthetic resin,
Not only is it used as a flame retardant for fibers and the like as a resin filler to be mixed into a resin, but also as an inorganic ion exchanger for inorganic ions such as sodium ions.

As a method for producing such an antimony pentaoxide hydrate, for example, antimony pentachloride (Sb) is used.
Cl ₅ ) is hydrolyzed (Japanese Patent Application Laid-Open No. 49-45,89).
No. 1), a method of oxidizing antimony trioxide (Sb ₂ O ₃ ) (JP-A-52-123,997), and a method of oxidizing antimony trichloride (SbCl ₃ ) (JP-A-63-63). No. 185,822) and the like are known. However, in the method of hydrolyzing the above antimony pentachloride, it is possible to obtain an amorphous state or a glassy state but not a crystalline state, and it is not possible to obtain a high cation exchange capacity. In addition, in the method of oxidizing antimony trioxide, a high-purity antimony pentaoxide hydrate cannot be obtained, and moreover, the step of producing antimony trioxide and oxidizing it is complicated, and as a whole, There is a problem that the product cost becomes high, and further,
In the above-mentioned method of oxidizing antimony trichloride, there is a problem that the reaction proceeds rapidly and it is dangerous to react in a large amount, which is not suitable as an industrial production method.

By the way, when such an antimony pentoxide hydrate is used as a resin filler, the particle shape and size are uniform and the dispersibility in the resin is excellent, and For example, when it is used as a flame retardant for IC encapsulating resin, it is required to have high purity without any anionic impurities for the purpose of solving the problem of corrosion of aluminum wiring and improving the service life. It When this antimony pentoxide hydrate is used as an inorganic ion exchanger, not only is it uniform in particle shape and size and has a high specific surface area, but it is usually used as a cation exchanger. Therefore, for example, a high cation exchange capacity for sodium ions is required, for which it is better to be in a crystalline state than in an amorphous state, and the higher the crystallinity, the better, Furthermore, it is necessary that the amount of cationic impurities contained in itself is small. This antimony pentoxide hydrate is not only used as a cation exchanger, but is also used as a mixture with an anion exchanger such as a bismuth compound in the case of IC resin encapsulation. However, when used in combination, a decrease in ion exchange capacity may be observed when each is used alone. As a result of investigating the cause, it was found to be caused by Cl ⁻ ions contained in the conventional antimony pentoxide. Therefore, it has been found that it is necessary to reduce the content of such anion impurities as much as possible so as not to impair the anion exchange capacity of the anion exchanger used in combination. Therefore, in the antimony pentoxide hydrate used for the inorganic ion exchanger, not only the cation exchange capacity is increased, but the contents of both anion and cation impurities are reduced as much as possible. There is a need.

[0005]

Therefore, the inventor of the present invention
It is possible to solve various problems in the conventional method,
As a resin filler and / or as an inorganic ion exchanger, earnest research is repeated to develop a new method for producing a hydrated antimony pentoxide capable of producing a hydrated antimony pentoxide having the required performance. The present invention has been completed. Therefore, the object of the present invention is to have a high cation exchange capacity and a low residual anion impurity concentration, and
It is an object of the present invention to provide a method for producing highly pure crystalline antimony pentoxide hydrate, which can be mass-produced and is suitable for an industrial production method. Further, the object of the present invention is to provide 1-5 molecules of water as crystallization water, a narrow particle shape and particle distribution, a uniform size, a high specific surface area, and a high-purity crystalline material suitable for an inorganic ion exchanger. It is to provide a method for producing an antimony pentoxide hydrate. Further, an object of the present invention is a high-purity crystal which has a uniform particle shape and size and is excellent in dispersibility in a resin, and which is useful as a resin filler used as a flame retardant for IC sealing resin, for example. It is to provide a method for producing a high quality antimony pentoxide hydrate.

[0006]

[Means for Solving the Problems] That is, the present invention relates to a chlorination step of chlorinating antimony trichloride into antimony pentachloride, and to the resulting antimony pentachloride in a water / antimony pentachloride weight ratio (H ₂ O). / SbCl ₅ ) 0.15 to 1 of water is added to carry out a partial hydrolysis step, and the resulting partial hydrolysis product is produced. A complete hydrolysis step of completely hydrolyzing with water, and a crystallization step of heating and crystallization of the obtained hydrolysis product under conditions of 80 to 150 ° C. and 1 to 10 hours under normal pressure or pressure, A method for producing an antimony pentoxide hydrate, which comprises a washing step of washing the obtained crystallized product.

In the method of the present invention, the antimony trichloride used as a raw material may be produced by any method, but the purity is preferably 99.0% by weight.
The above is more preferable, the purity of which is 99.99% by weight or more purified by distillation, the content of impurities of heavy metals is 1.0 ppm or less, and radioactive elements such as uranium and thorium. Impurity content of 0.5p
It is preferably pb or less.

In the chlorination step of chlorinating this antimony trichloride into antimony pentachloride, antimony trichloride 8
An aqueous solution containing 0 to 90% by weight, or an aqueous hydrochloric acid solution containing 30 to 80% by weight of antimony trichloride and 15 to 35% by weight of hydrochloric acid (provided that the molar ratio of hydrochloric acid to antimony pentachloride formed at the end of the reaction is 5 or less. In an aqueous solution of antimony trichloride or an aqueous hydrochloric acid solution at room temperature to 80 ° C., preferably 35 to 65 ° C., 1.01 to 1.1 times the stoichiometric equivalent, preferably 1.02
Chlorine gas of 5 to 1.075 times is introduced and reacted. Generation of hydrogen chloride gas can be suppressed by chlorinating antimony trichloride as an aqueous solution or an aqueous hydrochloric acid solution, and by maintaining the antimony trichloride concentration or the hydrochloric acid concentration in these aqueous solutions or hydrochloric acid solutions within the above range, The solidification of antimony trichloride is prevented, and its hydrolysis is also prevented. The end point of the reaction can be easily determined by measuring the change in redox potential.

The chlorination reaction mixture obtained in this chlorination step is optionally purified by distillation for the purpose of removing radioactive isotopes such as chlorine, antimony trichloride or uranium contained in this reaction mixture. The distillation carried out for this purpose is preferably carried out under reduced pressure at a temperature of 70 to 100 ° C. This antimony pentachloride is, for example, 93
Obtained as a fraction of ° C / 43.7 mmHg. As a result, chlorine or other impurities occluded in the antimony pentachloride generated in the subsequent stage can be reduced.

The antimony pentachloride obtained in the chlorination step is then subjected to a partial hydrolysis step in which water, for example deionized pure water, is added for partial hydrolysis. In this case, it is not preferable to add antimony pentachloride to water for hydrolysis. The antimony pentachloride to be subjected to this partial hydrolysis may be the reaction product obtained in the chlorination step of antimony trichloride, or the antimony pentachloride purified by further distilling the reaction product. May be Further, the amount of water used for this partial hydrolysis is the water / antimony pentachloride weight ratio (H ₂ O /
SbCl ₅₎ 0.15~1, preferably 0.4 to 0.8
Is. If this water / antimony pentachloride weight ratio is less than 0.15, hydrolysis does not proceed properly, and if it exceeds 1, hydrolysis will proceed rapidly, and those with uniform crystal grain size or high purity will be produced. The problem that it is difficult to obtain arises.
This partial hydrolysis reaction is carried out at a temperature of 0 to 60 ° C., preferably 30 to 50 ° C. for 1 to 2 hours, and the partial hydrolysis product is obtained as a yellow transparent liquid.

The partially hydrolyzed product thus obtained is then completely hydrolyzed in the presence of an excess of water. In this case, the antimony pentachloride aqueous solution is added to pure water. Alternatively, a method of adding an antimony pentachloride aqueous solution to pure water may be used. The amount of water used in this complete hydrolysis step is water / antimony pentachloride weight ratio (H ₂ O / SbCl ₅ ) 4.35 to 21.7, preferably 8.7 to 17.4. When the water / antimony pentachloride weight ratio is less than 4.35, the formed antimony pentoxide hydrate [Sb ₂ O ₅
nH ₂ O (n: 1 to 5)] and the yield decreases,
On the other hand, if it is larger than 21.7, the amount of treated water increases and the auxiliary equipment becomes large, which is not preferable in terms of cost. This complete hydrolysis reaction is carried out at a temperature of 0 to 70 ° C, preferably 30 to 60 ° C.
The reaction product is obtained as a slurry in which an amorphous substance and a crystallized substance are mixed. The reaction product of the complete hydrolysis reaction thus obtained is as it is,
Alternatively, once filtered and washed with water to recover antimony pentoxide hydrate, the antimony pentoxide hydrate is put into pure water again to prepare a 5 to 30 wt% slurry liquid, which is then subjected to the next crystallization step. In this case, the antimony pentoxide hydrate is recovered by filtration and washing with water, and then the antimony pentoxide hydrate is added again to 5 to 30 times.
By subjecting it to the next crystallization step as a wt% slurry, there is an advantage that dissociated hydrochloric acid can be removed and impurities such as adsorbed hydrochloric acid can be reduced.

The hydrolysis product obtained in the complete hydrolysis step is then subjected to crystallization treatment under normal pressure or under pressure. If it is carried out under pressure, crystallization and high purification can be achieved at the same time. Therefore, it is preferable. In this case, under normal pressure at 80-100 ° C,
Under pressure, the pressure is 1.5 to 6 atmospheres, preferably 2 to 5 atmospheres, 80 to 150 ° C., preferably 100 to 130 ° C., and each treatment time is 1 to 10 hours, preferably 2 to 8 hours. Heat to crystallize. In the case of pressurizing in this crystallization step, the pressurization up to 6 atm is for simultaneously expressing crystallization and high purification, and even if pressurizing at a pressure higher than 6 atm, the effect is not significantly improved. . Regarding the crystallization temperature, if it is lower than 80 ° C., the crystallization speed becomes too slow, and it takes a long time for crystallization.
Even if heated above ℃, the crystallization rate does not increase. Further, regarding the crystallization time, if it is less than 1 hour, the crystallization becomes insufficient and the quality is deteriorated. On the contrary, even if it exceeds 10 hours, the crystallization effect does not change. Ions are occluded in the crystal and cause quality deterioration.

The crystallized product of the crystalline antimony pentoxide hydrate thus treated in the crystallization step is then subjected to a pH of 1 with ammonia gas or ammonium carbonate, if desired, before being washed in the washing step. It is adjusted to ˜6 to neutralize the hydrochloric acid content dissolved in the crystallized product. This pH
By adjusting, it is possible to further reduce the concentration of chlorine ions occluded in the produced crystalline antimony pentoxide hydrate, and in particular to obtain an antimony pentoxide hydrate useful for applications where the anion concentration needs to be reduced. Obtainable.

Next, the crystallized product is filtered in a washing step,
The washing is repeated several times. This washing treatment is usually carried out until the electric conductivity of the filtrate becomes several 100 μs / cm or less, more preferably 50 μs / cm or less. The water used for this washing treatment has an electric conductivity of 5 ° C or lower and an electric conductivity of 5 ° C or lower.
Pure water of μs / cm or less is preferable, and an appropriate method such as vacuum filtration, pressure filtration, or centrifugation is adopted as the filtration method.

The crystalline crystalline antimony pentoxide hydrate obtained through the above washing step is then heated to 105 to 200 ° C., preferably 110 to 150 ° C., in order to remove adhering water.
Dry at 5 ° C. for 5 to 15 hours, preferably 8 to 12 hours. In this case, when the temperature exceeds 200 ° C., the water of crystallization is dehydrated and the ion exchange capacity is lowered, which is not preferable. The resulting agglomerate is then for example a pin disc mill,
It is crushed with a crusher such as a ball mill or a jet mill, and sieved to 325 mesh (44 μm) or less using a classifier such as a micron shifter, and primary particles of 0.1 to 0.1 are obtained.
A crystalline antimony pentoxide hydrate having a particle size of 0.5 μm and a particle size of 0.5 to 44 μm is obtained as a product.

[0016]

When liquid antimony pentachloride is directly hydrolyzed in one step, the reaction rapidly progresses to generate hydrogen chloride gas, which often requires exhaust gas treatment equipment. However, in the method of the present invention, since hydrolysis of antimony pentachloride is carried out in two steps without using alkali,
This hydrolysis reaction proceeds slowly, and a uniform hydrolysis product with a narrow particle size distribution can be obtained, whereby the particle shape is spherical and the size is uniform, and there are no newly added cations. It is considered that a highly pure crystalline antimony pentoxide hydrate with a low concentration of occluded chlorine ions etc. can be obtained. Further, the decomposition stability of the liquid when the partial hydrolyzed liquid is stored is good, and is preferable in terms of operation safety.In addition, in the method of the present invention, the hydrolysis product of antimony pentachloride is heat-treated, particularly Crystallization and high purification proceed at the same time by heat treatment under pressure, so that a crystalline antimony pentoxide hydrate having a high cation exchange capacity can be obtained.

[0017]

EXAMPLES The method of the present invention will be specifically described below based on Examples and Comparative Examples.

Example 1 Antimony trichloride was produced by reacting metal antimony with chlorine, and the antimony trichloride was purified by distillation to have a purity of 99.99% by weight and a radioactive element content of 0.5 ppb or less. Got This antimony trichloride is dissolved in pure water at 30 ° C. to prepare an aqueous solution having an antimony trichloride concentration of 90% by weight. In this aqueous solution, an amount of 1.05 times the stoichiometric equivalent to antimony trichloride is prepared. Chlorine was introduced at 30 ° C. by introducing chlorine gas. Generation of hydrogen chloride gas was not observed during this chlorination reaction.

70 ml of ion-exchanged water was added to the antimony pentachloride aqueous solution (200 g / water 17 ml) thus obtained.
(Weight ratio of 0.35) was added, and the mixture was stirred at room temperature for 30 minutes for partial hydrolysis. The resulting reaction solution for the partial hydrolysis reaction was transparent and light yellow. The total amount of the reaction solution obtained by the partial hydrolysis reaction was added to 1,800 ml of pure water kept at 60 ° C. in a reflux reactor over 30 minutes, and stirred for 30 minutes to carry out the partial hydrolysis reaction. The product was completely hydrolyzed. The reaction solution of the complete hydrolysis reaction obtained was in the state of a white slurry.

Next, the obtained reaction solution for the complete hydrolysis reaction was heated to 85 ° C. as it was, and was kept under reflux for 2 hours for crystallization treatment, and then cooled to 60 ° C. The obtained crystallized product was in a state like a colloidal solution. Therefore, this crystallized product was vacuum filtered to remove the dissociated hydrochloric acid content to obtain crystalline antimony pentoxide hydrate.

About this crystalline antimony pentoxide hydrate, washing water 75 having an electric conductivity of 1.0 μs / cm at 25 ° C.
The repulp was washed 6 times using 0 ml / time, and vacuum filtration was performed to obtain a washed crystalline antimony pentoxide hydrate. The electrical conductivity of the filtrate obtained during the sixth repulp washing was 120 μs / cm. The crystalline antimony pentoxide hydrate thus obtained was placed in a box dryer,
It was dried at 105 ° C for 10 hours, then crushed in a mortar and sieved with a 325-mesh vibrating screen to obtain 108 g of antimony pentoxide hydrate as a product from the bottom of the sieve.

Regarding the antimony pentoxide hydrate thus produced, the residual chloride ion concentration (ppm), the residual radioactive element concentration (ppb), the particle size of the primary particles (μm),
Secondary particle size (μm), particle shape, cation exchange capacity (Na ⁺ , meq / g), Sb ₂ O ₃ content (wt%), specific surface area (m ² / g), amount of adhering water (weight) %) And sodium ion concentration (Na ⁺ , ppm) were measured. The results are shown in Table 1. The residual chlorine ion concentration is
Using 100 ml of ultrapure water for 10 g of sample,
Hot water extraction was performed under the conditions of 0 ° C. for 20 hours, and the chlorine ion concentration in the extract was measured using ion chromatography. The particle size of the secondary particles is determined by measuring the average particle size during 1 minute of ultrasonic treatment using a laser particle size distribution analyzer [trade name: SK Laser PRO-7000S manufactured by Seishin Enterprise Co., Ltd.]. It was Also,
The primary particle size was determined by observing a photograph with a scanning electron microscope. Furthermore, regarding the cation exchange capacity,
Prepare a NaCl standard solution containing 1 meq (milliequivalent) each of sodium ion (Na ⁺ ) and chloride ion (Cl ⁻ ) in 1 ml, dilute it with a specified amount of pure water, and add exactly to this solution. Add 30 g of the weighed sample,
After stirring at room temperature for 24 hours, this was filtered through a 0.2 μm membrane filter, and the filtrate was collected and a part thereof was collected and analyzed by atomic absorption spectrometry for sodium ion (N
a ⁺ ) was measured, and the ion-exchanged value was calculated from the result.

Example 2 The reaction solution of the complete hydrolysis reaction obtained by the same method as in Example 1 was heated to 85 ° C. as it was and held for 2 hours, and then vacuum filtered, and the obtained cake was purified water. The mixture was dispersed in the above to obtain a 15 wt% slurry, which was placed in an autoclave for crystallization treatment under the conditions of 3 atm and 120 ° C. for 5 hours, and then cooled to 60 ° C. Next, the obtained crystallized product was washed 6 times with repulp as in Example 1, and the electric conductivity of the filtrate at that time was 1
Although it was 0 μs / cm or less, vacuum filtration was performed to obtain crystalline antimony pentoxide hydrate. Drying and sieving were carried out in the same manner as in Example 1 to obtain antimony pentoxide hydrate 1 as a product.
10 g were obtained. The characteristics of the obtained antimony pentoxide hydrate were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 3 194.8 g of antimony trichloride having a purity of 99.99% by weight and a radioactive element content of 0.5 ppb or less obtained by purifying by distillation in the same manner as in Example 1 above was added with 30% by weight of hydrochloric acid 42
It was dissolved in 5.6 g to prepare a 31.4 wt% antimony trichloride / hydrochloric acid solution, and 1.1 times the stoichiometric amount of chlorine gas was added to this hydrochloric acid solution. It was introduced and chlorinated at 50 ° C. A hydrochloric acid solution containing 37.5% by weight of the obtained antimony pentachloride was added to 600 ml of ion-exchanged water at 25 ° C. with stirring, and partial hydrolysis was carried out for 1 hour. Next, 3,400 ml of pure water was added to the reaction solution obtained by this partial hydrolysis reaction at 30 ° C.
Was added over 1 hour, and after completion of the addition, stirring was continued for 30 minutes at the same temperature to carry out complete hydrolysis. After completion of this complete hydrolysis, the reaction mixture was centrifuged, and the obtained complete hydrolysis product was added again to pure water to prepare a 15 wt% slurry. This slurry was placed in an autoclave, crystallized under the conditions of 3 atm and 120 ° C. for 4 hours, then cooled to 50 ° C. and centrifuged. The obtained crystallized product was washed 6 times with 600 ml of washing water in the same manner as in Example 1 to make the electric conductivity of the filtrate 100 μs / cm or less. Then, vacuum filtration was performed to obtain a crystalline antimony pentoxide hydrate. The characteristics of the crystallized product thus obtained were measured. The results are shown in Table 1.

Example 4 Before repulp washing after completion of the crystallization treatment, ammonia gas was blown into the crystallization-treated product at 30 ° C. until the pH of the crystallization-treated product reached 9.0 for neutralization treatment. 75 g of crystalline antimony pentoxide hydrate was obtained in the same manner as in Example 3 except that conditioning was performed using a 0.1 N nitric acid aqueous solution in a washing step performed using washing water. It was The properties of the obtained antimony pentoxide hydrate were measured. The results are shown in Table 1.

Comparative Example 1 Antimony pentachloride (aqueous solution) obtained in the same manner as in Example 1.
185 g of water was kept at 30 ° C in 1,800 ml of pure water.
It was added over 0 minutes and completely hydrolyzed in one step, but the decomposition reaction proceeded violently while generating white smoke, and vitreous antimony pentoxide hydrate was produced. After that, crystallization treatment, repulp washing treatment, and drying treatment under the same conditions as in Example 1 were performed. The properties of the obtained antimony pentoxide hydrate were measured. The results are shown in Table 1. As shown in Table 1, when the hydrolysis was carried out in a single stage without partial hydrolysis, the hydrolysis proceeded non-uniformly, and even if the crystallization treatment was carried out thereafter, it was amorphous and crystalline. It turns out that you can only get a mixture of the ones.

Comparative Example 2 96 g of crystalline antimony pentoxide hydrate was obtained in the same manner as in Example 3 except that the crystallization treatment was changed to an autoclave treatment and the mixture was kept at 30 ° C. for 24 hours while stirring. The properties of the obtained antimony pentoxide hydrate were measured. The results are shown in Table 1. As a result of Table 1, in Comparative Example 2, since the crystallization temperature is as low as 30 ° C., the crystallization of the produced antimony pentoxide does not proceed, it stops in the amorphous state, the impurity content is large, and the ion exchange capacity is also large. It turns out to be low.

[0028]

[Table 1]

[0029]

INDUSTRIAL APPLICABILITY According to the present invention, the cation exchange capacity is as high as 1.7 to 3.2 meq / g, the residual anion impurity concentration is also low, and the average particle size of crystalline antimony pentoxide hydrate is high. 0.5-44 μm, specific surface area 7-35 m
A high-purity antimony pentoxide hydrate that can be obtained at a mass ratio of ² / g and that can be mass-produced and that is suitable for an industrial process can be produced. A highly pure crystalline antimony pentoxide hydrate, which is useful as a resin filler used as a flame retardant for a flame retardant resin and has excellent dispersibility, can be advantageously produced.

Claims (3)

[Claims] 1. A chlorination step in which antimony trichloride is chlorinated to give antimony pentachloride, and the obtained antimony pentachloride is mixed with water / antimony pentachloride in a weight ratio (H ₂ O / SbC).
₁₅ ) A partial hydrolysis step in which 0.15 to 1 of water is added to carry out partial hydrolysis, and the obtained partial hydrolysis product is produced, and the amount of water is 10 to 50 times the volume of antimony pentachloride. The complete hydrolysis step of completely hydrolyzing with, and the obtained hydrolysis product at 80 to 150 ° C. and 1 to 80 ° C. under normal pressure or pressure.
A crystallization step of heating and crystallization under the condition of 10 hours;
A washing step of washing the obtained crystallized product, the method for producing an antimony pentoxide hydrate. 2. The method for producing an antimony pentoxide hydrate according to claim 1, wherein the crystallization step is performed under a pressure of 1.5 to 6 atmospheres. 3. The method for producing an antimony pentoxide hydrate according to claim 1, wherein the washing step is carried out until the obtained crystallized product has an electric conductivity of the filtrate of several 100 μs / cm or less.