JPS5932406B2 - Method for producing antimony trichloride from antimony trisulfide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for economically producing high purity antimony trichloride from ores containing antimony compounds, particularly antimony sulfide.

According to the method of the invention, antimony trichloride of high purity can be obtained even when ores containing large amounts of impurities are processed.

The production of high-purity antimony trichloride is necessary for the production of high-purity antimony trioxide, which is used, for example, as a flameproofing additive in the plastics industry and as a white pigment.

These uses require high purity antimony trioxide and are free from the common impurities of antimony sulfide, such as arsenic, lead,
There shall be no zinc, copper, silver, etc.

In classical antimony trioxide production methods, these impurities tend to be entrained by and impure the antimony trioxide formed.

The process of the present invention avoids the entrainment of these impurities and can produce high purity antimony trioxide without excessive industrial expense.

It is known that antimony sulfide reacts with hydrogen chloride at room temperature (Gmelins Handbuchde
r anorganischen Chemie, No.
, 18, Part B, p. 409 (1949)).

In this case, however, the antimony trichloride formed envelops the solid antimony sulfide and the reaction soon stops.

Furthermore, it is known that antimony sulfide dissolves in hot concentrated hydrochloric acid solutions forming hydrogen sulfide and antimony trichloride (Handbuch analysis-cher.
Chemie, 6th edition, volume 1, page 427, Lei-
pzig, 1867).

However, the latter method has some significant drawbacks inherent in the industrial implementation of the method.

For example, the three-component system 5bCA! Separation of 3-HCl-H2O is problematic.

The strong corrosive action of hot hydrochloric acid solutions requires the use of expensive corrosive materials.

Furthermore, water removal requires high energy consumption.

Furthermore, it is known to suspend antimony sulfide in the form of gray antimony ore in concentrated hydrochloric acid and treat it with chlorine so that the sulfur is precipitated as elemental sulfur and thus no hydrogen sulfide is formed (West German patent No. 430614).

However, concentrated hydrochloric acid suspension and the supply of elemental chlorine remain disadvantageous.

Furthermore, difficulties arise in the separation of colloidal sulfur.

Another method for producing antimony trichloride consists in reacting gray antimony ore with phosgene at about 400° C. (Belgium Patent No. 451,513).

Apart from the dangerous and disadvantageous use of phosgene, the resulting antimony trichloride must be condensed at such high temperatures that the arsenic trichloride that also forms does not yet separate.

It is often necessary to separate arsenic trichloride and antimony trichloride by fractionation of crude chloride mixtures.

DE 2207181 describes a method for producing antimony compounds.

According to this, a stibnite-containing ore is extracted with an aqueous ammonium sulfide solution, and then this extraction solution is oxidized with sulfuric acid.

Antimony chloride cannot be produced by this method.

Furthermore, impurities which are also soluble in ammonium sulfide may also enter the product.

French Patent No. 2153422 states that the temperature
It is described that antimony sulfide is reacted with anhydrous hydrogen chloride at 350°C.

In this case, antimony trichloride and hydrogen sulfide are removed together from the reaction zone and separated from each other by condensation.

However, since the reaction to form antimony trichloride from antimony sulfide and hydrogen chloride is an exothermic reaction, most of the introduced hydrogen chloride gas is either lost without reaction or must be purified and recycled at great expense. It won't happen.

The fact that 60% of the hydrogen chloride used does not react
making economical use of the method impossible.

In addition, the condensate also contains sulfide due to the establishment of equilibrium.

Therefore, the known technology for producing antimony trichloride shows in principle three basic methods, namely the first method is a difficult and expensive three-component system (Sb(J'3-HC7-H2O
), the second method proceeds with the use of oxidizing agents, for example the change of charge is carried out with the use of chlorine and sulfur monochloride, and the third method proceeds in the gaseous state at elevated temperatures. Progressing, for example, the formula: Sb2S3+6HC4-2S
The method represented by bC13+3H2S is reversible, and the reverse reaction becomes stronger as the temperature increases.

It was therefore an object of the present invention to provide a process for producing high-purity antimony trichloride with good yields, in which case antimony compounds, such as antimony sulfide, impure antimony oxide, and especially high lead and arsenic contents It is possible to start from a sulfide ore with

The description “antimony sulfide” refers to mixed metal sulfide and Sb2
shall represent all antimony sulfides, including sulfides with formulas other than S3, and all ores and concentrates containing such sulfides.

This problem is solved according to the invention by carrying out the reaction of antimony sulfide with gaseous hydrogen chloride in a homogeneous phase, in a non-aqueous solvent suitable for all reaction components, at a temperature below the boiling point of antimony trichloride. be done.

Surprisingly, it was discovered that antimony trichloride, which can be melted, is a solvent for antimony sulfide.

Therefore, the reaction can proceed in a homogeneous phase due to the equally good dissolution of hydrogen chloride gas in the molten antimony trichloride.

Preferably the solvent is antimony trichloride and the temperature is between 73 and 2
In the range of 23°C, especially 80°C.

In embodiments of the invention, the reaction can also be carried out at a pressure of 1 to 10 bar.

Organic solvents such as penzole or chlorinated hydrocarbons are also suitable as solvents.

In particular, using antimony trichloride as the solvent and at 80°C
At nearby reaction temperatures, the reaction quickly reaches equilibrium.

That is, when gaseous hydrogen chloride is introduced into a solution of antimony sulfide and antimony trichloride at a temperature where antimony trichloride exists in a liquid state, this hydrogen chloride similarly dissolves in antimony trichloride, and the dissolved antimony sulfide reacts immediately with the liberation of gaseous hydrogen sulfide.

Antimony sulfide is advantageously used in extremely fine particle size,
This not only results in better and faster dissolution, but also
Above all, a good dispersion of the still undissolved antimony sulfide in the molten antimony trichloride is obtained.

The particle size of the antimony sulfide is up to 1rILrft (i.e. starting from very fine dust-like substances up to particle sizes of 1i7!m), preferably up to 150μ (1μm10−
6m).

The solubility of antimony sulfide in antimony trichloride at 80°C is about 2.15 weight coefficients, so antimony sulfide is added to liquid antimony chloride, especially 0.2 to 0 parts by weight of antimony sulfide to 1 part by weight of antimony trichloride. Advantageously, it is suspended in an amount of .4 parts by weight.

According to the invention, the solvent antimony trichloride for the reaction can be replaced by an organic solvent such as, for example, penzole, doluol or a chlorinated hydrocarbon, such as carbon tetrachloride or trichloroethane.

The reaction is preferably carried out in one or more tower reactors connected one after the other, which may be made of glass, for example, and are surrounded on the outside by heating devices.

The reactor contains suitable fittings for good distribution and thorough mixing of the hydrogen chloride introduced from below.

The generated reaction gas, which contains hydrogen sulfide and an amount of hydrogen chloride corresponding to the reaction equilibrium at the temperature used, is absorbed into a suitable storage tank.

After the reaction has ended, as evidenced by the fact that the reaction gas no longer contains hydrogen sulfide, the antimony trichloride formed is separated from the reaction mixture by any method known in the art, for example by filtration or distillation.

If a suitable distillation is chosen for the separation of antimony trichloride, highly pure antimony trichloride is obtained, which can be sold or further processed without work-up.

For example, when hydrolyzing to give antimony oxide, a large amount of pure water is advantageously dissolved in the distillation condensate, which is still in liquid form, so that the concentration of water in the resulting solution is between 5 and 8%.
Make it.

In this way, solidification of the high-purity antimony trichloride added dropwise is avoided, and the subsequent hydrolysis, for example with aqueous ammonia solution, can advantageously be carried out at room temperature.

The method for producing high-purity antimony trichloride described above is simple by continuously feeding antimony sulfide to the top of the first tower reactor and taking out the reaction product from an appropriate point in the last reactor. The method can be carried out continuously.

The advantages obtained with the process according to the invention are, inter alia, without the use of high temperatures, without expensive corrosion-resistant materials and without energy-consuming distillation to separate out water that does not take part in the actual reaction.
The reaction of converting antimony sulfide to antimony trichloride can be carried out in a simple manner in one step.

Next, examples of the method of the present invention will be described.

Example 1 800 parts by weight of antimony chloride was melted in a double-walled container equipped with a stirrer and a thermometer and temperature-controlled at 80° C. with hot water.

Antimony sulfide (97.5% 5b2S3) is contained in this melt.
250 parts by weight were suspended and a stream of dry 7 gas was passed through the suspension for 400 minutes.

The reaction gas was washed with water and then absorbed into 15 g of caustic soda solution.

After completion of the reaction, 163 g of sodium sulfide were found in the storage tank, corresponding to 97 parts of the amount of sulfur charged as antimony sulfide.

Example 2 Five tower-like double-walled reactors were connected in series and temperature-controlled to 80° C. by means of a heating liquid circulated through a heating jacket.

In each reactor, 160 parts by weight of antimony chloride was melted, and 64 parts by weight of antimony sulfide were suspended in the melt.

A dry HCl gas flow of 2.61/min was introduced and, after completion of the reaction, the contents of the reactor were carefully separated by filtration.

Analysis of the solid residue yielded an antimony content of 1.966 parts by weight, corresponding to 1.055 parts by weight of the antimony sulfide used.

Corresponding results are obtained if, for example, ground and dried ores having a weight ratio of antimony sulfide of 50.4% are reacted in the apparatus described.

Example 3 26 parts by weight of antimony sulfide are mixed with 120 parts by weight of antimony chloride in a pressure vessel whose temperature is adjusted to 80° C. with a suitable heating liquid.
Parts by weight were suspended.

A stream of dry H(l) gas was introduced into this suspension under a pressure of 6 bar.

The reaction gas leaving the autoclave, consisting of hydrogen sulfide and hydrogen chloride, contained 62 to 64 parts by volume of H2S under the reaction conditions.

Example 4 In a reactor as in Example 1, 80 parts by weight of antimony sulfide were each suspended in 400 parts by weight of antimony chloride and reacted with a stream of dry H(l) gas.

In this case, the reaction gases were investigated by varying the reaction temperature each time, keeping all other conditions constant.

In this case, for example, the following H2S concentration was observed: 93.
5°C: 36.0% by volume H2S 135.0°C: 24.7% by volume H2S 173.8°C: 13.0% by volume H2S 213.5°C: 1.4% by volume H2S temperature and its belonging The H2S volume % values indicate that as the temperature increases, the reaction becomes progressively worse or increasingly reversible towards the formation of antimony trichloride, as already mentioned above.

If the working conditions require working at temperatures of the order of 150 or 170° C., it is advantageous to work under pressure in order to still obtain reasonable yields.

Claims (1)

[Scope of Claims] 1. A method for producing antimony trichloride from antimony trisulfide by reacting antimony trisulfide with gaseous hydrogen chloride under the supply of heat, wherein the reaction is carried out in a homogeneous phase and all the reaction components are reacted. 1. A method for producing antimony trichloride from antimony trisulfide, which is carried out in a suitable non-aqueous solvent at a temperature below the boiling point of antimony trichloride. 2. The method according to claim 1, wherein the non-aqueous solvent is antimony trichloride. 3. Process according to claim 1 or 2, wherein the reaction is carried out at a temperature of 73 to 223°C, in particular 80°C. 4. Process according to claim 1 or 2, wherein the reaction is carried out at a pressure of 1 to 10 bar. 5. The method of claim 1, wherein the solvent is an organic solvent such as penzole or a chlorinated hydrocarbon. 6. The method according to claim 1, characterized by antimony sulfide having an extremely fine particle size.