RU2288169C2 - Sodium hydrosulfide production process - Google Patents

Abstract

FIELD: industrial inorganic synthesis.

SUBSTANCE: invention is directed to production of sodium hydrosulfide, which is widely used as reducing agent in chemical processes, as corrosion inhibitor in production of soda ash and sodium bicarbonate, for production of polysulfide plastics, in paper-and-pulp industry, mining, and leather industry. Process comprises reaction of sodium hydroxide with hydrogen sulfide, wherein hydrogen sulfide source is gas obtained during decomposition of barium sulfide by treating barium sulfide pulp containing 30% BaS with sulfuric acid atBaS/H₂SO₄ ratio 1.0:(1.0-1.2). Thus obtained barium sulfate is separated from liquid phase by filtration, whereupon barium sulfate is subjected to reductive firing at 900-1200°C to produce barium sulfide melt, which is leached with water to produce barium sulfide pulp. The latter is returned into sulfuric acid treatment stage.

EFFECT: reduced expenses on raw material, lowered explosion risk, and avoided use of expensive catalysts.

5 cl, 2 tbl, 4 ex

Description

The scope of the invention is the chemical industry, in particular the production of sulfide-containing compounds. Sodium hydrosulfide is widely used as a reducing agent in chemical processes, as a corrosion inhibitor in the production of soda ash and sodium bicarbonate, for the production of polysulfide plastics, in the pulp and paper, mining and leather industry.

A number of methods for producing sodium hydrosulfide are known.

The classical method of producing sodium hydrosulfide is based on the interaction of sodium hydroxide with hydrogen sulfide-containing gases from oil refining and coke plants:

NaOH + H ₂ S → NaHS + H ₂ O

These gases, however, contain a significant amount of impurities, which leads to a decrease in the quality of the resulting product and an increase in the consumption of sodium hydroxide, and preliminary purification of hydrogen sulfide requires sophisticated equipment and leads to a significant increase in costs.

A solution of sodium hydrosulfide can be obtained by the interaction of hydrogen sulfide with a solution of Na ₂ CO ₃ [US No. 2376433, IPC 01 01 17/32].

However, this results in a solution with a high content of sodium bicarbonate, since the process proceeds according to the following reaction:

Na ₂ CO ₃ + H ₂ S → NaHS + NaHCO ₃

In addition to the need for purification from sodium bicarbonate, the method has other disadvantages:

1. Up to half of the consumed sodium carbonate is consumed in a side reaction with the formation of sodium bicarbonate;

2. The relatively low solubility of sodium carbonate in water does not allow the absorption process to be intensive enough, which creates technological difficulties in industrial production, and also leads to the formation of dilute solutions of sodium hydrosulfide.

Another way to obtain sodium hydrosulfide is the absorption of hydrogen sulfide by a solution of sodium sulfide [US No. 4439411, IPC C 01 In 17/32, 1981].

The process proceeds according to the following reaction:

Na ₂ S + H ₂ S → 2NaHS

Thus obtained sodium hydrosulfide may be of sufficient purity, however, due to the high cost of sodium sulfide, this method is not effective.

In addition, all of the above methods are tied to sources of hydrogen sulfide, since the extreme toxic hazard of hydrogen sulfide does not allow transporting significant amounts of hydrogen sulfide to any significant distances.

NaHS solutions with a concentration of up to 385 g / l can be obtained by the interaction of dry soda ash with calcium hydrosulfide [Pozin M.E. The technology of mineral salts. T1. L .: Chemistry, 1974, p.500] in accordance with the following reaction scheme:

Ca (HS) ₂ + Na ₂ CO ₃ → 2NaHS + CaCO ₃

The disadvantage of this method is the need for preliminary production of calcium hydrosulfide, an expensive and scarce raw material.

More concentrated solutions of sodium hydrosulfide (50%) can be obtained by the action of hydrogen sulfide on solid sodium sulfide at a temperature of 80-90 ° C [Pozin M.E. The technology of mineral salts. T1. L .: Chemistry, 1974, p.501] in accordance with the following reaction:

Na ₂ CO ₃ + 2H ₂ S → 2NaHS + 2H ₂ O

while the mass melts and a solution of sodium hydrosulfide is formed.

Although this method can be called highly effective, it is associated with great difficulties in obtaining pure hydrogen sulfide.

Also known is a method of producing sodium hydrosulfide, based on the interaction of metallic sodium with hydrogen sulfide in an ethanol medium [Guide to inorganic synthesis. Ed. G. Brower. M., "World", t.2, 1985, p.406].

A known method of producing sodium hydrosulfide by the interaction of hydrogen sulfide released during the processing of iron sulfide with hydrochloric acid, and sodium ethylate obtained by the interaction of metallic sodium with absolute ethanol [Workshop on inorganic chemistry. Under. ed. Zlomanova. M .: Moscow State University, 1994].

In industrial conditions, these methods are practically not applicable due to the use of explosive and combustible substances - absolute alcohol, sodium metal, a complex technological scheme, and the high cost of the resulting product.

The closest technical solution to the claimed invention is a method for producing sodium hydrosulfide [JP No. 63139007, IPC With 01 17/22, publ. 06/10/1988], including the absorption of hydrogen sulfide by a solution of sodium hydroxide, where the reaction between vapors of high-purity sulfur and high-purity hydrogen is used at a temperature of 250-500 ° C and a pressure of 0.1-10 kg / cm ² in the presence of cobalt-molybdenum or nickel -molybdenum catalyst on an aluminum carrier.

This method has the following disadvantages:

1. The need to use high purity sulfur and hydrogen in the process;

2. High explosiveness of processes associated with the use of hydrogen;

3. The high cost of the raw materials and catalysts used;

4. The attachment of production to a source of hydrogen.

The objective of the invention is to reduce the cost of the process of producing sodium hydrosulfide, reduce its cost, select the most affordable, cheap feedstock, widely used in the chemical industry.

The specified technical problem of producing sodium hydrosulfide is solved by the interaction of sodium hydroxide with hydrogen sulfide, and hydrogen sulfide and barium sulfate are preliminarily obtained by decomposition of barium sulfide by treating barium sulfide pulp with sulfuric acid at a molar ratio of BaS to H ₂ SO ₄ equal to 1.0: 1.0-1 , 2, the obtained barium sulfate is separated from the liquid phase by filtration, then barium sulfate is subjected to reduction firing at a temperature of 900-1200 ° C to obtain a barium sulfide melt, which is leached with water to obtain bullets s barium sulfide obtained in the leaching stage, the pulp is recycled to the barium sulfide with sulfuric acid processing.

The method is as follows:

The pulp or clarified solution of barium sulfide at an initial concentration of 15-25 wt.%, Treated with sulfuric acid at a concentration of 10-96 wt.%, While receiving hydrogen sulfide and barium sulfate:

BaS + H ₂ SO ₄ → BaSO4 + Н ₂ S

The resulting hydrogen sulfide is absorbed by a solution of sodium hydroxide in packed columns according to the total reaction equation:

H ₂ S + NaOH → NaHS + H ₂ O

A solution of sodium hydrosulfide is removed from the process when a pH of 8 ÷ 10 is reached in the production column. The insoluble barium sulfate formed as a result of the interaction of barium sulfide with sulfuric acid after neutralization of the reaction mixture is separated from the liquid phase, dried and, if necessary, subjected to re-firing. The need for drying can be caused by a high moisture content, which impedes the transportation of the obtained barium sulfate or violates the regime of other technological operations.

Reductive firing of precipitated barium sulfate is carried out at a temperature of 900-1200 ° C (for example, in a rotary kiln), as a result, a barium sulfide melt is formed, which is ground and leached.

As a reducing agent, either coal, or coke, or petroleum coke, or coke breeze, hydrogen, carbon monoxide (II), natural gas or its components are used. In this case, depending on the reducing agent used, the following reactions proceed:

BaSO ₄ + 2C → BaS + 2CO ₂

BaSO ₄ + 4H ₂ → BaS + 4H ₂ O

BaSO ₄ + 4CO → BaS + 4CO ₂

BaSO ₄ + CH ₄ → BaS + CO ₂ + 2H ₂ O

The barium sulfide pulp obtained in the leaching stage is returned to the treatment with sulfuric acid.

Since impurities are introduced with the raw material, as the process proceeds, sludge may accumulate, consisting of insoluble compounds of calcium, silicon and other impurities resulting from side reactions.

Sludge from the process is removed continuously or periodically as it accumulates. To remove sludge from the process after the leaching stage, sedimentation and filtration of barium sulfide pulp is carried out. The sedimentation and filtration is carried out at a temperature of 50-95 ° C, which allows the use of more concentrated solutions of BaS, and also prevents the crystallization of barium sulfide in technological equipment and reduces its loss with sludge.

Periodic sludge removal can also be performed after treating the pulp with sulfuric acid, however, in this case, barium losses with sludge increase.

The use of gas and petroleum coke with low ash content as reducing agents reduces the amount of sludge generated and requiring removal and, accordingly, loss of barium in the form of unreduced barium sulfate, BaCO ₃ , BaSiO ₃ , BaS ₂ O ₃ , BaSO ₃ and other water-insoluble barium salts.

Minor losses of barium with the mother liquor in the form of fine particles of BaSO ₄ can occur during filtration.

The total losses of barium are insignificant (especially when using raw materials with a small fraction of impurities) and are compensated by the introduction of fresh barium sulfate at the stage of reduction firing.

The following are examples of the method of producing sodium hydrosulfide.

Example 1

A barium sulfide pulp obtained by leaching a barium sulfide melt with a BaS content of 89% water in a molar ratio of BaS: water equal to 1.0: 4.0 is treated with sulfuric acid in a molar ratio of BaS: H ₂ SO ₄ equal to 1.0: 1 , 2, the resulting hydrogen sulfide is absorbed by a 42% sodium hydroxide solution. The result is a solution of sodium hydrosulfide A. The resulting precipitate of barium sulfate is filtered off, dried and reduced at a temperature of 1000 ° C with coke. The resulting melt with an average BaS content of 92.3% is leached with water in a ratio of 1: 4, then treated with sulfuric acid, the resulting hydrogen sulfide is absorbed with a 42% sodium hydroxide solution. The result is a solution of sodium hydrosulfide B.

The experiments were carried out using sulfuric acid with a concentration of 10, 30, 50, 92.5, and 96% with a stoichiometric ratio of reagents and with an excess of sulfuric acid of 5, 10, 20%.

The results of the experiments are presented in tables 1, 2.

In all cases, the obtained solutions of sodium hydrosulfide, both A and B, for all indicators met the requirements of regulatory and technical documentation - TU 301-06-26-90 and corresponded to the indicators provided for sodium hydrosulfide technical grade 1.

As practice has shown, when using coal or petroleum coke as a reducing agent, the quality indicators of the sodium hydrosulfide obtained remained at the same level and corresponded to the TU 301-06-26-90 indicators provided for technical grade 1 sodium hydrosulfide.

Example 2

A barium sulfide pulp obtained by leaching a barium sulfide melt with a BaS content of 89% water in a molar ratio of BaS: H ₂ SO _{4 of} 1: 4 is treated with sulfuric acid in a molar ratio of BaS: H ₂ SO _{4 of} 1.0: 1, 0, the resulting hydrogen sulfide absorb 42% sodium hydroxide solution. The result is a solution of sodium hydrosulfide concentration of 30.7%. The resulting precipitate of barium sulfate is filtered off, dried and reduced at a temperature of 1100 ° C with natural gas. The resulting melt with an average BaS content of 96.4% is leached with water in a ratio of 1: 4, then it is treated with sulfuric acid, the resulting hydrogen sulfide is absorbed with a 42% sodium hydroxide solution. The result is a solution of sodium hydrosulfide concentration of 31.8%.

Example 3

A barium sulfide pulp obtained by leaching a barium sulfide melt with a BaS content of 89% water in a ratio of 1: 3 is treated with sulfuric acid in a molar ratio of BaS: H ₂ SO ₄ equal to 1.0: 1.2, the resulting hydrogen sulfide is absorbed in a 42% hydroxide solution sodium. The result is a solution of sodium hydrosulfide concentration of 31.1%. The resulting precipitate of barium sulfate is filtered off, dried and reduced at 900 ° C with hydrogen. The resulting melt with an average BaS content of 96.5% is leached with water in a ratio of 1: 4, then treated with sulfuric acid, the resulting hydrogen sulfide is absorbed with a 42% sodium hydroxide solution. The result is a solution of sodium hydrosulfide concentration of 32.1%.

Example 4

A barium sulfide pulp obtained by leaching a barium sulfide melt with a BaS content of 89% water in a ratio of 1: 5.5 is treated with sulfuric acid in a molar ratio of BaS: H ₂ SO ₄ equal to 1.0: 1.1, the resulting hydrogen sulfide is absorbed 42% sodium hydroxide solution. The result is a solution of sodium hydrosulfide concentration of 30.8%. The precipitate of barium sulfate is filtered off, dried and reduced at a temperature of 1200 ° C with carbon monoxide (II). The resulting melt with an average BaS content of 96.1% is leached with water in a ratio of 1: 4, then treated with sulfuric acid, the resulting hydrogen sulfide is absorbed with a 42% sodium hydroxide solution. The result is a solution of sodium hydrosulfide concentration of 31.7%.

As can be seen from the above examples, when firing precipitated barium sulfate, the degree of reduction increases slightly, which leads to a slight increase in the average concentration of NaHS. This is due to a decrease in the proportion of impurities in the hydrogen sulfide-containing gas, in particular СО ₂ , which, accordingly, leads to a decrease in the content of Na ₂ S and Na ₂ CO ₃ in the finished product, which are formed during the occurrence of side reactions:

CO ₂ + 2NaOH → Na ₂ CO ₃ + H ₂ O

H ₂ S + 2NaOH → Na ₂ S + 2H ₂ O

Thus, the above examples show that the proposed method allows to obtain high-quality sodium hydrosulfide, using more available sulfuric acid and sodium hydroxide as starting materials.

It is also seen that the use of gaseous reducing agents makes it possible to obtain sodium hydrosulfide solutions with a higher NaHS concentration compared to solid reducing agents (coal, coke, petroleum coke).

The proposed method in comparison with the prototype has the following advantages:

1. The raw materials used are inexpensive and widely available;

2. The process has a lower explosion hazard;

3. Production is not tied to a source of pure hydrogen;

4. There is no need to use expensive catalysts.

A feature of the method is the autonomous production of hydrosulfide, not tied to sources of hydrogen sulfide.

table 2
Solution B Analysis Results The concentration of sulfuric acid,% The ratio of H ₂ SO ₄ : BaS (mol) 1: 1 1: 1.05 1: 1,1 1: 1.2. Mass fraction of components in solution,% NaHS Na ₂ S Na ₂ CO ₃ NaHS Na ₂ S Na ₂ CO ₃ NaHS Na ₂ S Na ₂ CO ₃ NaHS Na ₂ S Na ₂ CO ₃ 10 30.3 0.4 0.9 31.9 0.1 0.2 31.9 0.8 0.2 31.8 1,0 0,0 thirty 30.1 1.3 0,0 31.9 0.1 0.1 31.6 0.2 0.6 31.3 0.7 0.5 fifty 30.1 0.3 1.4 31.7 0.2 0.5 31.1 0.7 0.8 31.3 1,0 0,0 92.5 30.7 0.1 0.6 31,2 0.2 1.4 31,4 0.8 0.1 31,2 0.3 1,2 96 30.3 0.3 1,0 31.8 0.3 0.1 31.8 0.3 0.1 31,4 0.5 0.5 TU 301-06-26-90 > 27 <1.5 <2.0 > 27 <1.5 <2.0 > 27 <1.5 <2.0 > 27 <1.5 <2.0 Average 30.3 0.5 0.8 31.7 0.2 0.5 31.6 0.6 0.4 31,4 0.7 0.5 SiO _{2 is} absent in all samples

Claims (5)

1. The method of producing sodium hydrosulfide, including the interaction of sodium hydroxide with hydrogen sulfide, characterized in that pre-receive hydrogen sulfide and barium sulfate by decomposition of barium sulfide by treating the barium sulfide pulp with sulfuric acid at a molar ratio of BaS to H ₂ SO ₄ equal to 1.0: 1 , 0-1.2, the obtained barium sulfate is separated from the liquid phase by filtration, then barium sulfate is subjected to reduction calcination at a temperature of 900-1200 ° С to obtain a barium sulfide melt, which is leached with water to obtain su pulp fida barium, resulting in the leaching stage, the pulp is recycled to the barium sulfide with sulfuric acid processing. 2. The method according to claim 1, characterized in that the concentration of pulp of barium sulfide used for treatment with sulfuric acid is 15-25 wt.%. 3. The method according to claim 1, characterized in that coal, coke or petroleum coke are used as a reducing agent during firing. 4. The method according to claim 1, characterized in that one of the following gases is used as a reducing agent during firing: carbon monoxide (II), hydrogen, natural gas. 5. The method according to claim 1, characterized in that the barium sulfide pulp is clarified before decomposition.