RU2186020C2 - Method of sulfur production - Google Patents

Abstract

FIELD: inorganic chemistry, chemical technology. SUBSTANCE: invention relates to methods of production of sulfur from solution containing sulfide, sulfite and sulfate sulfur. Method of production of sulfur from the solution containing sulfide, sulfite and sulfate sulfur also involves acidification of its alkaline solution with hydrochloric acid to pH = 3-4 and addition of SnCl₂ to the solution as a reducing agent in concentration up to 10 wt.-% of total sulfur content in the solution and additional addition of hydrogen peroxide. Invention ensures to increase the rate of reaction and carry out the production of sulfur from solutions containing both sulfate sulfur and sulfide and sulfite sulfur. EFFECT: improved method of production.

Description

 The invention relates to methods for producing sulfur from a solution containing sulfide, sulfite and sulfate sulfur.

 In particular, from aqueous solutions obtained in the processing of ores and sludges of metallurgical production containing elemental, sulfide, sulfite and sulfate sulfur.

A known method of producing elemental sulfur from an aqueous solution containing sulfites, ammonium bisulfites, alkali or alkaline earth metals, by treatment with a reducing agent at 20-150 ^o C and a pressure high enough to prevent the transition of liquid into steam. Processing is carried out in two stages. Sulfur, polysulfite compounds, water-soluble sulfides, hydrogen, carbon monoxide or a mixture thereof are used as a catalyst (US Patent 3,728,439, publ. 04/17/1973) (1).

 The closest is the method of producing elemental sulfur from an alkaline solution obtained by processing the solid residue from acid leaching of copper-bismuth concentrate after extracting selenium and tellurium from it by treating it with a reducing agent (RF patent RU 2097316 C1, publ. 11/27/1997 (2).

 The disadvantage of this method is that this method does not allow the extraction of sulfate sulfur and requires preliminary extraction of selenium and tellurium, and only copper-bismuth concentrate is used as a feedstock, and the reaction rate for the extraction of sulfide and sulfite sulfur is low.

 The aim of the invention is to obtain sulfur from a solution containing sulfate sulfur along with sulfide and sulfite sulfur without prior removal of selenium and tellurium, in addition, an increase in the reaction rate of sulfur production from its sulfide and sulfite compounds.

 This goal is achieved by the additional introduction of hydrogen peroxide in a solution containing sulfate, sulfide and sulfite sulfur. The claimed method allows to extract sulfate sulfur along with sulfite and sulfide with preliminary and without preliminary extraction of selenium and tellurium. The source of raw materials can be any sulfur-containing material from which sulfur can be extracted by the claimed method.

 The method is as follows.

When processing ores containing elemental, sulfide, sulfite, and sulfate sulfur with mineral acids (HCl, H ₂ SO ₄ , HNO ₃ ) (regardless of the initial composition of polymetallic ore), as a result of reaction with sulfur-containing products, depending on various situations, often elemental sulfur is formed, which then passes into the solid phase.

1) SO ₂ + 2H ₂ S = 3S + 2H ₂ O
2) 6HCl + H ₂ SO ₄ (at a concentration of more than 80%) = 3Cl ₂ + 4H ₂ O + S
3) HClO + H ₂ S = HCl + S + H ₂ O
4) H ₂ S + Cl ₂ = 2HCl + S
5) H ₂ S + 2HNO ₃ = S + 2NO ₂ + 2H ₂ O
Then the solid phase or material containing these types of sulfur is treated with a concentrated alkali solution at t = 150-200 ^o C.

6) 3S + 6NaOH = Na ₂ SO ₃ + 2Na ₂ S + 3H ₂ O.

As a result of the reaction, sulfur transforms into a sulfite and sulfide form. Such a solution often also contains sulfate sulfur. To obtain sulfur from all of these forms, the alkaline solution is acidified with hydrochloric acid to pH 3-4 and the SnCl ₂ reducing agent is introduced into it to 10 wt.% Of the total sulfur content in the solution.

In order to extract sulfate sulfur and at the same time increase the reaction rate of extraction of sulfite and sulfide sulfur into the solution, hydrogen peroxide is additionally introduced. The latter is clearly seen from the estimate of the equilibrium constants of reaction (7) and (8) in accordance with the law of mass action. In particular, an estimate of the ratio of the analogue reaction to the rate of the proposed reaction is of the order of Exp ⁽¹⁴⁵⁾ . The calculation of the equilibrium constants of the reaction was carried out on the basis of the thermodynamic data of the handbook (3):
7) Na ₂ SO ₃ * 2Na ₂ S + 8HCl + SnCl ₂ = 6NaCl + 3S + SnCl ₄ + 4H ₂ O.

The reaction rate of a similar method:
V '= K _p ' [Na ₂ SO ₃ * 2Na ₂ S] • [HCl] ⁸ • [SnCl ₂ ]
8) Na ₂ SO ₃ * 2Na ₂ S + 4H ₂ O ₂ + 14HCl + 4SnCl ₂ = NaCl + 3S + 4SnCl ₄ + 11H ₂ O
The reaction rate of the proposed method:
V '' = K _p '' [Na ₂ SO ₃ * 2Na ₂ S] • [H ₂ O ₂ ] ⁴ • [HCl] ¹⁴ • [SnCl ₂ ] ⁴
9) Na ₂ SO ₄ + H ₂ O ₂ + 4SnCl ₂ + 10HCl = S + 6H ₂ O + 4SnCl ₄ + 2NaCl
The described method was tested in scheelite and molybdenum concentrates.

 On the ores of the Rainbow and Karachay-Cherkess deposits, on artificial mixtures. After sulfur recovery, these types of sulfur in the solution are not detected by qualitative reactions.

Literature:
1. US patent 3728439, cl. C01 B 17/02/1973.

 2. RF patent 2097316 - prototype.

 3. Ryabin V.A. et al. Thermodynamic properties of substances. Directory. - M.: Chemistry, 1977.

Claims (1)

A method of producing sulfur from a solution containing sulfide and sulfite sulfur, by acidifying its alkaline solution with hydrochloric acid to pH 3-4 and introducing SnCl ₂ reducing agent into it to 10 wt. % of the total sulfur content in the solution, characterized in that in order to obtain sulfur from a solution containing sulfate sulfur along with sulfide and sulfite, hydrogen peroxide is additionally added to the solution.