THERMODYNAMIC ANALYSIS OF Mn, As-CONTAINING SYSTEMS BASED ON E-pH DIAGRAMS AND PARTIAL PRESSURES

The disposal of arsenic and the use of waste containing it remains an acute problem today. The withdrawal of arsenic in various forms from the production turnover of metallurgical enterprises does not solve the environmental problem, the territories adjacent to the enterprises are subjected to gradual pollution and poisoning with arsenic-containing compounds, as a result of their gradual dissolution and accumulation in soil and groundwater.Researches of scientists have shown the effectiveness of the use of manganese compounds for the removal of arsenic from sulfuric acid solutions of copper production. Since manganese and its compounds are relatively valuable raw materials, the burial of manganese-, arsenic-containing wastes seems to be inexpedient. In the article, for the first time, a thermodynamic analysis of the behavior of arsenic and manganese was carried out on the basis of potential-pH diagrams and partial pressures. The course of chemical reactions in manganese and arsenic-containing systems, the directions of reactions and the stability of their constituent phases, the thermodynamics of the possible behavior of the participating components, their compounds, their stability regions, and the chemical nature of the products of oxidation and reduction have been studied. The areas of existence of manganese arsenate are determined, chemical and electrode reactions of obtaining manganese arsenate from manganese and arsenic compounds are considered. The results of the work confirm the possibility of using manganese compounds to remove arsenic from solutions in the form of slightly soluble manganese arsenate, which can be isolated as a product.