Hydrometallurgical processing of non-concentrated manganese - containing raw material with receiving high-quality products

Abstract

The production of ferroalloys occupies a leading position in the economy of the Republic of Kazakhstan. With the depletion of rich in the content of the initial manganese raw materials, a problem arose that it was necessary to involve technogenic products, i.e. poor sub-standard ores and wastes produced by ferroalloys. From the point of view of environmental protection of regions producing manganese alloys, the current tasks are: the introduction of new efficient dust collection processes; issues of cleaning of waste gases and sludges; neutralization and utilization of waste. The creation of rational technological schemes for the utilization of dispersed materials that contain the target element of the ferroalloy to be melted is an economically viable and environmentally sound measure for increasing the profitability of production. Sulfuric acid leaching is the main operation of most schemes of hydrometallurgical processing of manganese-containing raw materials. Hydrogen peroxide, metallic iron, pyrite concentrate, sulfur dioxide, sulfite-bisulphite solutions used as the reducing agent. The article presents the results of hydrometallurgical processing of manganese dusts produced by the silicomanganese of the Aksu Ferroalloy Plant. To convert the solution of psilomelane (MnOMnO2) – an oxide compound, in which manganese is represented in silicomanganese dust, the presence of a reducing agent in the sulfuric acid solution, which is used as a pyrite concentrate, is necessary. The effect of pyrite on the reduction of manganese dioxide during leaching with sulfuric acid studied by mathematical planning of the experiment by a probabilistic-deterministic method. The determining factors of the leaching process are: temperature, duration of the process, amount of pyrite added, concentration of sulfuric acid. On the basis of significant equations of partial dependence, a mathematical model for the leaching of manganese dust by sulfuric acid in the presence of pyrite is compiled in the form of a generalized equation: Yрасч = 3,7•10-6(0,9399х1+5,1847)(-13,761х22+62,507х2+23,402)(-0,7429х32+14,143х3+23,4)(-00071х42+1,466х4+18,323). On the basis of the obtained equation, the optimal conditions for manganese leaching into a sulfuric acid solution are selected: temperature 700 °C, duration 3 hours, sulfuric acid concentration 5 %, additive of pyritic concentrate 90 % of the dust weight. The degree of manganese extraction was 95.8 %.