Thermodynamic Description of Oxidized Zinc Minerals and Comparative Analysis of Their Reactivity

Abstract

Due to depletion of sulfide zinc ores, the problem of involvement of economically significant oxidized zinc ores into the treatment is a vital task. In this article, the thermodynamic functions have been considered and determined for many oxidized zinc minerals, such as calamine, smithsonite, willemite, hydrozincite and others. The reactivity of minerals was determined by the groups of the same type, and the series were compiled according to the increase in their reactivity. The Gibbs energies ?? ?? ?? ?? ?? of the chemical reaction of sphalerite (ZnS), smithsonite (ZnCO3) and calamine Zn4(Si2O7)(OH)2·H2O with sulfuric acid were calculated and the following data were obtained per 1 mol of H2SO4: for sphalerite (13.27 kJ/mol), for smithsonite (75.46 kJ/mol) and for calamine (154.07 kJ/mol). Based on the calculated thermodynamic analysis of the dissolution of these minerals, the following series of changes in the standard values of Gibbs energies ?? ?? ?? ?? ?? was established: ZnS > ZnCO3 > Zn4(Si2O7)(OH)2·H2O. The results of thermodynamic calculations make it possible to distinguish the most reactive oxidized zinc minerals, so that in future, when treating oxidized zinc ores, to know about the properties and characteristics of these minerals.