Nitric Acid Treatment of Olympiada Deposit Refractory Gold-Bearing Concentrate

This article covers acid nitric leaching of Olympiada deposit refractory gold-bearing concentrate after alkaline leaching of stibnite. Thermodynamic analysis of the reaction pyrite and arsenopyrite with nitric acid chemical equations was performed. Equilibrium Eh-pH Pourbaix diagrams of heterogeneous systems studied, containing iron and arsenic were charted. Investigation of elemental and species analyses was maintained. The analysis of the main elements distribution and their combining over grains with the help of electron-probe microanalysis (EPMA) was investigated. It is established, that the material mainly consists of compounds of quartz, dolomite and calcite, as well as pyrite and arsenopyrite. Pre-treatment decarbonization operation of the feed material was proposed with the aim to reduce nitric acid consumption. The dependences of effects of the nitric acid concentration and L/S ratio on iron and arsenic dissolving were determined.