Extraction of gold from low-sulfide gold-bearing ores by beneficiating method using a pressure generator for pulp microaeration

Abstract

Research results on the study of the material composition of low-sulfide gold-bearing ore from the East Kazakhstan deposit are presented. The main non-metallic minerals of the original sample and beneficiation products include quartz, chlorite (clinochlore), carbonates (calcite and dolomite). Pyrite is present predominantly in the form of cubic crystals, sometimes in the form of clusters. The grain size is from 0.03 to 0.40.5 mm, the size of the clusters reaches several mm. Iron oxides (goethite, hydrogoethite) were formed on pyrite, possibly magnetite and ilmenite. The assay test found that the test sample contains 6.04 g/t Au and 7.9 g/t Ag. The content of sulfide minerals is 11.81%. A significant part of gold (85.51%) is in a finely disseminated state in sulfides, as well as in rock-forming minerals 1.22%. The paper presents the results of laboratory studies of the gold- ore beneficiation ability using gravity concentration processes. Gravity enrichment tests were performed on laboratory equipment: Knelson KS-MD 3 centrifugal concentrator, SKO-05 concentration table, and a two-chamber diaphragm jig (OML TsNIGRI type (jig of Central Geological Research Institute for Nonferrous and Precious Metals)). The obtained results of ore beneficiation on the concentration table show the possibility of obtaining a gravity concentrate with a gold grade of 48.9 g/t with a gold recovery of 40.08%. When separating the gravity concentrate on a jig, the gold extraction was 31.6% at a content of 51.4 g/t. It was found that that according to a single-stage beneficiation scheme in a centrifugal concentrator, a gold-bearing concentrate with a gold content of 58.3 g/t was obtained with a recovery of 80.6%. The dependence of the gold extraction and its content in the gravity concentrate on the output at the Knelson centrifugal concentrator is shown. The results of ore flotation beneficiation show the possibility of obtaining waste grade flotation tailings with a gold grade of 0.8 g/t. The extraction of gold into the combined concentrate, with a gold content of 49.7 g/t, is 88.88%.