DETERMINATION OF SUBSTANTIAL COMPOSITION OF GOLD-BEARING RAW MATERIAL AND DEVELOPMENT OF TECHNOLOGY FOR ITS PROCESSING

摘要

The studies to determine material composition of ore and develop the procedure for processing of oxidized ore from the western flank of Karyernoye deposit with complex mineral and phase composition and low gold content were conducted. Urgency of these studies is determined by difficulty of this type of crude ore processing, wherein basic metal - gold is scattered throughout various phases, its content is low, and its recovery is very complicated at processing the same raw materials at plants. The representative technological sample (TS-3) of initial ore, related to the oxidized type due to low content of sulfide sulfur, was taken. Based on substantial composition, it represents hydrothermally altered sandstone, silty sandstone and siltstone with veinlets of quartz or carbonate-quartz composition, and is characterized by gold-sulfide-quartz formation of the impregnated type. Phase and elemental compositions, forms of gold existence and nature of its bond with ore constituents were examined by chemical, X-ray phase, X-ray fluorescence, rational, and assay methods of analysis. Ore mineralization is pyrite, gold content in the sample is 0.44 g/t. Basic mineral constituents are quartz (45.0 %) and albite (3.5 %), whereas pyrite content is 1.4 %. According to the results of the rational analysis, gold is found in all four phases and mainly (72.4 %) presented in rock-forming minerals in the form of fine-grained gold, significant amount of gold (24.1 %)- in the form associated with crystal lattices of mineral carrier, and small amounts of gold occur in the form of native and quartz-covered. Three-stage ore gravity benefication was carried out, and maximum gold recovery to concentrate was 47.2%. Closed-cycle flotation benefication (3 times re-cleaning) allows recovery 64.7 % of gold into concentrate. Direct cyanide leaching of initial ore milled to -0.071 mm grain size class (80 % and 90 %) allowed converting from 86.3 % up to 90.9 % of gold into solution.