ОПРЕДЕЛЕНИЕ ЦЕЛЕСООБРАЗНОСТИ ГРАВИТАЦИОННОГО ОБОГАЩЕНИЯ РУДЫ МЕСТОРОЖДЕНИЯ «ДЖАМГЫР»

Abstract

PURPOSE. The paper studies the material composition of the ore from the Jamgyr deposit located in the Chatkal region of the Jalal-Abad district of the Kyrgyz Republic and determines the expediency of its gravity concentration. The ore belongs to the quartz low sulfide type. Its main valuable component is gold, the content of which averages 8.5 g/t. METHODS. Complex mineralogical analysis was performed using X-ray phase, optical and microscopic analyzes. Sulphide minerals and gold were studied using the method of selective dissolution of natural minerals. X-ray phase analysis was carried out on a portable X-ray diffractometer D2 PHASER (CuKa) of Bruker AXS design in the range of 20 angles from 5 to 80°. The obtained diffractograms were processed in the DIFFRAC.EVA program. A qualitative X-ray phase analysis was performed via comparison of standards (ICDD PDF-2) and diffractograms. A semiquantitative analysis of the sample was carried out using the DIFFRAC.TOPAS program according to Rietveld method. The content of gold was determined on the atomic absorption multielement spectrometer AGEP-0,1 by the assay atomic absorption analysis. RESULTS AND THEIR DISCUSSION. Having studied the morphology of particles of free gold, we have found that the shape of coarse gold is mainly dendritic, small-size gold has the shape of a drop in pyrite. The data on the granulometric distribution of gold show that the percentage of coarse gold is about 70%. The phase analysis data show that the percentage of free gold is 64.37%. The ore study has allowed to substantiate the use of gravity concentration through the GRG test at a hydraulic pressure of 25-12 kPa, ore feed rates from 1000 g/min to 400 g/min, stage-by-stage reduction in size from 100% of 85 μm to 80% of 75 μm. The technique of performing the stage-by-stage gravity concentration conducted in three stages on Knelson concentrator is given and the GRG test determination diagram is presented. The results of each stage and the total result of the GRG test are provided. According to the GRG test result 19.86% of free gold is extracted at the first stage, 35.83% - at the second stage, and 17.65% - at the third stage. The total recovery is 73.34%. CONCLUSIONS. The morphology and release of gold on the concentrates obtained by gravitation on a centrifugal separator are studied. The degree of gold release is determined as well as the gold grain size in I, II, III stage concentrates and relative amounts of free gold grains. The final determination is given to the main shape of gold grains: it is either dendritic or flake. It is also noted that stage-by-stage decrease in the grind size causes changes in the gold grain shape: the particles of isometric forms are expanded into flat grains.