Bir Altın Cevherinde Başlıca İşlem Parametrelerinin Liç Verimine Etkilerinin İncelenmesi

Abstract

Cyanide leaching has been widely used in the recovery of gold for many years. In recent years, cyanide leaching has also been applied in many gold producing plants in Turkey. In tank leaching, which is one of the widely used cyanidation methods, kinetics of gold dissolution is affected by; ore particle size, mineralogy, liberation size, percent solids of the slurry, free cyanide concentration, dissolved oxygen concentration, other soluble metals, sulfide minerals, etc. In gold processing plants, in order to maintain as high gold recovery as possible, free cyanide concentration and dissolved oxygen concentration levels are kept at much higher (excess) molar ratios than the required molar balances. On the other hand, although ore mineralogy is not an adjustable parameter, particular ore blending strategies could be applied in order to minimize the issues arising from the ore variability. Therefore, in an operating plant, ore grind size and pulp solids content stand out as important process variables as they significantly affect the leaching kinetics. In this thesis, the effects of particle size distribution, pulp solids content and initial free cyanide concentration on leaching kinetics are investigated with the experimental studies carried out on samples taken from the slurry feed of the leaching circuit of a gold mine. The experimental results show that, the retention time could be increased up to 48 hours by increasing the pulp solids content from 45% to 50%, and in this case 0,5-1,0% increase in metal recovery could be obtained. In the existing grinding circuit, decreasing the grind size of leach feed from 66 μm to 37 μm will provide 1,12% increase in metal recovery.