İnce Öğütmenin Karıştırmalı Tank Liçi Atığından Altın Geri Kazanımı Üzerindeki Etkilerinin Araştırılması

Abstract

Today, it is seen that fine grinding applications are becoming increasingly common in the mining industry due to the decreasing ore grades and the finely disseminated mineral grains in the ore, and the grinding size is gradually reduced. In addition, ultrafine grinding techniques have been used as an alternative for the economy of the gold process in order to increase the dissolution kinetics by increasing the surface area of the ore or to expose the gold particles in ultra fine size inclusions and bring them into contact with cyanide.

Within the scope of this thesis, the change in Au recovery after cyanide leaching was observed for a gold mine tailing ground in different particle sizes. Under the current plant conditions, gold is recovered at an average of 87% from the ore which is ground to P80~75 microns and the tailing is sent to the tailings dam after detox unit. The tailing taken from the detox unit was ground in a stirred mill in order to achieve P80=38 µm, 31 µm, 21 µm, 13 µm and 6 µm, and cyanide leaching tests were carried out for different time intervals. In order to observe the difference in the leaching kinetics of the tailing, cyanide leaching tests with similar particle sizes were also carried out on high and low Au grade run-of-mine ores obtained from the same gold mine.

During the bottle roll tests carried out at laboratory scale, Au recoveries were calculated for 2, 4, 8, 24, 48 hours, and chemical consumptions were also recorded. When the results were evaluated, it was observed that the Au recovery, which was 12,1% at the end of the 24-hour leaching period for 75 µm size, increased to 85,4% at 6 µm size, and this value reached up to 91% at the end of 48 hours. Compared to the high and low grade ROM ore, the rate of increase in the Au recovery of the tailing was relatively higher depending on the grind size.

According to the laboratory scale tests, it was observed that fine grinding of tailing increases total Au recovery up to 98%, roughly from current 87% Au recovery in the plant. However, there is no cost analysis conducted during the study. Therefore, feasibility analysis of the additional grinding and leaching circuit should also be considered.