Gold Extraction from Cyanidation Tailing Using Microwave Chlorination Roasting Method

Abstract

At present, gold mines are increasingly scarce in the world. The yield of cyanidation tailing (CT) of refractory gold ores with a grade of 10 g/T is huge; however, the effective capitalization of the cyanidation tailing is a significant problem in the gold industry. In this work, a new treatment method, a microwave-roasting process developed. The effect of roasting temperature, calcium chloride concentration, holding time and mineral size on the recovery of Au researched under conventional and microwave conditions. It found that, under the same processing conditions, the Au recovery in the microwave field is much higher than that of conventional conditions. The preliminary reinforcing role of the microwave discussed in the recovery of gold. This might be because of the microwave absorption ability of CaCl2 is much better, heated quickly and the reactions intensified among CaCl2, O2, and H2O. As a result, the extraction of gold in CT drastically increased in the microwave field, and the microwave roasting technology shows the characteristics of environmental protection in terms of low energy consumption and high efficiency.

Effect of Power and Exposure Time on the Microwave-Assisted Roasting of Refractory Gold Ore

“…Experimental. Gold ore from the mine site is dried and ground to a size <75 µm [15], [18], [20], [21]. Furthermore, sampling was carried out by a rotary sample divider.…”

Recovery of Metals and Rare Earth Elements by Microwave heating Technology - A Review

“…The results show that the highest recovery of Au can reach 97%, and it is found that the recovery of Au concentrate increases rapidly with the extension of microwave heating time. Zhu et al (Zhu et al, 2018) used microwave refractory Au cyanide tailings (CT) to achieve low energy consumption and high efficiency to recover Au from Au CT. They also found that substances with stronger microwave absorption capacity such as CaCl2 can aggravate the reaction, which shown that substances with strong microwave absorption capacity can speed up the reaction process and reduce the reaction time.…”