Carbon-Assisted Bioleaching of Chalcopyrite and Three Chalcopyrite/Enargite-Bearing Complex Concentrates

Minerals

Kyohei Takamatsu¹  Kaito Hayashi¹  Keishi Oyama¹  Naoko Okibe¹  Shigeto Kuroiwa²  Yuji Aoki²  Tsuyoshi Hirajima² 

[1] Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan;Sumitomo Metal Mining, Co. Ltd., Ehime 792-0002, Japan;

关键词: bioleaching;    carbon;    chalcopyrite;    enargite;    solution redox potential (E_h);    normalized redox potential (E_normal);   

DOI  :  10.3390/min11040432

来源: DOAJ

【 摘 要 】

Overcoming the slow-leaching kinetics of refractory primary copper sulfides is crucial to secure future copper sources. Here, the effect of carbon was investigated as a catalyst for a bioleaching reaction. First, the mechanism of carbon-assisted bioleaching was elucidated using the model chalcopyrite mineral, under specified low-redox potentials, by considering the concept of E_normal. The carbon catalyst effectively controlled the E_h level in bioleaching liquors, which would otherwise exceed its optimal range (0 ≤ E_normal ≤ 1) due to active regeneration of Fe³⁺ by microbes. Additionally, E_normal of ~0.3 was shown to maximize the carbon-assisted bioleaching of the model chalcopyrite mineral. Secondly, carbon-assisted bioleaching was tested for three types of chalcopyrite/enargite-bearing complex concentrates. A trend was found that the optimal E_h level for a maximum Cu solubilization increases in response to the decreasing chalcopyrite/enargite ratio in the concentrate: When chalcopyrite dominates over enargite, the optimal E_h was found to satisfy 0 ≤ E_normal ≤ 1. As enargite becomes more abundant than chalcopyrite, the optimal E_h for the greatest Cu dissolution was shifted to higher values. Overall, modifying the E_h level by adjusting AC doses to maximize Cu solubilization from the concentrate of complex mineralogy was shown to be useful.

【 授权许可】

Unknown