Industrial practice of a distinct bioleaching system operated at low pH, high ferric concentration, elevated temperature and low redox potential for secondary copper sulfide

Study of the kinetics of pyrite oxidation under controlled redox potential

“…Pyrite used for these experiments was sorted from Zijinshan. The content of the alunite in Zijinshan copper ore is about 11.67% (Ruan et al, 2011) which confirms that the above conclusion is correct. The peaks of alunite were not observed in the spectrum of the initial pyrite sample, which could be due to the low content of the alunite in the initial pyrite sample being below the detection limit for laboratory powder XRD.…”

“…Keeping the heaps of sulfide ore at high temperature is not difficult with careful operation, such as a low rate of irrigation and high lift of the heap. Many practices have demonstrated that temperatures inside heaps reached as high as 60°C, which was favorable for pyrite oxidation, including Zijinshan copper sulfide heap bioleaching (Ruan et al, 2011), Nifty copper sulfide heap bioleaching (Readett et al, 2003), Gold Quarry heap bio-oxidation (Logan et al, 2007), and Talvivaara nickel sulfide heap bioleaching (Riekkola-Vanhanen, 2007). The ferric leaching kinetics of pyrite under controlled potential suggest that ferrous biooxidation isolated from heaps under optimal conditions combined with heap leaching at high temperature might significantly accelerate the pyrite oxidation of refractory gold ores.…”

“…Microorganisms can rapidly oxidize ferrous ion to maintain the potential of the solution constant under appropriate conditions. For example, Eh of the leachate in the Zijinshan (China) bioheap is constant within the range of 710 mV to 740 mV (Ruan et al, 2011). According to typical heap bioleaching conditions, figuring out the effect of temperature on the kinetics of pyrite oxidation under the condition of constant potential is essential to improve the rate of pyrite heap bioleaching.…”

Copper Bioleaching in China: Review and Prospect

“…Due to lower recovery and high cost of traditional mining methods, the ZCM has been extracting copper using bioheap leaching since the 1998. A Solvent Extraction/Electro-Winning (SX-EW) commercial bioleaching plant, designed by China ENFI Engineering Corporation was constructed in 2000 and has been operational since the 2005 with a capacity of 20,000 t/a at a copper extraction rate of 80% [87][88][89]. The bacteria are mixture strains of Acidithiobacillus (>51%), Leptospirillum (>48%), and Ferrimicrobium (~1%) obtained from AMD, Zijinshan Copper Mine [90,91].…”

Synchronous recovery of iron and electricity using a single chamber air-cathode microbial fuel cell

“…The (bio)leachate and mining/metallurgical streams were main contributor of heavy metals to water body environment. To remove metals from those streams, the methods generally involved in membrane separation, 4 electrowinning, 5 absorption, 6 biological transform etc. 7 On the other side, those streams also provided options for valuable metal recovery, which possibly made removal processes more economical and sustainable.…”