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

This paper discusses a case study on a bioheapleaching system operated commercially at Zijinshan copper plant in China, which applied bioheapleaching–SX (solvent extraction)–EW (electrowinning) to treat a distinct secondary copper sulfide ores. The operating parameters and microbial community structure succession were summarized in this paper, and their correlation with the system characters is studied. Over the four years of industrial operation, fully taking advantages of high acidity, high iron concentration, high salinity and elevated temperature caused by the high content of pyrite (5.8%) within the ore, the growth of iron oxidizers was inhibited and that of sulfur oxidizers were promoted to dominate the heap. Copper was leached efficiently with a recovery of 80%, according to the residue analysis and iron was balanced at low cost by jarosite formation in the heap, using appropriate engineering technologies such as multi-lift permanent stacking in coarse particle size (P80 = 40 mm), without agglomeration and aeration. The total operation cost was low at 1.10 USD/lb at a low copper grade of 0.38%. The case study presented in this paper provides operational data and analysis that would benefit the optimization of similar bioleach plants of secondary copper sulfide.

Research Highlights
► A distinct bioheapleaching system was introduced.
► High acidity, high iron concentration, high salinity and elevated temperature were achieved.
► Microbial structure was different from other bioheapleaching system.
► Copper was leached efficiently and iron was balanced at low cost.