The Effects of Milling and pH on Co, Ni, Zn and Cu Bioleaching from Polymetallic Sulfide Concentrate

Acid bioleaching of a low-grade and polymetallic sulfide concentrate was studied, in order to determine suitable feed material particle size pH for efficient leaching valuable metals. The consisted pyrite (50 wt %), pyrrhotite (31 quartz (10 %) lower amounts cobalt, nickel, zinc copper (each <1 %). After adaptation microorganisms shake flasks, stirred tank tests were conducted at different levels supplementing sizes (milled d80 < 150 µm, <50 <28 <19 µm). operation 1.8 seen prone iron precipitation, while this not observed between 1.3 1.5. Additional milling decrease from the initial µm had major positive effect on cobalt- nickel-leaching yields, proposing that least 28 should be targeted. best yields main economic elements, cobalt 98% 94%, respectively, reached with 19 1.3. However, it considered 1.5, similar results could obtained. This research sets basis continuing experiments continuous pilot scale.