Bioleaching of copper from pre and post thermally activated low grade chalcopyrite contained ball mill spillage

• Published in: Frontiers of environmental science & engineering 2013-04, Vol.7 (2), p.281-293
• Main Authors: Panda, Sandeep, Pradhan, Nilotpala, Mohapatra, Umaballav, Panda, Sandeep K, Rath, Swagat S, Rao, Danda S, Nayak, Bansi D, Sukla, Lala B, Mishra, Barada K
• Format: Article
• Language: English
• Subjects: Acidithiobacillus ferrooxidans; Bacterial leaching; ball mill spillage; bioleaching; Cell culture; Chalcopyrite; Copper; Earth and Environmental Science; energy; Environment; Field emission microscopy; Flasks; fluorescence; Inoculum; Leaching; Mineralogy; Mixed culture; particle size; Process parameters; pulp; Pyrite; pyrites; Recovery; Research Article; Rocks; Scanning electron microscopy; Silicon dioxide; Spectroscopy; Spillage; temperature; thermal activation; X-radiation; X-ray fluorescence; 低品位铜矿; 前处理; 场发射扫描电子显微镜; 溢出物; 热激活; 球磨机; 生物浸出; 花岗岩类岩石
• ISSN: 2095-2201; 2095-221X
• DOI: 10.1007/s11783-013-0484-5

Bioleaching of a low grade chalcopyrite （ball mill spillage material） was tested for copper recovery in shake flasks. The original samples （as received） were thermally activated （600℃, 30 min） to notice the change in physico-chemical and mineralogical characteristics of the host rock and subsequently its effect on copper recovery. A mixed culture of acidophilic chemolithotrophic bacterial consortium predominantly entailing Acidithiobacillus fer- rooxidans strain was used for bioleaching studies and optimization of process parameters of both original and thermally activated samples. Mineralogical characteriza- tion studies indicated the presence of chalcopyrite, pyrite in the silicate matrix of the granitic rock. Field emission scanning electron microscopy coupled with Energy dispersive spectroscopy （FESEM-EDS） and X-ray Fluor- escence （XRF） analysis indicated mostly SiO2. With pH 2, pulp density 10% w/v, inoculum 10% v/v, temperature 30~C, 150 r.min-~, 49% copper could be recovered in 30 days from the finest particle size （- 1 ~ 0.75 mm） of the original spillage sample. Under similar conditions 95% copper could be recovered from the thermally activated sample with the same size fraction in 10 days. The study revealed that thermal activation leads to volume expansion in the rock with the development of cracks, micro and macro pores on its surface, thereby enabling bacterial solution to penetrate more easily into the body, facilitating enhanced copper dissolution.