The Bioleaching Of Hami Low-grade Nickel-bearing Sulfide Ore

Hami Deposit is located in the Chinese Tianshan and Altay orogenic belts, Hami, Xinjiang Province, NW China. Indicated Mineral Resources of its reserve are estimated at12million tonnes averaging0.40%nickel. Mineralogical examination and chemical analysis indicated that the Yellow Mountain ore is a type of high Fe, low Mg and low Ni sulfide ore and it is necessary to develop an economical process to deal with it.In this paper, a mixed mesophiles included A. ferrooxidans, A. thiooxidans and L. ferrooxidans was used to carry out a bioleaching study on the Hami Ni sulfide poor ore and the coclusions are as follows:(1) olivine and pyroxene are the main gangue minerals in the Hami ore; pentlandite, pyrrhotite and chalcopyrite are the main sulfide minerals in the ore, the content of pyrrhotite is high to8%.(2) When iron concentration is higher than regulation of bacteria, the bacteria will die out. Through serial sub-culturing and gradually increasing dissolved iron concentration in the medium, tolerance of bacteria to dissolved iron can be increased. After52weeks’adaptation, the mixed bacteria are eugenic under0.54mol/L (30g/L) dissolved iron, reproduce very slowly under0.63mol/L (35g/L) dissolved iron and die out at a concentration of dissolved iron0.71mol/L (40g/L).(3) Using A. ferrooxidans, pentlandite was mainly leached by contacting way while pyrrhotite was mainly leached indirectly when the leaching system is at the ambient temperature and the pH value is2.0. With the increasing of the temperature and the acidity, the proportion of indirect leaching will gradually increase.(4) A recovery of93%Ni,85%Co and29.5%Cu was gotten through a40-week column bioleaching of the Hami nickel sulfide ore using mixed bacteria at the ambient temperature. The negative impact of pyrrhotite on the baterial leaching stage can be reduced effectively by using iron ion-adapted bacteria and lowing iron ion in leaching solution.