黄铁矿促进黄铜矿微生物浸出影响因素

Influence factors of pyrite promotion on the bioleaching of chalcopyrite

采用摇瓶实验,以氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,At.f)浸出黄铁矿--黄铜矿,重点研究了基础培养基、矿物配比和粒度组成等因素的影响.黄铁矿能促进黄铜矿的微生物浸出,以采用无Fe 9K培养基效果较好,它对应铜浸出率是9K培养基的1.68倍;采用宽粒级矿物时铜浸出效果较好,且铜浸出率与黄铁矿和黄铜矿的质量比有关,当质量比为2∶2时铜浸出率最高可达45.58%;黄铁矿含量大小是影响铜浸出率高低的实质,当质量比小于等于5∶2时以At.f菌的氧化作用为主,当质量比为10∶2时以硫化矿间的原电池效应为主.浸渣的X射线衍射分析表明,采用无Fe 9K培养基时浸渣中生成的钝化物黄钾铁矾较少,故黄铁矿可以很好地替代9K培养基中的FeSO4,并能与黄铜矿形成原电池效应,从而促进铜的浸出.

Chalcopyrite-pyrite bioleaching tests were performed with shaking flasks by Aeidithiobacillusferrooxidans. The research focused on the effects of basic salt mediums, pyrite-to-chalcopyrite mass ratio and mineral size distribution. It is found that chaleopyrite bioleaching can be promoted by pyrite, The leaching rate of copper in the iron-free 9K medium in pyrite-chaleopyrite bioleaching is 1.68 times as large as that in the 9K medium. The leaching of copper is better using a wide size range of minerals and the leaching rate of copper is related to the mass ratio of pyrite to chalcopyrite. When the mass ratio is 2： 2, the highest leaching rate of copper is ob- tained to be 45.58%. The content of pyrite is of the essence in affecting the leaching rate level of copper. At a mass ratio of pyrite to chalcopyrite no more than 5：2 the oxidation of Acidithiobacillus ferrooxidans plays an important role in the bioleaching, but when the mass ratio is 10：2 the galvanic effect between the two sulphide minerals mainly influences the bioleaehing. X-ray diffraction analyses of leaching residues indicate that the generation of jarosite in the iron-free 9K medium is less than that in the 9K medium, FeSO4 in the 9K medium can be replaced by pyrite, the galvanic effect forms with chaleopyrite, and therefore the bioleaehing efficiency of copper is increased.