(中南大学 资源加工与生物工程学院，长沙 410083)
摘 要: 以宁夏某低品位硫化铜矿为研究对象，利用嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)和嗜酸氧化硫硫杆菌(Acidithiobacillus thiooxidans)的混合菌，采用摇瓶浸出、小型柱浸和大型柱浸对矿石可浸性进行研究；采用X射线衍射仪分析矿物及其浸渣的成分；采用扫描电镜分析浸渣表面形貌及其表面元素的含量。结果表明：摇瓶矿浆浓度为5%，浸出55 d铜浸出率为94.38%；小型柱浸处理矿石2.10 kg，矿石粒度小于15 mm，浸出226 d铜浸出率为62.50%；大型柱浸处理矿石77.85 kg，矿石粒度小于25 mm，浸出285 d铜浸出率为50.63%。柱浸过程中，铜的浸出速率逐渐下降；浸渣中钙含量基本不变，而元素硫的含量明显增加，且存在新的石膏相；浸出后矿石表面元素硫、钙、铁的含量明显增加，在浸出过程中生成的硫酸钙结晶覆盖在矿石表面，铁在矿石表面形成沉淀，使矿石的渗透性变差，导致铜的浸出率逐渐下降。
关键字: 硫化铜矿；硫酸钙；细菌浸出；铁沉淀
（School of Resource Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract:A mixed culture consisting of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans was used to study technical feasibility of bioleaching of some copper sulfide ore from Ningxia. The bioleaching test was carried out in flask, small-scale column and large-scale column. The residues were analyzed by chemical analysis and X-ray diffractometry. The residues surface and element content were analyzed by scanning electron microscopy and energy spectrum. The results show that 94.38% copper is extracted after 55 d in flask with a pulp density of 5%. 62.50% copper is extracted after 226 d in small-scale column with 2.10 kg ore, and the ore particle size is lower than 15 mm. 43.03% copper is extracted after 285 d in large-scale column with 77.85 kg ore, and the ore particle size is less than 25 mm. The copper leaching rate decreases gradually in later process, which is related with calcium sulphate and iron precipitation. In the residues calcium content is essentially the same, but the sulfur content evidently increases and gypsum is found, calcium and iron on the surface evidently increase, calcium sulphate crystallizes and iron precipitates on the ore surface, which worsen the penetrability of the ore and result in gradually dropping of copper leaching rate.
Key words: copper sulfide; calcium sulphate; bacterial leaching; iron precipitation
