(中南大學(xué) 資源加工與生物工程學(xué)院，長沙 410083)
摘 要: 以寧夏某低品位硫化銅礦為研究對(duì)象，利用嗜酸氧化亞鐵硫桿菌(Acidithiobacillus ferrooxidans)和嗜酸氧化硫硫桿菌(Acidithiobacillus thiooxidans)的混合菌，采用搖瓶浸出、小型柱浸和大型柱浸對(duì)礦石可浸性進(jìn)行研究；采用X射線衍射儀分析礦物及其浸渣的成分；采用掃描電鏡分析浸渣表面形貌及其表面元素的含量。結(jié)果表明：搖瓶礦漿濃度為5%，浸出55 d銅浸出率為94.38%；小型柱浸處理礦石2.10 kg，礦石粒度小于15 mm，浸出226 d銅浸出率為62.50%；大型柱浸處理礦石77.85 kg，礦石粒度小于25 mm，浸出285 d銅浸出率為50.63%。柱浸過程中，銅的浸出速率逐漸下降；浸渣中鈣含量基本不變，而元素硫的含量明顯增加，且存在新的石膏相；浸出后礦石表面元素硫、鈣、鐵的含量明顯增加，在浸出過程中生成的硫酸鈣結(jié)晶覆蓋在礦石表面，鐵在礦石表面形成沉淀，使礦石的滲透性變差，導(dǎo)致銅的浸出率逐漸下降。
關(guān)鍵字: 硫化銅礦；硫酸鈣；細(xì)菌浸出；鐵沉淀
CHANG Zi-yong, KUANG Hao-hua
（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
