Abstract:

Owing to the substantial amounts of metals embodied in tailings, they are potential viable sources of metals. This work aims at developing a technique to microbially recover copper present in tailings. Based on orthogonal design, the effects of different variables, such as temperature, fermentation time, inoculum size and medium components, on pellet morphology of A. niger were investigated in shake flasks. Leaching of copper from its tailings was conducted using fermentation broths of Aspergillus niger with different pellet morphology. Copper extraction gradually increased with reduction in pellet diameter of A. niger. A large amount of compact smooth pellets with a diameter of 0.96 mm were obtained under the optimum fermentation conditions of 30℃, 0.8% inoculum size(OD₆₀₀=0.1), 30% potato-sucrose contents, 65 h fermentation time. After 3 days of leaching, copper extraction reached 83.25% with the fermentation broths aforementioned at 30℃, 180 r·min^-1.

Key words: Aspergillus niger, mycelium pellets, fermentation, leaching, copper mill tailings, optimization

摘要：

尾砂中含有大量的金属,是一种潜在的可利用资源。旨在研发一种从铜尾砂中回收铜的生物浸出方法。利用正交设计,通过摇瓶试验,研究培养温度、发酵时间、接种量及培养基成分对黑曲霉菌丝球形态的影响,进而研究不同菌丝球形态的黑曲霉发酵液对尾砂中铜的浸出。研究表明,铜的浸出率随着黑曲霉菌丝球直径的减小而升高。在温度30℃,接种量0.8%(OD₆₀₀=0.1),马铃薯-蔗糖含量30%,发酵时间65 h的优化发酵条件下,获得大量表面光滑、直径为0.96 mm的菌丝球;利用该条件下的发酵液,在30℃,180 r·min^-1条件下浸出3 d,铜的浸出率达83.25%。

关键词: 黑曲霉, 菌丝球, 发酵, 浸出, 铜尾砂, 优化