细粒铜尾矿生物柱浸体系下细菌群落对潜在的铺矿形式的响应

Responses of bacterial community to potential heap construction methods of fine-grained copper tailings in column bioleaching system

比较研究分层铺筑(LM)、聚团铺筑(AM)和烧结球团铺筑(PM)三种铺矿形式对铜浮选尾矿生物柱浸的影响。解析尾矿浸出后期三组浸矿体系下游离、吸附、弱吸附和强吸附微生物的群落结构。在AM浸出组,用于尾矿聚团的块状硫化矿的添加使浸出溶液pH值降低,三价铁离子浓度升高和微生物快速吸附。相比于LM(54.6%)和PM(43.9%)浸出组,AM浸出组得到最高的铜浸出效率(60.1%)。在不同尾矿铺筑形式下,不同微生物群的优势属的相对丰度和群落结构均发生明显变化。尾矿铺筑形式改变吸附、弱吸附和强吸附微生物群落的α-多样性指数,但未改变游离微生物群落的α-多样性。溶液pH值、总铁和三价铁浓度与整体细菌群落的变化呈现显著相关性。皮尔逊相关分析和偏最小二乘路径模型均表明吸附微生物对尾矿中铜浸出的贡献更大。

The column bioleaching of copper flotation tailings was comparatively investigated using layered heap construction method(LM),agglomerate heap construction method(AM),and pellets-sintering heap construction method(PM).The bacterial communities of free,attached,weakly-attached,and strongly-attached microbes in the later bioleaching stage were investigated.In AM group,the addition of lump sulphide ore resulted in the low leachate pH,high ferric iron concentration,and rapid microbial adsorption,which obtained the maximum copper extraction(60.1%)compared with LM(54.6%)and PM(43.9%)groups.The relative abundance of dominant genera and microbial communities of different microbiota underwent changes in three heap construction methods.The alpha-diversity indexes of attached,weakly-attached,and strongly-attached microbes were different,while no significant change was observed in free bacteria.The variation of whole bacterial community was significantly associated with solution pH,total iron,and ferric iron concentrations.Pearson correlation analysis and partial least square path model both indicated that attached bacteria made larger contribution to the copper extraction of tailings.