Pretreatment of deep-sea bacteria for reverse flotation of magnesite tailings: Cleaner production, behavior and mechanism

Abstract

According to the principle of cleaner production, strengthening the selectivity and separation effect of dodecylamine (DDA) as a conventional reverse flotation agent is an effective way to realize the re-enrichment of magnesite tailings, reduce the cost of agents, recover valuable elements, improve the quality of products and industrialize high value-added utilization. In this study, we designed the technology of microbial pretreatment-reverse flotation of magnesite tailings, and used the deep-sea silicate bacteria SiBY-2 to pretreat magnesite tailings, which enhanced the separation efficiency of magnesite from silicon bearing gangues in the reverse flotation process. The results show that the SiBY-2 enhances the desilication effect of magnesite tailings mainly by secreting organic acids, polysaccharides and proteins, and intensifies the interaction between silicon bearing gangues and the collectors (DDA). Compared with the conventional reverse flotation, the concentrate grade and recovery of the SiBY-2 pretreatment-reverse flotation process is increased by 2.04% and 5.93% respectively, while the utilization rate of DDA is reduced by 9.0%. It is estimated that the production cost of magnesite can be reduced by 900–1350 ¥/t, which achieves the purpose of clean production of magnesite high quality products.