Flotation separation of fine smithsonite from calcite using sodium hexametaphosphate as the depressant in the Na2S-Pb(Ⅱ)-KIAX system

作者：Liao Runpeng; Wen Shuming; Liu Jian; Feng Qicheng

来源：Separation and Purification Technology, 2022, 295: 121245.

DOI：10.1016/J.SEPPUR.2022.121245

• Sulfidized smithsonite and calcite
• Pb(Ⅱ) species adsorption
• Sodium hexametaphosphate
• Flotation separation

In this study, the effects of sodium hexametaphosphate (SHMP) on the flotation of fine smithsonite and calcite in the Na2S-Pb(Ⅱ)-KIAX system were investigated. The micro-flotation results demonstrated that the fine smithsonite and calcite exhibited similar floatability in the Na2S-Pb(Ⅱ)-KIAX flotation system. After adding 20?mg/L SHMP, the flotation recovery of calcite was reduced by 43.52%, while smithsonite was hardly affected. Furthermore, the mechanism of the selective separation was systemically investigated via ultraviolet–visible spectroscopy analysis, zeta potential measurements, Fourier transform infrared spectroscopy (FTIR) analysis, and X-ray photoelectron spectroscopy (XPS) analysis. These results demonstrate that SHMP played a dual role in the flotation process. The SHMP acted as a depressant by promoting the formation of CaHPO4 and Ca(H2PO4)2 on the calcite surfaces. In addition, it acted as a dispersant and significantly decreased the mineral zeta potential to improve the repulsive force betwee...