萤石-白钨矿浮选分离体系中硅酸钠的溶液化学行为

Solution chemistry behavior of sodium silicate in flotation of fluorite and scheelite

针对传统溶液化学计算法难以处理复杂溶液体系的问题,采用Newton-Raphson数值计算法对复杂溶液体系进行溶液化学计算,利用硅酸钠添加总浓度代替活度绘制新型组分浓度图,研究硅酸钠在萤石白钨矿浮选分离中的作用机理。通过进行纯矿物浮选实验、Zeta电位测试,结合组分浓度图,初步确定硅酸钠在油酸钠浮选分离萤石白钨矿中的主要抑制机理是在萤石表面选择性地生成了硅酸钙沉淀,相关的XPS分析结果进一步证实了这一结论。结果表明,在适量硅酸钠抑制条件下可以选择性地分离萤石和白钨矿,该溶液化学新方法在分析和预测盐类矿物浮选过程中具有很好的实践指导意义。

Complex solution system can be difficult to deal with by conventional solution chemistry calculation. In order to avoid this problem and investigate the influence of sodium silicate on the flotation of scheelite from fluorite, Newton-Raphson method was applied to solution chemistry calculation. And a new kind of species distribution diagram was drawn in terms of changing the total concentration of sodium silicate rather than the activity of silicate or hydrogen ion. According to the study of single-mineral flotation tests, electrokinetic measurements and species distribution diagrams, the selective surface precipitation of calcium silicate on the fluorite was identified to be the major depression mechanism of fluorite in the flotation of separating scheelite from fluorite using sodium silicate as the modifier and sodium oleate as the collector. X-ray photoelectron spectroscopic （XPS） analyses also provided strong evidence for this conclusion. The results show that the selective depression of scheelite flotation from fluorite can be achieved under conditions of moderate depression. The evaluated surface precipitation concentrations are in good agreement with the results of flotation experiments and XPS analysis results. This study also confirms that solution chemistry calculation with Newton-Raphson method has practical value in the interpretation and prediction of mineral flotation.