难免离子对中低品位钙镁质磷矿石反浮选的影响

摘要

采用浮选试验,结合溶液化学计算、方差分析、扫描电镜和X射线荧光光谱分析等手段研究难免离子对中低品位钙镁质磷矿石反浮选的影响.研究结果表明:矿浆中Ca2+和Mg2+会降低浮选磷精矿中P2O5含量而提高MgO含量,原因是Ca2+和Mg2+会沉淀捕收剂解离的RCOO-,降低其有效浓度;SO42-会降低磷精矿中P2O5回收率,其作用机理是由于SO42-能与Ca2+作用生成硫酸钙沉淀并覆盖在氟磷灰石和白云石表面,增强氟磷灰石的可浮性,导致氟磷灰石随白云石一起浮出;PO43-对浮选影响较小;Ca2+、Mg2+、SO42-和PO43-对磷精矿中SiO2、Al2O3和Fe2O3含量影响较小.由于Ca2+和SO42-分别对磷精矿P2O5品位和P2O5回收率影响显著,因此在回水利用过程中需控制矿浆中Ca2+和SO42-浓度,降低其对浮选的影响.%Effects of unavoidable ions on flotation of mid-low grade calcareous-magnesium phosphate ore were investigated by flotation test,solution chemistry calculation,variance analysis,scanning electron microscopy and X-ray fluorescence analysis. The results showed that the calcium and magnesium ions in the ore pulp decreaseed the P2O5 content and increaseed MgO content because these ions precipitated the RCOO- from the dissociation of capture agents,reducing their effective concentration. Sulfate ions decreased the recovery of P2O5 in phosphorus concentrate. The mechanism is that sulfate ions can react with calcium ions and produce calcium sulfate precipitation,which coat the surfaces of fluorapatite and dolomite to enhance the floatability of fluorapatite,leading to fluorapatite float together with dolomite. Phosphate ions had ignorable influence on flotation,and all these above ions had little influence on SiO2,Fe2O3 and Al2O3 content. Due to the significant influence of calcium and sulfate ions on the P2O5 grade and recovery in phosphorus concentrate,the concentration of calcium and sulfate ions in the ore pulp should be controlled in the process of recycling water utilization to reduce its effect on flotation.