硫化矿浮选体系中辉银矿的浮选行为研究

摘要

The behavior of argentite during the flotation was studied,and the results showed that the floatability of argentite was much better in the weak alkaline condition(pH=9～10)than in the strong alkalinity condition(pH>11).Thermodynamic calculations revealed that the critical pH for argentite flotation was 9.38,9.11 and 11.59,respectively,when ethyl xanthate(EX)or ammonium dibutyl dithiophosphate(ADD)or diethyldithiocarbamate(DDTC)was selected as the collector.The adsorption test results indicated that the amount of these collectors adsorbed on the argentite surface reached the maximum in the weak alkaline condition,and declined sharply in the strong alkaline condition as a result of Ag2O film newly formed on the argentite surface.The film would block the adsorption process.Besides,in the weak alkaline condition the saturated adsorption of three collectors on the argentite surface ranked in this order: ADD>EX>DDTC,suggesting that ADD has preferable adsorption ability on the argentite surface and should be chosen for argentite flotation.%单矿物浮选实验结果表明,辉银矿在pH为9～10的弱碱性介质下可浮性较好,而在pH大于 11 的强碱介质下可浮性明显降低.通过热力学计算了乙基黄药、丁铵黑药和乙硫氮浮选辉银矿的临界pH分别为9.38、9.11和11.59.上述3种捕收剂在辉银矿表面的吸附量测定结果表明,弱碱性介质中各捕收剂在辉银矿表面的吸附量已经达到最大值,进一步增加 pH,吸附量会大幅降低,这可能是由于辉银矿表面在强碱性介质中先生成了氢氧化银沉淀,后进一步水解生成了亲水性的氧化银薄膜,阻碍了捕收剂与辉银矿的吸附过程,从而导致辉银矿可浮性降低.此外,弱碱性介质中3种捕收剂在辉银矿表面的饱和吸附量排序为丁铵黑药>乙基黄药>乙硫氮,表明丁铵黑药更易吸附在辉银矿表面,对银矿物具有更好的捕收性能.