铜溶剂萃取界面乳化物极限聚结机理

Mechanism of limited coalescence of interfacial emulsion in copper solvent extraction

为解决德兴铜矿生物浸出溶剂萃取电积铜生产的萃取界面乳化问题 ,研究了界面乳化物的稳定性。实验结果表明 :界面乳化物陈化时产生极限聚结现象 ,液滴平均粒径增加到极限值 13～ 14μm时不再变化 ,聚结过程停止而使乳化物长期稳定性很高 ;双电层作用使液滴界面区介质的介电常数远低于体相溶液的介电常数 ,促使硫酸盐沉淀自乳化物连续相中析出 ,并不断在液滴表面沉积使界面膜逐渐变厚 ,同时界面效应也使连续相中Fe(OH) 3 和SiO2 胶体结构不断聚合 ,使乳化物胶凝化 ,液滴的聚结变得越来越难 ,最终出现极限聚结现象。计算结果表明 ,一些硫酸盐的界面溶解度比体相中的溶解度低近

The serious interface emulsion created in the copper solvent extraction operation of Dexing Copper Mine influences adversely the whole bioleaching-solvent extraction-electrowinning process. To solve this problem the stability of interfacial emulsion was researched. It is discovered that limited coalescence of emulsion droplets takes place during the emulsion storage, which results in the stabilization of average diameter of droplets at 13～14?μm. Droplets can not coalesce and the emulsion can keep a long-term. Sulfate precipitation is promoted in interfacial region where the medium dielectric constant is relatively lower due to the effect of electrical double layer. The sedimentation of precipitates on droplet interface makes the interfacial skins become more and more thick and the coalescence become more and more difficult. Interfacial effects make the colloids of Fe(OH) 3 and SiO 2 in aqueous phase polymerize continuously, so that the emulsion gelates gradually. As a result limited coalescence of droplets takes place. Calculated interfacial solubility of some sulfates is lower by about 10 times than that in continuous body phase.