钒铬萃取分离过程中界面乳化物的形成行为

来源期刊:中国有色金属学报2009年第4期

论文作者:宁朋歌 曹宏斌 林晓 张懿

文章页码:773 - 778

关键词:钒;铬;萃取;界面乳化物

Key words:V; Cr; extraction; interfacial crud

摘    要:研究了初始pH值、萃取剂浓度、萃取剂类型、稀释剂类型、平衡时间和料液预处理方式等因素对界面乳化物形成行为的影响,采用扫描电镜、X射线能谱仪及X射线衍射等手段分析了界面乳化物中固体微粒的组成。结果表明:能够最大程度避免界面乳化物生成的工艺条件为初始pH值4~6,以萃取剂为LK-N21且萃取剂浓度15%(体积分数),稀释剂为正己烷,萃取时间5 min;采用0.22 μm的滤膜对料液过滤两次再萃取,不出现界面乳化物;界面乳化物的形成机制可能为在震荡混合萃取过程中,料液中的二氧化硅胶体等不溶性物质,在乳化液滴表面形成致密的固体膜,稳定了乳化液;可溶性无机盐在乳化液界面结晶出来,进一步稳定了乳化液,形成比较稳定的界面乳化物。

Abstract: The effects of initial pH, extractant concentration, extractant, diluent and equilibrium time on the formation behavior of the interfacial crud produced in extraction separation of V and Cr by primary amine was investigated. Both scanning electron microscopy with X-ray energy spectrum and X-ray diffractometry were used to characterize the solids in crud and elucidate the formation mechanism of crud. The initial pH value of 4-6, 15% (volume fraction) LK-N21, n-hexane as diluent and extraction time of 5 min are optimal conditions, which can eliminate the crud as much as possible. Moreover, no crud appears after filtering feed solution twice by 0.22 μm fiber membrane. The insoluble particles in feed solution, such as SiO2, form a surface film by providing sterichindrance to drop-drop coalescence and stabilize the interfacial emulsion, which attribute to the crystallization of sodium sulfate. The crystal from insoluble particles increases the stabilization of emulsion again, and then the interfacial crud forms.

基金信息:国家高技术研究发展计划资助项目
中国科学院知识创新工程重要方向资助项目

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