Abstract

A relationship has been found between the structure of microemulsions based on sodium dodecyl sulfate (SDS) and sodium di-(2-ethylhexyl)phosphate (D2EHPNa) and the efficiency of microemulsion leaching of copper. The dependences of electrical conductivity on the volume fraction of water have been studied for microemulsions containing D2EHPNa or a mixture of SDS and butanol, decane, water, and di-(2-ethylhexyl)phosphoric acid as an extractant for copper extraction. A gradual passage from water-in-oil microemulsions with the predominance of isolated droplets to microemulsions with the predominance of dynamic clusters of droplets (percolated structure) takes place with the increase in the volume fraction of water. The conductivity percolation thresholds are approximately 0.18 and 0.20 for the microemulsions based on D2EHPNa and SDS, respectively. The temperature dependence of the logarithmic electrical conductivity is linear in a range of 20–80°C for the microemulsions with water volume fractions below (0.13 and 0.07, respectively) and above (0.30 and 0.23) the percolation threshold; in this temperature range the structure of the considered microemulsions remains unchanged. The experiments on microemulsion leaching performed with the use of a CuO-based model system at T = 80°C have shown that, for the microemulsions with the percolated structure (having water volume fractions of 0.30 for D2EHPNa microemulsions and 0.23 for SDS microemulsions), copper extraction is higher than that for the microemulsions with the predominance of isolated droplets (water volume fraction of 0.13 and 0.07, respectively).

中文翻译：

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磷酸二(2-乙基己基)钠和十二烷基硫酸钠油包水微乳液结构对微乳液浸铜效率的影响

摘要

已经发现基于十二烷基硫酸钠（SDS）和磷酸二（2-乙基己基）钠（D2EHPNa）的微乳液的结构与微乳液浸出铜的效率之间存在关系。研究了含有 D2EHPNa 或 SDS 和丁醇、癸烷、水和二-(2-乙基己基)磷酸的混合物作为铜萃取剂的微乳液的电导率对水体积分数的依赖性。随着水体积分数的增加，从以孤立液滴为主的油包水微乳液逐渐过渡到以动态液滴簇（渗透结构）为主的微乳液。基于 D2EHPNa 和 SDS 的微乳液的电导率渗透阈值分别约为 0.18 和 0.20。对于水体积分数低于（分别为 0.13 和 0.07）和高于（0.30 和 0.23）渗透阈值的微乳液，对数电导率的温度依赖性在 20-80°C 范围内呈线性；在此温度范围内，所考虑的微乳液的结构保持不变。使用 CuO 基模型系统在T = 80°C 下进行的微乳液浸出实验表明，对于具有渗滤结构的微乳液（D2EHPNa 微乳液的水体积分数为 0.30，SDS 微乳液的水体积分数为 0.23），铜的萃取率高于以孤立液滴为主的微乳液（水体积分数分别为 0.13 和 0.07）。