Gasser M S, El-Hefny N E, Daoud J A
Hot Laboratories Centre, Atomic Energy Authority, Post Code 13759, Cairo, Egypt.
J Hazard Mater. 2008 Mar 1;151(2-3):610-5. doi: 10.1016/j.jhazmat.2007.06.032. Epub 2007 Jun 14.
The extraction equilibrium of Co(II) from thiocyanate medium by CYANEX 923 (mixture of straight chain alkylated phosphine oxides) in cyclohexane was studied. The stoichiometry of the extraction reaction was postulated based on slope analysis method and the extraction constant Kex was calculated. The stripping percentage of Co(II) with sulphuric acid from the loaded CYANEX 923 was found to increase with the increase in acid concentration. The extraction of Co(II) from aqueous thiocyanate medium into emulsion liquid membrane using CYANEX 923 extractant was also studied. The influence of different parameters such as stirring speed, surfactant concentration, pH of the extractant phase, carrier concentration, internal phase stripping acid concentration, initial Co(II) concentration as well as temperature on the emulsion stability were investigated. The applicability of the emulsion liquid membrane (ELM) process using CYANEX 923 as extractant and SPAN 80 as surfactant for the removal and the concentration of Co(II) from thiocyanate solution was investigated. The results show that it is possible to recover 95% of cobalt in the inner phase after 10 min of contacting time with a concentration factor of 5.
研究了用CYANEX 923（直链烷基化氧化膦混合物）从硫氰酸盐介质中在环己烷中萃取Co(II)的平衡。基于斜率分析法推测了萃取反应的化学计量关系，并计算了萃取常数Kex。发现用硫酸从负载的CYANEX 923中反萃Co(II)的反萃率随酸浓度的增加而增加。还研究了用CYANEX 923萃取剂从硫氰酸盐水溶液介质中萃取Co(II)到乳状液膜中的过程。研究了搅拌速度、表面活性剂浓度、萃取剂相的pH值、载体浓度、内相反萃酸浓度、初始Co(II)浓度以及温度等不同参数对乳液稳定性的影响。研究了以CYANEX 923为萃取剂、SPAN 80为表面活性剂的乳状液膜（ELM）工艺用于从硫氰酸盐溶液中去除和浓缩Co(II)的适用性。结果表明，接触10分钟后，内相中钴的回收率可达95%，浓缩因子为5。
