(中南大学 冶金科学与工程学院， 长沙 410083)
摘 要: 针对从钨矿碱性浸出液中直接萃取钨制取仲钨酸铵(APT)工艺萃取分相慢、反萃液中WO3浓度偏低的问题，采用季铵盐三辛基甲基氯化铵(Tri-n-octylmethyl-ammonium chloride,TOMAC)为萃取剂，对从钨矿苏打浸出模拟料液中直接萃取钨进行研究，分别考察钨矿浸出液中Na2CO3浓度、反萃剂组成及浓度对萃取和反萃取过程的影响；分别绘制萃取等温线和反萃取等温线，并结合Kremser方程选择合适的反萃流比以及逆流反萃级数，用离心萃取器模拟逆流串级萃取与反萃取实验。结果表明：料液中Na2CO3浓度对WO3萃取率影响不大，但对萃取过程分相性能影响较大；当萃取剂浓度为50%(体积分数)时，有机相饱和萃钨容量(以WO3计)为91.49g/L；向反萃剂NH4HCO3中加入NH3·H2O，不仅能提高反萃液(钨酸铵溶液)的稳定性，而且有利于提高反萃液中WO3的浓度。实验条件下分相良好，反萃液中WO3浓度达到160 g/L左右，杂质含量完全可以满足生产0级APT的需要。
关键字: 钨；溶剂萃取；季铵盐；Na2CO3体系
leaching liquor of scheelite with quaternary ammonium salt
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The direct solvent extraction of tungsten from autoclave-soda leach solution of scheelite using quaternary ammonium salt (tri-n-octylmethy-lammonium chloride, TOMAC) was investigated to solve the problems of slow phase separation and low WO3 concentration in strip liquor which are main disadvantages in the process of direct solvent extraction of tungsten from alkaline medium. The effects of Na2CO3 concentration in leaching solution, composition and concentration of stripping reagent on the extraction and stripping were investigated. The isotherms of the extraction and stripping were plotted, and the optimum flow ratio and stripping stage were determined through Kremser formula. Based on these, the centrifugal extractor was used to simulate the counter current extraction. The results indicate that the concentration of Na2CO3 in feed solution has little influence on the extraction of WO3 but great influence on the phase separation in the extraction, the saturated loading capacity (for WO3) of organic reaches 91.49 g/L when the concentration of extractant is 50%( volume fraction), the addition of NH3∙H2O into NH4HCO3 as the mixed stripping reagent not only improves the stability of stripping liquor, but also increases the WO3 concentration in stripping liquor. The phase separation is good during the extraction and stripping, and the concentration of WO3 in stripping liquor reaches about 160 g/L. The stripping liquor can be used to produce APT of 0 grade of national standards of China.
Key words: tungsten; solvent extraction; quaternary ammonium salt; Na2CO3 system
