摘要
电镀污泥酸性浸出液中的铬铁分离是影响铬资源化回收的一大技术难题。目前已开发的磷酸盐选择性沉淀法分离效果好、操作简单，是一种具有发展前景的铬铁分离工艺。研究有关该体系沉淀过程的相关理论对于寻找最佳工作条件具有重要的指导意义。通过热力学计算，绘制了25℃时Cr^3＋-Fe^3＋-PO4^3-H2O系和Cr^3＋-Fe^2＋-PO4^--H2O系的热力学平衡图，并考察了磷酸盐加入量和溶液中总铁浓度等相关参数对分离效果的影响。结果表明：在酸性溶液中，采用磷酸盐沉淀法分离Cr^3＋和Fe^3＋是不可行的；而在Cr^3＋-Fe^2＋-PO4^--H2O系中，CrPO4（s）单独稳定区的存在，为Cr^3＋和Fe^2＋的分离提供了一条途径；通过热力学分析，获得了Cr^3＋和Fe^2＋分离的最佳工作窗口。结合已有研究，进一步验证了理论计算的准确性。
Separation of chromium and iron from acidic lixivium of electroplating sludge is a problem in the recovery of chromium. The selective phosphate precipitation is a promising method to separate Cr and Fe due to the characters of effective separation and sim- ple operation. Therefore, the study of related theory of the precipitation process is vital for optimizing operation conditions. According to thermodynamic calculation, the equilibrium diagrams of Cr^3＋-Fe3＋-PO4^3-H2O system and Cr^3＋ -Fe^2＋ -PO4 -H2O system were estab- lished at 25℃. The effect of phosphate dosage and initial iron concentration on the separation was also investigated. The results indi- cated that it was in feasible to separate Cr^3＋ and Fe^3＋ by phosphate precipitation. By contrast, there existed a stable region of CrPO4（s） in Cr^3 ＋ Fe^2 ＋ FO4^3 - -Fe -PO4 -H2O system, which provided an approach for separation Cr3＋ and Fe2＋ Through thermodynamic analysis, the optimal operating window was obtained. Furthermore, the existing works further illustrated the correctness of the theoretic calculation.
作者
张文娟
马保中
王成彦
Zhang Wenjuan;Ma Baozhong;Wang Chengyan(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2018年第10期1084-1092,共9页
Chinese Journal of Rare Metals
基金
中国博士后科学基金项目(2017M610766)
中国博士后科学基金特别资助项目(2018T110045)资助
中央高校基本科研业务费项目(FRF-TP-17-037A1,FRF-BD-17-010A)
关键词
铬铁分离
磷酸盐沉淀法
热力学
Cr/Fe separation
phosphate precipitation
thermodynamic
