粗钨酸钠溶液亚铁盐沉淀法除铬、钒的热力学分析及实验验证  

Thermodynamic analysis and experimental verification of chromium and vanadium removal by ferrous salt precipitation from crude sodium tungstate solution

作　　者：贺山明[1,2] 潘界昌 徐国钻 李文君 梁勇 HE Shanming;PAN Jiechang;XU Guozuan;LI Wenjun;LIANG Yong(Department of Materials Metallurgy Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China;Chongyi Zhangyuan Tungsten Industry Co.,Ltd.,Ganzhou 341300,Jiangxi,China)

机构地区：[1]江西理工大学材料冶金化学学部,江西赣州341000 [2]崇义章源钨业股份有限公司,江西赣州341300

出　　处：《化工进展》2023年第4期2171-2179,共9页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(52064023,51704133);国家级大学生创新创业训练计划(202110407008)。

摘　　要：废硬质合金再生利用过程中得到的粗钨酸盐溶液Cr、V含量容易超标,由于Cr、V与W具有十分相似的水溶液性质,粗钨酸盐溶液除铬、钒一直是个技术难题。本文针对亚铁盐沉淀法从粗钨酸钠溶液中除铬、钒工艺过程进行热力学分析研究,分别绘制了298K时Cr-Fe-H_(2)O体系和V-Fe-H_(2)O体系的Eh-pH图、Cr^(6+)-Fe^(3+)-V^(5+)-H_(2)O体系和Cr^(3+)-Fe^(2+)-Fe^(3+)-V^(5+)-H_(2)O体系的热力学平衡图。热力学分析结果表明:粗钨酸钠溶液中Cr(Ⅵ)在酸性和碱性体系下均能够被Fe^(2+)或Fe(OH)_(2)沉淀还原,V(Ⅴ)则会与Fe^(2+)或Fe(OH)_(2)反应生成Fe(VO_(3))_(2)沉淀;在Cr^(3+)-Fe^(2+)-Fe^(3+)-V^(5+)-H_(2)O体系中存在Fe(VO_(3))^(2+)Fe(OH)^(3+)Cr(OH)^(3+)Fe(OH)_(2)共沉淀稳定区,为亚铁盐沉淀法同时除铬、钒提供了热力学可行性,并获得了沉淀法最佳条件控制区间。验证实验结果表明:控制溶液的pH为9、以n(Fe^(2+))∶n(V+Cr)=15∶1加入硫酸亚铁沉淀剂时,粗钨酸钠溶液的除铬率高达99.85%、除钒率为95.05%、钨损失率仅为0.33%,实验效果与热力学分析结论基本相符;滤渣的SEM-EDS分析结果,进一步证实了Fe-Cr-V共沉淀的技术可行性。The content of Cr and V in the crude tungstate solution obtained in the recycling process of waste cemented carbide is easy to exceed the standard.Because Cr,V and W have very similar properties of aqueous solution,the removal of chromium and vanadium from the crude tungstate solution has always been a technical problem.In this paper,the thermodynamic analysis and research on the process of removing chromium and vanadium from the crude sodium tungstate solution by ferrous salt precipitation method were carried out.The Eh-pH diagrams of Cr-Fe-H_(2)O System and V-Fe-H_(2)O system at 298K and the thermodynamic equilibrium diagrams of Cr^(6+)-Fe^(3+)-V^(5+)-H_(2)O system and Cr^(3+)-Fe^(2+)-Fe^(3+)-V^(5+)-H_(2)O system at 298K were drawn,respectively.Thermodynamic analysis results showed that Cr(Ⅵ)in crude sodium tungstate solution could be reduced by Fe^(2+)or Fe(OH)_(2)precipitation in both acidic and alkaline systems,and V(Ⅴ)would react with Fe^(2+)or Fe(OH)_(2)to form Fe(VO_(3))_(2)precipitation.In Cr^(3+)-Fe^(2+)-Fe^(3+)-V^(5+)-H_(2)O system,there was a stable coprecipitation zone of Fe(VO_(3))^(2+)Fe(OH)^(3+)Cr(OH)^(3+)Fe(OH)_(2),which provided thermodynamic feasibility for the simultaneous removal of chromium and vanadium by ferrous salt precipitation method,and obtained the control range of the best conditions of precipitation method.The experimental results indicated that when the pH value of the solution was controlled to be 9 and ferrous sulfate precipitant was added with n(Fe^(2+))∶n(V+Cr)=15∶1,the chromium removal rate of crude sodium tungstate solution was as high as 99.85%,the vanadium removal rate was 95.05%and the tungsten loss rate was only 0.33%.The experimental effect was basically consistent with the thermodynamic analysis conclusion.The SEM-EDS analysis results of the filter residue further confirmed the technical feasibility of Fe-Cr-V coprecipitation.

关 键 词：亚铁盐沉淀法 热力学分析 钒铬同步脱除 钨酸盐溶液 

分 类 号：TF841.1[冶金工程—有色金属冶金]