摘要
针对高铬钒渣中钒铬尖晶石结构稳定、传统钠化焙烧工艺钒铬共溶分离困难的问题,提出一种钙改性驱动的钠化焙烧新策略。通过引入CaO调控钠盐焙烧体系,探究CaO与Na_(2)CO_(3)质量比对钒、铬赋存形态及分离效率的影响。研究结果表明:当只添加Na_(2)CO_(3)作为焙烧助剂时,可实现钒(浸出率为91.5%)和铬(浸出率为63.2%)的同步浸出;当CaO与Na_(2)CO_(3)质量比为0.67时,钒的浸出率变化不大,而铬的浸出率提高到73.0%,钙离子优先结合硅铝杂质生成高熔点硅酸钙,释放液相中游离Na^(+),促进铬尖晶石深度氧化为可溶性Na_(2)CrO_(4);当CaO与Na_(2)CO_(3)质量比增至1时,过量Ca^(2+)通过配位重构将钒转化为Ca_(2)V_(2)O_(7)和NaCaVO_(4)等难溶钙钒酸盐,而铬仍以可溶性Na_(2)CrO_(4)形式优先浸出;在水浸过程中,钒浸出率为6.28%,铬浸出率为72.26%,在碳酸氢铵浸出过程中,钒浸出率为83.84%,铬浸出率为13.35%,实现了钒铬的选择性提取与分离。
To address the challenges of stable vanadium-chromium spinel structures in high-chromium vanadium slag and the difficulty in separating co-dissolved vanadium and chromium via traditional sodium roasting processes,a novel calcium-modified sodium roasting strategy was proposed.By introducing CaO to modulate the sodium salt roasting system,the effects of different mass ratios of CaO and Na_(2)CO_(3)on the speciation and separation efficiency of vanadium and chromium were systematically investigated.The results show that when only Na_(2)CO_(3)is used as the roasting additive,synchronous leaching of vanadium(91.5%)and chromium(63.2%)are achieved.When the mass ratio of CaO and Na_(2)CO_(3)is 0.67,the vanadium leaching efficiency remains stable,while the chromium leaching efficiency increases to 73.0%.Calcium ions are combined with silica-alumina impurities to form high-melting-point calcium silicate,releasing free Na^(+)ions within the liquid phase and promoting the deep oxidation of chromium-bearing spinel to soluble sodium chromate(Na_(2)CrO_(4)).When the mass ratio of CaO and Na_(2)CO_(3)is increased to 1,excess Ca^(2+)induces coordination reconstruction,converting vanadium into insoluble calcium vanadates(e.g.,Ca_(2)V_(2)O_(7)and NaCaVO_(4)),while chromium remains predominantly leached as soluble Na_(2)CrO_(4).During the water leaching stage,the vanadium leaching rate is 6.28%,while the chromium leaching rate reaches 72.26%.In the NH_(4)HCO_(3)leaching stage,vanadium leaching rate is 83.84%,and chromium leaching rate is 13.35%,achieving the selective vanadium-chromium extraction and separation.
作者
赵卫夺
徐颖鹏
李江涛
刘旭恒
赵中伟
ZHAO Weiduo;XU Yingpeng;LI Jiangtao;LIU Xuheng;ZHAO Zhongwei(School of Environment and Metallurgy,Central South University,Changsha 410083,China;Hunan Key Laboratory of Rare Metal Metallurgy and Materials Preparation,Changsha 410083,China)
出处
《中南大学学报(自然科学版)》
北大核心
2025年第8期3117-3125,共9页
Journal of Central South University:Science and Technology
基金
国家自然科学基金基础科学中心项目(72088101)
国家自然科学基金重大项目(52494945)。
关键词
高铬钒渣
钠化焙烧
钙改性
钒铬分离
选择性提取
配位重构
high-chromium vanadium slag
sodium roasting
calcium-modified
vanadium chromium separation
selective extraction
coordination reconstruction
