(1. 中国科学院 过程工程研究所 湿法冶金清洁生产技术国家工程实验室,北京 100190;
2. 中国矿业大学(北京) 化学与环境工程学院,北京 100083)
摘 要: 针对钒渣在NaOH低温亚熔盐体系中铬无法溶出问题,提出添加活性炭增加介质氧含量强化铬氧化溶出方法,并考察活性炭种类、活性炭添加量、活性炭粒度、温度对钒、铬溶出率的影响。结果表明,在NaOH亚熔盐体系中添加活性炭可有效促进钒和铬的溶出,活性炭种类和温度是最重要的影响因素;在反应温度215 ℃、碱与矿质量比6:1、通氧量1 L/min、搅拌速度900 r/min、椰壳活性炭添加量10%的条件下,反应进行600 min后钒、铬溶出率分别达到97%和90%。动力学分析表明,添加活性炭后钒渣的氧化分解受界面化学反应控制,钒、铬尖晶石分解反应的表观活化能分别为54.79和411.15 kJ/mol;活性炭起物理吸附氧气作用。
关键字: 钒渣;亚熔盐法;活性炭;钒;铬;提取;动力学分析;活化能
(1. Key Laboratory of Green Process and Engineering, Institute of Process Engineering,
Chinese Academy of Sciences, Beijing 100190, China;
2. School of Chemical and Environmental Engineering,
China University of Mining and Technology of Beijing, Beijing 100083, China)
Abstract:For chromium in vanadium slag cannot be dissolved in low temperature NaOH sub-molten salt (SMS) system, the method adding activated carbon to increase medium oxygen content to strengthen chromium oxide dissolution was proposed, and the effects of activated carbon type, the amount of activated carbon added, activated carbon particle size, reaction temperature on the dissolution of vanadium and chromium were studied. The results suggest that the activated carbon can improve the dissolution of vanadium and chromium effectively. The activated carbon type and reaction temperature are the main affecting factors. Under the optimal reaction conditions (temperature of 215 ℃, NaOH-to-ore mass ratio of 6:1, gas flow of 1 L/min, stirring speed of 900 r/min, coconut shell activated carbon addition of 10%, and reaction time of 600 min), vanadium and chromium extraction rates can reach 97% and 90%, respectively. The kinetics analysis suggests that vanadium oxidation decomposition in SMS is controlled by surface chemical reaction, and the apparent activation energies for vanadium and chromium are 54.79 and 411.15 kJ/mol, respectively. The effect of activated carbon is physical adsorption of oxygen.
Key words: vanadium slag; sub-molten salt method; activated carbon; vanadium; chromium; extraction; kinetics analysis; activation energy