黑钨渣中有价金属碳热还原动力学研究  

Study on Kinetics of Carbothermic Reduction of Valuable Metals in Wolframite Slag

作　　者：曾智勇 廖春发[1] 谢岁 邓攀[1] ZENG Zhiyong;LIAO Chunfa;XIE Sui;DENG Pan(Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,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

出　　处：《中国钨业》2023年第3期55-65,共11页China Tungsten Industry

基　　金：国家重点研发计划“固废资源化”专项(2019YFC1907404);江西省重点研发计划项目(20192ACB70008);赣州市星火计划项目(赣市研发[2019]60号)。

摘　　要：钨精矿碱浸过程中产生大量钨渣,赋含铁、锰、钨和铌等多种有价金属,采用碳热还原制备成合金是回收钨渣中有价金属的重要方法。为探明钨渣的还原规律,本文采用等温还原研究了黑钨渣的碳热还原动力学,研究了在高温下反应时间、温度对金属还原的影响,研究了各主要金属还原的表观活化能和还原动力学方程及其控制环节。结果表明:采用还原剂为石墨、碳氧摩尔比为1∶1、还原温度为1873 K、反应时间为60 min时,黑钨渣中金属还原度为70.54%,铁、锰、钨和铌的还原度分别为93.18%、38.94%、94.07%和84.10%,温度升高有利于黑钨渣的还原。还原温度为1673~1873 K、时间为0~12.5 min时反应受界面化学反应控制,界面化学反应控制阶段还原度a与反应时间t的关系为1-(1-a)^(1/3)=kt;时间为0~12.5 min时还原反应受扩散控制,扩散控制阶段还原度a与反应时间t的关系为[(1-a)^(-1/3)-1]^(2)=kt,黑钨渣还原的表观活化能分别为137.30 kJ/mol、573.92 kJ/mol。A large amount of tungsten slag with high content of valuable metals such as iron,manganese,tungsten and niobium,is generated during the alkali leaching process of tungsten concentrate.The preparation of alloy from tungsten slag by carbothermal reduction is an important method to recover these valuable metals.In order to explore the reduction law of tungsten slag,the carbothermal reduction kinetics of wolframite slag by isothermal reduction was studied.The effects of reaction time and temperature on metal reduction at high temperatures were investigated.The apparent activation energy,the reduction kinetics equation of metal reduction and its control link were studied.The results show that when the reducing agent is graphite,the molar ratio of carbon to oxygen is 1:1,the reduction temperature is 1873 K,and the reaction time is 60 min,the metal alloying rate of wolframite slag is 70.54%,and the reduction degrees of iron,manganese,tungsten and niobium in slag of wolframite are 93.18%,38.94%,94.07%and 84.10%,respectively.The increase of temperature is beneficial to the reduction of wolframite slag.When the reduction temperature is 1673-1873 K and the reduction time is 0-12.5 min,the reaction is controlled by the interfacial chemical reactions,which conforms to the mechanism function 1-(1-a)^(1/3)=kt.When the reaction time is 0-12.5 min,the reaction is controlled by diffusion,which conforms to[(1-a)^(-1/3)-1]^(2)=kt.The apparent activation energy of the reduction of wolframite slag is 137.30 kJ/mol and 573.92 kJ/mol,respectively.

关 键 词：黑钨渣 碳热还原 动力学 还原机制 

分 类 号：TF805.2[冶金工程—有色金属冶金]