不同气氛下白云鄂博铌铁矿固相转化热力学研究  

Thermodynamics study on solid-phase transformation of columbite in Bayan Obo deposit under different atmospheres

作　　者：卢翔 陈雯[1,2] 姜楚灵 LU Xiang;CHEN Wen;JIANG Chu-ling(Changsha Research Institute of Mining and Metallurgy,Co.,Ltd.,Changsha 410012,China;School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China)

机构地区：[1]长沙矿冶研究院有限责任公司,长沙410012 [2]中南大学资源加工与生物工程学院,长沙410083

出　　处：《中国有色金属学报》2023年第3期922-930,共9页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金重点资助项目(92062223);国家重点研发计划资助项目(2020YFC1909103,2021YFC2901200)。

摘　　要：将白云鄂博多种典型铌矿物调控为单一矿相有利于铌的选矿富集。本文利用双参数模型计算了典型铌矿物热力学参数,以此计算不同气氛下白云鄂博白云岩环境中铌铁矿固相转化反应的Gibbs自由能。结果表明:反应温度区间为400~1500 K时,惰性气氛下铌铁矿可自发转化为KNbO_(3)、NaNbO_(3)、Ca_(2)Nb_(2)O_(7)和CaNb_(2)O_(6),生成NaNbO_(3)的反应趋势大于生成Ca_(2)Nb_(2)O_(7)(烧绿石)。铌铁矿碳热还原产物生成趋势顺序为:Nb_(2)O_(5)→NbO_(2)→NbC。当反应温度大于1047 K后,碳热还原会促进铌铁矿固相转化反应的进行;当反应温度处于1047~1435 K时,铌铁矿固相转化为烧绿石的反应趋势大于还原反应;当反应温度大于1435K后,铌铁矿还原为NbC的反应趋势大于固相转化反应。因此,碳热还原气氛促进铌铁矿转化为烧绿石,且不继续还原为NbC的热力学理论温度范围为1047~1435 K。Regulating a variety of typical niobium minerals into a single mineral phase benefits niobium enrichment in Bayan Obo.In this paper,the thermodynamic parameters of typical niobium minerals were calculated by two-parameter model.The reaction Gibbs free energy of columbite in the coarse concentrate of Bayan Obo deposit was calculated under different atmospheres.The results show that columbite can be spontaneously converted into KNbO_(3),NaNbO_(3),Ca_(2)Nb_(2)O_(7) and CaNb_(2)O_(6),respectively,in inert atmosphere.However,the NaNbO_(3) is superior to Ca_(2)Nb_(2)O_(7) by considering reaction tendency when the reaction temperature increases from 400 K to 1500 K.The formation tendencies order of carbothermal reduction products of columbite are Nb_(2)O_(5),NbO_(2) and NbC by thermodynamic calculation.Carbothermal atmosphere benefits solid-phase transformation of columbite when the reaction temperature is higher than 1047 K.The reaction tendency of columbite-to-pyrochlore conversion have priority over that of the reduction at the temperature ranging from 1047 K to 1435 K.The reaction tendency of the reduction of columbite into NbC is superior at the temperature over 1435 K..Therefore,the theoretical temperature range of columbite transforming into Ca_(2)Nb_(2)O_(7) rather than NbC is from 1047 K to 1435 K.

关 键 词：铌铁矿 双参数模型 碳热还原 固相转化 热力学分析 

分 类 号：TF841.6[冶金工程—有色金属冶金]