白云鄂博稀土焙烧矿浸出动力学研究  

Leaching Kinetics of Rare Earth Roasted Ore in Bayan Obo

作　　者：耿金龙[1,2,3] 李梅 张栋梁[1,3] 高凯 徐伟[2,3] 王慧惠[3] Geng Jinlong;Li Mei;Zhang Dongliang;Gao Kai;Xu Wei;Wang Huihui(School of Material and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,China;School of Chemistry and Chemical Engineering,Inner Mongolia University of Science and Technology,Baotou 014010,China;Key Laboratory of Green Extraction&Efficient Utilization of Light Rare-Earth Resources,Ministry of Education,Baotou 014010,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010 [2]内蒙古科技大学化学与化工学院,内蒙古包头014010 [3]轻稀土资源绿色提取与高效利用教育部重点试验室,内蒙古包头014010

出　　处：《稀有金属》2020年第2期178-185,共8页Chinese Journal of Rare Metals

基　　金：国家自然科学基金重点项目(51634005);国家自然科学基金项目(51564042);内蒙古自治区自然科学基金重大项目(2014ZD04,2016ZD05)资助。

摘　　要：以白云鄂博高品位稀土精矿为研究对象,对稀土精矿进行NaOH-Na2CO3焙烧,详细研究了焙烧矿中稀土在盐酸浸出过程中的化学与物理机制,分析动力学相关影响因素,确定了动力学浸出模型;结果表明:当HCl浓度4.0 mol·L-1,液固比(L/S) 4.5∶1.0,搅拌速度250 r·min-1,浸出温度90℃,酸浸时间为25 min时,稀土浸出率为93.2%,盐酸浓度和浸出温度为化学反应过程主要影响因素。根据扫描电镜(SEM)和X射线衍射(XRD)结果:稀土精矿与焙烧助剂NaOH-Na2CO3在660℃焙烧90 min,矿物中氟碳铈矿和独居石分解为稀土氧化物, Ce(III)被氧化为Ce(IV),焙烧矿盐酸浸出残渣中有少量未分解REPO4和残留的CaF2。计算出稀土元素表观活化能为37.52 kJ·mol-1, HCl浓度和液固比反应级数分别为2.446和2.226;根据焙烧矿中稀土浸出动力学相关试验数据推导出浸出模型为一种收缩核模型变体,化学反应过程受产物层界面传质和扩散共同作用。The high-grade rare earth concentrate of Bayan Obo was used as the research object, and the rare earth concentrate was roasted by NaOH-Na2CO3. The chemical and physical reaction mechanism of rare earth in the process of hydrochloric acid leaching in roasted ore was studied in detail. The influencing factors of kinetics were analyzed and the kinetic leaching model was determined. The results showed that when the HCl concentration was 4.0 mol·L-1, the liquid-solid ratio(L/S) was 4.5∶1.0, the stirring speed was 250 r·min-1, the leaching temperature was 90 ℃, and the acid leaching time was 25 min, the rare earth leaching rate was 93.2%. Hydrochloric acid concentration and leaching temperature were the main influencing factors of chemical reaction process. According to scanning electron microscopy(SEM) and X-ray diffraction(XRD) results, the rare earth concentrate and roasting additive NaOH-Na2CO3 were roasted at 660 ℃ for 90 min. The bastnaesite and monazite in the mineral were decomposed into rare earth oxides, and Ce(III) was oxidized to Ce(IV). The hydrochloric acid leaching residue of the roasted ore contained a small amount of undecomposed REPO4 and residual CaF2. The apparent activation energy of rare earth elements was calculated to be 37.52 kJ·mol-1, and the HCl concentration and liquid-solid ratio reaction order were 2.446 and 2.226, respectively. According to the experimental data of rare earth leaching kinetics in roasted ore, the leaching model was deduced as a shrinking core model variant, the chemical reaction process was affected by mass transfer and diffusion at the interface of the product layer.

关 键 词：表观活化能 高品位 稀土 焙烧矿 动力学 

分 类 号：TF84[冶金工程—有色金属冶金]