微量热法研究白钨矿在NaOH溶液中的溶解及其与油酸钠作用的热动力学  

Dissolution of Scheelite in NaOH Solution and its Interaction with Sodium Oleate by Microcalorimetry

作　　者：匡敬忠[1] 马强 刘鹏飞[1] 黄哲誉 Kuang Jingzhong;Ma Qiang;Liu Pengfei;Huang Zheyu(Faculy of Resource and Enironmental Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China)

机构地区：[1]江西理工大学资源与环境工程学院,江西赣州341000

出　　处：《稀有金属》2021年第3期322-332,共11页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51664019)资助。

摘　　要：采用微量热法研究了白钨矿在NaOH溶液中的溶解及其与油酸钠作用的热动力学,并通过扫描电子显微镜(SEM)、总有机碳(TOC)及傅里叶变换红外光谱(FTIR)对白钨矿在NaOH溶液体系中的溶解特性及其与油酸钠的作用方式进行表征,同时进行了单矿物浮选试验研究。结果表明:白钨矿在NaOH溶液中溶解为吸热反应,反应级数n=3,pH=10时溶解反应热最大,溶解反应热与Ca^(2+)浓度成正相关。白钨矿表面Ca^(2+)在NaOH溶液中吸附油酸根离子为放热反应,反应级数n=1,相对白钨矿溶解发生了热量转变,不同pH条件下的吸附反应热大小与白钨矿溶解反应热趋势一致,在pH=12时反应速率均较快。不同pH条件下油酸根离子的吸附量与其反应热大小成正比,这与单矿物浮选结果一致。Microcalorimetry was an on-line and non-destructive method for the determination of thermal effects. The change of enthalpy and specific heat caused by the reaction of material was measured and analyzed by microcalorimeter,and the corresponding thermodynamic and kinetic parameters were obtained to study the reaction process. At present,there were few reports on the dissolution and adsorption of scheelite under alkaline conditions by microthermal method. Therefore,the study of the thermodynamic and kinetic parameters of the dissolution and surface adsorption of scheelite under alkaline conditions by microthermal method had important theoretical guiding significance. The scheelite used in this study were a synthetic one,and the Na2WO4 and Ca(NO3)2 used in the synthesis of scheelite were both analytically pure. The pH regulators were NaOH and its purity was analyzed. The collector was sodium oleate,analytically pure. The experimental water was ultrapure water. The trace thermal kinetics of scheelite dissolution and scheelite adsorption sodium oleate were tested by Microcalorimeter. The absorption quantity of sodium oleate on scheelite surface was tested by adsorption experiment. The structure transformation of scheelite surface was tested by Fourier infrared spectrum analysis and verified by flotation experiment. The results mainly included the following five parts:(1)It could be seen that the dissolution of scheelite in NaOH solution was endothermic reaction. At pH=10,the integral area of the heat rate curve(heat of reaction)was at its maximum Q=-24.38 mJ,and at pH=12,the minimum heat of reaction Q=^(-1)8.99 mJ. The order of the reaction heat dissolved in NaOH solution of scheelite was pH=10>pH=11>pH=9>pH=8>pH=12. In short,the reaction rate constant(k)tended to decrease first and then increase. When pH=12,the reaction rate constant reached its maximum. The reaction order(n)was approximately equal to 3,indicating that scheelite wasdissolved in NaOH at different pH values as a third-order reaction.(2)D50 changed with

关 键 词：微量热法 热动力学 白钨矿 油酸钠 溶解 吸附 

分 类 号：TD954[矿业工程—选矿]