摘要
研究了白钨矿碱分解过程的热力学和动力学。测定了70℃,90℃及105℃下氢氧化钠溶液与人造白钨反应的平衡浓度商K_c。研究结果表明,该反应的K_c随温度的升高而增大,随碱浓度的升高而明显地增大;105℃下,NaOH浓度为5.68mol/L时,平衡浓度商K_c为0.0259;在70～90℃之间,其反应热为25.80kJ/mol,是一个吸热反应。动力学研究结果证明,反应过程受化学反应控制,反应的表观活化能为58.83kJ/mol,表观反应级数为1.73。升高温度和增大碱浓度都可加快反应速度,强化浸出过程。
The thermodynamics and kinetics of alkaline decomposition of scheelite werestudied. The equilibrium concentration quotients K_c of the reaction of NaOHwith synthetic scheelite at different temperatures were determined. Experimentalresult showed that K_c increases significantly with the elevation of temperatureand the concentration of NaOH. When the concentration of NaOH is 5.68mol/L, K_c is equal to 0.0259 at 105℃. The reaction of scheelite with causticsoda is endothermic, the heat of the reaction being 25.80 kJ/mol in the temperaturerange of 70～90℃. Kinetic study indicated that the caustic alkaline-leaching ofscheelite concentrate is controlled by chemical reaction under the experimentalconditions. The apparent activation energy of the reaction is about 58.83 kJ/mol,and the apparent order of the reaction is about 1.73. Temperature and the con-centration of NaOH have greater influences on the leaching velocity. The increaseof temperature and NaOH concentration will effectively accelerate the rate of theleaching process.
基金
国家自然科学基金
关键词
白钨矿
碱
分解
热力学
动力学
tungsten
scheelite
leaching
thermodynamics
dynamics
