碳还原硫酸锶反应的热力学分析

Thermodynamics analysis on carbon reducing reaction of strontium sulfate

研究了碳还原法制备碳酸锶过程中碳还原反应的机理。通过热重分析初步确定了主反应发生的温度范围在800～1100℃，选用Gibbs—Helmholtz方程、Van’t Hoff方程和Kirchhoff方程对反应过程中的热力学函数随温度的变化情况进行了探讨，从而判断该反应过程的反应机理。对影响反应的反应时间、反应温度、反应物粒度这3个因素进行了考察。结果表明，反应温度越高，反应物粒度越小，反应速度越快，反应时间越短；但反应温度过高、反应时间过长均不利于反应的进行。适宜的反应条件为：反应温度为1050℃，反应时问为45min，反应物粒度为130μm。在此条件下，水溶性锶产率达到92．87％。

Mechanism of carbon reducing reaction in preparing strontium carbonate by carbon reducing method was studied. Thermodynamics functions of possible reactions at proposed temperature were calculated through Gibbs - Helmhohz,Van＇t Hoff,and Kirchhoff equations, and the range of main reaction temperature was preliminarily determined between 800℃ and 1 100℃ through thermogravimetric analysis ,by which mechanism of carbon reducing reaction in the preparation of strontium carbonate was explained. Then the influencing factors, including time, temperature, and particle size of reactants of reaction process were studied. Results showed that high temperature, and small particle size were conducive to improving the productive rate and to shortening reaction time. Whereas overhigh temperature and overlong reaction time were both not propitious for further reaction. The optimum reaction conditions ： temperature was 1 05℃, time was 45 min, and particle size was 130μm. The productive rate of soluble strontium could reach 92.87% under those conditions.