熔体NH_4Cl与Li_2CO_3反应的研究

Study on the Reaction of Li_2CO_3 with NH_4Cl with Thermoanalysis Methods

在理论上对NH4Cl与Li2CO3的反应进行了热力学计算,计算结果表明在100℃以下此反应不能进行.随着温度的升高,反应的自由能迅速负移,平衡常数增大.从计算结果可以断定,当反应温度达到150℃以上时,如果动力学条件允许,反应可以进行完全.在此基础之上利用一系列热分析方法仔细研究了NH4Cl与Li2CO3的热反应过程以及转化率,结果证明在惰性气体的保护下,NH4Cl∶Li2CO3=4∶1(mol)时,Li2CO3在加热至200℃开始与NH4Cl反应,当体系温度达到328℃时,Li2CO3定量转化为LiCl,转化率近似为100%.过量的NH4Cl在400℃以下全部分解.这一结论可以大大简化LiCl体系的熔盐电解的前期处理,并且可以预期在LiCl体系的熔盐相图上及其它物化性质的测定上均具有广泛的应用前景.

The chlorinating reaction of Li2CO3 with NH4Cl has been studied by a series of thermoanalysis methods in details. When the mole ratio of NH4Cl to Li2CO3 equals 4, Li2CO3 can be turned into LiCl quantitatively and all residual NHaCl has been decomposed under 400℃. It is interested that the chlorination reaction can be applied to the measurement of some phase diagrams concerning LiCl.