碳酸钴分解的热力学平衡分析和试验研究

Thermodynamic Equilibrium and Experimental Study on Thermal Decomposition of Cobalt Carbonate

为查清碳酸钴的热分解行为和性状遗传特性,对Co-C-O体系的稳定区和碳酸钴在不同气氛下的分解平衡进行了研究。通过热力学分析得到,在无氧状态下CoCO3主要分解为CoO,分解反应是在温度高于200℃时进行;在有氧状态下CoCO3极易发生氧化并分解生成Co3O4,在含氧体积分数为1%的氧气-氮气混合气氛中温度为930℃时Co3O4开始分解为CoO和O2,且分解温度随着系统中氧浓度的增加而降低。CoCO3的热分解试验证实了热力学分析结论,同时表明CoCO3的热分解产物具有一定的性状遗传性,Co3O4的形态依赖于CoCO3的原始形态,分解温度的升高会导致产物结块收缩,使CoO颗粒增大。

In order to investigate the thermal decomposition behaviors of cobalt carbonate and character inheritance of products, the predominance area diagrams of Co-C-O and the decomposition balances of cobalt carbonate in different atmospheres were studied. It was concluded that CoCO3 was mainly decomposed into CoO in the oxygen-free atmosphere and above 200 ℃. In the oxygen atmosphere, the oxidation decomposition reaction of CoCO3 was very easy to occur to generate Co3O4, while it would decompose into CoO and O2 at a temperature higher than 930 ℃, and the decomposition temperature decreased with the increasing of oxygen partial pressure. The thermodynamic analysis conclusion was con?rmed by the veri?cation tests, and there was a character hereditary of the decomposed products in the thermal decomposition process. The shape of Co3O4 depended on that of CoCO3. The increase of decomposition temperature led to the agglomeration and contraction of decomposition products and the particle size increasing of CoO.