Optimization of preparation of CO₃O₄ by microwave calcination from basic cobalt carbonate

The parameters to prepare of Co₃O₄ by microwave calcination from basic cobalt carbonate were optimized based on the thermal gravity analysis–differential thermal gravity (TG–DTG) using with central composite concept of response surface methodology. A quadratic equation model for decomposition rate was built and rising behaviour of basic cobalt carbonate in fields of microwave and effects of main factors and their corresponding relationships on response were obtained. The results showed that a sample 20% addition of Co₃O₄ with the basic cobalt carbonate has ability to strongly absorb microwave energy, and the calcination temperature and calcination time significantly affect on the decomposition rate of basic cobalt carbonate in this range studied. The decomposition rate of basic cobalt carbonate was 99.56% under optimum calcination temperature 642.65 K, and calcination time 8.89 min and 4.34 g, respectively. The validity of the model was confirmed experimentally and the results were satisfactory. Furthermore, the Co₃O₄ was analysed using X-ray powder diffraction. It was feasible to prepare of Co₃O₄ by microwave calcination from the basic cobalt carbonate though addition of small amounts cobalt oxide.