THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH
来源期刊：Acta Metallurgica Sinica2007年第3期
论文作者：S.L. Zheng Z. Sun J.Y. Zhang Y. Zhang
Key words：chromite; KOH; thermodynamics; decomposition;
Abstract: Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature,which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.
S.L. Zheng1，Z. Sun1，J.Y. Zhang3，Y. Zhang3
(1.Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080, China;
2.Graduate University of the Chinese Academy of Sciences, Beijing 100049, China;
3.Mechanical Engineering College, Tianjin University of Technology,Tianjin 300191,China)
Abstract:Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature,which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.
Key words:chromite; KOH; thermodynamics; decomposition;
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