**Thermodynamics of Reactions Among Al2O3, CaO, SiO2 and Fe2O3 During Roasting Processes**

Zhongping Zhu, Tao Jiang, Guanghui Li, Yufeng Guo and Yongbin Yang *School of Minerals Processing & Bioengineering, Central South University, Changsha, Hunan 410083, China* 
