(1. 东北大学 材料与冶金学院，沈阳 110004 ；
2. 中国铝业股份有限公司 郑州研究院，郑州 450041)
（1. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China;
2. Zhengzhou Research Institute, Aluminum Corporation of China Limited, Zhengzhou 450041, China）
Abstract:The digesting rule of diasporic bauxite with A/S of 5.96 was studied by adding calcium ferrite. With increasing addition of calcium ferrite, A/S and N/S in the red mud are reduced. Under the conditions of higher digestion temperature and longer time, A/S in the red mud is reduced with lower bauxite addition. Under the condition of 250 ℃, 60 min and adding calcium ferrite, large scale experiments have been done, which results in that A/S in the red mud is 0.69, N/S is 0.21. The main Si-mineral of red mud is ferrite hydro-garnet through analysis of X-ray diffraction and SEM. The coefficient of SiO2 approaches 1, Al2O3 is 0.22, Fe2O3 is 0.73 in ferrite hydro-garnet. It is because the structure of Si-mineral is changed that A/S and N/S in the red mud is greatly reduced.
Key words: bauxite; calcium ferrite; Bayer process; digestion
