中低品位铝土矿添加铁酸钙的溶出规律及机制

Digesting rule and mechanism of middle and low grade bauxite with calcium ferrite

研究添加铁酸钙条件下铝硅比（A／S）为5．96的铝土矿的溶出规律对溶出赤泥进行X射线衍射、扫描电镜和能谱分析。结果表明：随铁酸钙添加量增多，溶出赤泥铝硅比和钠硅比均下降；随配矿量减少，溶出温度升高，溶出时间延长，溶出赤泥铝硅比降低；在温度为250℃，时间为60min，使用铁酸钙添加剂，得到的赤泥铝硅比为0．69，钠硅比（N／S）为0．21；赤泥中硅矿物以铁取代铝的水化石榴石为主，Fe2O3的饱和系数为0．73，Al2O3的饱和系数为0．22，SiO2饱和系数接近1，硅矿物组成改变是赤泥铝硅比和钠硅比降低的原因。

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 0.2 1. 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.