生产氧化铝用的铝土矿,一般含有铁的氧化物、硫化物和硫酸盐矿物。当用铝酸钠溶液高压浸出时,铁的硫化物便部分地分解成硫化钠和硫化亚铁,并同时进入溶液。分解过程中铁进入氢氧化铝,从而使氧化铝质量变坏。除铁净化溶液所沿用的方法,如通过纸浆和纤维质滤层过滤、向溶液中添加铁的凝聚剂或其它沉淀剂等,对净化铝酸钠溶液均未取得好效果。对拜耳法铝酸 Bauxite for the production of alumina generally contains iron oxides, sulphides and sulphate minerals. When leached with sodium aluminate solution at high pressure, the iron sulfide partially decomposes into sodium sulfide and ferrous sulfide and simultaneously enters the solution. The decomposition of iron into the aluminum hydroxide, so that the deterioration of the quality of alumina. In addition to iron purification solution used in methods such as filtration through the pulp and fibrous filter layer to the solution of iron coagulant or other precipitating agent added to the purification of sodium aluminate solution did not get good results. To Bayer process aluminate