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赤泥是从铝土矿中提取氧化铝的过程中产生的工业废渣。分析了拜耳法赤泥的粒径分布,以及主要化学组成和矿物组成在不同粒径赤泥中的变化规律。在此基础上,提出先将赤泥粒径分级预处理,然后根据粗细粒径赤泥的差异分别进行回收利用的思路。研究结果表明,赤泥中粒径大于0.075 mm的粗颗粒以铁、硅、钙为主,实践证明可以通过磁选或重选工艺直接从中回收铁矿;赤泥中粒径小于0.075 mm的细颗粒占赤泥总质量的74.31%,其铝硅比(A/S)由原来的0.81提高到1.08,初步实验证明可以利用还原焙烧-溶出-磁选工艺联合回收铁铝元素。分析认为,该预处理过程具有较好的环境效益。
Red mud is an industrial waste produced during the extraction of alumina from bauxite. The particle size distribution of Bayer red mud was analyzed, and the variation of main chemical composition and mineral composition in red mud of different particle sizes was analyzed. On this basis, we propose that the particle size of red mud should be graded pretreatment first, and then the idea of recycling according to the difference of red and white mud of coarse and fine particle size should be taken. The results show that the coarse particles with a diameter of more than 0.075 mm in the red mud mainly consist of iron, silicon and calcium. It has been proved that the iron ore can be directly recovered from the slurry through magnetic separation or re-selection. The diameter of the red mud is less than 0.075 mm The particles accounted for 74.31% of the total mass of the red mud, and its A / S ratio increased from 0.81 to 1.08. Preliminary experiments show that the reduction of roasting-leaching-magnetic separation can be combined to recover Fe and Al. Analysis, the pretreatment process has good environmental benefits.