低品位铝土矿脱硅研究

Research on desilication of low grade bauxite

采用两步氟化法处理低品位铝土矿,部分低品位铝土矿经氟化氢常温脱硅产生氟化铝,再加低品位铝土矿原矿与生成的不稳定氟化铝高温分解脱硅除氟制取高品位铝土矿。研究了铝土矿颗粒粒度、流化温度、流化时间对氟化氢脱硅的影响;又系统研究了焙烧温度、混合反应比等因素对脱硅除氟的影响。实验结果表明最优工艺条件为:控制矿石粒度为100目,在常温下通入氟化氢气体,通气时间1h,反应30min;控制氟化铝与铝土矿质量比1∶1.2,焙烧温度1000℃,焙烧时间3h。在此条件下,能达到最好的效果,制得的高品位铝土矿铝利用率达85%,其铝硅比达19,满足相关化工产品的标准。

The two - step fluorination process was used to dispose the low grade bauxite, part of the low grade bauxite was desiliconized by hydrogen fluor- ide at room temperature and produced small amount of unstable aluminum fluoride, which was then pyrolysed, desiliconized and defluorinated with the ex- tra low grade bauxite to produce high grade bauxite. The influence of particle size, fluidized temperature and fluidized time on desilication by hydrogen fluoride was systematically studied, and the influence of temperature and ratio of raw material on the desilication and defluorination was systematically studied in this paper. The experimental results showed that the optimized conditions of reaction were as follows： ore particle size was 100 mesh, hydrogen fluoride was inlet in the room temperature for 1 h and react 30rain; the ratio of unstable aluminum fluoride to bauxite wasl ： 1.2, the calcinations tempera- ture was 1000℃, the reaction lasted for 3h. Under those conditions, two -step fluorination process can achieve the best effect, the aluminum utilization rate of the high grade bauxite can be up more than 85%, and its alumina - silica ratio reached 19, meeting the standard requirements of related chemical products.