铝土矿预脱硅研究现状

Current Study Status of the Pre-desilicification for Bauxite

介绍了国内外铝土矿预脱硅的研究现状。目前铝土矿预脱硅的主要方法有化学方法、生物方法和物理方法。化学方法主要是使铝土矿中的铝硅酸盐矿物在高温条件下发生脱羟基反应。铝硅酸盐矿物晶体由于脱水而被破坏,形成无定形SiO2,这种活性较差的SiO2在低温条件下可溶于稀碱溶液中被脱除。生物方法则利用一些微生物的分泌物能够溶解铝硅酸盐矿物的特性,将铝土矿中的硅脱除。物理方法则是根据矿物粉碎难易程度的不同,以及铝硅酸盐矿物颗粒与铝土矿颗粒可浮性的差异,有选择性地将铝硅酸盐矿物从铝土矿中分离除去。对各种方法的优缺点进行了分析比较。

The current internal and external study status of the pre-desilicification for bauxite are reviewed. Currently, the main means of pre-desilicification for bauxite involve chemical methods, biological ways and physical methods. Chemical methods are used to make the aluminosilicates existing in bauxites react chemically in the high temperature with hydroxyl groups lost, which makes aluminosilicate crystals collapse due to desiccation, finally the amorphous SiO2 may be formed. This poorly active SiO2 can be dissolved in thin alkaline solution in relatively low temperature and sequentially removed from the system. The biological ways are to make use of characteristics that secretion secreted from some microorganisms can dissolve the aluminosilicates, and then the silicon may be removed from bauxite. While the physical methods are to separate aluminosilicates from bauxites with selectivity by means of flotation based on the difference of minerals comminution difficulty as well as the difference of floatabilities between aluminosilicate particles and bauxite particles. The advantages and disadvantages of every method have been compared with each another.