从煤系高岭岩中提取氧化铝

Leaching aluminum oxide from kaolinite in coal measures by lime sintering

研究以煤系高岭岩为原料,经焙烧活化、预脱硅处理、碱石灰烧结提取氧化铝。着重考察了煤系高岭岩的焙烧活化、预脱硅处理等过程的工艺条件,比较了预脱硅处理后精矿的氧化铝提取率与煤系高岭岩直接采用碱石灰烧结的氧化铝提取率。研究得出:煤系高岭岩经1000℃、30min焙烧活化后,以15%NaOH溶液对其进行脱硅处理,选用适当的助剂,可在液固比为5ml/g、90℃、90min的条件下获得70%左右的脱硅率。使高岭岩的Al/Si由0.96提高到4.88,满足了碱石灰烧结法对原料Al/Si的要求。同样采用碱石灰烧结法提取氧化铝,在1150℃下烧结60min后,饱和生料的Al2O3提取率由煤系高岭岩的45%提高到精矿的89%。预脱硅处理将高岭岩的氧化铝提取率提高了近一倍。

The process of leaching aluminum oxide from kaolinite in coal measures by treatments of roasting, desilicon , lime sintering is researched, in which the conditions of roasting and desilicon are studied in detail, and the leaching rates of aluminum oxide of the residue and kaolinite in coal measures are compared as well. The results are as follows: having undergone the roasting of 1000℃, 30 min and the desilicon of 15% NaOH,90 ℃,90 min with a proper additive, the kaolinite in coal's desilicon rate is up to about 70%, and its Al/SI ratio can be heightened from 0.96 to 4.88,which enables the residue to be used as the material of preparing aluminum oxide by lime sintering. After the sintering of 1150℃,60 min, the leaching rate of aluminum oxide of the residue is elevated to 89% from that of 45% in the kaolinite in coal. The result proves that the pre-desilicon process nearly doubles the leaching rate.