Efficient Extraction of SiO2 and Al2O3 from Coal Gangue by Means of Acidic Leaching

Coal gangue is mainly composed of SiO2, Al2O3 and other components. It is a huge reserve of aluminum and silicon resources. The coal gangue stockpiles in China is more than 5 billion tons at present, of which contain Al2O3 more than 1 billion tons, SiO2 more than 2.5 billion tons. It will make supplement for the lack of bauxite resources in China to some extent by extracting Al2O3 with appropriate methods. In the same time, it will meet the strong demand of national economic growth for aluminum and silicon requirement, and to ensure the safety of national mineral resources. Research for extraction of Al2O3, SiO2 by acid leaching way was carried out in this paper. The influence of acid material ratio, leaching temperature, and leaching time on Al2O3, SiO2 extraction was dealt with in detail. Al2O3, SiO2 in accordance with China national products standard were obtained by optimization of the leaching conditions and parameters.