Activation of Coal Waste and Extraction of Al₂O₃

The raw kaolinite-coal-waste is chemically stable and difficult to extract alumina straightly without chemical activation.In this paper,the activation of kaolinite-coal-waste and extraction of alumina is systematically studied.The results show that the reactivity of kaolinite-coal-waste and the extraction ratio of alumina are enhanced remarkably from 7.24% to 75.31% after calcination for 45min at 680℃.At suitable conditions of HCl∶kaolinite = 5∶1,reaction time of 90min and HCl concentration of 20 wt.%,the extraction ratio of alumina from the calcined coal waste is 83.67% that is a relatively high extraction ratio.It is promising to extract alumina from the kaolinite-coal-waste via the high-temperature calcination and suitable acid-treatment process.