Experimental study of extracting alumina from coal fly ash using fluidized beds at high temperature

Experiments are conducted to investigate the process of alumina extraction from coal fly ash generated by coal-fired power plants located in the northern parts of China. Coal ash and ammonium sulfate are mixed and granulated under the effect of binder material. The high temperature fluidized bed reactor is used for the first time to recover the alumina in solid state. The whole process is simplified and operated continuously to make sure its feasibility for the industry. The effect of operating parameters, temperature, reaction time and reactants ratio on efficiency is discussed. The experimental results show that this method has the potential to recover alumina efficiently. And results also show that 60% reaction time is saved when compared with the acid process. The maximum of extracting efficiency reaches nearly 90% at high temperature under laboratory conditions.