It is the first time to determine whether gallium in fly ash was dissolved out with aluminum and study how to separate gallium from aluminum and recover it, tracking and analyzing the gallium in the digested mother liquor from a power plant fly ash extracting Al2O3 by soda-lime sintering process. Carbon dioxide decomposition was performed to the digested mother liquor, exploring the influences on separation of gallium from aluminum from carbon dioxide decomposition time, flow rate, and carbon dioxide decomposition temperature. The results show that when feeding CO2 into the solution, aluminum was firstly dissolved out as the form of Al(OH)3 and then gallium. When carbon dioxide decomposition time, flow velocity and carbon dioxide decomposition temperature were 30min, 100mL/(min • L) and 40°C, respectively, the ratio of aluminum to gallium was from 1028 down to 200. Under this condition, most of aluminum was dissolved out from the solution but gallium was still in it, thus successfully separating gallium from aluminum and leading to a better condition of subsequent process of extracting gallium.
Detoxification Mechanism of Molten Fly Ash in Sintering Process