摘要 |
PURPOSE:To prepare high quality iron oxide having low Si content, stably, by contacting the pickling waste solution of steel acidified with hydrochloric acid with silica gel, and calcining or crystallizing the filtrate. CONSTITUTION:The pickling waste liquid of steel is transferred from the waste liquid tank 2 to the mixing tank 4, charged with powdery silica gel from the silica gel storage bin 5, and stirred. The supernatant liquid of the waste is transferred to the precipitation tank 8, and then to the ultrafiltration module 11 via a preliminary filtration tank 10. The filtrate is stored in the filtrate tank 13, and sent to the calcination furnace or crystallizing apparatus at need to obtain iron oxide. High quality iron oxide having low Si content and suitable as a raw material of ferrite can be prepared by this process. |