Patent ID: 9533891
Date: 2017-01-03
CPC Classifications: B01D,B03D,C01F,C02F,C22B

Claim:
1. A washing method of red mud that is produced when an alumina-containing ore having a goethite to hematite mass ratio of 60/40 (goethite/hematite) or more in the iron component thereof is heat-treated with an alkaline solution at a temperature of 110° C. to 160° C. to obtain an aluminate liquor, comprising: repeating a process, the process comprising mixing the red mud with a diluting fluid to obtain a suspension, adding a flocculant to the suspension, and settling and separating the red mud; wherein, in at least one of the process repetitions, a concentration of aluminum in the suspension is more than 95 g/L in terms of Al wherein, in at least one of the process repetitions, a concentration of aluminum in the suspension is 95 g/L or less in terms of Al