The invention discloses a method for comprehensively utilizing
red mud, comprising the following steps: chloridizing
roasting, namely
roasting the mixture of the
red mud,
coal and
calcium chloride;
cinder treatment, namely obtaining magnetic iron
slag and non-magnetic
slag after
magnetic separation is carried out to levigated
cinder, and then separating the magnetic iron
slag and non-magnetic slag; adding calcined soda or
oxalic acid after levigation liquid and
wash water are rich in
mischmetal due to cyclic use, and then precipitating
mischmetal slag; treatment of dry dust and circulation liquid, namely, after
dry powder for
roasting dust collection is collected, mixing the
dry powder with scouring water which is used for
tail gas circulation and then leaching soluble ScCl3 and GaCl3; after filter pressing, precipitating
scandium by adding
oxalic acid crystal in filtrate; carrying out filter pressing again, precipitating
gallium and Ti(OH)4 by adding
ammonia into the filtrate, dissolving obtained
gallium-
titanium slag with acid and then using P2O4 extractant to extract the
gallium; and using extractant to extract the
scandium after
scandium precipitate is dissolved by acid, carrying out
precipitation again by adopting back-extraction acid dissolving, and obtaining Sc2O3 by means of roasting. The method can realize
recovery of valuable metals from the
red mud, and secondary residual slag is totally used for
building material production; and the method has environment protection effects and
economic benefits, plays an important role in the development of recycling economy and is applicable to enterprises generating red mud.