METHOD FOR COMPLEX PROCESSING OF RED MUD Russian patent published in 2022 - IPC C22B3/10 C22B7/00 C22B21/00 C22B59/00 

FIELD: alumina production.

SUBSTANCE: invention relates to the extraction of iron, aluminum, titanium, silicon and scandium from red mud of alumina production. The red mud is dried, fired at a temperature of 1200-1400°C and cooled in a neutral atmosphere. It is ground, separated into magnetic and non-magnetic fractions by wet magnetic separation, the non-magnetic fraction is leached with a hydrochloric acid solution under autoclave conditions, the pulp is filtered to obtain a chloride solution and a silicon-titanium residue. Amorphous silica from the silicon-titanium residue is obtained by leaching with a sodium hydroxide solution followed by acid precipitation. The aluminum chloride hexahydrate is salted out from the chloride solution with concentrated sulfuric acid or a mixture of hydrochloric acid vapors with an inert gas. The precipitate of aluminum chloride hexahydrate and the saturated chloride solution are separated. The precipitate is calcined to obtain alumina. Exhaust gases are sent to saturation of the recycled hydrochloric acid solution. The chloride solution is extracted with a mixture of D2EGFK, TBP and kerosene at a ratio of B:O=3:1 to obtain a raffinate and a loaded organic phase, from which scandium is re-extracted. The titanium-silicon residue is leached with a NaOH solution with T:W=1:24. The undissolved solid residue is dried to obtain a titanium concentrate.

EFFECT: method allows complex processing of red mud without the formation of solid waste, increasing the extraction of aluminum and scandium into the aluminate solution, increasing the extraction of titanium and silicon into the solid residue of acid leaching and obtaining commercial products - iron concentrate, alumina, amorphous silica, scandium and titanium concentrate.

1 cl, 7 dwg, 6 tbl, 1 ex