METHOD OF PRODUCING IRON-CONTAINING PIGMENTS Russian patent published in 2019 - IPC C09C1/22 C09C1/00 

FIELD: manufacturing technology.

SUBSTANCE: invention relates to production of inorganic pigments. Method of producing iron-containing pigments involves thermal treatment of feedstock. Initial raw material is prepared by mixing red mud of alumina production, bauxite, quick lime and carbonate soda Na₂CO₃. Thermal treatment of initial material is carried out in a rotating tubular furnace to obtain sodium-ferritic clinker, which is ground and divided into two parts. One part of clinker is directed for leaching, as a result of which a suspension of yellow pigment is obtained in mother solution. Cake obtained after filtering the suspension is washed with water and dried to obtain commercial yellow pigment. Second part of the clinker is mixed with bauxite; the obtained mixture is ground in a stream of a high-modulus alkali-aluminate solution. Obtained suspension is directed for leaching, as a result of which a red pigment suspension is obtained in the mother solution. Red filtering wet cake of the red pigment is washed with water. Then the cake is divided into two parts. One of the parts is delivered for repulping by water, then filtered and dried to produce commercial red pigment. Other part of cake is subjected to leaching in alkaline solution to obtain suspension of black pigment in mother solution. After wet filtration wet cake of black pigment is washed with hot water and dried to produce marketable black pigment.

EFFECT: invention widens the range of methods for producing iron-containing pigments with production of pigments of different color characteristics in a single process stream.

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