OBTAINING RED IRON OXIDE PIGMENTS Russian patent published in 2019 - IPC C01G49/06 C09C1/24 B82B3/00 B82Y30/00 

FIELD: construction.

SUBSTANCE: invention can be used in production of ceramic construction materials, polymers, paints, varnishes and paper. Method of producing hematite pigments involves reacting iron with an aqueous suspension of hematite nuclei and a solution of iron (II) nitrate in the presence of at least one oxygen-containing gas at temperatures of 70 to 99 °C. Hematite nuclei are characterized by particle size of 100 nm or less and measured according to DIN 66131 specific BET surface area of 40 to 150 m²/g. Suspension of hematite nucleation nuclei is added to iron. Before adding, after addition or simultaneously with addition of a suspension of hematite nucleation nuclei, a solution of iron nitrate (II) is added to the mixture so that after 80 % to 100 % of the entire reaction period the concentration of iron (II) nitrate in the liquid phase in terms of anhydrous Fe(NO₃)₂ ranges from 0.1 to 25 g/l.

EFFECT: invention increases output of red iron oxide pigments with a wide colour spectrum, reduces energy losses and the amount of nitrogen oxides released into the environment.

8 cl, 1 dwg, 4 tbl, 12 ex