PRODUCTION OF RED IRON OXIDE PIGMENT Russian patent published in 2018 - IPC C01G49/06 C09C1/24 B01D53/56 B01D53/78 B01J8/00 B01J10/00 C02F1/58 C02F101/16 

FIELD: paint industry.

SUBSTANCE: invention can be used in paint and coatings industry. Method for producing red iron oxide pigments includes preparing an iron (ll) nitrate solution and a first nitrogen oxide-containing stream by reacting iron with nitric acid. Then an aqueous hematite nucleus suspension and a second stream, containing nitrogen oxide, are prepared by reacting iron with nitric acid. Suspension of hematite pigment is prepared by reacting an aqueous suspension of hematite kernels with an iron (II) nitrate solution and, at least, one alkaline precipitant in the presence of, at least, one oxygen-containing gas and/or by reacting an aqueous suspension of hematite kernels with an iron (II) nitrate solution, iron and, at least, one oxygen-containing gas. In this case the third nitrogen oxide-containing stream is produced. Hematite pigment is separated from the aqueous phase. Second nitrogen oxide-containing stream is oxidized producing an oxidized second nitrogen oxide-containing stream. Contacting the first nitrogen oxide-containing stream and/or the third nitrogen oxide-containing stream and/or the oxidized second nitrogen oxide-containing stream with an aqueous wash phase, thereby producing a prepurified gas stream and a wash phase, enriched with nitric acid. Removing dinitrogen monoxide and/or nitrous gases from the prepurified gas stream by heating to a temperature of 200 to 1,400 °C, producing a purified gas stream.

EFFECT: invention makes it possible to produce red iron-oxide pigments with a wide color spectrum and high yield more environmental friendly.

21 cl, 12 dwg