METHOD OF OBTAINING IRON OXIDE PIGMENTS Russian patent published in 2018 - IPC C09C1/24 C09C3/04 C01G49/02 C22B7/00 C22B1/06 C05C3/00 

FIELD: technological processes.

SUBSTANCE: invention can be used in the preparation of pigments for the coloring of plastics, concrete, ceramic tiles, faience, porcelain products. To obtain iron oxide pigments, pyrite cucumber is subjected to rolling with concentrated sulfuric acid. Pellets are subjected to sulphating firing at temperature of 250–300 °C and then ultrasound-intensified aqueous leaching. From a mixture of water-soluble sulfates, obtained as a result of aqueous leaching, metal copper is isolated by cementation on iron. Then ammonium water is added and the hydroxides of titanium, aluminum, and zinc are sequentially separated. Filtration separates the precipitate of iron hydroxide Fe(OH)₂ and subjected to thermal oxidation in an air current at a predetermined temperature in the range of 400 to 1,000 °C depending on the chosen color of iron oxide pigments. Filtrate after the separation of iron hydroxide is oxidized with air oxygen, intensifying the process by ultrasound. Obtained precipitate of the yellow pigment FeO (OH) is isolated by ultrasonic filtration and dried at a temperature of not more than 120 °C. Filtrates are combined to form a liquid fertilizer, or evaporated to produce a fertilizer in the form of anhydrous ammonium sulfate.

EFFECT: invention makes it possible to obtain iron oxide pigments of a wide color range from pyrite cinder, as well as fertilizer.

1 cl, 2 ex