The invention discloses a method for preparing
pigment-grade
chromium oxide green. The method comprises the steps of taking reducing gas as a
reducing agent, allowing
chromic salt to react with the reducing gas for 0.5 to 3 hours at a temperature between 300 and 800 DEG C, cooling, using water to wash and hydrolyzing a reaction mixture, mixing the reaction mixture with additives at a temperature between 700 and 1,300 DEG C, activating and
sintering the reaction mixture and the additives for 0.5 to 3 hours, washing,
drying and grading the sintered material to obtain the
pigment-grade
chromium oxide green, wherein the
chromic salt is chromate or bichromate; the reducing gas is
hydrogen,
natural gas,
ammonia gas,
coal gas or a mixture thereof; and the additives are
silicon compounds,
titanium compounds,
boron compounds,
phosphorus compounds, aluminum compounds,
barium compounds,
zinc compounds and other compounds, such as SiO2, K2SiO3, Na2SiO3, TiO2, K2TiO3, B2O3, H2BO3, H3PO4, P2O3, Al2O3, Al(OH)3, Al2(SO4)3, AlCl3, Al(NO3)3, BaO, Ba(OH)2, BaSO4, BaCl2, Ba(NO3)2, ZnO, ZnCl2, ZnSO4, Zn(NO)3, Sb2O3 and other substances.