PROCESS FOR THE PREPARATION OF BRIGHT, COLOR-PURE IRON OXIDE RED PIGMENTS

摘要

PROCESS FOR THE PREPARATION OF BRIGHT COLOR-PURE IRON OXIDE RED PIGMENTS of The Disclosure A bright, color-pure iron oxide red pigment is produced by an improved process by precipitation of iron(II) salts in aqueous solution with an alkaline precipitating agent, oxidation at temperatures of from 20.degree.C to 100.degree.C and annealing of the resulting precipitation product under air to form iron oxide reg pigments, wherein the improvement comprises before adding the alkaline precipitating agent, the iron(III) content of the aqueous solution is adjusted to 1 to 15 mol %, based on the total iron content of the iron salt solution.