Production of tri-iron tetroxide pigment

Abstract

Abstract PURPOSE:To provide a tri-iron tetroxide pigment having excellent particle size distribution and improved oxidation stability, by adding a hydroxosilicate salt soln. or a hydroxoaluminic acid soln. in the air oxidation of an aq. soln. of ferrous hydroxide. CONSTITUTION:An aq. soln. of an alkali is added to a ferrous salt soln. (e.g. ferrous sulfate soln.) to form ferrous hydroxide. Air oxidation is then carried out. When the ratio of ferrous ion to ferric ion in the reaction mixture is 10-1, a hydroxosilicic acid soln. or a hydroxoaluminic acid soln. is added thereto in such a quantity as to give 0.5-3wt% (in terms of Si/Fe3O4 or Al/Fe3O4) based on the quantity of iron in the reaction mixture. The air oxidation is continued to form tri-iron tetroxide particle which is then washed with water to remove salts. The resulting particle is dried at 105-110 deg.C to obtain the desired tri-iron tetroxide pigment.

Inventors

• 👤 Akio Sugiyama
• 👤 杉山　明夫

Bibliographic Details