초록 ▼

A process for the production of a black iron oxide pigment from Fe.sub.2 O.sub.3 hematite iron oxide which may be an impure oxide produced by the "Ruthner" process or by other means, or which may be a mineral hematite. The process may be used to upgrade poor quality synthetic or natural hematite, or

A process for the production of a black iron oxide pigment from Fe.sub.2 O.sub.3 hematite iron oxide which may be an impure oxide produced by the "Ruthner" process or by other means, or which may be a mineral hematite. The process may be used to upgrade poor quality synthetic or natural hematite, or to improve their performance as red pigments, by conversion to black pigment with subsequent oxidation of the magnetite so produced back to hematite. The process uses a low temperature aqueous slurry reaction in which the hematite is contacted with a soluble source of Fe(II) ions in the presence of a soluble source of Fe(III) ions in an aqueous alkaline medium to convert the same to Fe.sub.3 O.sub.4.

대표청구항 ▼

[ What is claimed is:] [1.]1. A process for production of black iron oxide (Fe.sub.3 O.sub.4) pigment from iron oxide having a hematite crystal structure comprising contacting a hematite with a soluble source of Fe(II) ions in the presence of a soluble source of Fe(III) ions in an aqueous alkaline m

[ What is claimed is:] [1.]1. A process for production of black iron oxide (Fe.sub.3 O.sub.4) pigment from iron oxide having a hematite crystal structure comprising contacting a hematite with a soluble source of Fe(II) ions in the presence of a soluble source of Fe(III) ions in an aqueous alkaline medium to convert said hematite to Fe.sub.3 O.sub.4.