Thann Et Mulhouse, Corp.

Jean-Marie C Trautmann

Daniel A Hoffner

Pigmentary red iron oxide particulates essentially devoid of manganese impurities and ranging in shade from the orange-reds to the purplish reds, are conveniently prepared by (1) calcining, even at higher temperatures, an intimate admixture of (i) a ferrous sulfate hydrate containing contaminating amounts of manganese values, e.g., a by-product stream of ferrous sulfate, and (ii) an alkali metal compound, said admixture comprising from 0.08 to 1 gram-atom of alkali metal per mole of Fe.sub.2 O.sub.3 produced, (2) washing the calcined admixture with water to remove essentially all water-soluble manganese values therefrom, and advantageously (3) drying and (4) grinding the calcined and washed admixture.

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Thann, France

Jean-Marie C Trautmann