Process for preparing precipitated red iron oxides - Cities Service .Mar 17, 1981 . A precipitated red iron oxide, having high crystallinity, low acicularity, unifrom . 3946103, Production of precipitated red iron (III) oxide pigment.red iron oxide production,2 Inorganic pigments using the Laux process - Bayferroxlaunched in Krefeld. Since then, iron oxide production at the Krefeld plant has un- . In the Laux process, all three basic iron oxide colors - red, yel- low and black.