the subject matter of this invention relates to a process for deactivating the soluble metal cations contained in iron oxide pigments comprising : a . adding , while oxidizing , an alkalizing compound to an iron oxide pigment , a slurry until the ph of the pigment slurry is greater than 9 ; and b . separating the iron oxide pigment from the liquid phase of the slurry . the pigments can be used as colorants for substances ingested by man and animals , and they can also be used to stabilize plastics against ultraviolet degradation .