Red iron oxide pigment and production method thereof, and apparatus for producing red iron oxide pigment and use of apparatus

The invention relates to a red iron oxide pigment and a production method thereof, and an apparatus for producing the red iron oxide pigment and the use of the apparatus, specifically relates to an improved method for producing the red iron oxide pigment by use of the Penniman method using a nitrate (also called a nitrate method or a direct red method) and an apparatus for implementing the method, and also relates to use of the apparatus in producing the red iron oxide pigment by use of the Penniman method using the nitrate. The method for producing the red iron oxide pigment comprises at least the following steps: a) preparing the solution of ferrous nitrate (II) by virtue of the reaction of iron and nitric acid, thereby generating a first oxynitride-containing flow, and optionally separating any unreacted iron from the ferrous nitrate (II) solution prepared in such a manner later; b) preparing an aqueous hematite nuclear suspension by virtue of the reaction of the iron and the nitric acid, thereby generating a second oxynitride-containing flow, and optionally separating any unreacted iron from the aqueous hematite nuclear suspension prepared in such a manner later; c) preparing a hematite pigment suspension, and the like.