Preparation method for iron oxide black

The invention provides a preparation method for iron oxide black, which belongs to the field of preparation of pigments. The preparation method comprises the following steps: (1) uniformly mixing a soluble ferrous salt with soluble alkali and carrying out kneading at 20 to 25 DEG C so as to complete a reaction; (2) adding a certain amount of water into a reacted product obtained in the step (1) so as to obtain slurry; (3) introducing oxygen-containing gas into the slurry prepared in the step (2) and carrying out an oxidation reaction under the conditions that a temperature is 20 to 60 DEG C and a pH value is 6.5 to 7.5; (4) heating the slurry having undergone the oxidation reaction in the step (3) to 60 to 90 DEG C, adding a certain amount of the soluble ferrous salt and soluble alkali into the slurry and carrying out an addition dehydration reaction; and (5) after completion of the reaction, carrying out filtering and drying a filter cake so as to obtain a finished iron oxide black product. The iron oxide black prepared by using the method has the advantages of a single crystal structure, a small particle size, high purity and strong tinting strength.