| abstract |
PURPOSE: To manufacture a plate iron oxide formed of a large iron oxide particle, showing excellent anticorrosive effect, with better efficiency and easily by adding boric acid or its salt to the reaction system in advance when subjecting the precipitate of ferric hydroxide or basic ferric salt obtained by contacting a ferric salt solution with an alkaline aqueous solution to a heat treatment. n CONSTITUTION: Boric acid or its salt, e.g., Na 2 B 4 O 7 , borax, etc., is added in advance in a porportion of 0.1 to 10 wt% per anhydrous ferric salt to the precipitate or mother liquor of Fe(OH) 3 or basic ferric salt obtained by bringing a ferric salt aqueous solution of ferric sulfate, etc., into contact with an alkaline aqueous solution or to the mother liquor during the precipitate formation period. In case the borate is a hydrate, it is converted into anhydrous compound for use. The alkaline aqueous solution as the mother liquor is then subjected to a heat treatment at 150 to 200°C, for example, in an autoclave to synthesize a large particle plate iron oxide (MIO) whose particle size in the direction of plate amounts to 30 to 100 microns. n COPYRIGHT: (C)1979,JPO&Japio |