Production method of needle-like γ-FeOOH

摘要

PURPOSE:To produce a needle shaped gamma-FeOOH useful as a precursor of a magnetic powder suitable for magnetic recording with industrial advantage. CONSTITUTION:In a reaction for growing a gamma-FeOOH nucleus crystal suspended in a ferrous salt solution by oxidizing it while neutralizing the suspension with an alkali, a phosphorous compound is added to the reactional system under a condition of Fe++ in reactional system/whole Fe of =0.15 before completion of the reaction.