PRODUCTION OF GRANULAR MAGNETITE PARTICULATE POWDER

摘要

PURPOSE:To industrially produce the granular magnetite particulate powder having <0.1mum particle size and suitable as material of magnetic ink and magnetic toner and having uniform particle size. CONSTITUTION:Alkaline suspension of >= pH9 contg. hydrated ferric oxide particles or ferric oxide particles and ferrous hydroxide having 50-200m<2>/g specific surface area is heated at >=40 deg.C, and the granular magnetic particulate having <0.1mum particle size is obtained.