| 摘要 |
PURPOSE:To improve saturation magnetization, etc., by adding CO2 to a water- dispersion slurry containing needle-like iron oxyhydroxide or iron oxide, water- soluble barium compd. and alkali hydroxide, controlling the slurry to specified pH, then adding phosphoric acid thereinto, and then filtering and calcining. CONSTITUTION:(A) 5-7g/l of needle-like iron oxyhydroxide or iron oxide having the average major axial length of 0.1-1.0mum and the average minor axial length, of 0.01-0.1mum and (B) water-soluble barium compd. are dispersed in (C) water, to which (D) alkali hydroxide is added to obtain a water-dispersion slurry of >=pH8. Then, to this slurry, (E) carbonic acid gas and/or carbonate are added to control the pH to 8-12 and to coat the surface of the (A) component with (B) component. Then, (F) phosphoric acid is added thereto by 0.1-1.5mol% to Fe of the (A) component, and the slurry is filtered, washed with water, dried and calcined at 700-1000 deg.C to obtain the magnetic powder of this purpose. |
