PRODUCTION OF NEEDLEELIKE GOETHITE

摘要

PURPOSE:To produce needle-like goethite of a small particle size by regulating the ratio of anion such as sulfate ion or the like to ferrous ion in an aq. soln. of ferrous sulfate or the like to below 1 and oxidizing the regulated soln. at a predetermined pH and temp. to considerably shorten the reaction time. CONSTITUTION:FeSO4 7H2O is adjusted to pH>=11 with a alkali such as NaOH, and the ratio of sulfate ion to ferrous ion is regulated to below 1. The regulated FeSO4 7H2O is then oxidized by blowing air or the like. The resulting needle-like goethite is small in particle size, and gamma-Fe2O3 made of the goethite is also small in particle size and exhibits more superior magnetic characteristics than those of a conventional product.