Abstract: A purified solution containing iron chloride and manganese chloride, having a phosphorus content not higher than about 0.007 wt. % with respect to the total content of iron and manganese. The method for producing the purified solution comprises the steps of dissolving manganese containing raw material in hydrochloric solution; oxidizing the solution; adjusting the pH of the solution to 2.5.about.4.5 to form insolubles; and separating the insolubles from the solution. This solution can be utilized to produce a mixed powder of an iron oxide and a manganese oxide. The mixed powder is useful for producing a high-quality soft ferrite.

Abstract: A method for producing a powdered iron oxide comprises the steps of adjusting the pH of a crude iron chloride solution to 2.5-4.5; reducing the P content of the solution by mechanical stirring or air bubbling and filtering; and oxidizing the solution into a powdered iron oxide having a maximum P content of 0.005 wt. %. The P content of the solution may also be reduced by ultrafilter treatment. The soft ferrite made by using the powdered iron oxide by this process shows excellent magnetic properties.