Patent ID: 8512590
Filing Date: 2013-08-20
Classification: C01G,C01P,C04B,H01F

Abstract:
1. A method for producing a sintered ferrite magnet having an M-type ferrite structure, comprising Ca, an R element that is at least one of rare earth elements and indispensably includes La, Ba, Fe and Co as indispensable metal elements, and having a composition represented by the following general formula: wherein (1−x−y), x, y, z, and n represent the contents of Ca, the R element, Ba and Co, and a molar ratio, meeting 0.3≦1−x−y≦0.65, 0.2≦x≦0.65, 0.001≦y≦0.2, 0.03≦z≦0.65, 4≦n≦7, and 1−x−y>y, said method comprising the steps of mixing a Ca compound, an R element compound, a Ba compound, an iron compound and a Co compound as starting materials for the composition; calcining the starting materials to obtain calcined bodies; pulverizing the calcined bodies to obtain a calcined powder; providing recycled materials having an M-type ferrite structure, comprising Ca, an R element that is at least one of rare earth elements and indispensably includes La, Ba, Fe and Co as indispensable metal elements, and having the same metal composition as the one represented by the above-mentioned general formula; pulverizing the recycled materials to obtain a recycled material powder; mixing the recycled material powder with the calcined powder to form a moldable material; molding the moldable material to obtain green bodies; and sintering the green bodies to obtain the sintered ferrite magnet; wherein the mixing ratio of the recycled material powder to the calcined powder of the moldable material is 5 to 95 parts by mass to 95 to 5 parts by mass, and wherein the recycled materials comprise at least one of failed green bodies, failed sintered bodies and dust generated in the machining of the sintered bodies.