PROCESS FOR PULVERIZING MAGNETIC POWDER

PROBLEM TO BE SOLVED: To solve the problems upon pulverizing rare earth magnetic powders of 110 μm into fine grains of about 3 μm using a jet mill, such as extension of processing time. SOLUTION: Into a first jet mill 11, 3 kg raw material powders are introduced and subjected to a grain-refining treatment (a first pulverization step). The obtained fine granules of 8 μm are divided into two masses, each weighing 1.5 kg, which are separately introduced into a second jet mill A 12A and a second jet mill B 12B and subjected to a grain-refining treatment (a second pulverization step). Compared to a conventional process employing only one pulverization step, the process employing two pulverization steps should result in a threefold increase in production. COPYRIGHT: (C)2004,JPO