Abstract: An atomization roasting furnace for producing ferrite raw material powder includes an elongated roasting furnace body with a center burner located at the top end thereof. At least three liquid spray nozzles are located in an expansion slope portion below the center burner circumferentially with respect to the center burner. A quencher, located below the elongated roasting furnace body, has a top end connected to a bottom end of the elongated roasting furnace body. Quencher nozzles are located adjacent the top end of the quencher.

Abstract: This invention provides an atomization roasting method which can easily obtain a soft ferrite sintered body, for example, a sintered body having a crystal particle size of not greater than 2 .mu.m, by using as a raw material an ultra-fine powder having a mean particle size of not greater than 0.1 .mu.m obtained by atomization roasting and which can obtain a soft ferrite raw material powder subjected to an oxidation reaction, having an extremely small residual chlorine content, and having and extremely small deviation of high vapor pressure components such as zinc between the atomized raw material solution and the oxide as the product and which can economically produce a soft ferrite core having an excellent power loss characteristic in a high frequency range, particularly in a MHz range, and is extremely effective for reducing the size of a high frequency transformer.