| 摘要 |
PURPOSE:To prevent the formation of the immobile part of powder and to accelerate reaction by expanding the gas ejection port of a gas diffusion plate of a fluidized layer type apparatus for producing silicon nitride powder by silica reduction method to a funnel shape in the upper part on the synthesizing chamber side. CONSTITUTION:The gas diffusion plate 6 having the gas ejection ports 9 is provided in the lower part of the synthesizing chamber 8. Many pieces of the ports 9 are spaced from each other and are disposed over the entire part of the plate 6 and the upper parts 13 thereof expand like a funnel. The top edges 14 thereof are contiguous to each other and the upper parts 13 expand linearly. The angle theta of inclination thereof has an angle above the angle of repose of the powder 12. The powder (e.g.: silica granules, etc.) is put into the chamber 8 constituted in such a manner and gas (e.g.: gaseous N2, etc.) is blown through the ports 9 from below, then the powder 12 is fluidized by the gas and reacts at the same instant. There are substantially no surface parts where the powder 12 forms the immobile part atop 11 the plate 6 and therefore, the powder 12 and the gas contact satisfactorily with each other and make the reaction uniform. |
