Method for preparing magnesium silicide and device

Abstract

The invention discloses a preparation method of magnesium silicide and a device thereof. In the preparation method, equivalently mixed magnesium powder and silicon powder are used as raw materials, continuously fed into a vertical cylindrical reactor from the top under vacuum or gas protection, and continuously stirred, so as to allow uniform and complete reaction and prevent excessive heat generation from the reaction and magnesium vapor escape. The inventive device is mainly the vertical cylindrical reactor instead of a horizontal reactor, and a reducer at the top of the rector is used for driving a spiral stirrer to stir the raw materials; a heater is arranged on the upper part of the outer wall of the reactor for heating, a cooling water jacket is arranged on the lower part of the reactor for cooling, a scraper and a perforated plate are arranged at the bottom of the reactor for pulverizing the generated magnesium silicide from the reaction, the upper part of the reactor is connected with a feeding device, and the lower part of the reactor is connected with a discharge device. After the reaction is completed, the continuous product is made into magnesium silicide powder with fine particle size, uniform composition and equivalent weight through pulverization by the scraper and the perforated plate. The inventive preparation method can realize continuous production of magnesium silicide, improve conversion rate of raw materials, reduce magnesium consumption, and reduce energy consumption.

Description

technical field [0001] The invention relates to a preparation method and device of magnesium silicide. Background technique [0002] Magnesium silicide is an important industrial raw material, which is widely used in the preparation of silane gas, polysilicon, amorphous silicon film, ceramic materials and silicon-containing nano-powder, etc. Advanced ceramics are playing an increasingly important role. The development of high-efficiency, high-quality and low-energy industrial synthesis technology is the development direction of magnesium silicide technology. [0003] The traditional synthesis method of magnesium silicide is to mix silicon powder and magnesium powder in proportion, and heat them to about 500-650°C in hydrogen atmosphere or vacuum to make them react to produce magnesium silicide powder. The reaction formula is: [0004] 2Mg+Si→Mg 2 Si+77.4kJ [0005] Because the reaction of synthesizing magnesium silicide is an exothermic reaction, when synthesizing magnes...

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Problems solved by technology

However, since the above two schemes basically use horizontal reaction tubes, there is no material filling on the upper part of the reaction tubes, which will cause the leakage of magnesium vapor and cause the loss of magnesium.

In the ratio of materials in this type of horizontal reactor, magnesium must be in excess of 3-10%, which not only causes a waste of magnesium, but also crystallizes the evaporated magnesium on the surface of the inner parts of the reaction tube, which will hinder the normal operation of the mechanism.

Therefore, the yield and product quality of the plant are limited

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