Method for industrially preparing silane

Abstract

The invention discloses a method for industrially preparing silane. The silane is prepared by reaction between citric acid and magnesium silicide serving as raw materials. The method comprises the following steps: continuously adding citric acid and magnesium silicide at a molar ratio of 4:3 into a reaction kettle while isolating air in an aqueous phase condition; mixing and reacting at normal temperature; continuously collecting the generated coarse silane gas at a condenser outlet at the top of the reaction kettle; processing with a conventional technology to obtain refined silane; compressing the silane with a metal membrane compressor; and liquefying and bottling to obtain the finished product of silane, wherein the purity of the finished product of silane is over 5N (99.99%). The invention has the advantages that no pollutant or waste needs to be disposed in the whole production process, and high-purity magnesium citrate can be obtained while the silane is produced. Through the method in the invention, 9 tons of anhydrous magnesium citrate can be produced during the production of 1 ton of silane, namely that the cost of raw materials is not increased for producing magnesium citrate. Moreover, the preparation of silane and magnesium citrate from citric acid and magnesium silicide is neither reported domestically nor applied to industrial production.

Description

technical field [0001] The invention relates to a synthesis method of chemical raw materials, in particular to a method for industrialized production of silane. Background technique [0002] Silane is an important chemical raw material, which can be used to manufacture electronic-grade polysilicon, amorphous silicon thin-film batteries, silicon wafer epitaxy, coated glass, nano-silicon materials, etc. At present, only a few companies such as the United States and Japan have realized industrialization. The UCC method (using trichlorohydrosilane and hydrogen as raw materials) and the MeMc method (using silicon tetrafluoride and sodium aluminum hydride as raw materials) used in the United States to produce silane are suitable for the construction (single factory) of silane plants with an annual output of more than 1,000 tons. The investment is huge (several billions to tens of billions of RMB are required), and the technology, equipment and investment threshold are extremely hi...

AI Technical Summary

Problems solved by technology

The UCC method (using trichlorohydrosilane and hydrogen as raw materials) and the MeMc method (using silicon tetrafluoride and sodium aluminum hydride as raw materials) used in the United States to produce silane are suitable for the construction (single factory) of silane plants with an annual output of more than 1,000 tons. The investment is huge (several billions to tens of billions of RMB are required), and the technology, equipment and investment threshold are extremely high; Japan uses the Komatsu method (using ammonium chloride and magnesium silicide as raw materials) to produce silane, although the investment is small, but the production scale Small, only suitable for the construction of small-scale (about 20-50 tons) silane factories, and the crystallization of the by-product 6-ammonium magnesium chloride is easy to block the reactor, ammonia recovery is difficult, and the production cost is high

In the 1970s, my country introduced Japan's Komatsu method technology to produce silane after successive failures, and has not yet realized industrial production.