Preparation method of amorphous boron powder

Abstract

The invention relates to a preparation method of amorphous boron powder. The preparation method comprises the following steps: uniformly mixing a reducing agent, a boron-containing compound and an alkali metal compound-containing molten salt according to a mass ratio of 1.0:(1.2-3.6):(0.2-16.0), carrying out heat treatment in a protective atmosphere at 600-1300 DEG C for 0.5-8 h, dissolving the obtained product in water or an alkali solution at a temperature of room temperature to 250 DEG C, and performing filtering, washing and drying to obtain the amorphous boron powder. The preparation method has the characteristics of low production cost, environmental protection, easiness in industrial production, recycling of reaction byproducts and high boron recovery rate, and the prepared amorphous boron powder has the advantages of small particle size, narrow particle size distribution and high purity.

Description

technical field [0001] The invention belongs to the technical field of elemental boron materials. Specifically relates to a preparation method of amorphous boron powder. Background technique [0002] Amorphous boron powder has the advantages of large specific surface area and high combustion calorific value. It is mainly used in the synthesis of new metallurgical materials and boron-rich fuel in the aerospace field, and is also used as an initiator for airbags. [0003] At present, the preparation of boron powder mainly includes borane cracking method, boron halide hydrogen gas thermal reduction method, molten salt electrolysis method, metal thermal reduction method and so on. The borane cracking method is to use sodium hydride and boron trifluoride ether complex to undergo redox reaction to generate diborane, and then crack diborane at 300-900°C to prepare amorphous boron. Although this method can produce high-purity amorphous boron powder, diborane is gaseous and highly ...

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Problems solved by technology

Although this method can produce high-purity amorphous boron powder, diborane is gaseous and highly toxic at room temperature, making the production environment harsh, and the production cost is high, making it difficult to produce industrially.

Halide borohydrogen gas thermal reduction method, is to use pure H 2 Reduction of refined BBr 3 or BCl 3 Although the boron powder prepared by this method has high purity, the production cost is high, the boron recovery rate is low and the anticorrosion requirements for environmental protection facilities and equipment are very high, and industrial production cannot be realized

The molten salt electrolysis method is to prepare elemental boron by electrolyzing boron compounds under high temperature molten salt conditions. The most prominent problem in the preparation of boron powder by electrolysis is that the electrode material is difficult to solve, the yield is low and the energy consumption is high (Peng Cheng, Chen Song, Wu Yanke, et al. Preparation of boron powder by molten salt electrolysis. Rare Metals, 2010,34(2):264-270.)

The metallothermic reduction method uses magnesium powder to reduce boron oxide at high temperature to obtain coarse boron (Dou Zhihe, Zhang Tingan. Preparation of boron powder by self-propagating metallurgy. Chinese Journal of Nonferrous Metals, 2004, 14(12): 2137-2143. ), and then use HCl, NaOH and HF to prepare amorphous elemental boron powder. Although the metallothermic reduction method prepares boron powder with mature technology and large output, the product has low purity and uneven particle size distribution. A large amount of hydrochloric acid is required in the subsequent treatment process , the by-products produced have low added value, have a strong corrosion effect on equipment, and cause serious pollution

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