Preparation of spherical amorphous boron particles via a green silicothermic reduction method

Abstract

Spherical amorphous boron with an average particle size of 380 nm have been successfully prepared by a novel silicothermic reduction method using silicon, alkali borate and silicate as raw materials. The low-viscosity R2O-B2O3-SiO2 melt that exist in the above reaction system could be used to facilitate the silicothermic reduction and absorption of silica, a water-insoluble by-product formed in conventional silicothermic reduction. In contrast to silica, the by-product of improved silicothermic reduction is alkali silicate which could be separate easily by washing. Besides, the alkali silicate aqueous solution is an important recyclable industrial material. The results reveal that this is a simple and environment-friendly way to prepare sub-micron amorphous boron particles with intact sphericity.