金属镁热还原法制备非晶硼粉的研究

传统的金属镁热还原法制取的硼粉纯度低，含有大量的镁、氧等杂质。针对此问题，本文探讨了Ｂ_２Ｏ_３粉镁热还原法制取硼粉时物料配比、反应物粒度等因素对产品纯度的影响并分析了原因；还考查了反应保温时间对产品结构的影响，发现反应结束后物料应迅速冷却，否则，随保温时间延长会生成难溶化合物Ｍｇ_３（ＢＯ_３）_２，导致硼粉含镁、氧增加。对于反应中生成难溶的Ｂ_６Ｏ、Ｂ_７Ｏ及ＭｇＢ_ｘ化合物，提出采用氧化热分解法降氧除镁，研究了其工艺条件和效果，所得纯硼粉含Ｂ＞９５％、Ｍｇ＜０．７％。

STUDY ON PREPARATION OF AMORPHOUS BORON POWDER BY HEATING REDUCTION WITH MAGNESIUM

The boron powder prepared by traditional heating reduction with magnesium is lower in purity and contains high impurities,such as Mg,O.To solve this problem,the effect of material proportion and reactant size on product purity when preparing boron powder from B_2O_3 by heating reduction with magnesium is discussed in this paper. And the reason for this effect is analysed at the same time.The effect of heat preservation of reaction on product structure is investigated.It is found that when the reaction is completed,the material should be cooled rapidly.Othetwise, the insoluble compound Mg_3 (BO_3)_2 will be formed along with the extension of time of heat preservation, leading to higher content of Mg, O of boron powder.The heating oxidation dacomposition is put forward to be used for decreasing of oxygen and removing magnesium from insoluble compounds,such as B_6O, B_7O, MgB_x formed in reaction. The technological conditions and results have been tested. The pure boron powder obtained contains B>95%, Mg <0.7%.