GB1064093A - Purification of boron - Google Patents

Abstract

In the separation of finely divided particles of elemental boron from finely divided particles of one or more impurity materials admixed therewith, a mixture of the boron particles, impurity particles, water and oleic acid is vigorously agitated, the boron particles are allowed to settle, and the boron particles are physically separated from the liquid medium which retains impurity particles. The treatment may be repeated one or more times when there is present a large proportion of impurity, for example iron, carbon, boron carbide, iron carbide or mixtures thereof. The volume of water in the mixture preferably is equal to or greater than the volume of the impure boron; the amount of oleic acid used preferably is between 0.005% and 0.05% by volume of the water present in the mixture. After separation, which may be by decantation and/or filtering, additional traces of impurity may be removed from the boron particles by washing, for example with hot water and then with ethyl alcohol or carbon tetrachloride, the organic liquid also removing water absorbed on the surface of the boron particles; the latter may then be vacuum dried.ALSO:In the separation of finely divided particles of elemental boron from finely divided particles of one or more impurity materials admixed therewith, a mixture of the boron particles, impurity particles, water and oleic acid is vigorously agitated, the boron particles are allowed to settle, and the boron particles are physically separated, for example by decantation and/or filtering, from the liquid medium which retains impurity particles. The treatment may be repeated one or more times when there is present a large proportion of impurity, for example iron, carbon, boron carbide, iron carbide or mixtures thereof. The volume of water in the mixture preferably is equal to or greater than the volume of the impure boron; the amount of oleic acid used preferably is between 0.005% and 0.05% by volume of the water present in the mixture. After separation, additional traces of impurity may be removed from the boron particles by washing, for example with hot water and then with ethyl alcohol or carbon tetrachloride, the organic liquid also removing water absorbed on the surface of the boron particles; the latter may then be vacuum dried.