Abstract: (9540 Views)
Boron is known as a high energy density material. This element is an important fuel for propellants and explosives. Of all the chemical elements, boron has the highest volumetric heat of combustion (140 kJ cm-3) and the third highest gravimetric heat of combustion (59 kJ g-1), after H2 and Be. Furthermore, mentioned element is used for the preparation of many alloy compounds. Therefore, study of preparation methods for this strategic element is very important. Boron has two crystalline and amorphous structures that each of these structures has certain applications. According to the references, there are two main techniques to obtain elemental boron powder: 1) reduction method. 2) gas-phase thermal dissociation of boron compound method. Studies are shown that Moissan process (metallothermic method via Mg) is the convential way for preparation amorphous elemental boron. In this method, elemental boron with purity more than 90% can be obtained after acid leaching and washing. Impurities contain Mg-O-B compounds such as Mg(BO2)3, MgB2O5 . Generally, crystalline elemental boron with purity more than 99% can also be prepaered via gas phas. In this paper, various methods for the production of crystalline and amorphous elemental boron, their advantages and disadvantages were investigated.