Preparation of high energetic solid fuel amorphous boron powder and microstructure of combustion products

It is necessary to explore new technique that might obtain the high grade amorphous boron powder. The reductive process was investigated on preparing the boron powder by the magnesiothermic reduction of B2O3. The boron powder with 94.6%B content was obtained with B2O3/Mg (wt) ratio 3.0, the systematic temperature 850 degrees C, Mg particle size 100-200 mesh, B2O3 particle size 80-100 mesh and the time of constant temperature 30min. During process of combustion, the excess B203 was combined with the product MgO into the compounds xMgO center dot B2O3 (x=3, 2) which was a little difficult to be dissolved by acid. The XRD spectrums of combustion products before and after acid leaching show that MgB6 is made by the product B and Mg. Mg2SiO4 is combined by the product MgO and SiO2 and FeB49 is combined by the product B and a little Fe2O3. The grade of boron powder is affected by insoluble matter MgB6, Mg2SiO4, FeB49 and a little difficult insoluble matter xMgO center dot B2O3.