In this research at first, B 4 C synthesis was performed in magnesiothermic reaction with commercial boron oxide. High hygroscopic nature and also lack of desired particle size of commercial boron oxide caused problems such as formation of HBO 2 and Mg(OH) 2 compounds in the initial mixture during milling. On the other hand, explosion and severe fragmentation of sample during combustion synthesis process was caused that the combustion wave during synthesis, was not observed and not examined. Also, increasing magnesium borate phase in combustion synthesis product caused difficult acidic leaching condition and thus remaining this phase in the product. Therefore, according to the results and ensuring failure of commercial boron oxide (due to the extreme hygroscopic nature) in relation to the production of B 4 C with good efficiency during magnesiothermic process, production issue of B 2 O 3 from boric acid were examined for achieving its key properties to compensate for the boron oxide inefficiency (particle size, surface morphology, hygroscopic nature). For this purpose, three methods, including methods of fusion, non-fusion and chemo-thermal method were examined. The results of fusion and non-fusion methods showed that due to the failure to remove hygroscopic nature and also the lack of access to appropriate particle size and morphology, the product of these two methods have similar behavior with commercial B 2 O 3 and therefore it is not efficient. Thus,
