Synthesis of non-oxide materials includes solid-phase grinding, liquid building-up, plasma, and CVD. The raw powder of the sintered body is commercialized by solid-state synthesis; however, it is non-spherical in shape and its size is below the submicron range. We considered the changes in free energy of Al, O-2, N-2, NH3, liquefied petroleum gas (LPG) and focused on the reaction accelerator effect of LPG for Al nitridation or Al2O3 reduction. As a result, we found that, conceptually, some Al nitridation syntheses via LPG firing could occur. The LPG firing method can provide a gas diffusion nitridation mechanism, and can therefore produce Al-oxynitride (AlON) directly (Al powder did not convert to AlON completely), and AlN spherical powders with diameters above the submicron range.