The spinel (Mg,Si)Al2O4 was synthesized from aluminum dross using an induction synthesis method. X-ray diffraction analyses on products formed at different temperatures provided an understanding of the formation mechanism of the spinel. After removal of soluble components, the induction heating of the dross resulted first in the oxidation of some of the AlN component and the subsequent formation of the spinel by the following reaction: xSiO(2) + (1-x)MgO + [1-(x/3)] Al2O3 + (2x/3)AlN = (Mg1-xSi)Al2O4 + (x/3)N-2(g).