Molten Salt Synthesis of Magnesium Aluminate (MgAl ₂ O ₄ ) Spinel Powder

Abstract

MgAl 2 O 4 (MA) spinel powder was synthesized by heating an equimolar composition of MgO and Al 2 O 3 in LiCl, KCl, or NaCl. The synthesis temperature can be decreased from >1300°C (required by the conventional solid–solid reaction process) to ∼1100°C in LiCl, or to ∼1150°C in KCl or NaCl. The molten salt synthesized MA powder was pseudomorphic and retained, to a large extent, the size and morphology of the original Al 2 O 3 raw material, indicating that a “template formation mechanism” plays an important role in the synthesis process.