Synthesis of magnesium aluminate spinel by periclase and alumina chlorination

• Use of chlorination for the synthesis of magnesium aluminate spinel.
• The reagents used were alumina, periclase and chlorine.
• Isothermal and non-isothermal assays were performed in air and Cl2–N2 flows.
• The chlorination produced magnesium aluminate spinel at 700 °C.
• Selectivity of the chlorination reaction to obtain spinel is very high.

A pyrometallurgical route for the synthesis of magnesium aluminate spinel by thermal treatment of a mechanical mixture containing 29 wt% MgO (periclase) and 71 wt% Al2O3 (alumina) in chlorine atmosphere was developed and the results were compared with those obtained by calcining the same mixture of oxides in air atmosphere. Isothermal and non-isothermal assays were performed in an experimental piece of equipment adapted to work in corrosive atmospheres. Both reagents and products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD) and X-ray fluorescence (XRF). Thermal treatment in Cl2 atmosphere of the MgO–Al2O3 mixture produces magnesium aluminate spinel at 700 °C, while in air, magnesium spinel is generated at 930 °C. The synthesis reaction of magnesium aluminate spinel was complete at 800 °C.

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