THE EFFECT OF Mg-Al Wt% FOR PHASE FORMATION OF SPINEL MgAl2O4 PRODUCED BY METAL DISSOLVED METHOD

Abstract

Synthesis of magnesium aluminate spinel powder (MgAl₂O₄, abbreviated as MA) were prepared by the liquid mixing method. The synthesis of MA involved Mg powders with various weight compositions (4.8; 10; 20; 30; 40; and 60%) and Al powders (95.2; 90; 80; 70; 60 and 40%) as the raw materials, which were independently dissolved in 37% HCl to form MgCl₂ and AlCl₃ solutions. Both solutions were then mixed and stirred for 5 hours and dried to a temperature of about 100-105°C to produce powders with different weight compositions. Each powder resulted from drying was characterized using DTA-TGA, and then calcined at 650 °C; 750 °C and 850 °C for 1 hour. The calcined powder was characterized by XRD to qualitative and quantitative analyses using Rietica. It was found that MA samples contained only MgAl₂O₄ and MgO as the impurity phase. The relative weight fraction of MgAl₂O₄ increased up to 99% for 95.2 wt% Al. Using an extrapolative approach to determine the Mg-to-Al composition, nearly pure MA, as high as 99%, was achieved at 95.2% Al and 4.8% Mg.