GIBBS FREE ENERGIES OF FORMATION OF INDIUM(III) OXIDE AND SULPHATE.

Accurate information on the free energies of formation of oxides and sulfates is of importance for the selection of preferential sulfation conditions in mineral processing. The standard free energy of formation of In//2(SO//4)//3 has not been measured previously. A differential thermal analysis (DTA) technique was employed in this investigation to determine the decomposition temperatures under controlled streams of SO//2 plus O//2 plus Ar gas mixtures. Since thermal segregation in the gas mixture can be considerably reduced in flowing systems, this method is superior to static techniques for the measurement of decomposition pressures.