Thermogravimetrische Untersuchung der reduzierenden Chlorierung von Tonerde

Thermogravimetric analysis of the reducing chlorination of alumina The kinetics of the chlorination of dehydrated alumina with (CO/Cl₂) mixtures were studied in the temperature range of 400–900°. The temperature of dehydration of the alumina was shown to be critical for the reaction rates of the subsequent chlorination. Optimal reaction rates could be observed with equimolar (CO/Cl₂) mixtures in the range of 600–700°. At higher temperatures, only a very small increase in reaction rates with increasing temperature could be observed which is thought to be due to the influence of gaseous diffusion gradients in the porous alumina and a progressive decrease in surface area. Granulometric as well as scanning electron microscope studies have shown that with progressing reaction the alumina particles become hollow while retaining their outer shape and size up to a high degree of conversion.