Experimental investigation on the synthesis of calcium aluminates by coal calcination

The operating condition of pulverized coal combustion is similar to aluminium extracting from fly ash in the process of alkali sintering. The ash collected by dust collector in power plant contains high content of alumina when high aluminium coal is burned with calcium-based mineral material additives. In the present paper, alumina synthesis by calcining of ash from coal with high content of alumina was investigated experimentally. Firstly, coal blended with different ratio of limestone was burned in a muffle furnace, and the result from XRD indicates that there is an optimum temperature 1200oC and an optimum ratio of limestone 31.54% for the formation of calcium aluminates. Furthermore, this calcining process was conducted in a drop tube furnace, and the effect of temperature was considered, and the production was also analyzed by XRD. It also demonstrates that the production ratio of calcium aluminates is higher at 1200oC, and the result is consistent with that in muffle furnace.