Calcination de-alkali of alkali coal-cinder yielded from catalytic gasification for pulverized anthracite
The effects of calcination temperature, time and additives on the alkali content of coal-cinder from the catalytic gasification of pulverized anthracite were examined by using the static calcination method in a laboratory high temperature furnace in this study.The results indicated that the optimum calcination temperature and time were respectively 870℃and 30 min,and the optimum dealkalization additive is kaolinite.By adding only 5% kaolinite in the calcination process, the dealkalization rate could be increased to 100%.Most importantly, with analyzing the calcined cinder by X-ray powder diffraction (XRD) and scanning electron microscope(SEM), it was clear that at an appropriate calcination temperature, the activated SiO_2 and Al_2O_3 in alkaline coal-cinder would react with the decomposed fused Na_2CO_3 to form a new neutral matter nepheline(NaAlSiO_4)and other amorphous silicate compounds,causing an obvious reduction of the alkali content in coal-cinder.