抄録
In order to efficiently capture Na and K in solid during heat treatments of coal, two kinds of phyllosilicate (kaolinite and pyrophylite) were added to low-rank Yallourn and Barau coals which contained high contents of volatile H_2O-soluble and ion-exchangeable fractions of these alkali metals. By addition of kaolinite, more than 90 % of alkali metals in these raw coals remained in solid phase after pyrolysis and CO_2 gasification. For Yallourn coal, 1wt.% of kaolinite addition was enough to control K release during heat treatments. On the other hand, it was needed to add high content of kaolinite (10 wt.%) for Na capture. A possible reason was ascribed to change of H_2O-soluble Na to H_2O-insoluble at higher temperature 600〜900℃, compare to the case of K.
