HYDROTHERMAL REACTIONS OF FLY-ASH WITH CA(OH)(2) AND CASO4-CENTER-DOT-2H(2)O

Hydrothermal reactions of fly ash were investigated. Variations in rea ctivity depended on the presence of added Ca(OH)(2) or CaSO4.2H(2)O. I sothermal calorimetry determined the kinetics of the reactions between fly ash and these compounds. Fly ash was activated by these calcium s alts and activation influenced hydration rates as determined by the ra tes of heat evolution. X-ray diffraction analysis determined the phase s formed as a result of hydrothermal treatment. Calcium silicate hydra te, tricalcium aluminate hydrate and ettringite were observed. The mec hanical properties developed by hydrothermal treatment demonstrates th at hazardous ashes could be consolidated to be handled. Alternatively, non-hazardous ashes can be reacted to form useful products. (C) 1997 Elsevier Science Ltd.