The nucleation and crystallization kinetics of new glasses obtained by melting mixtures of a Spanish carbon fly ash with glass cullet and dolomite stag at 1500 degreesC has been evaluated by a calculation method. These glasses, whose microstructure was examined by TEM carbon replica, were susceptible to controlled crystallization in the 800 degrees -1100 degreesC range. The resulting glass-ceramics developed acicular and branched wollastonite crystals or a network of dendritic pyroxene mixed with anorthite feldspar (SEM and EDX analysis). The time-temperature-transformation curves (processing of the XRD data) showed the crystallization kinetics and the critical cooling rate to be in the 12 degrees -42 degreesC/min range.