粉煤灰火山灰反应动力学的研究

Study on the Kinetics of Pozzolanic Reaction of Fly Ashes

用酸溶法测定了粉煤灰 Ca(OH) 2 H2 O系统中粉煤灰的化学未溶量 ,据此建立了低钙粉煤灰的火山灰反应动力学模型 ,并得出粉煤灰的反应速率常数和表观活化能等动力学参数 .结果表明 ,所用的几种低钙粉煤灰的火山灰反应都符合一级反应动力学模型 ,其表观活化能亦可作为评价相应反应性的 1个指标 ;在常温下 ,I级分选灰试样的反应速率常数不如Ⅱ级磨细灰试样 ,但在高温 ( 80°C)下 ,Ⅰ级分选灰试样的反应速率常数则大于Ⅱ级磨细灰试样 .

In this paper, it has been presented that the amount of acid insoluble substance of fly ashes in fly ash Ca(OH) 2 H 2O system are measured by using the acid dissolution method. On this basis, the kinetic model of pozzolanic reaction of fly ash is established. Also, the kinetic parameters, reaction rate constant and activation energy, are obtained. The results show that the pozzolanic reactions of fly ashes conform to the Class I model of kinetics, and the activation energy may act as one of the indexes for evaluating the pozzolanic reactivities of fly ashes. At normal temperature, the afore mentioned kinetic indexes of Class I fly ash collected from selector are not better than those of Class Ⅱ ground fly ashes, but opposite at 80 °C.