燃煤灰渣火山灰反应活性

POZZOLANIC REACTIVITY OF COAL ASHES

利用活性SiO2,Al2O3与石灰水化反应产物可溶解于稀盐酸的特性,对2种粉煤灰、2种沸腾炉渣和4种流化床固硫灰渣中具有火山灰活性的SiO2,Al2O3反应动力学进行了研究,并以此来评估不同种类燃煤灰渣的火山灰反应活性。结果表明:所采用燃煤灰渣的活性SiO2,Al2O3火山灰反应均符合一级反应动力学模型;活性Al2O3反应速率常数大于活性SiO2,而表观活化能相反;沸腾炉渣和流化床固硫灰渣火山灰活性接近,均明显高于粉煤灰;高温对粉煤灰火山灰活性的激发更为有利。

The pozzolanic activity of coal ashes can be evaluated by the kinetics of pozzolanic reaction. The kinetics of pozzolanic reaction of two types of pulverized coal （PC） ash, two types of bubbling fluidized bed combustion （BFBC） ash and four types of circulating fluidized bed combustion （CFBC） ash was investigated based on the fact that the reaction products of active SiO2, Al2O3 and lime are soluble in low concentration hydrochloric acid. The results show that the pozzolanic reaction of active SiO2 and Al2O3 conforms to the Class I model of kinetics. The reaction rate constant of active Al2O3 is higher than that of active SiO2, while the activation energy is just the opposite. It was confirmed that the pozzolanic activity of BFBC ash and CFBC ash was significantly higher than that of PC ash, and a higher temperature is more favorable to the activation of PC ash than to BFBC or CFBC ash.