关键词: 粉煤灰;碳酸钠;氧化钙;焙烧活化;氧化铝

Abstract: Coal fly ash calcined with sodium carbonate is an effective method to activate the reactivity of aluminum and silicon in it; however, the large consumption of sodium carbonate hinders its industrial application.In this paper,the effect of calcium oxide additive on the sodium carbonate activation of coal fly ash for aluminum extraction was studied by orthogonal experiment and single factor experiment at the medium temperature(600-1000℃).The results show that the sodium carbonate can be partially replaced by adding a certain percentage of calcium oxide in the reaction system at the medium temperature.When the mass ratio of coal fly ash, sodium carbonate, and calcium oxide equaled to 1:0.6:0.2, the dissolution percentage of aluminum from coal fly ash can be more than 90%.Through FT-IR and XRD analysis,it is found that the partial substitution of sodium carbonate by calcium oxide is mainly due to the formation of calcium silicate with the low polymerization degree.

Key words: coal fly ash;sodium carbonate;calcium oxide;activation;alumina