粉煤灰中SiO_2在不同碱性条件下的溶出量及与火山灰活性指数的关系

SOLUBLE SiO_2 CONTENT IN FLY ASH UNDER DIFFERENT ALKALI CONDITIONS AND THE RELATIONSHIP BETWEEN THE CONCENTRATION AND POZZOLANIC ACTIVITY INDEX OF FLY ASH

采用沸煮法,对Ca(OH)2+NaOH溶液的pH值对粉煤灰的SiO2溶出量的影响进行了研究;同时探讨了粉煤灰的可溶性SiO2量与其火山灰活性指数的关系。结果表明:碱激发溶液的pH值越高,粉煤灰的SiO2溶出量越大;粉煤灰的SiO2溶出量在碱溶液的pH值超过某一特定值后显著增加,表现出较高的活性。采用Ca(OH)2+NaOH混合溶液测定粉煤灰的SiO2溶出量,与实际情况较为吻合。粉煤灰的总SiO2含量越高,SiO2溶出量越高,反之越低;SiO2溶出率与总SiO2含量无关,粉煤灰的可溶性SiO2量和SiO2溶出率与其火山灰活性指数之间没有相关性。

The influence of the pH value of Ca（OH）2＋NaOH solution to soluble SiO2 content in fly ash was studied by the boiling reflux method, and the relationship between soluble SiO2 content and the pozzolanic activity index was discussed. The soluble SiO2 content increases with the pH value of solutions. The soluble SiO2 content increases remarkably and fly ash shows obvious activity when the pH value of solutions exceeds infinity. This is coincidental with the real situation to determine the soluble SiO2 content in fly ash using Ca（OH）2＋NaOH blended solution. The more SiO2 is contained in fly ash, the more SiO2 can be dissolved, and vice versa. There is no correlation between the dissolution rate and the total SiO2 content. The pozzolanic activity index of fly ash is independent of the soluble SlOE content and dissolution rate of SiO2.