对改性粉煤灰中硅铝铁溶出率的研究

A Study of the Dissolution Rates of Silicon, Aluminum and Iron from Modified Fly Ash

在高温焙烧、碱溶和酸浸等条件下对粉煤灰进行改性，提取粉煤灰中的活性成分硅铝铁。采用EDTA络合滴定法确定Fe3＋的浓度，CuSO4返滴定法确定Al3＋的浓度。研究了粉煤灰的活性成分在活化改性时的最佳焙烧条件。实验结果表明，粉煤灰中Fe3＋、Al3＋的最佳溶出条件为：焙烧温度800℃，焙烧时间为1．5h，粉煤灰与氢氧化钠的质量比为3：1。酸浸时间1h时，碱溶温度为150℃时，Al3＋和Fe3＋硅溶出率最高。

In the process of the high temperature roasting, the alkali dissolving and the acid pickling, the modified fly ash was made, and then silicon, aluminum and iron, the active ingredients were extracted. The concentration of Fe3＋ was determined by EDTA complexometric titration, and the concentration of Al3＋ was determined by CuSO4 back titration respectively. The best roasting conditions of the active ingredients in fly ash in dissolution were studied. The experimental results showed that the best conditions in dissolution of Fe3＋ and Al3＋ of fly ash was that the roasting temperature was 800℃ ; the time is about 1.5h; the fly ash and sodium carbonate were mixed by 3：1. When the time of the extracting the mixture by hydrochloric acid about lh and extracting the mixture by sodium carbonate with 150℃, the dissolution rate of silicon could achieve highest ratio.