碱法对粉煤灰的预脱硅处理

Predesilication on fly ash with alkaline solution

在NaOH溶液中,常压下采用加热、搅拌的溶出方式,对某电厂粉煤灰进行预脱硅处理。通过分光光度法和EDTA置换滴定法分别测出溶渣中SiO2和Al2O3的量,计算得出渣中的铝硅比。考察液固比、溶出温度、溶出时间、碱浓度等因素对粉煤灰溶出后渣中铝硅比的影响。结果表明,在液固比为30∶1、温度90℃、溶出时间2h、30%碱浓度(质量分数)条件下,粉煤灰的脱硅率可达58%以上,预脱硅后渣中铝硅比由0.97提高到2.71。

The paper studies the research on predesilication in fly ash with heating and stirring the stripping method in the NaOH solution.Spectrophotometry and EDTA titration were used to measured the amount of SiO2 and Al2O3,and to calculate the Al2O3/SiO2.It inspected more than L/S,temperature,time,alkali concentration,on the impact of Al2O3/SiO2in the slag.It＇s optimum conditions are that L/S is 30∶1,temperature 90℃,time 120 min,alkali concentration 30%.The Al2O3/SiO2 is from 0.97 to 2.71 and the silicon removal rate of fly ash up to 58% after predasilication.