水洗对焚烧飞灰中氯及重金属元素的脱除研究

为了研究水洗对飞灰中氯和重金属元素的脱除影响因素,确定水洗最佳参数并分析水洗的脱除机理,对飞灰的水洗过程进行了系统的研究。结果显示:当液固比为8、水洗时间10 min、水洗温度50℃、水洗1次时,氯的去除率达93.71%以上;水洗脱氯的过程包括溶解和脱附两部分,当液固比20 mL/g时,以脱附为主;同时飞灰中的重金属在水洗过程中也有不同程度的脱除,其中Pb的脱除率和在水洗液中的浓度较大。

STUDY ON THE REMOVAL OF CHLORINE AND HEAVY METALS IN INCINERATION FLY ASH DURING WATER-WASHING PROCESS

In order to study the effects of water-washing process on the removal of chlorine and heavy metals in fly ash,determine the optimum water-washing parameters and analyze the removal mechanism of water-washing process,the water-washing process was studied systematically.The results showed that water-washing process could remove more than 93.71% of chlorine when liquid-to-solid(L/S) was 8,water-washing time was 10 min,water-washing temperature was 50℃ and water-washing frequency was 1.The water-washing process for removing chlorine included dissolution process and desorption process,when the L/S was less than 20 mL/g,dissolution process was the dominant one and when the L/S was more than 20 mL/g,desorption process was primary.At the same time heavy metals in fly ash also could be partially removed,especially the elution rate and concentration of Pb in water solution were larger.