【摘要】 高含量的氯和重金属是生活垃圾焚烧飞灰资源化利用和处置的制约因素,在工程利用处置中,通常需要对飞灰进行脱氯或去除重金属等预处理,以满足工艺生产和环境安全的要求。研究了不同酸浸洗液(乳酸、硝酸、磷酸)对飞灰中氯和重金属洗脱效率的影响。结果表明,飞灰样品中氯的脱除率随着浸洗液pH降低逐渐上升;不同酸浸洗液对飞灰的脱氯率有较大差异。当pH相同时,乳酸由于其良好的缓冲体系能提供更多的酸度使其脱氯效果最好。当浸洗液浓度相同时,硝酸的脱氯效果最好,磷酸其次,乳酸最差,最佳脱氯率分别为93.86%、92.22%和90.83%。飞灰中重金属在酸溶液中更容易被脱除,但脱除率与酸浸洗液的种类及重金属种类有关,对重金属去除效果为:硝酸>乳酸>磷酸。3种酸对重金属(Zn、Pb、Cu、Cd、Cr)的去除率分别为12.27%、10.07%和1.68%,其中去除效果最好的硝酸对这5种重金属的去除率分别为3.27%、62.76%、23.73%、0.013%、3.15%。更多还原

【Abstract】 High content of chlorine and heavy metals are the limiting factors for the resource utilization and disposal of MSW fly ash. In engineering utilization and disposal,pre-treatment such as dechlorination or heavy metal removal of fly ash is normally required,to meet the requirements of process production and environmental safety. The influence of different pickling lotion(lactic acid,nitric acid,and phosphoric acid)on the elution efficiency of chlorine and heavy metals in fly ash was researched. The results showed that the removal rate of chlorine in the fly ash samples gradually increased as the pH of the pickling lotion decreased,and the dechlorination rate of fly ash by different pickling lotion were quite different. When the pH was the same,due to its good buffer system,lactic acid could provide more acidity to make its dechlorination the best. When the concentration of the leaching lotion was the same,nitric acid had the best dechlorination effect,followed by phosphoric acid,and the worst was lactic acid,the best dechlorination rates were 93.86%,92.22%,and 90.83%,respectively. Heavy metals in fly ash were more easily removed in acid solutions,but the removal rate was related to the type of acid leaching lotion and the type of heavy metals,the removal effect on heavy metals was nitric acid,lactic acid and phosphoric acid in that order. The removal rates of heavy metals(Zn,Pb,Cu,Cd,Cr)by those three acids were 12.27%,10.07% and 1.68%,respectively. Among them,the removal efficiency of the five kinds of heavy metals were 3.27%,62.76%,23.73%,0.013%,3.15%,respectively by nitric acid,which had the best removal effect.更多还原