高温烟气热解废轮胎过程中痕量金属Cu、Pb的迁移特性分析

Transformation of trace metals Cu and Pb during high temperature flue gas pyrolysis of waste tires

废轮胎(WT)作为一种常见固废,不合理的处置会对环境造成较大污染。本文采用燃煤高温烟气对WT进行热解,重点研究了热解过程中重金属Cu和Pb的释放特性,以及不同金属氧化物(CaO、MgO、Al_(2)O_(3)、Fe_(2)O_(3))对两种重金属的控制效果,此外还研究了添加聚氯乙烯(PVC)对两种重金属迁移释放的影响。结果表明,当热解时间为10min时,两种元素已经基本释放完全。高温促进了Cu的富集,而低温反而促进了Cu的释放。对Pb元素而言,随着温度的升高,其释放量不断增加,展现出明显的线性规律。当WT添加金属氧化物热解时,MgO促进了Cu的富集,而Al_(2)O_(3)促进了Pb的富集。当WT添加PVC热解时,低温促进了Cu的富集,而高温促进了Cu的释放。但不论温度的高低,PVC的添加使得Pb几乎完全释放。此时,添加Fe_(2)O_(3)对两种重金属的释放均起到了抑制作用。

Waste tires(WT),as a common solid waste,can cause great pollution to the environment if it is disposed unreasonably.In this paper,coal-fired high-temperature flue gas for pyrolysis of WT was used,focusing on the release characteristics of heavy metals Cu and Pb during the pyrolysis process,and the control effects of different metal oxides(CaO,MgO,Al_(2)O_(3),Fe_(2)O_(3))on two heavy metals.In addition,the effect of adding PVC on the migration release of two heavy metals was also investigated.The results showed that when the pyrolysis time was 10min,the two elements had been basically released completely.The enrichment of Cu was promoted at high temperature,while the release of Cu was promoted at low temperature.Metal oxides had a controlling role in the release of two elements.MgO promoted the enrichment of Cu,while Al_(2)O_(3) promoted the enrichment of Pb.When WT with added polyvinyl chloride(PVC)was pyrolyzed,the enrichment of Cu was promoted at low temperature while the release of Cu was promoted at high temperature.However,regardless of the temperature,the addition of PVC resulted inalmost complete release of Pb.Furthermore,Fe_(2)O_(3) inhibited the release of both heavy metals.