Cagnetta Giovanni, Hassan Mohammed Mansour, Huang Jun, Yu Gang, Weber Roland
State Key Joint Laboratory of Environment Simulation and Pollution Control (SKJLESPC), Beijing Key Laboratory of Emerging Organic Contaminants Control (BKLEOCC), School of Environment, POPs Research Center, Tsinghua University, Beijing 100084, P. R. China.
POPs Environmental Consulting, Lindenfirststrasse 23, 73527 Schwaebisch Gmuend, Germany.
Sci Rep. 2016 Mar 15;6:22925. doi: 10.1038/srep22925.
Secondary copper recovery is attracting increasing interest because of the growth of copper containing waste including e-waste. The pyrometallurgical treatment in smelters is widely utilized, but it is known to produce waste fluxes containing a number of toxic pollutants due to the large amount of copper involved, which catalyses the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans ("dioxins"). Dioxins are generated in secondary copper smelters on fly ash as their major source, resulting in highly contaminated residues. In order to assess the toxicity of this waste, an analysis of dioxin-like compounds was carried out. High levels were detected (79,090 ng TEQ kg(-1)) in the ash, above the Basel Convention low POPs content (15,000 ng TEQ kg(-1)) highlighting the hazardousness of this waste. Experimental tests of high energy ball milling with calcium oxide and silica were executed to assess its effectiveness to detoxify such fly ash. Mechanochemical treatment obtained 76% dioxins reduction in 4 h, but longer milling time induced a partial de novo formation of dioxins catalysed by copper. Nevertheless, after 12 h treatment the dioxin content was substantially decreased (85% reduction) and the copper, thanks to the phenomena of incorporation and amorphization that occur during milling, was almost inactivated.
由于含铜废料（包括电子垃圾）的增加，二次铜回收越来越受到关注。冶炼厂的火法冶金处理被广泛应用，但由于涉及大量铜，已知会产生含有多种有毒污染物的废渣，这些废渣会催化多氯二苯并对二恶英和二苯并呋喃（“二恶英”）的形成。二次铜冶炼厂中，飞灰是二恶英的主要来源，会导致残渣受到高度污染。为了评估这种废料的毒性，对二恶英类化合物进行了分析。在灰渣中检测到高水平的二恶英（79,090 ng TEQ kg⁻¹），高于《巴塞尔公约》规定的低持久性有机污染物含量（15,000 ng TEQ kg⁻¹），突出了这种废料的危险性。进行了用氧化钙和二氧化硅进行高能球磨的实验测试，以评估其对这种飞灰解毒的有效性。机械化学处理在4小时内使二恶英减少了76%，但更长的研磨时间会导致由铜催化的二恶英部分从头形成。然而，经过12小时处理后，二恶英含量大幅下降（减少了85%），并且由于研磨过程中发生的掺入和非晶化现象，铜几乎失去了活性。
