Emission characteristics of dioxins in the whole process during the collaborative disposal of waste circuit boards by Ausmelt furnace
Collaborative thermal treatment of waste circuit boards(WCBs)can effectively recovery metal resources,however,the emission of dioxins during the disposal process needs to be of concern.To investigate the emission characteristics of dioxins during the collaborative disposal of WCBs in Ausmelt furnace,the concentration distribution and fingerprint characteristics of dioxins in the fuel,slag,flue gas,and electrostatic defogging wastewater were studied.Furthermore,the mass balance analysis of dioxins in the whole process was also carried out,and SEM,XRD,XPS characterization was performed on slag,fly ash,etc.The research results indicated that the concentrations of dioxin at the front end of electric defogging unit,the outlet of acid making chimney,and environmental gas collection chimney were all lower than the emission limit of 0.1 ng·Nm-3.Replacing a small amount of traditional fuel with WCBs will not increase dioxin emissions.The mass balance analysis showed that the net emission of dioxins during collaborative disposal process was-8.804 mg·d-1(-4.61 mg·d-1),and the proportion of dioxins contained in slag and flue gas was the highest,indicating that The collaborative disposal process of WCBs by Ausmelt Furnace is a process of reducing dioxins.The characterization results of slag,fly ash,etc.show that that more copper and carbon participated in the copper oxychlorination cycle during the collaborative disposal.The minerals in slag could capture high chlorinated dioxins through adsorption,while the dioxins adsorbed by fine fly ash undergo simultaneous desorption and degradation.The results of this study will provide a theoretical basis for the control of dioxin emissions during the collaborative disposal of WCBs by Ausmelt furnace.
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