Abstract: Waste printed circuit boards (WPCBs) are rich in valuable metals such as copper, tin, lead, and zinc, demonstrating significant resource recovery potential. However, during the pyrometallurgical recovery process, the migration behavior of volatile elements such as Sn, Pb, and Zn directly affects metal recovery efficiency and environmental emissions. This work systematically investigated the effects of key process parameters—including temperature, CaO addition, Fe/SiO2 mass ratio, and oxygen enrichment concentration—on the distribution of Sn, Pb, and Zn among the three phases (gas, slag, and matte phase) during the co-smelting of waste WPCBs with copper concentrate. By combining microscopic characterization with thermodynamic calculations, the occurrence forms and migration mechanisms of these elements in each phase were elucidated. The results showed that Sn was primarily distributed in the gas phase, followed by the slag and matte phases. Pb also preferentially entered the gas phase, followed by the matte and slag phases. Zn was mainly enriched in the slag phase, and then in the gas and matte phases. By adjusting the co-smelting process parameters, the directional migration of target elements could be achieved: the volatilization of Sn and Pb into the gas phase was significantly enhanced with increasing temperature, while controlling the Fe/SiO2 mass ratio and CaO addition within an appropriate range favored the selective enrichment of Zn in the slag phase. Microscopic characterization confirmed that in copper slag, Sn existed as SnO, Pb as PbO, and Zn as ZnFe2O4. In the matte phase, Sn formed intermetallic compounds with Cu, Pb occurred as alloy, and Zn was distributed as ZnS. This study provides experimental evidence and theoretical reference for the targeted control and resource recovery of impurity elements during the co-smelting of WPCBs with copper concentrate.

Key words: waste printed circuit boards, copper concentrate, co-smelting, element migration, Sn, Pb, Zn

摘要： 废旧电路板富含铜、锡、铅、锌等有价金属，具有显著的资源回收潜力，但其火法回收过程中Sn, Pb, Zn等易挥发元素的迁移行为直接影响金属回收效率与污染物排放。本工作系统研究了废旧电路板与铜精矿协同熔炼过程中温度、CaO添加量、Fe/SiO2质量比及富氧浓度等关键工艺参数对Sn, Pb, Zn在三相(气相、渣相和铜锍相)中分配规律的影响，借助微观表征手段并结合热力学计算，阐明了其在各相中的赋存形态与迁移机制。结果表明，Sn主要分布于气相，其次为渣相与铜锍相；Pb同样优先进入气相，随后分布于铜锍相与渣相；Zn则主要富集于渣相，其次为气相与铜锍相。通过调控协同熔炼工艺参数，可实现目标元素的定向迁移：升高温度可显著促进Sn和Pb向气相挥发；而将Fe/SiO2质量比与CaO添加量控制在适宜范围，则有利于Zn在渣相中选择性富集。微观表征证实，铜渣中Sn以SnO、Pb以PbO、Zn以ZnFe2O4形式存在；而铜锍中Sn与Cu形成金属间化合物，Pb以合金形式富集，Zn以ZnS形式分布。本研究为废旧电路板与铜精矿协同熔炼过程中杂质元素的定向调控与资源化回收提供了实验依据与理论参考。

关键词: 废旧电路板, 铜精矿, 协同熔炼, 元素迁移, Sn, Pb, Zn