As contributions of non-ferrous smelters to metal resource circulation, ores and secondary raw materials, such as scrap and waste, are treated to recover base metals such as copper, lead, and zinc, as well as other precious and minor metals. One crucial factor that makes this metal recovery possible is the creation of an organic link among copper, lead, and zinc smelters. In recent years, the specialization of non-ferrous smelting companies has been promoted in Japan, and it has become difficult to maintain this close organic link. In addition, in the field of metal resource circulation, the importance of lead smelters should be recognized again. For example, lead smelting acts as an essential destination for copper smelting by-products, such as smelting dusts. Additionally, printed circuit boards that have been treated in large quantities in copper smelters contain metal impurities, such as lead and tin in solder and antimony in flame-retardant auxiliaries. When printed circuit boards are treated in copper smelters, these excess impurities may interfere with the copper smelting process and accumulate in by-products. These impurity metals can be recovered effectively in lead smelters.