Recovering copper foil from scrapped printed circuit boards using molten tin bath in treating furnace

摘要

Waste printed circuit boards, having copper foil, thermosetting plastic, and glass fiber, are recycled in a bath of molten tin or tin alloy. They are agitated and stirred to peel off the copper foil while the plastic is carbonized. The copper foil, carbonized plastic, and glass fibers form separate layers. The last two are removed from the upper surface of the molten tin bath using a floating scraper (5) and fixed amounts of the copper foil are removed at regular intervals. The removed carbonized thermosetting plastic residues, glass fibers, and copper foil are stored in separate collection tanks (8,9). A burning device (2) destroys most of the volatile gases produced by carbonizing the plastic. Remaining volatile gases are led into a combustion chamber (7) and transformed to stable gas.