Chemical Recovering of Epoxy Resin and Glass Fibers from Waste Printed Circuit Boards

摘要

A chemical process was carried out for recovering epoxy resin and glass fibers from the nonmetallic powders from waste printed circuit boards (PCBs). Having removed a small amount of dust and metal residues, the non-metallic powders was put into nitric acid and heated to make the thermosetting resins decompose. At the end of the reaction, the glass fibers as the only solid residue were collected by filtration, and the epoxy resin was obtained from the acid solution by extraction with ethyl acetate. Glass fibers and epoxy resin were received in high yields. No thermosetting epoxy resin appearing around the surface of the glass fibers obtained was observed under scanning electron microscope. The backbone of the recovered epoxy resin was similar to that of the thermosetting epoxy resin contained in the waste PCBs proved by FT-IR spectrum. The effects of nitric acid concentration, temperature, and liquid/solid ratio on decomposition time were discussed. The results shows that the decomposition time decreases with increase of nitric acid concentration at same temperature and liquid/solid ratio, decreases with increase of temperature in same concentration of nitric acid and liquid/solid ratio, and decreases with increase of liquid/solid ratio in same concentration of nitric acid and at same temperature.