Selective Desoldering Separation of Tin-Lead Alloy for Dismantling of Electronic Components from Printed Circuit Boards

Desoldering separation of solder from waste printed circuit boards (PCBs) is a key step to recycle or dispose the electronic waste effectively. In the present work, a novel way for selective desoldering separation was achieved by dissolving lead tin solder in fluoroboric acid containing H2O2. This leachant was observed possible to take the solder into solution with negligible dissolution of copper or other metals within 35 min. After leaching, the electronic components (ECs) could be easily removed from the boards under good experiment conditions. The effects of oxidants, dosage of H2O2, and acid concentration were explored to obtain the suitable experimental conditions. The results showed that 2.5 mol/L fluoroboric acid containing 0.4 mol/L added oxidant H2O2 within the reaction of 35 min could be regarded as the optimum conditions for the selective desoldering separation from the waste PCBs. Both theoretical analysis using HSC Chemistry software and actual waste PCBs examination novel process via excess solder added to inhibit the effect of copper dissolution if exists. This safe, fast, economic, and environmentally friendly dismantling PCBs process would be of great importance in recycling waste electrical and electronic equipment (EEE) effectively.