RECOVERY OF METALS FROM E-SCRAP

Abstract

The ever-increasing demand for new electronic devices due to technological advancements is resulting in a rise in toxic waste. PCB’s have almost 30% of metal fraction present in them which can be recovered. Hydrometallurgical process promises to be an effective recycling process from WPCB. The recycling process employed in this report uses large pieces of PCB (4x4cm) rather than a pulverized sample due to which process steps are decreased and is easier to perform. The solder mask present on the PCB is removed using alkali hydroxides NaOH-KOH prior to the acid dissolution. Hydrochloric acid is used for the effective removal of metals and as the acid concentration increased the metal recovery increased and time taken for complete dissolution decreased. To further decrease the reaction time oxidant was used (H2O2) which resulted in complete recovery of metals in just 8 minutes. The time for copper extraction has significantly decreased due to the oxidative effect of H2O2. Electrodeposition technique is used to recover the dissolved copper from acid solution using stainless steel as a cathode. BER which acts as a binding agent in PCBs is effectively dissolved using DMF. Different layers in PCB are delaminated due to the absence of BER and copper along with plastics are recovered by manual dismantling after the dissolution. Optimum time and particle size (1x1cm) are established for better recovery. An attempt has been made to recover metals by physical separation process i.e. magnetic separation and dense media separation.