Recycling non-leaching gold from gold-plated memory cards: Parameters optimization, experimental verification, and mechanism analysis

摘要

Large amounts of gold generally plated on printed circuit boards that drives unregulated activities to recycle it with serious adverse consequences to the environment and human health, demanding innovative strategies to solve this problem. This paper presented a novel, efficient and safer strategy to recover non-leaching gold from waste memory cards by using the renewable agent ammonium per sulfate and hydrogen peroxide, which were evaluated in terms of efficiency and kinetics. The tests were conducted in a response surface methodology design called central operation design. The results showed that the optimal conditions were 0.8 mol/L of ammonium persulfate concentration (1:30 of solid/liquid ratio), 14.45 mL of hydrogen peroxide dosage, 80 degrees C of reaction temperature and 30 min of reaction time, under which the recovery rate of gold was 98.95% with 93.105% purity. This process of gold peeling agreed with the shrinking core model controlled by diffusion. All findings demonstrated that combination of ammonium persulfate and hydrogen peroxide has a good performance for oxidizing base metal substrate and peeling superficial gold from memory cards. (C) 2017 Elsevier Ltd. All rights reserved.