End-of-life electronic devices such as smartphones, computers, televisions, and other electronics contain significant amounts of valuable metals including base metals (zinc, tin, lead, nickel, and copper), precious metals (silver, gold, and palladium), and rare earth magnets (neodymium, yttrium, samarium). Some electronic scrap is currently landfilled or incinerated, and there is a need to develop more effective processes to capture these valuable metals along with keeping them out of the environment.
The bulk of electronics processed for metal recovery is sent overseas, using unsustainable acid-solution leaching or toxic smelting processes that lack environmental and worker safety practices. In many cases, only the precious metals such as gold and palladium are targeted.
A technology was developed to reclaim valuable metals from waste electronic equipment. The electrochemical recovery from metal waste method uses an electrochemical cell to efficiently recover the bulk of metals from discarded electronics, leading to more complete recycling of materials while significantly minimizing chemical use and waste generation. The Electrochemical Recovery (ER) process is capable of dissolving the major metals found in electronics, and can be used on materials that have been shredded, magnetically separated, or milled to a particle size below one millimeter.
The ER process generates oxidizing agents at an anode to dissolve metals from the scrap matrix while reducing dissolved metals at the cathode. The process uses a single cell to maximize energy efficiency.
The ER process allows “e-waste” aggregators to reclaim more value materials, reduce reagent use, and lessen the toxicity of remaining materials compared with current practices for salvage of metals from waste electronics. The ER process also efficiently recovers and separates base metals copper, tin, and silver. The process allows the precious metals silver, gold, and palladium to be recovered in a separate follow-up step. The ER process continuously regenerates the initial oxidizer at the anode, giving the process solution a long life, resulting in significant savings in reagents and waste treatment.