Optimization of an Electrochemical Process for Recycling Metals from Electronic Waste
Luis A. Diaz, Tedd E. Lister, Gemma G. Clark
Idaho National Laboratory
P.O. Box 1625
Idaho Falls, ID 83415-3731
The proper disposal and recycling of electronic waste is a growing environmental issue due to the increasing demand and the reduction of their life cycle . Besides being considered a hazardous waste due to the presence of toxic elements, electronic wastes are significant sources of valuable metals available for recycling. Value metals in electronics include gold, palladium, silver, copper, cobalt, nickel, and rare earth elements [2, 3]. While, metal recovery strategies are being encouraged by new policies and growing interest in urban mining , the recovery of metals is usually performed using-low tech methods or with an extensive use of chemicals, which exacerbate the ecological damage and directly affects health issues for workers and local communities.
Within the development of new technologies for the recycling of metals from electronic waste, electrochemical methods are recognized as a greener technology for the extraction of metals with minimum chemical consumption . Although, the range of electrochemical generated oxidants is broad regarding the strength and target metals to be extracted, the approach taken in this research involves using a weaker oxidizer (Fe+3/+2) that attacks the base metals (Cu, Sn, Zn, Ni) in the non-ferrous fraction of electronic waste. This approach has been taken as the remaining small concentrations of precious metals can be selectively and efficiently extracted with minimum chemical consumption.
In this process an electrochemical reactor operates in recirculation with the lixiviation of metals from milled electronic waste. The leachate from the metal lixiviation is returned to the cathode side of the cell for recovery of extracted metals at the cathode and flows to the anode for the oxidant regeneration. The results of an optimization process performed by means of a surface response analysis combined with the simulation of the lixiviation process to reduce the energy consumption and enhance the metal recovery efficiency will be presented.
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