A simple and nearly-closed cycle process for recycling copper with high purity from end life printed circuit boards

• Nearly-closed two-step process for recovering Cu and Al from PCBs residue.
• A first step, based on mild concentrated acid, allowed Cu and Ag extraction with high yield.
• A second step, based on chelating ion exchanger, for Cu purification.
• Recovery of 75% of Cu from the PCBs residue into a Cu solution with 99.0% purity.
• Recovery of 85% of Al, as Al(OH)3, from the raffinate.

The large amount of Cu present in printed circuit boards (PCBs) residues, usually about ten times more than the Cu amount present in rich-content minerals, makes these residues an attractive secondary source of Cu. Thus, the main aim of this work was to develop a simple and nearly-closed two-step process to recover Cu from PCBs residues with high purity.Firstly, a multi-element leaching solution, containing 78% of the total amount of Cu present in the residue together with other metals, was obtained using acidic (HNO3 2 mol/L for 210′ at 50 °C) conditions. In a second step, a bispicolylamine resin was used to recover Cu with high selectivity from the multi-element (59.0% Cu) leaching solution and a final Cu solution with high purity (99.0%) was obtained after eluting, with H2SO4 4 mol/L, the Cu retained in the column.Additionally, the amount of Al (85%) leached from the residue, present in the raffinate, was totally recovered as a solid of Al(OH)3.

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