The extraction of copper and precious metals from used Printed Circuit Boards (PCBs)
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Date
2016-06
Authors
Siti Norazura Mohamad Noor
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Abstract
This research work presents the extraction of the copper and precious metals (gold and silver) from used printed circuit boards (PCBs). The extraction is involved two-step of leaching process which is sulfuric acid leaching and thiourea leaching. At the first stage, the sulfuric acid leaching is used to extract the copper from the PCBs samples. Then the sample residue from first leaching is leach by acidic thiourea to extract gold and silver. From the analysis result data, the 40% copper content from the sample with the particle size -75μm was digested by using sulfuric acid leaching methods in the presence of H2O2 as an oxidizing agent. For the sample with particle size -300 μm + 200 μm and -200 μm +75μm, the copper content that been digested in sulfuric acid leaching was 2846 ppm and 9030 ppm respectively. The results show that the sample with -75μm is the most efficient size to been used in copper recovery by using sulfuric acid leaching methods. Then the solid residue from the sulfuric acid leaching was dissolved by using acidic thiourea leaching in the presence of ferric iron as an oxidizing agent. There is undervalue of the recovery of gold and silver due to loss that occurs at mechanical processing before the leaching process being done.