Journal du génie chimique et de la technologie des procédés
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Studies on Metal (Cu and Sn) Extraction from the Discarded Printed Circuit Board by Using Inorganic Acids as Solvents

Vijayaram R and Dr. Chandramohan K

This Project deals with the experimental results of the leaching of metal like Cu and Sn from Printed Circuit Boards (PCB) from obsolete electronic devices by means of leaching using different combinations of acidic mixtures followed by precipitation. Printed circuit boards were dismantled, cut into small pieces, and fed into a Ball mill. The powder obtained was leached by using the aqueous solutions H₂SO₄, H₂SO₄+HCl, HCl, and HCl+HNO₃. The lowest values for the percentage of metal extraction were obtained with H₂SO₄ while the HCl+HNO₃ mixture exhibited an extraction of Sn and Cu in a maximum percentage. Precipitates were obtained at different pH values by neutralizing the leach liquors using NaOH. The HCl+HNO₃ leach system presented the highest recovery values from the powder feed as well as from the leach liquor. Comparing the results for Sn and Cu extraction after 120 minutes obtained with the various leach systems, 3.0 N HCl+1.0 N HNO₃ exhibited the highest percentage values for simultaneous Sn and Cu extraction (93.3% Sn and 92.7% Cu).