Recovery of Non-Ferrous (Cu & Ni) and Precious (Au) Metals from Waste Random Access Memory (RAM).

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Title: Recovery of Non-Ferrous (Cu & Ni) and Precious (Au) Metals from Waste Random Access Memory (RAM).
Authors: Dinkar, Om Shankar1,2 (AUTHOR), Rani, Karina1 (AUTHOR), Parween, Rukshana1,2 (AUTHOR), Panda, Rekha1 (AUTHOR), Sharma, Ankur1 (AUTHOR), Aditi, Apurva1 (AUTHOR), Ambade, Balram2 (AUTHOR), Jha, Manis Kumar1 (AUTHOR) mkjha@nml.res.in
Source: Mineral Processing & Extractive Metallurgy Review. May2026, Vol. 47 Issue 3, p354-366. 13p.
Subject Terms: *Leaching, *Solvent extraction, *Copper, *Gold, *Nickel, *Physisorption
Abstract: Random access memory (RAM) of printed circuit boards (PCBs) is an integral component of most electronic devices. It is one of the vital electronic component that poses significant environmental challenges when discarded but economically significant as it contains non-ferrous and precious metals. The objective of the present work proposes a promising hydrometallurgical process flow sheet to recover copper (Cu), nickel (Ni) and gold (Au) metals from RAM PCBs using mechanical pre-treatment with selective leaching followed by solvent extraction and adsorption techniques. Leaching parameters were optimized for maximum dissolution and extraction of base metals. More than 99% leaching of Cu and Ni were achieved selectively using 1 M H₂SO₄ and 10% HNO₃ leaving Au in residue. Leaching kinetics was found to fit well with the shrinking core models, respectively. These models detailed an appropriate results based on the relative velocity between both solid and liquid properties during leaching steps. Notably, activation energies were determined to be 3.535 kJ/mol for Cu and 2.628 kJ/mol for Ni. Furthermore, four-stage counter-current extraction employing 40% LIX 84-IC at pH 2.5 having O/A ratio of 1/1 resulted in more than 99% copper extraction, with negligible Ni co-extraction leaving nickel in the raffinate. Selective leaching of the leached residue followed by charcoal adsorption and fusion at high temperature was investigated to achieve gold (Au) recovery above 99%. This hydrometallurgical scalability suggests that these processes can be adapted for larger operations; pilot trials, which will help, refine the process and assess its feasibility in a real world, industrial scenario. [ABSTRACT FROM AUTHOR]
Database: Energy & Power Source
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Abstract:Random access memory (RAM) of printed circuit boards (PCBs) is an integral component of most electronic devices. It is one of the vital electronic component that poses significant environmental challenges when discarded but economically significant as it contains non-ferrous and precious metals. The objective of the present work proposes a promising hydrometallurgical process flow sheet to recover copper (Cu), nickel (Ni) and gold (Au) metals from RAM PCBs using mechanical pre-treatment with selective leaching followed by solvent extraction and adsorption techniques. Leaching parameters were optimized for maximum dissolution and extraction of base metals. More than 99% leaching of Cu and Ni were achieved selectively using 1 M H₂SO₄ and 10% HNO₃ leaving Au in residue. Leaching kinetics was found to fit well with the shrinking core models, respectively. These models detailed an appropriate results based on the relative velocity between both solid and liquid properties during leaching steps. Notably, activation energies were determined to be 3.535 kJ/mol for Cu and 2.628 kJ/mol for Ni. Furthermore, four-stage counter-current extraction employing 40% LIX 84-IC at pH 2.5 having O/A ratio of 1/1 resulted in more than 99% copper extraction, with negligible Ni co-extraction leaving nickel in the raffinate. Selective leaching of the leached residue followed by charcoal adsorption and fusion at high temperature was investigated to achieve gold (Au) recovery above 99%. This hydrometallurgical scalability suggests that these processes can be adapted for larger operations; pilot trials, which will help, refine the process and assess its feasibility in a real world, industrial scenario. [ABSTRACT FROM AUTHOR]
ISSN:08827508
DOI:10.1080/08827508.2025.2496515