Cementation-induced recovery of self-assembled ultrafine copper powders from spent etching solutions of printed circuit boards

• Published in: Powder technology Vol. 159; no. 3; pp. 127 - 134
• Main Authors: Fouad, O.A., Abdel Basir, S.M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 23.11.2005; Elsevier
• Subjects: Adsorption; Applied sciences; Cementation; Chemical engineering; Exact sciences and technology; Miscellaneous; Printed circuit boards; Scrap iron chips; Solid-solid systems; Spent etching solutions; Ultrafine copper powders; Ultrafine copper powders; Spent etching solutions; Scrap iron chips; Printed circuit boards; Cementation; Grain size; Adsorption; Impurity; Morphology; Purity; pH; Spent etching solutions; Printed circuit boards; Scrap iron chips; Powder; Cementation; Ultrafine copper powders; High purity
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2005.08.001

Ultrafine copper powders have been recovered from spent etching solutions of printed circuit boards by cementation on helical-form iron scrap chips. The tested solution is an ammoniacal copper solution containing 135 g/l copper with minor impurities. The influences of contact time, temperature, pH, initial copper concentration and Fe stoichiometry on the yield, purity and grain size and shape of the precipitated copper powders were studied. Ultrafine self-assembled copper nanocubes with high purity of about > 99% was obtained at temperature 25 °C, time 20 min, pH 2, Fe stoichiometry 1 X and initial copper concentration 20 g/l Cu. It was proposed that the precipitation of copper from the solution involved two main processes: (1) adsorption of copper ions on the surface of the iron chips due to the iron oxides present on it and (2) cementation of copper ions onto the metallic iron contained in the chips. Scrap iron chips is seen to be an effective material for copper powder recovery from spent etching solutions in a pure and fine form.