Synthesis of copper nanoparticles from refractory sulfides using a semi-industrial mechanochemical approach

• Published in: Advanced powder technology : the international journal of the Society of Powder Technology, Japan Vol. 31; no. 2; pp. 782 - 791
• Main Authors: Baláž, Matej, Tešinský, Matej, Marquardt, Julien, Škrobian, Milan, Daneu, Nina, Rajňák, Michal, Baláž, Peter
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2020
• Subjects: Copper nanoparticles; Copper sulfides; Magnetometry; Mechanochemistry; Oxidation; Oxidation; Magnetometry; Copper sulfides; Mechanochemistry; Copper nanoparticles
• ISSN: 0921-8831; 1568-5527
• DOI: 10.1016/j.apt.2019.11.032

[Display omitted] •Copper was successfully prepared by mechanochemical reduction of CuS and Cu2S.•Mechanochemical reduction of CuS is reported for the first time.•The experiments were performed on a semi-industrial scale.•Magnetometry was used to evaluate the kinetics of the processes.•Cu2S was reduced more easily than CuS. The large-scale mechanochemical reduction of binary sulfides chalcocite (Cu2S) and covellite (CuS) by elemental iron was investigated in this work. The reduction of Cu2S was almost complete after 360 min of milling, whereas in the case of CuS, a significant amount of non-reacted elemental iron could still be identified after 480 min. Upon application of more effective laboratory-scale planetary ball milling, it was possible to reach almost complete reduction of CuS. Longer milling leads to the formation of ternary sulfides and oxidation product, namely cuprospinel CuFe2O4. The rate constant calculated from the magnetometry measurements using a diffusion model for Cu2S and CuS reduction by iron in a large-scale mill is 0.056 min−0.5 and 0.037 min−0.5, respectively, whereas for the CuS reduction in a laboratory-scale mill, it is 0.1477 min−1. The nanocrystalline character of the samples was confirmed by TEM and XRD, as the produced Cu exhibited sizes up to 16 nm in all cases. The process can be easily scaled up and thus copper can be obtained much easier from refractory minerals than in traditional metallurgical approaches.