Pyrite concentration and associated polymetallic minerals from the Iberian Pyrite Belt through the multi-gravity separator

Abstract

Waste deposits from the Iberian Pyrite Belt that are rich in pyrite are a valuable secondary resource for getting back sulphide minerals and important metals that go with them. This study assessed the efficacy of a Multi-Gravity Separator (MGS) in concentrating pyrite and related polymetallic minerals from sulphide waste material sourced from the Alonso mining district (Huelva, Spain). Bench-scale MGS tests were done on two particle size fractions (-500 µm and -50 µm) to see how the speed of the drum rotation, the angle of the tilt, and the flow rate of the wash water affected the separation efficiency. Mineral Liberation Analysis (MLA) showed that both size fractions had about 65.8 wt% pyrite, but the -50 µm fraction was much more liberated. Under the best operating conditions, the MGS was able to recover about 58% of the pyrite from the -500 µm fraction and about 64% from the -50 µm fraction. The mass recoveries were about 38% and 42%, respectively. There was also a better recovery of related metals like Co, Cu, Zn, and Mn, especially for the finer fraction. This shows the improvement of the liberation and stratification behaviour. The results show that MGS is a good way to pre-concentrate fine-grained pyrite-rich waste. The performance is heavily influenced by the size distribution of the particles and the operating parameters. These results suggest that improvements in gravity separation may offer a long-term pathway for the recycling of sulphide mine waste within a circular economy.

This work was supported by the METALLICO (GAN 101091682) EU Project and by the Upcycling project (PID2023-147160OB-C21), financed by the Spanish Research Agency (AEI). This work is part of the María de Maeztu Unit of Excellence Programme CEX2023-001300-M funded by MICIU/AEI/10.13039/501100011033 and the Catalan Government through the R2EM group (2021-SGR-GRC-00596). Support for the research of J.L. Cortina was also received through the “ICREA Academia” recognition for excellence in research funded by the Generalitat de Catalunya. Finally, M. Sevilla and A. B. Hernandez from Tharsis Mining S.L. (Huelva, Spain) are acknowledged for mineral samples selection, collection and supply as well for their helpful discussions.

Peer Reviewed

Postprint (published version)