SELECTIVE LEACHING OF CO AND W FROM HARDMETAL WASTE USING LACTIC ACID ACROSS A WIDE COMPOSITIONAL RANGE
- Martina Cera - Department of Civil and Environmental Engineering and Architecture (DICAAR), University of Cagliari, Italy
- Gian Pietro De Gaudenzi - OMCD TEK HUB, Italy
- Axel Bjerke - OMCD TEK HUB, Italy
- Giorgia De Gioannis - Department of Civil and Environmental Engineering and Architecture (DICAAR), University of Cagliari, Italy - Environmental Geology and Geoengineering, Institute of the National Research Council (IGAG-CNR), Italy
- Fabiano Asunis - Department of Civil and Environmental Engineering and Architecture (DICAAR), University of Cagliari, Italy
- Aldo Muntoni - Department of Civil and Environmental Engineering and Architecture (DICAAR), University of Cagliari, Italy - Environmental Geology and Geoengineering, Institute of the National Research Council (IGAG-CNR), Italy
- Angela Serpe - Department of Civil and Environmental Engineering and Architecture (DICAAR), University of Cagliari, Italy - Environmental Geology and Geoengineering, Institute of the National Research Council (IGAG-CNR), Italy
- Available online in Detritus - In Press
- Pages
Released under All rights reserved
Copyright: © 2026 CISA Publisher
Abstract
The recovery of Critical Raw Materials (CRMs) is a strategic priority for the metallurgical industry. Hardmetal (HM, WC–Co) production is particularly vulnerable to tungsten (W) and cobalt (Co) supply shortages and price volatility, as these elements constitute its primary feedstocks. This study investigates valorization strategies for HM waste through a combined thermal–chemical approach. Oxidized powders (WO₃/CoWO₄) obtained from WC–Co scraps by thermal oxidation were subjected to leaching using lactic acid solutions across a wide range of solution compositions, with particular focus on the dissolution behavior of W and Co. A Co(II) speciation model based on independent literature thermodynamic data, together with dedicated experiments comparing different acid counter-ions (Cl⁻ vs NO₃⁻) and ionic-strengths, showed that solution composition beyond pH alone significantly affects Co dissolution and Co/W selectivity. The systematic evaluation of leaching performance across pH and solution composition provides key insights into metal selectivity and process optimization. The results contribute to the development of a smart and sustainable recycling strategy for efficient W and Co recovery from industrial HM waste streams.Keywords
Editorial History
- Received: 29 Jun 2026
- Revised: 28 Sep 2026
- Accepted: 05 Oct 2026
- Available online: 12 Nov 2026
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