From extractive waste to sustainable construction materials: Valorization of mine tailings

Abstract. In Europe, the extractive industry generates large waste streams, consisting of billions of tons of tailings, overburden and waste rock each year. Historically, these wastes have been managed through dam storage or landfilling, practices that pose substantial environmental risks, including heavy metal leaching and dam failures. Meanwhile, the construction sector faces increasing pressure to reduce its dependence on primary raw materials, as Portland cement production alone accounts for approximately 8% of global CO₂ emissions. The ValorWaste project was conceptualized to transform extractive waste from an environmental burden into valuable resource for the construction industry. The present study evaluates the potential of extractive waste to be valorised as a source of valuable alternative raw materials for incorporation into sustainable construction materials, with a focus on low-carbon cement and concrete applications. Mine tailings were characterized to assess their suitability as construction materials. Elemental composition was determined by X-ray fluorescence (XRF), while trace heavy metal concentrations were quantified using inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS). Mineralogical phases were identified by X-ray diffraction (XRD), and particle morphology was examined via scanning electron microscopy (SEM). The physico-chemical characterization showed that some of the mine tailings contained more than 80% SiO₂ and low heavy metal concentrations, indicating their suitability for direct use as construction materials. These findings demonstrate a resource recovery approach to mine tailings management through their utilization in the construction sector.

Acknowledgement. This work was supported by the a call is opened for the selection of Research Grant – (tipo de bolsa em inglês) within the framework of Project ValorWaste- “Valorisation and Integration of Extractive Waste Towards the Sustainability of Raw Materials Industry” with the reference ERA-MIN3/0002/2023 with DOI https://doi.org/10.54499/ERA-MIN3/0002/2023) funded by the Fundação para a Ciência e a Tecnologia, I.P., through national funds within the framework of the ERA-NET - European Research Area networks, Cofund in raw materialsand the Ministry of Research, Innovation and Digitization, CNCS/CCCDI - UEFISCDI, project number ERANET-ERAMIN-3-ValorWaste-2, within PNCDI IV.