Mining activity is the second biggest producer of waste in the European Union (EU), so to develop processes that allow the reuse of waste and the consequent creation of markets for these secondary raw materials are relevant for a desirable transition to a circular economy. Copper waste such as cakes, tailings, pyrite roasting residues, or slags present very different physical characteristics and hazards. There are two important aspects to consider for the residue of hazardous determination and its reuse: the particle size and the leaching behavior. Also, the reactive or non-reactive property of the waste depends on their origin, which is important for new applications. Based on these parameters (and other specifics for each application), the intention of this paper is to review and study the different applications of copper residues, aiming for new possibilities of cement-based construction materials with added value that allow to economically justify the use of cement.

Hydraulic fracturing drilling technology can cause a high risk of surface spill accidents and thus water contamination. Climate change together with the high water demand and rapid increase in industrial and agricultural activities are valued reasons why we should all care about the availability of water resources and protect them from contamination. Hence, the purpose of this study is to estimate the risk associated with a site contaminated with benzene from oil spillage and its potential impact on groundwater. This study focused on investigating the impact of soil variability and water table depth on groundwater contamination. Temperature-dependent parameters, such as soil water content and the diffusion of pollutants, were considered as key input factors for the HYDRUS 1D numerical model to simulate benzene migration through three types of soil (loamy, sandy clay loam, and silt loam) and evaluate its concentration in the water aquifer. The results indicated that an anticipated increase in earth’s average surface temperature by 4 °C due to climate change could lead to a rise in the level of groundwater pollution in the study area by 0.017 mg/L in loamy soil, 0.00046 mg/L in sandy clay loam soil, and 0.00023 mg/L in silt loam soil. It was found that climate change can reduce the amount of benzene absorbed from 10 to 0.07% in loamy soil, 14 to 0.07% in sandy clay loam soil, and 60 to 53% in silt loam soil. The results showed that the soil properties and solute characteristics that depend on the temperature have a major and important role in determining the level of groundwater pollutants.

The European Union (EU) is heavily reliant on raw materials, some of which pose critical supply challenges. The EU's Critical Raw Materials (CRM) policy, initiated in 2011 and recently reinforced by the 2023 Critical Raw Materials Act, seeks to ensure the sustainable supply of crucial raw materials due to scarcity or economic importance. One such sector significantly affected is photovoltaic (PV) energy production, which faces challenges due to the scarcity of materials like silicon metal, crucial for PV cell manufacturing. Despite efforts to mitigate supply risks, challenges persist, including limited recycling and dependency on imports. This study evaluates annual silicon prices and volatility to assess the business potential of silicon metal production in the EU under current import reliance and 2030 targets. Analysing production trends and applications reveals a concentrated supply chain and diverse industrial uses of silicon metal. Price analysis highlights specific events influencing silicon metal prices, emphasizing its criticality to various economic sectors.

The mining sector is in urgent need of circular economy strategies to manage its historical environmental liabilities. This study investigates the upcycling of mining legacy materials from the Iberian Pyrite Belt (IPB) as sustainable substitutes for natural fine aggregates in cement-based composites. Utilising a functional approach, four distinct waste samples (S1–S4) were used as aggregate replacement (10%, 50%, and 100%) in composites. The experimental campaign focused on the critical nexus between environmental safety and technological performance, evaluating leaching behaviour, water demand, hardened density, and mechanical strength. The results identify a threshold of 10% replacement as optimal, yielding high-performance composites with compressive strengths between 39 and 48 MPa at 28 days. Notably, even at 50% replacement, the mixtures exceeded the 20 MPa structural benchmark (22–37 MPa). Leaching tests confirmed that potentially pollutant elements remained well below European regulatory limits, demonstrating effective contaminant immobilisation. These findings validate a new starting point for valorisation routes for IPB mining legacies, proving that it is technically and environmentally feasible to manufacture composites that meet the basic fundamental industrial standards while promoting resource conservation.

The generation of slag from copper smelting is between 40 and 45 Mt per year. However, the utilisation of this material in large-scale applications remains limited. This study evaluates the combined use of copper slag as a fine natural aggregate substitute (50, 75, and 100%) and natural mordenite-type zeolite as a partial cement replacement (25, 40, and 55%) in the development of sustainable mortars. The samples were characterised using XRF, particle size distribution, and density analysis, and sixteen mixtures were produced. The consistency and water demand in fresh state, the flexural and compressive strength at 7 and 28 days, and the porosity measurements of the hardened mortars were analysed. The results demonstrate that zeolite significantly increases water demand, leading to higher porosity (27–34%) and reduced mechanical strength (14–31 MPa). Conversely, copper slag decreases the water-to-cement ratio and produces denser matrices with the lowest porosity values (8–13%), achieving compressive strengths at 28 days that are higher (53–58 MPa) than the reference mortar (50 MPa). In hybrid mixtures, slag partially mitigates the porosity increase induced by zeolite, revealing a favourable interaction between both materials. Mixtures containing 75–100% copper slag and 25% zeolite (MZ-8 and MZ-9) exhibited balanced porosity (18–21%) and mechanical performance (38–39 MPa), confirming their suitability for mortar applications. The findings demonstrate that the joint incorporation of copper slag and natural zeolite is a viable strategy for producing eco-efficient mortars while reducing clinker and natural aggregate consumption.