Search Results (285)

This study investigates the impact of critical raw material mining and processing on surface water quality within a representative catchment area, using the Luda Yana River Basin in Southern Bulgaria as a case study. Water quality was evaluated using the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI), based on data collected from five monitoring stations. The analysis focused on key heavy metals, including Cu, Zn, Pb, Cd, Fe, Mn, Ni, and As, reflecting the influence of both active and historical mining activities in the region. Index values were calculated for the period 2008–2024 and revealed considerable temporal variability and pronounced spatial differences in water quality along the river course. This study provides one of the first long-term integrated assessments of heavy-metal-related water quality in a mining-impacted river basin in Bulgaria using the CCME WQI framework and offers new evidence on the cumulative effects of historical and ongoing mining activities on surface waters. The calculated CCME WQI values ranged from very low levels indicating poor conditions to moderate values corresponding to marginal and, occasionally, fair conditions. Overall, the predominant water quality categories were “poor” and “marginal.” The results demonstrate that the waters of the studied river basin remain below the thresholds for “fair” physicochemical status as defined by the European Water Framework Directive (2000/60/EC) and the corresponding Bulgarian legislation, including Regulation No. H-4/2012 on surface water characterization and the 2010 Ordinance on environmental quality standards for priority substances and certain pollutants. The findings highlight the persistent anthropogenic pressure exerted on the river system and emphasize the need for improved water management strategies. The study further underlines the importance of integrating environmental protection measures into the exploitation of critical raw materials in order to balance economic development with the sustainable management of water resources. Full article

Recycling of lithium-ion batteries (LIBs) remains challenging due to high energy requirements, losses of key elements like lithium, and the heterogeneity of waste streams arising from different cathode chemistries. This study evaluates multiple recycling methods for LIBs black mass (BM), to recover critical raw materials and other valuable components. Three types of BM including nickel–manganese–cobalt (NMC), lithium iron phosphate (LFP) and a heterogeneous mixture of cell phones and laptops (HL; German: Handy/Laptops), were treated using froth flotation, pyrometallurgy, and biohydrometallurgy and their respective recovery efficiencies were assessed. The flotation results revealed that the HL sample had the lowest mis-recovery of non-ferrous metals into the froth product (around 10%), leading to further flotation only for HL. During screening, 94–99% of iron, phosphorus, and carbon in LFP-type BM were recovered in the fine fraction (<45 µm), while 92–99% of lithium, cobalt, manganese, nickel, and carbon in NMC-type BM were recovered in the same fraction. During precipitation, 99% of iron and 100% of phosphorus were recovered from LFP bioleachates at pH 3, while ~97–100% of dissolved cobalt, manganese, and nickel were recovered from NMC bioleachates. These findings confirm that no single recycling method is optimal for all battery chemistries. Full article

Critical raw materials (CRMs) sit at the intersection of industrial strategy, climate policy, sustainable development, and geopolitics. This paper reviews how the concept has evolved since the 1939 US Strategic and Critical Materials Stock Piling Act, tracing the gradual addition of economic, energy, technological, environmental, and sustainability criteria to the original military framing. It then compares the methodologies developed by the European Union and the United States over the last fifteen years. The EU has published five consecutive lists between 2010 and 2023; the US has produced parallel frameworks through the U.S. Geological Survey and the Department of Energy, each weighing supply risk, economic importance, environmental impact, and clean energy relevance differently. The 2023 EU list is examined in detail, including the addition of copper and nickel on strategic rather than quantitative grounds. Convergences and divergences across the three frameworks are discussed, alongside their alignment with the United Nations Sustainable Development Goals—particularly SDG 7, SDG 9, SDG 12, and SDG 13—and the progressive integration of circular economy targets, recycling indicators, and environmental impact considerations into criticality assessment. The analysis shows that sustainability has become a structural axis of CRM policy rather than a peripheral concern. The review provides the methodological background for a companion paper that applies the EU methodology to resource-rich Latin American countries (Chile, Brazil, and Peru). Full article

The environmental management of highly saline coal mine wastewater presents a critical challenge for European mining regions, particularly under the constraints of the EU Water Framework Directive. This study presents a cradle-to-grave life cycle assessment of a novel zero liquid discharge (ZLD) system developed under the EU-funded LIFE Brine-Mining project and deployed at the Ziemowit mine in Poland. The system was designed to treat coal mine brine (TDS ~80 g/L) and recover valuable resources, including high-purity water, sodium chloride, magnesium hydroxide, calcium carbonate, and calcium sulphate. The assessment was conducted in accordance with EN 15804 using the Environmental Footprint v3.1 methodology, ecoinvent v3.10, and a functional unit of 1 m³ of saline wastewater inflow, covering all life cycle stages from raw material extraction to end-of-life and resource recovery (Module D). The results indicate a fossil-based global warming potential of 73.86 kg CO₂ eq. per functional unit, with 66% attributed to operational electricity consumption (module B6, 44 kWh/m³) and 29% to auxiliary chemical consumption (module B1). Three key environmental hotspots were identified: module B1 dominates ozone depletion potential (67%), module B6 dominates acidification potential (66%), and raw material extraction (module A1) dominates abiotic depletion of minerals and metals (43%). Resource recovery credits (Module D) offset 11.80 kg CO₂ eq. of GWP-fossil, cause the ADP-minerals and metals indicator to become net negative, and reduce the water deprivation potential by approximately 50%. A sensitivity analysis confirmed that results are robust to ±10% variations in wastewater inflow, with GWP-total varying within a narrow −0.5% to +0.6% range once the volume-proportional nature of chemical and electricity consumption is correctly accounted for. These findings provide a quantitative sustainability baseline for the scale-up and replication of integrated ZLD technologies in the European mining sector, demonstrating that circular brine treatment can simultaneously address regulatory water quality targets, reduce primary resource consumption, and deliver measurable environmental credits aligned with EU circular economy and sustainable development objectives. Full article

Growing demand for more sustainable packaging has increased interest in bio-based adhesives as alternatives to conventional fossil-derived systems. Among renewable raw materials, lignin is particularly attractive because of its aromatic structure, phenolic functionality, and availability as a side stream of pulp, paper, and biorefinery processes. This review critically examines the potential of lignin-based adhesives for packaging applications. Selected polysaccharide-, protein-, vegetable-oil-, and tannin-based systems are briefly discussed as comparative references, while the main focus is placed on the properties of kraft lignin, lignosulfonates, organosolv lignin, and soda lignin. Their structural differences, adhesive behaviour, and suitability for chemical modification through hydroxymethylation, phenolation, demethylation, depolymerization, oxidation, and epoxidation are evaluated. Because most lignin-adhesive research concerns wood bonding, the transferability of these findings to paper, paperboard, labels, coatings, films, and hot-melt packaging adhesives is critically assessed. Direct evidence for packaging applications remains limited, although existing studies demonstrate promising opportunities for paper bonding, pressure-sensitive systems, and paperboard hot-melt adhesives. Key challenges include lignin heterogeneity, processing complexity, moisture resistance, colour, food-contact safety, scalability, and compatibility with recycling. Full article

Operational risk assessment in complex industrial systems like mineral processing plants is hindered by inherent uncertainty and incomplete information. This study presents an integrated grey system theory-based framework to address this challenge. Combining Grey Multi-Criteria Decision-Making (GST-MCDM) and Grey Relational Analysis (GRA), the methodology enables a systemic analysis that prioritizes risks, quantifies interdependencies, and measures cumulative burden across four key objectives: time, cost, quality, and safety. Applied to a case study at the Gohar Zamin iron ore processing plant (Iran), the model analyzed 26 operational risks, classifying them into Critical (8 risks), Significant (9), and Controllable (9) tiers. Electrical power shortage (RPS: 0.19) and raw material supply delay (RPS: 0.21) were identified as the most critical risks. The analysis quantified that the safety objective bears the highest cumulative risk burden at 32%, primarily due to human factor vulnerabilities, while cyber-physical threats ranked among the top 8 critical risks. Strong interdependencies were revealed, notably a quality cascade (relational grade: 0.84) between poor consumable materials and final product failure. Sensitivity analysis confirmed high model robustness (Spearman’s p = 0.91). The framework provides managers with an actionable tool for strategic, cluster-based mitigation and evidence-based resource allocation, emphasizing investment in human capital as a core risk reduction strategy. This research contributes a replicable, quantitative methodology for enhancing operational resilience under uncertainty in capital-intensive industries. Full article

Financial statement fraud inflicts large and recurring losses on capital markets, yet the dominant detection paradigm still relies on single, black-box classifiers (e.g., RUSBoost) trained on structured accounting ratios alone. Two limitations follow: (i) the rich, unstructured Management Discussion and Analysis (MD&A) narrative of the 10-K filing is discarded, and (ii) the resulting scores are difficult for auditors to trust because they carry no transparent, standards-aligned rationale. Recent large language model (LLM) systems have shown that multi-agent collaboration is more robust than a single LLM for anomaly detection, but no study has systematically transferred this paradigm to listed-company statement fraud. We propose FraudDebate-Agent, a four-role multi-agent system in which a Quantitative Analyst agent scores 28 raw accounting items and 14 ratios with gradient-boosted and tabular attention models, a Narrative Auditor agent quantifies tone, linguistic uncertainty, and year-over-year textual novelty of the MD&A with FinBERT, and an Industry Peer agent uses retrieval-augmented generation to measure industry-relative anomaly. A Critic–Debate agent then orchestrates a pair-wise Evidence-based Multi-Agent Debate (EMAD) that reconciles disagreement across modalities and arbitrates a reconciled fraud-risk assessment, which is aggregated over a tri-modal evidence graph. Our contributions are as follows: (1) the first use of an evidence-grounded debate mechanism for accounting fraud, which materially reduces LLM hallucination; (2) a numerical–textual–peer evidence graph that fuses heterogeneous signals; and (3) an explainable report aligned with the PCAOB AS 2401 fraud-risk taxonomy. On AAER-labelled firm-years linked across a SEC financial dataset and EDGAR-CORPUS, FraudDebate-Agent improves the area under the ROC curve and the rare-event ranking metric NDCG@k over the strongest single-modality and single-LLM baselines while producing substantially more faithful explanations. We frame the system as a fraud-risk screening and risk-ranking tool for AAER-labelled misstatement risk rather than a determination of fraudulent intent. We report results over multiple seeds to reflect real-world stochasticity and discuss limitations and cross-domain applications. Full article

Ukraine’s energy strategy under martial law necessitates decentralized local energy systems to counter electricity shortages and systemic infrastructure failures. The study develops and validates an optimization model for designing the architecture of decentralized “energy islands” based on circular bioenergy models for agricultural waste use. Empirical verification was conducted using data from the Vinnytsia region in Ukraine. The model accounts for a multi-level structure that separates micro/small generation (0.1–2.0 MW) from medium generation (1–20 MW) based on the logistical radius for raw material collection. The model incorporated the Value of Lost Load (VLL), enabling the monetization of avoided socio-economic losses from energy shortages. In addition, the coefficient of energy island sustainability (I_sred) was introduced to quantitatively assess the effectiveness of investments in terms of replacing external resources. The modeling revealed the nonlinear nature of the total cost function, enabling us to determine an optimal energy-autonomy range of 40% to 50% for communities. At this threshold, the total construction and logistics costs are minimized. The potential socio-economic losses from blackouts are effectively mitigated, as confirmed by the calculated sustainability coefficient (I_sred), which ranges from 0.78 to 0.94 across the studied communities. The resource potential assessment confirms that the region’s total potential is approaching 30 million tons of oil equivalent, driven by solid biofuels, agricultural residues, and energy crops (miscanthus, switchgrass). The classification of biomass supply chains shows that exceeding the transportation radius by more than 70 km at the meso level, or deviating from the optimal logistics lever by 20%, reduces the profitability of projects below the critical limit of 15%, which justifies strict localization within raw-material clusters. This enables local communities to eliminate natural gas consumption, reduce energy supply operating costs by 15%, and ensure the autonomous and stable operation of critical infrastructure facilities during prolonged disruptions to the national power grid. Full article

The growing demand for electric traction batteries, together with their high content of Critical Raw Materials (CRMs), necessitates comprehensive life cycle environmental assessments. Limited attention in the literature has been devoted to explicitly disentangling the role of individual CRMs in shaping both environmental burdens and potential end-of-life benefits. This study presents a “cradle-to-grave” life cycle assessment (LCA) of a Lithium Iron Phosphate battery for electric vehicle applications, aiming to identify the contributions of individual life cycle phases and quantify the role of CRMs. The life cycle inventory was developed using data from the literature and the Ecoinvent database, with impacts assessed using the ReCiPe 2016 midpoint hierarchist (H) method. LCA results indicate that the material manufacturing phase dominates most impact categories. A gravity analysis demonstrates that a limited set of CRMs (aluminium, copper, and lithium) structurally governs both environmental burdens and recycling benefits. Monte Carlo analysis indicates low uncertainty for most impact categories. A first sensitivity analysis reveals that improvements in round-trip efficiency exert the strongest influence on environmental performance. A second sensitivity analysis assesses the effect of different energy mixes used to model electricity consumption during the use phase. Full article

Circularity in the aluminium manufacturing and use industries has attracted increasing attention in recent years. This is partly due to the criticality of the raw material and the drive for a more sustainable, greener society through the EU Green Deal and subsequent legislation/frameworks. Several stakeholders regard post-consumer scrap (PCS) as a panacea for this transition to circularity. Obtaining an appropriate, recycling-friendly post-consumer scrap alloy for a product is challenging, thereby intensifying competition in the PCS alloy market. Furthermore, manufacturers in the aluminium industry must conduct accurate and transparent assessments of their products. Life Cycle Assessment is the primary method used today. While several modelling approaches exist within LCA, the EU recommends using either the product environmental footprint (PEF) (50:50) or the Circular Footprint Formula (CFF) approach. This paper highlights the limitations of these modelling approaches and compares them with the net-scrap approach for LCA of high-voltage aluminium cables. The strength of the net-scrap approach lies in its robustness, particularly in demand-heavy PCS markets. It promotes the use of recycled inputs and end-of-life recyclability and allows for the inclusion of metal quality parameters. These are key levers for achieving high circularity (i.e., over 70%) in open-loop recycling of aluminium alloys. Full article

Carnot batteries (CBs) offer an appealing alternative to saturated pumped-hydro facilities and electrochemical batteries dependent on critical raw materials. A concept recently highlighted in the literature is that of coupled CBs, in which the discharge cycle of a CB interacts directly with the power cycle of a thermal power plant. Such configurations show promising gains in performance, cost, and responsiveness. However, their dynamic behavior remains insufficiently characterised, restricting assessment of the grid services they could realistically deliver. This work examines an innovative architecture in which a nuclear Rankine cycle is coupled to a CB to enhance operational flexibility. Following the preliminary system sizing, a detailed numerical analysis is performed using the CATHARE-3 thermal–hydraulic code to characterize the overall steady-state performance and transient behavior during CB discharge. The results show that the high-pressure turbine acts as an effective filter, absorbing most disturbances introduced by the CB. A refined breakdown of inertial contributions within both the Rankine cycle and the CB enables the identification of the most sensitive components. Finally, under these preliminary sizing assumptions, the coupled system exhibits high performance and would be capable of meeting the primary frequency control requirements during discharge operation, suggesting that coupled CBs constitutes a promising solution for providing fast frequency-regulation services to the electrical grid. Full article

Malodorous gases such as ammonia (NH₃) and hydrogen sulfide (H₂S) emitted from pig intestines and excrement have become critical environmental bottlenecks restricting the green transformation of the swine industry. Therefore, identifying sustainable protein feed alternatives with odor-reducing potential has become increasingly important. This study evaluated the effects of replacing soybean meal with four distiller’s grains-derived protein raw materials (DGPRMs), including Baijiu DDGS, Sorghum DDGS, Corn DDGS, and Cassava DDGS, using an in vitro fermentation system simulating the intestinal environment of six fattening pigs. After 24 h of fermentation, odor-related gas production, short-chain fatty acid (SCFA) concentrations, and microbial community composition were analyzed to assess the odor-mitigation potential of these alternative protein sources. Results demonstrated that Baijiu distiller’s grains, sorghum distiller’s grains, and corn distiller’s grains significantly reduced the yields of NH₃ and H₂S under the in vitro fermentation system (p < 0.05). Meanwhile, they reshaped the intestinal microbial community structure by inhibiting the growth and reproduction of odor-producing genera (e.g., Ligilactobacillus) and promoting the enrichment of beneficial genera (e.g., Limosilactobacillus) that were significantly negatively correlated with malodor indicators. Notably, among all tested DGPRMs, Baijiu DDGS exhibited the strongest odor-reducing effect, markedly decreasing NH₃, H₂S, and volatile sulfur compounds while enriching beneficial bacterial taxa associated with reduced odor generation. These findings suggest that selected DGPRMs, particularly Baijiu DDGS, may serve as promising alternative protein ingredients for mitigating odor emissions in pig production systems. Full article

With the Green Deal and the Circular Economy Action Plan, the European Union aims to replace half of the fossil-based raw materials in plastics with sustainable alternatives by 2030. In the plastic pipe industry, the use of post-consumer recyclates (PCRs) remains very limited due to reduced material quality, economic hurdles, limited availability, non-specific classification requirements, and a lack of testing standards. This paper presents two interconnected contributions to the quality-assured use of PCR for buried utility infrastructure made from Polyethylene (PE), Polypropylene (PP), and unplasticized Polyvinyl Chloride (PVC-U). First, a methodological framework, based on EN 13476, defines suitability as the intersection of material classification and application-specific requirements profile. A review of the current regulatory and technical situation reveals a systemic discrepancy: requirements profiles are oriented toward virgin material, while the scope of classification for PCR remains insufficiently defined. As a result, PCR is either used without adequate suitability assessment or blended with fillers, thereby limiting recyclability. Secondly, the review focuses on additive strategies, including restabilization, compatibilization, chain modification, and recyclate-compatible functional additives. These strategies are among the main technical solutions for closing the gap between PCR properties and the product’s requirements, reducing filler dependency, and enabling the long-term use of PCR in safety-critical applications. Full article

This study presents a cradle-to-grave Life-Cycle Assessment of a multifunctional building-integrated photovoltaic (BIPV) skylight system combining a recycled aluminum frame, double-glazing unit, semi-transparent cadmium telluride (CdTe) photovoltaic glass, and an organic phase change material (PCM) for passive thermal regulation. Assessed over a 30-year service life in accordance with EN 15804+A2 using One Click LCA, the system is evaluated across 13 environmental impact categories for a declared unit of 0.72 m². Results show that materials production is the dominant environmental driver across all categories, contributing 72.0% of total GWP (78.00 kg CO₂-eq). Component replacement is the second contributor with 9.8% of GWP. End-of-life burdens account for 7.7% of cradle-to-grave GWP. When Module D credits are included, the system achieves an indicative net GWP balance of −808.34 kg CO₂-eq, that is conditional on a static Romanian grid-mix assumption; under progressive grid decarbonization this benefit is reduced, so the figure should be read as scenario-dependent potential rather than an immutable property of the product. Abiotic depletion of mineral elements is the only category where Module D does not fully offset system burdens, highlighting the relevance of critical raw material considerations for CdTe technologies. These findings demonstrate that BIPV depend on low-impact manufacturing and underscore the importance of multi-indicator LCA as the appropriate evaluation framework for integrated energy-generating building products. Full article

Biobased wood adhesives are essential to reducing the dependence of wood-based panels on petrochemical and formaldehyde-emitting resins. This review critically synthesizes recent progress in lignin-, tannin-, starch-, furan/HMF-, organic acid-, and soy protein-based adhesive systems, with emphasis on chemical reactivity, curing mechanisms, water resistance, processability, and industrial relevance. The discussion distinguishes laboratory performance from industrial feasibility by considering specific press time, solids content, viscosity, raw material variability, emissions, cost, life-cycle performance, and compatibility with particleboard, medium-density fibreboard, plywood, and related engineered wood products. Lignin and tannins are highlighted as the most chemically compatible phenolic platforms, starch and soy systems as abundant but moisture-sensitive binders requiring targeted crosslinking, HMF and furan derivatives as promising aldehyde-type formaldehyde-free crosslinkers, and citric acid systems as attractive polyester-forming binders with pressing-temperature limitations. The review concludes that near-term adoption will most likely proceed through hybrid and partially biobased systems, whereas fully biobased adhesives require faster curing, standardized feedstocks, pilot-scale validation, and transparent techno-economic and life-cycle assessment. Full article