Search Results (51)

As a metallurgical solid waste rich in active calcium oxide, magnesium slag (MS) is endowed with significant carbon dioxide sequestration potential due to its inherent properties, providing a feasible path for the simultaneous solution of waste residue disposal and carbon dioxide emission reduction. However, current research has neither clarified the kinetic mechanism (core theoretical support for carbon dioxide sequestration industrialization) nor systematically evaluated the life cycle environmental impacts of MS’s two carbonation routes (direct or indirect leaching carbonation). To address this, this study explores kinetic laws via the single-factor control variable method, and combines life cycle assessment (LCA) to fill the gap, providing key theoretical support for process optimization and engineering promotion. Kinetic results show indirect carbon dioxide sequestration (ICDS) forms an inert silicon-rich layer (core-shrinkage model, mixed control, 28.4 kJ/mol activation energy), while direct carbon dioxide sequestration (DCDS) involves dual-layer formation and pore blockage (mixed control, 14.0 kJ/mol). The ICDS achieves a higher reaction rate of 89%, compared to 63% for the DCDS. In life cycle assessments, DCDS demonstrates outstanding overall environmental sustainability, particularly excelling in carbon dioxide sequestration and acidification control, while ICDS exhibits significant environmental drawbacks (such as high carbon dioxide emissions and ecological toxicity). However, ICDS possesses advantages such as high feedstock utilization and strong synthesis capabilities for high-value-added products. Through targeted optimization, its environmental indicators can be reduced in the future, making it suitable for specific scenarios like high-end calcium carbonate production and resource utilization of low-grade magnesium slag. Full article

Intensive calcination, selection and metallurgical joint comprehensive utilization of solid waste blast furnace gas ash generated by a Chinese iron and steel plant. The main valuable elements in the gas ash are Fe, Pb, Zn, and C, with contents of 22.46%, 3.22%, 10.57%, and 27.02%, respectively. The iron minerals are mainly magnetite and hematite/limonite. Lead exists primarily in the form of lead vanadate and basic lead chloride. Zinc is associated with oxygen, sulfur, and iron in the form of zinc ferrite crystals. The effects of calcination temperature, calcination time, and reducing agent dosage on gasification and reduction indices were investigated. Results showed that using a gasification and reduction calcination–magnetic separation process with weak magnetism, at a calcination temperature of 1150 °C, with 20% anthracite as the reducing agent and a calcination time of 2 h, the volatilization rates of lead and zinc reached 96.70% and 98.26%, respectively. When the roasted ore was ground to a particle size of D₉₀ = 0.085 mm, high-quality iron concentrate with 65.61% iron grade and low lead and zinc contents of 0.08% and 0.17% was obtained, meeting the quality requirements for iron concentrate. The tailings from iron selection can be used as additives in cement and other construction materials. This integrated process combining pyrometallurgy and mineral processing enables the efficient and comprehensive utilization of blast furnace gas dust. Full article

The article presents the results of a study on the production of a complex chromium–manganese–silicon-containing ferroalloy in a large-scale laboratory ore-thermal furnace using man-made waste—chromium-containing aspiration dust obtained during smelting of high-carbon ferrochrome, fines (−5 mm) of iron–manganese ore currently stored in landfills, and finely dispersed coal sludge formed during enrichment. A single-stage technology for the production of a new complex chromium–manganese–silicon-containing ferroalloy by carbothermal reduction is proposed. A metallurgical assessment of the initial charge materials was carried out by the X-ray diffraction (XRD) phase analysis, and metal samples of the obtained ferroalloy were studied by scanning electron microscopy (SEM) in combination with energy dispersive spectroscopy (EDS). The resulting ferroalloy has a complex microstructure with a predominance of carbide and intermetallic phases. A high degree of extraction of chromium (up to 80%), manganese (up to 75%), and silicon (up to 35%) was recorded. The average chemical composition of the obtained ferroalloy, wt.%: Cr—37.41; Mn—17.31; Si—11.84; C—3.81; P—0.14; S—0.02. The slag formed during the smelting of the ferroalloy has satisfactory technological properties: it is characterized by good fluidity, and it actively exits the furnace by gravity. Entanglement of metal kings in the slag is not observed. The results obtained confirm the technological feasibility of the utilization of technogenic raw materials for the production of complex ferroalloys of the FeCrMnSi type. Full article

The challenges faced by the metallurgical industry implicate that actions aimed at reducing negative impacts on the environment are becoming extremely important. This is justified both in the search for economically competitive methods of producing basic construction materials, consistent with the circular economy policy, and in improving the efficiency of metal production technology. An essential aspect of biomass use is the introduction of an energy source that naturally reduces the energy supplied to the reactor, thereby reducing the carbon footprint of the metal produced. In this case, the research undertaken aims to determine the possibility of using a bioreductant that will allow for the reduction or elimination of the fossil raw material, which is coal, thus reducing the costs associated with ETS and ETS II (European Union Emissions Trading System). This paper presents the results of research on the reduction process of oxide metal-bearing raw material, the chemical composition of which is similar to slags from the copper industry. The effects of slag reduction time on the degrees of copper and lead removal were examined. The process was carried out at 1300 °C, with the constant addition of a reducing agent, in the form of crushed pine cones. After processing for 1 h, the copper content in the waste slag was 1.30 wt%, whereas extending the process to 5 h reduced the copper content to 0.15 wt%. For lead, at the exact reduction times, the element’s contents in the slag after processing were 1.92 wt% and 0.79 wt%, respectively. The results of the studied process showed that, in the first stage of the slag reduction process, intensive reduction of copper and lead oxides occurs. Research was also conducted to characterize the biomaterial during the high-temperature process. Results show high degrees of removal for basic metals at the following levels: 99% for Cu and 72% for Pb. The waste slag is characterized by low metal content, which allows for safe storage or use in other sectors of the economy. This type of biomaterial is, therefore, recommended for research in large-scale laboratories or on a semi-industrial scale, particularly in relation to the gas phase formed and its possible impacts on the structural elements of industrial installations. It should be noted that there is a lack of data in the literature on the use of forest biomass in the form of pine cones as an alternative to coke as a reducing agent for use in pyrometallurgical processes. Full article

The limited availability of high-quality ore deposits and the environmental hazards of metallurgical wastes highlight the importance of developing resource-efficient metal recovery technologies. Zinc kiln slag (ZKS), also known as Waelz slag, a by-product material enriched in non-ferrous metals, was processed through oxidative HCl leaching with H₂O₂ as an oxidant. Thermodynamic simulation and laboratory experiments were applied to determine optimal leaching conditions to dissolve copper, zinc, and iron. Optimal leaching efficiency was achieved with consumptions of 0.8 g HCl and 0.1 g H₂O₂ per gram of ZKS, a liquid-to-solid (L/S) ratio of 5 mL/g, a temperature of 70 °C, and a duration of 180 min, which resulted in recoveries of 96.3% Cu, 93.6% Fe, and 76.8% Zn. The solid residue with 43.5 wt.% C is promising for reuse as a reductant material in pyrometallurgical processes. Copper and arsenic were separated from the leachate via cementation with iron powder, achieving recovery rates of 98.9% and 91.2%, respectively. A subsequent two-step iron precipitation produced ferric hydroxide with 52.2 wt.% Fe and low levels of impurities. As a result, the developed novel hydrochloric acid oxidative leaching and metal precipitation route for ZKS recycling provides an efficient and sustainable alternative to conventional treatment methods. Full article

Residual oil (RO) in terrigenous reservoirs formed after waterflooding can exceed 60% of the original oil in place; approximately 70% is trapped at the macro-scale in barriers and lenses, whereas about 30% remains at the micro-scale as film and capillary-held oil. This review aims to synthesize current knowledge of RO formation mechanisms, localization methods and chemical recovery technologies. It analyzes laboratory, numerical and field studies published from 1970 to 2025. The physical and technological factors governing RO distribution are systematized, and the effects of heterogeneities of various types, imperfections in pressure-maintenance (waterflood) systems and contrasts in oil–water properties are demonstrated. Instrumental monitoring techniques—vertical seismic profiling (VSP), well logging (WL), hydrodynamic well testing (WT) and geochemical well testing (GWT)—are discussed alongside indirect analytical approaches such as retrospective production-data analysis and neural-network forecasting. Industrial experience from more than 30,000 selective permeability-reduction operations, which have yielded over 50 Mt of additional oil, is consolidated. The advantages of gel systems of different chemistries are evaluated, and the prospects of employing waste products from agro-industrial, metallurgical and petroleum sectors as reagents are considered. The findings indicate that integrating multi-level neural-network techniques with instrumental monitoring and adaptive selection of chemical formulations is crucial for maximizing RO recovery. Full article

The accelerated industrialization in China has precipitated a dramatic surge in solid waste generation, causing severe land resource depletion and posing substantial environmental contamination risks. Simultaneously, the cement industry has become characterized by the intensive consumption of natural resources and high carbon emissions. This review aims to investigate the current technological advances in utilizing industrial solid waste for cement production, with a focus on promoting resource recycling, phase transformations during hydration, and environmental management. The feasibility of incorporating coal-based solid waste, metallurgical slags, tailings, industrial byproduct gypsum, and municipal solid waste incineration into active mixed material for cement is discussed. This waste is utilized by replacing conventional raw materials or serving as active mixed material due to their content of oxygenated salt minerals and oxide minerals. The results indicate that the formation of hydration products can be increased, the mechanical strength of cement can be improved, and a notable reduction in CO₂ emissions can be achieved through the appropriate selection and proportioning of mineral components in industrial solid waste. Further research is recommended to explore the synergistic effects of multi-waste combinations and to develop economically efficient pretreatment methods, with an emphasis on balancing the strength, durability, and environmental performance of cement. This study provides practical insights into the environmentally friendly and efficient recycling of industrial solid waste and supports the realization of carbon peak and carbon neutrality goals. Full article

The metallurgical industry has been constantly changing over the past decades. On the one hand, there has been the modernization and improvement of production efficiency, and on the other hand, we have seen a reduction in the negative impact on the environment. The possibility of using alternative materials and the circular economy is significant in this area. In the present work, research was carried out to determine the usefulness of biomass in the form of fruit seeds for the recycling processes of metal-bearing raw materials, including slags from copper production processes, which are characterized by a much higher metal content than ores of this metal. The main carbon-bearing material/reducer used in the process is metallurgical coke. The transformation of the European metal industry has been observed in recent years. To carry out the physicochemical characterization of the tested material, a research methodology was adopted using tools to determine the stability of behavior at high temperatures, chemical composition, and volatile components. Thermodynamic analysis was carried out, indicating the theoretical course of reactions of individual system components and thermal effects, allowing a determination of whether the assumed reactions are endothermic or exothermic. The planned research ends with the reduction process in conditions similar to those carried out in industrial conditions. Enforced by the guidelines for reducing CO₂ emissions, it contributes to a significant reduction in the demand for coke. This paper addresses the issue of determining the feasibility of using selected bioreducers, including cherry stones, to verify their suitability in the process of reducing copper oxides. The study used copper slag with a composition similar to slags generated at the copper production stage in a flash furnace. The results obtained in reducing copper content above 98 wt. % indicate the great potential of this type of bioreducer. It should be noted that, unlike conventional fossil fuels, the use of cherry stones to reduce copper slag can be considered an environmentally neutral method of carbon offset. The resulting secondary slag is a waste product that can be stored and disposed of without harmful environmental effects due to its low lead content. An additional advantage is the relatively wide availability of cherry stones. Full article

Amid escalating global climate crises and the urgent imperative to meet the Paris Agreement’s carbon neutrality targets, the steel industry—a leading contributor to global greenhouse gas emissions—confronts unprecedented challenges in driving sustainable industrial transformation through innovative low-carbon steelmaking technologies. This paper examines decarbonization technologies across three stages (source, process, and end-of-pipe) for two dominant steel production routes: the long process (BF-BOF) and the short process (EAF). For the BF-BOF route, carbon reduction at the source stage is achieved through high-proportion pellet charging in the blast furnace and high scrap ratio utilization; at the process stage, carbon control is optimized via bottom-blowing O₂-CO₂-CaO composite injection in the converter; and at the end-of-pipe stage, CO₂ recycling and carbon capture are employed to achieve deep decarbonization. In contrast, the EAF route establishes a low-carbon production system by relying on green and efficient electric arc furnaces and hydrogen-based shaft furnaces. At the source stage, energy consumption is reduced through the use of green electricity and advanced equipment; during the process stage, precision smelting is realized through intelligent control systems; and at the end-of-pipe stage, a closed-loop is achieved by combining cascade waste heat recovery and steel slag resource utilization. Across both process routes, hydrogen-based direct reduction and green power-driven EAF technology demonstrate significant emission reduction potential, providing key technical support for the low-carbon transformation of the steel industry. Comparative analysis of industrial applications reveals varying emission reduction efficiencies, economic viability, and implementation challenges across different technical pathways. The study concludes that deep decarbonization of the steel industry requires coordinated policy incentives, technological innovation, and industrial chain collaboration. Accelerating large-scale adoption of low-carbon metallurgical technologies through these synergistic efforts will drive the global steel sector toward sustainable development goals. This study provides a systematic evaluation of current low-carbon steelmaking technologies and outlines practical implementation strategies, contributing to the industry’s decarbonization efforts. Full article

The environmental impacts of industrial processes have increased the demand for sustainable alternatives in wastewater treatment. Conventional chemical coagulants, though widely used, can generate toxic residues and pose environmental and health risks. Biocoagulants, derived from natural and renewable sources, offer a biodegradable and eco-friendly alternative. This review explores their potential to replace synthetic coagulants by analyzing their origins, mechanisms of action, and applications. A total of 15 studies published between 2020 and 2025 were analyzed, all focused on industrial wastewater. These studies demonstrated that biocoagulants can achieve similar, or the superior, removal of turbidity (>67%), solids (>83%), and heavy metals in effluents from food, textile, metallurgical, and paper industries. While raw materials are often inexpensive, processing costs may increase production expenses. However, life cycle assessments suggest long-term advantages due to reduced sludge and environmental impact. A textile industry case study showed a 25% sludge reduction and improved biodegradability using a plant-based biocoagulant compared to aluminum sulfate. Transforming this waste into inputs for wastewater treatment not only reduces negative impacts from disposal but also promotes integrated environmental management aligned with circular economy and cleaner production principles. The review concludes that biocoagulants constitute a viable and sustainable alternative for industrial wastewater treatment. Full article

The growing environmental impact of copper production necessitates innovative approaches for optimizing metallurgical processes and minimizing waste. This study addresses this challenge by leveraging advanced machine learning (ML) techniques to enhance the efficiency of pyrometallurgical operations such as slag optimization, composition prediction, and waste minimization. Using a combination of real-world and synthetic data, we developed models capable of both forward prediction, estimating slag and matte compositions from ore characteristics, and backward prediction, inferring ore compositions from output characteristics. Five ML algorithms were evaluated, with Gradient Boosting and Support Vector Regression demonstrating superior performance in capturing complex, non-linear relationships. Forward prediction achieved near-perfect accuracy, while backward prediction highlighted the inherent complexity of inverse modeling. This backward-driven strategy proposed in this research aims to determine optimal ore compositions to achieve desired outputs, reducing waste and energy consumption. By integrating ML models with a systematic hyperparameter optimization approach, this work advances the potential for sustainable and precise metallurgical processes. While challenges remain in refining backward predictions, the findings demonstrate the transformative potential of data-driven strategies in industrial metallurgy, paving the way for environmentally sustainable and economically efficient copper production practices. Full article

The backfill binder material is the key to the cost and performance of cemented paste backfill. This study aims to understand the current situation of metal ore backfill binders, identify industry challenges, inspire research ideas, and explore development directions. Current research investigates trends and developments of backfill binders through literature review, experience summary, field research, statistical analysis, and other methods. Firstly, the main backfill binder types are summarized, including cement, metallurgical slag, thermal slag, chemical slag, and tailings binders. Secondly, the research progress regarding reactivity activation, hydration mechanism, harmful ion solidification, energy conservation, and carbon reduction is summarized. Thirdly, three industrial applications of new backfill binders are introduced and summarized. Cement is still the most common, followed by slag powder binder. The cases of steel slag binder and semi-hydrated phosphogypsum backfill have shown significant effects. Solid waste-based backfill binder materials are gradually replacing cement, which is a trend. Finally, further research is discussed, including hydration modeling and simulation, material properties under extreme environments, hardening process control, and technical standards for backfill binders. This work provides a reference and basis for promoting green and efficient paste backfill and sustainable industry development. Full article

A silver-rich lead alloy was obtained through the recycling of two metallurgical wastes: these are lead paste obtained from spent lead–acid batteries and a jarosite residue obtained from the hydrometallurgical production of zinc. Mixtures of both wastes were pyrometallurgically treated with sodium carbonate in a silicon carbide crucible at 1200 °C. The alloy and slag produced were analyzed by atomic absorption spectrometry, X-ray diffraction, and scanning electron microscopy with energy-dispersive spectra. High silver recovery was obtained in a Pb-Ag alloy for a mixture ratio of 30% Na₂CO₃–40% lead paste–30% jarosite, reaching a silver grade of 126 ppm. The slags produced for the highest jarosite content allow the compound formation of Na₂(SO₄) and Na₂Fe(SO₄)₂, which have high sulfur-fixing, avoiding SO₂ release and contributing to the minimization of atmospheric pollution. The novel pyrometallurgical route addresses not only the valorization of precious metals such as silver and lead but also the reduction in accumulated industrial waste. Full article

Due to the emission of hazardous chemicals and heat, the traditional smelting method used to extract critical minerals from ore and mine slag/tailings is considered bad for the environment. An environmentally friendly procedure that can stabilize sulfur emissions from mine waste without endangering the environment is bioleaching. In the present study, sequential oxidative (Oxi) and reductive (Red) bioleaching of acid-pretreated copper smelter slag using iron-oxidizing/reducing Acidithiobacillus ferrooxidans was applied to investigate critical minerals’ recovery for the dissolution of copper smelter slag. In this batch flask experiment, up to 55% Cu was recovered on day 11 during the Oxi stage, which increased to 80% during the Red stage on day 20. A sequential oxidative and reductive bioleaching of an acid-pretreated copper smelter slag at pH (1.8) and 30 °C positively affects the extraction of Cu (80%), Zn (77.1%), and Al (65.3%). In contrast to the aerobic bioleaching experiment, the reduction of Fe³⁺ iron under anaerobic conditions resulted in a more significant release of Fe²⁺ and sulfate, limiting the development of jarosite, surface passivation, and the subsequent loss of metal recovery due to co-precipitation with Fe³⁺. Overall, the Oxi-Red bioleaching process combined with acid pretreatment showed promising results toward creating a method for recovering valuable metals from metallurgical waste that is economical and environmentally beneficial. Full article

Copper production technology is a complex process consisting of many stages. The combination of pyrometallurgical and hydrometallurgical stages, on the one hand, complicates production while, on the other hand, allowing for a relatively selective separation of intermediate or waste materials that can be subjected to the process of recovery of useful components. Materials of this type are characterised by a much higher copper content relative to the ore material. On the other hand, due to the oxide form, reduction processes are used in which coke is mainly applied. Reduction of the unfavourable phenomenon of CO₂ emissions, in this case, can be performed through the use of bioreducers, which are characterised by an inert carbon footprint since the generation of carbon dioxides is the same as its absorption at the stage of vegetation and growth. In this paper, the topic of determining the feasibility of using selected bioreducers, such as peanut shells, to verify their suitability in the process of reducing copper oxides as well as the impact on the working components of the laboratory reactor in which the process is carried out are discussed. In this case, raw materials with a composition similar to the that of slags produced at the copper production stage in a flash furnace were tested for reduction. The results referring to reducing lead and copper contents above 88% Pb and 98% Cu indicate the great potential of this type of bioreducer. An additional advantage is the relatively wide availability of peanut resources. The effects of the copper reduction time on the degree of decopperisation performed with a constant reducer addition at 1300 °C were studied in this paper. Following 1 h of the process, the copper content in the slag was 0.78 wt%, while the longer process duration resulted in a copper fraction of 0.19 wt%. Considering lead, its content was 0.33 wt% after the reduction process. Full article