The recycling of steel scrap gains increasing attention as global decarbonization efforts intensify, driving the development of sustainable alloy design that prioritizes scrap tolerance. A challenge is the presence of tramp elements such as copper (Cu) and tin (Sn), which can significantly influence material properties even at low concentrations. In this study, eight Fe–Cu and Fe–Cu–Sn alloys are investigated to elucidate the effects of chemical composition on solidification microstructure and micromechanical behavior. The results reveal a pronounced grain refinement effect induced by Cu and Sn in as‐cast conditions, reducing grain size from about 130 to 13 μm. Micromechanical testing of boundaries with segregation reveals that: in Fe–Cu alloys, the boundaries are harder than the matrix due to solid solution strengthening by Cu atoms in the ferrite lattice, whereas in Fe–Cu–Sn alloys, the boundaries appeared softer, which is suggestive of the possible formation of (Cu, Sn) precipitates during solidification. These findings advance understanding of the influence of Cu and Sn on microstructure and micromechanical properties of recycled steels. Further elucidating these mechanisms and their dependence on alloying will support the development of steels with extended compositional tolerance, enhancing recyclability and promoting sustainable steel production.

This study examines the potential to enhance the physical and mechanical properties of cast-iron-based composite materials produced by regenerative melting of cast-iron shavings with a nickel-chromium alloy. Calculations show that carbon release intensifies with increased softening rates, accompanied by changes in the absolute mass of the scrap. However, temperatures above 1000°C are undesirable, as particle agglomeration occurs, creating additional processing challenges. Regenerative annealing of cast iron scrap improves its physical and technological characteristics. A notable increase in hardness was observed in “iron-cast iron” composite samples containing 3 % nickel-chromium alloy. In contrast, annealing the scrap at 700°C did not result in any significant improvement in sample strength. Keywords: cast iron composite, regenerative melting, nickel-chromium alloy, cast iron scrap, annealing, hardness, carbon release, mechanical properties

Scrap metal recycling offers significant resource recovery potential due to its rapidly growing volumes while providing financial gains in developing and emerging economies. Hence, the objective of this paper was to carry out a systematic review of the opportunities and best practices of scrap metal recovery and characterization in Aba, Umuahia and Ohafia, South Eastern Nigeria, using appropriate standard methods, including a site-specific/output approach to provide specific details of individual components of scrap metals and the generation trend. The characterization revealed significant mean recoveries of various scrap metals including iron (1026.03± 78.55 tonnes), aluminum (819.36±59.6 tonnes), copper (88.08±7.62 tonnes), brass (143.47± 16.67 tonnes), lead (106.33±8.36 tonnes), nickel (90.61±7.65 tonnes), LCD/LED screen (1.718±1.06 tonnes), printed circuit board (0.926±0.81 tonnes) hard drive (0.56±0.65 tonnes) and other electrical appliances (1.446 ±1.63 tonnes). The highest volume of scrap metal recovered was recorded in February, and the lowest in July, indicating that seasonal cycles influenced the economic performance of its recovery. Despite nonferrous metals accounting for a greater percentage of the recovered scrap metal, wrought iron was the most abundant scrap metal. Scrap characterization and recovery are a sustainable approach to its management and a source of livelihood for the teeming population.

A major issue in industrial production is the generation of post-production wastes that are not biodegradable. The article presents an innovative solution for the management of industrial waste, which includes, among others, metal dust generated during the grinding of castings. The results of research on a concrete composite modified with metallic dust, a by-product from cast iron product manufacturing, were presented. The study analyzed the effect of using metallic dust as a partial replacement for fine aggregate at levels of 10%, 20%, 30%, 40%, and 50% on selected concrete properties. Tests included concrete mix consistency, compressive strength after 28 days and 6 months, density after 28 days of curing, bending strength, abrasion resistance using the Boehme disk method, durability in a salt chamber, and air content in hardened concrete. The research results indicate the possibility of using waste metal dust in concrete composites as a substitute for sand as a fine aggregate. An innovative waste processing solution allows the creation of a product with better abrasion resistance and compressive strength parameters while also having a good impact on the environment.

Abstract Residual elements such as Cu and Sn have been introduced into steel due to increasing usage of steel scrap, which may influence the microstructural evolution during processing. This study investigates the solute drag effect of Cu (0.5 wt pct), Sn (0.3 wt pct) and Nb (0.035 wt pct) on recrystallisation kinetics in low carbon microalloyed steels during hot deformation. Double hit compression tests have been carried out at 1000 °C to 1050 °C and strain rates of 2 s −1 , to measure the solute retardation parameter (SRP). Results reveal that Nb exhibits the strongest individual retardation (SRP ≈ 383), consistent with literature, whilst the SRP has been measured to be 6 for Cu and 86 for Sn. In terms of the synergetic effect, Cu and Nb solute drag effect act additively, but Sn and Nb exhibit a negative synergy, reducing the combined SRP by 36 pct compared to a linear-addition prediction. This has been attributed to Sn having a high diffusivity and binding energy, which may saturate grain boundary vacancies and diminish Nb’s effectiveness. Stress–strain analysis reveals that the Sn addition increases the work hardening rate with increasing strain, unlike Cu and Nb. The observed two distinct solute–dislocation interaction behaviours during deformation further supports the hypothesis that Sn tends to have a stronger affinity to grain boundaries and dislocations at deformation temperatures of 1000 °C and 1050 °C, compared to Nb and Cu addition.

4E optimization in the solar energy storage unit with waste metal chips using taguchi-based grey relational analysis

Volatilization behavior of thallium and valuable metals (lead, zinc and cadmium) in thallium-containing waste during thermal treatment

Process-adapted material characterization for ferrous metal recovery from residues arising in scrap cutting operations.

Preparation of phosphogypsum-based polysulfide and its application in solidified copper-contaminated soil.

RTDRNet-lite: A lightweight real-time detection framework for robotic waste sorting.

Phage display screening for highly specific nickel- and cobalt-binding peptides for bio-recovery of metals.

Poly(butylene adipate-co-terephthalate) (PBAT) wastewater, characterized by high chemical oxygen demand (COD) and acidity, poses significant challenges to anaerobic digestion (AD) due to toxicity and volatile fatty acids (VFAs) accumulation. This study coupled granular activated carbon (GAC) and waste iron scraps (WISs) to synergistically enhance AD performance. Batch experiments demonstrated that, compared with the control, the GAC/WISs group achieved a COD removal efficiency of 53.18% and a methane production of 207.53 ± 5.80 mL/g COD, which were 5.48- and 12.14-fold increases, respectively, while reducing the accumulation of total VFAs by 98.48% (to 15.09 mg/L). Mechanistic analysis revealed that GAC adsorbed inhibitors and enriched methanogens, while WISs buffered pH and promoted direct interspecies electron transfer (DIET) through hydrogenotrophic methanogenesis. Metagenomic sequencing showed shifts in microbial communities, with enrichment of syntrophic bacteria (Syntrophobacter) and functional genes (pta, bcd, and pccA), indicating metabolic reprogramming. This study provided a theoretical foundation and engineering strategy for the anaerobic treatment of PBAT wastewater.

Bacterial metal recovery is regarded as an environmentally friendly alternative to chemical hydrometallurgical waste metal recycling. However, conventional studies are generally conducted under neutral pH conditions, even though typical acidic metal leachate is strongly acidic. Previously, we isolated the bacterial strain Priestia sp. Mn7, which can grow under neutral pH and recover metals (Co, Cu, Li, Mn, and Ni) under pH 1.5. This study aimed to clarify this strain's metal tolerance and recovery mechanisms under pH 1.5 conditions. Metal recovery test was conducted using pH 1.5 solution without the five metal species described above. Enhanced expression of genes related to the sugar ATP binding cassette transporter and increased sugar concentration in metal-abundant solution indicated that the strain expels sugar from the cell as a metal stress response under strongly acidic conditions. Dead cells did not recover metals except for Mn. Additionally, the recovered metals were distributed on the cell surface. These results indicated that the strain recovers tested metals via bioprecipitation related to sugar expulsion. To the best of our knowledge, this is the first study to elucidate the metal tolerance and recovery mechanisms of acid-tolerant bacteria under pH 1.5, further contributing to the understanding and utilization of acid-tolerant bacteria.

Steel is potentially infinitely recyclable, and the ‘green transition’ in this sector (which accounts for 7% of global CO 2 emissions) heavily relies on the dismissal of old polluting blast furnaces in favour of electric arc furnaces (EAFs), which are fed with steel scraps. Steelmaking is considered a strategic capacity for states, for economic but also security and military reasons. At the same time, due to global overcapacity, steelmaking is becoming increasingly less profitable, especially for plants based in high-income countries. The combined pressure of ecological, security and economic challenges makes this scrap-based ‘green’ transition in steelmaking appear both virtuous and rational. Informed by the disarticulations approach combined with the insights of feminist IPE and critical literature on waste, this article argues that the idea of infinite recyclability of steel scraps in fact conceals unequal logics of exclusion and inclusion that operate across material, ecological and human dimensions of the ‘greening’ of the steel industry. The logic of inclusion is manifested in the recycling and downcycling of resources, including human resources, while the logic of exclusion refers to the scrapping of those parts of steel production that are perceived not to have value: from the blast furnaces to the land they sit on; and from steelmaking jobs to the identity and landscapes of steel towns.

This study confirms that scrap metal work has strategic potential in supporting the circular economy and sustainable development in Indonesia. More targeted policy support is needed through empowering business actors, access to financing, and increasing environmental awareness so that this sector can grow productively and sustainably. In Indonesia. The author's goal is to find out the impact of work ethic and work environment in shaping organizational commitment and satisfaction. The population in this study is scrap metal workers. The sample taken was 339 workers. The data analysis technique used is the Structural Equation Modeling (SEM) method. The results of the study show that (1) there is an influence of work ethic on organizational commitment, (2) there is an influence of work ethic on job satisfaction, (3) there is an influence of the work environment on organizational commitment, (4) there is an influence of the work environment on job satisfaction, (5) there is an influence of organizational commitment on job satisfaction.

Hazardous and Toxic Waste (B3) from laboratories, especially those containing heavy metals (Hg and Cr) and several physical factors such as pH, TSS, and color, poses a serious threat to the environment if not managed properly. This study aims to estimate the adsorbent for the development of laboratory-scale wastewater treatment equipment based on the adsorption method using biochar, zeolite, and activated alumina. The research method involves preparing adsorbent materials, testing their effectiveness in reducing the content of heavy metal pollutants, and designing a waste treatment device. The combination of biochar, zeolite, and activated alumina was chosen due to their complementary abilities in removing heavy metal content from B3 waste in the Soil Chemistry laboratory. The treatment results showed significant reductions (p < 0.05) in heavy metal (Hg and Cr) levels in laboratory waste. The optimal combination is a formulation of biochar, zeolite, and activated alumina (1:1:1). Innovations in adsorbent technology for processing heavy metal waste in soil chemistry laboratories can be applied and further developed to create a clean and healthy environment.

Grinding swarf is a hazardous waste generated in hundreds of thousands of tons and currently has limited options for recycling. It is an environmental and economic burden for the manufacturing industry and new recycling processes are necessary for sustainable waste management. Ferric chloride (FeCl3) is an oxidant which can be used to extract metals from steel scrap to produce ferrous chloride (FeCl2) solutions. This was applied for recycling of grinding swarf containing 64% mostly metallic Fe by dissolving it in concentrated FeCl3. Optimization of leaching conditions showed that up to 94% of Fe was recovered as FeCl2 within 1 h of leaching with FeCl3, but that reaction temperature was difficult to control due to highly exothermic reactions. In contrast, classical leaching with hydrochloric acid only recovered 41% Fe from swarf in 2 h and forms large volumes of flammable H2. This improvement in efficiency was attributed to the leaching mechanisms of FeCl3 which are kinetically superior and capable of circumventing lubricant components which otherwise protect the steel surface. These findings contribute to the development of a safe recycling process for valorisation of grinding swarf. Production of iron chloride solutions with applications in water treatment promotes recycling and reduces incineration and landfilling of this waste.

Steel scrap is a recyclable iron-containing resource, and its melting behaviour in an iron–carbon bath has been highlighted in recent years. To reach carbon neutrality, understanding the melting behaviour of steel scrap and utilising more steel scrap are feasible solutions to achieve this goal. This paper aims to summarise previous research on the melting behaviour of steel scrap in an iron–carbon bath, which includes investigating the scrap melting mechanism and the factors that affect scrap melting through thermal simulation, cold model investigation, and numerical simulation. The melting of steel scrap primarily involves the formation and remelting of a solidified layer, as well as the carburisation and rapid melting of the steel scrap. Furthermore, the effect of thermodynamics, kinetics, bath and scrap composition, scrap types and structures on scrap melting is outlined. These findings could provide a theoretical guidance for improving scrap utilisation in steelmaking process.

The steel industry is undergoing a transformative shift toward decarbonisation, necessitating increased reliance on electric arc furnace (EAF)-based production. This transition will significantly increase the demand for steel scrap, requiring strict control over charge quality to maintain steel integrity. Scrap quality is influenced by bulk density and surface-to-volume ratio, which dictates heat transfer efficiency, metallurgical loss, and productivity in EAFs. Pre-treatment processes (e.g. sorting and shredding) modify these parameters hence further affecting furnace performance. Accordingly, the mathematical model developed in this study aims to optimise the bulk density of shredded and hammer milled scrap by balancing two of the main EAF process parameters, namely hourly productivity and metallurgical loss. Optimal bulk density for scrap ranges between 400 to 600 kg/m³, ensuring the best compromise between productivity and metallurgical loss. Model validation through industrial-scale EAF experiments confirms predictive accuracy. Results suggest that continuous charging EAFs or single-charge furnaces with increased volume improve operational efficiency by reducing bucket loading frequency. As the final implication, the proposed model provides critical guidelines for the steel industry to enhance EAF efficiency, reduce energy consumption, and support decarbonisation goals.

Over the past few decades, battery industry and electronic equipment have undergone explosive growth, but the heavy metal waste generated has led to significant global ecological and public health challenges. Currently, increasing evidences have confirmed the detrimental effects of heavy metal exposure on animal reproduction, immunity, and metabolism. However, research focused on the impacts of battery leakage on the gut microbiota remain scarce. Thus, this study aims to investigate the detrimental effects of battery on gut microbiota in chickens. Results revealed that battery exposure can lead to a significant increase in spleen index and a significant decrease in thymus index in chickens. Furthermore, battery exposure can significantly increase serum ALT, AST and MDA levels, and while concurrently reducing levels of GSH-Px and SOD. Battery exposure also cause a significant reduction in the gut microbial alpha diversity, accompanied by significant alterations in taxonomic composition. Bacterial taxonomic analysis indicated that the relative abundances of 1 phyla and 4 genera increased dramatically, while the relative abundance of 3 phylum and 115 genera decreased significantly during battery exposure. In conclusion, this study suggests that battery exposure leads to gut microbial dysbiosis and affect antioxidant ability in chickens. The significant alterations of gut microbiota may represent one of the mechanisms through which battery exerts its intestinal and renal toxicity. Given the context of battery pollutant leakage and inadequate recycling supervision, this study contributes to providing impetus for environmental protection agencies and organizations worldwide to enhance the recycling of battery waste.