Recycling Of Scrap Research Articles

APPLICATION OF A GAS-SOLID FLUIDISED BED SEPARATOR FOR ALUMINIUM-COPPER SCRAP RECYCLING

The EUbs circular economy concept necessitates the recycling of material streams used once or multiple times into the productionb consumption cycle again and again. The commonly known problem b that the number of recycling cycles of plastics is limited drives the economy towards metal usage again, because metal recycling cycles are limitless. Therefore, the efficient and economic separation of mixed aluminium and copper scraps in the 30b100 mm particle size range is an important issue for our society. In this study fundamental and applied research was carried out for the application of a gas-solid fluidised bed separator for aluminium-copper scrap recycling. A laboratory scale aero-suspension dense media separator was developed. Fundamental fluidisation experiments were carried out with this device and a powder rheometer. Afterwards pilot-scale and later industrial-scale separators were designed and built. The results indicate that the well-known Ergun fluidisation model can be the basis of a new process engineering design method for sizing dry fluidised bed separators.

Efficient purification of scrap 1060 aluminum alloys contaminated with Fe and Si by super-gravity separation

1060 aluminum alloy has been used in high-volume commercial applications and correspondingly the mass of its downgraded recycling after contamination is huge, which is primarily due to the gradual accumulation of impurity elements such as Fe and Si. The separation of excess Fe is considered to be a key step towards the same-level recycling of aluminum alloy scrap with extremely economic and environmental benefits. A supergravity-induced technology was employed to purify the contaminating elements from molten aluminum scraps through Al2O3 CFF (Al2O3 ceramic foam filter). During the filtration process, the premature precipitation of Fe-rich phases and Si particles in the molten aluminum scraps were intercepted near the inner wall of Al2O3 CFF. Resultantly, the removal rate of Fe and Si reached 83.98 % and 49.67 %, respectively, at T = 690 ℃ and G= 30 via Al2O3 CFF of P = 80 ppi with H= 40 mm. A continuously supergravity-induced separation on industrial scale was further performed and the removal rate of Fe and Si were 83.5 % and 48.3 %, respectively.

Numerical Modeling of a Sustainable Solid-State Recycling of Aluminum Scraps by Means of Friction Stir Extrusion Process.

One of the most important purposes of the modern industry is a sustainable production, considering the minimization of the energy and of the raw materials used, together with the reduction of polluting emissions. In this context, Friction Stir Extrusion stands out, since it allows to obtain extrusions starting from metal scraps deriving from traditional mechanical machining processes (e.g., chips deriving from cutting operations), heated only by the friction generated between the scraps and the tool, so avoiding the material melting phase. Given the complexity of this new kind of process, the objective of this research is the study of the bonding conditions considering both the heat and the stresses generated during the process under different working parameters, namely tool rotational and descent speeds. As a result, the combined approach involving the Finite Element Analysis and the Piwnik and Plata criterion proves to be a valid tool for forecasting if bonding phenomenon occurs and how it is influenced by the process parameters. The results have also demonstrated that it is possible to achieve completely massive pieces between 500 rpm and 1200 rpm, but at different tool descent speeds. Specifically, up to 1.2 mm/s for 500 rpm and just over 2 mm/s for 1200 rpm.

Carbon-Neutral Steel Production and Its Impact on the Economies of China, Japan, and Korea: A Simulation with E3ME-FTT:Steel

The iron and steel industry is a large emitter of CO2 globally. This is especially true for the iron and steel industries in China, Japan, and Korea due to their production volumes and the prevalence of carbon-based steel production. With few low-carbon and commercially available alternatives, the iron and steel industry is truly a hard-to-abate sector. Each of the countries of interest have committed to a net-zero future involving the mitigation of emissions from steel production. However, few studies have investigated the means by which to achieve decarbonization beyond the inclusion of price signalling policies (e.g., carbon tax or emission trading schemes). Here, we use E3ME-FTT:Steel to simulate technology diffusion in the ISI under several policy environments and we investigate the likely impacts on the wider economy. The results show that penalizing carbon intensive processes can incentivize a transition towards scrap recycling, but it is relatively unsuccessful in aiding the uptake of low carbon primary steelmaking. A combination of support and penalizing policies can achieve deep decarbonisation (>80% emission reduction compared with the baseline). Mitigating the emissions in the iron and steel industry can lead to economic benefits in terms of GDP (China: +0.8%; Japan: +1.3%; Korea: +0.1%), and employment (Japan: +0.7%; Korea: +0.3%) with China, where job losses in the coal sector would negate job gains elsewhere, as the exception.

The Current Situation, Development, and Prospects of the Iron and Steel Industry in the Process towards the “Dual Carbon” Goals

The iron and steel industry is the largest carbon emitter in China’s manufacturing sector and one of the most important fields in the country’s response to climate change. This paper aims to explain the current situation, technological pathways, and future direction of green and low-carbon development of the iron and steel industry. According to the carbon emissions of the iron and steel industry, this paper analyzes the relationship between steelmaking technologies and carbon emissions, as well as the transformation trend of the world’s iron and steel industry, finding that China’s iron and steel industry faces both opportunities and challenges. Steel scrap recycling and electric furnace steelmaking technologies, re-electrification, hydrogen metallurgy, resource recycling and by-products, and carbon capture and utilization (CCU) are the main technologies tailored to the transformation pathways, and the optimization of energy consumption structure is an important direction for future development. Therefore, this paper believes that clean energy, as a guarantee for carbon mitigation, will play an increasingly important role in the process towards achieving carbon peaking and carbon neutrality goals (the “dual carbon” goals), in addition to the transformation of metallurgical technologies.

Recycling high impact polystyrene: Material properties and reprocessing in a circular economy business model

An account is presented of successfully implemented Extended Producer Responsibility (EPR) with recycling to high value products, to help overcome barriers and generate confidence in moving towards Circular Economy (CE) business models. A template for organisations proposing to recycle a thermoplastic is provided by describing appropriate tests and considerations in implementing the recovery and re-use of high impact polystyrene (HIPS) based on a practical, industry case. Simulating the repeated 100% closed loop reprocessing of production scrap, original HIPS has been injection molded to produce tensile and impact test pieces, reground and reprocessed eight times. Assessing the present results together with literature, repeated recycling of production scrap is possible without the need for a remedial compounding step, or changes to processing parameters. Integral to the EPR model is recovery of plastic from returned end-of-life (EoL) products, and in relation to the in-use environment, studies of the effects of UV exposure on virgin material show that significant property degradation can occur. However, with indoor use, as in the present case, this is not seen. Within the CE business model it is desirable to use blends of recovered HIPS originating from different original resin manufacturers. Feeding dry blend regrind directly to the molding machine proved satisfactory, avoiding the need for a compounding/pelletizing step. As an outcome of this study, products are being successfully manufactured from 100% HIPS recovered from EoL products in an environmentally and economically positive CE plan.

Experimental Analysis and Evaluation of the Compressive Strength of Rubberized Concrete During Freeze–Thaw Cycles

Recycling scrap tires provides an alternative source of fine aggregates for the production of rubberized concrete and this will lead to significant increase in concrete frost resistance, environmental protection, and conservation of natural sand and gravel resources. In this paper, a total of 25 groups of rubberized concrete were produced by adding scrap tire rubber particles of different sizes, contents, and pretreatment methods to replace the fine aggregate, and their compressive strength during freeze–thaw cycles was studied from both the macro- and meso-perspectives. The results indicated that the decrease in concrete strength and weight was notably restricted by the presence of rubber particles during freeze–thaw cycles. The rubber fine aggregate with smaller particle sizes enhanced the concrete frost resistance more significantly, and the F100 of concrete with rubber particles of 1.0–2.0 mm increased from 76.6 to 86.5% by increasing the rubber content from 0.0 to 5.6%. The effects of rubber fine aggregate on concrete compressive strength during freeze–thaw cycles were quantified. On this basis, a forecast model for rubberized concrete compressive strength in freeze–thaw cycles was proposed, and the effects of the particle size, content, and pretreatment of the rubber particles were considered. The calculated results agreed well with the test results both in this study and the relevant peer studies, indicating that the model can provide a good reference for the design and engineering application of rubberized concrete in frigid environments.

Recycling of waste aluminum scraps to fabricate sulfidated zero-valent iron-aluminum particles for enhanced chromate removal

Massive waste aluminum scraps produced from the spent aluminum products have high electron capacity and can be recycled as an attractive alternative to materials based on zero-valent iron (Fe0) for the removal of oxidative contaminants from wastewater. This study thus proposed an approach to fabricate micron-sized sulfidated zero-valent iron-aluminum particles (S-Al0@Fe0) with high reactivity, electron selectivity and capacity using recycled waste aluminum scraps. S-Al0@Fe0 with a three-layer structure contained zero-valent aluminum (Al0) core, Fe0 middle layer and iron sulfide (FeS) shell. The rates of chromate (Cr(VI)) removal by S-Al0@Fe0 at pH 5.0‒9.0 were 1.6‒5.9 times greater than that by sulfidated zero-valent iron (S-Fe0). The Cr(VI) removal capacity of S-Al0@Fe0 was 8.2-, 11.3- and 46.9-fold greater than those of S-Fe0, zero-valent iron-aluminum (Al0-Fe0) and Fe0, respectively. The chemical cost of S-Al0@Fe0 for the equivalent Cr(VI) removal was 78.5% lower than that of S-Fe0. Negligible release of soluble aluminum during the Cr(VI) removal was observed. The significant enhancement in the reactivity and capacity of S-Al0@Fe0 was partially ascribed to the higher reactivity and electron density of the Al0 core than Fe0. More importantly, S-Al0@Fe0 served as an electric cell to harness the persistent and selective electron transfer from the Al0-Fe0 core to Cr(VI) at the surface via coupling Fe0-Fe2+-Fe3+ redox cycles, resulting in a higher electron utilization efficiency. Therefore, S-Al0@Fe0 fabricated using recycled waste aluminum scraps can be a cost-effective and environmentally-friendly alternative to S-Fe0 for the enhanced removal of oxidative contaminants in industrial wastewater.

Roll-to-roll solvent-free manufactured electrodes for fast-charging batteries

Roll-to-roll solvent-free manufactured electrodes for fast-charging batteries

Aluminium scrap recycling in a production furnace: Minimizing dross formation for sustainable and efficient recovery

This study investigates the optimal conditions for recycling aluminium troma scraps in a 100 kg production furnace, with a focus on minimizing the formation of toxic dross while maximizing yield recovery. The results indicate that maintaining the melting temperature below 750 °C is crucial for enhanced recovery, as high temperatures cause loss of low melting alloying elements and formation of dross and oxides. The established technique successfully produced aluminium ingots with similar chemical composition and microstructure to A356.0 aluminium alloys, with dross formation reduced to 5% by controlling the formation of Al2O3 which results due to the oxidation of the exposed top layer. These findings demonstrate the potential for sustainable and efficient aluminium scrap recycling in industrial settings.

Innovative Use of the Pointillism Technique for the Production of Scrap Metal Mural Art of Kofi Annan for Environmental Sustainability

Scrap metals have been an environmental nuisance blocking the pathways of water and leading to various forms of environmental pollution at Anloga in the Kumasi Metropolis of Ghana. This scrap metal art project was aimed at creatively reusing and re-purposing scrap metals from various construction, dump sites and households for the creation of a metal artwork as a step in reviving scrap metal art for environmental sustainability. Over the years, murals have been made using various techniques in painting and sculpture. The studio-based research design that employs the qualitative descriptive method was used for this project. The project adopted the concept of pointillism whereby tiny dots in various pure colours are used in creating an artwork that is appreciated when viewed from a distance. We replicated this concept by representing the dots with metal domes from scrap metals in producing an innovative commemorative metal mural of the former UN General Secretary, Kofi Annan. The researchers employed participant observation and used photographs to collect the data by carefully studying the various scrap metals that were available for the project and by utilizing most metal working techniques. It was very necessary to carry on this project to revive scrap metal art in Ghana which is gradually dying out. The study revealed that recycling and melting of metal scraps should be done in kilns and furnaces rather than in open hearth processes for best results. The study recommends the exploration of other methods of doming in the future for much efficiency. Also, the study recommends the exploration of other fine art techniques and media using various scrap metals for artistic production.

Health Risk Assessment of Heavy Metals in Soil around Metal Scrap Recycling Areas during Wet and Dry Seasons in Ogijo, Ogun State, SW Nigeria

Aim: The aim of the study is to investigate the levels and risks associated with heavy metals in the soil samples collected during the dry and wet seasons around metal scrap recycling areas in Ogijo, Ogun State.
 Study Design: The soil samples were collected randomly within the industries and communities in the vicinity of the scrap metal recycling industries (SMRI) and analyzed with XRF.
 Place and Duration of Study: The study was carried out in Ogijo in Sagamu Local Government Area, Ogun State, located within Southwestern Nigeria. The soil samples were collected in dry and wet seasons (5th to 7th March and 24th to 25th September 2020 respectively.
 Methodology: Soil samples within the industries and communities in the vicinity of the SMR were collected randomly, dried, and then sieved through a 2mm mesh stainless sieve. The sieved sample was analyzed for heavy metal concentration by using S2 Ranger, and Bruker UKX-Ray Fluorescence Spectroscopy techniques (XRF).
 Results: The results of the analyzed soil showed that the range of concentrations of heavy metals in the soil samples collected during dry season were: Fe (40100 - 87300 mg/kg); Mn (400 - 3500 mg/kg); Zn (600 -1300 mg/kg); Pb (400 - 1000 mg/kg) and during wet season: Fe (26100 -82700); Mn (500- 4200) mg/kg. Zn (600 – 1300) mg/kg; and Pb were only detected in S3 sample (600mg/kg). The results of the heavy metals were found to exceed the WHO permissible limits of heavy metals. Contamination index, degree of contamination, and pollution load indices indicated slight contamination to excessive pollution, very high risk of the degree of contamination, and extremely polluted soils respectively. The geo-accumulation index was uncontaminated to moderate contamination (0<Igeo≤1) with different metals at different locations that were not detected and with all the detected Zn concentrations (except at S1) to extreme contamination (Igeo≥5).Heavy metal enrichment during both dry and wet seasons ranged from background rank (EF ≤ 1) to moderate enrichment. Eri values ranged from low (Eri) <40) to moderate ecological risk (Eri > 80) with all the risk indices of the locations low (RI <150). The cumulative non-carcinogenic, health index (HI) for ingestion and dermal for soil during the dry season were all above 1 indicating non - carcinogenic health concerns for the residents of the study areas as they recorded higher values. The CRI was far above the acceptable limit indicating that residents in S3 during the wet season and S2 and S9 during the dry season have the probability of contracting cancer through ingestion within the life time of 70 years.
 Conclusion: The results of pollution indices show that the quality of soil in the study entirely deteriorated with respect to the DPR background. This indicates that the soil could not be used for any agricultural or domestic purposes.

Development and implementation of a significantly low-cost 3D bioprinter using recycled scrap material.

The field of 3D bioengineering proposes to effectively contribute to the manufacture of artificial multicellular organ/tissues and the understanding of complex cellular mechanisms. In this regard, 3D cell cultures comprise a promising bioengineering possibility for the alternative treatment of organ function loss, potentially improving patient life expectancies. Patients with end-stage disease, for example, could benefit from treatment until organ transplantation or even undergo organ function restoration. Currently, 3D bioprinters can produce tissues such as trachea cartilage or artificial skin. Most low-cost 3D bioprinters are built from fused deposition modeling 3D printer frames modified for the deposition of biologically compatible material, ranging between $13.000,00 and $300.000,00. Furthermore, the cost of consumables should also be considered as they, can range from $3,85 and $100.000,00 per gram, making biomaterials expensive, hindering bioprinting access. In this context, our report describes the first prototype of a significantly low-cost 3D bioprinter built from recycled scrap metal and off-the-shelf electronics. We demonstrate the functionalized process and methodology proof of concept and aim to test it in different biological tissue scaffolds in the future, using affordable materials and open-source methodologies, thus democratizing the state of the art of this technology.

Recycling of garments scrap

The garments factories left behind different quantities of scraps of waste and unnecessary clothes utilized but can recycle this scraps and tap including in other applications. The aim is to recycle clothes scraps and use it in two applications, the first application is to manufacture clothes for baby clothes using a singer machine and over lock machine and the second application is wood industry compressed using the method a mechanical machine hot pressure. Results obtained from the first application is baby clothes close quality of clothes imported and results are made get it from the second application they are fragile plank samples compact and that proportion of the substance . Large quantities of scarps are extracted from garment factories that cannot be counted, these factories use different raw material and pattern of fabrics in the manufacture of different type of clothing.

Retrospective Evaluation of Liver and Kidney Functions in Patients with Chronic Occupational Lead Intoxication Treated with EDTA Chelation Therapy

Objective: This study aimed to investigate hepatic and renal functions in patients who received calcium disodium edetate (CaNa2EDTA) chelation treatment for chronic occupational lead intoxication. Material and Methods: This single-center retrospective descriptive research was conducted in a secondary-level health facility. The study included patients treated with CaNa2EDTA chelation for chronic occupational lead intoxication between September 15, 2020, and May 31, 2021. Demographic and occupational characteristics, as well as and laboratory parameters obtained before and after the chelation therapy were evaluated. Results: All 75 patients were male, and 73.3% had an occupation in metal scrap recycling. Renal parameters were within normal range before and after the chelation. However, mild elevations were observed in liver parameters. After the adjustment for demographic and occupational variables, the odds of having an elevated liver parameter and an elevated alanine transaminase (ALT) result after the chelation therapy were 9.3 (95%CI 2.6–33.2, p<0.001) and 11.4 (95%CI 2.4–53.2, p<0.001) for patients with pre-chelation elevated any liver parameter and pre-chelation elevated ALT result, respectively. Conclusion: The current study documented mild elevations of the liver parameters in patients with chronic occupational lead poisoning after CaNa2EDTA chelation therapy, particularly those with elevated basal liver parameters, although their renal parameters stayed within reference ranges. The results serve as an example of the safe application of CaNa2EDTA chelation for chronic occupational lead poisoning, by monitoring kidney and liver parameters in a secondary-level health facility. Future prospective studies with structured treatment protocols may investigate the risk and determinants of hepatic and renal adverse effects.

Towards net-zero emissions concrete and steel in India, Brazil and South Africa

ABSTRACT Working with in-country modelling teams and models, targeting net-zero CO2 emissions by later this century, and using decomposition and emissions driver analysis, we develop low emissions cement and steel scenarios linked to usable policy levers for Brazil, India, and South Africa. We find significant mitigation potential from a ‘current policy’ scenario on the demand side (13–26%) and the production side (58–71%), but these countries’ substantial needs for more basic infrastructure – and thus for cement and steel inputs – indicate net-zero will remain very challenging. Demand-side material efficiency reductions, where less steel and cement deliver the same service through better design, will require decades of educational and regulatory efforts, working with buildings sector and infrastructure supply chain actors to reach full potential. In the short to medium run, focusing on reducing emissions from production may deliver more near-term cumulative mitigation by allowing close attention to a small number of domestic companies with high managerial, technical, and financial capacity. To achieve such reductions, governments should encourage the concentration of cement and concrete making at professional facilities to allow the use and regulation of already commercialized lower GHG practices like cementitious material clinker replacement and better concrete mixing while planning for future carbon capture and storage. Governments should also encourage investment in secondary steel making using electric arc furnaces to reuse local recycled scrap, eventually supplemented with increasingly low emission primary iron. International cooperation and support are needed to agree on and implement CO2 intensity accounting systems, improve access to low-emissions production technologies through innovation and commercialization combined with technology transfer or co-development, and offer financial and technical support for clean production investments. Key policy insights On the demand side, international buildings organizations and domestic building code regulators should work with architects, structural engineers, and construction companies to implement regionally appropriate material efficiency options. On the production side, international cement and steel organizations, governments and domestic firms should explore cooperation on technology innovation and transfer, finance, and private and public lead market mechanisms, e.g. premia for low emission production and green procurement. Adaptive long-term sectoral strategies addressing demand and supply will need to be developed with all affected parties.

Material Flows and Waste Management of Titanium Products in China from 2005 to 2020.

The online version contains supplementary material available at 10.1007/s40831-023-00667-4.

Effective pathways for energy conservation and emission reduction in iron and steel industry towards peaking carbon emissions in China: Case study of Henan

As the world's largest steel producer, China's iron and steel industry is facing an urgent task need for energy conservation and emission reduction. Discussion of the green and low-carbon transformation of the iron and steel industry at the provincial level is critical for achieving China's ‘Dual-carbon target’. To explore the road-map towards peaking carbon emissions of the iron and steel industry, a comprehensive assessment framework, based on steel demand and scrap recycling model alongside energy consumption-carbon emission-air pollutant emission model, was developed. Five scenarios were designed to quantify the potential for energy conservation and emission reduction of the iron and steel industry in Henan Province. The material flow analysis model predicted that the total steel demand will peak at 36.06 Mt in 2020, and the steel demand of main sub-sectors such as construction, machinery, vehicle, appliances and others will peak before 2024. Driven by the boom in depreciation scrap, future steel scrap resources and scrap ratio will show a significant growth trend. By 2035, the integrated scenario will show the most significant potential, and the emissions of CO2, SO2, NOx, CO, PM10, PM2.5, and VOCs will decrease by 55.2%, 54%, 33.3%, 16.6%, 43%, 36.4%, and 31.8%, compared to that in the business-as-usual scenario. The results also indicated that advanced technology implementation poses an advantage in mitigation potential before 2025, while electric arc furnace promotion and hydrogen substitution will be the main forces for energy conservation and emission reduction in the iron and steel industry from a long-term perspective. Finally, several policy recommendations regarding the transformation direction for the government and steelmakers were proposed here.

Economic and Environmental Sustainability of an Innovative Cryo-Mechano-Hydrometallurgical Process Validated at Pilot Scale for the Recycling of Li Batteries

An innovative cryo-mechano-hydrometallurgical process (named LIBAT) was demonstrated at pilot scale for the treatment of EOL lithium primary batteries with chemistry Li(0)-MnO2. The process allowed the recycling of steel scraps from external cases after cryomechanical dismantling, and the recovery of Mn and Li products after hydrometallurgical processing. During demonstration activities, about nine tons of batteries were treated in the cryomechanical section, and one ton of black mass was treated in the hydrometallurgical section for the recovery of Mn hydroxides and Li2CO3. The environmental impacts of the process were evaluated in comparison with an innovative pyrometallurgical approach allowing Li recovery, confirming the benefits of the proposed process due to a reduction in energy consumption. Process simulations were performed considering different mixture feeds (only Li primary, or mixture with Li-ion batteries) and process options (only the cryomechanical section of the integral process) to assess the lower limits of potentiality that would ensure economic sustainability.

Direct Recycling of WC-Co Grinding Chip.

Grinding is a finishing process for high precision, high surface quality parts, and hard materials, including tool fabrication and sharpening. The recycling of grinding scraps, which often contain rare and costly materials such as tungsten carbide (WC-Co), has been established for decades. However, there is a growing need for more energy-efficient and environmentally friendly recycling processes. Currently, grinding sludges, which are a mixture of abrasives, lubricants, and hard metal chips, are only treated through chemical recycling. Direct recycling ("reuse" of chips as raw material) is the most effective but not yet viable process due to the presence of contaminants. This paper presents an oil-free dry grinding process that produces high-quality chips (i.e., oil-free and with few contaminants, smaller than 60 mesh particle size) that can be directly recycled, as opposed to the oil-based wet grinding that generates sludges, which require indirect recycling. The proposed alternative recycling method is validated experimentally using WC-Co chips from a leading hard metals' processing specialized company. The contaminant level (oxygen 0.8 wt.%, others < 0.4 wt.%), granulometry (chip D50 = 10.4 µm with grain size < 3 µm) and morphology of the recycled chips' powder is comparable to commercial powders proving the research and industrial potential of direct recycling. The comparison of sintered products using recycled and commercial powder provided equivalent characteristics for hardness (HRA of 90.7, HV30 of 1430), porosity grade (A02-04) and grain size (<3 µm).