Comparative analysis of various machine learning algorithms to predict strength properties of sustainable green concrete containing waste foundry sand.

The use of waste foundry sand (WFS) in concrete production has gained attention as an eco-friendly approach to waste reduction and enhancing cementitious materials. However, testing the impact of WFS in concrete through experiments is costly and time-consuming. Therefore, this study employs machine learning (ML) models, including support vector regression (SVR), decision tree (DT), and AdaBoost regressor (AR) ensemble model to predict concrete properties accurately. Moreover, SVR was employed in conjunction with three robust optimization algorithms: the firefly algorithm (FFA), particle swarm optimization (PSO), and grey wolf optimization (GWO), to construct hybrid models. Using 397 experimental data points for compressive strength (CS), 146 for elastic modulus (E), and 242 for split tensile strength (STS), the models were evaluated with statistical metrics and interpreted using the SHapley Additive exPlanation (SHAP) technique. The SVR-GWO hybrid model demonstrated exceptional accuracy in predicting waste foundry sand concrete (WFSC) strength characteristics. The SVR-GWO hybrid model exhibited correlation coefficient values (R) of 0.999 for CS and E, and 0.998 for STS. Age was found to be a significant factor influencing WFSC properties. The ensemble model (AR) also exhibited comparable prediction accuracy to the SVR-GWO model. In addition, SHAP analysis revealed an optimal content of input variables in the concrete mix. Overall, the hybrid and ensemble models showed exceptional prediction accuracy compared to individual models. The application of these sophisticated soft computing prediction techniques holds the potential to stimulate the widespread adoption of WFS in sustainable concrete production, thereby fostering waste reduction and bolstering the adoption of environmentally conscious construction practices.

Complete physico-chemical characterisation of foundry waste.

The manufacture of foundry metal parts generates various types of mineral wastes. Studies mentioned in the literature are mainly interested in the characterisation of foundry sands and their recycling way. The other wastes (finer than sand) are not dealt and are currently stored in landfills without any recycling solution. This paper aims to fill this gap and reports the complete characterisation of foundry wastes (FW) we carried out to find a way of recycling these materials. FWs were characterised by X-ray fluorescence, X-ray diffraction, scanning electron microscopy and thermogravimetry analyses (TGAs). Leaching tests complying with the NF EN 12457-2 standard were also carried out to evaluate the pollution degree of the different waste products. The results of this work that foundries do not produce just one type of waste, but several. Five types of waste were thus analysed and the results indicated in the first step that each sand was unique and in a second one that the two foundries present a certain similarity with regard to their materials. This complete characterisation study will provide a better understanding of their chemical composition and degree of pollution, so that they can be used more effectively in cement blends, which will be the subject of the rest of this study. The reuse of FW in concrete and mortars is possible and can reduce the environmental impact caused by their storage in landfills.

More resource efficient recycling of copper and copper alloys by using X-ray fluorescence sorting systems: An investigation on the metallic fraction of mixed foundry residues.

According to the state of the art, most of the mixed copper and copper alloy scrap and residues are processed in a copper smelter. Despite the environmental and economic advantages relative to primary production, the recycling of copper and its alloying elements (zinc, tin, lead, nickel, etc.) requires significantly more energy and cost than remelting unmixed or pure scrap fractions such as separate collected material or production scrap. To date, however, less attention has been given to the mechanical purification of mixed scrap. Therefore, sorting by alloy-specific components (SBASC) using an industrial X-ray fluorescence (XRF) sorting system was tested on the coarse metallic fraction (10-32 mm) of mixed foundry residues. The findings show that XRF-SBASC can recover higher-grade copper concentrates (reaching 98.3% Cu), leaded brass and complex alloys, such as aluminium bronze and red brass with high purities, for the use in the production of new materials. XRF-SBASC can therefore contribute to a more resource efficient metal recycling, mainly by reducing the energy consumption and loss levels in copper metallurgy.

Applicability of waste foundry sand stabilization by fly ash geopolymer under ambient curing conditions.

Recently, utilizing industrial waste in the construction industry has gained significant attention to meet sustainability demands and mitigate the adverse environmental impacts caused by the construction industry. This study evaluates the engineering properties of waste foundry sand as a target material after stabilization with an environmentally friendly stabilizing agent (fly ash geopolymer), focusing on achieving adequate strength under ambient curing conditions as a feasible choice for road bases in geotechnical applications. While fly ash geopolymer application is typically linked with temperature curing, this research explores its application under ambient curing to enhance feasibility and reduce production costs. The fly ash geopolymer was synthesized by activating fly ash using a combination of sodium hydroxide and sodium silicate. The experimental program investigated the geopolymer-stabilized waste foundry sand at varying dosages of 7, 15, and 25 %, examining physical properties, non-destructive tests, mechanical properties, XRD phase analysis, and SEM observation. The results demonstrated that increasing fly ash dosage significantly enhanced the physical properties, mechanical properties, and microstructure of the geopolymer-stabilized waste foundry sand samples. Dry density improved from 1.75 to 2.02 g/cm3; longitudinal wave velocity increased from 897.3 to 2028.4 m/s, and unconfined compressive strength rose from 109 to 5261 kPa. Notably, only samples with 25% fly ash achieved the requisite strength to satisfy the road base limit (4100 kPa). These outcomes instill confidence in the potential use of waste foundry sand as a construction material and transition it from mere filling material to a valuable resource, furthermore encouraging the adoption of fly ash geopolymer as an environmentally friendly stabilizing agent in geotechnical applications.

Classification of Sand-Binder Mixtures from the Foundry Industry Using Electrical Impedance Spectroscopy and Support Vector Machines.

Molding sand mixtures used in the foundry industry consist of various sands (quartz sands, chromite sands, etc.) and additives such as bentonite. The optimum control of the processes involved in using the mixtures and in their regeneration after the casting requires an efficient in-line monitoring method that is not available today. We are investigating whether such a method can be based on electrical impedance spectroscopy (EIS). To establish a database, we have characterized various sand mixtures by EIS in the frequency range from 0.5 kHz to 1 MHz under laboratory conditions. Attempts at classifying the different molding sand mixtures by support vector machines (SVM) show encouraging results. Already high assignment accuracies (above 90%) could even be improved with suitable feature selection (sequential feature selection). At the same time, the standard uncertainty of the SVM results is low, i.e., data assigned to a class by the presented SVMs have a high probability of being assigned correctly. The application of EIS with subsequent evaluation by machine learning (machine-learning-enhanced EIS, MLEIS) in the field of bulk material monitoring in the foundry industry appears possible.

Sustainable concrete production using toxic foundry sand and its subsequent effect on water contamination.

Amid growing concerns about diminishing river sand resources and escalating environmental apprehensions related to toxic landfill waste, this study explores the potential of Toxic Foundry Sand (TFS) as a substitute for Standard Fine Aggregate (SFA) in concrete production. The investigation into various TFS replacement ratios in M20 concrete focuses on their impact on workability and compressive strength. Although TFS exhibits properties similar to fine aggregate, making it a promising candidate for partial replacement, differences in bulk density and fineness modulus compared to river sand suggest that TFS should be utilized as a partial replacement only. The study proposes an optimal replacement ratio of 30 % TFS and 70 % SFA to achieve satisfactory compressive strength in M20 concrete. The workability of fresh concrete remains unaffected in both nominal and 70:30 mixes, ensuring ease of mixing on the job site. As an innovative aspect, the study includes testing the water exposed to TFS-infused concrete for portability. Prolonged exposure to water on TFS-infused concrete (70:30 mix) raises concerns, as certain parameters such as chloride and hardness exceed acceptable limits. Therefore, careful control and treatment of Toxic Foundry Sand Contact Water (TFSCW) are deemed crucial on job sites to address potential water quality issues and ensure overall environmental safety.

Sustainable approaches in concrete production: An in-depth review of waste foundry sand utilization and environmental considerations.

This review critically evaluates the potential of Waste Foundry Sand (WFS) as a substitute for fine aggregate in concrete, conducting a comparative analysis of its physical and chemical properties against those of natural sand. The study synthesizes findings from various research experiments to determine concrete's most effective WFS replacement percentage. It compiles and analyzes data on how different WFS ratios affect concrete's mechanical properties, including modulus of elasticity and compressive strength. The review also consolidates research on the impact of WFS on concrete's workability, density, and flowability. A key finding is that WFS, categorized as a non-hazardous waste, possesses a diverse particle size distribution, rendering it suitable for recycling in various industrial applications.The study identifies that a 20%-30% replacement of WFS in concrete significantly improves properties such as voids, specific gravity, and density. However, it is essential to note that exceeding a 30% WFS replacement can result in increased carbonation depth and decreased resistance, primarily due to sulfur trioxide (SO3). Further observations indicate that incorporating higher levels of WFS in self-compacting concrete reduces its flowability and increases water permeability. Moreover, the review highlights the regulatory and classification challenges associated with using WFS, particularly its classification as waste, which hampers its widespread adoption in construction. In conclusion, the study recommends implementing End-of-Waste (EoW) regulations to facilitate sustainable recycling and environmental protection. Additionally, it includes a bibliometric analysis of foundry sand research spanning from 1971 to 2020, providing a comprehensive summary of the field's historical and recent developments.

Congo red dye degradation using Fe-containing mineral as a reactive material derived from waste foundry dust.

This study investigated the applicability of industrial waste. The high affinity of Fe-based products is widely used for industrial effluents because of their capability to oxidize contaminants. Waste foundry dust (WFD) is an Fe oxide that has been investigated as a potential reactive material that causes the generation of reactive oxidants. We aimed to investigate the physicochemical properties of WFD and the feasibility in the Fenton oxidation process. The WFD was used as a catalyst for removing Congo red (CR), to evaluate the generation of •OH and dissolution of Fe during the oxidation process. The linkage of •OH generation by WFD with eluted Fe(II) through the Fe dissolution was found. The Fenton oxidation reaction, CR degradation was affected by H2O2 concentration, initial pH, WFD dosage, initial CR concentration, and coexisting anions. The CR degradation efficiency increased with an increase in H2O2 concentration and WFD dosage. In addition, chloride and sulfate in solution promoted CR degradation, whereas carbonate had a negative effect on the Fenton oxidation process. The elution of Fe promotes CR degradation, over three reuse cycles, the degradation performance of the CR decreased from 100 to 81.1%. For the Fenton oxidation process, •OH generation is linked to Fe redox cycling, the surface passivation and Fe complexes interrupted the release of reactive oxidants, which resulted in the degradation of the CR decreased. This study proposed that WFD can serve as catalysts for the removal of CR.

Recovery of Residual Lead from Automotive Battery Recycling Slag Using Deep Eutectic Solvents.

In this study, we address the ecological challenges posed by automotive battery recycling, a process notorious for its environmental impact due to the buildup of hazardous waste like foundry slag. We propose a relatively cheap and safe solution for lead removal and recovery from samples of this type of slag. The analysis of TCLP extracts revealed non-compliance with international regulations, showing lead concentrations of up to 5.4% primarily in the form of anglesite (PbSO4), as detected by XRF/XRD. We employed deep eutectic solvents (DES) as leaching agents known for their biodegradability and safety in hydrometallurgical processing. Five operational variables were systematically evaluated: sample type, solvent, concentration, temperature, and time. Using a solvent composed of choline chloride and glycerin in a 2:1 molar ratio, we achieved 95% lead dissolution from acidic samples at 90 °C, with agitation at 470 rpm, a pulp concentration of 5%, and a 5 h duration. Furthermore, we successfully recovered 55% of the lead in an optimized solution using an electrowinning cell. This research demonstrates the ability of DES to decontaminate slag, enabling compliance with regulations, the recovery of valuable metals, and new possibilities for the remaining material.

Investigation study data to develop sustainable concrete mix using waste materials as constituents.

Sustainable construction materials are those which contributes towards the carbon- negative process of manufacturing. Cement produced by raw materials from industrial wastes and non-fossil fuel sources is considered as green cement which has high potential in constructions due to high tensile strength and resistance to corrosion. Exploring replacement materials for conventional cement is an active area of research. This data investigation focused on development of novel concrete mix with various proportions of sustainable supplementary materials with cement, fine and coarse aggregate substances. Alccofine, Metakaolin, GGBFS, Foundry sand, Copper slag, Recycled aggregate and Sintered fly ash aggregate are suitable supplementary materials of the concrete mix. Data projected replacement of cement by 15 % Alccofine, 10% Metakaolin and 30% GGBFS substitution and Fine aggregates (50% Copper slag, 30% Foundry sand) and replacement of Coarse aggregate (20% Recycled and 30% Sintered Fly Ash aggregate) will produce sustainable concrete mixture. Compressive and split tensile strength examined at 7th, 14th and 28th day and compared with conventional concrete. This data shows that the concrete mixture CFACA 1234567 was outperformed among the five mixture studied.

Ontologies for increasing the FAIRness of plant research data.

The importance of improving the FAIRness (findability, accessibility, interoperability, reusability) of research data is undeniable, especially in the face of large, complex datasets currently being produced by omics technologies. Facilitating the integration of a dataset with other types of data increases the likelihood of reuse, and the potential of answering novel research questions. Ontologies are a useful tool for semantically tagging datasets as adding relevant metadata increases the understanding of how data was produced and increases its interoperability. Ontologies provide concepts for a particular domain as well as the relationships between concepts. By tagging data with ontology terms, data becomes both human- and machine- interpretable, allowing for increased reuse and interoperability. However, the task of identifying ontologies relevant to a particular research domain or technology is challenging, especially within the diverse realm of fundamental plant research. In this review, we outline the ontologies most relevant to the fundamental plant sciences and how they can be used to annotate data related to plant-specific experiments within metadata frameworks, such as Investigation-Study-Assay (ISA). We also outline repositories and platforms most useful for identifying applicable ontologies or finding ontology terms.

Performance of Eco-Friendly Cement Mortars Incorporating Ceramic Molds Shells and Paraffin Wax.

The lost wax foundry industry has been rapidly expanding in recent years, generating a large amount of waste due to the fact that most of the durable goods include castings and the need for dimensional precision castings for specific purposes, such as the automotive and aeronautics sectors. The waste produced by this industry is currently being deposited in landfills because practical applications are not known and cannot be reused in a new production process, and recycling is also a challenge because of the economics of the process. Thus, the main objective of this study consists in the incorporation of the produced wastes by the lost wax casting foundry industry (ceramic molds shells and paraffin wax) as substitutes for natural aggregate in exterior coatings mortars, evaluating their behavior under normal operating conditions and against freeze-thaw actions. The obtained results revealed porosity, flexural strength, and compressive strength adequate under normal operating conditions. The freeze-thaw performance of the mortars with waste incorporation was similar to the mortars developed with natural aggregates. Thus, the potential of the ceramic mold shells and paraffinic waxes utilization in cementitious mortars for the construction sector was demonstrated.

DNA damage in foundry workers using non-invasive micronucleus cytome assay.

Workers in the foundry industry are exposed to hazardous chemical agents such as metal fumes, gases, vapor of molten metal, and respirable dust and hazardous physical agents such as heat, noise, and electromagnetic fields. Co-exposures to hazardous physical and chemical agents in foundry workplaces may cause DNA damage in workers. This study aimed to evaluate DNA damage in foundry workers. Thirty-three exposed foundry workers as a exposure groups and 33 non-exposed individuals as a control groups participated in this study. Buccal micronucleus cytome (BMCyt assay) assay was used to assess DNA damage. Results showed that foundry workers were under exposure to hazardous chemical and physical agents such as metal fumes and noise. The percentage of micronucleus (MN) cells in exposure group (0.59 ± 0.93 %) were statistically higher than control group (0.23 ± 0.23 %) (P < 0.05) %). Also, the percentage of nuclear bud cells and binucleated cells in exposure group were statistically higher than control group (P < 0.05). The percentage of differentiated normal cells were significantly higher in the control group compared to the exposed group (P < 0.05). Foundry workers are at risk of DNA damage; therefore, prevention measures need to be implemented to reduce exposure to air pollutants in foundry workplaces.

Thermostability of Organobentonite Modified with Poly(acrylic acid).

A new type of organobentonite foundry binder composed of a composite of bentonite (SN) and poly(acrylic acid) (PAA) was analyzed using thermal analysis (TG-DTG-DSC) and pyrolysis gas chromatography mass spectrometry (Py-GC/MS). The temperature range in which the composite retains its binding properties was identified using thermal analysis of the composite and its components. Results showed that the thermal decomposition process is complex and involves physicochemical transformations that are mainly reversible at temperatures in the ranges of 20-100 °C (related to evaporation of solvent water) and 100-230 °C (related to intermolecular dehydration). The decomposition of PAA chains occurs between 230 and 300 °C, while complete decomposition of PAA and formation of organic decomposition products takes place at 300-500 °C. Dehydroxylation of montmorillonite (MMT) in bentonite begins at about 500 °C, which leads to a drastic structural transformation. An endothermic effect associated with the remodeling of the mineral structure was observed on the DSC curve in the range of 500-750 °C. The produced SN/PAA composite was found to be thermostable during degradation in both oxidative and inert atmosphere, similar to the starting bentonite, and even maintained over a relatively higher and wider temperature range compared to organic binding materials used. At the given temperatures of 300 °C and 800 °C, only CO2 emissions occur from all the examined SN/PAA samples. There is no emission of compounds from the BTEX group. This means that the proposed binding material in the form of the MMT-PAA composite will not pose a threat to the environment and the workplace.

Mechanical Reclamation of Spent Moulding Sand on Chromite Sand Matrix; Removal of Alkali-Phenolic Binder.

The foundry industry generates large amounts of waste when casting metal into sand moulds. An important issue is the activities that are related to the re-recovery of the grain matrix (the main component of the moulding sand) for realising subsequent technological cycles. This process is particularly important in the case of the expensive chromite matrix that is necessary for use in manganese steel casting. The effects of the reclamation treatments of spent alkali-phenolic binder sand were evaluated by scanning electron microscopy with EDS, analysing the chemical composition in micro areas and proving the loss of binder on the surfaces of the matrix grains. Tests were also performed using the main criteria for evaluating a reclaimed organic binder: sieve analysis and ignition loss. A thermogravimetric analysis study was performed to assess the change in the chromite character of the grain matrix under the influence of temperature. The effects of the reclamation measures were verified by making moulding compounds on a matrix of reclaimed sand and a mixture of reclaimed and fresh sand. The tests and analyses that were carried out indicated the direction of an effective method for reclaiming used alkali-phenolic binder masses and the extent of the proportion of the regenerate in moulding sand in order to maintain the relevant technological parameters of the moulding sand.

Flotation separation of coal dust from foundry dust enhanced by pre-soaking assisted mechanical stirring.

Foundry dust is the main refractory solid waste in the foundry industry, and its resource utilization is a top priority for realizing green and cleaner production. The massive amount of coal dust in foundry dust is a potential impediment to the recycling of foundry dust, and the efficient separation of coal dust is crucial to solving the above problems. In this paper, the flotation separation of coal dust from foundry dust enhanced by pre-soaking assisted mechanical stirring was reported. The influence of pre-soaking, stirring speed, and stirring time on the flotation results of foundry dust was systematically studied, and the enhancement mechanism was analyzed based on the microstructure and hydrophobicity of foundry dust. Flotation kinetics experiments with different stirring time were conducted to clarify the flotation process of foundry dust. The results indicate that the pre-soaking of foundry dust is beneficial for the water-absorbing swelling of clay minerals coated on the surface of coal dust, and the subsequent mechanical stirring pretreatment promotes the monomer dissociation of foundry dust, which increases the contact angle of foundry dust and considerably improves the flotation results. The optimal stirring speed and stirring time were 2400 rpm and 30 min, respectively. The classical first-order model presented the highest degree of fitting with the flotation data among the five flotation kinetics models. Therefore, the pre-soaking assisted mechanical stirring is a promising method for promoting flotation separation and the complete recycling of foundry dust.

Dilatation of New Progressive Hybrid Sand and Its Effect on Surface Structure, Roughness, and Veining Creation within Grey Cast Iron.

The constant effort of all metal alloy manufacturing technologies and processes is to improve the resulting quality of the processed part. Not only the metallographic structure of the material is monitored, but also the final quality of the cast surface. In foundry technologies, in addition to the quality of the liquid metal, external influences, such as the behaviour of the mould or core material, significantly affect the cast surface quality. As the core is heated during casting, the resulting dilatations often lead to significant volume changes causing stress foundry defects such as veining, penetration and surface roughness. In the experiment, various amounts of silica sand were replaced with artificial sand and a significant reduction in dilation and pitting of up to 52.9% was observed. An important finding was the effect of the granulometric composition and grain size of the sand on the formation of surface defects from brake thermal stresses. The specific mixture composition can be considered as an effective prevention against the formation of defects instead of using a protective coating.

Organobentonite Binder for Binding Sand Grains in Foundry Moulding Sands.

A series of studies related to the production of organobentonite, i.e., bentonite-poly(acrylic acid), and its use as a matrix grain-binding material in casting moulding sand is presented. In addition, a new carbon additive in the form of shungite was introduced into the composition of the moulding sand. Selected technological and strength properties of green sand bond with the obtained organobentonite with the addition of shungite as a new lustrous carbon carrier (Rcw, Rmw, Pw, Pw, PD) were determined. The introduction of shungite as a replacement for coal dust in the hydrocarbon resin system demonstrated the achievement of an optimum moulding sand composition for practical use in casting technology. Using chromatographic techniques (Py-GC/MS, GC), the positive effect of shungite on the quantity and quality of the gaseous products generated from the moulding sand during the thermal destruction of its components was noted, thus confirming the reduced environmental footprint of the new carbon additive compared to the commonly used lustrous carbon carriers. The test casting obtained in the mould of the organobentonite moulding sand and the shungite/hydrocarbon resin mixture showed a significantly better accuracy of the stepped model shape reproduction and surface smoothness compared to the casting obtained with the model moulding sand.

A multicomponent quasi-experimental ergonomic interventional study: long-term parallel four-groups interventions.

BACKGROUND: Musculoskeletal disorders (MSDs) are known as one of the main problems affecting the health of industrial workers and can lead to lost working days, functional disability of workers and wasting the financial resources of an organization. Therefore, the present study aimed to evaluating the effect of ergonomic interventions on reducing MSDs and improving working posture in the in a foundry industry workers. METHODS: A field multicomponent cross-interventional study was conducted on workers working in a foundry industry. In this study, 117 male workers were divided into 4 groups, including a control group, a group with specialized ergonomics training, a group with workstation intervention, and a group simultaneously undergoing training and workstation intervention. All 4 groups were evaluated during a period of baseline, 6 and 12-months follow- up. The Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) and direct observations of working postures by using the Quick Exposure Check (QEC) method were used. RESULTS: The results showed that the implemented interventions in the shoulder/arm, back and stress level were effective and the difference in the final score was significant among different groups (P-value > 0.05). In addition, the interventions led to a significant decrease in the QEC scores and musculoskeletal symptom scores in the neck, shoulder, lower back, knee, and lower leg regions among different groups (P-value > 0.05). CONCLUSION: The results showed that workstation modification and training and workstation intervention simultaneously had a greater effect on MSDs and improving working posture compared to training alone.

A new approach for quantifying ecological sustainability in waste management by using the method of modelling.

Human activity has an ever-increasing impact on the environment. In order to understand all processes and interactions behind this change, one has to analyze the environmental impact. Life Cycle Assessments (LCAs) are one way to achieve this, which, however, are time-consuming and often associated with high costs, as well as the requirement of specialized knowledge and software. This paper introduces a model, which allows an initial assessment. The model enables a more pragmatic way and may be considered as a first step in order to implement ecological sustainability considerations into companies. Based on a real-world problem, namely the disposal of foundry dust, the model is explained in a vivid manner.