Metal Products Research Articles

Role of buttering layer composition on microstructural heterogeneity and mechanical properties of Alloy 617 and P92 steel dissimilar welded joints for future Indian AUSC program

AbstractRestrictive operating conditions (even exceeding 700 °C) of materials in advanced ultra super critical (AUSC) power plants and the need to minimize manufacturing and maintenance costs require the production of dissimilar metal welded joints (DMW). Significant differences in the physical and chemical properties of welded materials lead to phenomena that reduce the weldability of the metals used and force the search for solutions that limit unfavorable phenomena, e.g., the use of buttering layers. The study presents a comparison of two types of joints with Alloy 617 (UNS N06617) and ferritic P92 (UNS K92460) steel made using Inconel 82 (ENiCrFe-3) and Inconel 617 (ERNiCrCoMo-1) alloys buttering layer and the corresponding chemical composition of filler metals. All areas of the joints made with the gas tungsten arc welding process were subjected to structural investigations (optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) and mechanical tests (microhardness, room and high temperature tensile, and toughness testing). Despite the more complicated welding procedure, sound welded joints were obtained with favorable properties resulting, inter alia, from the reduced thickness of the martensite layer in HAZ of P92 steel and the limited diffusion of alloy components compared to welded joints without the buttering layer. This also resulted in a reduction of the maximum hardness (especially in the case of Inconel 82 buttering—by 15–30 HV0.5 in comparison with Inconel 617 buttering) and an increase in strength while limiting the decrease in plasticity (even 663 MPa tensile strength and 21% of elongation for Inconel 617 buttered joint). Moreover, improved high-temperature performance (approximately 70–100 MPa) of the welded joint following the application of the buttering layer was confirmed. The presented results allow for drawing general conclusions that both proposed welding procedures can be recommended for use in the working conditions occurring at AUSC.

О литейной форме из поселения эпохи бронзы Тарангул в Актюбинском Приуралье

Introduction. In 2021, the Mugodzhar (Mugalzhar) Crew of the Margulan Institute of Archaeology investigated the site of Tarangul and discovered a casting mold ― a rare artifact of utmost interest related to metal production and processing. Goals. The article seeks to describe and analyze the Bronze Age mold from Tarangul located in the Aktobe Cis-Urals, introduce into scholarly circulation some newly obtained scientific data. Results. The implemented analyses include those of natural science (micro-wear and spectral ones) and comparative typology, the latter to yield a classification of castings and their cultural affiliation. The tool mold has two surfaces with negative impressions. The first one was used to cast three sickles, while the second one (once consisted of two pieces) would cast a flat adze. The shapes attest to the mold was used to cast Kundravinskaya-type sickles widespread across the Late Bronze Age Southern Urals, Middle Volga, and Western Siberia. Kundravinskaya-type sickles are associated with the Alakul culture, the Kozhumberdy cultural group being a local variant of the latter in the region under study. The shape of the impression on the reverse side is characteristic of adzes from the Alakul era discovered in western parts of Eurasia’s steppe zone. The study concludes the mold had first consisted of two pieces and been used to cast adzes, and after the other piece was lost or damaged it started being used to cast sickles. The spectral analysis shows the castings were basically made from copper, and detects some traces of alloying. Another finding is that the three mold negatives were used not simultaneously but rather when and as it was necessary. In general, the conducted tests have well reconstructed the manufacturing techniques and stages of use for the mold from the Late Bronze Age settlement of Tarangul in the Aktobe Cis-Urals, and highlighted certain aspects in the study of molds as a specific source on metal production techniques and technologies in prehistory.

Experimental and dynamic molecular study of zinc extraction from sphalerite concentrate in ternary deep eutectic solvent

The utilization of deep eutectic solvents (DESs) as a novel class of solvents in metal production offers a promising alternative to aqueous solutions due to their biocompatibility and non-aqueous nature. This study investigated the leaching of sphalerite concentrate using a ternary stable DES composed of choline chloride (ChCl), p-toluene sulfonic acid (PTSA), and ethylene glycol (EG) (at a molar ratio of 1:1:1). The effects of time, temperature, and milling time on zinc recovery were examined within specific ranges (20–1440 min, 40–100 °C, and 0–24 h, respectively). The study revealed the significant influence of time and temperature on zinc dissolution efficiency within ChCl:PTSA:EG. Higher temperatures and longer leaching times were found to improve efficiency substantially. The research emphasized the crucial role of milling time, demonstrating that longer durations enhanced zinc efficiency by introducing more defects on the sphalerite surface and reducing particle size. Under optimized conditions, including a temperature of 100 °C, 24 h of ball milling, and 1440 min of leaching, a zinc recovery of 99.7% was achieved. Infrared analysis confirmed the chemical stability of the solvents during the leaching process. The sphalerite leaching process involved the formation of zinc chloride ion complexes and evolution H2S gas. An unexpected finding is the presence of lead sulfate in the leach residue, which may be attributed to sulfide oxidation to sulfate species. The Avrami kinetic model provided an excellent fit with the sphalerite dissolution data in ChCl:PTSA:EG DES, indicating that the rate-controlling step was primarily influenced by the diffusion process. R2 values for kinetics fitting data were in the range of 0.87–0.97 for temperature of 40–100 °C. The molecular dynamic (MD) simulation findings indicated robust electrostatic interactions between the metal ions Zn2+ and Fe2+ and the Cl− ions of the ChCl molecules. Additionally, the MD calculations showed that the metal ions formed complexes with some O-S-O atoms within the PTSA molecule.

Combined DFT and ionic model computational study of the effect of alkali metal cations on the structure, bonding and properties of molten cryolites, M3AlF6 (M = li, Na, K, Rb, and Cs)

ABSTRACT Ionic melts, in the form of ionic liquids and molten salts, are important in many technological aspects such as metal production and energy applications. Cryolite melts constitute an important family especially for the industrial production of Al. The present computational study aims to analyse the effect of different cations on the structure and properties of Al (III) fluorocomplexes in cryolite melts. Cation effects are discussed as the ion pair interactions due to alkali metal cations of cryolite compounds M3AlF6 with M= Li, Na, K, Rb, or Cs for various microclusters using ionic interaction model (IM) and DFT calculations. DFT results for different ion complexes are compared with the energy calculations using a pseudoclassical model for isolated clusters. QTAIM and ELF analyses were performed to understand the nature of interactions in detail. A link between open-shell interactions and decreased ionic conductivity is proposed within the series of K, Rb, and Cs. Environmental effects, such as temperature and presence of other ions, are investigated in detail by DFT analysis.

A review of cooling in the industry

In modern society, metal products are needed in various industries. The annealing process is commonly employed in manufacturing. Based on the specifications of the product, the purpose of annealing is different, the annealing process specification has a variety of commonly used complete annealing, spheroidal annealing, and stress relief annealing. This paper investigates and compares the characteristics of different annealing processes in the production process through the literature research method. This paper describes seven annealing methods, mainly detailing two annealing processes, spheroidizing annealing, and recrystallization annealing, and gives examples of the advantages and disadvantages of these two processes. Annealing is primarily used to improve machinability and reduce hardness. It also stabilizes size, lowers residual stress, and lessens the tendency for deformation and cracking. Cut down on grain, reorganize, and get rid of organizational flaws, even material composition and organization can enhance a material's qualities or prepare it for upcoming heat treatments.

Energy-efficient scientific-technological approaches to the processing of plastic waste PET, PE, PP, PS to produce hydrogen-containing gas and titanium carbide powder

The paper considers gaseous products, structure and phase composition of hard products resulting from high-temperature exothermic reactions between Ti–PET–(PE, PP, PS) system components, depending on the content of oxygen-free polymers polyethylene (PE), polypropylene (PP), and polystyrene (PS) in the initial blend. It is found that the addition of PE, PP, PS polymers to the Ti–PET system increases the hydrogen content from 45 to 62 vol% and reduces the carbon monoxide content from 38 to 20 vol% in gaseous products. According to calculations, the adiabatic flame temperature of the synthesized gas in air is very close to that of pure hydrogen. The synthesized gas can therefore be used as ecological fuel for energy sources. On the other hand, oxygen-free polymers presenting in the system provide the formation of substoichiometric carbide TiC0.75. Its hardness is not lower than that of stoichiometric TiC and even exceeds widely used carbides and borides of transition metals. In addition, the agglomerate structure of synthesized TiC0.75 allows to apply it as a promising ecological basis for highly-efficient abrasive pastes, in particular for polishing and finishing fabricated metal products.

SYNTHESIS OF COPOLYMERS FOR PROTECTIVE COATINGS

Copolymers were obtained in this work and the methodology for their synthesis was worked out. Various fillers were selected for the polymer coating. Resulting copolymers have good adhesion required for composite protective coatings. An experiment was conducted to determine the corrosion resistance of metals coated with copolymers when exposed to aggressive environments, as well as to determine the hardness and thickness of the polymer coatings obtained. It was found that the polymer coating filled with bronze powder, despite the small thickness of 43.4 μm, hasthe best adhesion and corrosion properties, as well as having the highest hardness values of 80.5 HB. Such physical and mechanical properties of polymer coatings allow them to be used as protective coatings for metal products working under the influence of aggressive media.

Comparative life cycle assessment of copper and gold recovery from waste printed circuit boards: Pyrometallurgy, chemical leaching and bioleaching

Printed circuit boards (PCBs) make up a substantial amount of electronic waste (e-waste) generated annually. Waste PCBs contain high quantities of copper and gold in comparison to natural ores. As such, “urban mining” of waste PCBs to recover these metals is of commercial interest. In this work, we used life cycle assessment to compare the environmental impact of four copper and gold recovery processes. We evaluated pyrometallurgy, chemical leaching, and bioleaching, as well as a hybrid leaching process that uses bioleaching to recover copper and chemical leaching to recover gold. Furthermore, we considered differences in environmental impact based on differences in electricity sources. If electricity comes from fossil fuels, the pyrometallurgical process results in the lowest environmental impact in all impact categories studied. If electricity comes from carbon-free sources, the pyrometallurgical process results in the lowest environmental impact in all categories studied except global warming, where the hybrid leaching process results in the lowest impact. In all cases, metal recovery from waste PCBs leads to lower environmental impact than primary metal production. Our goal is to guide e-waste recyclers towards more environmentally sustainable metal recovery processes and to provide knowledge gaps in the field to guide future research.

An Examination of Bronze Vessel Technology in the Unified Silla Period: Case Study on the Bronzes Excavated from Gwanbuk-ri Site in Buyeo

Archaeological excavations in Buyeo had revealed Bronze vessels interred within a hole in the building at the Gwanbuk-ri site. These bronze vessels are dated to the Unified silla period (9-10th centuries). To identify the bronze vessels’ manufacturing technology, metallurgical analyses were carried out using Optical Microscopy, SEM-EDS and EPMA. The results allowed a reconstruction of the manufacturing process of bronze vessels in the Unified silla. It proved that bronze vessels were manufactured with Cu-Sn alloy with varying tin contents, which may be related to the application of uncontrolled procedures in making the bronze alloys. Also a casting process was used to shape the bronze vessels and the strength and hardness of the container were improved through a quenching process. Twins were observed in one of the samples, so it was assumed that hot working had been attempted. Non-metallic inclusions in bronze vessels have circular or polygonal shapes, and Cu and S were detected. The presence of Cu-S inclusions showed the probable use of copper sulphide ores for metal production and smelting. Se and Te in the inclusions of the bronze vessels show that the copper ore is different. From the results of metallurgical analyses of bronze vessels excavated from other regions of the same era, casting and quenching treatments were confirmed, and the sequential relationship of the technological system was revealed.

Indonesia's contribution to global carbon flows: Which sectors are most responsible for the emissions embodied in trade?

Motivated by recent developments in global carbon policies, such as the carbon border adjustment mechanism (CBAM) in Europe and carbon pricing in Indonesia, this paper elaborates on CO2 emissions embodied in products entering and leaving Indonesia and identifies carbon-intensive sectors responsible for carbon leakage. This was performed by using global multi-regional input-output analysis and consumption-based accounting (CBA) - production-based accounting (PBA) ratio. In 2016, the annual CO2 emissions embodied in Indonesia's exports and imports were 114 and 95 Mt. CO2, respectively. Considering final demand only, these values reduce to 32 and 22 Mt. CO2 or 0.9 and 0.6 % of total CO2 emissions in global trade, respectively. The electrical and machinery sector makes up the most CO2 emissions in Indonesian exports. In terms of per USD, metal products and petroleum, chemical and non-metallic mineral products are among the most carbon-intensive sectors, thus likely to be affected by the CBAM policy. Furthermore, Indonesia's emissions under CBA were slightly lower than PBA, indicating that minor carbon leakage occurred in 2016, but this is subject to uncertainty. Assessing the relative CO2 emissions of various economic sectors is suitable for manufacturing goods whose processes are typically dominated by fossil combustion. However, this is not the case for the agriculture sector as its carbon footprint values are underestimated due to the exclusion of land use, land use change, and forestry emissions. Overall, our findings can serve as a baseline to further explore how a transition towards a low-carbon economy in Indonesia could improve global-trade carbon balances.

A tandem approach for precipitant-free highly selective recovery of valuable metals from end-of-life lithium-ion batteries using a green deep eutectic solvent

Recently, recycling lithium-ion batteries (LIBs) waste and the efficient recovery of valuable metals has become crucial for the circular economy. Deep eutectic solvents (DESs) have shown immense potential for metal extraction from end-of-life (EoL) LIBs. However, a complicated subsequent separation process is required due to the non-selectivity of the DES components for metal. Herein, we propose a tandem precipitant-free hydrometallurgical process for the selective recovery of Li and other valuable metals (Ni, Co, Mn) from EoL LIBs using a green DES. The process parameters, viz., reaction temperature (T), time (t), pulp density (S/L), and molar ratio (MR) of ethylene glycol to tartaric acid, were optimized via the statistical optimization technique of response surface methodology. The results revealed maximum extraction efficiencies of 99.2±0.5%, 96.1±1.4%, 95.2±1.2%, and 97.8±1.5% for Li, Ni, Co, and Mn, respectively, under the optimized process conditions of T = 118 °C, t = 17 min, S/L = 42 g/L, and MR = 3:1. The kinetic study showed that interfacial reaction governed the extraction process. A plausible mechanism depicting the role of DES constituents in synergistically facilitating the extraction reaction was elucidated. Moreover, Li and other metals (Ni, Co, and Mn) were selectively separated and recovered with an overall efficiency of ∼99%. The reusability of the recovered metal products and the DES were also assessed for a closed-loop recycling process. At the outset, the proposed process paves the way for a greener alternative for recycling valuable metals from EoL LIBs rather than conventional acid-based leaching processes.

Determining rational parameters for the treatment of concentrated wastewater from etching site by using combined systems producing sediments of predefined composition

The object of this study is model solutions, spent sulfuric acid and chloride acid etching solutions, degreasing of metal products at enterprises. The paper reports results of research on the possibility of obtaining sediments of predefined composition and reducing the consumption of chemical reagents in comparison with conventional cleaning schemes. The systematization of the elements of the technological scheme has been shown, which provides for the treatment of concentrated wastewater of the etching area in combined systems with obtaining sediments of predefined composition and is the basis for the implementation of resource-saving technology. Rational parameters were established for the state (рН=3‒4, Eh=+0.3‒+0.33 V, and rH2=16.3–19.38 V) and technological parameters (degree of iron extraction ψ=0.8, reagent consumption from the stoichiometric norm of B=0.8). Such parameters provide the proper conditions for the oxidation of organic compounds and their co-precipitation with insoluble iron hydroxy compounds (the maximum degree of extraction of organic impurities is 86 %). The formed precipitate corresponds to the FeOOH.nH2O composition, contains 2‒3 % of organic impurities, and is subject to burial. As a result of studies on the treatment of concentrated iron-containing wastewater, the obtained sediment is ready for further utilization by processing. The composition of this sediment corresponds to the natural mineral limonite FeOOH (Fe2O3.nH2O) and is formed at pH values from 3.5 to 7.5 with rH2 values from 26 V to 21 V and at technological regeneration parameters of pH=4.0–4.6; rH2 =23.34–32.25 V. As a result of research into the deep purification of wastewater using a magnetic device, a suspension of sediment of ferromagnetic impurities (hydroxo compounds of iron) is obtained, which could be the basis for extraction or production of magnetically favorable dispersed material.

Metallic minerals production and environmental sustainability in China: Insights using ARDL bounds testing and wavelet coherence approaches

China plays a prominent role in the production and consumption of metallic minerals. However, the mining and smelting processes associated with these minerals contribute significantly to the release of CO2 emissions. This study examines the long-run and causal effects of metallic minerals production, renewable energy consumption, GDP growth, financial development, and urbanization on CO2 emissions in China for the period 1977–2021, using the IPAT framework. This study utilizes various econometric methods, including the Bounds test of co-integration, autoregressive distribution lag (ARDL), wavelet coherence test (WTC), and gradual shift causality tests, to analyze the relationship between the variables. The bounds test demonstrates the cointegration among the variables. The long-run results indicate that metallic minerals production, GDP growth, and urbanization have a positive effect on CO2 emissions, while renewable energy consumption and financial development have a negative effect on CO2 emissions. Further, WTC indicates a significant relationship between CO2 emissions and independent variables. Moreover, causality tests indicate a one-way causal relationship between metallic minerals production, GDP growth, financial development, and urbanization with CO2 emissions. In addition, there is a two-way causal relationship between CO2 emissions and renewable energy consumption. To address the environmental consequences of CO2 emissions, China should implement measures such as metal recycling and the adoption of low-carbon and energy-efficient technologies in the mining and production of metals.

Blast Furnace Slag Formation Prediction Model Using Classical Thermodynamics

Blast furnace (BF) ironmaking is the most widely used technology for hot metal production. In steelmaking industry, 80% of the steel in the world is produced in the BF‐basic oxygen furnace route. It is well known that poor quality of the raw material i.e., high gangue content in the iron ore affects the BF process performance and the cohesive zone formation, which is the most critical zone in the BF operations. Increased gangue content in the iron ore causes variation in the slag formation and slag volume thus affecting the fuel rate and BF performance. Therefore, in this study, the slag formation is studied to understand the slag properties at different locations inside the BF. The model is based on classical thermodynamics and is implemented using ChemApp linked with FactSage databases. The model aids in understanding the slag formation in the BF for various burden chemistry, fuel, and flux inputs. The final hot metal and slag composition along with the exit gas volume and composition predicted from this model are compared with industrial BF plant data operating across different conditions.

Pengaruh Biaya Produksi dan Biaya Operasional Terhadap Laba Bersih

In the business world, effective and efficient cost management is the key to optimizing company profits. The aim of this research is to examine the effect of production and operational expenditure on profit levels at PT Bakrie Metal Industries. The sample in this research refers to the production planning budget report. The method used is a descriptive quantitative research approach, with data obtained through the process of collecting information from production budget planning reports from 2020 to 2022 at PT. Bakrie Metal Industries, a company specializing in the production of corrugated metal products and fabrication projects. The research subject involves production costs, operational costs and net profit from the period 2020 to 2022. Data analysis was carried out through a number of techniques, including normality tests, heteroscedasticity tests, multicollinearity, autocorrelation test, correlation test, multiple linear regression test, coefficient of determination test, as well as t test and F test. The analysis process uses SPSS version 22 software. The results of this research indicate that production costs have an insignificant influence on net profit, while operational costs show a significant influence on net profit. Furthermore, it was found that both production costs and operational costs had a significant impact on the level of profitability at PT Bakrie Metal Industries.

MOX-TiO2 (M=Pt, Pd, Ru) for alcoholysis reaction from furfuryl alcohol to ethyl levulinate

Simple noble metal oxides (PtOx, PdOx, RuOx) based titanium dioxide (Pt–TiO2, Pd–TiO2, Ru–TiO2) were prepared using a facile sol-gel method. The conversion of furfuryl alcohol (FAL) to ethyl levulinate (EL) was studied. Full characterizations were performed using XRD, XPS, Raman and in situ FT-IR. An in-depth study of acidic strength and sites distribution (Brønsted or Lewis) was conducted by NH3-TPD, pyridine-IR. The profiles of H2-TPR and O2-TPD suggested enhanced reducibility and optimum oxygen storage capacity in Pt–TiO2. Remarkable FAL conversion (94.4%), EL yield (89.6%) with productivity (21.3 × 103 molEL/mmolPt h) and TOF (22.5 × 103 molFAL/mmolPt h) were obtained. Metal productivity follows the order: Pt (21.3 × 103 molEL/mmolPt h) > Ru (11.5 × 103 molEL/mmolRu h) > Pd (3.6 × 103 molEL/mmolPd h). Two different reaction pathways were proposed. From computational calculations of charge density differences and Ead value, a robust electron transfer capacity was found in Pt–TiO2, as well as an advantageous FAL adsorption as compared to other catalytic systems.

Dissipation-based life cycle impact assessment of mineral resource use—a review, case study, and implications for the product environmental footprint

Abstract Purpose Impacts of mineral resource use on the availability of resources can be assessed using a broad range of methods. Until recently, life cycle inventory (LCI) and life cycle impact assessment (LCIA) models have been based on resource extraction. As extracted resources are not necessarily “lost” for future use, recent methodological developments have shifted the focus from resource extraction to resource dissipation. This paper aims at reviewing dissipation-based LCIA methods, testing them in a case study, analyzing potential implications for the product environmental footprint (PEF), and providing recommendations for future method development. Method Five recently developed LCIA methods have been reviewed and compared based on 22 criteria, such as the forms and time horizons of dissipation considered, scientific publication, and number of characterization factors (CFs). Additionally, the abiotic depletion potential (ADP) method has been included to serve as a non-dissipation-based reference. All methods are tested in a case study on a theoretical product, designed solely for demonstration purposes, and consisting of 1 kg of the metals aluminum, cobalt, copper, molybdenum, nickel, and zinc. In addition to the absolute LCIA results, the contributions of metal production stages and individual resource extractions/emissions have been investigated. Finally, normalization and weighting have been carried out to analyze consequences of replacing ADP with the new dissipation-based methods in the context of PEF. Results and discussion Most recently developed LCIA methods take a long-term perspective, cover emissions of resources to the environment (and partly technosphere), and vary in the number of CFs and resources covered. The case study results obtained by ADP are dominated by the molybdenum dataset; the results of the dissipation-based LCIA methods are strongly influenced by the cobalt dataset. All results are strongly sensitive to the LCI database used (ecoinvent or GaBi). Normalization and weighting revealed that the mineral resource use impact result dominates the aggregated PEF score (57%), when using the currently recommended ADP model. Shifting from the resource extraction-based ADP to dissipation-based models can reduce the contribution to 23% or < 1% depending on the method. Conclusion The development of methods addressing mineral resource use in LCIA has shifted from resource extraction to dissipation. The analyzed methods are applicable and lead to different findings than the extraction-based ADP. Using the newly developed methods in the context of PEF would significantly change the relevance of the mineral resource use impact category in comparison to other environmental impacts.

A Study on the Removal of Impurity Elements Silicon and Zinc from Rubidium Chloride by Vacuum Distillation.

With the rapid development of high and new technology, rubidium and its compounds show broad application prospect and market demand with their unique characteristics. At present, the production of rubidium metal is mainly prepared by calcium thermal reduction of rubidium chloride. Rubidium metal obtained by reduction requires multi-step vacuum distillation to obtain high-purity rubidium metal. The purity of rubidium metal depends on the purity of the raw material rubidium chloride. Rubidium metal is relatively active and is easy to oxidize and explode in air. Therefore, a method combining vacuum decomposition and vacuum distillation to reduce impurity elements in rubidium chloride from raw materials is proposed in this paper. The experimental results show that under the conditions of pressure of 5-10 Pa, distillation temperature of 823 K and vacuum distillation time of 60 min, the contents of Si and Zn impurities are reduced from 1206 mg/kg and 310 mg/kg to less than 0.1 mg/kg, and the removal rates are 99.99% and 99.97%, respectively. Rubidium chloride has almost no loss, and through one-step vacuum distillation, the impurity elements silicon and zinc can be deeply removed, reducing the flammability and explosiveness, high cost, long process and other problems caused by the subsequent preparation of high-purity rubidium metal.

Rapid iron extraction from nickel leaching residue by a hydrogen plasma smelting reduction

The processing of limonite-type lateritic nickel ore through sulfuric acid leaching generates leaching residue that requires careful handling and treatment. This residue, which contains over 38% iron, has the potential to be an alternative raw material for the iron and steel industry. However, the direct use of this residue as a burden material in the steel industry faces challenges due to the substantial presence of sulfur, which exceeds 1%. In the pursuit of sustainability within the iron and steel sector, researchers have increasingly focused on advancing hydrogen plasma technology. Laboratory tests were conducted on the treatment of the leaching residue exposed to hydrogen plasma smelting reduction. The results revealed that within just 5 s of exposure to hydrogen plasma, the transformation of the residue into metal was initiated. After 30 s of exposure, the formation of metal had already occurred, but the sulfur content remained above 0.5%. However, when the residue was exposed to hydrogen plasma for 180 s, the sulfur content in the metal decreased to less than 0.1%. The presence of nickel and chromium in the resulting metal products should be taken into consideration, especially when special steels or stainless steel are being produced.

Stock market response to natural disasters: Does corporate sustainability performance make difference?

This study aims to examine the short-term price reactions of the stocks listed on Borsa Istanbul (BIST) after the severe earthquake of February 6, 2023, that happened in the southeastern region of Türkiye covering 11 provinces and causing more than 50,000 fatalities. Using a sample of 450 companies listed on the BIST All Index, this study estimates the abnormal returns (ARs) of stocks by employing an event study methodology. Using BIST 100 companies as a sub-sample, this study also explores whether sustainability performance creates resilience against downside risk after the earthquake. The results of the market model and the mean-adjusted model show that on the event day, most of the sectors had negative and significant ARs, while only the non-metal mineral products had positive and significant ARs. Most of the sectors continued to decline in the following 10 days except basic metal and non-metal mineral products sectors. The telecommunications sector was the most negatively affected sector in both models after the event day as it has underperformed in ensuring uninterrupted access to communication. The findings also indicate that firms in the financial sector that have higher sustainability performance are more resilient in responding to the disaster.