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In this research, four industrial wastes were used for up to 80% as supplementary cementitious materials (SCMs) in cement mortar systems: ground granulated blast furnace slag, electric arc furnace slag, basic oxygen furnace slag, and waste limestone powder. Quaternary cementitious blends were prepared and studied for up to 120 days. Workability, compressive strength, durability, microstructures, and sustainability studies were performed and compared with Portland cement references. Results showed that more than 30 MPa in compressive strength can be achieved by > 50% replacement with SCMs; only 9% below the reference. Neither H2SO4 nor MgSO4 attacks resulted in critical damages; nevertheless, curing under NaCl solution showed detrimental behavior. C-S–H with a low Ca/Si ratio was identified in the mortars as the main hydration product, possibly intermixed with stratlingite, C-A-S–H and/or hydrotalcite. Environmental impact for the blended cements was determined as the CO2eq. factor from a simple life cycle assessment. The embodied greenhouse gasses varied in 260.2–541.4 kg CO2eq./ton of binder depending on the formulation. This was 40–70% less than Portland cement (922.6 kg CO2eq./ton). The production of the raw materials dominated the polluting emissions, while freight, grinding, and sieving had little environmental impact. [ABSTRACT FROM AUTHOR]

In this article, a brief review of the development of the Knudsen effusion mass spectrometric (KEMS) approach in the Theoretical Metallurgy Department of the KTH Royal Institute of Technology and in the in the Laboratory of Metallurgy of the Helsinki University of Technology and modifications of quadrupole model QMG420 mass spectrometers, is presented. The thermodynamic data obtained from vaporization of standards, such as NaCl, CsCl, B2O3, and Ag, and of the B2O3–Al2O3 and ZnO–P2O5 systems is compared with the data obtained using a magnetic MS1301 mass spectrometer. For the first time, composition of the vapor phase over the Dy2O3–DyF3, CaO–CaCl2, and Cu–Mg systems and the partial pressures of components at high temperatures are investigated. The experimental data obtained for the investigated systems are used for prediction of the vaporization processes and modeling of thermodynamic properties and high‐temperature phase equilibria in the multicomponent systems used in metallurgy. An account is given of the detailed studies of the vaporization processes and thermodynamic properties of some multicomponent systems composed of oxides, fluorides, and carbonates forming mold powders for continuous casting of steel. Some new directions of the ongoing studies by the KEMS method are summarized. [ABSTRACT FROM AUTHOR]

Zeolites have been increasingly applied in various fields such as energy conversion, environmental remediation, chemical production, and so on, being used as membranes, catalysts, and supports due to their large specific areas and strong gas adsorption. And, developing low-cost strategies for the preparation of zeolites has attracted the extensive attention of researchers. Coal fly ash, waste glass, discard zeolites, and slags are typical industrial wastes and rich in Si and Al, indicating that these industrial wastes can be utilized as alternative raw materials of zeolite synthesis. Firstly, the chemical composition and properties of these industrial wastes are summarized. Then, the strategies involved in synthesizing different zeolites from various industrial wastes are discussed. In addition, the applications of these zeolites are comprehensively reviewed. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the mineralogical and chemical composition of zinc and lead metallurgical slags. These slags contain numerous elements, including toxic metals, which form conglomerates or multiphase intergrowths. The phase composition of slags is one of the main factors that determine their behaviour in weathering environments, that is, their ability to release metals when exposed to atmospheric factors. In this paper, the release of elements from slags and their mobility in a hypergenic environment is determined based on the results of leachability tests and on geochemical modelling, thus assessing the environmental impact of landfilled slags. The elements released from slags in the largest quantities are zinc and lead. Zn is leached out over a long period of time. It was found that after 12 years, the concentration of Zn in the eluate exceeds by 40 times the permissible value of 200 mg/kg for hazardous waste. The degree of leaching of lead from slags as a function of time (after 12 years), despite its significant solubility in water, is much lower than the degree of leaching of zinc. The most mobile phase components of slags in the studied hypergenic environment are the lead phases (anglesite and galena) and, to a lesser extent, the zinc phases (sphalerite and willemite). Anglesite and galena in almost the entire Eh-pH range, along with admixtures of elements, decompose into ionic forms: PbCl42−, Pb2+, and PbOH+. Sphalerite in the soil and water environment (oxidizing and acidic conditions) will decompose into the mobile ionic form Zn2+. Willemite, which is resistant to weathering, will undergo similar decomposition. It can therefore be assumed that the carriers of toxic metals are primarily lead sulphides and sulphates, zinc sulphides, and, less frequently, zinc, lead, and iron oxides. [ABSTRACT FROM AUTHOR]

A fundamental analysis is presented to describe the dissolution behavior of lime (CaO) in FeO-containing slags. FeO present in steelmaking slag is seen to penetrate preferentially into the lime particle and form a (CaO–FeO) layer around it, thereby a pathway for outward diffusion of CaO into the slag and subsequent formation of dicalcium silicate. In the present work, the lime dissolution behavior is described in terms of the chemical potential gradient of CaO between the lime particle and slag. The chemical potential gradient is more fundamental for calculating fluxes in concentrated melts in which the activities are far from ideal, which has been ignored by previous researchers. The model developed in the present work is used to compare the mass transfer coefficients for a variety of experimental conditions. In addition, other factors affecting the dissolution are lime particle morphology, activity of silica in slag, slag viscosity, temperature and turbulence in slag. [ABSTRACT FROM AUTHOR]

Ferromanganese crusts are mineral resources distributed in the planet's oceans. These deep-sea minerals stand out for their abundance and diversity of metals, with Mn and Co being the most abundant elements. These minerals are a good alternative to diversify the extraction of elements, which today are found at low grades on the Earth's surface. For the co-processing of ferromanganese crusts to recover Co and Mn, there are few studies. These generally worked with the use of a reducing agent, and in many cases previous roasting processes. In the present investigation, two ferromanganese crusts that were collected from two seamounts in the central eastern Atlantic Ocean were characterized. Subsequently, these crusts were leached in an acid-reducing medium, adding steel waste (slag) with 99.73% Fe3O4 and 0.27% metallic iron from the steel industry as a reducing agent. Acid-reducing processes have previously been shown to yield high and rapid recoveries of Co and Mn from seabed minerals. However, there is no previous study using smelting slag as a reducing agent for the treatment of ferromanganese crusts. The best results of this research were obtained when working at 60 C, achieving joint extractions of Co and Mn of ~80% and ~40%, respectively, in 10 min. In addition, the process residues were analyzed, and the formation of contaminating elements or the precipitation of Co and Mn species was not observed. [ABSTRACT FROM AUTHOR]

The production of wood composite materials and, in particular, plywood is one of the most effective ways to utilize waste in order to increase the recycling of by-products. The purpose of the work was to study the possibility of using steelmaking acidic slag as a modifying additive in urea–formaldehyde resins for plywood production and to determine the effect of steelmaking slag on the strength of plywood adhesive joints. The main sources of slag are the oxidation products of cast iron and scrap impurities (silicon, manganese, phosphorus, chromium, etc.), charge materials (lime, limestone, iron and manganese ore, scale, bauxite, fluorspar, etc.), and products of the destruction of refractory linings. As a result of the study, it has been found that the introduction of lignosulfonates, kaolin, and slags into urea–formaldehyde resin increases the reactivity of the finished glue. The ability of metal oxides in slag to bind hydroxyl groups has been proven; in this regard, when heated during pressing, the polymer does not break down into simple monomers, and the free formaldehyde of the urea–formaldehyde resin enters into a polycondensation reaction and is not evaporated from the glue. [ABSTRACT FROM AUTHOR]

The Shu Commandery was an important iron production center in southwest China during the Han Dynasty (202 BC‐AD 220). In 2007, archaeologists excavated a Han Dynasty smelting furnace (L1) at the Gushishan site and collected large amounts of smelting remains including slags, furnace bricks, and ores. Scientific analysis of the excavated slags was carried out to ascertain that the Gushishan site was a pig iron smelting site. No flux was used at the Gushishan site, and the site is dated no later than the Eastern Han period. No remains related to iron casting of the Han Dynasty was found at or near the iron smelting sites in southwest China, which indicates a separation between iron smelting and iron casting as characteristics of the industrial layout in this region. [ABSTRACT FROM AUTHOR]

The surface tensions of molten oxides depend strongly on the structural relaxation of the surface region. The mechanism of surface structural relaxation for molten oxide slags is complex. The surface tension of calcium aluminate slag is minimal at an intermediate composition, although the critical reason has not been identified. Here, two novel approaches were used to evaluate the features of surface ionic structures in the molten state for the range of 25–50 mol% Al2O3: (1) X‐ray absorption analysis of oxygen and cationic elements in glass samples after surface relaxation treatment, and (2) molecular dynamics simulations, based on a polarizable‐ion model, of the ionic distribution in a molten slag with vacuum/melt interfaces. The results indicate that bridging oxygen (BO) ions are preferred to non‐BOs in the surface region. In calcium aluminate slag, BOs are formed by connecting two AlO4 tetrahedrons with charge compensation of two Al3+ ions with one Ca2+ ion. Additionally, the above approaches were used to qualify the effect on the surface ionic structure of adding 1–20 mol% SiO2 to the calcium aluminate slag. The results indicated that the SiO4 tetrahedrons incorporate the vertex connection with AlO4 tetrahedrons to form BOs in the surface region. [ABSTRACT FROM AUTHOR]

The Mazarrón 2 shipwreck was found in 1994 on the beach of Playa de la Isla (Mazarrón, Murcia, Spain). This finding is extremely important because the boat and its lead cargo were still in a reasonable conservation state and, therefore, provided new data on naval construction, commercial goods, navigation routes, and the relationships between the Phoenicians and the local population in the 7th–6th century BC. Currently, the shipwreck remains underwater, protected by a metallic coffer. In the last 2 years, a Preliminary Studies Project has been carried out, supported by national and regional public institutions. This research aims to know the shipwreck's conservation state and to determine the extraction and conservation methods at the Museo Nacional de Arqueología Subacuática ARQVA (Cartagena, Spain), where the conservation and restoration treatment will be conducted. The sampling strategy and analytical study included not only wood and other materials from the shipwreck and its cargo but also the seawater and the seabed materials in the vicinity of the shipwreck. This paper presents the results of the geochemical study of the archeological site. The applied methodology included physico-chemical tests, X-ray diffraction, optical microscopy, FTIR spectroscopy, field-emission scanning electron microscopy coupled with X-ray microanalysis, and X-ray microscopy. The results indicated that, despite the wreck being buried at a shallow depth (less than 50 cm) in a marine environment with a water column of 2–2.5 m, influenced by complex coastal dynamics that favor an oxic environment, early diagenetic processes like the formation of pyrite framboids are particularly intense in the pores and internal channels of the wreck's wood, where a different dysoxic–anoxic environment prevails. These processes have been the main mechanisms to have affected the wreck and are related to the biogeochemistry of sediments. The sediments have been confirmed to be closely related to the geological context of the Mazarrón region. The conducted study found no significant evidence of pollution due to the lead cargo. [ABSTRACT FROM AUTHOR]

Abstract The study assessed the uniformity of the metallurgical process carried out during the period of Roman influence in Poland. The age of the investigated material was confirmed based on an analysis of the 12C/14C isotope ratio in the charcoal found in slag. The comparison was based on four Holy Cross Mountains (Poland) locations. The evaluation included smelting temperature, viscosity of the metallurgical melt, oxidation–reduction conditions, and slag cooling rate determined based on geochemical (XRF) and mineralogical (XRD, SEM, EPMA) analyses. Despite the distance between individual sampling sites, the conditions in which smelting was carried out were similar for all samples. The liquidus temperature of the analyzed slags was in the range of 1150–1200 °C. Oxidation–reduction conditions were determined through thermodynamic calculations using SLAG software. In the temperature range of 1150–1200 °C, the oxygen fugacity had to be below logP O2 = − 13.20 to − 12.53 atm to reduce iron oxides to metallic iron. The viscosity of the metallurgical melt was calculated and ranged from 0.15 to 1.02 Pa s, indicating a low viscosity. The slag cooling rate determined based on olivine morphology was in the range of > 5 to 300 °C/h. Smelting parameters were compared with other locations in Poland, and similar results were obtained for slags from Masovia and Tarchlice. In the case of one site (Opole), despite the higher maximum value of liquidus temperature, it was indicated that the process could have taken place in similar conditions, and the differences resulted from contamination of the slag with material from the furnace/pit walls.

The fine particles around a mining area are easy to transport under the climatic and hydrological actions such as rainfall, that causes the change in the permeability of accumulated slag and increases the hazard probability of slag debris flow. In this study, eight experiments were designed to discuss the influence of fine particle migration on the permeability characteristics and clogging of slag accumulation in different graded particles and different dry densities. The results of experiments with coarse slags of five different particle sizes show that the ratio ranging from four to six in the coarse slag size and fine size caused a significant clogging phenomenon. It is confirmed that the shape of the particles is one of the factors affecting the clogging of coarse soil besides the coarse and fine particle size, and the clogging assessment criterion for slag and the corresponding clogging patterns based on the slag shape characteristics are given. And through three kinds of different dry density-graded slag, three clogging experiments were completed to verify the clogging standard and clogging particle size. The experimental results show that the clogging particle size obtained by the clogging criteria can effectively reduce the permeability of slag accumulation, and it is considered that the equivalent particle size and particle shape characteristics are the main factors affecting the clogging performance of accumulation, while the dry density of deposits has no significant influence on it. [ABSTRACT FROM AUTHOR]

The study assessed the uniformity of the metallurgical process carried out during the period of Roman influence in Poland. The age of the investigated material was confirmed based on an analysis of the 12C/14C isotope ratio in the charcoal found in slag. The comparison was based on four Holy Cross Mountains (Poland) locations. The evaluation included smelting temperature, viscosity of the metallurgical melt, oxidation–reduction conditions, and slag cooling rate determined based on geochemical (XRF) and mineralogical (XRD, SEM, EPMA) analyses. Despite the distance between individual sampling sites, the conditions in which smelting was carried out were similar for all samples. The liquidus temperature of the analyzed slags was in the range of 1150–1200 °C. Oxidation–reduction conditions were determined through thermodynamic calculations using SLAG software. In the temperature range of 1150–1200 °C, the oxygen fugacity had to be below logP O2 = − 13.20 to − 12.53 atm to reduce iron oxides to metallic iron. The viscosity of the metallurgical melt was calculated and ranged from 0.15 to 1.02 Pa s, indicating a low viscosity. The slag cooling rate determined based on olivine morphology was in the range of > 5 to 300 °C/h. Smelting parameters were compared with other locations in Poland, and similar results were obtained for slags from Masovia and Tarchlice. In the case of one site (Opole), despite the higher maximum value of liquidus temperature, it was indicated that the process could have taken place in similar conditions, and the differences resulted from contamination of the slag with material from the furnace/pit walls. [ABSTRACT FROM AUTHOR]

Towards the end of the 19th century and the early 20th century, France was the world's largest producer of antimony, especially due to the rich deposits in the Brioude‐Massiac area. Even though all the mining and smelting activities are long gone, there are still some remains of those activities. The most original of those is the use of roasting slags as aggregates in former plant walls or industrial building. They are macroscopically characterised by a black or red colour with a vesicular aspect similar to natural pozzolanas. Common petrography and mineralogy tools have been used to characterise those slags: optical mineralogy, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM‐EDS) and X‐ray diffraction (XRD). To gain an insight into their mineral complexity, a QEMSCAN map has been produced. The mineralogy is typical of high‐temperature slags: cristobalite, quartz, mullite, fayalite‐forsterite series and spinel. The antimony content is quite high, up to seven percent, under the form of various antimony oxides and native antimony. LAY DESCRIPTION: In the Brioude‐Massiac area, France, antimony has been heavily mined at the end of the 19th century, giving rise to the generation of large amounts of wastes from the metallurgy of the ores. Those wastes (scoria and slags) have been used locally as aggregates to build walls. They consist of high‐temperature phases (SiO2 polymorphs: cristobalite and tridymite, dendritic spinel, glass) and illustrate an early example of the reuse of waste materials, nowadays termed as 'circular economy'. [ABSTRACT FROM AUTHOR]

TiO2 inclusion formation in the weld pool is required to produce potent nucleation sites for acicular ferrite microstructure formation. Weld metal oxygen content must be limited to ensure acceptable materials properties, although sufficient oxygen is required for inclusion formation. Weld pool oxygen is sourced from the decomposition of flux oxides. Weld metal oxygen is controlled with flux chemistry formulation by CaF2 dilution of oxides. In conventional submerged arc welding (SAW), the flux is the source of weld metal Ti. Transfer of Ti from the slag appears to be limited to 400 parts per million (ppm). SAW modification by metal powder additions changes the element transfer reactions. Thermochemical analysis is applied to explain the limitations in Ti transfer from the slag, compared to improved reaction conditions for Ti element transfer in the aluminum‐assisted Ti alloying of weld metal. Low TiO2 activity due to low flux TiO2 content from CaF2 dilution and Ti loss from Ti‐fluoride gas formation limits Ti transfer from slag. Aluminum‐assisted alloying of the weld metal shifts the gas composition from Ti‐fluoride formation to Al‐fluoride formation and lowers the system partial oxygen pressure to increase the weld metal Ti content, with acceptable ppm O remaining in the weld metal. [ABSTRACT FROM AUTHOR]

The thermophysical properties of an industrial blast furnace slag with varying TiO2, V2O3, and FeOx content are investigated using a rotating viscometer and maximum bubble pressure method at low oxygen partial pressure. The obtained experimental results are supported by thermodynamic calculations using FactSage 7.2 software and by scanning electron microscope analysis. The measurement outcomes clearly indicate that an increase in V2O3 and TiO2 content up to 10 wt% at 5 wt% FeOx leads to a decrease in the viscosity of all studied slags; however, with 15 wt% of V2O3 and TiO2, the viscosity changes insignificant. The presence of 10 wt% FeOx alters the behavior of the slags in the liquid‐dominant region. These changes in the break point temperature are consistent with the behavior of melilite and perovskite phases. Moreover, an increase in the FeOx, V2O3, and TiO2 increases the density of all studied slags within the temperature range of 1450–1650 °C. Additionally, introducing pure oxides to the slag reduces the surface tension of all the studied slags, confirming their role as a surfactant. [ABSTRACT FROM AUTHOR]

Abstract The study presents the first use of predominance area diagrams (PADs) to determine oxidation–reduction conditions during reconstructing historical copper smelting processes. The smelting temperature and oxygen and sulfur fugacities during smelting were determined based on experiments and the geochemical (ICP-MS/ES, XRF) and mineralogical (SEM, EPMA) analyses of the fifteenth to seventeenth century slags from Polichno (Holy Cross Mountains, Poland). Results obtained during high-temperature experiments allowed to determine the slags' solidus and liquidus temperatures. The liquidus temperature was in the range of 1100–1200 °C, and the solidus temperature was in the range of 800–1100 °C. Data on temperature conditions were used in thermodynamic calculations to construct predominance area diagrams and then to determine the ranges of oxygen and sulfur fugacities in which the formation of slags was possible. Slags from Polichno were formed with the oxygen fugacity in the range of $$\text{logP}_{{\text{O}}_2}$$ logP O 2 = − 4.30 (POL1, POL4 at 1200 °C) to − 14.08 atm. (POL3 at 1090 °C). In turn, the sulfur fugacity during slag formation ranged from $$\text{logP}_{{\text{S}}_2}$$ logP S 2 = − 2.50 (POL5 at 1200 °C) to − 6.92 (POL4 at 1060 °C) atm. The relatively high sulfur availability confirms using sulfide ores without prior roasting. The wide range of sulfur and oxygen fugacity indicates the process's heterogeneity.

Ferromanganese crusts are mineral resources distributed in the planet’s oceans. These deep-sea minerals stand out for their abundance and diversity of metals, with Mn and Co being the most abundant elements. These minerals are a good alternative to diversify the extraction of elements, which today are found at low grades on the Earth’s surface. For the co-processing of ferromanganese crusts to recover Co and Mn, there are few studies. These generally worked with the use of a reducing agent, and in many cases previous roasting processes. In the present investigation, two ferromanganese crusts that were collected from two seamounts in the central eastern Atlantic Ocean were characterized. Subsequently, these crusts were leached in an acid-reducing medium, adding steel waste (slag) with 99.73% Fe3O4 and 0.27% metallic iron from the steel industry as a reducing agent. Acid-reducing processes have previously been shown to yield high and rapid recoveries of Co and Mn from seabed minerals. However, there is no previous study using smelting slag as a reducing agent for the treatment of ferromanganese crusts. The best results of this research were obtained when working at 60 C, achieving joint extractions of Co and Mn of ~80% and ~40%, respectively, in 10 min. In addition, the process residues were analyzed, and the formation of contaminating elements or the precipitation of Co and Mn species was not observed.

The study presents the first use of predominance area diagrams (PADs) to determine oxidation–reduction conditions during reconstructing historical copper smelting processes. The smelting temperature and oxygen and sulfur fugacities during smelting were determined based on experiments and the geochemical (ICP-MS/ES, XRF) and mineralogical (SEM, EPMA) analyses of the fifteenth to seventeenth century slags from Polichno (Holy Cross Mountains, Poland). Results obtained during high-temperature experiments allowed to determine the slags' solidus and liquidus temperatures. The liquidus temperature was in the range of 1100–1200 °C, and the solidus temperature was in the range of 800–1100 °C. Data on temperature conditions were used in thermodynamic calculations to construct predominance area diagrams and then to determine the ranges of oxygen and sulfur fugacities in which the formation of slags was possible. Slags from Polichno were formed with the oxygen fugacity in the range of logP O 2 = − 4.30 (POL1, POL4 at 1200 °C) to − 14.08 atm. (POL3 at 1090 °C). In turn, the sulfur fugacity during slag formation ranged from logP S 2 = − 2.50 (POL5 at 1200 °C) to − 6.92 (POL4 at 1060 °C) atm. The relatively high sulfur availability confirms using sulfide ores without prior roasting. The wide range of sulfur and oxygen fugacity indicates the process's heterogeneity. [ABSTRACT FROM AUTHOR]

The EU steel industry accounts for a crude steel production of 140 Mt/y, provided by the integrated (57%) and electric (43%) routes, which respectively require up to 6.0 and 0.6 MWh/tCrudeSteel of energy input, and emits on average 1.85 and 0.4 tCO2/tCrudeSteel. The mitigation of such CO2 emissions is crucial, and would involve the direct avoidance of carbon, improvement of energy efficiency, and carbon capture. However, the environmental burden of the steel industry cannot be limited to this, given the very large amount (approximately 5 Mt) of residues landfilled every year in the EU. This practice cannot be sustained anymore, since it represents a detrimental waste of resources and burden to the environment. These aspects require prompt action to meet the Green Deal goals envisioned for 2030. This review paper aims to provide an overview of the main state-of-the-art technologies commercially (and not) available for the effective treatment of a wide variety of residues. To enrich this overview with further potential candidates towards a more sustainable steel manufacturing process, the combined application of two technologies (a plasma reactor and a RecoDust unit for the recovery of metals and minerals, respectively) at TRL 5-6 is also investigated here. [ABSTRACT FROM AUTHOR]

Currently, the common way for structural investigation is to confirm the amorphous state of the quenched slag by XRD prior to Raman analysis. However, if the slag precipitates a few nanocrystals during quenching, XRD may not recognize them, but the slag structure has been changed. Therefore, this paper proposes to combine TEM with XRD and Raman for analyzing the slag structure and to verify it with blast furnace slag obtained by different quenching methods. The results show that the XRD curves of the slags obtained by quenching in water or on a stainless steel plate show amorphous states, but the deconvolution results of Raman spectra are significantly different. The TEM analysis finds a few crystals in the slag obtained by the latter, which is responsible for the structural differences. Therefore, it is necessary to confirm the amorphous state of the slag by both XRD and TEM before studying the structure. [ABSTRACT FROM AUTHOR]

Iron and steel together with the cement sector are the largest industrial CO2 emitters and pressure is mounting to reduce these emissions. For the iron and steel industry a shift from coal fired blast furnace to hydrogen based direct reduction, electrification via the electric arc furnace (EAF) and off‐setting with CCUS are today the most promising pathways. The iron and steel industry today is almost a closed cycle industry, where all by‐products from steel production can be recycled or used for further applications. Most of the slags that are generated in ironmaking are used as granulated blast furnace sand for cement production, hence landfilling of such slags has been largely eliminated. For steelmaking slags and dusts, different treatment and modification solutions have been developed and are in use. Still a certain part of these by products is not fully utilized. Green transition of the steel sector with less blast furnace and more direct reduction in operation will have a significant impact on the slags and by‐products generated in future. For a sustainable transition, circularity is a key aspect and slags will have to remain a secondary feed stock for the cement sector. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the mineralogical and chemical composition of zinc and lead metallurgical slags. These slags contain numerous elements, including toxic metals, which form conglomerates or multiphase intergrowths. The phase composition of slags is one of the main factors that determine their behaviour in weathering environments, that is, their ability to release metals when exposed to atmospheric factors. In this paper, the release of elements from slags and their mobility in a hypergenic environment is determined based on the results of leachability tests and on geochemical modelling, thus assessing the environmental impact of landfilled slags. The elements released from slags in the largest quantities are zinc and lead. Zn is leached out over a long period of time. It was found that after 12 years, the concentration of Zn in the eluate exceeds by 40 times the permissible value of 200 mg/kg for hazardous waste. The degree of leaching of lead from slags as a function of time (after 12 years), despite its significant solubility in water, is much lower than the degree of leaching of zinc. The most mobile phase components of slags in the studied hypergenic environment are the lead phases (anglesite and galena) and, to a lesser extent, the zinc phases (sphalerite and willemite). Anglesite and galena in almost the entire Eh-pH range, along with admixtures of elements, decompose into ionic forms: PbCl42−, Pb2+, and PbOH+. Sphalerite in the soil and water environment (oxidizing and acidic conditions) will decompose into the mobile ionic form Zn2+. Willemite, which is resistant to weathering, will undergo similar decomposition. It can therefore be assumed that the carriers of toxic metals are primarily lead sulphides and sulphates, zinc sulphides, and, less frequently, zinc, lead, and iron oxides.

Abstract The Incas appropriated many local metallurgical technologies throughout the Andes, each of which had its unique peculiarities and was based on local ancestral knowledge. The widespread use of tin-bronze during the Inca expansion, the development of mining and smelting sites, as well as ethno-historical records evidence the Incas’ interest in copper smelting, a key activity in the Andes since ca. 1400 BC. However, little is known about the technical parameters achieved by ancient metallurgists and the changes that occurred during the Inca expansion. In this paper, we address these changes through a case study of Copiapó valley, focusing on the Viña del Cerro site, one of the most famous Inca smelting centres of the southern Andes. Although this place was architectonically restructured by the Incas, its operations began long before the imperial expansion and used wind-powered furnaces. We analysed 19 slag and 11 copper ore samples using OM, SEM–EDS, WD-XRF, and XRD analyses. Results identified heterogeneous and viscous slags, rich in SiO2 (43 wt%) and poor in FeO (13 wt%). Copper retention was high (up to 60 wt%). Microstructural analyses indicate that slags were formed under unstable oxidising conditions, reaching temperatures that ranged between 1000 to 1100 °C. The copper produced was very pure. High-grade copper ores containing up to 69 wt% CuO were reduced at the site, combining carbonates (malachite, azurite), halides (buttgenbachite, clinoatacamite), and some sulphates (brochantite). We propose that even under the relatively unfavourable conditions for slag formation, the smelting conditions generated at Viña del Cerro were competent enough to extract metal, but not necessarily enough to form liquid slag. These conditions were facilitated by the local metallurgists’ thorough knowledge of the wind flow and their ability to select the right ore. This new information contributes to understanding the efficiency of metallurgical technology and the knowledge, skills, and adaptability of the ancient metallurgists from Copiapó valley, a group that was integrated into the economic networks of the Inca Empire.

Rapid industrialization and urbanization in emerging nations have resulted in the accumulation of various industrial wastes. As a result, reusing and recycling these wastes into an economical, durable, and environmentally friendly building material may be the most effective means of mitigating their environmental impact. Such wastes are being dumped in greater quantities, which pollute the ecosystem and the land. As a result, its efficient use and management are required, which presents a global issue for its viable recycling and safe disposal. The current review examines the use of various slags, including cupola slag, electric arc furnace slag (EAFS), steel furnace slag (SFS), and ground granulated blast furnace slag (GGBFS) in the development of sustainable construction materials considering the potential of such waste in greener concrete composites towards eco-friendly infrastructure. In order to produce environmentally acceptable construction materials, these waste slags have been used as a partial and full replacement of cement, fine and coarse aggregate with or without supplementary materials ranging from 10 to 60% for cupola slag, 20 to 50% for EAFS, 10 to 50% for GGBFS, and 10 to 30% for SFS are suggested. This review will be an inclusion that helps readers to identify gaps in experimental viability, material characterization, and physico-mechanical behaviour of waste slags, pointing to the potential for application in the production of sustainable building materials.

The fine particles around a mining area are easy to transport under the climatic and hydrological actions such as rainfall, that causes the change in the permeability of accumulated slag and increases the hazard probability of slag debris flow. In this study, eight experiments were designed to discuss the influence of fine particle migration on the permeability characteristics and clogging of slag accumulation in different graded particles and different dry densities. The results of experiments with coarse slags of five different particle sizes show that the ratio ranging from four to six in the coarse slag size and fine size caused a significant clogging phenomenon. It is confirmed that the shape of the particles is one of the factors affecting the clogging of coarse soil besides the coarse and fine particle size, and the clogging assessment criterion for slag and the corresponding clogging patterns based on the slag shape characteristics are given. And through three kinds of different dry density-graded slag, three clogging experiments were completed to verify the clogging standard and clogging particle size. The experimental results show that the clogging particle size obtained by the clogging criteria can effectively reduce the permeability of slag accumulation, and it is considered that the equivalent particle size and particle shape characteristics are the main factors affecting the clogging performance of accumulation, while the dry density of deposits has no significant influence on it.

The Incas appropriated many local metallurgical technologies throughout the Andes, each of which had its unique peculiarities and was based on local ancestral knowledge. The widespread use of tin-bronze during the Inca expansion, the development of mining and smelting sites, as well as ethno-historical records evidence the Incas' interest in copper smelting, a key activity in the Andes since ca. 1400 BC. However, little is known about the technical parameters achieved by ancient metallurgists and the changes that occurred during the Inca expansion. In this paper, we address these changes through a case study of Copiapó valley, focusing on the Viña del Cerro site, one of the most famous Inca smelting centres of the southern Andes. Although this place was architectonically restructured by the Incas, its operations began long before the imperial expansion and used wind-powered furnaces. We analysed 19 slag and 11 copper ore samples using OM, SEM–EDS, WD-XRF, and XRD analyses. Results identified heterogeneous and viscous slags, rich in SiO2 (43 wt%) and poor in FeO (13 wt%). Copper retention was high (up to 60 wt%). Microstructural analyses indicate that slags were formed under unstable oxidising conditions, reaching temperatures that ranged between 1000 to 1100 °C. The copper produced was very pure. High-grade copper ores containing up to 69 wt% CuO were reduced at the site, combining carbonates (malachite, azurite), halides (buttgenbachite, clinoatacamite), and some sulphates (brochantite). We propose that even under the relatively unfavourable conditions for slag formation, the smelting conditions generated at Viña del Cerro were competent enough to extract metal, but not necessarily enough to form liquid slag. These conditions were facilitated by the local metallurgists' thorough knowledge of the wind flow and their ability to select the right ore. This new information contributes to understanding the efficiency of metallurgical technology and the knowledge, skills, and adaptability of the ancient metallurgists from Copiapó valley, a group that was integrated into the economic networks of the Inca Empire. [ABSTRACT FROM AUTHOR]

A kinetic model based on the double‐film theory is developed to predict the composition‐change behavior of Ti‐bearing steel and slag during the slag‐liquid steel reaction process and validated by experimental results. The chemical reactions between the slag‐metal, slag‐crucible refractory, and metal‐crucible refractory are considered. Specifically, a coupled reaction model based on the CaO–MgO–CaF2–SiO2–Al2O3–TiO2–FeO–MnO and Fe–Si–Al–Ti–Ca–Mg–Mn–S–O systems is applied to describe the reaction between liquid steel and slag. Furthermore, the activity coefficients of slag components are calculated using the ion and molecular coexistence theory model. The reaction between the slag and refractory is described using an empirical equation. The reaction between the liquid steel and refractory is described using a coupled reaction model, wherein the reaction between [Al] and MgO is considered. Finally, the effect of (TiO2) on the [Ti] is discussed using this model. The results indicate that the [Ti] decreases, the [Si] increases, and the [Al] increases initially and subsequently decreases with reaction time. An increase in (TiO2) can decrease the oxidation of [Ti] by (SiO2) and (Al2O3). When the (TiO2) increases, the mass ratio of CaO to SiO2 should be further increased to decrease the oxidation of [Ti]. [ABSTRACT FROM AUTHOR]

This study presents the first reconstruction of the smelting conditions in 16th‐ to 18th‐century smelters from Miedziana Góra (Holy Cross Mountains, Poland). Based on geochemical (inductively coupled plasma mass spectrometry/emission spectrometry, X‐ray fluorescence) and mineralogical analysis (X‐ray diffractometry, scanning electron microscopy, electron probe micro‐analysis) of historical slags, their chemical/phase composition and the basic smelting parameters (temperature, melt viscosity, and oxygen fugacity) were determined. Due to the differences in chemical and phase composition, slags from different smelting stages have been distinguished: hypocrystalline slags (MG6) from speiss/matte production and glassy (MG1–MG5) from matte conversion. In glassy slags, pyroxenes, quartz/cristobalite grains, and aggregates composed of metallic Cu and PbO are dispersed in the glass. Hypocrystalline slags are composed of wollastonites, anorthites, and metallic Cu. The temperature range at which the slags were formed was from ~1100°C (solidus temperature) to 1150–1200°C (liquidus temperature). The silicate melt's viscosity was from log η = 1.19 to 4.42 Pa s (at 1100–1200°C). The higher viscosity of MG1–MG5 slags indicates that, unlike MG6 slags, they were not formed during gravity separation. Information about the phase composition made it possible to determine the oxygen fugacity in the range of log fO2 = −4 to −12 atm. High oxygen fugacity indicates the oxidizing nature of the smelting process. [ABSTRACT FROM AUTHOR]

Slags fromthe remoteMota Farun locality above Casaccia (Val Bregaglia, Swiss Alps) have been analyzed with scanning electron microscopy, X-ray powder diffraction and microfocus synchrotron X-ray diffraction to determine mineralogical composition and microstructures. Non-magnetic slag samples are largely composed of euhedral and dendritic iron-rich olivine in a glassy matrix. Locally there are zones with globular inclusions rich in bornite ((Cu5Fe)S4) and locally metallic copper. Some regions display dendritic pentlandite ((Fe,Ni)9S8). Magnetic samples are mainly composed of fayalite (Fe2SiO4) and wüstite (FeO), with minor magnetite (Fe3O4). The mineralogical composition indicates that slags were the product of copper smelting. The slag compositions andmorphologies are analogous to slags described from the Oberhalbstein (Graubünden, Switzerland) and the Trentino Alps (Italy) which are attributed to metallurgical exploitations of the Late Bronze Age. While the origin of the ore could not be determined, it may be related to ore deposits of chalcopyrite in greenschists and serpentinites in the vicinity, such as Alp Tgavretga (Septimer Pass) and Val Perossa (Val Bregaglia).

Slags fromthe remoteMota Farun locality above Casaccia (Val Bregaglia, Swiss Alps) have been analyzed with scanning electron microscopy, X-ray powder diffraction and microfocus synchrotron X-ray diffraction to determine mineralogical composition and microstructures. Non-magnetic slag samples are largely composed of euhedral and dendritic iron-rich olivine in a glassy matrix. Locally there are zones with globular inclusions rich in bornite ((Cu5Fe)S4) and locally metallic copper. Some regions display dendritic pentlandite ((Fe,Ni)9S8). Magnetic samples are mainly composed of fayalite (Fe2SiO4) and wüstite (FeO), with minor magnetite (Fe3O4). The mineralogical composition indicates that slags were the product of copper smelting. The slag compositions andmorphologies are analogous to slags described from the Oberhalbstein (Graubünden, Switzerland) and the Trentino Alps (Italy) which are attributed to metallurgical exploitations of the Late Bronze Age. While the origin of the ore could not be determined, it may be related to ore deposits of chalcopyrite in greenschists and serpentinites in the vicinity, such as Alp Tgavretga (Septimer Pass) and Val Perossa (Val Bregaglia).

Owing to the complexity of the multivalence states of vanadium oxides in slag systems and experimental difficulties, thermodynamic properties of vanadium oxides have not been established yet. In the present study, the mixed‐valence states and activities of the vanadium oxides in CaO–SiO2–VOx slag were investigated experimentally at 1873 K and oxygen partial pressures of 3.2 × 10–9 and 3.1 × 10–7 atm. After the CaO–SiO2–VOx slag had equilibrated with a platinum strip, the mixed‐valence states of the vanadium oxides in the slag were estimated by performing X‐ray photoelectron spectroscopy, and the activities of the vanadium oxides in the slag were calculated using the activity of vanadium in the platinum strip at equilibrium using thermodynamic equations. At an oxygen partial pressure of 3.2 × 10–9 atm, V3+ was the dominant ion and V4+ was the second most abundant ion. With increasing VOx content or basicity (CaO/SiO2 ratio), the fraction of V3+ decreased, whereas that of V4+ increased. The activity of VO1.5 was greater than those of the other vanadium oxides. On the other hand, when the oxygen partial pressure increased to 3.1 × 10–7 atm, V4+ became the dominant ion. As the slag basicity increased, the fraction of V4+ increased further, whereas that of V3+ decreased to less than that of V5+. The activity of VO1.5 was greater than those of the other vanadium oxides, limiting the effect of the slag basicity. Consequently, the valence state of vanadium oxide was affected by the slag basicity at a low oxygen partial pressure by acting as a network modifier. In contrast, at a higher oxygen partial pressure, the activity of vanadium oxide increased further but was not affected by the slag basicity because of its contribution to the network structure formation. The present findings can be applied to optimize the slag composition in steel refining or vanadium pentoxide production processes to increase the yield rate of vanadium. [ABSTRACT FROM AUTHOR]

In the current study, laboratory experiments of the slag‐steel reaction are performed to investigate the effect of CaF2 contents in the refining slag on the inclusion absorption of the bearing steel. The increase of the CaO/Al2O3 ratio effectively enhances the absorption of inclusions by slag. The increase of the CaO/Al2O3 ratio enhances the driving force of the inclusion dissolution and lowers the slag viscosity. It is noted that the excessive CaO/Al2O3 ratio led to the formation of solid phases in the slag, lowering the absorption effect of slag. The appropriate addition of CaF2 in the slag is helpful to remove inclusions while aggravating the corrosion of MgO crucibles. The addition of CaF2 mainly reduces the viscosity and melting temperature of slag. The inclusion removal factor is proposed to effectively evaluate the inclusion removal rate in steel during slag steel reaction. As a result, the most recommended composition of slags is 7% CaF2; the CaO/Al2O3 ratio is 2.0. [ABSTRACT FROM AUTHOR]

Introduction: The production of fluxes for hardfacing by submerged arc welding is based on the consumption of natural minerals. However, there are slags that contain the oxide systems required for a flux. Hardfacing makes it possible to reincorporate worn parts into service. Objective: To evaluate, by means of the Circular Economy approach, the obtaining of fluxes from slags for hardfacing by submerged arc welding. Materials and Methods: A conceptual scheme is proposed, with a Circular Economy approach, to obtain fluxes for hardfacing, using slag and conceiving hardfacing for the restitution to service of worn parts or to manufacture parts with greater durability. Two variants are proposed: The production of ferroalloys, using slags as matrix for a flux, and the obtaining of fluxes, using slags discarded from other productions. Results and Discussion: Different cases are addressed: 1. Obtaining ferrochromium-manganese, conceiving the use of slags as a matrix of a hardfacing flux; 2. Obtaining a hardfacing flux, using slags from submerged arc welding; 3. Obtaining a hardfacing flux, using slag from steel production. The fluxes obtained make hardfacing possible, for the rehabilitation of worn parts or for the manufacture of more wear-resistant parts. Conclusions: The conceptual scheme is validated, by a Circular Economy approach, in obtaining fluxes for hardfacing with the use of slag, making possible the restoration to service of worn parts or to manufacture new, higher-quality parts. [ABSTRACT FROM AUTHOR]

The aim of our research was to indicate the suitability of metallurgical slags (two blast furnace slags and one steel furnace slag) as the components of Cu-free friction materials. The base mixture consisted of nine components including phenolic resin, graphite, tin sulphide, steel and aramid fibers, iron powder, a mixture of barite with calcite, and vermiculite. To this base mixture, the slags with a particle size below 0.1 mm were added individually in the amount of 20 wt.%. A base friction mixture with alumina in the amount of 20 wt.% represented the reference. Samples for the friction-wear tests were produced in the form of pins by hot press molding. The prepared pins were tested using a pin-on-disc tester in a drag mode at the pressure of 1 MPa and a constant sliding speed of 1.51 m/s for 90 min. The samples with slags exhibited slightly lower values of steady-state friction coefficient compared to the reference composite with alumina, and at the same time produced lower wear particle emissions. The particle concentration was reduced for the samples with slowly cooled blast furnace and steel furnace slag. The results obtained indicated steel furnace slag as a promising component of Cu-free friction composites. [ABSTRACT FROM AUTHOR]

The effect of basicity (CaO/SiO2 mass ratio) and FetO on the viscous behavior of CaO–SiO2–FeO–Al2O3–MgO–MnO slag was investigated via stepped-temperature viscometry (1873–1473 K) to predict the thermophysical properties of high-FetO-bearing molten slag. The basicity and FetO contents were varied to determine the constitutional effect of the slags on the physical properties and ionic structure. At low FetO contents (below 15 wt%), the viscosity of high-FetO-bearing slags exhibited a strong dependence on basicity. However, at high FetO contents (above 15 wt%), the viscosity decreased as the FetO content increased, indicating a strong FetO dependency. This behavior was attributed to the change in activation energy as the dominant polymeric structural unit (T–O–T; T = Si, Al, and Fe) varied depending on the equilibrated primary phase. In addition, to understand the change in the dominant polymeric structural unit depending on the FetO content, the relationship between the polymeric structural units and thermophysical properties of high-FetO-bearing slags was studied by analyzing the Fe3+/Fe2+ and nonbridging oxygen fractions of the slag melts.

Herein, a diffusion model for the dissolution of oxide particles in multicomponent slag systems is developed. It is assumed in this model that a sharp‐interface separates the solid particle from the liquid slag. Minimization of the Gibbs energy provides the conditions at the interface. The differential equations for multicomponent diffusion in the liquid slag are solved numerically via a finite‐difference scheme. It is indicated via parameter studies that the diffusion controlled dissolution kinetics may result in strongly different dissolution profiles depending on the initial conditions. It is demonstrated that the rate‐controlling dissipative process is the diffusion of components for cases where earlier investigations claimed that a coupled diffusion‐reaction process is in charge of the dissolution kinetics. Eventually, the numerical results are compared to data obtained from high‐temperature laser scanning confocal microscopy (HT‐LSCM) experiments. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize historical slags which originated during silver production from the Jihlava ore district, Czech Republic. The area was among the head producers of silver within the Lands of the Czech Crown in 13th–14th centuries. The mined ores had complex composition, being formed mostly by pyrite, sphalerite, galena, chalcopyrite, and accessory silver-rich minerals such as silver-bearing tetrahedrite (freibergite) or pyrargyrite, with gangue represented by quartz and Mn-rich carbonates or baryte. Large volumes of slags with contrasting composition were generated during the Pb-Ag production. Altogether, two main types of slags were identified in the district. The first type is characterized by high BaO contents (up to 34.5 wt.%) and dominancy of glass, minor quartz, and accessory amounts of Ba-rich feldspar (up to 93 mol.% of Cls), metal-rich inclusions, Ba-Pb sulphates and only rare pyroxene, wollastonite and melilite. The composition of the second group belongs to fayalitic slags containing glass, Fe-rich olivine, accessory pyroxene, feldspar, quartz, and inclusions of various metallic phases. Fluxes were derived from gangue (quartz, carbonates, baryte) or local host rocks for both types of slag. The calculated viscosity indexes reflect (with minor exceptions) medium-to-high effectivity of metal separation. Smelting temperatures were estimated from a series of ternary plots; however, more reliable estimates for both types of slags were obtained only from experimental determination of melting temperature and calculations using bulk/glass compositions (~1100–1200 °C). [ABSTRACT FROM AUTHOR]

This study presents the first complete reconstruction of gold metallurgy in Złoty Stok, Poland. The key parameters of the process (i.e., temperature of smelting and solidification, melt viscosity, oxygen fugacity) are calculated using the remnants of the process: metallurgical slags. The slags consist of silicate phases (i.e., olivine, pyroxene), sulfides and arsenides (i.e., pyrrhotite, Fe2As), as well as glass. These slags are chemically dominated by SiO2 (< 56.60 wt%), MgO (< 18.36 wt%), FeO (< 15.36 wt%), and CaO (< 15.19 wt%). The obtained results indicate that the temperature during the metallurgical process was at least 1300–1350°C, and crystallization of the slags took place until they cooled to < 1200°C. The morphology of olivine crystals in the slags indicates large differences in their cooling rate, from 5 to 300°C/h. Strongly reducing conditions during the metallurgical process (−10.5 to −11.5 log fO2) was confirmed. Low melt viscosity (logƞ = 0.26 – 0.90 Pa s) facilitated the separation of the sulfide melt rich in gold from the silicate melt being the slag precursor. The obtained results allowed existing descriptions of the smelting process in Złoty Stok to be corrected. [ABSTRACT FROM AUTHOR]

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• We have just discovered solid solutions of Na-Ca-silicates, which have previously assumed to be stoichiometric compounds. • Five new invariant points were suggested based on the data obtained. • Novel liquidus data at Na 2 CaSiO 4 (ss), Na 2 Ca 2 Si 2 O 7 (ss), and Na 2 Ca 6 Si 4 O 15 saturation conditions are reported. • The impact of the solid solutions on the ternary diagram was investigated together with the primary phase fields of SiO 2 , Na 2 Ca 3 Si 6 O 16 , combeite, Na 4 CaSi 3 O 9 (ss), CaSiO 3 , Na 2 CaSiO 4 (ss), Na 2 Ca 2 Si 2 O 7 (ss), Na 2 Ca 6 Si 4 O 15 , Ca3Si 2 O 7 , and Ca 2 SiO 4. • The ternary diagram of Na 2 O-CaO-SiO 2 system including their Alkemade lines has been redrawn. Although phase relations in the Na 2 O-CaO-SiO 2 system are vital to melting and thermal treatments in glass and glass-ceramics industries, the available data for thermodynamic modeling are mostly based on reports published in 1920s and 1950s. The present investigation verifies the formation of solid solutions of Na 2 CaSiO 4 and Na 2 Ca 2 Si 2 O 7 which have previously assumed to be stoichiometric compounds. The impact of these solid solutions on the features of the phase diagram were investigated using the equilibration-quenching-EDS/EPMA technique. The data were reported as liquidus projections and in isothermal sections within the temperature range of 1000 and 1400 °C. Ten primary phase fields were identified, namely SiO 2 , Na 2 Ca 3 Si 6 O 16 , combeite, Na 4 CaSi 3 O 9 ss, CaSiO 3 , Na 2 CaSiO 4 ss, Na 2 Ca 2 Si 2 O 7 ss, Na 2 Ca 6 Si 4 O 15 , Ca 3 Si 2 O 7 and Ca 2 SiO 4. In addition, some novel liquidus data and invariants points were examined in more detail. The fundamental data obtained can be employed for the thermodynamic reassessment of the Na 2 O-CaO-SiO 2 system. The present study also discusses the findings and their impact on melting and annealing processes during the manufacture of glass and glass-ceramics. [ABSTRACT FROM AUTHOR]