Production Lag Research Articles

Exploration of fungal resistivity and mechanical performance of Zn-phases-doped geopolymers: ZnO and Zn/Al-LDH nanoparticles

Generation of green geopolymer pastes that are based on a 1:1 slag/fly ash ratio (Geo) is the main objective of this study owing to the limited production of cementitious slag in Egypt. Different doses of ZnO and Zn-Al-CO3 layered double hydroxide (LDH) were individually incorporated in geopolymer pastes to attain our aim and are coded Geo, Geo-0.5 %ZnO, Geo-1 %ZnO, Geo-0.5 %LDH, and Geo-1 %LDH. Setting times of fresh pastes and compressive strength of hardened pastes up to 28-days of conventional alkali-activation have been measured. Setting times of fresh pastes and compressive strength of hardened pastes up to 28-days of conventional alkali-activation have been measured. The results confirmed that adding ZnO and LDH NPs to the neat geopolymeric paste (Geo) significantly accelerated the setting process within 7–23 mins, especially for samples Geo-1 %ZnO and Geo-1 %LDH with 7/17 and 8.4/17.5 min., respectively. On the other hand, mechanical results indicated that pastes containing zinc oxide had poor compressive strength, especially in the early stages while 0.5 % LDH nanoparticles had a positive role as the strength values reached 8.9, 40, 60 MPa at 1, 7, and 28 days of curing, respectively. This behaviour is attributed to creating different types of zinc/silicon-containing phases like zinc-alumino-silicate-hydrates (Z-A-S-H, Zn6Al12Si12O48.29H2O), zinc-silicate-hydroxide-hydrate (Z-S-H, Zn4Si2O7(OH)2·H2O) and calcium-zinc-silicate (CaZnSi2O6) which detected by XRD. Moreover, TGA and SEM techniques affirmed the catalytic performance of LDH nanoparticles inside the geopolymeric structure as extra quantities of CSH, CASH, and C3AH6 have been generated. Anti-fungal activity test for some selected geopolymeric pastes was conducted via agar diffusion test (ASTMD4300–1). Geo-0.5 % ZnO and Geo-0.5 %LDH samples possessed the highest recorded inhibition zones against Aspergillus Niger and Mucor Circinelloid -AUMMC 11656, especially against Penicillium Glabrum-OP69417 with 51±1, and 67±2, respectively.

Applications of H2-Enriched syngas and slag products from plastic wastes via novel plasma dual-stage-arc pyrolysis

Sustainable plastic waste management in the prevailing ‘new-normal’ post-pandemic scenario calls for calorific waste plastic up-cycling into high-end product recovery pathways. The present work employed a novel dual-stage arc plasma pyrolysis reactor to recover syngas and slag products from mixed plastics and Low-Density Polyethylene and Polyethylene Terephthalate (LDPE-PET) plastic waste feeds. Syngas product yield decreased while the solid slag yield increased with rising arc current, attaining 75% and 25% for mixed plastic waste feed and 59% and 41% for LDPE-PET wastes, respectively, at 200A arc current. The resultant syngas composition showed 83% and 77% H2 while 1.7% and 2.7% CO for mixed plastic waste-feed and LDPE-PET wastes, respectively, with no significant presence of CO2. Slag characterization studies revealed the presence of scattered pores on the slag surface, graphitic nanostructures due to scraped carbon depositions from electrode tips and the absence of aromatic groups due to complete conversion. High carbon content was observed in the slag due to the dissociation of lighter hydrocarbon and carbon dioxide on dual-arc exposure in two stages, underscoring the higher efficiency. For holistic integrated circular onsite ‘plastic waste-to-resource’ recovery-cum-application, electricity was generated from the resultant syngas and the slag was used for the manufacture of tiles in the community platform. Techno-economic evaluation of an up-scaled plasma pyrolysis facility shows the power recovery of 3.5 kWh/kg of waste plastic, with a net annual profit of $2800 and a payback period of 1.7 years. The findings of the present work suggest that the proposed integrated dual-arc plasma pyrolysis based plastic waste-to-resource recovery in circular-economy model has a viable outcome.

Production and recycling of blast furnace slag: A life cycle assessment approach in India

AbstractThis article investigated the cradle‐to‐gate environmental impact of granulated blast furnace slag (GBFS) produced in the steel industry and replacement of blast furnace (BF) slag (50%) in place of clinker in Portland slag cement using GaBi software (Indian extension database). In case of GBFS production, maximum burden on the environment is due to BF slag production and the amount of electricity consumed (161 MJ/ton) during the granulation process. The influence of electricity sources on GBFS production was studied via scenario analysis. For investigation, solar and thermal electricity mixes were considered in 50:50 and 75:25 ratios. For the 75:25 ratios, the abiotic depletion potential (fossil), acidification, eutrophication, global warming, and human toxicity potential show a decreasing trend of approximately 45%, 49%, 48%, 46%, and 41%, respectively. The scenario analysis of BF slag transportation (from 100 to 750 km) demonstrates a negative impact due to fuel. The results quantitatively confirm that the addition of GBFS can lower the overall impact for construction and steel industries.

Enriched Linz-Donawitz (LD) slag application for improving grain yield and quality of wheat grown under nutritionally poor degraded soil

Aim: To evaluate the impact of enriched steel slag on the physico-chemical characteristics of soil and yield attributes of wheat under poor quality degraded soil. Methodology: Steel slag was biologically and organically amended with natural sources of phosphorus (P), sulfur (S), potassium (K) and nitrogen (N) and characterized for its nutrient content along with biological activity. The impact of resultant products was assessed on soil quality and yield component traits of wheat for two consecutive years (2021-2022 and 2022-23). Results: Application of slag based products significantly (p<0.05) improved the plant height, biological yield, grain yield and ear bearing tillers (EBT) of wheat even with 80% of recommended fertilizer dose (NPK). Further, in comparison to control, a moderation of soil pH (8.6 to 8.8), EC (0.18 to 0.20 dS m-1), OC (0.22 to 0.24 %) and essential mineral macronutrients viz., N (126 to 130 kg N ha-1), P (8.0 to 13.0 kg ha-1), K (100 to 125 kg ha-1) were observed with the application of amended steel slag products. No significant change with respect to existing heavy metal concentration viz., Co, Ni, Cd and Pb in soil was observed when supplemented with amended slag products. Interpretation: Steel slag can be transformed favorably for on-farm application to improve wheat yield besides serving as an environmentally sustainable alternate of soil conditioner for the management of degraded soil. Key words: Degraded soil, Heavy metals, Steel slag, Waste management, Wheat

Effect of sintering behavior and phase evolution on glass-ceramics entirely derived from ferrochrome slag and fluorite tailings

The recycling of solid waste is widely regarded as the one of the most crucial issues of sustainability. This is particularly evident in the industrial sector, where the production of slags is huge and their handling presents a significant challenge. In this study, solid wastes from the industrial sector, namely ferrochrome slag (Fs) and fluorite tailings (Ft), were employed for the preparation of glass-ceramics by the sintering method. Three glasses were prepared by using the melt-quenching method, with a weight ratio of 60∼70 % Fs and 40∼30 % Ft (designated S30, S35, and S40, where the higher number indicates a greater Fs content). The sintering and crystallization behaviors of these glasses were characterized by hot-stage microscopy (HSM) and differential thermal analysis (DTA). It was observed that S40 glass exhibited a weak sintering capacity in comparison to that of S30 and S35 glass, which can be attributed to the robust crystallization propensity of S40 glass. The coarser glass frits were subjected to sintering experiments at varying temperatures, which demonstrates that the predominant crystalline phase is augite and that Cr2O3 remains present in all sintered samples. Besides, a transition of the Cr2O3 crystal into uvarovite was observed in S40 glass sintered at 1050 °C. The sintering time controlling experiment demonstrated that both wollastonite and the Ca-rich flow formed during sintering are vital for the formation of uvarovite. The formation of uvarovite can enhance the hardness of GCs. All GCs samples sintered at 1050 °C and 1120 °C exhibit comparable mechanical performance.

Intensified extraction of vanadium from vanadium-bearing titanomagnetite (VTM) concentrate via one-stage leaching and solvent extraction using acidic organophosphorus extractant

Vanadium-bearing titanomagnetite (VTM) is a crucial source for vanadium production. Conventional methods for recovering vanadium from VTM involving combined pyro- and hydrometallurgy (production of vanadium-rich slag, followed by leaching) or direct leaching encounter significant challenges, such as vanadium losses and complexities in metal separation stage. This study proposes an innovative approach for vanadium extraction from VTM through one-stage leaching and solvent extraction (SX), utilizing an acidic organophosphorus extractant, di(2-ethylhexyl)phosphoric acid/D2EHPA, as the lixiviant. Initial assessment demonstrated the viability of D2EHPA for treating vanadium oxide (V2O5) and iron oxides (only Fe2+-containing oxides like Fe3O4 and FeO). Notably, the addition of a small amount of water had a significant impact on iron extraction. The study investigated the effects of parameters, including the amount of added water, stirring speed, D2EHPA concentration, temperature, time, and pulp density on the vanadium and iron extraction from VTM. The optimal conditions were applied to treat roasted/oxidized VTM. The findings were corroborated through analysis of the resultant loaded D2EHPA using appropriate techniques such as FTIR and UV–Vis spectroscopy. The practicability of the proposed method for treating VTM concentrate on a larger scale was demonstrated by conducting up-scaled tests. Additionally, the separation of vanadium from iron the loaded D2EHPA was explored using selective stripping with H2SO4 solution. The recyclability of D2EHPA, a critical factor for sustainability, was investigated through five cycles of extraction-stripping.

The performance and charge behaviour in melter/smelter for the production of hot metal in hydrogen DRI-based steelmaking

Direct reduced iron (DRI)-based steelmaking requires high-grade iron ore (Fe > 65 wt-%). However, a swift decline in ore grade has forced steelmakers to use lower-grade ores for DRI making, creating challenges in subsequent processes dealing with high gangue content for steelmaking. Hence, an intermediate melting/smelting furnace has been proposed to treat high gangue content from the DRI before transferring hot metal into an electric arc furnace (EAF)/basic oxygen furnace (BOF) for steelmaking. This study investigates and models the performance and charge behaviour in a melter/smelter with respect to the gangue content, DRI carbon content and temperature. The results showed that the specific energy consumption (SEC) and off-gas production increase with increasing temperature, carbon in DRI and gangue content. At 90 wt-% metallisation ratio (MR) using the lowest-grade ore (gangue 16 wt-%), the SEC at 1300 °C was calculated to be 706 kWh/tHM compared to 850 kWh/tHM at 1600 °C using 3.5 wt-% carbon. The MR is predicted to profoundly impact the SEC, as the increasing MR decreases the SEC markedly. At 90 wt-% MR, the SEC using the lowest-grade ore was 805 kWh/tHM, decreasing to 684 kWh/tHM using 100 wt-%MR. Increasing MR, carbon in DRI and temperature decreases slag production consistently while increasing with the increasing gangue. Using hot DRI onsite is predicted to significantly reduce the SEC compared to cold DRI. Overall, the energy demand from cold DRI is predicted to be 120 kWh/tHM higher than hot DRI. Increasing the scrap-to-DRI ratio is predicted to decrease the energy demand, that is, every 1.0 wt-% increase in scrap decreases the SEC by 2.5 kWh/tHM.

Advances in in-situ resources utilization for extraterrestrial construction

To establish foundational support for forthcoming deep space exploration and settlement endeavors, the significance of extraterrestrial construction has become paramount. Recent developments underscore a growing acknowledgment of the imperative role played by in situ resource utilization, attributed to its potential for cost efficiency and facilitation of sustainable progress. This paper compiles and categorizes the advancements in this domain, focusing on three distinctive categories of in situ resources: regolith, water–ice, and energy resources. A review of their distribution, acquisition, and utilization procedures is presented. Subsequently, an intricate examination ensues, elucidating the applicability of each resource within the context of extraterrestrial construction, in conjunction with five prevalent technologies and the latest architectural constructs. Drawing insights from the research, the existing limitations are identified, particularly pertaining to the comprehensive, deep processing, and sustainable utilization of resources. Consequently, a proposition is put forth to address these challenges. Prospective investigations are recommended, focusing on the mining of water–ice, the metallurgy and production of regolith and slag, and the integrated construction in the pursuit of extraterrestrial construction and operational endeavors.

Innovative strategy for comprehensive utilization of vanadium slag: Maximizing valuable metals recovery and minimizing hazardous waste generation

Compared to traditional methods, which faced challenges such as enormous toxic waste and low efficiency, self-pressure acid leaching (SPAL) presented a promising solution for the cleaner production of vanadium slag (VS). Under controlled conditions, the structure of vanadium slag (VS) could be disrupted by SPAL. Meticulous optimization of the SPAL process parameters had resulted in remarkable recovery efficiency: 97.72 % for vanadium, 86.09 % for chromium, 90.27 % for manganese, and 94.73 % for iron at 433 K. Mechanism studies revealed that titanium and silicon followed a "dissolution before precipitation" mechanism and ultimately enriched in the non-toxic residue. Importantly, due to the absence of extra oxidants, all metal ions in the leaching solution remained in a low valence state, effectively eliminating the generation of toxic V(V) and Cr(VI). This approach holds significant promise for the efficient and environmentally friendly recovery of valuable metals from VS, while minimizing the production of toxic waste.

Impact of basic oxygen furnace slag on the hydration microstructure, mechanical properties, and carbon emissions of supersulfated cement

Supersulfated cement (SSC) is recognized as a cementitious material with low CO2 emissions, consisting predominantly of ground granulated blast-furnace slag (GGBS) and a minor activator content. The production of GGBS production constitutes the primary source of CO2 emissions in SSC. In contrast, carbon emissions from the production of basic oxygen furnace slag (BOFS) are lower, and BOFS inherently exhibits substantial carbonization potential. Therefore, in this study, BOFS is employed as a replacement for GGBS in formulating an innovative low-emissions binder denoted as BOFS-modified supersulfated cement (BMSC). This study investigates the influence patterns of BOFS substitution for GGBS on the strength properties of BMSC. Furthermore, a series of experiments involving QXRD, TGA, SEM, and MIP were conducted to systematically investigate the mechanistic impact of BOFS on the hydration microstructure of BMSC. The findings reveal that substituting 10 % of GGBS with BOFS contributes to an enhancement in both flexural and compressive strength of specimens at 7 and 28 days. BOFS exerts a positive influence on the formation of ettringite in BMSC. The C2S and C4AF within BOFS also demonstrate distinct hydration activity. Additionally, BOFS can reduce large pores in the early hydration paste and contribute to narrowing the average pore size. Moreover, the evaluation of the Global Warming Potential (GWP) demonstrates that the replacement of slag with BOFS can lead to a further reduction of up to 30 % in the carbon emissions of SSC.

Experimental Investigation of Sustainable Concrete Production using Blast Furnace as A Cement Substitute- A art of Review

The pursuit of sustainable construction practices has led to a growing interest in alternative materials that can reduce the environmental impact of traditional concrete production. This experimental study focuses on the utilization of blast furnace slag as a substitute for cement in concrete, aiming to assess its mechanical properties, environmental impact, and overall sustainability. The primary objectives of this research are threefold. Firstly, the study seeks to evaluate the mechanical properties of concrete by varying the content of blast furnace slag in the mix, with a specific emphasis on strength, durability, and structural performance. This involves conducting a comprehensive analysis of the concrete's compressive strength, flexural strength, and other relevant mechanical characteristics. Secondly, a life cycle assessment (LCA) will be employed to analyze the environmental impact of the concrete mixtures. This assessment will compare carbon dioxide (CO2) emissions, energy consumption, and overall sustainability of the concrete produced with varying percentages of blast furnace slag. The LCA will provide valuable insights into the environmental implications of using slag as a cement substitute, aiding in the identification of eco-friendlier concrete production practices. Lastly, the research aims to assess the environmental impact of blast furnace slag itself when employed as a cement substitute. This involves examining the production, transportation, and incorporation of blast furnace slag into the concrete mix, providing a holistic view of its sustainability across the entire life cycle. The experimental approach involves the meticulous design of concrete mixes with different percentages of cement replaced by blast furnace slag. The varying mix designs will be tested for mechanical properties, and the data obtained will be used to draw correlations between slag content and concrete performance. In summary, this research endeavors to contribute to the body of knowledge surrounding sustainable concrete production by exploring the mechanical, environmental, and sustainability aspects of utilizing blast furnace slag as a cement substitute. The findings of this study are anticipated to provide valuable insights for the construction industry to adopt more environmentally friendly practices while maintaining or enhancing concrete performance.

A finite-element method model for a ferromanganese and silicomanganese pilot furnace

We report on the development of a finite-element method model for a pilot furnace for the production of manganese alloys. The model is a multiphysics model that addresses material flow, electrical conditions, heat transfer, and physical and chemical transformations. It is capable of studying both quasi-steady and transient states in time-dependent simulations. The model includes common charge materials and fluxes and can simulate production of both ferromanganese and silicomanganese alloys with acid and basic slags, as well as changing charge compositions. The model output provides access to the material distribution in the furnace during furnace runs, temperature profiles, current paths, energy balances, and alloy and slag production rates and compositions.

Methacrylic acid in situ modified steel converter slag/natural rubber composites: Resourceful utilization of steelmaking solid wastes

As a by-product of the steelmaking industry, the large-volume production and accumulation of steel converter slag cause environmental issues such as land occupation and dust pollution. Since metal salts of unsaturated carboxylic acid can be used to reinforce rubber, this study explores the innovative application of in-situ modified steel slag, mainly comprising metal oxides, with methacrylic acid (MAA) as a rubber filler partially replacing carbon black. By etching the surface of steel slag particles with MAA, their surface roughness was increased, and the chemical bonding of metal methacrylate salt was introduced to enhance their interaction with the molecular chain of natural rubber (NR). The results showed that using the steel slag filler effectively shortened the vulcanization molding cycle of NR composites. The MAA in-situ modification effectively improved the interaction between steel slag and NR molecular chains. Meanwhile, the physical and mechanical properties, fatigue properties, and dynamic mechanical properties of the experimental group with MAA in-situ modified steel slag (MAA-in-situ-m-SS) were significantly enhanced compared with those of NR composites partially filled with unmodified slag. With the dosage of 7.5 phr or 10 phr, the above properties matched or even exceeded those of NR composites purely filled with carbon black. More importantly, partially replacing carbon black with modified steel slag reduced fossil fuel consumption and greenhouse gas emission from carbon black production. This study pioneered an effective path for the resourceful utilization of steel slag and the green development of the steelmaking and rubber industries.

Production of high-manganese slag by reducing iron and phosphorus in ferromanganese ores with hydrogen

Production of high-manganese slag by reducing iron and phosphorus in ferromanganese ores with hydrogen

Effect of Thermal Activation on the Mineralogical Structure of Magnesium Slag

Magnesium slag's production process is similar to the Portland cement production process. The raw material used is carbonate-containing dolomite, and is calcined in a rotary kiln at 850-900 oC. Afterwards, ferrosilicon and fluorite raw materials are added to the calcined material, they are ground together and turned into pellets, and then they are reduced at a temperature close to the firing temperature of Portland cement clinker (1250-1350 oC) to obtain crown magnesium and magnesium slag. The reduction time of pellet material in reduction furnaces is 12 hours. During this period, almost all of the magnesium minerals in the mixture material are reduced and taken as crown magnesium metal. The remaining material, described as magnesium production slag (reduction furnace waste), consists of Alite (C3S), Belite (C2S), Celite (C3A) and C4AF minerals contained in Portland cement clinker. Some of the minerals contained in Portland cement clinker in the rotary kiln are formed at temperatures below 1400 °C, which is the clinker firing temperature. The only difference other than the firing temperature is that after the Portland cement clinker is fired in the rotary kiln, the clinker is cooled rapidly, increasing the alite (C3S) crystals formed in its structure and preventing the alite minerals from turning back into belite (C2S) minerals. This study produced magnesium slags at different temperatures (1200-1350 oC) by thermal activation method in an industrial environment. The Bogue and XRD methods calculated the mineral phase amounts of the products produced.

Characterisation of the Grain Morphology of Artificial Minerals (EnAMs) in Lithium Slags by Correlating Multi-Dimensional 2D and 3D Methods

Slags from the metallurgical recycling process are an important source of resources classified as critical elements by the EU. One example is lithium from Li-ion battery recycling. In this context, the thermodynamic properties of the recycled component system play a significant role in the formation of the Li-bearing phases in the slag, in this case, LiAlO2. LiAlO2 crystal formation could be engineered and result in varying sizes and occurrences by different metallurgical processing conditions. This study uses pure ingredients to provide a synthetic model material which can be used to generate the valuable phase in the slag, or so-called engineered artificial minerals (EnAMs). The aim is to investigate the crystallisation of LiAlO2 as an EnAM by controlling the cooling conditions of the model slag to optimise the EnAM formed during crystallisation. Characterisation of the EnAMs is an important step before further mechanically processing the material to recover the valuable element Li, the Li-bearing species, respectively. Investigations are conducted using powder X-ray diffraction (XRD), X-ray fluorescence (µXRF), and X-ray Computer Tomography (XCT) on two different artificial lithium slags from MnO-Al2O3-SiO2-CaO systems with different cooling temperature gradients. The result shows the different EnAM morphology along the height of the slag, which is formed under different slag production conditions in a semi-pilot scale experiment of 5 kg. Based on the different EnAM morphologies, three defined qualities of the EnAM are identified: granular, dendritic, and irregular-shape EnAM.

Towards a green climate: Production of slag–red brick waste-based geopolymer mingled with WO3 nanoparticles with bio-mechanical achievements

According to the sustainability concept, this work developed a green geopolymeric composite (Geo) prepared by mingling 50 wt%slag+ 50 wt%brick-waste (BW) as an alternative eco-friendly and low-cost cementitious material. The main target of this study is to fnd a solution to the problem of poor characteristics of binding materials containing high proportions of BW; most previous studies recommended using only 10–20 wt%BW. The compressive-strength results showed that replacing slag with 50 wt% BW reduced the strength from 47 to 24.6 MPa at normal curing conditions for 28-days, referring to the detrimental impact of BW on mechanical performance. In an endeavour to enhance the mechanical performance of this composite, different doses from laboratory-prepared tungsten oxide nanoparticles (0.25, 0.5, 1 wt%WO3-NPs) and hydrothermal curing at various steam-pressure/periods were used. From an economic point of view, hydrothermally treated Geo-paste modified with 0.25 wt%WO3-NPs at 3 bar/4hrs was selected as an ideal composition/curing-conditions; the compressive-strength reached 54.5 MPa exceeding the standard limit of Portland cement (42.5 MPa). This clearly shows the synergistic role of using WO3-NPs and hydrothermal curing to enhance the compressive-strength, which was confirmed using different analysis techniques. XRD, TGA/DTG and SEM/mapping proved that the catalytic performance of WO3-NPs/hydrothermal-curing participates in augmenting binding hydrates, creating a cubic-stable-phase of tricalcium-aluminate-hydrate (C3AH6) and different types of zeolitic-like structure (spherical Zeolite-NaP, rods analcime and stacked-plates cancrinite). To maximize the benefits of employing WO3-NPs in the developed composites, their anti-microbial activity was studied. The measured inhibition zone around specimens containing WO3-NPs proved that these composites have a superior self-cleaning efficiency against Candida albicans, Mucor circinelloides, Salmonella typhi and Staphylococcus aureus due to the WO3-NPs’ photocatalytic activity.

POTENTIAL FOR THE USE OF ASH AND SLAG FROM COAL-FIRED THERMAL POWER PLANTS FOR PRODUCTION OF ALTERNATIVE FUELS (ON THE EXAMPLE OF ASH AND SLAG FROM LADYZHYNSKA THERMAL POWER PLANT)

The combustion of coal to generate electricity at coal-fired power plants results in the production of a sub-product, ash and slag. It is a mixture of non-combustible mineral particles from the fuel and the remains of unburned coal. The growing demand for electricity, especially in developing countries, is leading to an increase in coal ash and slag production, which currently amounts to about 1 billion tons per year. Awareness of the dangers of accumulating such large volumes of industrial waste is stimulating interest in ash and slag utilization technologies by using them to correct industrial landscapes, build roads, and as a cheap aggregate and component of concrete mixtures. However, it seems much more promising to utilize ash and slag through deep processing with separation into separate components: fly ash, unburned carbon, and iron oxide concentrate, which have wide markets and high enough value to make the ash processing process economically attractive. A particular interest is the production of fine carbon concentrate, which is a promising intermediate product for the production of water-coal fuel, a substitute for fuel oil and crude oil in the energy sector. Bibl. 19, Fig. 3, Tab. 4.

Fate of Cl and chlorination mechanism during municipal solid waste incineration fly ash reutilization using thermal treatment: a review.

Safe and sustainable treatment of municipal solid waste incineration fly ash (MSWI FA) is urgently needed worldwide because of its high heavy metals, dioxin, and chlorine (Cl) contents. Thermal treatment is widely considered as a promising method for treating MSWI FA owing to its high toxic content removal efficiency and resource recovery; however, residual Cl is a concurrent critical problem faced during reutilisation of thermal treatment products. This review summarises the innovative thermal treatment methods of MSWI FA, such as those employed in production of cement, lightweight aggregates, glass slag, and metal alloys. The characteristics of Cl in MSWI FA, removal rate, transformation of water-soluble Cl into water-insoluble Cl, and the effect of different influencing factors such as temperature, composition, superheated steam, and mechanical pressure were analysed. The volatilization and decomposition of NaCl, KCl and CaClOH dominates Cl removal; however, the degradation of organic Cl and heavy metal chlorination volatilization process that generate HCl and heavy metal chlorides, respectively, also contributed to Cl removal. To promote the reutilisation of MSWI FA-based products, the leaching behaviour of residual Cl in products obtained by different thermal treatments was investigated.

Ladle Furnace Slag: Synthesis, Properties, and Applications

AbstractLadle slag is a byproduct formed during the ladle refining stage of steel making. It is a dusty material that has been considered industrial waste. Technical advancements towards a sustainable industry led to the development of different applications for ladle slag. Depending on the processing methods during the steel slag production and the weathering of the slag post‐production, the elemental composition of the steel slag largely varies. Owing to this, its characteristics cannot be generalized and specific applications depending on the sources are developed. It is generally used in construction materials, soil rejuvenation, and CO2 capture. This paper reviews the production process, the mineralogical and morphological properties, stabilization techniques, and the applications of ladle furnace (LF) slag. One of the prime focuses of waste remediation and sustainable industry is to find meaningful ways to turn waste into products. In this respect, a comprehensive review of the properties of LF slag and its current application will help provide a framework for the development of future sustainability goals. With increased slag usage, the ladle refining process of steelmaking can be turned into a more carbon‐neutral process.