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•Biomass upgrading processes to produce fuels for iron and steelmaking are reviewed.•Insights and recommendations for biomass-based reducing agent research are suggested.•Process ...integration opportunities to increase economics and efficiency are proposed.•Biomass use in steelmaking is compared to other low-CO2 steel production technologies.
This paper provides a fundamental and critical review of biomass application as a reducing agent and fuel in integrated steelmaking. The basis for the review is derived from the current process and product quality requirements that also biomass-derived fuels should fulfill. The availability and characteristics of different sources of biomass are discussed and suitable pretreatment technologies for their upgrading are evaluated. The existing literature concerning biomass application in bio-coke making, blast furnace injection, iron ore sintering and production of carbon composite agglomerates is reviewed and research gaps filled by providing insights and recommendations to the unresolved challenges. Several possibilities to integrate the production of biomass-based reducing agents with existing industrial infrastructures to lower the cost and increase the total efficiency are given. A comparison of technical challenges and CO2 emission reduction potential between biomass-based steelmaking and other emerging technologies to produce low-CO2 steel is made.
Iron and steel plants producing steel via the blast furnace-basic oxygen furnace (BF-BOF) route constitute among the largest single point CO2 emitters within the European Union (EU). As the iron ore ...reduction process in the blast furnace is fully dependent on carbon mainly supplied by coal and coke, bioenergy is the only renewable that presents a possibility for their partial substitution. Using the BeWhere model, this work optimised the mobilization and use of biomass resources within the EU in order to identify the opportunities that bioenergy can bring to the 30 operating BF-BOF plants.
The results demonstrate competition for the available biomass resources within existing industries and economically unappealing prices of the bio-based fuels. A carbon dioxide price of 60 € t−1 is required to substitute 20% of the CO2 emissions from the fossil fuels use, while a price of 140 € t−1 is needed to reach the maximum potential of 42%. The possibility to use organic wastes to produce hydrochar would not enhance the maximum emission reduction potential, but it would broaden the available feedstock during the low levels of substitution.
The scope for bioenergy integration is different for each plant and so consideration of its deployment should be treated individually. Therefore, the EU-ETS (Emission Trading System) may not be the best policy tool for bioenergy as an emission reduction strategy for the iron and steel industry, as it does not differentiate between the opportunities across the different steel plants and creates additional costs for the already struggling European steel industry.
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•Full biomass demand by iron and steel plants can be met in the EU.•Use of bio-products in steel plants is viable only at a high CO2 price.•Hydrothermal carbonisation of waste could help initial fossil fuel substitution.•Maximum CO2 emission reduction possible is 91 Mt per year (42%).•Imposing required CO2 price would significantly impact steel production costs.
PM2.5 have been related to various adverse health effects, mainly due to their ability to penetrate deeply and to convey harmful chemical components, such as metals inside the body. In this work, ...PM2.5 were sampled at Saint-Omer, a medium-sized city located in northern France, in March–April 2011 and analyzed for their total carbon, water-soluble ions, major and trace elements. More specifically, the origin of 15 selected elements was examined using different tools including enrichment factors, conditional bivariate probability function (CBPF) representations, diagnostic ratios and receptor modelling. The results indicated that PM2.5 metal composition is affected by both emissions of a local glassmaking factory and an integrated steelworks located at a distance of 35 km from the sampling site. For the first time, diagnostic ratios were proposed for the glassmaking activity. Therefore, metals in PM2.5 could be attributed to the following anthropogenic sources: (i) local glassmaking industry for Sn, As, Cu and Cr, (ii) distant integrated steelworks for Ag, Fe, Cd, Mn, Rb and Pb, (iii) heavy fuel oil combustion for Ni, V and Co and (iv) non-exhaust traffic for Zn, Pb, Mn, Sb, and Cu. The impact of such sources on metal concentrations in PM2.5 was assessed using a constrained receptor model. Despite their low participation to PM2.5 concentration (2.7%), the latter sources were found as the main contributors (80%) to the overall concentration levels of the 15 selected elements in PM2.5.
•Influence of steelworks emissions on metal concentrations in PM2.5 35 km away.•4 sources explained 2.7% of the PM2.5 but also 80% of the metal concentration.•Diagnostic ratios for the glassmaking activity were determined for the first time.•Influence of glassmaking factory on Sn, As, Cr and Cu atmospheric concentrations.
Phosphorus is an indispensable nutrient element in agriculture and its reserves are limited. To secure a sustainable supply of phosphorus, phosphate recovery from dephosphorization slag generated in ...steelmaking was considered a promising solution. In this study, acid leaching was adopted to separate the P-concentrating solid solution from dephosphorization slag. Selective leaching of P from slags with various basicity in the hydrochloric acid solution and chemical precipitation of phosphate ions in the leachate were investigated. Increasing slag basicity facilitated the enrichment of P2O5. Large amounts of Ca, Si, and P were leached from slag, whereas the leaching of Fe was negligible. The leaching efficiency of P increased with slag basicity. At pH 3, the leaching efficiency of P from slag with high basicity reached 96.8% while that of Fe was nearly zero. Almost all the P-concentrating solid solution was dissolved without significant dissolution of the Fe-bearing matrix phase and magnesioferrite. After leaching, the residue containing 57.8% Fe2O3 can be reutilized as a metallurgical feedstock. Through chemical precipitation, a precipitate containing 35.1% P2O5 was recovered from the leachate, which can be used as a phosphate fertilizer. The total recovery efficiency of P from dephosphorization slag in this process reached 95.8%.
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•The leaching efficiency of P reached 96.8% without Fe dissolution.•The Fe2O3-rich residue can be reused as a metallurgical feedstock.•A precipitate containing 35.1% P2O5 was recovered from the leachate.•An efficient method for phosphate recovery from slag was provided.
This paper analyses some possible means by which renewable power could be integrated into the steel manufacturing process, with techniques such as blast furnace gas recirculation (BF-GR), furnaces ...that utilize carbon capture, a higher share of electrical arc furnaces (EAFs) and the use of direct reduced iron with hydrogen as reduction agent (H-DR). It is demonstrated that these processes could lead to less dependence on—and ultimately complete independence from—coal. This opens the possibility of providing the steel industry with power and heat by coupling to renewable power generation (sector coupling). In this context, it is shown using the example of Germany that with these technologies, reductions of 47–95% of CO2 emissions against 1990 levels and 27–95% of primary energy demand against 2008 can be achieved through the integration of 12–274 TWh of renewable electrical power into the steel industry. Thereby, a substantial contribution to reducing CO2 emissions and fuel demand could be made (although it would fall short of realizing the German government’s target of a 50% reduction in power consumption by 2050).
•Carbonation pathways and carbon capture mechanisms of steel-making slags were summarized.•Effects of carbonation pathways on the carbonation capacity of steel-making slags were ...evaluated.•Carbonation products obtained from different carbonation pathways were analyzed and compared.•Scale-up applications and main challenges of steel-making slags carbonation technology are summarized and prospected.
With the rapid development of economy and industrialization, the consumption of natural resources has risen sharply. A large number of greenhouse gases and industrial solid waste emissions have exacerbated global warming, resulting in a series of environmental degradation problems. Using natural minerals or industrial solid waste for carbon dioxide capture and utilization (CCU) is considered to be a feasible and promising technology. From the perspective of circular economy, steel-making slag as carbon dioxide storage material has great economic and environmental value. This paper summarized the main carbonation pathways and carbon capture mechanisms of industrial solid wastes. The carbonation processes of the most representative solid waste of steel-making slags were compared, the effects of different carbonation pathways on the carbonation capacity of steel-making slags were evaluated, and the characteristics of carbonation products obtained from different carbonation pathways were also compared. In addition, the industrial application status of carbon dioxide carbonation technology of steel-making slags was analyzed, and the main challenges it faces were summarized and prospected. We hope that this review can attract extensive attention of scholars and promote the further development of carbon dioxide storage technology by mineralization of steel-making slag.
Magnesium oxide (MgO) contained in steelmaking slags in its liberated form, referred to as free MgO, expands when hydrated. The expansion of free MgO sometimes causes the deterioration of steelmaking ...slags used as construction materials for roads. Therefore, a method that determines the free MgO content in steelmaking slags is required. Solvent extraction is a promising preparation method for determining free MgO in steelmaking slags. Herein, organic solvents were explored for their extraction capabilities, and MgO was successfully extracted with 2,2,2-trichloroethanol (TCE) at 140°C over 3 h. TCE could not be used to extract any other magnesium compounds in blast furnace slags or merwinite, which contain no free MgO, indicating that free MgO was selectively extracted with TCE. The MgO content determined by TCE extraction and atomic absorption spectrometry was found to be reasonably consistent with that determined by other methods, which implies that this method is suitable for measuring the MgO content in steelmaking slags. The mechanism for the extraction of MgO by TCE was also investigated, and it was found that TCE extraction occurred via an acid-base reaction and an oligomerization crosslinking reaction.
Steelmaking slag came to be used in a marine environment and safety issue of slag material is a matter of concern. We are trying to provide the safety information of the slag material. Experimental ...facility with mesocosm aquarium tank, which integrated tidal flat area and shallow area, was constructed in order to evaluate the environmental impact. The facility consists of two aquarium tanks, one is the experimental unit using slag materials as dredged soil improver, called CaO-improver, and another is the control unit not using slag materials. Long-term operation over the five years from 2012 to 2017 was carried out to evaluate the long-term safety of slag materials. We observed not only the changes of water quality but also the acute and chronic toxicity assessment using three kinds of aquatic marine organisms such as bioluminescent bacteria, micro algae and copepod for seawater in the aquarium tanks. As a result of the long-term experiment, stabilization of bottom sediment by CaO-improver could be confirmed, but on the other hand, influence of alkali elution from slag was estimated. Furthermore, as a result of three bioassays, it was judged that there was no effect of acute toxicity and chronic toxicity on organisms caused by slag material within the range examined.
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•BOF slag and phosphate tailings were synergistically treated to recover P.•P2O5 was concentrated in a specific mineral phase in the synthetic slag.•Selective leaching was applied for ...separation of the P-rich phase.•Undissolved synthetic slag can be reutilized as a flux in steel plants.•The precipitate extracted from the leachate can be used as a P-Si fertilizer.
To efficiently recover phosphorus from industrial solid wastes, the collaborative processing of P-bearing steelmaking slag and phosphate tailings was proposed. Steelmaking slag and phosphate tailings were remelted to make P enrich in a specific mineral phase and then selective leaching was adopted to separate the P-concentrating mineral phase. The P-concentrating leachate can be used to recover calcium phosphate by chemical precipitation. It shows that the P was mainly concentrated in the dicalcium silicate after remelting of steelmaking slag and phosphate tailings and it could be selectively leached. When the mass ratio of the original BOF slag to phosphate tailings was 7:3, the mixed slag with basicity of 2.3 was obtained. The dissolution efficiency of P from this mixed slag reached 89.2% whereas Fe was barely leached at pH 1. The residue containing 68.6% FetO and 15.6% MgO can be reused in the metallurgical process. When the pH of leachate was adjusted to 7, more than 89.3% of phosphate ions precipitated in the form of calcium phosphate, and the obtained precipitate containing 28.8% CaO, 19.8% P2O5, and 47.2% SiO2, could be a potential P-Si fertilizer. The total recovery ratio of P from mixed slag was approximately 80% and other components could be reused in steel plants, achieving the comprehensive utilization of steelmaking slag and phosphate tailings.
High strength low alloy (HSLA) steels with tempered martensite microstructure are widely applied in the offshore industry such as fasteners. The subsea environment conditions are quite favorable for ...severe hydrogen embrittlement (HE). Their good hardenability influences the achievement of excellent mechanical properties. Three different steelmaking routes such as continuous casting (CC), conventional ingot casting (CIC) and electroslag remelting (ESR) were investigated to verify the influence on the AISI 4140 steel microstructure and the HE susceptibility. Electrochemical hydrogen permeation tests were correlated with the microstructure obtained from each route that presented different levels of segregation bands. The CC process was responsible for the appearance of a high density of non-metallic inclusions (NMIs) like manganese sulfide (MnS) and impurities in segregation regions that increased the HE degree. The ESR route presented the best mechanical behavior due to the lowest reduction in ductility for hydrogenated uniaxial tensile test conditions and, consequently, the highest resistance regarding the HE.
•Hydrogen embrittlement in high strength low alloy produced from steelmaking routes.•Hydrogen diffusivity and solubility in the high strength low alloy AISI 4140.•Effects of segregation bands on the hydrogen embrittlement in the high strength low alloy AISI 4140.
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