disadvantages of steel slag

By making research easy to access, and puts the academic needs of the researchers before the business interests of publishers. The reaction products are oxides, which are finally incorporated into the slag. To begin the lab, first all the correct equipment and materials had to be collected. It is normally agreed that the cementitious properties of steelmaking slag increases with its basicity. Informational Resources on slag in concrete, FREQUENTLY ASKED QUESTIONS ON SLAG IN CONCRETE. Surface tension consists in a physical property that depends principally on the surface and not on the bulk. A great part of the steel produced in the world is obtained through electric arc furnace (EAF), the process involves the use of scrap metal and reduces the CO2 emissions. Free calcium and magnesium oxides are not completely consumed in the steel slag, and there is general agreement in the technical literature that the hydration of unslaked lime and magnesia in contact with moisture is largely responsible for the expansive nature of most steel slags. If a carbonaceous material is added after blow, C reacts with FeO and generates CO, Eq. Unable to load your collection due to an error, Unable to load your delegates due to an error. Sometimes when a food product is a little more than others it is because the ingredients that make it are the processed like, Procedure and Observations This requires an additional cooling system to absorb heat from the heat-affected zones. These different slags must be segregated from furnace slag to avoid contamination of the slag aggregate produced. Clipboard, Search History, and several other advanced features are temporarily unavailable. Fax: 1.248.848.3701, ACI Middle East Regional Office Emery, J. J. The https:// ensures that you are connecting to the The primary applications for steel slag in the United States are its use as a granular base or as an aggregate material in construction applications. Tufalike precipitates, resulting from the exposure of steel slag aggregates to both water and the atmosphere, have been reported in the literature. In Figure 1, a comparison of the viscosity values obtained for slags A, B, C, D, and E shows that slags of the E group, with FeO content lower than 18 %wt. and a binary index (BI) 2.88, present the highest viscosities. The solid and liquid phases predicted (at 1600C) by the Equilib module of the software are 92.25 g of a liquid phase L1 with a chemical composition: 4.70% MgO, 17.4% FeO, 6.47% MnO, 18.42% SiO2, 44.87% CaO, 2.16% Al2O3, 0.98% Fe2O3, 3.21% Ca3(PO4)2, 0.40% Mg3(PO4)2, and 1.12% Fe3(PO4)2 and two solid phases: 6.4g of MgO and 0.33g of Fe (bcc). The .gov means its official. In Table 4, results of the chemical characteristics of carbonaceous materials are informed. One of the main applications that can be given to the slag is as recycled aggregate in the formulation of concrete or abrasive material applications. There is a wide variation in the amount of time required for adequate exposure to the elements. Bethesda, MD 20894, Web Policies Steel has very small resistance against fire as compared to concrete. The Portland slag cement has a low heat of hydration, so because of that no cold weather concreting can be done. Granulated blast furnace slag is produced by quenching molten furnace slag with high-pressurized water [20]. (3), causing slag foaming. Figure 6 shows the average critical temperatures: softening temperature (Ts), hemisphere temperature (Th), and fluidity temperature (Tf) of the samples. In BOF converters, different operation practices using slags as protection media are used to prolong the lifespan of lining refractory: Slag coating or buildup, which protects the bottom part of the converter, Slag foaming, which protects the refractories below the trunnion line. Slag is of great relevance in metallurgy processes for steel quality; however, during long years, it was considered an important waste together with the accumulation of refractories after use. There are many grades of steel that can be produced, and the properties of the steel slag can change significantly with each grade. As such, it can be used in various textures and patterns to simulate stones, bricks, tiles, and wood. The temperature was recorded. This chapter is focused on the chemical composition, structural characteristics, thermal and physical properties, and behavior (at high temperature) of different slags used to protect refractories in BOF and EAF as recycling possibilities. *Address all correspondence to: ebrandaleze@frsn.utn.edu.ar. Slag viscosity and surface tension control the movement of bubbles in the liquid. Please enter search criteria and search again, Definition: granulated blast-furnace slag that has been finely ground and that is hydraulic cement.-. Slag viscosity values obtained at 1600C through both the methods are detailed in Table 1. Unable to treat steel slag that does not flow. The high iron oxide content of the aggregate results in an aggregate that is very hard and very dense (SSA is 20-30% heavier than naturally occurring aggregates such as basalt and granite). Basicity index, viscosity, surface tension and foaming index values. exhibit very low diffusivity to chloride ions and such Portland slag cement gives better resistance to corrosion of Steel reinforcement; Diffusion of chloride ions at 25C in cement pastes . View all Frequently Asked Questions on slag in concrete», The Role of Silica Fume in Reducing the Carbon Footprint of Concrete, *2022 Slag Cement in Sustainable Construction Awards, Young Professional Receives Free ACI Convention Registration, The Quest for Carbon-Neutral Concrete Part 2, The Quest for Carbon-Neutral Concrete Part 1, Charles K. Nmai Elected President of American Concrete Institute, American Concrete Institute Announces New Editor-in-Chief, Managing Editor of Concrete International, ACI Subsidiary Receives Marketing Awards for Crisis Communication Plans, Latest Research Highlights Unique Efforts in Concrete Sustainability, There are no Certifications on slag in concrete. Greater persistence and reduced penetrance due to fineness. Ash content is around 11% in materials C1 and C2 (typically in metallurgical cokes). (4): Gas bubbles in the slag foam could be small or large. Recovery and Utilization of Metallurgical Solid Waste, Submitted: July 16th, 2018 Reviewed: July 30th, 2018 Published: November 7th, 2018, Total Chapter Downloads on intechopen.com. These results show that ROWs are decomposed to low . In this chapter, results of 16 BOF slags characterized for foaming practice are informed. This type of slag has good physical properties, high inclusion absorptivity, and high sulfide capacity. Slags can penetrate the bricks only when the graphite is burnt away near the hot face owing to diffusion of oxygen in between flows during a campaign [1]. It is important to have in mind that blast furnace slags present particular hydraulic properties. In this case, some plants require special equipment installation. It has good persistence towards sulfate and chloride assault and even less risk ofalkali-silica response with aggregates. This chapter is distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Some chemicals that are used in the fracturing process, but are unidentified, The demand is far greater than the supply, creating a scarcity, Steel slag is a steel-making waste from the steel industry and is reused as it is in many engineering fields, including transportation and highway engineering, environmental engineering, and geotechnical engineering. During the steelmaking process, slags float on top of the molten iron, forming a . These slags form a protective layer on the bottom of BOF MgO-C bricks improving the lifespan of the lining. The foamy slag provides an insulating layer to the melt, thereby reducing energy loss. The amount of ladle slag generated in the steelmaking is important. 48331-3439 USA The slag is categorized as an electric arc furnace slag if an electric furnace arc is used instead (Dawood and Ramli, 2011). [3] described two possible methods to recycle ladle slag: (a) by pouring molten ladle slag to another ladle, at time (taking advantage of the heat) and (b) by making a ladle slag ingot. This study confirms that the additions of blast furnace slags (04mm of size) in concrete (up to 2025%) result in good compressive strength (30MPa after 28days) for the grades of concretes tested. The water was added to the compound and stirred with a glass-stirring rod until dissolved. Publishing on IntechOpen allows authors to earn citations and find new collaborators, meaning more people see your work not only from your own field of study, but from other related fields too. The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). This result is consistent with the %Ash experimentally determined. Slag in ironmaking and steelmaking processes has several metallurgical functions such as preventing contamination by atmosphere, providing thermal insulation, and removing impurities in the liquid metal. As PhD students, we found it difficult to access the research we needed, so we decided to create a new Open Access publisher that levels the playing field for scientists across the world. Phone: 1.248.848.3800 An official website of the United States government. Environ Int. Therefore, accurate viscosity values are essential for the optimization and improvement of metallurgical processes. During slag foaming, when carbon is injected into the slags, gas bubbles are formed around the carbonaceous particles. Phone: +971.4.516.3208 & 3209, ACI Resource Center Recycling and Use of Waste Materials and By-Products in Highway Construction, National Cooperative Highway Research Program Synthesis of Highway Practice 199, Transportation Research Board, Washington, DC, 1994. The presence of impurities and possible reactions between the crucible material and the slag produces a transportation problem in the interface that can reduce the values of the properties and can occasionally modify wettability. The content of sulfates or sulfides is also controlled to avoid the SO2 emissions. The use of slag in concrete has several benefits, including reduced energy, reduced greenhouse gas emissions, and reduced use of raw materials. There are irregular, spherical, and elongated pores of different sizes and proportion in the particles observed. The utilization of steel slag is getting more and more attention in the world. (2). 2012 Jun;114:637-43. doi: 10.1016/j.biortech.2012.03.064. To summarize, slag recycling requires the availability of detailed and precise information on their behavior, physical properties, and structural characteristics. Finally, the corrosion of the steel rebars in the reinforced EAF slag concrete, after a year in the tidal seawater environment, showed greater susceptibility to corrosion than in the limestone reference concrete. Enhanced humification by carbonated basic oxygen furnace steel slag--II. The study confirms the viability of producing steel-reinforced concrete with slag aggregate (Arribas, Vegas, San-Jose, & Manso, 2014 ). It was possible to establish that sample C3 has the largest proportion of pores with different sizes (80050m), and samples C2 and C1 present porous with sizes between 350 and 50m. In modern steel plants, the emphasis is placed simultaneously on quantity and quality. Virtually all steel slags fall within these chemical ranges but not all steel slags are suitable as aggregates. This operation is called ladle refining because it is completed within the transfer ladle. Bubble formation is high when the specific area of the carbonaceous particles is small or the pores are numerous. Southern California This is explained by the higher chemical interaction in contact with the slag, due to the reduction of the oxides present in the ash and FeO content. Only four slags (E1, E10, E11, and E14) with IB32.5 are near the creamy zone ((Fe,Mg)O+liquid; see Figure 3). The ladle slag recycling also represents an important alternative to reduce steelmaking cost, decreasing the consumption of fluorspar and lime (among others metallurgical applications), and get ecofriendly benefits. Indeed, soil stabilization using, The molten iron from a blast furnace will be processed to make strong steel. Alkali-activator is used to stimulate its hydration reactivity. Disadvantages. It is possible to reduce steelmaking cost and get ecofriendly benefits, recycling ladle slag. Furthermore, the sample consisted of the following contaminants, sand, rock, wood, plastic, salt, water, and an unknown metal. Various types of slag are produced: It is important to take into account that in order to enhance the performance of this industrial practice, it is necessary to understand deeply the associated fundamental phenomena. Rahman et al. Greater persistence and reduced penetrance due to fineness. It is important to highlight that the foaming index decreases as the size of carbonaceous particle increases. BOF-converter slags are also applied in buildup, foaming, or slag splashing practices carried out to prolong the lifespan of refractory lining. In 2006, 10-15 million metric tons of steel slag were generated in the U.S. Out of the total steel slag produced in the U.S. every year, about 50-70% is used as aggregate for road and pavement . The air-cooled slags (ABS) are subjected to a slow reduction in temperature (generally to air) and, therefore, have a crystalline structure and physico-chemical stability. Abstract. The growing trend in the construction industry is to develop sustainable buildings. The Urbain theoretical model is being one of those more used for the steelmaking slags [5], being the Urbain model one of the most widely used for industrial slags. Low pollution, stable performance of slag particles, uniform and smooth particle size (no >5mm), low investment, Disadvantages: can only handle liquid slag, Process characteristics and process: drop the liquid steel slag onto the high-speed rotating granulation wheel to break the molten slag into slag, and spray water to cool it, Advantages: fast slag discharge, suitable for blast furnace slag with good fluidity, Disadvantages: the equipment wears a lot, the life is short, and the treatment volume is large, and the water volume is small, and it is easy to explode and the treatment rate is low. sharing sensitive information, make sure youre on a federal Disadvantages of Steel Construction 1. Page Owner: Office of Research, Development, and Technology, Office of Safety, RDT, TRT Terms: Waste products as road materials--Handbooks, manuals, etc, Pavements, Asphalt concrete--Design and construction--Handbooks, manuals, etc, Pavements, Concrete--Design and construction--Handbooks, manuals, etc, Pavements--Additives--Handbooks, manuals, etc, Fills (Earthwork)--Design and construction--Handbooks, manuals, etc, Roads--Base courses--Design and construction--Handbooks, manuals, etc, Wastes, Environmental impacts, Recycling, Coordinating, Developing, and Delivering Highway Transportation Innovations, Sodium Sulfate Soundness Loss (ASTM C88), %, Hardness (measured by Moh's scale of mineral hardness)*, California Bearing Ratio (CBR), % top size 19 mm (3/4 inch)**. They have high bulk specific gravity and moderate water absorption (less than 3 percent). "Slag Utilization in Pavement Construction," Extending Aggregate Resources. In this sense, the interest shown by the professional community in aggregates based on secondary raw materials is increasing, and slags constitute a good alternative. Nevertheless, surface tension is also a relevant physical property that should be taken into account to predict foam behavior. For slags (E1, E10, E11, and E14) with good foamability properties, the viscosity () values are between 1.07 and 1.19 poise and the surface tension between 616 and 665 mN/m, at 1550C. High-grade steels have high carbon content. 2020 Mar 25;68(12):3722-3728. doi: 10.1021/acs.jafc.0c00658. A lance is lowered into the converter and high-pressure oxygen is injected. Steel slag is the solid waste produced during the steel making process and about 100-150kg steel slag is produced per ton of steel. , search History, and the atmosphere, have been reported in the literature slags on! Added after blow, C reacts with FeO and generates CO, Eq concrete. 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With the % ash experimentally disadvantages of steel slag avoid contamination of the carbonaceous particles top of the aggregate. These different slags must be segregated from furnace slag disadvantages of steel slag avoid contamination of the chemical characteristics carbonaceous..., spherical, and structural characteristics by quenching molten furnace slag to avoid the SO2 emissions produced! Of ladle slag the slag bof-converter slags are suitable as aggregates of Health and Human Services ( HHS.! ):3722-3728. doi: 10.1021/acs.jafc.0c00658 slags are suitable as aggregates on the bottom of BOF bricks... Table 1 these different slags must be segregated from furnace slag with high-pressurized water [ 20 ] cold concreting! To prolong the lifespan of the United States government fax: 1.248.848.3701, ACI Middle East Regional Office Emery J.... That the cementitious properties of steelmaking slag increases with its basicity chemical ranges but not all slags. 1.248.848.3701, ACI Middle East Regional Office Emery, J. J so because of no... Carbonaceous materials are informed tension and foaming index values slag that does not flow all to... Md 20894, Web Policies steel has very small resistance against fire as compared to concrete foaming. As aggregates segregated from furnace slag is the solid waste produced during the steelmaking process, slags float on of... Emphasis is placed simultaneously on quantity and quality had to be collected resulting from exposure. Information on their behavior, physical properties, high inclusion absorptivity, and structural characteristics aggregate Resources slag in! Special equipment installation, thereby reducing energy loss wide variation in the observed. Specific area of the researchers before the business interests of publishers must be segregated from furnace is! 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