two main disadvantages. Due to the white color of GGBFS, the cement color obtained is brighter colored when compared to conventional cement. ISD (%MgO-%FeO) for three ternary basicity index ranges. Slag foaming constitutes another alternative to use the converter slags to protect MgO-C bricks below the trunnion line [8, 10]. The study confirms the viability of producing steel-reinforced concrete with slag aggregate (Arribas, Vegas, San-Jose, & Manso, 2014 ). Different experimental tests applied in slag characterization are also detailed. The growth of the arc furnace-based steel industry has been encouraged by modern arc furnaces of large capacity and ultra-high power, electrical efficiency improvement, and metallurgical efficiency through oxygen lancing or the co-jet technology. The most commonly used alkaline activators are sodium hydroxide, potassium hydroxide, sodium water glass, and potassium water glass. Guilherme Constantino Meirelles, Anelisa de Aquino Vidal Lacerda Soares, If a carbonaceous material is added after blow, C reacts with FeO and generates CO, Eq. Nevertheless, when ISD includes the %MnO, the same four slags (E1, E10, E11 and E14) are moved toward the right showing the MnO effect (Figure 4). Senani et al. Then, the pipet was rinsed with distilled water. FOIA The oxygen combines with and removes the impurities in the charge. Date:11/30/2022, Publication:Materials Journal The cementing properties of activated steel slag using alkaline are higher than those of raw steel slag due to the chemical reactions between the steel slag and sodium hydroxide (NaOH). Drainage phenomena decrease the thickness of the liquid separating film to values lower than 1m. Mainly, it is used as an aggregate in asphalt and concrete . 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. So that resistance against severe conditions increases. The heat retention characteristics of steel slag aggregates can be advantageous in hot mix asphalt repair work in cold weather. 2 . [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. As it is known, converter slags are an extremely complex mix of oxides that determine the slag physical properties such as viscosity, density, surface tension, and others. The size of the bubbles determines the foam behavior. Another contribution of this work is the information concerning different carbonaceous materials used to foam BOF slags. Steel slag aggregates are highly angular in shape and have rough surface texture. Measured oxygen activities in steel bulk, which varied between 3.5-6 ppm, were compared to predicted oxygen activities. 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. A new concept considers to use the waste of one industry as a resource in another industry. This is the major source of steel slag aggregate. The processing of steel slags for metals recovery is not only important to remove excess steel at the market source for reuse at the steel plant, but is also important to facilitate the use of the nonmetallic steel slag as construction aggregate. 202-366-4000, Federal Highway Administration Research and TechnologyCoordinating, Developing, and Delivering Highway Transportation Innovations. Please enter this 5 digit unlock code on the web page. 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). Chemical and mineralogical composition of Portland cement. "Slag Utilization in Pavement Construction," Extending Aggregate Resources. Boron leaching; composting; degree of humification; humic acid; steel slag. Once cooled, the ABS is crushed and sieved according to the geometric characteristics required by the application. The content of sulfates or sulfides is also controlled to avoid the SO2 emissions. FeO content in the slag constitutes a variable that enables to control slag foaming. Contact our London head office or media team here. The chemical and mineralogical composition of Portland cement is detailed in Table 5. As such, it can be used in various textures and patterns to simulate stones, bricks, tiles, and wood. Slag behavior at process temperatures depends on slag chemistry, melting behavior, viscosity, surface tension, fluidity, FeO content, and MgO saturation. However, it is relevant to highlight that ladle slag reuse promotes dephosphorization reaction at BOF and can substitute expensive steelmaking agents, and besides, the process can be more ecofriendly. Along the steel conversion process, the oxygen blown is mostly combined with elements dissolved in the melt. ACI World Headquarters Table 18-3. 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. It is important to note that sulfur additions suppressed slag foaming and tended to increase the size of CO gas bubbles. Fig 1: Extraction of molten Slag from Blast Furnace. Download scientific diagram | The two main ways of the slag entrainment in the simulation: (a) horizontal back-flow toward the SEN and upper-flow toward the free surface. Tufa is a white, powdery precipitate that consists primarily of calcium carbonate (CaCO3). Table 2 details the chemical composition of the BOF slags selected for the study in order to improve the foaming process. Disadvantages of Structural Steel Structures. [19] informed that metallurgical cokes (such as materials C1 and C2) promote gas emissions one order higher (in magnitude) than the synthetic coke. Furthermore, the sample consisted of the following contaminants, sand, rock, wood, plastic, salt, water, and an unknown metal. During ladle refining, additional steel slags are generated by again adding fluxes to the ladle to melt. Another possibility is the use of steel slag as a binder or filler replacement in composite materials in civil engineering production. The mentioned uses include an exhaustive control of the content of Ba, Cd, Cr, Mo, Ni, Pb, V, and Zn, in order to avoid contamination or air pollution. Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete. Steel Slag Aggregates Use in Hot Mix Asphalt Concrete. Disadvantages of Blast-Furnace Slag Cement - Air-cooled blast-furnace slagThe material resulting from solidification of molten blast-furnace slag under atmospheric conditions; subsequent cooling may be accelerated by application of water to the solidified surface. Slag with low FeO and high MgO is desirable. In this chapter, techniques for the treatment and recycling of metallurgical slags are described. In the basic oxygen process, hot liquid blast furnace metal, scrap, and fluxes, which consist of lime (CaO) and dolomitic lime (CaO.MgO or "dolime"), are charged to a converter (furnace). Furthermore, the ash content of materials C1 and C2 allows predicting rapid gas generation, which is not favorable for foam stability. Emery, J. J. Among these chemicals, NaOH arguably finds the widest use in industrial applications. In addition, the assumptions of a sulphur-oxygen equilibrium between steel and slag and the dilute solution model for the liquid steel phase were utilized in the calculations. Date:11/10/2022, Search all Articles on slag in concrete », Publication:Concrete International The steel slags produced at this stage of steel making are generally referred to as raker and ladle slags. This requires extra cost and special care. This information represents a good starting point to optimize the BOF foaming industrial practice. Choi et al. Poor steel slag stability, Process characteristics and process: The high-temperature liquid slag is divided and crushed by the pressure water during the process of flowing out and falling. The former method of recycling ladle slag is pouring the molten slag from a ladle to another or making ladle slag ingot [3]. Midwest, Feedback via Email The reaction between FeO present in the slag and carbon is strongly endothermic. Bookshelf Federal Highway Administration In this chapter, two main slag practices are described: slag coating and slag foaming considering experimental data and theoretical information. User Guidelines for Waste and Byproduct Materials in Pavement Construction. These different slags must be segregated from furnace slag to avoid contamination of the slag aggregate produced. London, SW7 2QJ, The Comprehensive Utilisation of Red Mud Utilisati High Temperature Physicochemistry Group, Metallurgy Department, DEYTEMA Center, Universidad Tecnolgica Nacional, Facultad Regional San Nicols, San Nicols, Argentina. 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. Ash content is around 11% in materials C1 and C2 (typically in metallurgical cokes). Next, a 100 mL graduated cylinder was used to measure 60 mL of distilled water. Tufa precipitates have been reported to clog drainage paths in pavement systems.(5). There are irregular, spherical, and elongated pores of different sizes and proportion in the particles observed. Feb 23, 2023 (The Expresswire) -- Report Insights: The Global Iron and Steel Slag market is valued at 964.4 million USD in 2020 is expected to reach 1156.6. To control foam height, carbonaceous particles can be added to slag with adequate size and low volatile content. The experiment needed a metal wire that was dipped into the solution, Both men were effective and manufactured extensive processing plants for creating wellsprings. The slag occurs as a molten liquid melt and is a complex solution of silicates and oxides that solidifies upon cooling. Different steel plants, depending on their lay out, process conditions, and operation, have developed and implemented various techniques for protecting MgO-C refractory lining: brick patching, gunning, manual splashing, chemical splashing, slag coating, slag foaming, and slag splashing [1, 4]. Poor steel slag stability Panning method Process characteristics and process:Pour the hot molten slag into the slag pot and transport it to the side of the slag tray. 2012 Jan;104:497-502. doi: 10.1016/j.biortech.2011.11.021. This metals recovery operation (using magnetic separator on conveyor and/or crane electromagnet) is important to the steelmaker as the metals can then be reused within the steel plant as blast furnace feed material for the production of iron. In addition, solid and liquid phases of the slag (at practice temperatures) in the system have relevant influence on the adherence behavior. Environ Sci Pollut Res Int. The copper complexation ability of a synthetic humic-like acid formed by an abiotic humification process and the effect of experimental factors on its copper complexation ability. Slag-refractory adherence mechanisms are analyzed, and measurements of slag fluidity at high temperature and other physical properties obtained by thermodynamic simulation (up to 1700C) are informed. Pit slag and clean out slag are other types of slag commonly found in steel-making operations. After that, the Erlenmeyer flask was filled with 100 mL of distilled water. It was observed that when the bubbles present a DB=0.005mm (small size), MnO content (for MnO<8%) results in random foaming index values compared to the effect of FeO content. Indeed, soil stabilization using, The molten iron from a blast furnace will be processed to make strong steel. The site is secure. The slag processor may also be required to satisfy moisture content criteria (e.g., limit the amount of moisture in the steel slag aggregate prior to shipment to a hot mix asphalt plant) and to adopt material handling (processing and stockpiling) practices similar to those used in the conventional aggregates industry to avoid potential segregation. and a binary index (BI) 2.88, present the highest viscosities. Greater persistence and reduced penetrance due to fineness. In the places vulnerable to attacks of chloride and sulfate such as sub-structure and marine structures. Disadvantages Of Steel Slag 2312 Words10 Pages 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. from publication . Collins, R. J. and S. K. Ciesielski. Limit the search results modified within the specified time. . Would you like email updates of new search results? The slag is categorized as an electric arc furnace slag if an electric furnace arc is used instead (Dawood and Ramli, 2011). Further, this slag is grounded finely as that of cement and diverse in the amount as per the requirement. Due to this property, this type of cement can be used where the problem of thermal cracking is foreseen. Steel scrap is the preferred metallic charge material, and sponge iron is also used regularly in most plants in order to dilute tramp elements introduced through the scrap [1, 17]. Figure 6 shows the average critical temperatures: softening temperature (Ts), hemisphere temperature (Th), and fluidity temperature (Tf) of the samples. sharing sensitive information, make sure youre on a federal Efforts are on for economic use of all types of steel plant wastes, such as slag, dust, and flue gases [1]. The addition of blast furnace slag into cement avoids a part of limestone and coal extraction and makes it possible to diminish the CO2 emissions that cause environment pollution. Restricted position: A lance is lowered into the converter and high-pressure oxygen is injected. Date:9/1/2022, Publication:Concrete International Also, a good adherence behavior on MgO-C samples was obtained by means of dipping tests. Levels for leaching boron from composts prepared by adding slag (0.2-0.4 mg L-1) were obviously higher than the corresponding levels without slag (0.05 mg L-1). This is another alternative to avoid the risk of slopping. Blast Furnace Slag (BFS) cement is the combination of Ordinary Portland Cement (OPC) and fine Granulated Blast Furnace Slag (GBFS) gained as a byproduct in the steel making manufacturer with below 70% to that of cement. Another type of slag that is produced in considerable quantity (ton/year) by the steelmaking industry is ladle slag. Muscat, Sultanate of OmanWhatsApp: +96898254446, Phone: +96898254446Email: [emailprotected]Web: arijco.com, Penetration Grade Bitumen | Viscosity Grade (VG) Bitumen | Performance Grade (PG) Bitumen | Polymer Modified Bitumen (PMB) | Bitumen Emulsion | Oxidized Bitumen | Cutback Bitumen. Transient foams last for a few seconds, while stable foams have prolonged shelf life [12]. Epub 2011 Nov 16. Increasing the steel slag content improved the drying shrinkage resistance but was not conducive to the temperature shrinkage resistance. These materials must be source separated, and well-defined handling practices must be in place to avoid contamination of the steel slag aggregate. Email Address is required Search results must be an exact match for the keywords. The presence of carbon controls slag penetration and chemical attack. 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. Box 1886, PC 133, 2nd Floor,Tower 5, Panorama Mall. All these activators have some common properties: caustic, corrosive, and highly hazardous. Baking soda and citric acid mixed when dropped in the water, which causes a chemical reaction to happen. Date:1/16/2023, Publication:Materials Journal Basicity index, viscosity, surface tension and foaming index values. Slags of appropriate characteristics allow lining recovery, reducing corrosion damage, oxidation, and erosion of the refractory, as well as the impact of the charge, without altering the metallurgical function of the BOF. The application of MgO saturated coating slags helps to reduce the impact of the BOF operation on the refractory lining. Carbonaceous materials also exert an effect in the foaming practice; it is possible to recommend the addition of petroleum coke (material C3) in the foaming practice, because of its ash low content, high proportion of large pores, and higher carbon content. Bethesda, MD 20894, Web Policies An increase in silica concentration promotes lower surface tension of slag and leads to smaller CO gas bubbles and their easier escape from the slag. [21] informed that concrete with crystallized slag sand addition presents good physical and mechanical properties. It is not good for the environment and energy saving. The slag processor must also be aware of the general aggregate requirements of the end user. Enhanced humification by carbonated basic oxygen furnace steel slag--II. The lumpy form I am now in is loaded into a blast furnace which turns me into a molten metal. If a converter is used in the steel-making process, with water being sprayed on the slag for cooling purpose, the slag generated is termed a converter slag. The coating and foaming practices are very useful in BOF converters and EAF. 2020 Mar 25;68(12):3722-3728. doi: 10.1021/acs.jafc.0c00658. Tufalike precipitates, resulting from the exposure of steel slag aggregates to both water and the atmosphere, have been reported in the literature. The use of blast furnace slag as artificial rocks is also possible because they are similar to semi-hard stones. Please enter search criteria and search again, Definition: granulated blast-furnace slag that has been finely ground and that is hydraulic cement.-. I am now in the form of sinter after going through the smelter. The relative proportions of these compounds depend on the steel-making practice and the steel slag cooling rate. Virtually all steel slags fall within these chemical ranges but not all steel slags are suitable as aggregates. After being tapped from the furnace, the molten steel is transferred in a ladle for further refining to remove additional impurities still contained within the steel. Different percentage of GGBFS is added for a different type of construction. Please provide design data for special processing requirements. Greater persistence and reduced penetrance due to fineness. Both properties (viscosity and surface tension) are necessary to estimate the foaming index and to increase the knowledge about this practice. High heat generation also results in thermal cracking of the welded areas. In agreement with BOF foaming practice, the rate of gas generation was found to be an important parameter in carbon-slag interactions and needs to be optimized to maintain optimum levels/duration of gas entrapment by the slag and foaming behavior. One of the biggest challenges for metallurgists is to recycle the slag directly in the steelmaking processes. used. However, there are some disadvantages such as high shrinkage, formation of micro-cracks and rapid setting. Steel production necessarily involves production of millions of tons of slag as well as waste gases containing harmful constituents such as carbon dioxide, dioxin, and furans. Two types of foams can be distinguished: (i) foams initially formed by spherical bubbles that are separated by thick films of liquid and (ii) polyhedral foams in which the bubbles are deformed because of drainage of the liquid film [9, 10, 11, 12]. They are produced at high temperatures, and under fast-cooling rates, the structure obtained is amorphous. The injection of oxygen and carbonaceous materials in industrial EAF furnaces creates highly dynamic and nonsteady state conditions. Unable to load your collection due to an error, Unable to load your delegates due to an error. Process characteristics and process: use the sensible heat of high temperature liquid slag to sprinkle water to produce physical and mechanical effects and the hydrolysis of free calcium oxide to fragment the slag, Advantages: simple process, suitable for processing high basicity steel slag, steel slag has high activity, good stability, and can handle solid slag, Disadvantages: uneven particle size, subsequent crushing, large processing volume, long processing cycle, Process characteristics and process: When the slag is higher than the quenchable temperature, spray with limited water to the slag, so that the temperature stress generated by the slag is greater than the ultimate stress of the slag itself, resulting in fragmentation, and the hydration of free calcium oxide causes the slag to be further cracked, Advantages: fast slag discharge speed, short cooling time, convenient for mechanized production, large processing capacity; high steel slag activity, high productivity, Disadvantages: large equipment loss, large area, large crushing dust, large steam volume; large processing volume of steel slag. Prior to its use as a construction aggregate material, steel slag must be crushed and screened to meet the specified gradation requirements for the particular application. Finally, lumps of slags could be added in BOF to improve dephosphorization. Modern LD converters are lined with MgO-C refractories. The model estimates the viscosity of liquid silicates and alumino-silicates in function of chemical composition and describes temperature dependence of viscosity through the Weymann expression, Eq. Lais Lorena Queiroz Moreira, Leonardo Theodoro Bll and For slags with FeO25.8%wt, MgO7%wt., CaO44%wt., Al2O31%wt., and SiO214%wt., the liquid phase L1 increases up to 97g, and the chemical composition is as follows: 4.33% MgO, 24.2% FeO, 6.16% MnO, 14.45% SiO2, 43.8% CaO, 1.03% Al2O3, 1.23% Fe2O3, 2.82% Ca3(PO4)2, 0.33% Mg3(PO4)2, and 1.40% Fe3(PO4)2. Samitinjay S. Bansode, in Characteristics and Uses of Steel Slag in Building Construction, 2016 4.6 Slag applications in road constructionpavement structure.
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