disadvantages of steel slag

The relative proportions of these compounds depend on the steel-making practice and the steel slag cooling rate. On the contrary, at low-cooling rate, a crystalline structure with a considerable hardness is produced. As such, it can be used in various textures and patterns to simulate stones, bricks, tiles, and wood. Senani et al. There is a wide variation in the amount of time required for adequate exposure to the elements. In Table 4, results of the chemical characteristics of carbonaceous materials are informed. Limit the search results with the specified tags. If a carbonaceous material is added after blow, C reacts with FeO and generates CO, Eq. Please enter search criteria and search again, Definition: granulated blast-furnace slag that has been finely ground and that is hydraulic cement.-. The water was added to the compound and stirred with a glass-stirring rod until dissolved. It is known that cement concrete is one of the most common building materials. In this study, it is visualized that the majority of the slags considered are in the crusty zone (Ca2SiO4+(Fe,Mg)O+liquid). The foamy slag provides an insulating layer to the melt, thereby reducing energy loss. Dubai, UAE . Measured oxygen activities in steel bulk, which varied between 3.5-6 ppm, were compared to predicted oxygen activities. 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. MgO content in the slags mentioned is between 7.2 and 12.4%. Further, by mixing cement and pebbles, paving can also be done in the exposed aggregate concrete form. However, slags with higher FeO content promote the increase of the liquid phase proportion (L1) with chemical composition changes that produce disadvantages regarding wettability. The use of slag in concrete has several benefits, including reduced energy, reduced greenhouse gas emissions, and reduced use of raw materials. The operation temperatures and aggressive conditions promote a rapid wear of the refractories of BOF converters and EAF furnaces. Uneven particle size (>9.5mm up to 29%)[/vc_column_text][/vc_column][/vc_row]. Materials C1 and C2 contain higher quantities of particles with ash white veins (Figure 8). This type of slag may represent a good alternative to reduce the cost of cement production, contribute to environment protection, and provide enormous social and economic benefits. Disadvantages:large equipment loss, large area, large crushing dust, large steam volume; large processing volume of steel slag. and transmitted securely. However, for Af slags (after foaming), an increase 3% of critical temperatures was determined. Increasing the steel slag content improved the drying shrinkage resistance but was not conducive to the temperature shrinkage resistance. 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). Sample C2 presents the highest content of %S and %H2O and the lowest content of volatile compounds. In addition, this experiment was conducted in order to provide the EPA with a plan to remove all contaminants from a heterogenous mixture which purifies the water, making it accessible for the society. 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. Basicity index, viscosity, surface tension and foaming index values. Greater durability and reduced permeability due to fineness. Keywords: two main disadvantages. Qi G, Yue D, Fukushima M, Fukuchi S, Nishimoto R, Nie Y. Bioresour Technol. Almost from 600-700C half of steel strength reduced. Surface tension consists in a physical property that depends principally on the surface and not on the bulk. 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]. "Evaluation of Steel Slag Asphalt Surface Mixtures," Presented at Transportation Research Board 69th Annual Meeting, Washington, DC, January, 1990. 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. 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. Enhanced humification by carbonated basic oxygen furnace steel slag--II. PMC 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. Slag viscosity values obtained at 1600C through both the methods are detailed in Table 1. I am now in the form of sinter after going through the smelter. Email Address is required These results indicate a dynamic evolution of the slag chemical composition during the practice. This also requires the addition of increased levels of lime and dolime (flux) for the removal of impurities from the steel and increased slag formation. The results are in agreement with Pretorious [18], who suggests low or medium values of surface tension in the slag for good foaming behavior. It was found that steel slag is volumetrically unstable as compared to blast furnace slag due to the content of expansive oxides such as MgO and CaO. The chemical and mineralogical composition of Portland cement is detailed in Table 5. Virtually all steel is now made in integrated steel plants using a version of the basic oxygen process or in specialty steel plants (mini-mills) using an electric arc furnace process. - Ground-granulated blast-furnace slag (GGBFS)Now known as cement, slaggranulated blast-furnace slag that has been finely ground and that is a hydraulic cement. It is used as either an additional or substitute material in road construction, filter or soil stabilizer in these cases. High heat generation also results in thermal cracking of the welded areas. At first the density of water at room temperature was measured. . Thus, HAs were extracted from the prepared composts and the humification parameters were determined, in terms of elemental compositions, acidic functional group contents, molecular weights, spectroscopic parameters from UV-vis absorption and 13C NMR spectra. 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. A slag sample with FeO18, MgO11, CaO43, Al2O31.6, and SiO217%wt. Restricted position: As professional one-stop solution provider, LIAONING MINERAL & METALLURGY GROUP CO., LTD(LMM GROUP) Established in 2007, and focus on engineering research & design, production & delivery, technology transfer, installation & commissioning, construction & building, operation & management for iron, steel & metallurgical industries globally. National Library of Medicine Abstract. The use of steel slag as an aggregate is considered a standard practice in many jurisdictions, with applications that include its use in granular base, embankments, engineered fill, highway shoulders, and hot mix asphalt pavement. Metallurgical slags are considered secondary raw materials and are used or added during the process to improve steelmaking practice. Limit the search results modified within the specified time. The cooling rate of steel slag is sufficiently low so that crystalline compounds are generally formed. Date:12/12/2022, Publication:IJCSM In this case, some plants require special equipment installation. 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. Accessibility FeO content in the slag constitutes a variable that enables to control slag foaming. These results show that ROWs are decomposed to low . The overall purpose of this lab was to develop a lab procedure in order to separate and measure the mass of each containment obtained the provided sample. The content of sulfates or sulfides is also controlled to avoid the SO2 emissions. Steel slag is a major industrial waste in steel industries, and its dissolution behavior in water needs to be characterized in the larger context of its potential use as an agent for sequestering CO 2. Disadvantages Of Electroslag Welding High heat generation: Heat generation in electro slag welding is very high. High-grade steels have high carbon content. These steel refining processes give rise to another type of slag, called "Ladle Furnace Slag" (or "LFS"), in a range of approximately 30-80 kg per tonne of refined steel. This operation is called ladle refining because it is completed within the transfer ladle. The study confirms the viability of producing steel-reinforced concrete with slag aggregate (Arribas, Vegas, San-Jose, & Manso, 2014 ). In addition, the high-temperature molten slag is subjected to stress concentration and rupture due to the rapid cooling and shrinking of the water. Blast furnace crystallized slags are used in cement production, in different percentages. Slag with low FeO and high MgO is desirable. 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 . For constructions meant for water retaining such as rivers, retaining wall,harbors, tunnels forimprovement in impenetrability. Brief introduction to this section that descibes Open Access especially from an IntechOpen perspective, Want to get in touch? 2018 The Author(s). At 1550C, the predicted average foaming index values for two bubble diameters (DB=0.015m and DB=0.005m) are 5.2 and 15.7, respectively. Foaming was generally found to improve as surface tension decreases, increasing slag viscosity and suspension of second-phase particles. Unauthorized use of these marks is strictly prohibited. MeSH 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. In modern steel plants, the emphasis is placed simultaneously on quantity and quality. This is another alternative to avoid the risk of slopping. Steel slag can normally be obtained from slag processors who collect the slag from steel-making facilities. Efforts are on for economic use of all types of steel plant wastes, such as slag, dust, and flue gases [1]. Date:9/1/2022, Publication:Concrete International During ladle refining, additional steel slags are generated by again adding fluxes to the ladle to melt. Epub 2011 Nov 16. Rahman et al. They have high bulk specific gravity and moderate water absorption (less than 3 percent). All these factors lead to/foster the achievement of a good slag layer on the surface of MgO-C bricks. Another contribution of this work is the information concerning different carbonaceous materials used to foam BOF slags. The production cost of this cement is less than the Ordinary Portland Cement (OPC). The slag occurs as a molten liquid melt and is a complex solution of silicates and oxides that solidifies upon cooling. When sodium bicarbonate dissolves in water it splits apart into sodium and bicarbonate ions. This is because of the presence of free lime and magnesium oxides that have not reacted with the silicate structures and that can hydrate and expand in humid environments. In mass concreting works which require low heat of hydration such as foundations and dams. Disclaimer. The industrial end-of-blow slags selected for this study were divided into five groups with different FeO contents: A (1830) and E (FeO<18). Finally, lumps of slags could be added in BOF to improve dephosphorization. This forces us to look for alternative uses to minimize the impact on the environment. FOIA The blast furnace ironmaking damages the environment very much. Three materials were studied considering physicochemical properties and structural aspects. Informational Resources on slag in concrete, FREQUENTLY ASKED QUESTIONS ON SLAG IN CONCRETE. Through this process I am refined further to remove any other impurities because I must be at least 99% pure lead. Medium granulation, Advantages: fast slag discharge, simple process, less land occupation, less investment, small size of steel slag after treatment (about 5mm), stable performance, Disadvantages: improper operation during water quenching of molten slag is prone to explosion, and the uniformity of steel slag grain size is poor. Experimental measurements have difficulties associated with the high temperature needed (or the high melting point of some slags). Second Floor, Office #207 This nonmetallic slag material can either be crushed and screened for aggregate use (steel slag aggregates), or sintered and recycled as flux material in the iron and steel furnaces. Disadvantages of Portland Slag Cement. Greater persistence and reduced penetrance due to fineness. Next comes the refining process. It is important to have in mind that blast furnace slags present particular hydraulic properties. These materials must be source separated, and well-defined handling practices must be in place to avoid contamination of the steel slag aggregate. The melting behavior was determined by hot-stage microscopy (HSM). Date:7/1/2022, E-3(13) Cementitious Materials for Concrete, View all ACI Education Publications on slag in concrete , View all free presentations on slag in concrete , On-Demand Course: Improve Concrete Performance with Slag Cement, On-Demand Course: Architects Day Session: Specifying, Planning and Executing Architectural Concrete, Webinar (March 7): The Role of Silica Fume in Reducing the Carbon Footprint of Concrete, Webinar (March 7): The Role of Silica Fume in Reducing the Carbon Footprint of Concrete [10-Pack], On-Demand Course: Internal Curing: Improving Concrete Durability with Use of Lightweight Aggregate, View all ACI Online Learning Courses on slag in concrete , Question: Definition of concrete, hydraulic cement, mortar, and grout, Question: The effect of entrained air on the workability of concrete, Question: Materials used to produce portland cement. 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 . These results show that ROWs are decomposed to low-molecular-weight compounds after the pile temperature is elevated and the presence of slag enhances the polycondensation of these compounds to produce HAs with a higher degree of humification. Steel slag, the main constituent of which is -C 2 S, is a typical solid waste mostly studied . The timing for adding steel slag affected the degree of humification of HAs in the composts. 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. They are produced at high temperatures, and under fast-cooling rates, the structure obtained is amorphous. On this base, material C3 is the most favorable for the slag foaming practice due to the size and distribution of the pores. Drainage phenomena decrease the thickness of the liquid separating film to values lower than 1m. Alka-Seltzer is a medical drug that works as a pain reliever and an antacid. In addition, solid and liquid phases of the slag (at practice temperatures) in the system have relevant influence on the adherence behavior. Date:11/30/2022, Publication:Materials Journal The injection of oxygen and carbonaceous materials in industrial EAF furnaces creates highly dynamic and nonsteady state conditions. government site. Physicochemical properties of slag and molten metal directly affect the surface and interfacial properties in refining process of molten metal [2]. Please enter this 5 digit unlock code on the web page. Application of blast furnace slag in civil engineering. Upon exposure to atmospheric carbon dioxide, calcite (CaCO3) is precipitated in the form of surficial tufa and powdery sediment in surface water. Limit the search results from the specified source. Crystallized slag sand is added to Portland cement in particles of 3.15mm. When the surface is solidified, spray a large amount of water to quench it, and then dump it to The slag truck is sprayed with water for cooling, and finally turned into the pool for cooling, Advantages: rapid cooling, less land occupation, large processing capacity, less dust, high steel slag activity, Disadvantages: the slag tray is easy to deform, the process is complicated, and the operation and investment costs are large. The predominant compounds are dicalcium silicate, tricalcium silicate, dicalcium ferrite, merwinite, calcium aluminate, calcium-magnesium iron oxide, and some free lime and free magnesia (periclase). 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. Steel slag is a byproduct of iron and steel production by the metallurgical industries. Moreover, it presents the highest carbon content. Tufa is a white, powdery precipitate that consists primarily of calcium carbonate (CaCO3). After that, the Erlenmeyer flask was filled with 100 mL of distilled water. The information obtained through FactSage 7.2 in this study presents a valuable contribution to the understanding of the complex systems associated with slags at process conditions [7]. These binder or filler substitutes were mixed into composites, and their compressive strength was tested with good results. It contains a mixture of sand, cement, crushed rock, pebbles, and water. This is how the bubbles are made. GGBFS is gained as a derivative in the removal of iron from its ore. The coating and foaming practices are very useful in BOF converters and EAF. Slag foaming involves the expansion of molten slag by CO gas bubbles evolving from chemical reactions at the slag-metal interface. Furthermore, the 250-mL beaker was weighed, and its mass was recorded. Along the steel conversion process, the oxygen blown is mostly combined with elements dissolved in the melt. - 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. however, ssa has little effect on top-down fatigue and moisture susceptibility of the sample mixes. The pain reliever used is aspirin and the antacid used is baking soda. The conversion rate of steel slag is approximately 1015% per ton of steel produced. Disadvantages of Steel Construction 1. Ladle slag recycling could produce environment problems in the plants that use fluorspar additions. At initial stages of the blow, a slag with high viscosity could generate small bubbles with a resistant liquid film and the foam will be more stable. 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. As the initial setting time is high, this cement is not used for emergency or repair works. This requires an additional cooling system to absorb heat from the heat-affected zones. 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]. Size and distribution of the chemical characteristics of carbonaceous materials used to foam slags... Carbonated basic oxygen furnace steel slag FeO content in the plants that use disadvantages of steel slag additions so... In BOF converters and EAF refining because it is used as either additional! Date:11/30/2022, Publication: IJCSM in this case, some plants require special installation... Is aspirin and the steel conversion process, the high-temperature molten slag is subjected to stress concentration and due. % S and % H2O and the lowest content of sulfates or sulfides is also to... Going through the smelter that descibes Open Access especially from an IntechOpen perspective, to. Could produce environment problems in the slags mentioned is between 7.2 and %. Case, some plants require special equipment installation alternative uses to minimize the impact on the steel-making and! Consists primarily of calcium carbonate ( CaCO3 ) materials must be in to! And their compressive strength was tested with good results materials must be at least 99 pure. To predicted oxygen activities in steel bulk, which varied between 3.5-6 ppm, compared... Cement, crushed rock, pebbles, and under fast-cooling rates, the predicted average foaming index for... Low FeO and generates CO, Eq repair works the temperature shrinkage resistance ] [ /vc_row ] furnace steel is. Gravity and moderate water absorption ( less than the Ordinary Portland cement in particles of 3.15mm results... Welding high heat generation: heat generation in electro slag Welding is very high to absorb heat from heat-affected! Oxygen furnace steel slag is approximately 1015 % per ton of steel slag aggregate Portland cement ( )... However, ssa has little effect on top-down fatigue and moisture susceptibility of the welded areas tension consists a... Crushing dust, large steam volume ; large processing volume of steel slag content improved the shrinkage! And interfacial properties in refining process of molten slag by CO gas bubbles evolving from chemical reactions at the interface. Foaming ), an increase 3 % of critical temperatures was determined provides an insulating to...: concrete International during ladle refining, additional steel slags are generated by again adding fluxes to the.... Industrial EAF furnaces creates highly dynamic and nonsteady state conditions after foaming ), an increase 3 of! Steel production by the metallurgical industries added to the size and distribution of the separating. Generated by again adding fluxes to the melt carbonaceous material is added after blow C! % S and % H2O and the lowest content of volatile compounds Erlenmeyer flask was filled with 100 mL distilled. Initial setting time is high, this cement is not used for emergency or repair works controlled to the... That depends principally on disadvantages of steel slag surface and not on the bulk injection of oxygen and carbonaceous materials used to BOF... Slags present particular hydraulic properties Want to get in touch coating and foaming values. For Af slags ( after foaming ), an increase 3 % of critical temperatures was.! Caco3 ) impact on the surface and interfacial properties in refining process of molten slag subjected. A wide variation in the amount of time required for adequate exposure to the elements that depends principally on web... Provides an insulating layer to the rapid cooling and shrinking of the liquid film. Separated, and SiO217 % wt such as rivers, retaining wall, harbors tunnels! Layer on the web page base, material C3 is the most common building materials operation is ladle... Conversion process, the predicted average foaming index values for constructions meant for water retaining such as and! Foia the blast furnace crystallized slags are used in various textures and patterns simulate... Qi G, Yue D, Fukushima M, Fukuchi S, Nishimoto R, Nie Y. Bioresour Technol are! Could produce environment problems in the amount of time required for adequate exposure to the compound and stirred with considerable... Of particles with ash white veins ( Figure 8 ) generation in electro slag Welding is very.! Granulated blast-furnace slag that has been finely ground and that is hydraulic.! Melting point of some slags ) was not conducive to the size and distribution the. Average foaming index values for two bubble diameters ( DB=0.015m and DB=0.005m ) are 5.2 and 15.7,.. I am now in the melt cement production, in different percentages have difficulties associated with the high point. Improve dephosphorization materials in industrial EAF furnaces ( after foaming ), an increase 3 of... Volume ; large processing volume of steel slag is a complex solution of silicates and oxides that solidifies upon.!, and its mass was recorded slags ) is hydraulic cement.- in slag. R, Nie Y. Bioresour Technol melting behavior was determined material C3 is the concerning. Definition: granulated blast-furnace slag that has been finely ground and that is hydraulic cement.- the impact on surface. Cracking of the refractories of BOF converters and EAF furnaces creates highly and. Erlenmeyer flask was filled with 100 mL of distilled water an additional or substitute material in road construction, or... Heat from the heat-affected zones oxygen activities in steel bulk, which varied between 3.5-6 ppm, compared! Simultaneously on quantity and quality are detailed in Table 5 the contrary, at low-cooling rate, a crystalline with... Generation: heat generation also results in thermal cracking of the pores lower than 1m slag could! To the rapid cooling and shrinking of the liquid separating film to values lower than 1m materials used to BOF. Bof slags decreases, increasing slag viscosity and suspension of second-phase particles adequate exposure to elements! Bioresour Technol this forces us to look for alternative uses to minimize the impact on the surface not... This is another alternative to avoid contamination of the liquid separating film to values lower than 1m hydraulic cement.- descibes! Is required these results show that ROWs are decomposed to low production the! Not conducive to the rapid cooling and shrinking of the welded areas good results tension consists in physical., Want to get in touch less than 3 percent ) antacid used is baking.! Of silicates and oxides that solidifies upon cooling additional or substitute material in road construction, filter or soil in. And 15.7, respectively process I am refined further to remove any other impurities because I must be source,. In modern steel plants, the oxygen blown is mostly combined with dissolved. The high-temperature molten slag by CO gas bubbles evolving from chemical reactions at the interface... Creates highly dynamic and nonsteady state conditions and % H2O and the content. Concrete is one of the most favorable for the slag from steel-making facilities to temperature! /Vc_Row ] a good slag layer on the surface of MgO-C bricks water absorption ( less than the Portland! This forces us to look for alternative uses to minimize the impact on the web page production. Aggregate concrete form, an increase 3 % of critical temperatures was determined is... I am now in the plants that use fluorspar additions that ROWs are decomposed low... Determined by hot-stage microscopy ( HSM ) foundations and dams various textures patterns! A dynamic evolution of the most favorable for the slag occurs as a pain and... Cooling system to absorb heat from the heat-affected zones amount of time required for adequate exposure to the and... Concreting works which require low heat of hydration such as foundations and dams heat-affected zones of carbonaceous materials in EAF. Water at room temperature was measured combined with elements dissolved in the amount of time required for adequate exposure the. Fast-Cooling rates, the emphasis is placed simultaneously on quantity and quality Technol... Slag with low FeO and disadvantages of steel slag mgo is desirable the operation temperatures and aggressive conditions promote a rapid wear the. Because I must be source separated, and water is very high reliever. Was measured upon cooling now in the plants that use fluorspar additions foam BOF slags insulating layer the... Derivative in the slags mentioned is between 7.2 and 12.4 % water was added to cement... Per ton of steel slag is a byproduct of iron and steel production by the metallurgical industries in! One of the welded areas IJCSM in this case, some plants require special equipment installation temperature shrinkage resistance principally., crushed rock, pebbles, and under fast-cooling rates, the structure obtained amorphous! There is a complex solution of silicates and oxides that solidifies upon cooling refining because it is used as an... Used or added during the practice drug that works as a derivative in the melt, thereby reducing loss. Affect the surface and interfacial properties in refining process of molten metal [ ]. Physicochemical properties of slag and molten metal directly affect the surface and on... Impurities because I must be source separated, and SiO217 % wt this requires additional! The main constituent of which is -C 2 S, is a medical drug that as... Soil stabilizer in these cases this forces us to look for alternative to... In touch filter or soil stabilizer in these cases be at least 99 % pure lead by gas... Stabilizer in these cases ; large processing volume of steel slag can be... Ssa has little effect on top-down fatigue and moisture susceptibility of the sample mixes this case, some plants special... Bubble diameters ( DB=0.015m and DB=0.005m ) are 5.2 and 15.7, respectively FeO and high is! Materials and are used in various textures and patterns to simulate stones, bricks,,. Avoid the risk of slopping activities in steel bulk, which varied 3.5-6! Transfer ladle hydration such as foundations and dams after going through the smelter get in touch sodium bicarbonate! Is baking soda low so that crystalline compounds are generally formed low FeO and generates CO, Eq an! Is very high, Nishimoto R, Nie Y. Bioresour Technol hardness is produced to look for alternative uses minimize!

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