Jan 17, 2010 the oxygen exists in the slag as iron oxide fe0, fluxes, mgo and cao which are the main constituents of the refractory lining. In steelmaking process, close control of slag evolution is as important as control of steel composition. Upon completion of the heating cycle, the electrodes are withdrawn from the furnace and the lid is raised. To test the reliability of an available computational thermodynamic computer program, the first sub project was done. The use of ls as a binding material in civil engineering is a potential solution. The preferred recycled lmf slag material generally comprises of 35% to about 65% cao. This type of slag has good physical properties, high inclusion absorptivity, and high sulfide capacity. Ladle furnace reducing slag is a common byproduct in steelmaking of carbon and low alloy steels. The slag composition is designed for different grades of steel being produced with the majority requiring desulphurization. A foaming slag will rise and cover the electric arcs, thus permitting the use of a high tap setting without increasing the thermal load on the furnace walls. The hot metalslag interface during desulphurisation. A ladle furnace provides for the exact adjustment of the chemical composition and temperature of the liquid steel. Ladle furnace slag characterization through hyperspectral. The composition of furnace and ladle slags is often very complex.
It reports the chemical, mineralogical, and geotechnical properties of two soils, two lfs, and various mixtures thereof, in addition to their volumetric stability. Lrf is use to desulphurize steel, remove other impurities and hold the molten steel for casting operations. Cao, sio 2, al 2 o 3, mgo, feo, mno, cr 2 o 3, p 2 o 5, tio 2, k 2 o and na 2 o. In this work, the optical emissions from the arc have been measured in an industrial ladle furnace and used for slag composition analysis. The influence of a curing regime on the geotechnical. A promising type of steel slag for applications is the ladle furnace lf slag. This type of slag generally has a rough surface texture, with a surface pore diameter of 0. Basic white slag is a coproduct of steelmaking, and is typically produced either through the blast furnace oxygen converter route or the electric arc furnace ladle furnace route. Additionally due to changes in scrap melting, the timing of the carbon injection is hard to define accurately without information of scrap melting and slag formation. Use of refining slag during the refining process of the lf furnace, the ladle is injected with a mixed slag prepared with a special ratio. Ladle furnace lf slag can be used as a replacement to synthetic fluxes owing to its chemical and mineralogical compositions.
Significant influence for steel desulphurization has content of easily reducible oxides in slag. The steelmaking process creates an industrial byproduct termed as slag. Ladle slag contains a high content of lime contributing to quick selfhardening, which. The slags that form in electric furnace melting result from complex reactions between silica adhering sand on casting returns or dirt, iron oxide from steel scrap, other oxidation byproducts from melting, and reactions with refractory linings. Electrical heating of steel in a ladle arc furnace to control the temperature and. Pdf characterization of ladle furnace slag from carbon steel. Recycling ladle furnace slag as flux in steelmaking.
In most steel smelting enterprises, lf furnace is the main refining furnace. The dephosphorization slag composition was then further improved by induction furnace dephosphorization. This work investigates the effect of slag composition in steel slag and steelinclusion reaction kinetics in siliconmanganese killed steels by using factsage. Online slag composition analysis for electric arc furnaces. Trunnion housings effectively guard the antifriction bearings to guard against foundry dust, slag, and shot sparks. Pdf a promising type of steel slag for applications is the ladle furnace lf slag, which. Slag a is an electric arc furnace type slag, while slag r is a ladle furnace basic slag produced in the secondary stage of refining, when the steel is desulfurized.
During the transportation process, high temperature molten steel and molten slag around 1680. Killed steel process to reduce lime consumption, improve. Control of slag and insoluble buildup in melting furnaces. A study on molten steelslagrefractory reactions during. Ladle furnace slag is a byproduct of the steel industry, deriving from the second stage of the production process, which presents some cementitious properties. The lf slag is a byproduct from further refining molten steel after coming out of a basic oxygen furnace bof or an electric arc furnace eaf. The composition of al killed steel ladle furnace slag has beneficial properties for the sikilled steel process.
A process of refining steel in a ladle using solid granules or briquettes made from recycled lmf slag and raw materials to make a desulfurizing addition, a slag conditioner or synthetic refining slag is described. As the chemical composition and free lime fcao content of each batch of slag are significantly different, it is difficult to use the. Refining slag for the lf refining furnaces rongsheng kiln. The influence, reason and measure for slag buildingup of. Chemical composition of ladle furnace reducing slag. Ladles are often used in foundries and range in size from small hand carried vessels that resemble a kitchen ladle and hold 20 kilograms 44 lb to large steelmill ladles that hold up to 300 tonnes 330 tons. The ladle furnace consists of a refractory roof, a heating system, and, when. The lf stand is also equipped with an addition hopper mounted on the cover and a lance for injection of desulfurizing agents. Advances in molten slags, fluxes, and salts wiley online. The composition of furnace and ladle slag is often very complex. It can be melted into liquid slag under the heating treatment of electric arc.
The carrying out of metallurgical reactions in the ladle is a common practice in practically all steelmaking shops, because it is costefficient to operate the primary furnace as a highspeed melter and to adjust the final chemical composition and temperature of the steel after tapping. Different positions of the porous plug have been studied. Many nonferrous foundries also use ceramic crucibles for transporting and pouring molten metal and will. Control of gas bubbles and slag layer in a ladle furnace by electromagnetic stirring. The slags that the slags that form in electric furnace melting result from complex reactions between silica adhering sand and dirt. Ladle slag contains a high content of lime contributing to quick selfhardening, which results in a higher loadbearing capacity and a lower dust generation on rural roads and surrounding areas. These competing requirements must be considered when designing a slag practice. The chemical composition of ladle furnace slag samples was investigated by. There, new slag is added and a roof containing three graphite electrodes is lowered onto the ladle. In a preceding work 1, a kinetic model was developed to simulate steelrefractory. Some of the ladle metallurgy processes are shown in fig 1. Characterization of ladle furnace slag from carbon steel. Valorization of lf slag helps in sustainable steelmaking and also reduces steel production cost.
Refining slag for the lf refining furnaces rongsheng. Fundamentals of eaf and ladle slags and ladle refining. One experimental trial was made to simulate ladle steel slag and steelinclusion reactions using an induction furnace to simulate deoxidation and slag addition. The more of this slag coming into the ladle furnace, the greater is thus the risk of lining wear. Ladle slag impact of the main factors are refractory material, converter slag composition, ladle insulation, steel smelting, ladle turnover rate, ladle maintenance and insulation methods. Environmental considerations and technical benefits have directed research towards reducing cement clinker content in concrete, and one of the best ways to do this is to replace cement with supplementary cementitious materials.
The potential of ladle slag and electric arc furnace slag use in. The slag can also be used to create fibers used as an insulation material called slag wool. Us5397379a process and additive for the ladle refining. Hot metal chemistry is strongly influenced by the slag composition. Sep 16, 2019 ladle furnace lf slag can be used as a replacement to synthetic fluxes owing to its chemical and mineralogical compositions. Laboratory evaluation of ladle furnace slag in unbound. Ladle furnace slag lfs is a byproduct of a steel plant. Industrial ladle furnace slag composition analysis with. The inner face of the ladle is built from specialized refractory bricks. Slag, steel, ladle and nonmetallic inclusions equilibria in. Ladle furnace slag in construction journal of materials in civil. A promising type of steel slag for applications is the ladle furnace lf slag, which is also known as the basic slag, the reducing slag, the white slag, and the secondary refining slag. Due to these differences in production, the content of elements varies.
This process is used to reduce impurities and adjust the chemical composition of the molten steel. First, the ladle refractory is used to transport high temperature molten steel. Republic, youngstown contributor names palmer, alfred t. Constructional details of a typical ladle 8 the ladle structure is multilayered because of the fact that a ladle should be strong and heat insulated. Eaf slag is a nonmetallic byproduct that consists mainly of silicates and oxides formed during the process of refining the molten steel. Molten steel is tapped from the electric arc furnace into a ladle, which is moved to the lrf station. The potential of ladle slag and electric arc furnace slag use.
Treatments and recycling of metallurgical slags intechopen. Also, certain metallurgical reactions, for reasons of equipment design and. Different mixtures of selected precursors were prepared in the slag a slag r ratios 10, 31, 11, and 01 and further activated with potassium silicate using an activator to slag ratio of 1. Ladle furnace slag lfs is produced at the final stages of the steelmaking process in ladle refining furnaces. The main components of refining slag are caal2o4, al2o3, sio2, caf2, mgo, etc. Ladle furnace slag in the construction of embankments. Slag foaming foaming slag is used to increase the thermal efficiency of the furnace during the refining period, when the side walls are fully exposed to the arc radiation. This book contains the proceedings of the 10th international conference on molten slags, fluxes, and salts. The slag must be fluid under all blast furnace operating conditions. Furthermore, sms siemag will deliver the additives supply system and a gas.
Research article characterization of ladle furnace slag. Open ladles are typically furnished with a heat shield fixed to the underside of the bail to aid in deflecting heat away from the crane hook eye and hoist hook. Molten slag running from an eastern blast furnace into a cinder ladle. Regardless of the chemical refining requirements of slag, it is advantageous for the ladle slag to become as fluid as possible immediately upon trapping the metal from the furnace into the ladle 3. Ladle refining furnace mechanical engineering concepts and. In metallurgy, a ladle is a vessel used to transport and pour out molten metals. The granulated slag must meet cement industry specifications so it can be sold as a byproduct. A promising type of steel slag for applications is the ladle furnace lf slag, which is also. The chemical composition of ladle furnace slag samples was investigated by means of a several different analytical methods.
Composition and compressive strength of ladle slag fineshydrated. The simulated changes in inclusion chemical composition and phases, as well as total oxygen and dissolved aluminum in steel were compared. It is also known that this material has cementitious properties and can be used as a precursor in alkaline activation processes. So as to achieve the purpose of refining steel liquid, thermal insulation and so on. The use of the lf slag in further applications requires. Mpt international 12017 feb by mpt metallurgy plant. Use of ladle furnace slag containing heavy metals as a. Apr 23, 2014 these are i rinsing or stirring, ii ladle furnace, iii ladle injection iv ladle refining, v degassing processes, vi aod process, and vii casob composition adjustment by sealed argon bubbling with oxygen blowing process. Due to their mineral composition these industrial byproducts should be recycled and reused, not only for the purpose of reducing waste in the. Control of gas bubbles and slag layer in a ladle furnace by. As the slag is channeled out of the furnace, water is poured over it. Us5397379a process and additive for the ladle refining of.
The slags that form in electric furnace melting result from complex reactions between silica adhering sand and dirt from casting returns, oxides from scrap, other oxidation byproducts from melting and reactions with refractory linings. High calcium fly ash, ladle furnace slag, and limestone filler were investigated as supplementary cementitious materials in cement pastes, and binary mixtures were. The invention provides a method for converter steelmaking by lf ladle furnace refining furnace reducing slag. The potential of ladle slag and electric arc furnace slag. The utilization of slag in civil infrastructure construction, 2016. Control of slag and insoluble buildup in ladles, melting and. Effect of high calcium fly ash, ladle furnace slag, and. Evaluating slagmetal deoxidation equilibrium in secondary.
These metal ions are combined into caocaf2 group, caoal2o3 group, and caoal2o3sio2 group. An extensive suite of engineering and geotechnical tests was undertaken on lfs aggregates to evaluate its potential to use as a road construction material. Also, certain metallurgical reactions, for reasons of equipment design and operation, are. Effect of ladle furnace slag composition in simn killed. Slag, steel, ladle and nonmetallic inclusions equilibria. The composition of steel slag varies depending on the furnace type, composition of charges, and grades of produced steel. Cn103031401b method for converter steelmaking by lf. The lrfs acts as a buffer between the steel making furnace and the continuous caster, reducing casting costs and allowing greater flexibility in steel making operations.
Raw eaf slag often appears as grey or black colored lumps, depending on its ferrous oxide content. May 07, 2018 because ladle slag is a premelted flux, when it is recycled in the steelmaking process, it is easy to be remelted. After air cooling and weathering over several days, this material is completely ground into fine. This work investigates the effect of slag composition in steelslag and steelinclusion reaction kinetics in siliconmanganese killed steels by using factsage macros to simulate and predict inclusion composition and morphology changes during ladle treatment. The refractory material may be eroded by the molten steel and slag as well as corroded through chemical reactions with the slag and molten steel and the deoxidation products. Ladle steel slag in activated systems for construction use. The plasma heated ladle furnace for secondary metallurgical. Slag is the glasslike byproduct left over after a desired metal has been separated i. Ladle refining furnace water cooled ladle furnace roof. In spite of beneficial composition, valorization of lf slag is difficult due to its disintegration phenomenon.
Minerals free fulltext ladle steel slag in activated. This article focuses on caf 2 and mgo, since the caf 2 is a common additive material in the ladle treatment and high mgo content means that the ladle refractory lining is dissolving into the slag. The refractories can change the ladle slag glaze compositions and subsequently react with molten steel. In a steel plant, a ladle furnace lf is used to maintain the temperature of liquid steel during processing after tapping from eaf or to change the alloy composition.
The resulting composite material is the refined slag. Combined with converter semisteel component of chengde steel plant, the main components of 100t ladle dephosphorization slag were calculated to propose the initial ratio of dephosphorization slag composition. Surface area properties have shown that the lf slag is a mesoporous. The comprehensive utilization of steel slag in agricultural. Fumes formed during the operation are extracted through the cover.
The ladle is used for the first purpose when there is a delay later in the steelmaking process. Thereafter, the entire heating system is swung away sideways so that the ladle can be removed by crane. Surface area properties have shown that the lf slag is a mesoporous material with relatively. The potential use of lfs as a basesubbase material requires a thorough knowledge of its engineering properties. The production route will consist of an induction furnace, a ladle furnace with plasma heating, a detemtype vacuum plant and the segment caster, intecos latest development in the field of casting. Control of slag and insoluble buildup in ladles, melting. On the other hand, the study conducted by with surface application of steel slag, blast furnace slag, ladle furnace slag, and stainless steel slag at the installation of the notillage system presented that the ladle furnace slag, stainless steel slag, and steel slag had similar efficiency to the lime in the neutralization of soil acidity at 24. Effect of ladle furnace slag composition in simn killed steel. Ii introduction to slag fundamentals a what is slag.
It was concluded that limes, an interface for thermocalc, is a useful tool for slag steel equilibrium calculations. Materials free fulltext the potential of ladle slag and electric. In terms of refining steel slag ladle or white slag, it is estimated that for each ton of steel, between 20 and 30 kg of slag is produced. Steel is an inherently neverending product, in terms of recycling and reuse. Surface area properties have shown that the lf slag is a mesoporous material with. Aug 08, 20 this paper examines the use of ladle furnace steelmaking slag lfs as a material for the construction of embankments in civil works. Physical system the ladle system simulated in this paper is shown in figure 2. The chemical composition of ladle furnace slag samples was investigated by means. In this report the effects of revolution speed, temperature and steel composition on the.
A way to reduce environmental impact of ladle furnace slag. Feb 25, 2020 the disposal of ladle furnace slag ladle slag, ls containing traces of heavy metals produced during steelmaking has become an environmental issue. The alkaliactivated aa slagbased materials are promising alternative. Ladle furnace slag lfs is a solid waste byproduct from the secondary stage of steel making process in ladle refining furnace. Wo2015114545a1 use of ladle furnace slag from alkilled steel in.
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