Naghshejahan steel research institute isfahan science and technology town, 2. Pdf characterization of ladle furnace slag from carbon steel. The changes in the inclusions calculated using the kinetic model were in good agreement with those predicted by the phase stability diagram. In this work, a method to analyze spectral reflectance of ladle furnace slag samples to estimate their composition is proposed. The slag can also be used to create fibers used as an insulation material called slag wool. The objective of this research is to encapsulate the chloride in mswifa and to develop a utilizable construction material using mswifa, ground granulated blast furnace slag ggbfs, ladle furnace slag lfs, and gypsum.
Other sources of oxygen include slag remaining in the furnace or ladle from previous heats, oxygen dissolved in the metal, air. Recycling of ladle furnace slags sima aminorroaya1, hossein edris2, ali tohidi3, jafar parsi3, bahram zamani3 1. Ladle furnace slag lfs, a byproduct of the steel making process, was tested for its potential use as a supplementary cementing material. Molten steel in a ladle may be treated refined in a device called ladle furnace lf.
Slag formation during the steel refining process in a. Ladle furnace slag characterization through hyperspectral. Ladle refining furnace lrf hani tech metallurgical. The slag generated from a steelmaking cycle is later processed, and the final product after processing is referred to as basicoxygen furnace slag bof slag. The ladle is transported to the ladle furnace stand where it is placed under a cover equipped with three graphite electrodes connected to a threephase arc transformer.
Study of lf slag composition and its correlation with the desulphurisation. Today, the production of different grades of highquality steels without metallurgical processes like alloy handling, degassing, heating, stirring and decarburisation is unimaginable. Ladle furnace reducing slag is a common byproduct in steelmaking of carbon and low alloy steels. Fix ladle refining furnaces, electrotherm india limited. Tracking inclusions during ladle refining using a kinetic. Melting techniques type and size of melting furnaces, slag composition, condition, and quantity, temperature of melt, melting period. In order to make a complete characterization of ladle furnace slag lf slag, lfs, as nonhazardous industrial waste, and to solve its permanent disposal andor recovery, bearing in mind both the. Steel slag ladle slag raked slag clean up slag from furnace pits. Pdf a promising type of steel slag for applications is the ladle furnace lf slag, which. Different contents of ladle furnace slag filler, ranging from 60 to 120 kgm 3, and steel fibers, ranging from 0% to 0. As oxygen is blown into the furnace, the principal flux feo is generated. Sulfur and nitrogen in ladle slag carl allertz doctoral thesis. Basic 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. Ontario produces 80% of canadas 16 m tonnes of steel cannot make steel without making slag 1.
The first of them, s1, was a ground granulated blast furnace slag ggbs with mechanical processing. This work investigates the effect of slag composition in steelslag and steelinclusion reaction kinetics in siliconmanganese killed steels by using factsage. Secondary metallurgical slag secs is generated during production and refining of highquality steels by secondary metallurgical processes. 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. Mass transfer and slagmetal reaction in ladle refining a. Self compacting concrete mixtures with the use of ladle furnace slag as filler and steel fibers as reinforcement were produced and tested in the laboratory. After air cooling and weathering over several days, this material is completely ground into fine white particles. Desulphurization of steel at ladle furnace depends on. Synthetic slag modifies the composition of ladle slag. Effect of granulometry on cementitious properties of ladle furnace slag. Chemical composition of the ladle furnace slag has been. Slag, steel, ladle and nonmetallic inclusions equilibria in an aseaskf ladle furnace kamrooz riyahimalayeri doctoral thesis department of materials science and engineering school of industrial engineering and management kth royal institute of. The ladle bottom has a porous refractory plug, which is connected to the argon supply pipe at the ladle furnace stand.
Effect of ladle furnace slag composition in simn killed steel. As the chemical composition and free lime fcao content of each batch of slag are significantly. Ladle cars for each treatment position ladle furnaces lf the quality link between melting and casting being the inventor and market leader of the ladle furnace technology, primetals technologies always finds the best ladle furnaces are available as single or twin ladle furnace, depending on productivity demand and cycle time of. Control of gas bubbles and slag layer in a ladle furnace. The alkaliactivated aa slagbased materials are promising alternative. The different mixtures were tested in the fresh state. A method of making a steel with low carbon less than 0. The sulphide capacity of the slag was assumed constant during ladle treatment in the cfd calculation. Rapid air cooling method prevent expansion of the steel slag. These expressions have some constrains with respect to the slag composition and are only valid at one temperature, 1600 oc. Ladle furnace slag samples were prepared for eds analysis as follows. Ladle furnace slag lfs is a byproduct of a steel plant. Due to high cao concentrations the material can be used in the production process of cement, as a limestone replacement.
Concrete properties comparison when substituting a 25%. Behavior of self compacting concrete containing ladle. How to calculate a slag composition in a ladle using a massbalance approach consider the following additions to a ladle. The aim of applying synthetic slags is to create a fluid, sufficiently basic, and liquid slag with a low melting temperature, which contributes to an acceleration of the physical and chemical processes at the slag metal interface, thus influencing the efficiency of the secondary steelmaking. Surface area properties have shown that the lf slag is a mesoporous. No furnace slag was carried over into the ladle the recovery of al in the steel was 25%. Characterization of ladle furnace slag from carbon steel. A kinetic model to predict the compositions of metal, slag. 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. Ladle metallurgy is sometimes also called ladle refining or secondary steelmaking. In a previous paper, black spanish eaf was characterized and was found to be composed. The developed model was useful for optimizing the operation of a ladle furnace.
Use of ladle furnace slag and other industrial byproducts. This process produces slag with only small variations in composition and properties. After tapping of steel from a primary steelmaking furnace such as bof, eaf or eof, molten steel for high quality or specialty applications is subjected to further refining in a number of alternative processes collectively known as ladle metallurgy. On the other hand, s2 and s3 types were unprocessed ladle furnace slag lfs from two different steel mills. Rapidly air cooled ladle furnace slag produce hydrogarnet during the hydration. Synthetic slag for secondary steelmaking ispatguru. Sulfur and nitrogen in ladle slag semantic scholar. Physical system the ladle system simulated in this paper is shown in figure 2. Turkdogan equilibrium constant experimental data flow rate flux free energy furnace tapping gas bubbles gases given in fig fundamentals of steelmaking turkdogan haematite hot ductility hot metal hsla steels hydrogen inclusions increasing injection interdendritic liquid iron oxide fundamentals of steelmaking turkdogan ladle slag layer liquid. This method does not require sample preprocessing and is based on a regression algorithm that mathematically maps the spectral reflectance of the slag with its actual composition with errors lower than 10%. However, to date, there are no industrially consolidated techniques that allow us fast and insitu analysis of the chemical composition of the slag.
Ladle furnace slag is a byproduct of the steel industry, deriving from the second stage of the production process, which presents some cementitious properties. After the ladle treatment the ladle is transported to the casting station and the steel is cast. The goal was to find a suitable percentage share of ladle slag used as an admixture. Chemical, mineralogical, and morphological properties of. Effect of ladle furnace slag composition in simn killed. This order does not apply to the supply of processed electric arc furnace ladle slag to a consumer for land application at a premises for which the consumer. Optimisation of ferro alto, usage in steetrnaking apr95 hay jun. Kinetic model of steel refining in a ladle furnace.
Effect of ems on inclusion removal in ladle furnace for. Refining in the ladle furnace lasts between 40 minutes and 1 hour. Online slag composition analysis for electric arc furnaces. The slag floats on the surface of the molten metal thereby preventing oxidation of the metal. Except for heating ladle furnace is an excellent place to make desulfurization with slag, catreatment, and other alloying and trimming additions. Surface area properties have shown that the lf slag is a mesoporous material with. The process outline from converter to ladle furnace, vacuum treatment, and casting is presented in figure 1. Industrial arc furnaces range in size from small units of approximately one ton capacity used in foundries for producing cast iron products up to about 400. Electric arc furnace slag is generated when iron scrap is melted and re. Municipal solid waste incineration fly ash mswifa is a hazardous byproduct of waste incineration. The results of compressive strength tests show the possibility of replacement of a significant amount of cements with a specific secondary product. There are different sources bof vs eaf steelmaker does affect slag quality why is the csa interested in opss. Control of gas bubbles and slag layer in a ladle furnace by electromagnetic stirring. The molten steel obtains new heat energy by arc heating, which not only can supplement the alloy and adjust the composition during the refining of the ladle, but also can add slag to facilitate deep desulfurization and deoxidation of the molten steel.
This work investigates the effect of slag composition in steelslag and steel inclusion reaction kinetics in siliconmanganese killed steels by using factsage. Hydration properties of ladle furnace slag powder rapidly cooled by air. The potential of ladle slag and electric arc furnace slag. Stabilization and crystal characterization of electric arc furnace. Typical compositions of blast furnace slag, bof slag, and electric arc furnace slag mass% 80. Study of the suitability of different types of slag and. Control of slag and insoluble buildup in ladles, melting. An electric arc furnace eaf is a furnace that heats charged material by means of an electric arc. Study of lf slag composition and its correlation with the. Then the bath is refined in a vacuum chamber where it continues to be mixed by argon blown in at the bottom. 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. Vacuum refining influences not only the chemical composition of the metal, but also partly changes the composition of slag. This system is specially designed to remove slag with phosphorus to make the steel clean. This work investigates the effect of slag composition in steel slag and steelinclusion reaction kinetics in siliconmanganese killed steels by using factsage macros to simulate and predict inclusion composition and morphology changes during ladle treatment. 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. The chemical composition of ladle furnace slag samples was investigated by. Plant trials were conducted to illustrate the useful chemical composition of flux through assessing the effect of lf slag addition on some criteria such as ladle. A sensitivity analysis is also carried out to investigate the effect of different parameters, including sulfur content of steel, total oxygen, slag composition, and reoxidation of steel on the trajectory of composition of inclusions during the ladle process.
Significant influence for steel desulphurization has content of easily reducible oxides in slag. The research was dealing use of ladle slag and its impact on the physical and mechanical parameters of hardened cement composites. Secondary functions that can be included with a ladle furnace are. This paper examines the use of ladle furnace steelmaking slag lfs as a material for the construction of embankments in civil works. Amount % cao % mgo % al2o3 lime 700 100 dolomite 500 60 40 caaluminate 500 45 55 al 100% 340 assumptions. The resulting byproduct, ladle furnace slag, contains high concentrations of calcium oxide. The composition of furnace and ladle slag is often very complex. At slag raking, the slag will be pushed towards the slag rake side under the electromagnetic force, move the steel upwards on the stirrer side of the ladle and make the slag removal more efficient and thorough. Make the molten steel warm and heat preservation function.
Owing to our vast industry experience and expertise, we have been able to offer ladle refining furnaces. Chemical composition of the ladle furnace slag has been determined using energy dispersive spectrometry eds. Slag, steel, ladle and nonmetallic inclusions equilibria. The processed electric arc furnace ladle slag order 2014. Pretorius, baker refractories ii introduction to slag fundamentals a what is slag. Missouri university of science and technology scholars mine. Pdf kinetic model of steel refining in a ladle furnace. It reports the chemical, mineralogical, and geotechnical properties of two soils, two lfs, and various mixtures thereof, in addition to their volumetric stability. 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 operation executed at the ladle furnace is an essential part of the secondary metallurgy treatment, such as refining, adjustment of liquid steel temperature and chemical composition with the target to increase quality of steel. The chemical reactions occurring during the removal of impurities determine the chemical composition of the basicoxygen furnace slag 1, 3, 5.
Ladle furnace slag is produced through the addition of lime cao, and dolomitic limestone cao. The aim of the work presented in this contribution was to study the possibilities of eaf slag recycling into the refining remelting process in eaf and to recognize all possible positives and negatives of the recycling. One of the simplifications used in the previous work was that the oxygen potential. The slag balance now starts to shift and the slag becomes more liquid.
Tapping slag and molten metal in cupola furnace when sufficient liquid metal is collected in the reservoir, the slag door is opened and the slag floating on the surface of the molten metal is tapped and disposed off. Ladle furnace slag in construction journal of materials. Slag formers are either charged with the scrap or blown into the furnace. Ladle furnace slag in the construction of embankments.