What is slag in the steel making process?
Steel slag, a by-product of steel making, is produced during the separation of the molten steel from impurities in steel-making furnaces. The slag occurs as a molten liquid melt and is a complex solution of silicates and oxides that solidifies upon cooling.
Why is Dephosphorization important?
Dephosphorization of steels has become a very important metallurgical technique in steelmaking process to produce high quality steels. As the P content is controlled by the reactions in BOF, the double slag technique has generally been applied to obtain low P killed steels.
What is the main function of slag?
Slag floats on the surface of the molten metal, protecting it from oxidation by the atmosphere and keeping it clean. Slag forms a coarse aggregate used in certain concretes; it is used as a road material and ballast and as a source of available phosphate fertilizer.
What is slag carryover?
The steel is tapped into a ladle, which serves as the refining vessel to adjust the final steel composition and temperature before casting. Some steelmaking slag is inevitably tapped with the liquid steel. The mass of steelmaking slag tapped with the steel is termed ‘slag carry-over’.
Why slag is important in steel making?
The important roles slag plays during steelmaking are as given below. It acts as a sink for impurities during refining of steel. It controls oxidizing and reducing potential of the bath during refining through FeO content.
What is slag in forging?
Forge slag is the waste product of the various forging processes.
What is Dephosphorization process?
The dephosphorization processes (reduction in the phosphorus content) of pig iron consist in oxidizing the phosphorus and combining it with calcium and other components, which are injected into the hot metal deeply, resulting in compounds which are transferred to the slag and, thus, removed from the metal.
What is the meaning of Dephosphorization?
Elimination of phosphorus from steel, in basic steelmaking processes. Accomplished by forming a slag rich in lime.
What is secondary metallurgy?
Secondary metallurgy solutions from Primetals Technologies stands for fully integrated technology, mechanical engineering, automation and electrical engineering from a single source. This is the basis for maximum plant availability, short charge-cycle times, low consumption values and top-quality treated steel.
What is the chemical name of slag?
The primary components of iron and steel slag are limestone (CaO) and silica (SiO2). Other components of blast furnace slag include alumina (Alsub>2O3) and magnesium oxide (MgO), as well as a small amount of sulfur (S), while steelmaking slag contains iron oxide (FeO) and magnesium oxide (MgO).
Why slag is important in metallurgy?
Metallurgical slags play an important role in the extraction and refining of metals. They are formed when a flux material, added to or included in the charge, reacts with unwanted minerals during extraction or smelting, or with the products of the oxidation of unwanted solute elements during refining.
How is phosphorus removed from steel?
In integrated steel plants, phosphorus removal usually takes place during the oxygen steelmaking process (OSM) but in Japan a intermediate step for hot metal dephosphorization is commonly used. There are various types of OSM furnaces but the most widely used remains the top-blown Basic Oxygen Furnace (BOF).
How do you remove Sulphur from steel?
There are four stages where sulphur can be removed: in the blast furnace (BF), during hot metal (HM) pretreatment, in the converter and during the secondary metallurgy (SM) treatment. For sulphur removal a low oxygen activity and a basic slag are required.
What is the melting point of slag?
nglos324 – slag. When producing metals from ores by a furnace melting process (smelting) it is common to have some unwanted SiO2 in the ore. This material has a melting point of about 1780 C and is not easily removed from the metal system which will have a lower melting temperature.
What is VD in steel making?
Vacuum Degasser (VD) allows to degas and decarburize the melt and provides the best conditions for desulphurization and inclusions removal. During the VD treatment, the liquid steel ladle is placed in a vacuum tank that can be of stationary or movable design according to the specific layout needs.