Table of Contents
What is the purpose 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.
Why slag is important in metallurgy?
Slag, Metallurgical. They play an important role in the physicochemical processes of metallurgical production: they remove undesirable impurities in metals and protect metals from the harmful effects of the gaseous medium in the furnace (that is, from oxidation and gas saturation).
What are the functions of slag in the production of steel?
In particular, slags are used to remove impurities such as sulphur, phosphorus and inclusions from the metal, and a large amount of research has been done in this area. Slags also insulate the metal thermally and form reactions with the atmosphere such as reoxidation and nitrogen pick-up.
Why is slag collected over iron?
Just below the middle of the furnace, the temperature is high enough to melt both the iron and the slag. They collect in layers at the bottom of the furnace; the less dense slag floats on the iron and protects it from oxidation.
How is slag created?
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 it important to remove the slag?
Removal of the slag is necessary for four reasons: ability to inspect the quality of the weld area; if a second layer or pass of welding is to be made on top of the first; to clean and clear the surface for coatings such as paint or oil.
Is steel slag used in road construction?
Such slag is a valuable raw material for preparation of macadam materials and mineral binders serving as a base for asphalt concrete mixtures and manufacturing of cement emulsions, which are widely used in road paving.
Where is slag found?
Is iron slag toxic?
When SSRS compares with ground granulated blast furnace slag (GGBFS) from iron making, steel slag contains toxic ingredients such as nickel, cadmium, chromium and strontium. These compounds could be harmful not only for environment but also for human health [9,10].
Should slag be removed?
When welded structures are hot-dip galvanized, the weld area cleanliness significantly affects the quality and appearance of the galvanized coating around the weld. Therefore, weld slag must be removed by grinding, abrasive blast cleaning, wire brush, flame-cleaning, or chipping.