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09 May 2022

Dolomite High Purity in Steel, Paint and construction industry


A major use of Dolomite is in steelmaking. In steelmaking Dolomite is used both as a fluxing material and also as a refractory material For use in steelmaking, the SiO2 (because of its acidic nature) content in the dolomite is to be very low, preferably less than 1.5%. When it is used as a fluxing material, it is used in calcined form

As a fluxing material, it has a dual role. In its first role it is a source of some lime (CaO) and thus reduces the consumption of calcined lime

But the second role of Calcined Dolomite is the more important role. In this role it is used to protect the dolomite / magnesia-carbon lining of the steelmaking vessel This is done by making a steelmaking slag which is supersaturated in MgO at the temperature of steelmaking


Uses of Dolomite


These days slag splashing technology is being used extensively for the enhancement of the lining life of the AOD / BOF (basic oxygen furnace) vessel.

In this technology, calcined Dolomite is added to the retained liquid slag which is to be splashed on the BOF vessel. This is done to enhance the viscosity of the slag so that it can have better sticking / coating properties on lining bricks and also to enhance the refractoriness of the slag.

When dolomite is used as refractory material, then it is used in the form of sintered Dolomite. Sintered dolomite is used in steel making for the production of tar dolomite bricks, pitch impregnated Dolomite bricks or resin bonded dolomite bricks for the lining of BOF vessel, AOD (argon oxygen decarburization) vessel, and to a lesser extent electric arc furnace

These bricks are also used for the lining of the steel ladles.Dolomite based monolithic refractories such as guniting mixes are also used for the maintenance of the refractories of the steelmaking furnaces.

Guniting is normally done in those areas of refractory lining where there is high wear.

MISCELLANEOUS

These refractories are also used to form the hearth and banks in EAF, and to maintain them on a regular basis.

The maintenance of these areas is often carried out using a high iron, sintered dolomite which is applied on a frequent basis between heats using a spinning machine.

The machine is lowered into the furnace and applies several tons of fettling material in a couple of minutes between the heats. This fast, low cost solution is used particularly in those parts of the furnace where there is fast wear of refractories.