Development of a suitable process for effective and efficient de-phosphorisation of liquid metal in induction furnace

Minj, R K and Singh, S D and Ghorai, S and Paswan, Dayanand and Bandyopadhyay, D (2013) Development of a suitable process for effective and efficient de-phosphorisation of liquid metal in induction furnace. In: Proceeding of the International Conference on Science and Technology of Ironmaking and Steelmaking, December 16-18, 2013, CSIR-NML Jamshedpur.

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Abstract

In India roughly 30 percent steel is produced through melting of sponge iron in induction furnace and subsequent alloy design is made suitable for structural steel. The huge shortage of steel scrap in India compels the small scale steel producers to use the sponge iron as a substitute of steel scrap. The low cost of investment and the easy availability of sponge iron attracted the small steel producer to use the DRI Induction furnace for the production of steel. The Induction furnace route has its own limitation for refining of liquid metal. The average phosphorus content in steel, produced through DRI + induction furnace route is reported to be in the range of 0.06 to 0.1 %. The required phosphorus content in any structural steel should be below 0.06%. The presence of phosphorus in engineering steel components beyond acceptable limit causes the cold shortness and highly unsuitable for engineering use.Conventional induction furnace offers a few difficulties, so far as refining of liquid metal is concerned. Slag being the sink of the impurities, presence of a slag layer is essential for the refining of liquid metal. Being insulator, it is difficult to melt slag and maintain its fluidity through induction heating. This results in very poor slag-metal mixing, hence poor reaction kinetics.In the light of the above, the induction furnace is generally used as a melting unit and no concerted effort has so far been reported towards the removal of phosphorus from liquid metal in an induction furnace. National Metallurgical Laboratory has developed a suitable process and fluxes for phosphorus removal in induction furnace. Different types of lime based flux with minor additives have been developed and successfully tested in laboratory scale furnace in both acid and basic linings. Minor lining modifications have been made to reduce the lining erosion of the furnace. The starting phosphorus content of the steel varies from 0.09 to .12 % and after treatment with flux developed at NML the phosphorus was reduced to 0.02 to 0.055%, which is well below the required BIS standard.In this paper, an attempt has been made to briefly present various aspects, including the fundamentals and outcome of several experimental investigations in relation to removal of phosphorus from steel.

Item Type:Conference or Workshop Item (Paper)
Official URL/DOI:http://eprints.nmlindia.org/7059
Uncontrolled Keywords:liquid metal,induction furnace, de-phosphorisation
Divisions:Material Science and Technology
ID Code:7059
Deposited By:Sahu A K
Deposited On:17 Nov 2014 13:12
Last Modified:12 Jan 2018 10:18
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