Title

RADEX DPP Purging in Electric Arc Furnaces – A Winning System

RADEX DPP Purging in Electric Arc Furnaces – A Winning System

Authorship

VACEK, DI. HELMUT

VACEK, DI. HELMUT

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DOI

10.5151/2594-5300-24Aciaria-403-426

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Abstract

The improvement of the metallurgical reactions in the electric arc furnace, the better homogenisation and easier deslagging with the assistance of inductive stirring has been known since 1933, when Asea installed its first pilot coil between the refractory and the steel bottom of the furnace shell at the Surahammar Steel Mill in Sweden. Due to the problems of high winding temperatures it was necessary to construct the furnace shell of non magnetic, austenitic steel and to place the stirrer coil under the furnace bottom. This solution was relatively expensive and sometimes the additional installations themselves at existing furnaces are impossible without considerable changes. Taking advantage of the long experiences in other processes like oxygen converter bubbling, AOD-blowing and ladle stirring, RADEX Austria together with several electric arc steel makers has developed an alternative system by injecting in various gases via porous plugs through the hearth of the electric arc furnace with the aim to improve bath mixing and slag-metal reactions during the melting and refining processes. After several trials with porous plugs in the sidewall of electric arc furnaces it was quite clear that only an application directly in the hearth would lead to optimal stirring efficiency. In 1984 the first outstanding breakthrough was achieved in co-operation with Ferriere Nord, Italy. Three plugs were installed in the hearth and argon was fed directly into the steel bath. Beside many metallurgical benefits there was also an energy saving of an average 27 kWh/ton steel. RADEX could optimize the porous plug in respect of service life and stirring efficiency. Encouraged by these results, RADEX promoted the technology and now more than 80 steel plants all over the world operate the system successfully.

The improvement of the metallurgical reactions in the electric arc furnace, the better homogenisation and easier deslagging with the assistance of inductive stirring has been known since 1933, when Asea installed its first pilot coil between the refractory and the steel bottom of the furnace shell at the Surahammar Steel Mill in Sweden. Due to the problems of high winding temperatures it was necessary to construct the furnace shell of non magnetic, austenitic steel and to place the stirrer coil under the furnace bottom. This solution was relatively expensive and sometimes the additional installations themselves at existing furnaces are impossible without considerable changes. Taking advantage of the long experiences in other processes like oxygen converter bubbling, AOD-blowing and ladle stirring, RADEX Austria together with several electric arc steel makers has developed an alternative system by injecting in various gases via porous plugs through the hearth of the electric arc furnace with the aim to improve bath mixing and slag-metal reactions during the melting and refining processes. After several trials with porous plugs in the sidewall of electric arc furnaces it was quite clear that only an application directly in the hearth would lead to optimal stirring efficiency. In 1984 the first outstanding breakthrough was achieved in co-operation with Ferriere Nord, Italy. Three plugs were installed in the hearth and argon was fed directly into the steel bath. Beside many metallurgical benefits there was also an energy saving of an average 27 kWh/ton steel. RADEX could optimize the porous plug in respect of service life and stirring efficiency. Encouraged by these results, RADEX promoted the technology and now more than 80 steel plants all over the world operate the system successfully.