Foaming of the Slag and Recycling of Stainless Steel Dusts by Injection Into the Electric Arc Furnace for Stainless Steels
Final Report
Description:... This final report presents the synthesis of the performed work concerning the slag foaming and the recycling of the dust generated by stainless steelshop by pneumatic injection into a stainless steelmaking EAF. This work was performed by Ugine-Savoie Imphy at Ugine (USI) (coordinator), Krupp Edelstahlprofile (KEP), FEhS and IRSID. The pneumatic injection conditions of dust alone, co-injected with carbon and/or with FeSi at KEP or blended with coke at USI, were optimised to allow a stable process, in particular for the slag foaming implementation at USI. The dust recycling by co-injection with carbon and/or FeSi, as reducing agents, and/or by dust and carbon blend injection were carried out at KEP and at USI. That allowed reaching a recovery ratio of Cr, Mn, Ni and Fe respectively ot 81 %, 38 %, 97 % and 93 %. In addition, this practice leads to a decrease of the chrome oxidation in the slag by at least 20 %. This zinc content in the new dust increases significantly depending on the zinc content in the recycled dust. The implementation of slag foaming by dust and carbon blend injection allows increasing the electric power efficiency by at least 20 % and increasing the arc voltage during the flat bath period. This slag foaming process contributes to decrease the electricity consumption and the power-on-time in addition to the benefit due to the dust recycling. The dust injection in the EAF, with or without slag foaming, does not modify the slag characteristics.
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