Enhanced EAF steelmaking through continuous charging, scrap preheating and electromagnetic stirring (Consteel / Consteerrer)

Continuous charging of scrap combined with scrap preheating, i.e. the Consteel® process, is a proven EAF technology applied in more than 80 installations worldwide (2025). It was developed by Tenova and can be retrofitted to most existing top-charge EAF plants. A novel electromagnetic stirring system, i.e. the Consteerrer®, has also been developed by Tenova and ABB to improve the overall EAF performance (e.g. reduced energy consumption / process times, increased yield of metallic charge).

TECHNICAL DESCRIPTION

Consteel® process: The Consteel® process enables to continuously preheat and feeds metallic charge (e.g. scrap, pig iron, DRI) to an EAF using an inertial conveyor which transports the scrap from the charging section to the furnace, passing through an enclosed preheating tunnel in which the scrap is pre-heated using the process exhaust gases which are travelling in the opposite direction towards the exhaust gas extraction system. Typically, scrap can be preheated to temperatures ranging from 400 to 600°C. The preheated scrap is continuously fed into the EAF, where it is melted by immersion in the liquid steel helping to stabilise the electric arc by reducing flicker and increasing electrical efficiency.
With continuous charging, bucket charges are not used anymore; the conveyor feeds the scrap from the scrap yard directly into the EAF. The Consteel® process can be retrofitted to most existing conventional top-charge EAF plants. As of 2017, more than 50% of the operating units were provided as a retrofit of an existing top charge EAF. Nowadays, Consteel EAFs reach 350 tonnes heat size and productivity of 450 tonnes per hour and feature scrap conveyors up to 4 m wide.

Consteerrer® technology: This patented technology consists of an electromagnetic system applied to continuously charged EAFs, which stirs the liquid steel, significantly improving its thermal and chemical homogeneity, increasing the kinetics of the reactions developing in the liquid, and increasing the transfer of heat from the slag layer. The electromagnetic stirrer is located underneath the EAF lower shell, generating a stirring force that may be adjusted in both intensity and direction according to the current needs of the process. The Consteerrer® technology enables to significant increase in the melting rate as well as the physical and chemical homogenisation of the bath. This provides advantages such as reduced specific energy consumption and processing times. Compared to a conventional Consteel® furnace, a Consteerrer® EAF will be faster in the melting process with a reduced energy consumption and will produce superior quality steel through improved control and greater repeatability of operational practices.

DEGREE OF MATURITY
The Consteel® technology is fully commercially available and implemented across many steelmaking installations across the world (e.g. Acciaieria Arvedi in Cremona and Ori Martin S.p.A in Brescia, Italy).

The Consteerrer® technology has a technology readiness level well above 9. It is already operational and commercially proven in 8 installations worldwide. In Europe, this technology has been implemented at Acciaierie Arvedi (Italy) since 2020, leading to the achievement of production rates in excess of 410 tonnes/hour of liquid steel. This plant is currently considered the world’s most productive EAF.

CROSS-MEDIA EFFECTS
Continuous scrap charging requires an increase in the use of slag foaming agents throughout the process compared to batch charging EAFs. However, costs associated with the increased foaming agent use can be offset by the elimination of chemical heating, the energy recovery from furnace fumes and the possibility to use alternative materials (e.g., biochar, recycled plastics).

Basic information about the technique

Participant Companies