Inline elemental characterisation of scrap charging for improved EAF charging control and internal scrap recycling (IPRO) : final report

The overall objective of this project is to develop an improved guidance of scrap charging operation for electrical arc furnace (EAF, both for carbon and stainless steel production) in order to stabilise process conditions and optimise internal scrap recycling. The focus of the project IPRO is the characterisation and identification of scrap pieces on conveyors in a mass flow for improved scrap use. The research is focused on charging of an EAF in the case of a continuous charging as applied in a Consteel® configuration - not by using already filled baskets - and in factory recycling and on sorting applications for scrapyards. Steel scrap transported on conveyor lines is characterised in-line with compact tailored laser analysers, monitoring the content of key elements in real time. In particular, systems were developed and set up for: monitoring of Si (and also Ni and Mo) in a continuous low-alloy scrap charging system with the objective to improve Consteel® EAF charging procedure control for process stabilisation, monitoring of Mo in high-alloy steel internal scrap for stainless steel production with the objective to improve internal scrap recycling. The systems were tested successfully in extensive field campaigns in steel production and their measurement results evaluated. The classification of internal scrap was achieved with a high degree of correctness. From the inline measurements of scrap composition, the elemental mass accumulated in the EAF was derived and factors influencing the calculation were studied.