International projects
Upscaling of the two-step dust recycling process for Electric Arc Furnace Dust
Researchers (18)
Organisations (1)
Abstract
Steel mills are keeping an eye on technologies to treat their own dust in the most effective way.
This project establishes a regional recycling solution running economically with 12,000-13,000 to of dust per year, allowing “zero waste”, multi metal recycling. The two-step-dust recycling (2sDR) consists of a clinkering and a subsequent reduction step to extract zinc oxide and an iron alloy. The resulting slag can be used as construction material.
The solution (technology)
Zinc is mainly used for the galvanization of steel products to protect them against corrosion. After the lifetime of these products (e.g. car bodies or construction elements) they return to the steel mill as scrap, if recycled. The Electric Arc Furnace (EAF) is the common recycling facility for this purpose and uses up to 100% scrap. Within this process, roughly 20 kg of zinc containing dust is produced per ton of steel, ending up in 1.3 mio tons of so called EAF dust per year in Europe. At present, only about half of this amount is treated in huge centralized facilities, recovering only zinc. The novel ‘2sDR’ (two-step dust recycling) process represents the first zero-waste technology for zinc recycling and offers a flexible, environmental friendly and effective solution for steel mills to operate their own recycling process avoiding transport or disposal costs. The process consists of two steps, using two different metallurgical technologies: The material is clinkered in a short rotary kiln to remove harmful elements and then reduced in an Electric Arc Furnace. Zinc is extracted via the off gas as Oxide and can be sold, iron occurs in form of an alloy that is reused in iron and steel industry. The residual slag can be used for construction purposes. During the project duration, this process will be up scaled to semi-industrial size, technological and financial viability will be proven. Based on the outcome of this project, the technology is brought to market and the first recycling plant using the proposed ‘2sDR’technology shall be erected in Austria.
