Future Research and Developments on Reuse and Recycling of Steelmaking By-Products

Abstract

In the steel sector, sustainable management of by-products is a key challenge to preserve natural resources and achieve the zero waste goal. In this paper, the main trends of future research and development on reuse and recycling of by-products of the steel industry are presented in the form of a roadmap, which is the outcome of a dissemination project funded by the European Union based on the analysis of the most relevant and recent European projects concerning reuse and recycling of by-products from the steel production cycle. In particular, the developed roadmap highlights the most important topics of future research activities and challenges related to reuse and recycling of by-products from the existing or alternative steelmaking routes. A time horizon of 10 years has been considered, taking into account the European Commission targets to achieve carbon neutrality in a circular economy context. In addition, current technological trends derived from past and ongoing research projects are analysed. Research needs are based on the main categories of by-products and residual materials. Due to the different pathways to reduce CO2 emissions, each category is divided into subcategories considering both current and novel process routes targeting decarbonization of steel production. This work identifies the most urgent and demanding research directions for the coming years based on a survey targeting the steel companies, services providers of the steel industry and research organizations active in the field.

Towards the Circularity of the EU Steel Industry: Modern Technologies for the Recycling of the Dusts and Recovery of Resources

“…On the contrary, no major difficulties limit the use of BF slag (BFS in Figure 1) in Europe; out of the 20.7 Mt of BFS generated in the EU in 2018 (over 35% of the total in Germany), the 80%, 18%, and 2% were used for cement and concrete production, road construction, and others, respectively [14]. Regarding the overall steelmaking slags (16.3 Mt in the EU in 2018), being 52.3%, 34.9%, and 12.6% from BOF, EAF, and others, respectively, only the 72.4% was reused as concrete aggregates (70.6%), fertilizer (13.1%), recycled raw material for metallurgical processes (10.5%), additive in hydraulic engineering (4.5%), and road construction (1.3%) [15]. Therefore, around 5 Mt of slag is currently landfilled every year in the EU, reflecting a large waste of potential resources.…”

The Waelz Slag from Electric Arc Furnace Dust Processing: Characterization and Magnetic Separation Studies

“…The Waelz process also produces another solid product named the Waelz slag, which contains the main part of the residual elements of the treated EAFD. It is estimated that the processing of every ton of EAFD generates 600-800 kg of the Waelz slag [10,11]. It is mostly not recycled but landfilled or stored on-site, thereby causing environmental risks [12].…”

Solar Drying of Sludge from a Steel-Wire-Drawing Industry

“…On average, every tonne of steel that is produced generates approximately 200 kg of waste, in scrap metallurgy, or 400 kg in iron-ore-based steel [15]. Mill scale represents 2% and refractories 7% of the total amount of by-products [16].…”

“…The sludge results from equipment involved with the reduction of residual water and gas from different processes. Due to the advancement of the circular economy and environmental requirements, companies have sought to use these wastes in internal processes [16]. Within this context, this article presents a solar drying process for sludge from a wastewater treatment plant (WWTP).…”