All units carry out an automated waste inventory, with weight recording via SAP and communication passed on to the SGR (Waste Management System), the latter used at the Presidente Vargas Steelworks. The information is consolidated monthly in the waste inventory, which is passed on annually to the competent environmental agencies.
Waste Management
Possible destinations given to waste, equipment and obsolete materials to reduce the volume of waste destined for landfills:
In 2022, the total volume of waste generated by CSN’s businesses was 3% higher than in 2021 – excluding mining waste, this result is due to the start of the demolition and renovation of Battery 3# of the coke oven at the UPV. Most of the waste generated (98.4%) is classified as non-hazardous. Of these, 93% were destined for reuse, reprocessing or sold as an input for other production chains and only 7% are destined for duly licensed industrial landfills, incineration and effluent treatment.
Innovation project seeks solutions for disposal and use of steelmaking slag
The steel slag beneficiation process consists of the magnetic recovery of metallics, which return to the steelmaking process. The challenge is to study solutions available on the market for the disposal and use of the non-metallic fraction, known as steel aggregate. Currently, we work on the following fronts:
Donation to city halls
Commercialization as an aggregate for paving roads
Comercialização de escórias tipo C
Return of scrap metal for the electric furnace process in the steel industry
We continue to look for new ways to use them, which are still under evaluation, such as:
Rail ballast test
Studies for the use of slag for making concrete materials
Wet Mining Plant – a plant that benefits type C slag, recovering scrap and generating fine final aggregate for commercialization in the agroindustry as a soil amendment
Commercialization as an aggregate for paving roads
Part of the material is temporarily stored in a yard outside the Presidente Vargas Steelworks, called Slag Processing Yard. The product basically consists of calcium, magnesium and aluminum silicate, present in natural aggregates. Additionally, CSN Inova, together with the steelmaking, engineering, R&D and cement areas, continues to seek partnerships with Brazilian and foreign institutions, considering both existing options and new solutions to give the most appropriate destination to the steel aggregate.