The Federal Ministry of Agriculture, Regions and Tourism has laid down the necessity of waste avoidance, recycling management and resource conservation. We at Breitenfeld Edelstahl AG contribute significantly to the issue of recycling management by processing metallic waste (scrap). The waste generated during steel production is to a large extent reintroduced into the production process through processing measures.
To name a few examples of our recycling management and resource conservation measures in Breitenfeld:
The smelting waste consists mainly of waste from the casting areas. This includes sands, casting ceramics, casting powder and dusts, as well as a metallic component which consists of scrap used for sealing in the casting area, other small scrap and casting waste of different sizes. In order to avoid the transport of the metallic part of the smelting waste to the landfill (costs landfill volume and legal fees occur), the smelting waste needs to be demetallized. This is carried out in the processing area for smelting waste with a converted screening machine. An overbelt magnet separates the metallic content and returns it to the steel production process. In 2019, 1,977 tons of scrap were separated from 8,818 tons of smelting waste. This means that about 22% of the smelting waste is scrap. The metal-free smelting waste is deposited on the landfill.
Electric arc furnace (EAF) slag:
Slag in the EAF is needed to separate elements detrimental to steel and to better transfer the energy into the melt (foamed slag). Slag occurs in the furnace vessel and deslagging stand which also leads to slag entering the slag trough. The separation of the steel slag that occurs due to different density and temperature is carried out on the slag preparation area. With a portable analysis device, the steel waste which is returned to the scrap management is assigned to a scrap group and allocated according to steel brand. In 2019, 2,417 tons of steel waste were separated from 27,571 tons of slag. This means that almost 9% of the slag is steel waste. The slag is deposited at the landfill in the interim storage compartment. From there, the slag = artificial rock as a substitute for gravel (resource conservation) is removed for the usage in special concretes in rock filling (filling material or support material in mining areas). For this, the slag needs to be crushed to a specific grain size. During this process, any metal that is still embedded in the slag is separated and returned to the scrap management system.
With this further use of the slag, expensive landfill volume can be saved and the steel production site secured.
The slag used in the production process in the ladle furnaces is granulated by rapid cooling and is then returned into the steel production process as EAF slag (recycling management).
Refractory waste, furnace vessel:
The refractory waste occurring when lining up the lower furnace vessel consists of fine material, brick fragments or bricks and metal contamination. The fine material can then be used as a slag optimizer (resource conservation/recycling management) in the steel production process. The bricks are bought back by the refractory material manufacturers and re-processed into refractory bricks (resource conservation/recycling management). A trial process has turned out to be very successful. The metallic portions could be separated very well, and also the separation of the fine materials and the larger parts showed positive results. Trial deliveries to refractory material manufacturers have already been made.
The basic rule is: Waste from a production process always occurs from raw materials that have been previously supplied to the process, and thus caused costs. Waste avoidance needs to be the top priority.
Separating the waste where it occurs is cheaper than processing the mixed waste at a later point.