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Amid the destruction of the global environment by water and atmospheric pollution, deforestation, and desertification, developed countries are moving toward a recycling-oriented society as an effective measure to prevent environmental destruction.

Reuse and recycling of Coproducts

At Daido Steel, in fiscal 2019, coproducts emitted from the electric furnace steelmaking process included 277,000 tons per year of scrap steel (in-house) and 398,000 tons per year of steel slag (effective use: 311,000 tons, landfill: 87,000 tons, storage: 0 tons). Slag at the Company’s Chita Plant is utilized in roadbed materials (maintain social capital), and new applications are being developed to use it as an effective resource.

Reuse and recycling of by-products

Recycling of steel manufacturing slag

The slag resulting from steelmaking that had been used as a base coarse roadbed material for road construction was selected as a procurement good by enactment of the Green Purchasing Law in 2000.

By helping conserve natural resources and reduce greenhouse gases (GHG), slag is a valuable recyclable resource that contributes to the protection and preservation of the global environment. The Company’s Chita Plant produces and sells steelmaking slag products with proper quality management based on a third-party inspection in accordance with Guidelines Related to Management of Iron and Steel Slag Products, which was revised in January 2015. Steel slag turned into products at the Shibukawa Plant has been used as roadbed materials in public works projects in Gunma Prefecture. In 2013, however, levels of fluorine and hexavalent chromium that exceeded standards were detected in these materials. The Shibukawa Plant stopped producing and selling all steel slag in January 2014. This resulted in a decline in the amount of recycled steel slag and a sharp increase in landfill disposal. In the future, however, we aim to reduce landfill disposal by developing new recycling applications.

Recycling of steel manufacturing slag