Displaying items by tag: Steel slag

Russia: NLMK Group has completed hot-testing of its new crushing and screening unit for the processing of steelmaking slag at its Lipetsk plant. The project will double the amount of scrap, or ‘metal inclusions‘, extracted from waste and returned to the production process. The new unit will process 2.4Mt/yr of slag, replacing an obsolete unit, which processed 1.7Mt/yr of slag. Metal extraction efficiency at the new unit will be as high as 95%, which will minimise the consumption of iron ore and scrap in pig iron and steelmaking operations through replacement with recoverables. The project had an investment of US$7.2m.

“The new unit will process the entire volume of our steelmaking slag, which is about 2.2Mt/yr, as well as allowing us to eliminate the need to process slag via third parties. The unit will also help us to recycle previously accumulated waste. This Strategy 2017 project is our next step towards increasing the role of recycling in bringing down steelmaking costs and reducing our environmental footprint,” said Sergei Filatov, the managing director of Novolipetsk.

Recovering production waste is one of NLMK’s priorities as part of its operational efficiency improvement efforts. NLMK Group is currently building a new briquetting plant at the Lipetsk plant. Briquettes will be manufactured from a mix of iron ore concentrate and blast furnace slag formed in the process of wet blast furnace gas cleaning. The plant will recycle more than 350,000t/yr of blast furnace waste.

Japan: Aichi Steel is set to increase production of AS Shot, a high strength abrasive shot made using steel slag. It plans to upgrade its Chita plant to increase output fivefold for the 2017 financial year, according to Japan Metal Daily. Shooting is applied for plating base materials and removing rust in a wide range of fields including bridges, automobiles and shipbuilding. Use of AS Shot reduces the amount of dust generated during blasting and enables treatment to have a long life and excellent machinability.

Japan: 240,000t of unapproved steel slag have been found buried at a US$66m residential development in Sodegaura, Chiba Prefecture, according to local press. The slag lacks the approval of the landowner contravening the Land Readjustment Act. The Land, Infrastructure, Transport and Tourism Ministry has started to investigate.

The Nippon Steel & Sumitomo Metal Corporation's Kimitsu works produced the slag before selling it to the developers. Research by the Mainichi newspaper suggests that the developers used the slag for ground improvement in 2012 before approval was obtained affecting the finances of the project.

Due to the swelling of slag when it absorbs water, if the slag-to-soil ratio surpasses 30%, users should to test in advance how much the mixture will expand. Steel slag is treated as industrial waste if it is not recyclable. Disposal of such slag costs US$170 – 340/t.

Sweden: Ovako has signed a contract with NCC to supply steel slag to be used as ballast in asphalt. As part of the contract, NCC will buy 50,000t/yr for the first three years and then 85,000t/yr. The road surface should be quieter, more durable and more sustainable, according to NCC-run tests in Borlänge.

Japan: According to Japan Metal Daily, the world's first space zero-gravity experiment using steel slag will start in Japan's current fiscal year. The experiment will try to suspend and melt steel slag in zero gravity to directly observe the interface between melt iron and slag. The interface between iron and slag, which is closely related to the steel refining efficiency, cannot be directly observed in earth experiments where crucibles are used. If successful, the basic research will provide highly accurate data on the interface, which are expected to advance high-purity steelmaking.

Korea: Korean researchers have developed a new cement-producing technology using reduced iron and steel slag.

On 11 March 2014, the Korea Environmental Industry & Technology Institute (KEITI) and the R&D Centre for Valuable Recycling announced that they have succeeded in producing rapid-hardening cement from metal slag reduced during the scrap metal recycling process, adding that the technology is suitable for commercialisation immediately.

Korean authorities bury 720,000t/yr of reduced metal slag in landfills. Using the new technology, Korea will be able to save US$3.79m in reduced slag disposal costs and produce US$254m of rapid-hardening cement. Korea has been relying on imported rapid-hardening cement for more than 80% of its domestic use.

The new technology is also expected to result in a 0.5Mt/yr reduction in CO₂ emissions, as it doesn't require the high-temperature melting of slag that is used in the current rapid-hardening cement manufacturing process. The two organisations added that the world could be supplied with US$6bn of cement if the technology was applied to the 17Mt/yr of reduced metal slag produced globally.

China: The total amount of steel slag generated in China was about 100Mt in 2014. At present, around 1Bnt of steel slag has accumulated in the country, but only 10% has been utilised for new purposes.