Displaying items by tag: Steel slag

Czech Republic: A project by ArcelorMittal Ostrava substituting the primary raw materials for steelmaking with specially processed recycled slag has been ranked fourth in a government competition promoting the use of waste by-products as resources. The Ministry of Industry and Trade ran the competition that received 127 entries. Project manger Jitka Halamová attended the award ceremony on behalf of the steel producer.

“Since we've been using a special technology to sort the slag to end up a with higher iron content and a lower level of phosphorus, we have been able to reuse that slag in our operations in much higher amounts than before. Thanks to that, we are able to save iron ore, additives and fuel and, at the same time, we don’t accumulate large amounts of waste on our premises,” said Halamová.

The new technique mechanically processes the 0-8mm steel slag that contains 35 - 40% of iron. This has enabled ArcelorMittal Ostrava to increase the slag’s iron content to 54 - 57%, while keeping the phosphorus content low enough to reuse the enriched slag in the sintering process, replacing iron ore, additives and fuel in production. Using slag in this way increases the sustainability of the business’ operations and offers economic benefits. In 2016 ArcelorMittal Ostrava recycled on average 1900t/month of enriched slag and in the process saved a total of over US$0.87m.

Brazil: ArcelorMittal Tubarão and Usiminas have been nominated in the Steelie Awards for a steel slag rural road-building project. The steel makers have been put forward for the Excellence in sustainability category of the eight edition of the awards organised by the World Steel Association. The winners will be revealed at the annual dinner of the 2017 General Assembly of the association in Brussels, Belgium on 16 October 2017.

ArcelorMittal’s research and development department developed its Revsol and Revsol Plus products, which turn steel slag into a primary road, car park and storage yard coating, replacing the use of non-renewable sources in road building. The manufacturers say that the product also reduces the need for road maintenance.

Qatar: The Ministry of Municipality and Environment (MME), the British Transport Research Institute (TRL), Qatar Steel and Ashghal have been running a pilot project to use steel slag in the construction sector including to build roads. The test is part of the country’s infrastructure development in the lead up to the 2022 FIFA World Cup, according to the Gulf Times. Qatar Steel has accumulated large quantities of steel slag from its plant in Mesaieed. It produces over 350,000t/yr and has a stockpile of over 1.6Mt.

Slag road construction trials were conducted at a Qatar Steel site in 2016. The TRL has since recommended production of slag aggregate, certification of slag products by the authorities including MME and Ashghal, development of case studies and the inclusion in the next update to the Qatar construction specification.

China/Brazil: Harsco Corporation has signed two multi-year contracts for steel mill services in China and Brazil at a value of over US$100m.

Harsco’s Metals & Minerals division has been selected by Hebei Iron and Steel Group to take over an increased range of onsite mill services at its Tangshan Stainless Steel works, where Harsco already provides environmental services relating to the commercial sale of the mill’s slag co-products. With the new contract, Harsco now adds onsite slag handling, metal recovery and briquetting to its responsibilities. Tangshan Stainless produces premium-grade steels for automotive and consumer markets. The deal will include the use of Harsco’s steam box technology for steel slag processing.

In Brazil, Harsco has been selected by one of the country’s largest fully integrated steelmakers to extend Harsco’s services for onsite scrap handling, slag transport, metal recovery and melt shop support. Harsco has been providing support to the mill’s flat steel operations for more than three decades, and to its mini-mill since its inception in 2014.

“These contracts reflect our renewed ambitions to grow the Metals & Minerals business following two years of successful transformation. Our relationships in both contracts demonstrate our capacity to provide long-term value to customer operations in parallel with lasting benefit to the environment,” said Harsco president and chief executive officer Nicholas Grasberger.

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.