Displaying items by tag: research

UK: A team of researchers from six UK universities has filed a patent for a clinkerless cement product called Cambridge Electric Cement. Local press has reported that the project, called UK Fires, saw researchers successfully produce the cement using renewable power from recycled cement powder and ground granulated blast furnace slag (GGBFS). Following its successes, UK Fires has obtained a further Euro2m in funding from the UK Engineering and Physical Sciences Research Council (EPSRC) to continue its work into the range of concrete wastes suitable for use in Cambridge Electric Cement production.

US: The Slag Cement Association (SCA) has announced the recipients of its 2021 Slag Cement in Sustainable Concrete Awards program. Thirteen construction projects were chosen to showcase the broad applications of slag cement and its impact on creating more durable and sustainable concrete. The infrastructure winners included projects with slag cement supplied by companies including Argos USA, Cemex, Lehigh Hanson, Ozinga, Skyway and St Mary’s Cement. These projects included work on roads, bridges, residential construction, a concert venue, a sport stadium, airports, a theme park and a hydroelectric dam. Two research projects on slag cement from Cleveland State University and Florida State University were also recognised.

Japan: JFE Steel and Innoqua, a startup linked to the University of Tokyo, are working on using slag as an artificial bed for coral reef restoration. JFE Steel has recently installed a 1m fish tank in the lobby of its Tokyo-based headquarters as part of a feasibility test for the biodiversity initiative, according to the Nikkei newspaper. The companies are testing Marine Block, a product made from slag that is processed using a proprietary technique to allow coral to attach to it easily. The initiative will examine which species of corals are most likely to attach to the Marine Block, the ideal growing conditions and then move on to larger-scale coral breeding.

The Japanese steel industry produces over 35Mt/yr of slag. The majority of it is used in infrastructure projects. JFE Steel hopes to use about 10% of the slag it produces in 2030 in port and marine applications.

Vietnam: The government has encouraged cement producers to increase their uptake of waste products, including slag, in cement production. The Viet Nam News newspaper has reported that the government has asked the Ministry of Construction and related agencies to complete the formulation of technical standards, regulations and instructions in relation to the use of slag as well as researching new applications for it. The Ministry of Industry and Trade has also started inspecting storage sites to ensure that it doesn’t exceed two years worth of production. The government initiative has been made in response to rising stockpiles of slag, ash and gypsum.

US: The US Department of Energy has awarded a grant of US$1.5m to a combined industry and academic team led by Cornell University’s School of Civil and Environmental Engineering. The team will research uses of slag and other waste products from steel production. The study aims to investigate the overall material efficiency of steel production in order to reduce waste. It will explore several avenues, including the use of recovered silica for heavy metals capture at industrial plants and the synthesis of calcium carbonate from slag for use in steel production. Additionally, the team hopes to produce useable iron oxide from the by-products.

Assistant professor Greeshma Gadikota said, “This exciting project directly addresses our societal mission of meeting our resource needs in an environmentally sustainable manner. Iron and steel use is ubiquitous in our infrastructure.” She added that the study is “A unique opportunity to engage and train our students in developing innovative technologies that are central to our ability to live.” The study’s title is ‘Integrated reuse and co-utilisation of slag, sludge and dust with inherent heavy metal capture and nanoscale calcium carbonate production as an enhanced fluxing agent in steel plants.’

Japan: Taiheiyo Cement, JFE Steel and the Global Institute for Environmental Technology are working together to develop a carbon capture and storage system. The system will use wet alkaline earth metals extracted from steel slag to produce carbonates from exhaust gases at cement and steel plants. The partners are investigating the possibility of using these carbonates, specifically calcium carbonate and magnesium carbonate, as additives in cement production at Taiheiyo Cement’s plants. Taiheiyo Cement president Masafumi Shigehara said, “With the effects of climate change becoming apparent both in Japan and overseas, the importance of global warming counter-measures is increasing.”

Germany: Loesche says it is continuing its research and development of a process to create a steel slag suitable for cement production following a legal dispute.

The engineering company has worked with the FA Finger-Institut für Baustoffkunde (FIB) at Bauhaus-Universität Weimar on the thermally reductive modification of steel slags for recycling iron and manufacturing ‘steelworks clinker.’ It has developed two procedures for thermally reductive conditioning of BOF (Basic Oxygen Furnace) slag that have been registered for a patent, which largely differ in the respective cooling process for the remaining molten metal. The individual stages of the procedure have already been tried and tested on an industrial scale. Loesche’s partner for the entire procedure is Primetals Technologies based in Linz, Austria, which has industrial-scale plants for reduction and fast cooling based on patented procedures in its product range. The remaining iron (approximately 8 - 10%) that is still in the ‘steelwork clinker’ can then be separated in a Loesche mill. The separation procedure for this, which has also been patented by Loesche, has been in operation for approximately six years to recycle stainless steel from stainless steel slags in a recycling plant in Belgium.

However, following smelting trials conducted with the Bundesanstalt für Materialforschung und -prüfung (BAM) in 2011, Loesche faced a lawsuit regarding the patents for its procedures. The legal uncertainty that this created led to the suspension of further development and implementation of the two procedures for more than three years. The legal dispute was resolved in December 2017. The second conditioning procedure – the fast cooling – was assigned as the sole property of Loesche. A third of the ownership of the first conditioning procedure - slow cooling – was conceded to the BAM, represented by the German government.

Loesche now plans to implement the second procedure into industrial practice.

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.