Displaying items by tag: Steel slag

Canada/US: Harsco’s Environmental division has invested US$2.3m in Carbicrete, a Canadian technology company developing concrete products made with steel slag for the construction industry. The investment will give Harsco Environmental a Board seat in Carbicrete and has been made in conjunction with a US$1.6m grant from the Government of Canada’s Sustainability Development Technology Canada Foundation and applications to further government grant programs. Harsco’s investment will aid the development of the technology through a demonstration program with support from a commercial concrete block manufacturer as part of a development consortium.

“This investment in innovation is aligned with Harsco’s on-going expansion into environmentally-focused products and services, and we are proud to support the development of this exciting technology,” said Harsco Environmental chief operating officer Russ Mitchell.

Carbicrete is developing a technology that allows the production of concrete without using cement by using steel slag instead. The concrete mix is poured into molds, like conventional concrete, and is then cured using CO₂. During curing, the gas becomes a solid, binding together the slag granules, and giving the concrete its strength. Carbicrete says the process can be implemented in any precast concrete manufacturing plant. It also says that the technology is ‘carbon negative’ because more CO₂ is consumed than emitted during the process.

China: The Ministry of Ecology and Environment has accused the Gaoyi Iron and Steel Company in Yuncheng in Shanxi province of illegally and dumping steel slag over a 10 year period. The ministry has named the steel producer as part of an initiative to name and shame industrial polluters, according to Reuters. The steel producer was ordered in 2013 to build a slag treatment yard but it failed to do so. So far in 2018 it has produced 0.3Mt of steel slag. Most of this has been dumped on nearby farmland.

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.

Japan: Steel slag production fell by 2.1% year-on-year to 36.7Mt in the financial year that ended in March 2018, according to Japan Metal Daily. This was attributed to increasing levels of slag recycling rates with nearly all of the blast furnace slag being reused.

China: The Ministry of Ecology and Environment has banned imports of steel slag from the end of 2018. It is part of 16 scrap metal and chemical waste products, according to Reuters. A further 16 items will be banned by the end of 2019. The government’s crackdown on waste imports is part of a ‘war on pollution.’

India: The Ministry of Steel has asked that the Ministry of Agriculture examine using slag from steel and iron production as a fertilizer. The government is particularly interested in using slag in areas with acidic soils, mostly in the eastern part of the country where productivity is lower, according to the Financial Express newspaper. 49M hectares of the country’s arable land has acidic soils from a total of 142M hectares total land that can be farmed.

US: Legislation removing the ‘waste’ classification of steel slag in Pennsylvania has received final approval in Pennsylvania. The bill will now been sent to the state governor for enactment, according to the New Castle News newspaper. Previously, mills and slag processors had to obtain special classification from the state Department of Environmental Protection to sell the product.

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.