Displaying items by tag: Steel slag

UK: SteelPhalt has launched a carbon-negative asphalt product called SteelSurf ECO+. The asphalt use 95% recycled steel slag with a lignin binder made from trees. The kraft lignin is supplied by GautamZenUK in collaboration with Stora Enso. It is used as an alternative to bitumen, which previous SteelPhalt asphalt products used instead.

"In our journey to become the world's most sustainable asphalt supplier, this is a huge step forward,” said Julian Smith, SteelPhalt Strategic Growth Director. “This product is an example of what our team’s collective passion for innovation and sustainability can deliver, while making the world a greener place.”

Steelphalt is a part of the Harsco Environmental division of US-based Harsco.

India: The first steel slag road in India has been built in Surat, Gujarat. The 1.2km road is located at Hazira Port, according to the Times of India newspaper. It was constructed by using steel slag aggregate in place of natural aggregate. The higher strength of the material has also allowed for the thickness of the road to be reduced by 30%. Around 100,000t of steel slag was used. The joint project was a collaboration between the Council of Scientific and Industrial Research, the Central Road Research Institute, the Union Ministry of Steel, government think-tank NITI Ayog and ArcelorMtttal-Nippon Steel.

US: The United States Geological Survey (USGS) estimates that the US sold 17Mt of ferrous slags in 2021, a rise of 31% year-on-year from the estimate in 2020. Blast furnace slag represented about 49% of the volume sold and accounted for 87% of the total value ofslag, most of which was granulated. Steel slag produced from oxygen and electric arc furnaces accounted forthe remainder of sales. Slag was processed by 28 companies servicing active iron and steel facilities or reprocessing old slag piles at about 124 processing plants, including some iron and steel plants with more than one slag-processing facility, in 33 States, including facilities that import and grind unground slag to sell as ground granulated blast furnace slag (GGBFS).

A further 2.2Mt was imported, a slight decline from 2020. From 2017 to 2020 the USGS reports that 42% of imported slag came from Japan, 18% from Brazil, 11% from China and 10% from Italy.

The USGS noted that during 2021, domestic GGBFS remained in limited supply because granulation cooling was known to be available at only two active US blast furnaces while, elsewhere, only one domestic plant produced pelletised slag in limited supply. Grinding of granulated blast furnace slag was only performed domestically by cement companies. However, following Covid-19 related decrease in availability in 2020, supply of steel slag increased in 2021.

Spain: Sidenor has launched Termoslag, a software for the control of slag transit during liquid steel dumping. It aims to reduce steel’s slag content by 10%, thereby reducing raw materials and energy consumption in the steel production process and increasing slag output for circular economic uses such as cement production. Sidenor said, “We are committed to eco-innovation and the circular economy.”

Australia: Boral Australia has launched Innovo, an asphalt system product that uses steel slag as a raw material amongst other recyclables. Recycled materials that can be used in the mix include steel slag, recycled plastics, tyres, recycled crushed glass, recycled asphalt pavement and printer toner. The product has been used in various projects in Queensland, New South Wales, Victoria, South Australia and Western Australia.

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.”

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.