Displaying items by tag: ground granulated blast furnace slag

A trio of slag cement stories have been in the sector news this week with reports from Australia, France and Sri Lanka. Of note from the first two reports is a focus on supplies of slag.

The first concerns Hallett Group’s US$80m supplementary cementitious materials (SCM) project in South Australia. This will see the company process slag and fly ash sourced from sites in the region to manufacture blended cement products and standalone SCMs. These will be principally milled, blended and distributed from a site at Port Augusta. However, an additional distribution site at Port Adelaide is also planned that can both import and export the company’s products in a bid to cut down on supply chain risk, particular for its mining customers. The company says it will replace up to 1.15Mt/yr of cement when fully operational, although initial production looks set to be about a third of this based on local media reports. Commissioning of the Port Adelaide distribution hub is scheduled for May 2023, following by the Whyalla Granulator in January 2024 and the Port Augusta processing plant in June 2024. Pointedly, Hallett Group is explicit about where is plans to source its SCMs from: Nyrstar Port Pirie and, potentially, Liberty GFG.

The second slag-themed story hails from France, where Hoffmann Green Cement has acquired ABC Broyage, which operates a slag grinding plant in North Dordogne. Like the project in Australia above, Hoffmann Green is focused on its supply chain. With this acquisition it will be able to grind its own blast furnace slag instead of buying it. Raw blast furnace slag will be imported via the port of La Rochelle where the company has storage silos. It will then be ground at the former ABC Broyage site and sent on to Hoffmann Green’s H1 and H2 production sites, located at Bournezeau in the Vendée region. Finally it will use it to manufacture its H-UKR and H-IONA cement products. There is no mention of how much the acquisition is costing Hoffman Green. Instead the emphasis, according to company founders Julien Blanchard and David Hoffmann, is very much to, “strengthen our control over our supply and secure our margins in the current highly inflationary context.”

Finally, the week’s third slag-themed cement story is from Sri Lanka, where local media reports that Insee Cement has started producing Portland Composite Cement, using SCMs such as slag, at its Ruhunu grinding plant. This story follows the trend of cement producers around the world switching to greater usage of blended cements, often for sustainability reasons. Unfortunately, political events in Sri Lanka are overshadowing everything else locally, with the president having fled amid social unrest provoked by the ongoing and severe economic crisis. To this end Insee Cement has astutely also donated medical supplies this week to the intensive care unit at the Colombo National Hospital.

These slag stories are important for the cement sector can be demonstrated by a recent update to the Center for International Climate and Environmental Research - Oslo’s (CICERO) research on global CO₂ emissions from cement production. When it published its estimate for 2021 it found that overall emissions were 2.6Bnt in 2021 or just over 7% of the world’s total CO₂ output. What is worse though, is that its data suggests that cement-based emissions have steadily grown year-on-year from 1.2Bnt in 2002. Apart from a dip in 2015 they have kept on rising! This can mostly be attributed to the growth of the Chinese cement industry in the early 2000s suggesting that a tipping point may be reached in the current decade as lowering cement production CO₂ intensity finally kicks in.

Slag and other SCM-based blended cements fit in here as they are one of the ‘easiest’ ways to reduce the clinker factor of cement and concrete and thereby reduce the sector’s CO₂ levels. Hence they keep popping up on the various roadmaps and reports for the cement industry to reach net zero. The flipside of this however is that slag is becoming harder to source as the demand for granulated blast furnace slag increases and less new steel plants get built, especially in North America and Europe. Hence the focus on the supply of slag in the first two news stories above. Blended cements may be the future but getting there will be far from simple.

Australia: Hallett Group plans to establish a slag cement grinding plant in Port Augusta, South Australia. Magnet News has reported the cost of the project as US$83.9m, towards which the producer has received US$13.4m in government funding. The plant will produce cement using South Australian ground granulated blast furnace slag (GGBFS) from Nyrstar’s Port Pirie and Liberty Primary Steel’s Whyalla steel refineries and fly ash from the site of the former Port Augusta power plant. Its operations will be 100% renewably powered. An accompanying new distribution facility at Port Adelaide will ship the cement to markets. The project will create 50 new jobs.

When the Port Augusta grinding plant becomes operational in 2023, its products will reduce regional CO₂ emissions by 300,000t/yr, subsequently rising to 1Mt/yr, according to the company’s expansion plans.

Hallett Group chief executive officer Kane Salisbury said "We're talking about 1% of the entire country's 2030 [CO₂ reduction] commitment, delivered through this project." Salisbury added "We're looking at turning South Australia into a global leader in manufacturing green cement."

UK: Aggregate Industries and Coomtech have partnered to develop low-energy kinetic drying technology for pulverised fuel ash (PFA) from power plant. The partnership will see Aggregate Industries use Coomtech’s kinetic dryers in its PFA processing, as part of its effort towards increasing the volume of waste materials incorporated in its products to 3Mt/yr from 1.5Mt/yr by 2025. The project has attracted funding from the UK government Department of Business, Energy and Industrial Strategy (BEIS).

Chief commercial officer Chris Every said “We’re delighted to have the support of Aggregate Industries in this grant project. Coomtech is especially pleased to have the business’ ongoing technical and commercial input to the project operation and analysis of performance. In addition, the opportunity to work together with a brand that is leading the way in creating new materials that will prove fundamental to the future of the construction sector and meet net zero objectives.” Every continued “The added benefit of our new drying technology is its flexibility - providing the potential to dry a wide range of materials being considered to aid the greening of the cement industry, including limestone, ground blast furnace slag (GBFS), natural pozzolans and other crushed and milled minerals that can offer an activated character to combine in cement and concrete mixes.”

France: Hoffmann Green Cement Technologies has acquired ABC Broyage, which operates a slag grinding plant in North Dordogne. The producer says that ABC Broyage will import granulated blast furnace slag (GBFS) via La Rochelle and supply ground GBFS to its H1 and H2 green cement plants in Bournezeau. This will give Hoffmann Green Cement Technologies self-sufficiency in its raw materials processing.

Co-founders Julien Blanchard and David Hoffmann said “Managing our supply chain has always been one of Hoffmann Green's strategic priorities. After securing our supplies of co-products and their storage, we are now focusing on optimising their processing through the acquisition of ABC Broyage and the development of vertical integration.” Blanchard and Hoffmann noted that, besides strengthening the company’s control over its raw materials supply, ABC Broyage’s slag grinding capacity also secures its margins in the ‘current highly inflationary context.’

India: Three new Indian concrete companies have separately secured agreements for the use of Finland-based Betolar’s Geoprime alkali-activated slag and fly ash additive. Reuters News has reported that the companies are Balaiji Cement Products, Shiv Tiles and SNEH Precast. Engineering company Godrej & Boyce has also signed a letter of intent with the supplier for pilot production of concrete blocks, paving slabs and other elements.

Betolar expects producers to achieve global concrete production volumes of 250,000t/yr of concrete containing Geoprime by 2023.

Brazil: The Falcão Bauer Quality Institute (IFBQ) has certified LafargeHolcim Brasil’s CP III-32 blast furnace slag cement for all construction applications. The certificate confirms that the product offers 50% reduced CO₂ compared to the average cement on the Brazilian market.

The Jornal Dia Dia newspaper has reported that sustainability manager Bruno Hallak said “The IFBQ is an institution recognised by the market and this certification confirms that we are on the right track. The production processes and methodologies evaluated can even be reproduced in other units, according to their local characteristics, increasing the gain for the environment.”

LafargeHolcim Brasil previously obtained IFBQ certification for its CP III-40 blast furnace slag cement, which offers a slightly less reduced clinker factor than CP III-32 cement, in 2021. It was the first cement of its type in Brazil to receive the certification. The company produces both cements at its Vitória grinding plant in Espírito Santo.

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.

France: Eqiom has launched its new reduced-CO₂ CEM II/C cement range on the French market. The range includes the Portland limestone, slag and clinker filler CEM II/CM (SL) 42.5 N cement produced at its La Rochelle cement plant. The cement is the first product to obtain NF certification from the Scientific and Technical Center for Building (CSTB) under its new standard designation EN 195-5. The producer says that in mid-2022 EN 197-5 will assimilate into the EN 206/CN standard for use in structural concrete.

Eqiom said that the range will offer its customers a more sustainable alternative to its other NF EN 197-1 certified compositions. La Rochelle cement plant operations manager Ahmed Mansouri said “We are proud of this result, which is the result of close collaboration between the different Eqiom teams. This commitment has made it possible to provide our customers with a solution with low CO₂ emissions while guaranteeing sufficient performance so as not to impact practices on the construction sites.”

Vietnam: Vicem Hoàng Mai Cement has announced a full-year sales target of US$79.2m for 2022, down by 1.5% year-on-year from 2021 levels. Its target net profit for the year is US$656,000, more than five times its 2020 figure. The company forecasts cement production of 1.73Mt, up by 11% from 1.56Mt, and clinker production of 1.4Mt, down by 4.1% from 1.46Mt, for the year. It plans to replace 30 – 40% of the natural gypsum currently used in cement production with synthetic gypsum. It will also increase the proportion of ash and slag in its raw materials mix.

The Chúng Khoán newspaper has reported that Vicem Hoàng Mai Cement said that it is experiencing increased costs due to high raw materials and fossil fuel prices. A coal shortage has also disrupted production.

From the Nordics to the Mediterranean, European countries lead the field in reduced-clinker cement production using supplementary cementitious materials (SCMs). While consumers, faced with ever-greater choice, continue to opt for sustainability, projects to improve existing SCMs and develop new ones have won government backing and have become a matter of serious investment for other heavy industries beside cement. European cement producers’ decisions are steering the course to a world beyond CEM I. Yet, even in Europe, great untapped potential remains.

Companies generated a good deal of marketing buzz around their latest reduced-CO₂ cement ranges in 2021 and the first quarter of 2022: Buzzi Unicem’s CGreen in Germany and Italy, Holcim’s EcoPlanet in six markets from Romania to Spain, Cementir Holding’s Futurecem in Denmark and Benelux, and Cemex’s Vertua in Spain and several other countries. All boast reduced clinker factors through the use of alternative raw materials. This, however, is really a rebranding of a long-established norm in Europe.

Since 2010, cements other than CEM I have constituted over 75% of average annual cement deliveries across Cembureau member countries (all cement-producing EU member states, plus Norway, Serbia, Switzerland, Turkey, the UK and Ukraine). This statistic breaks down differently from country to country. CEM II is the norm in Austria, Finland, Portugal and Switzerland, with deliveries in the region of 90%. Portland limestone cement (PLC) makes up a majority of deliveries in all four. It has been central to Switzerland’s transition to 89% (3.72Mt) of CEM II deliveries out of a total 4.18Mt of cement despatched in 2021. There, the main types of cement were CEM II/B-M (T-LL) Portland composite cement, with 1.38Mt (33%), and two different classifications of PLC: CEM II/A-LL PLC, with 1.28Mt (31%), and CEM II/B-LL PLC, with 888,000t (21%).

A second approach is that of the Netherlands, where CEM III blast furnace slag cement with a clinker factor below 65% predominates, favoured for its sulphate resistance and the protection it offers against chloride-initiated corrosion of steel reinforcement in marine settings. By contrast, the UK has traditionally maintained a higher reliance on CEM I cement. This can be partly explained by the preference of builders there for adding fly ash or ground granulated blast furnace slag (GGBFS) at the mixing stage. Nonetheless, CEM II Portland fly ash cement held a 14% (1.43Mt) market share in the UK’s 10.2Mt of cement consumption in 2021.

The UK Mineral Products Association (MPA) has identified limestone as an underutilised resource in the country’s cement production. Together with HeidelbergCement subsidiary Hanson Cement, it has applied for a change to National Application standards to allow the production of Portland composite cement from fly ash and limestone or GGBFS and limestone. The association has forecast that Portland composite cement could easily rise to 30 – 40% of UK cement consumption, and that this has the potential to eliminate 8% of the sector’s 7.8Mt/yr-worth of CO₂ emissions.

Metallurgical waste streams have long flowed into European cement production, primarily as GGBFS, but also as bauxite residue. In 2021, alumina production in the EU alone generated 7Mt of bauxite residue, of which the bloc recycled just 100,000t (1.4%) that year. Two projects – the Holcim Innovation Center-led ReActiv project and Titan Cement and others’ REDMUD project – aim to produce new alternative cementitious materials from bauxite residue.

By collaborating with other industries, cement producers’ investments can most effectively reduce the overall cost of using these materials in cement production. In Germany, HeidelbergCement and ThyssenKrupp’s Save CO₂ project aims to develop new improved latent hydraulic binders or alternative pozzolan from GGBFS by producing slag from directly reduced iron (DRI). The Save CO₂ team believes that GGBFS substitution for clinker has the capacity to eliminite 200Mt/yr of CO₂ emissions from global cement production.

Meanwhile in the world of mining, ThyssenKrupp and others’ NEMO project is investigating the recovery of a useable mineral fraction for cement production from the extractive waste of the Luikonlahti and Sotkamo mines in Finland and the Tara mine in Ireland, through bioleaching and cleaned mineral residue upcycling. This may give cement producers full access to Europe’s 28Bnt stockpiles of sulphidic mining waste, of which mines generate an additional 600Mt each year.

Denmark-based CemGreen, which produces the calcined clay supplementary cementitious material CemShale, is developing a shale granule heat-treating technology called CemTower. This consists of three pieces of equipment vertically integrated into cement plants’ preheaters, kilns and coolers, and brings the processing of waste materials – here oil shale – to the cement plant.

Lastly, cement producers are exploring the possible uses of waste made of cement itself. In Wallonia, HeidelbergCement subsidiary CBR’s CosmoCem project is investigating the production of alternative cement additives from large available flows of local demolition, soil remediation and industrial waste. Similarly, the Greece-based C2inCO₂ project seeks to mineralise fines from concrete recycling for HeidelbergCement to use in the production of novel cements in its Greek operations.

In Switzerland, ZND Portland composite cement (produced using fine mixed granulate from building demolitions) is the third largest cement type, with 178,000t (4.3%) of total deliveries – narrowly behind CEM I with 239,000t (5.7%).Holcim Schweiz developed its Susteno 4 ZND Portland composite cement with Switzerland’s lack of any ash or slag supply in mind, demonstrating the potential flexibility of a circular economic approach to cement production.

On 21 March 2022, the University of Trier reported that it is in the process of mapping mineral resources, waste deposits and usable residues ‘on a cross-border scale,’ in an effort to produce new materials for use in cement production. Industry participants include France-based Vicat, CBR, Buzzi Unicem subsidiary Cimalux and CRH subsidiary Eqiom. Vicat is preparing a kiln at its 1Mt/yr Xeuilley cement plant in Meurthe-et-Moselle to use in testing new alternative raw materials developed under the project.

For Cembureau and its members, work continues, with the goal of Net Zero by 2050 constantly in sight. This goal includes a reduction in members’ clinker-to-cement ratios to well below 65%. In this, the association and its members are working towards a world not just beyond CEM I, but beyond CEM II, too. What exactly this will mean remains to be seen.

Sources

CemSuisse, ‘Lieferstatistik,’ 11 January 2022, https://www.cemsuisse.ch/app/uploads/2022/01/Lieferstatistik-4.-Quartal-2021.pdf

WSA, ‘December 2021 crude steel production and 2021 global crude steel production totals,’ 25 January 2022, https://worldsteel.org/media-centre/press-releases/2022/december-2021-crude-steel-production-and-2021-global-totals/

MPA, ‘Low carbon multi-component cements for UK concrete applications,’ July 2018, https://prod-drupal-files.storage.googleapis.com/documents/resource/public/Low%20carbon%20multi-component%20cements%20for%20UK%20concrete%20applications%20PDF.pdf

European Commission, ‘European Training Network for Zero-waste Valorisation of Bauxite Residue (Red Mud),’ 16 July 2020, https://cordis.europa.eu/project/id/636876

European Commission, ‘Industrial Residue Activation for sustainable cement production,’ 16 February 2022, https://cordis.europa.eu/project/id/958208

Recycling Portal, Zement der Zukunft – Forschungsprojekt „SAVE CO₂“ gestartet, 28 May 2021, https://recyclingportal.eu/Archive/65677

h2020-NEMO, ‘Project,’ https://h2020-nemo.eu/project-2/

European Commission, ‘Green cement of the future: CemShale + CemTower,’ 14 April 2021, https://cordis.europa.eu/project/id/101009382

CosmoCem, ‘Communiqué de Presse,’ https://cosmocem.org/

CO₂ Win, ‘C²inCO₂: Calcium Carbonation for industrial use of CO₂,’ https://co2-utilization.net/en/projects/co2-mineralization/c2inco2/

Les Echos, ‘Rendre le ciment moins gourmand en CO₂,’ 21 March 2022, https://www.lesechos.fr/pme-regions/innovateurs/des-substituts-au-clinker-rendent-le-ciment-moins-gourmand-en-co2-1395002