Displaying items by tag: Tarmac

Cement 2 Zero (C2Z) has officially launched in the UK this week. The project is an industrial scale pilot of the Cambridge Electric Cement (CEC) process. The Materials Processing Institute will lead on this stage with two-year funding of around Euro7m provided by UK Research and Innovation (UKRI). Partners include the University of Cambridge, Atkins, Balfour Beatty, Brewster Brothers, Celsa Group, Day Aggregates and Tarmac.

CEC’s method uses recycled concrete paste in place of lime-flux in steel recycling. Slag is formed as the steel melts and this is then used in place of clinker to make more cement. This way of making cement cuts out the decarbonisation of limestone step from conventional clinker production. If renewably-sourced electricity is used to power the heating and grinding parts of manufacture, then cement production in this way could potentially cut out most of its CO₂ emissions. The first phase of trial melts by C2Z will be conducted by the Materials Processing Institute using a 250kg induction furnace and this will be scaled up to 6t in an electric arc furnace (EAF). Later, industrial scale melts will be tested in Celsa Steel's EAF in Cardiff, Wales.

CEC is taking a similar approach to HeidelbergCement with its research into using recycled concrete paste. However, HeidelbergCement says it is using the paste to help capture CO₂ in an enforced carbonation step it is testing at cement plants. It too though wants to create a secondary cementitious material (SCM) afterwards. There are also links here to construction and demolition waste and electric cement kilns as covered by Global Cement Weekly previously. The latter is different with regards to what CEC is doing because it is recycling concrete waste to produce an SCM (slag) rather than using an electrically powered kiln to make clinker from limestone. Coolbrook, VTT and the like have had to build electric kilns effectively from scratch or adapt technology from elsewhere for their approaches whilst CEC appears to be about to use existing EAFs in its industrial scale pilot.

Figure 1: Projection of how the Cambridge Electric Cement production process could be used at scale in the UK. Source: UK FIRES. Click to view larger version.

CEC’s forecast of how its process could be used at scale in the UK can be seen above in Figure 1. If the majority of the country’s steel scrap was recycled in this fashion each year then 2.4Mt/yr of CEC cement could be produced. This would represent a quarter of the c10Mt of cement sales reported by the MPA in 2021. Assuming the EAFs were powered by renewables then this could reduce the cement sector’s CO₂ emissions significantly. Although it would still leave the industry looking for other decarbonisation routes for the other three-quarters of cement demand.

C2Z and CEC offer a novel spin on cement production by recycling concrete waste, using an electrical heating step and dodging the process emissions associated with normal ordinary Portland cement (OPC) clinker production. If it did progress to a commercial stage then it would see a continued relationship between steel and cement producers. Currently this is mainly centered around iron and steel slag usage as a SCM. One point of interest here would be how much higher levels of steel recycling and a process like CEC being used regularly would affect existing slag usage as an SCM. It doesn’t look like CEC could solve the cement sector’s CO₂ emission problem all on its own but it could certainly make a difference if it progressed to a commercial stage. As ever with cement sector decarbonisation there appear to be a range of options available to producers.

UK: Tarmac has appointed Craig Kirkland as the plant manager of Tarmac’s integrated Dunbar plant in Scotland. Kirkland first started working for the subsidiary of Ireland-based CRH in the mid-1990s as its Landfill & Recycling Manager. He later became its Commercial Manager in 2015 before becoming the Head of Transformation at the Dunbar plant in 2021.

UK: Tarmac has successfully produced lime at its Tunstead, Derbyshire, plant using net zero hydrogen to fuel its kiln. The achievement was the culmination of a series of trials substituting various proportions of hydrogen for natural gas.

Tarmac’s lime director Graham Cooper said “Lime has been manufactured in the Peak District for centuries and this forward-thinking project aims to ensure the future of this nationally significant industry as the UK transitions to net zero.”

UK: Tarmac has supplied its Toptint Glow glow-in-the-dark concrete for a major mixed-use commercial development called The Glass Yard in Chesterfield, Derbyshire. Construction company Blue Deer used Toptint Glow in the main walkways and first-floor balconies of the office, restaurant and retail complex. France-based Chryso supplied its Lumintech glow-in-the-dark chippings for use in the concrete. The supplier said that the chippings are fully recycled. They are available in white, stone, light grey, agate and jade to match the colour of the concrete mix. Each has a corresponding glow colour of blue, green turquoise or blue turquoise. Tarmac says that glow-in-the-dark concrete helps to enhance the nighttime built environment.

Product development manager Glanville Norman said “Tarmac is always looking to develop new and exciting materials that can complement bold design. This is the first time that Toptint Glow has been used on a major commercial development and we were delighted to be able to propose a solution that not only has high aesthetic and environmental quality but also helped to improve safety and visibility.”

In the two and a half years since Calix brought together cement producers across corporate and national boundaries to form the first Low Emissions Intensity Lime And Cement (LEILAC-1) consortium and commissioned a carbon capture installation at the Lixhe cement plant in Belgium on 10 May 2019, carbon capture and storage (CCS) has passed some major milestones. New installations have made Global Cement headlines from Canada (at Lehigh Cement’s Edmonton plant in November 2019) to China (at a China National Building Material (CNBM) plant in July 2021). Twelve other European cement plants now host current or planned carbon capture trials – including the first full-scale system, at HeidelbergCement’sBrevik plant in Norway. A second Calix-led project in Germany, LEILAC-2, attracted Euro16m-worth of funding from the European Union in April 2020.

The work of LEILAC-1 – backed by HeidelbergCement, Cemex, Lhoist, Tarmac and others, with Euro12m in funding – set the benchmark in innovation. Its pilot plant successfully captured 100% of 'unavoidable' process emissions by indirectly heating raw materials inside a vertical steel tube. Called direct capture, the model removes a CO₂ separation step, as our subsequent price analysis will reflect.

In October 2021, the LEILAC-1 consortium published its report of the concluded Lixhe trial. It described the three-fold key successes of the study:

1) Both limestone and raw meal may be processed;

2) CO₂ is successfully separated;

3) The energy penalty for indirect calcination is not higher than for conventional direct calcination.

Additionally, Calix’s first departure into the cement sector has demonstrated that its model exhibits no operational deterioration, does not suffer from material build-up and has no impact on the host plant when used in cement production. The plant’s clinker capacity remained the same as before the trial. Most importantly of all, the Lixhe cement plant recorded no process safety incidents throughout the duration of the trial.

The study has also put an evidence-based price tag on industrial-scale CCS at a cement plant for the first time: Euro36.84/t. Figure 1 (below) plots the full-cycle costs of three different carbon capture installations at retrofitted 1Mt/yr cement plants using 100% RDF, including projections for transport and storage. Installation 1 is an amine-based carbon capture system of the kind installed in the Brevik cement plant’s exhaust stack; Installation 2 is the Calix direct capture system and Installation 3 consists of both systems in combination. Direct capture’s costs are the lowest, while the amine retrofit and the combination installation are close behind at Euro43.68/t and Euro43.25/t respectively.

Figure 1: Full-cycle costs of three different carbon capture installations at retrofitted 1Mt/yr cement plants using 100% RDF

Installations 1 and 3 both entail additional energy requirements for the separation of CO₂ from flue gases and air. With the inclusion of the CO₂ produced thereby, the cost of Installation 1 rises to Euro94/t of net CO₂ emissions eliminated, more than double that of Installation 2 at Euro38.21/t. The combination of the two in Installation 3 costs Euro67.3/t, 76% more than direct capture alone. Figure 2 (below), breaks down the carbon avoidance costs for each one and compares them.

Figure 2: Carbon avoidance costs of three different carbon capture installations at retrofitted 1Mt/yr cement plants using 100% RDF

The Global Cement and Concrete Association (GCCA)’s seven-point Roadmap to Net Zero strategy puts CCS at the forefront of concrete sector decarbonisation. CCS is expected to eliminate an increasing share of global concrete’s CO₂ emissions, rising to 36% in 2050 – by then 1.37Bnt of a total 3.81Bnt. This will depend on affordability. Calix’s model has reduced the capital expenditure (CAPEX) of a carbon capture retrofit by 72% to Euro34m from Euro98m for the amine-based equivalent. When built as part of a new plant, the CAPEX further lowers to Euro27m. Both models may also be retrofitted together, for Euro99m. In future, Calix expects to install direct capture systems capable ofachieving Euro22/t of captured CO₂. By contrast, the cost of emitting 1t of CO₂ in the EU on 11 October 2021 was Euro59.15.

In what it calls the Decade to Deliver, the GCCA aims to achieve a 25% CO₂ emissions reduction in global concrete production between 2020 and 2030, in which CCS plays only a minor part of less than 5%. LEILAC-1 presents a visionof affordable carbon avoidance which complements cement companies’ 2030 CO₂ reduction aspirations.

Unlike conventional CCS methods, however, direct capture only does two thirds of a job – eliminating the emissions of calcination, but not combustion. This would appear to make it unsuited to cement’s longer-term aim of carbon neutrality by 2050 in line with the Paris Climate Accords’ 2°C warming scenario. On the other hand, direct capture is not designed to work alone. Calix recommends use of the technology in conjunction with a decarbonised fuel stream to eliminate the plant’s remaining direct emissions. This increases the price - by 47% to Euro56.05/t of CO₂ avoided for biomassand by more than double to Euro104.48/t for an E-kiln.

The Lixhe cement plant’s carbon capture story is one of a successful crossover from one industry into another: Calix previously applied the technology in the Australian magnesite sector. Realisation of the Calix carbon capture vision in the global cement industry is a challenge primarily due to the scale of the task. It will require continued collaboration between companies and with partners outside of the industry. Further than this, parliaments must continue to enact legislation to make emission mitigation the economic choice for producers.

UK: Tarmac has completed a seven-week repair job on its PC2000 backhaul excavator at its Dunbar, East Lothian, quarry. The East Lothian Courier newspaper has reported that the work consisted of a rebuild of all major components, including the 11t bucket, pins and bushes. The equipment has been in service since 2014. It will next require servicing in 2026. Marubeni Komatsu carried out the work.

Quarry manager Mark Grieve said “With the excavator playing an absolutely key role in our process, this was a major project for Tarmac Dunbar.”

UK: Archaeologists have completed the excavation of a 52-grave cemetery dated to 3rd century Roman Britain at Ireland-based CRH subsidiary Tarmac’s Knobb’s Farm quarry in Cambridgeshire. The company said that the find is remarkable for its high proportion of decapitated bodies (33%), indicating the proximity of an execution site. The graveyard is situated near a settlement on a peninsula in the Fens wetland area. The settlement itself is lost to the quarrying activities of the previous owner.

UK: Tarmac has renewed its partnership with the Peak District National Park until 2026. Under the partnership, the company organises volunteering and funds an engagement conservation job role at the national park in Derbyshire. Since 2016, volunteers from Tarmac’s Tunstead quarry have built dry stone walls, restored a footbridge and helped to manage ancient hay meadows. In several areas of the park, volunteers have also replaced benches.

Tunstead quarry stone and powders director Pete Butterworth said that he was ‘delighted’ about the renewal. He added, “By sponsoring the engagement role, we also enable many people to get involved in practical projects which make a significant contribution to the maintenance and improvement of this beautiful area.”

UK: Tarmac, part of Ireland-based CRH, has relocated reptiles to purpose-built bespoke habitats at its Bellhouse, Essex, quarry. The reptiles lived in an area of planned quarry expansion. Work began in 2016 on the new habitat for grass snakes, common lizards and slow worms, consisting of acid grassland, tussocks and ponds. The company plans to expand the reserve under its site restoration process. It says that this will enable reptile populations to grow.

Restoration manager Enrique Moran Montero said, “The restoration phase of a quarry provides so many opportunities to promote local fauna and flora, and we pride ourselves in making the most of this land. From nature reserves to parks and wildlife learning zones for schools to use, we always strive to provide benefits for local wildlife as well as the communities we work in.”

UK: CRH subsidiary Tarmac has appointed Chris Bradbury as the plant manager at its integrated Dunbar cement plant in East Lothian, Scotland. He previously worked at Tarmac’s Tunstead plant in Derbyshire. Bradbury began working in the cement industry as an apprentice in 1994 and has held many roles at plants both in the UK and in Nigeria and the Philippines.