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The impact is clear: 40 per cent lower CO2 missions from cement

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The maths is simple: replace 30 per cent of clinker with calcined clay for up to a 40 per cent reduction in CO2 emissions. It’s smart, it’s efficient, and it’s something almost every cement manufacturer could do right now. Steven Miller, Global Process Line Manager at FLSmidth, shares insights on the naturally occurring mineral that is set to accelerate the green transition of cement.

With 7 per cent to 8 per cent of all global carbon emissions coming from cement production, the pressure is rising. Environmental regulations grow progressively more demanding. Financiers shy away from emissions-intensive investments. And around the world, citizens, governments, and a broad range of other organisations are calling for action on climate change. For the cement industry, it’s the perfect storm – and it calls for innovation and ingenuity. Right now, there is no substitution at scale for concrete. But we all know we can’t continue our current practices. To meet our sustainability commitments in line with the Paris Agreement, we need to make some radical shifts. This challenge presents a new opportunity for a centuries-old material combined with 21ˢᵗ century technology.

Step one: Cut the clinker factor
The science of the cement manufacturing process is well known. Reducing energy consumption and switching from fossil fuels to carbon neutral alternative fuels have the capability to cut CO2 emissions by up to ~35 per cent. But the majority of the CO2 coming from the manufacturing process occurs during limestone calcination. In the future, we hope these emissions will be captured before entering the atmosphere, but right now that technology is still some way off widescale availability. Instead, we have a more accessible solution: Cut the clinker factor – i.e. the quantity of clinker used in the cement mix.

For many years, cement manufacturers around the world have been doing just that. Fly ash from coal fired power plants, blast furnace slag from iron and steel manufacturing, and a range of other natural and manmade pozzolans have helped cement manufacturers achieve clinker factors as low as 0.4 for some cement types.

However, these low clinker factors are not possible across the board. They are highly dependent on local availability. And as coal-fired power is phased out and iron and steel producers work to reduce their environmental impact, the availability of these industry by-products will fall away altogether. What we don’t want is to see the clinker factor increasing again, along with emissions.

Fortunately, we have an alternative. A widely available, naturally-occurring mineral can be activated into a supplementary cementitious material that can replace 30 per cent of clinker and eliminate up to 40 per cent of CO2 emissions.

In some cases, an even higher percentage of clinker replacement is possible. Best of all, the technology to incorporate it into your process already exists. It has a low ROI, and it’s actually cheaper to manufacture than clinker. What are we talking about?

Calcined Clay – the future of green cement
Clay is found almost everywhere in the world, making it a natural solution in regions where a lack of limestone availability drives up the cost of cement. With the right treatment, it makes an excellent replacement for clinker. You may even be able to use some of the equipment you already have on site, further reducing your investment.

The process is simple. We use the best available technologies from the cement and mining industries to optimise clinker substitution while maintaining cement quality.

This begins with our established ET dryer crusher, which is especially designed for materials like clay with up to 40 per cent moisture content. Using waste gases from the preheater, feed material is dried and crushed in one operation, achieving both the required fineness and a free moisture content of just 1 per cent by the time the clay enters the preheater.

From the dryer crusher, the material is fed to the 2-stage preheater/calciner system for calcination. It’s important to note that any fuels you fire in your existing calciner can be used in the clay calciner, including up to 100 per cent waste fuels.

What colour should green cement be?
Perhaps in the future, the natural red colour of calcined clay will be a sign of a green cement. For now, however, our clay calciner includes colour control technology to ensure the final result is traditional cement grey. This will ensure easy adoption by the cement industry’s customers who have had many decades of building grey buildings, bridges and roads – and may need additional time to change their perspective on colour.

The calciner is engineered for consistent clay activation. This ensures you get the uniform product quality that enables you to substitute more clinker in your cement product. After the activated clay has been collected in the bottom stage of the calciner, it is sent to a reducing zone where the colour control process takes place. From there the clay is introduced to a series of cooling cyclones to attain a final product temperature in the range of 100 – 120˚C. Cooling is achieved using fresh air, which is then heated by the cooling clay and recovered for use as combustion air in the calciner. This is significantly more efficient than water cooling and ensures the lowest possible fuel consumption.

Elimi nate f ossil f uels by electrif ying clay calcination To further decarbonise the cement industry, FLSmidth and a series of leading industry experts have formed a new partnership called ECoClayTM.

To reduce CO2 emissions from cement production by up to 50 per cent, the ECoClay partners will develop and commercialise the technology needed to replace fossil fuels in the calcination of clay by fully electrifying the process.

Led by FLSmidth, the global ECoClay partners include US-based industrial heating expert Rondo Energy, cement producers VICAT from France and Colombian Cementos Argos, and the Technical University of Denmark.

Based on the shared research and tests on hightemperature electric heat generation, storage solutions and renewable grid integration, the ECoClay partnership will build a pilot plant at FLSmidth’s R&D Center in Denmark. The consortium will seek to demonstrate how the ECoClay process is superior to the conventional combustion processes, has a smaller physical footprint on site and significantly lower emissions of air pollutants.

According to the project plan, the ECoClay partners expect to be able to commence construction of the first full-scale electric clay calcination installation by the end of 2025.

Concrete

ACC Barmana Plant Fails Environmental Compliance

The plant has 11 air pollution control devices.

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A National Green Tribunal (NGT) joint committee has identified environmental compliance failures at Adani Group’s ACC Ltd Barmana Cement Works (Gagal), Himachal Pradesh. 
The report cited dust emissions from clinker, ash, and cement silos, inadequate safeguards against accidental discharges, and insufficient protection for local residents from dust pollution. It also noted the lack of an oil and grease removal mechanism in wastewater from truck washing and the absence of a mandated three-layer tree plantation to mitigate air and noise pollution. 
The plant has 11 air pollution control devices, including 109 bag filters and two ESPs, but is currently operating at 25% utilisation due to an annual maintenance shutdown. Mining and crushing operations remain suspended. 
(cemnet) 

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Concrete

Shree Cement Launches Bangur Marble Cement in Ranchi

The product was launched in Ranchi, Jharkhand.

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Shree Cement has introduced Bangur Marble Cement, a premium PSC cement under its Bangur Cement brand, offering high brightness, superior strength, and crack resistance. Designed for exposed concrete structures, it ensures durability and an imposing aesthetic. 
The product was launched in Ranchi, Jharkhand, and will soon be available in Bihar, West Bengal, and other states. It will be distributed through over 2,000 retailers, with in-store product demonstrations highlighting its unique features. 
Bangur Marble Cement incorporates GGBS, a steel manufacturing by-product, making it eco-friendly and highly durable while reducing the environmental footprint. Shree Cement is also adopting a digital-first approach to reach consumers, setting a new trend in the cement industry. 
This launch expands Bangur Cement’s premium lineup, which includes Jungrodhak, Rockstrong, Powermax, Magna, and Roofon. 
(Construction Week Online)  

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Concrete

Ramco Cements plans Rs 12 bn capex for FY26 and advances Rs 10 bn sale

Ramco Cements reported a profit after tax of Rs 3.25 billion.

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Ramco Cements has announced a capital expenditure (capex) plan of Rs 12 billion for the next fiscal year, maintaining its guidance for FY25. The company has raised Rs 4.43 billion this fiscal through the sale of non-core assets.

During the third quarter of the current fiscal, Ramco Cements incurred a capex of Rs 2.56 billion, bringing the total spending for the first nine months to Rs 8 billion. The company has set a target of monetizing Rs 10 billion worth of non-core assets and has realized Rs 4.43 billion so far, with an additional Rs 100 million received as advances for assets nearing finalization.

The funds generated from these asset sales have been utilised to reduce debt, bringing the company’s net debt to Rs 46.16 billion as of December 31, 2024. In Q3FY25 alone, debt reduction amounted to Rs 4.87 billion.

Ramco Cements remains on course to achieve a cement production capacity of 30 MTPA by March 2026. This expansion includes the commissioning of a second production line in Kolimigundla, capacity enhancements through de-bottlenecking, and additional grinding facilities. A railway siding at Kolimigundla is scheduled for commissioning in March 2025.

The company is also investing in sustainable energy initiatives, with a 10 MW Waste Heat Recovery System (WHRS) at RR Nagar expected to be operational by June 2025 and a 15 MW WHRS unit at Kolimigundla set to be commissioned alongside Kiln Line-2 by March 2026. A new construction chemicals unit in Odisha is expected to be ready before March 2025. Land acquisition for a greenfield project in Karnataka has progressed, with 53 per cent of mining land and 13 per cent of factory land secured.

For Q3FY25, Ramco Cements reported a profit after tax of Rs 3.25 billion, significantly higher than Rs 930 million in the previous year, primarily due to an exceptional income of Rs 3.29 billion from asset sales. Net revenue declined by 6 per cent year-on-year to Rs 19.88 billion due to a 14 per cent drop in cement prices.

Total sales volume, including construction chemicals, increased by 9 per cent to 4.37 million tonne. Cement capacity utilization saw a slight improvement to 75 per cent in Q3FY25 from 74 per cent in Q3FY24. However, EBITDA declined by 28 per cent to Rs 2.91 billion due to weaker cement prices, despite cost reductions from lower fuel prices and improved manufacturing efficiency.

News source: Hindu Businessline

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