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Strength of a refractory material changes with temperature

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Tushar Khandhadia, General Manager – Production, Udaipur Cement Works Limited, takes us through the workings of refractories at a cement plant while giving important inputs about their maintenance.

Tell us about the types of refractoriesused in your organisation and their respective purposes.
In our organisation, various types of refractories are utilised to withstand the extreme conditions present in the production of cement. These refractories are chosen based on their properties and suitability for specific areas within the cement manufacturing process. Here are common types of refractories used in our plant and their respective purposes:
Alumina refractories: Alumina refractories, typically made from alumina (Al2O3), are used in the kiln and cooler areas of the cement plant due to their high refractoriness and resistance to alkalis and abrasion.
Magnesia (magnesite) refractories: Magnesia refractories, made from magnesite (MgO), are used in the burning zone of the rotary kiln where temperatures are extremely high. They exhibit excellent resistance to alkaline materials present in the cement process.
Silica refractories: Silica refractories, composed primarily of silica (SiO2), are utilised in the lower temperature zones of the cement kiln and preheater. They provide good resistance to acidic materials and thermal shock.
Basic refractories (such as magnesia-chrome and magnesia-spinel): Basic refractories containing magnesia or chrome are employed in cement plant areas where the conditions are more basic (alkaline). They are used in high-temperature zones and exhibit resistance to alkaline materials.
Chrome-magnesia refractories: Chrome-magnesia refractories, combining chrome and magnesia, are utilised in areas exposed to higher temperatures and wear, such as cement kiln burners and coolers.
Insulating refractories (lightweight insulating bricks, ceramic fibres): Insulating refractories are used to reduce heat loss and improve energy efficiency in cement plant applications. They are employed in areas like the preheater and cooler to minimise thermal conductivity and conserve energy.
High-alumina refractories: High-alumina refractories, containing high levels of alumina, are used in areas where both high refractoriness and resistance to abrasive materials are needed, such as the transition zone of the cement kiln.

What are the key materials used in building a refractory lining to the kiln?
The key materials used during the refractory lining in a kiln include:
Alumina bricks – purpose: Alumina bricks, made of alumina (aluminum oxide), are crucial for high-temperature resistance in critical areas of the kiln, providing durability and thermal stability.
Basic bricks – purpose: Basic bricks, typically made from materials like magnesia or dolomite, are resistant to alkaline conditions. They are used in high-temperature zones of the kiln.
Key bricks – purpose: Key bricks are special bricks used to secure the refractory lining with closing each ring, providing stability and structural integrity to the overall refractory structure within the kiln.
Ceramic fibbers – purpose: Ceramic fibres, made from alumina-silicate or other compositions, serve as effective insulation in the refractory lining. They reduce heat loss and improve energy efficiency in the kiln.
Sodium silicate and mortar solution – purpose: Used as a binder or for coating refractory materials to enhance their properties and adhesion, improving the integrity and longevity of the refractory lining. The physical and chemical properties of mortars must be matched to the type of brick being installed.
Shim – purpose: Shims are thin, flat pieces of material used to fill small gaps or adjust the alignment of refractory bricks, ensuring a snug fit and proper construction of the refractory lining.

What are the key properties of a refractory that support the cement making process?
The key properties of a refractory that support the cement making process are:

  • High refractoriness
  • Chemical inertness and resistance
  • Thermal shock resistance
  • Abrasion and erosion resistance
  • Porosity and permeability
  • Mechanical strength and load-bearing capacity
  • Resistance to alkali and alkali vapours
  • Chemical composition and raw materials selection

Tell us more about the porosity and permeability of the refractory.
The porosity and permeability of refractories are important properties that influence their performance in high-temperature applications such as furnaces, kilns and other thermal processing equipment.

  • Porosity in refractories refers to the volume percentage of voids or pores within the material. It affects the refractory’s ability to retain and release gases, liquids and thermal conductivity. Low porosity is generally desirable in refractories as it leads to better thermal and chemical resistance. High porosity can result in reduced strength and thermal conductivity.
  • Permeability is the ability of a refractory material to allow the flow of gases or liquids through its pores or interconnected voids. It is influenced by the porosity and the connectivity of the pores within the material. Permeability is an essential property for refractories used in applications where gases or liquids need to flow through the refractory material, such as cement kiln.

The specific values of porosity and permeability for refractories can vary widely depending on the type of refractory material, its composition, manufacturing process, and intended application. Refractories can range from low-porosity dense materials to highly porous insulating materials, each designed for specific use cases.

What is the maximum temperature that a refractory can withhold? How does its strength differ from ambient temperature to high temperature?
Name of the spinel group mineral Composition Melting point. (oC)
Spinel MgAl2O4 (MgO. Al2O3) 2135
Hercynite FeAl2O4 (FeO. Al2O3) 1780
Picro-chromite MgCr2O4 (MgO. Cr2O3) 2350
Chromite FeCr2O4 (FeO. Cr2O3) 2075
Magnetite Fe3O4 (FeO.Fe2O3) 1591

  • silica bricks: 1400-1500°C
  • fireclay bricks: 1100-1400°C
  • high-alumina bricks: 1400-1700°C
  • magnesia/ doloma bricks: 1500-1800°C

The maximum temperature that a refractory can withstand is known as its refractoriness. Refractories are generally categorised into three main types based on their refractoriness:

  • Fireclay refractories: These have a refractoriness of around 1600oC to 1800oC.
  • High alumina refractories: They have a refractoriness ranging from about 1750oC to 1900oC.
  • Basic refractories: Spinel, Hercynite, Chromite etc. They have a refractoriness ranging from about 1750oC to 2100oC.
  • Silica refractories: Silica refractories have a refractoriness of approximately 1800oC to 1950oC

Strength of a refractory material changes with temperature. At ambient or room temperature, refractories generally have their highest mechanical strength. As the temperature increases, the strength of the refractory typically decreases due to thermal expansion, softening and possible chemical reactions. The rate and extent of this strength reduction vary based on the type of refractory and its composition.
Tell us about the installation and operating process of refractories in the kiln.
Here’s an overview of the installation and operating process of refractories in a cement kiln:
Installation of refractories

  • Preparation and inspection: Before installation, inspect the kiln’s interior to assess the condition of the existing refractory lining and identify any areas requiring repair or replacement. After selection of area clean the kiln shell area properly for fixing of bricks lining.
  • Material selection: Choose appropriate refractory materials based on the specific zone of the kiln (e.g., calcination, upper transition, burning zone, lower transition and cooling). Different
  • zones have varying temperature and chemical exposure requirements.
  • Laying the refractory bricks: Use skilled masons or technicians to install the refractories according to the design specifications. Refractory materials are laid in specific patterns to create the desired lining by using brick lining machine or kiln jack. Using of mortar are optional depend on past experience and kiln shell condition
  • Sim fastening and inspection: To tighten each ring of bricks lining use sim fastening specially in alumina bricks lining, tab each line with wooden or rubber hammer for checking tightness of ring if it is found loose reapply sim.
  • Drying and curing: Allow the refractory lining to dry and cure according to the manufacturer’s guidelines. Controlled heating and drying help to prevent cracking and ensure proper bonding.

Operating Process
Start-up and warm-up: Gradually heat up the kiln to the desired operating temperature to avoid thermal shock to the refractories. The start-up process involves slowly increasing the temperature over few hours or days for drying out the refractories and ring tighten after expansion of the bricks.
Monitoring and Control: Use advanced monitoring (shell scanner) systems to measure and controls the temperature and other critical parameters. Monitoring helps optimise the firing process and prevent damage to the refractory lining.
Refractory maintenance: Regularly inspect the refractory lining through shell temperature for signs of wear, erosion, cracks or hot spots. Start a proactive maintenance programme to repair or replace damaged refractory sections promptly.
Refractory repair and replacement: When necessary, schedule shut-downs for refractory repair or replacement. Use skilled personnel to execute repairs and ensure the new refractories are properly anchored and cured before restarting the kiln.
Cool-down: After the cement production process or maintenance activities, gradually cool down the kiln to avoid thermal stress on the refractories. Controlled cooling is essential for prolonging the refractory life.
Quality Control: Regularly assess the performance of the refractories, analyse their wear patterns, and gather data to optimise the refractory selection for future installations.
Efficient installation and careful operation of refractories in a cement kiln are vital for achieving optimal productivity, reducing downtime and extending the service life of the refractory lining. Properly maintained and installed refractories contribute to cost-effective and sustainable cement production.

What are the standards set for refractories in a cement kiln?
There are two standard shapes used in kiln for straight portion, viz. ISO shape and VDZ shape. ISO (International Organisation for Standardisation) is as per international standard and VDZ (Verein Deutsche Zementwerke) is German standard. In case of ISO brick, cold face thickness is fixed, i.e., 103 mm and in case of VDZ shape it is less than 80 mm. The average thickness for VDZ shape is fixed for all shape, i.e., 71.5 mm, that means weight for both combination shape used during lining will be same. But in case of ISO shape weight of the two types of bricks used in combination are different.
VDZ shape is prefixed with B, whereas ISO series bricks are prefixed with 3K. The last two digit represents the height of the brick or thickness of the lining in cm. e.g., B 322 means it is VDZ series brick (as B is prefix) and is having lining thickness 22 cm.
In case of basic bricks, VDZ shape is used in most of the kilns except for large kiln diameter like 6 M, where ISO shape is used for basic brick also. In case of alumina bricks, ISO shape is used in most of the kilns. However, up to 5 M dia kiln it is better to use VDZ shape for the entire length because of the following advantages:

  • Better contact / arch effect with kiln shell for VDZ shape.
  • Weight of VDZ shape brick is lower, hence easier to handle.
  • Average thickness of VDZ shape is ~20 – 25 mm lower than ISO shape.
  • Uniform compactness is achieved during green pressing of VDZ shape.
  • Uniform burning condition in case of VDZ shape during manufacturing.
  • Easier to install and minimum handing damage in case of VDZ shape.

The thickness of the lining is typical function of the kiln diameter. Recommended thickness of brick linings according to the shell diameter of rotary furnaces:

Kiln diameter Refractory thickness
up to 3.6 m 180 mm
3.6 to 4.2 m 200 mm
4.2 to 5.2 m 220 mm
Above 5.2 m 250 mm

The above table indicates the length of different zone and kiln environment at corresponding area.
Discharge zone: This is also known as cooling zone. The length of discharge zone depends on the position of burner pipe tip. Generally, it is 0 -1 times of kiln diameter i.e., for 4-meter dia. kiln, the length of this zone would be approximately 4 m. There will not be coating in this area. The brick used for this area should have high abrasion resistance. High alumina brick or spinel bonded magnesia brick is suitable for this area.
Lower transition zone: The area in between cooling and burning zone is called lower transition zone. The length varies from 1 – 2 times of kiln diameter. In this zone the coating formation on brick is unstable. Hence the brick used in this zone should have high resistance against spalling, abrasion, and chemical corrosion. Spinel bonded or hercynite bonded magnesia brick can be considered suitable for this zone. In case of very severe kiln condition (high redox condition and high chemical corrosion) zirconia-based magnesia brick may be considered.
Burning zone: The most important area of kiln where stable coating is observed is called burning or sintering zone. The length of this zone varies from three times the kiln diameter up to five times the kiln diameter. The refractory used for this area should have high temperature resistance and high chemical corrosion resistance. In low the alkali environment mag-chrome brick is apt, but in high alkali environment hercynite bonded or spinel bonded magnesia brick is suitable.
Upper transition zone: The area in between burning and calcining zone, where unstable coating is formed, is denoted as upper transition zone. The length of this zone can be 2-3 times of kiln diameter. Due to instability of coating in this zone, bricks having high thermal shock resistance should be used. Hercynite bonded or spinel bonded magnesia bricks are suitable.
Calcining zone: The area between upper transition and kiln inlet is named as calcining zone. When the calcined raw meal enters the kiln, it is usually calcined up to 92-96 per cent. Rest of the calcination of kiln feed takes place in this area. The length of this zone is 7-8 times of kiln diameter. Generally, no coating is found in this area. The brick used for this area should have high spalling resistance and resistance against alkali sulfates and chlorides. Clog shape high alumina brick having 60 and 50 per cent alumina is suitable for this area.
While using high alkali loading in kiln, phosphate bonded alkali resistant bricks are
also recommended.

Concrete

Cement Industry Backs Co-Processing to Tackle Global Waste

Industry bodies recently urged policy support for cement co-processing as waste solution

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Leading industry bodies, including the Global Cement and Concrete Association (GCCA), European Composites Industry Association, International Solid Waste Association – Africa, Mission Possible Partnership and the Global Waste-to-Energy Research and Technology Council, have issued a joint statement highlighting the cement industry’s potential role in addressing the growing global challenge of non-recyclable and non-reusable waste. The organisations have called for stronger policy support to unlock the full potential of cement industry co-processing as a safe, effective and sustainable waste management solution.
Co-processing enables both energy recovery and material recycling by using suitable waste to replace fossil fuels in cement kilns, while simultaneously recycling residual ash into the cement itself. This integrated approach delivers a zero-waste solution, reduces landfill dependence and complements conventional recycling by addressing waste streams that cannot be recycled or are contaminated.
Already recognised across regions including Europe, India, Latin America and North America, co-processing operates under strict regulatory and technical frameworks to ensure high standards of safety, emissions control and transparency.
Commenting on the initiative, Thomas Guillot, Chief Executive of the GCCA, said co-processing offers a circular, community-friendly waste solution but requires effective regulatory frameworks and supportive public policy to scale further. He noted that while some cement kilns already substitute over 90 per cent of their fuel with waste, many regions still lack established practices.
The joint statement urges governments and institutions to formally recognise co-processing within waste policy frameworks, support waste collection and pre-treatment, streamline permitting, count recycled material towards national recycling targets, and provide fiscal incentives that reflect environmental benefits. It also calls for stronger public–private partnerships and international knowledge sharing.
With global waste generation estimated at over 11 billion tonnes annually and uncontrolled municipal waste projected to rise sharply by 2050, the signatories believe co-processing represents a practical and scalable response. With appropriate policy backing, it can help divert waste from landfills, reduce fossil fuel use in cement manufacturing and transform waste into a valuable societal resource.    

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Industry Bodies Call for Wider Use of Cement Co-Processing

Joint statement seeks policy support for sustainable waste management

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Leading industry organisations have called for stronger policy support to accelerate the adoption of cement industry co-processing as a sustainable solution for managing non-recyclable and non-reusable waste. In a joint statement, bodies including the Global Cement and Concrete Association, European Composites Industry Association, International Solid Waste Association – Africa, Mission Possible Partnership and the Global Waste-to-Energy Research and Technology Council highlighted the role co-processing can play in addressing the growing global waste challenge.
Co-processing enables the use of waste as an alternative to fossil fuels in cement kilns, while residual ash is incorporated into cementitious materials, resulting in a zero-waste process. The approach supports both energy recovery and material recycling, complements conventional recycling systems and reduces reliance on landfill infrastructure. It is primarily applied to waste streams that are contaminated or unsuitable for recycling.
The organisations noted that co-processing is already recognised in regions such as Europe, India, Latin America and North America, operating under regulated frameworks to ensure safety, emissions control and transparency. However, adoption remains uneven globally, with some plants achieving over 90 per cent fuel substitution while others lack enabling policies.
The statement urged governments and institutions to formally recognise co-processing in waste management frameworks, streamline environmental permitting, incentivise waste collection and pre-treatment, account for recycled material content in national targets, and support public-private partnerships. The call comes amid rising global waste volumes, which are estimated at over 11 billion tonnes annually, with unmanaged waste contributing to greenhouse gas emissions, pollution and health risks.

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Why Cement Needs CCUS

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Cement’s deep decarbonisation cannot be achieved through efficiency and fuel switching alone, making CCUS essential to address unavoidable process emissions from calcination. ICR explores if with the right mix of policy support, shared infrastructure, and phased scale-up from pilots to clusters, CCUS can enable India’s cement industry to align growth with its net-zero ambitions.

Cement underpins modern development—from housing and transport to renewable energy infrastructure—but it is also one of the world’s most carbon-intensive materials, with global production of around 4 billion tonnes per year accounting for 7 to 8 per cent of global CO2 emissions, according to the GCCA. What makes cement uniquely hard to abate is that 60 to 65 per cent of its emissions arise from limestone calcination, a chemical process that releases CO2 irrespective of the energy source used; the IPCC Sixth Assessment Report (AR6) therefore classifies cement as a hard-to-abate sector, noting that even fully renewable-powered kilns would continue to emit significant process emissions. While the industry has achieved substantial reductions over the past two decades through energy efficiency, alternative fuels and clinker substitution using fly ash, slag, and calcined clays, studies including the IEA Net Zero Roadmap and GCCA decarbonisation pathways show these levers can deliver only 50 to 60 per cent emissions reduction before reaching technical and material limits, leaving Carbon Capture, Utilisation and Storage (CCUS) as the only scalable and durable option to address remaining calcination emissions—an intervention the IPCC estimates will deliver nearly two-thirds of cumulative cement-sector emission reductions globally by mid-century, making CCUS a central pillar of any credible net-zero cement pathway.

Process emissions vs energy emissions
Cement’s carbon footprint is distinct from many other industries because it stems from two sources: energy emissions and process emissions. Energy emissions arise from burning fuels to heat kilns to around 1,450°C and account for roughly 35 to 40 per cent of total cement CO2 emissions, according to the International Energy Agency (IEA). These can be progressively reduced through efficiency improvements, alternative fuels such as biomass and RDF, and electrification supported by renewable power. Over the past two decades, such measures have delivered measurable gains, with global average thermal energy intensity in cement production falling by nearly 20 per cent since 2000, as reported by the IEA and GCCA.
The larger and more intractable challenge lies in process emissions, which make up approximately 60 per cent to 65 per cent of cement’s total CO2 output. These emissions are released during calcination, when limestone (CaCO3) is converted into lime (CaO), inherently emitting CO2 regardless of fuel choice or energy efficiency—a reality underscored by the IPCC Sixth Assessment Report (AR6). Even aggressive clinker substitution using fly ash, slag, or calcined clays is constrained by material availability and performance requirements, typically delivering 20 to 40 per cent emissions reduction at best, as outlined in the GCCA–TERI India Cement Roadmap and IEA Net Zero Scenario. This structural split explains why cement is classified as a hard-to-abate sector and why incremental improvements alone are insufficient; as energy emissions decline, process emissions will dominate, making Carbon Capture, Utilisation and Storage (CCUS) a critical intervention to intercept residual CO2 and keep the sector’s net-zero ambitions within reach.

Where CCUS stands today
Globally, CCUS in cement is moving from concept to early industrial reality, led by Europe and North America, with the IEA noting that cement accounts for nearly 40 per cent of planned CCUS projects in heavy industry, reflecting limited alternatives for deep decarbonisation; a flagship example is Heidelberg Materials’ Brevik CCS project in Norway, commissioned in 2025, designed to capture about 400,000 tonnes of CO2 annually—nearly half the plant’s emissions—with permanent offshore storage via the Northern Lights infrastructure (Reuters, Heidelberg Materials), alongside progress at projects in the UK, Belgium, and the US such as Padeswood, Lixhe (LEILAC), and Ste. Genevieve, all enabled by strong policy support, public funding, and shared transport-and-storage infrastructure.
These experiences show that CCUS scales fastest when policy support, infrastructure availability, and risk-sharing mechanisms align, with Europe bridging the viability gap through EU ETS allowances, Innovation Fund grants, and CO2 hubs despite capture costs remaining high at US$ 80-150 per tonne of CO2 (IEA, GCCA); India, by contrast, is at an early readiness stage but gaining momentum through five cement-sector CCU testbeds launched by the Department of Science and Technology (DST) under academia–industry public–private partnerships involving IITs and producers such as JSW Cement, Dalmia Cement, and JK Cement, targeting 1-2 tonnes of CO2 per day to validate performance under Indian conditions (ETInfra, DST), with the GCCA–TERI India Roadmap identifying the current phase as a foundation-building decade essential for achieving net-zero by 2070.
Amit Banka, Founder and CEO, WeNaturalists, says “Carbon literacy means more than understanding that CO2 harms the climate. It means cement professionals grasping why their specific plant’s emissions profile matters, how different CCUS technologies trade off between energy consumption and capture rates, where utilisation opportunities align with their operational reality, and what governance frameworks ensure verified, permanent carbon sequestration. Cement manufacturing contributes approximately 8 per cent of global carbon emissions. Addressing this requires professionals who understand CCUS deeply enough to make capital decisions, troubleshoot implementation challenges, and convince boards to invest substantial capital.”

Technology pathways for cement
Cement CCUS encompasses a range of technologies, from conventional post-combustion solvent-based systems to process-integrated solutions that directly target calcination, each with different energy requirements, retrofit complexity, and cost profiles. The most mature option remains amine-based post-combustion capture, already deployed at industrial scale and favoured for early cement projects because it can be retrofitted to existing flue-gas streams; however, capture costs typically range from US$ 60-120 per tonne of CO2, depending on CO2 concentration, plant layout, and energy integration.
Lovish Ahuja, Chief Sustainability Officer, Dalmia Cement (Bharat), says, “CCUS in Indian cement can be viewed through two complementary lenses. If technological innovation, enabling policies, and societal acceptance fail to translate ambition into action, CCUS risks becoming a significant and unavoidable compliance cost for hard-to-abate sectors such as cement, steel, and aluminium. However, if global commitments under the Paris Agreement and national targets—most notably India’s Net Zero 2070 pledge—are implemented at scale through sustained policy and industry action, CCUS shifts from a future liability to a strategic opportunity. In that scenario, it becomes a platform for technological leadership, long-term competitiveness, and systemic decarbonisation rather than merely a regulatory burden.”
“Accelerating CCUS adoption cannot hinge on a single policy lever; it demands a coordinated ecosystem approach. This includes mission-mode governance, alignment across ministries, and a mix of enabling instruments such as viability gap funding, concessional and ESG-linked finance, tax incentives, and support for R&D, infrastructure, and access to geological storage. Importantly, while cement is largely a regional commodity with limited exportability due to its low value-to-weight ratio, CCUS innovation itself can become a globally competitive export. By developing, piloting, and scaling cost-effective CCUS solutions domestically, India can not only decarbonise its own cement industry but also position itself as a supplier of affordable CCUS technologies and services to cement markets worldwide,” he adds.
Process-centric approaches seek to reduce the energy penalty associated with solvent regeneration by altering where and how CO2 is separated. Technologies such as LEILAC/Calix, which uses indirect calcination to produce a high-purity CO2 stream, are scaling toward a ~100,000 tCO2 per year demonstrator (LEILAC-2) following successful pilots, while calcium looping leverages limestone chemistry to achieve theoretical capture efficiencies above 90 per cent, albeit still at pilot and demonstration stages requiring careful integration. Other emerging routes—including oxy-fuel combustion, membrane separation, solid sorbents, and cryogenic or hybrid systems—offer varying trade-offs between purity, energy use, and retrofit complexity; taken together, recent studies suggest that no single technology fits all plants, making a multi-technology, site-specific approach the most realistic pathway for scaling CCUS across the cement sector.
Yash Agarwal, Co-Founder, Carbonetics Carbon Capture, says, “We are fully focused on CCUS, and for us, a running plant is a profitable plant. What we have done is created digital twins that allow operators to simulate and resolve specific problems in record time. In a conventional setup, when an issue arises, plants often have to shut down operations and bring in expert consultants. What we offer instead is on-the-fly consulting. As soon as a problem is detected, the system automatically provides a set of potential solutions that can be tested on a running plant. This approach ensures that plant shutdowns are avoided and production is not impacted.”

The economics of CCUS
Carbon Capture, Utilisation and Storage (CCUS) remains one of the toughest economic hurdles in cement decarbonisation, with the IEA estimating capture costs of US$ 80-150 per tonne of CO2, and full-system costs raising cement production by US$ 30-60 per tonne, potentially increasing prices by 20 to 40 per cent without policy support—an untenable burden for a low-margin, price-sensitive industry like India’s.
Global experience shows CCUS advances beyond pilots only when the viability gap is bridged through strong policy mechanisms such as EU ETS allowances, Innovation Fund grants, and carbon Contracts for Difference (CfDs), yet even in Europe few projects have reached final investment decision (GCCA); India’s lack of a dedicated CCUS financing framework leaves projects reliant on R&D grants and balance sheets, reinforcing the IEA Net Zero Roadmap conclusion that carbon markets, green public procurement, and viability gap funding are essential to spread costs across producers, policymakers, and end users and prevent CCUS from remaining confined to demonstrations well into the 2030s.

Utilisation or storage
Carbon utilisation pathways are often the first entry point for CCUS in cement because they offer near-term revenue potential and lower infrastructure complexity. The International Energy Agency (IEA) estimates that current utilisation routes—such as concrete curing, mineralisation into aggregates, precipitated calcium carbonate (PCC), and limited chemical conversion—can realistically absorb only 5 per cent to 10 per cent of captured CO2 at a typical cement plant. In India, utilisation is particularly attractive for early pilots as it avoids the immediate need for pipelines, injection wells, and long-term liability frameworks. Accordingly, Department of Science and Technology (DST)–supported cement CCU testbeds are already demonstrating mineralisation and CO2-cured concrete applications at 1–2 tonnes of CO2 per day, validating performance, durability, and operability under Indian conditions.
However, utilisation faces hard limits of scale and permanence. India’s cement sector emits over 200 million tonnes of CO2 annually (GCCA), far exceeding the absorptive capacity of domestic utilisation markets, while many pathways—especially fuels and chemicals—are energy-intensive and dependent on costly renewable power and green hydrogen. The IPCC Sixth Assessment Report (AR6) cautions that most CCU routes do not guarantee permanent storage unless CO2 is mineralised or locked into long-lived materials, making geological storage indispensable for deep decarbonisation. India has credible storage potential in deep saline aquifers, depleted oil and gas fields, and basalt formations such as the Deccan Traps (NITI Aayog, IEA), and hub-based models—where multiple plants share transport and storage infrastructure—can reduce costs and improve bankability, as seen in Norway’s Northern Lights project. The pragmatic pathway for India is therefore a dual-track approach: utilise CO2 where it is economical and store it where permanence and scale are unavoidable, enabling early learning while building the backbone for net-zero cement.

Policy, infrastructure and clusters
Scaling CCUS in the cement sector hinges on policy certainty, shared infrastructure, and coordinated cluster development, rather than isolated plant-level action. The IEA notes that over 70 per cent of advanced industrial CCUS projects globally rely on strong government intervention—through carbon pricing, capital grants, tax credits, and long-term offtake guarantees—with Europe’s EU ETS, Innovation Fund, and carbon Contracts for Difference (CfDs) proving decisive in advancing projects like Brevik CCS. In contrast, India lacks a dedicated CCUS policy framework, rendering capture costs of USD 80–150 per tonne of CO2 economically prohibitive without state support (IEA, GCCA), a gap the GCCA–TERI India Cement Roadmap highlights can be bridged through carbon markets, viability gap funding, and green public procurement.
Milan R Trivedi, Vice President, Shree Digvijay Cement, says, “CCUS represents both an unavoidable near-term compliance cost and a long-term strategic opportunity for Indian cement producers. While current capture costs of US$ 100-150 per tonne of CO2 strain margins and necessitate upfront retrofit investments driven by emerging mandates and NDCs, effective policy support—particularly a robust, long-term carbon pricing mechanism with tradable credits under frameworks like India’s Carbon Credit Trading Scheme (CCTS)—can de-risk capital deployment and convert CCUS into a competitive advantage. With such enablers in place, CCUS can unlock 10 per cent to 20 per cent green price premiums, strengthen ESG positioning, and allow Indian cement to compete in global low-carbon markets under regimes such as the EU CBAM, North America’s buy-clean policies, and Middle Eastern green procurement, transforming compliance into export-led leadership.”
Equally critical is cluster-based CO2 transport and storage infrastructure, which can reduce unit costs by 30 to 50 per cent compared to standalone projects (IEA, Clean Energy Ministerial); recognising this, the DST has launched five CCU testbeds under academia–industry public–private partnerships, while NITI Aayog works toward a national CCUS mission focused on hubs and regional planning. Global precedents—from Norway’s Northern Lights to the UK’s HyNet and East Coast clusters—demonstrate that CCUS scales fastest when governments plan infrastructure at a regional level, making cluster-led development, backed by early public investment, the decisive enabler for India to move CCUS from isolated pilots to a scalable industrial solution.
Paul Baruya, Director of Strategy and Sustainability, FutureCoal, says, “Cement is a foundational material with a fundamental climate challenge: process emissions that cannot be eliminated through clean energy alone. The IPCC is clear that in the absence of a near-term replacement of Portland cement chemistry, CCS is essential to address the majority of clinker-related emissions. With global cement production at around 4 gigatonnes (Gt) and still growing, cement decarbonisation is not a niche undertaking, it is a large-scale industrial transition.”

From pilots to practice
Moving CCUS in cement from pilots to practice requires a sequenced roadmap aligning technology maturity, infrastructure development, and policy support: the IEA estimates that achieving net zero will require CCUS to scale from less than 1 Mt of CO2 captured today to over 1.2 Gt annually by 2050, while the GCCA Net Zero Roadmap projects CCUS contributing 30 per cent to 40 per cent of total cement-sector emissions reductions by mid-century, alongside efficiency, alternative fuels, and clinker substitution.
MM Rathi, Joint President – Power Plants, Shree Cement, says, “The Indian cement sector is currently at a pilot to early demonstration stage of CCUS readiness. A few companies have initiated small-scale pilots focused on capturing CO2 from kiln flue gases and exploring utilisation routes such as mineralisation and concrete curing. CCUS has not yet reached commercial integration due to high capture costs (US$ 80-150 per tonne of CO2), lack of transport and storage infrastructure, limited access to storage sites, and absence of long-term policy incentives. While Europe and North America have begun early commercial deployment, large-scale CCUS adoption in India is more realistically expected post-2035, subject to enabling infrastructure and policy frameworks.”
Early pilots—such as India’s DST-backed CCU testbeds and Europe’s first commercial-scale plants—serve as learning platforms to validate integration, costs, and operational reliability, but large-scale deployment will depend on cluster-based scale-up, as emphasised by the IPCC AR6, which highlights the need for early CO2 transport and storage planning to avoid long-term emissions lock-in. For India, the GCCA–TERI India Roadmap identifies CCUS as indispensable for achieving net-zero by 2070, following a pragmatic pathway: pilot today to build confidence, cluster in the 2030s to reduce costs, and institutionalise CCUS by mid-century so that low-carbon cement becomes the default, not a niche, in the country’s infrastructure growth.

Conclusion
Cement will remain indispensable to India’s development, but its long-term viability hinges on addressing its hardest emissions challenge—process CO2 from calcination—which efficiency gains, alternative fuels, and clinker substitution alone cannot eliminate; global evidence from the IPCC, IEA, and GCCA confirms that Carbon Capture, Utilisation and Storage (CCUS) is the only scalable pathway capable of delivering the depth of reduction required for net zero. With early commercial projects emerging in Europe and structured pilots underway in India, CCUS has moved beyond theory into a decisive decade where learning, localisation, and integration will shape outcomes; however, success will depend less on technology availability and more on collective execution, including coordinated policy frameworks, shared transport and storage infrastructure, robust carbon markets, and carbon-literate capabilities.
For India, a deliberate transition from pilots to practice—anchored in cluster-based deployment, supported by public–private partnerships, and aligned with national development and climate goals—can transform CCUS from a high-cost intervention into a mainstream industrial solution, enabling the cement sector to keep building the nation while sharply reducing its climate footprint.

– Kanika Mathur

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