Connect with us

Economy & Market

Maximising AFR in Cement Manufacturing

Published

on

Shares

Shreesh A Khadilkar, Consultant and Advisor, and Former Director Quality and Product Development, ACC Ltd Thane, discusses the importance of optimising the use of alternative fuel and raw materials (TSR percentage) in cement production without affecting clinker quality, in part one of this two-part series.

Over the past decade or so, the Indian cement industry has made significant progress in terms of improvement in energy efficiency and productivity. However, the use of alternative fuel and raw material (AFR) to replace coal for thermal energy needs, remains an area where the Indian cement industry is yet to catch up with global benchmarks. Though a few cement plants co-process large quantities and varieties of AFR in their kilns, and are reported to reach a level of around 40 per cent Thermal Substitution Rate (TSR), many plants are still at much lower levels of TSR percentage.
Most of the cement plants have now installed co-processing facilities or are on the verge of having one. Some of the plants also have pre-processing facilities, which could include shredding, segregation, impregnation, foreign body removal etc., while some others source a pre-processed solid AFR (RDF, MSW, Industrial waste sludges, agro wastes etc.).
This article shares important aspects such as assessment of clinker quality in plant clinker quality optimisation, influence of alkalis, chlorides and SO3, effects of some important minor constituents and subsequently discusses the concept for maximising AFR (TSR percentage) without affecting clinker quality through with or without use of XRD technique for in process control. The author further recommends bi-hourly quality and in process dashboard for consistent kiln performance and consistent clinker quality.

Assessment of Clinker Quality
The clinker quality assessment can best be done by Lab Ball Mill grinding of day average clinker with mineral gypsum (with SO3 of the lab ground cement targeted at 2.2 to 2.4 with fixed grinding time to achieve Blaine’s of around 300-320 M2/kg with the residue on 45 microns of the cement in range of 18 per cent to 20 per cent, at this fineness, the clinker is observed to clearly depict changes in clinker reactivity in terms of changes in 1 Day strengths of cements (± 3 to 5 MPa). At lower grinding Blaine’s (of around 250 M2/kg), which is presently being practiced by many cement plants, one does not observe the changes in clinker reactivity, as the difference of 1 Day compressive strengths is only ± 1 MPa, which does not show the changes in clinker reactivity.
Typically, clinkers with good reactivity are observed to show 1 Day strengths in lab ground cements of 30 to 35 MPa. Higher values being observed when clinker alkali sulphates are high (especially with Petcoke as fuel), the achieved Blaine’s and quantity of nibs removed from the lab ground cement, in the fixed grinding time is also indicative of clinker grindability. Judicious raw mix optimisation with existing or alternative corrective materials (with the fuel mix used by the plant) can be attempted so as to have a clinker with improved reactivity/hydraulic potential. In a running plant the approach has to be by attempting small gradual changes to clinker composition and assessing the impact of the changes, on kiln performance and clinker quantity.
The changes to be attempted could be indicated through data analysis.
In each plant, the QC and process has detailed analysis data of the day average clinkers along with its lab ground cement test results. It is also suggested to test at least one spot clinker per day for chemical parameters and physical tests of lab ground cement. From the analysis data it could be observed that on some days the lab ground cements show much higher strengths. Why on some days or in some spot clinkers, the clinker reactivity is suddenly very good? Such clinkers should be preserved and evaluated by XRD, so as to identify the optimum clinker composition which shows higher reactivity. Such an evaluation could also indicate at times the impact of changes in fuel / sources of coal / proportions of coal and Petcoke (even source of Petcoke) / solid AFR usage levels.
Typically, the target clinker composition to give a good hydraulic potential would be with LSF of 93 to 95 with a bogues potential C3S of >55 per cent clinker (especially with Petcoke as main fuel in fuel mix), with C3A (6.5 per cent to 8.5 per cent) if the clinker is used for PPC/PSC and also for OPC (especially if OPC is supplied to RMX customers) and SM 2.2 to 2.4 A/F 1.2 to 1.4. In plants where clinker MgO is higher (> 4.5 per cent), besides having the LSF target of around 93 to 95, the minimum clinker lime targeted should be such to have C/S ratio of 2.95 to 3.1 for having good clinker reactivity in spite of high clinker MgO.

Co-Processing of AFR (Liquid AFR /Solid AFR)
The properties of AF(R) co-processed in the calciner have an impact on environment, health and safety, plant operations and product quality as shown in Table 1:

  • Alkalis without sulphidisation: Formation of orthorhombic C3A, fast setting
  • Alkali sulphates (Na2SO4, K2SO4, 2CaSO4.K2SO4 or even Ca-langebnite): Increased early strength, usually shows decrease of later age strengths. Changes must be accounted for in gypsum optimisation
  • Excess of sulphur over alkalis
  • Integration of SO3 in C2S and/or formation of CaSO4
  • Possible reduction of final strength could be observed
  • Reduces the CaO availability for C3S formation
  • The clinker could be harder to grand
  • Changes the Clinker Liquid Characteristics which affects the phase formations
  • Chlorides tend to be higher in AFR liquid/solid, the control on chlorides is necessary to prevent inlet/cyclone jamming and to have < 0.06 per cent in clinker, so that the OPC has <0.04 per cent chlorides and is suitable for
  • RMC/structural concrete. To avoid problems of kiln inlet and cyclone jamming caused by SO3 and Cl. Preferably maintain the Hot Meal (2 Cl + SO3) < 3.5. The threshold value for a given plant needs to
    be assessed.

If the value goes above the plant threshold value, immediate actions of adding caustic soda for 2 to 3 shifts (in small polyethene bags) should be done to remove the depositions and avoid kiln stoppage.

Effects of some minor constituents on the clinker quality

Effects of ZnO

  • Zinc in clinker nearly distributes evenly between the silicates ad matrix phases (with preference to ferrite), trigonal C3S and ß C2S is stabilised by zinc.
  • Presence of zinc reduces the amount of aluminates in favour of alumino ferrite.
  • Each 1 per cent zinc reduces aluminates by
    1 per cent and increases alumino-ferrites by
    2 per cent.
  • Zinc is very effective flux and mineraliser, it lowers clinkerisation temperatures and accelerates lime combination. Knofel reports increased comp. strengths by up to 20 per cent and above at early ages.

Effects of TiO2

  • The clinker TiO2 should be <0.7 per cent, it should be noted that TiO2 is a viscous flux like Al2O3 and so for understanding the clinker liquid property for good C3S formation and based on the kiln conditions adjust the clinker Fe2O3 contents accordingly.
  • At higher TiO2, contents for improved kiln conditions the clinker Fe2O3 content needs to be much higher which is aggravated if clinker SO3 is higher (which also affects the viscosity of clinker liquid)
  • At high total liquid the clinker becomes silica deficient and so free lime tends to be higher (with clinker balls with calcined un sintered material inside)
  • In plants that use red mud especially with petcoke due to its higher alkalis, many sources of red muds also have TiO2, the plant should target Al2O3 + TiO2 as the viscous flux and then adjust the clinker Fe2O3 to get good kiln conditions as indicated above. Targeting higher liquid only increases the limestone LSF from mines and also affects clinker grindability.

Effects P2O5 sources

  • Many types of agriculture waste, biowastes, phosphate sludge, paint sludges, medical waste, RDF/municipal solid waste, expired detergent, cow dung cakes, etc.
  • Under Indian conditions of clinker phase composition, any increase of P2O5 contents can substantially affect clinker quality.
  • When higher P2O5 are present, the dicalcium silicate (C2S) is stabilised and inhibits formation of alite (C3S) i.e can decrease the percentage of C3S although bogue may show high percentage C3S.
  • When P2O5 present exceeds 0.4 per cent in the clinker it reduces the percentage of C3S by 10 per cent and 1 Day Comp. Strengths by around 5-6 MPa with negative effects on clinker reactivity and setting of cement.
  • Use of wastes containing phosphates in controlled manner so that P2O5 in the clinker (maximum limit in clinker is 0.25 per cent) can enhance the use of agricultural waste or use of other wastes with P2O5. It may be noted that in some regions limestone and laterite also have shown P2O5 contents.
  • In some plants up to 5 to 7 per cent TSR there is no impact observed on quality or productivity, however as the TSR/AFR percentage is increased say above >8 per cent to 10 per cent, the kiln conditions get frequently disturbed with a very high dust generation and there is a drop in clinker reactivity/quality.

In the plants a judicious study of process conditions and understanding the burnability of kiln feed could help achieve productivity without affecting the clinker quality with increased AFR/TSR.

In one of my consultancy visits to an integrated plant, similar observations as above were reported. In a brainstorming discussions with the plant process, production and QC teams, it was noted that:

  • There was substantial variation in calciner outlet/kiln inlet material/C6 material temperature it fluctuated from around 920oC to as low as 860oC, these changes in temperatures nearly corresponded with the fluctuation in percentage of moisture and feed rate of solid AFR (SAFR), RDF and other solid wastes.
  • The kiln torque decreased below the desired levels, when the calciner outlet and kiln inlet material temperatures (in this case C6 material temperatures) were less than 890oC and the kiln performance showed high dust recirculation/generation.
  • The bi-hourly XRF analysis of clinker showed lower LSF/high free lime. The decrease in clinker LSF was understandable as the SAFR ash showed a higher percentage of ash.

It was decided to collect hot meal samples 900oC to 910oC and 920oC to 930oC and also corresponding clinker samples collected after 40 minutes of the sample collection time of hot meal samples. The hot meal samples were analysed for XRD and clinker samples for XRF (Chemical analysis with free lime) and XRD (for clinker phase formation).
The XRD analysis of hot meal samples is shown in Table 2.
The XRD analysis indicates that:

  • The calcination percentage is much higher than the convention DOC of hot meal samples.
  • The un-combined CaO decreases with increase in temperature of collected sample.
  • The total belite increases with increase in temperature.

It was observed in the plant that when attempts were made to maintain the kiln inlet material temperature at 910oC to 920oC, the kiln torque showed an improvement and the kiln performance improved. The clinker quality showed improvements with lower free lime. However due to the fluctuations in ash percentage content of SAFR the clinker LSF showed lower values during the day. As a corrective action, lime sludge (available at the plant) was added on the SAFR conveyor. These corrective actions helped achieve a consistent improved clinker quality.

About the author:
With an MSc in Organic Chemistry from Jodhpur University (now JNV University), Shreesh Khadilkar joined ACC’s Organic Chemical Product Development Division in 1981 and later transitioned to the Cement R&D Division as a technical assistant. He took over as VP of R&D (Quality and Product Development Division) and retired as Director of the department in 2018, with over 37 years of experience in cement manufacturing and cements/cementitious products.

Concrete

Nuvoco Vistas launches Limla cement plant, expands Gujarat footprint

Published

on

By

Shares

Nuvoco Vistas opens a 2 MMTPA grinding unit at Limla, entering Gujarat and advancing its target of 35 MMTPA capacity by FY 2028.

Surat (Gujarat)

Nuvoco Vistas Corporation Ltd, a part of Nirma Group and one of India’s leading building materials company, has inaugurated the Limla Cement Plant in Surat (Gujarat), one of Vadraj Cement Limited’s (VCL) principal manufacturing facilities. The commissioning represents a key milestone in Nuvoco’s acquisition and restoration of VCL, while supporting the company’s expansion across the Western Indian cement market.

Vadraj Cement Limited is a subsidiary of Nuvoco Vistas Corporation Limited and has installed cement capacity of 6 MMTPA across its assets. The Limla inauguration therefore represents the first operational step in the acquired platform’s wider revival, while the Kutch facilities provide clinker supply, mineral security and coastal logistics support for the western business.

Nuvoco completed its acquisition of Vadraj Cement Limited, then under the Corporate Insolvency Resolution Process, after paying a consideration of Rs 1,800 crore in June 2025. VCL’s asset portfolio comprises a clinker unit at Kutch and a grinding unit at Limla in Surat. It also includes high-quality captive limestone reserves and a captive jetty at Kutch, supporting more efficient logistics. Following the takeover, Nuvoco began an extensive programme of restoration, refurbishment and expansion at both locations, leading to the commissioning of the Limla plant.

The Limla Cement Plant is expected to support a phased increase in sales volumes across Gujarat. It will also help Nuvoco supply neighbouring markets in Western Maharashtra and release cement capacity from its northern plants, which can consequently be redirected towards markets in North India. The plant will manufacture a full portfolio comprising Ordinary Portland Cement, Portland Slag Cement, Portland Pozzolana Cement and Portland Composite Cement. It will additionally produce the complete Nuvoco Duraguard range, including the premium Nuvoco Duraguard Microfibre product. The acquisition is also expected to generate operational synergies with Nuvoco’s existing plants at Nimbol and Chittorgarh in Rajasthan, improving logistics optimisation and market reach across important regional markets.

The grinding unit at the Limla Cement Plant was completed ahead of schedule, with 2 MMTPA of capacity now inaugurated to expand Nuvoco’s operating scale and customer reach. After Vadraj Cement’s assets become fully operational, plants in North and West India are expected to account for nearly 40 per cent of Nuvoco’s total cement capacity. This will broaden the company’s manufacturing network, strengthen access to high-growth markets and support its plan to increase consolidated cement capacity to 35 MMTPA by FY 2028, reinforcing its longer-term growth strategy.

Commenting on the development, Jayakumar Krishnaswamy, Managing Director, Nuvoco Vistas Corp Ltd, said: “The inauguration of the Limla Grinding Unit in Surat is an important milestone in Nuvoco’s growth journey and demonstrates our commitment to disciplined, value-accretive expansion. Gujarat is strategically significant for Nuvoco, with substantial opportunities arising from infrastructure investment, industrial growth, rapid urbanisation and continuing demand from the housing and construction sectors. The facility strengthens our regional footprint, improves operational flexibility and increases our ability to serve customers across northern and western markets with greater reliability and efficiency.”

He added: “Through the Vadraj acquisition, we have refurbished and restarted a strategically important asset, returning it to operations in record time through strong execution and collaboration between teams. The achievement demonstrates our ability to create value from acquired assets, fulfil our commitments and retain the confidence of stakeholders. It also highlights the strength of our project delivery capabilities and our continued focus on building sustainable, profitable growth over the long term.”

Nuvoco Vistas Corporation Limited is a building materials company whose vision is to build a safer, smarter and more sustainable world. It is among the leading players in East India and has a significant presence across North and West India. Nuvoco began operations in 2014 with a greenfield cement plant at Nimbol, Rajasthan. It later acquired Lafarge India Limited, which had entered India in 1999, followed by Emami Cement Limited in 2020 and Vadraj Cement Limited in April 2025. The company has also announced an expansion in eastern India through a new grinding mill at the Arasmeta Cement Plant, supported by several debottlenecking programmes involving equipment upgrades, process improvements and internal capacity initiatives. These developments place Nuvoco on track to achieve total cement capacity of approximately 35 MMTPA. The company reported total income of Rs 11,362 crore in FY 2025-26, reflecting its continuing growth trajectory.

Nuvoco operates a diversified portfolio across three segments: Cement, Ready-Mix Concrete and Modern Building Materials. Its cement portfolio includes Concreto, Duraguard, Double Bull, PSC, Nirmax and Infracem, covering Ordinary Portland Cement, Portland Slag Cement, Portland Pozzolana Cement and Portland Composite Cement. Its pan-India RMX business provides value-added products under Concreto for performance concrete, Artiste for decorative concrete, InstaMix for ready-to-use bagged concrete, X-Con covering M20 to M60 grades, and Ecodure for specialised green concrete. Nuvoco has supplied materials to projects including the Mumbai-Ahmedabad Bullet Train, Birsa Munda Hockey Stadium in Rourkela, Aquatic Gallery at Science City in Ahmedabad, and metro railway projects in Delhi, Jaipur, Noida and Mumbai.

Continue Reading

Concrete

Green Construction Through Cement Innovation

Published

on

By

Shares

Indian Cement Review (ICR) and Fuller Technologies brought industry, policy and technology leaders together to discuss how cement innovation can drive green construction at scale, writes Rakesh Rao.

India is building at a pace few countries can match. Highways, airports, housing, logistics parks, industrial corridors and urban infrastructure are reshaping the country’s economic geography. But beneath this growth story lies a difficult question: can India continue to build at scale without locking itself into a high-carbon future?

That question formed the core of an online panel discussion titled “Driving Green Construction Through Cement Innovation”, organised by Indian Cement Review (ICR) in association with Fuller Technologies as the Presenting Partner on June 25, 2026. The webinar brought together experts from cement technology, R&D, global industry platforms, building performance policy and international development cooperation to examine how low-carbon cement and material innovation can accelerate India’s green construction transition.

The discussion came at a crucial time. India has committed to achieving net-zero emissions by 2070 and reducing the carbon intensity of its economy by 45 per cent by 2030. At the same time, the country’s construction sector is expanding rapidly, driven by urbanisation, infrastructure development, housing demand and industrial growth. Cement, as one of the most widely used construction materials, sits at the heart of this transition. It is indispensable to development, but also central to the challenge of reducing embodied carbon in buildings and infrastructure.

Moderated by Nitika Krishan, Senior Urban Infrastructure and Sustainable Policy Consultant, the panel featured:

  • Kiranmai Sanagavarapu, Director, Low Carbon Solutions, Fuller Technologies;
  • Dr Hemantkumar Aiyer, VP and Head R&D, Nuvoco Vistas Corp Ltd;
  • Devika Wattal, Innovation Lead, Global Cement and Concrete Association (GCCA);
  • Dr Sunita Purushottam, MD, GBPN India (Global Buildings Performance Network); and
  • Vaibhav Rathi, Senior Technical Advisor, GIZ (the German Agency for International Cooperation)

Setting the tone for the discussion, Nitika Krishan underlined the scale of the challenge before the sector. “The question before us is no longer whether we build, but how we build sustainably,” she said. She pointed out that construction accounts for nearly 40 per cent of global energy-related carbon emissions when both operational and embodied carbon are considered. Cement production, she added, remains one of the hardest industrial processes to decarbonise.

For India, this is not merely an environmental issue. It is a development issue, a competitiveness issue and increasingly, a market issue. As one of the world’s largest cement producers and among the fastest-growing construction markets, India’s material choices will influence the carbon trajectory of its built environment for decades. As Krishan observed, sustainability solutions in economies such as India must not remain limited to laboratory success. They must be scalable, commercially viable and practical at national level.

The innovation gap: From technology to market

Experts believe that there is a need to bridge the innovation gaps for making decarbonisation in cement and concrete scalable. Devika Wattal of GCCA, explained, “The starting point must be the core cement manufacturing process itself. The first and foremost is the heart of our process, the heart of cement manufacturing. How do we reduce clinker? That is always a topic where industry is working very intrinsically.”

Clinker reduction remains one of the most important pathways for lowering emissions in cement. Since clinker production is energy-intensive and chemically emits carbon dioxide, reducing the clinker factor through supplementary cementitious materials (SCMs), blended cements and new chemistries can have a significant impact. Wattal also noted that carbon capture, utilisation and storage (CCUS) will have a role, though it may not be the first lever for all markets.

However, she stressed that innovation cannot stop at technology development. A solution that works in the lab must also be adaptable to industry, scalable in production and acceptable in construction practice. “It is important for that innovation to be adaptable, to be scalable, and so that it can be executed in real time,” she said.

Wattal also called for stronger enabling systems around innovation. These include performance-based standards, product-level embodied carbon databases and clearer frameworks for evaluating green materials. Without these, low-carbon cement products may struggle to compete with conventional materials in procurement and design.

R&D must balance carbon, cost and performance

Bringing in the R&D perspective into the discussion, Dr Hemantkumar Aiyer of Nuvoco Vistas emphasised that low-carbon cement development cannot be treated as a single-variable exercise. Cement must perform in real construction conditions. It must deliver strength, durability, consistency and cost competitiveness, while also reducing carbon.

“The root of understanding and balancing all these aspects lies in materials, and knowing the materials,” he said.

According to Dr Aiyer, R&D teams must understand the variability of raw materials such as fly ash, slag and clinker. Different sources produce different material behaviours. This makes mix optimisation, material characterisation and processing-property relationships critical. When performance is affected, cement manufacturers must understand how strength enhancers, admixtures and other performance chemicals interact with the material system.

He also linked material science with process efficiency. Clinkerisation takes place at extremely high temperatures, around 1,400 to 1,450 degrees Celsius. Any improvement in raw mix design, process control or energy optimisation can, therefore, help reduce emissions and cost. Dr Aiyer pointed to artificial intelligence-based optimisation, Cement 4.0 tools and advanced software as important enablers for real-time process and material control.

“The more you understand the materials, the more you can control it,” he said.

LC3: The promise is proven, the sequencing is not

Limestone calcined clay cement, commonly referred to as LC3, has attracted global attention because it can reduce clinker content significantly by using calcined clay and limestone while maintaining performance in many applications. Kiranmai Sanagavarapu of Fuller Technologies said the technology itself has already moved beyond proof of concept. Fuller Technologies has worked with calcined clay technology for nearly two decades and has seen plants running in France and Ghana. These plants, she said, are meeting local and national specifications, while the economics are beginning to make sense.

“The calciner is performing, the economics is stacking up, it is making business sense to produce,” she said.

But if the technology is viable, why has adoption not scaled faster? For Sanagavarapu, the answer lies in project sequencing. Too often, clay characterisation happens after equipment is specified. This, she warned, is a backward approach because calciner design depends on clay mineralogy, kaolinite content, iron levels, reactivity, moisture and other variables.

“If you don’t know what your deposit looks like before you commit for the equipment, you are, in a way, going blind into designing,” she said.

She also identified permitting and plant integration as major bottlenecks. Environmental clearances, mining permissions and local regulatory approvals must begin early. Similarly, calcined clay must be integrated into existing grinding, blending and logistics systems from the design stage, not treated as an afterthought during commissioning.

India already has IS 18189:2023 standard for LC3, but Sanagavarapu pointed out that the standard is not yet visible enough in procurement documents. “The gap between what is technically being permitted and what the procurement is asking is the single biggest bottleneck,” she said.

In her view, successful scale-up depends on getting the sequence right: clay characterisation first, permitting in parallel, standards aligned with construction, and integration built into plant design.

India’s LC3 journey: Progress, but demand remains thin

Providing details of India’s LC3 commercialisation experience, Vaibhav Rathi of GIZ noted that JK Cement carried out the first commercial production of LC3 at its Rajasthan plant, followed by JK Lakshmi Cement three months later. These initiatives were supported by the International Climate Initiative of the Government of Germany, with IIT Delhi contributing deep institutional knowledge on LC3 research and BIS certification.

Rathi said India’s early experience has produced clear lessons. One of the biggest was the need to build capacity among regulators. While BIS certification existed, State Pollution Control Boards were unfamiliar with the technology and unsure about the approval pathway.

“The capacity building is not just needed amongst the producer and the users of the cement, but also the regulators who are working with this technology for the first time,” he said.

He also highlighted the need for better information on China clay deposits. Since China clay is currently classified as a minor mineral, centralised data on availability, quality and location is limited. If cement manufacturers are to adopt LC3 at scale, stronger mineral intelligence will be important.

The third issue is demand. LC3 has already been used in projects such as Palava City in Mumbai and Noida International Airport, but these remain limited examples. “It is in a chicken and egg situation,” Rathi said. “Cement companies are saying we need more demand, and users are saying there is not enough cement available.”

Public procurement, he suggested, could help break this cycle. If agencies such as CPWD and other public bodies begin testing, accepting and specifying LC3, it could create the market confidence needed for cement companies to invest in production and storage.

Building codes must catch up with innovation

Dr Sunita Purushottam of GBPN India argued that material choices will determine built environment emissions over the long term, but India’s current policy signals remain fragmented. Although LC3 has received BIS recognition, she pointed out that building codes, municipal bylaws, schedules of rates and sustainability codes do not yet provide uniform guidance on low-carbon cement.

“The current cement regulations are largely prescriptive and favouring traditional materials,” she said. This limits the ability of alternative materials to compete on performance, durability and emissions.

Dr Purushottam also raised the issue of taxation. Cement, including LC3, currently falls under the same GST bracket as conventional cement. A differentiated tax structure, she argued, could help accelerate market adoption. “In order for the market to demand LC3, that differentiation in the GST could go a long way,” she said.

She noted that green building certifications such as IGBC and GRIHA are already creating demand for low-carbon materials by assigning points for embodied carbon and sustainable material use. However, she said large-scale adoption will require regulatory mandates, particularly through building codes and state-level notifications.

She also cautioned that low-carbon cement alone does not solve the entire building performance problem. A material may reduce embodied carbon, but the operational carbon of a building depends on thermal performance, design, insulation and energy use. “The energy part has two elements,” she said. “One is the embodied carbon of the material itself, and the other is the operational carbon.”

Collaboration is the bridge between invention and impact

Wattal said GCCA sees innovation as a strategic priority and works through platforms that connect industry with academia and start-ups. “There is no way we will decarbonise our sector without innovation,” she said.

However, she stressed that research must be connected to actual industry challenges. Innovations developed in isolation may fail when they encounter real-world barriers such as raw material variability, plant integration, cost, standards and finance. Start-ups, too, need industry mentorship and scale-up pathways.

Wattal also flagged the importance of finance. Even strong technologies may struggle to attract investment if there is no common understanding of bankability. “We have always put projects into, is this a bankable project? But the definition of a bankable project has never been defined,” she said.

For India, she saw strong potential in its academic and start-up ecosystem, but said the challenge lies in alignment and prioritisation. The country has the research base, industrial capacity and market size. What it now needs is a coordinated route from innovation to deployment.

There is a practical concern for cement manufacturers: how can existing plants be adapted for lower emissions without compromising reliability or commercial viability?

Kiranmai Sanagavarapu addressed, “The reliability risk in calcined clay retrofit is definitely real, but it is almost always self-inflicted. The risk arises when a new process is added to an existing circuit without properly redesigning grinding and blending configurations.”

Existing cement plants, she explained, can take two broad routes. The first is external sourcing of calcined clay combined with mill optimisation. This requires lower capital investment and can potentially move in 12 to 18 months if other conditions are in place. It may reduce emissions by around 20 to 30 per cent. The second route is integrated calcination on site, which requires higher capital expenditure and longer lead times, but provides greater control over quality, supply and emissions reduction potential.

For Sanagavarapu, the principle is simple: low-carbon retrofits must be designed with intent. “Design it with an intent properly from the start. Start in the market conditions where the economics are already working,” she said.

Circularity: The overlooked advantage

According to Vaibhav Rathi, fly ash and slag are already well established in cement and construction (C&D), but construction and demolition waste remains underutilised. “C&D waste is a growing business opportunity which not many have taken up,” he said. India’s continuous construction and demolition activity creates huge volumes of waste, much of which contributes to air pollution, land degradation and material inefficiency. With the right processing and standards, this waste can be converted into useful construction products.

Rathi also pointed out that LC3 has a circular economy dimension that is often overlooked. It can use low-grade kaolin-rich clay left behind after high-grade clay is extracted for other applications. “LC3 is not only a low-carbon solution, but also a circular economy solution,” he said.

At the same time, he cautioned that LC3 in India is not yet cheap because it has not reached scale. Site-specific techno-commercial feasibility studies, supported jointly by development agencies and industry, could help companies assess whether LC3 production makes technical and financial sense at a given location.

Dr Purushottam added that India must address both low-carbon cement and construction waste together. “Both low-carbon cement and C&D waste go hand in hand. India does not have an option but to work on both,” she said.

Dr Aiyer called for policy shifts from both government and industry, including preferential purchasing of sustainable materials, minimum supplementary cementitious material requirements in public and public-private projects, and faster regulatory implementation. “If we can fast-track the regulatory standards and their implementation on the ground, that is the way to go,” he said.

From green ambition to green construction

Cement innovation is no longer only about chemistry. It is about systems. Low-carbon cement will scale only when technology, standards, procurement, finance, regulation, education and construction practice move together.

LC3 and other low-carbon technologies have shown promise. India has early commercial examples, strong research capability and growing market interest. But mainstream adoption will depend on whether demand can be created, regulators can be capacitated, standards can be embedded in procurement, and manufacturers can see a clear business case.

For a country building at India’s scale, the opportunity is enormous. Cement will continue to be central to infrastructure and urban development. The challenge now is to ensure that the cement used in India’s growth story carries a lower carbon burden.

  • Rakesh Rao

Participate in Cement Expo 2026 and discover how next-gen infrastructure can be built with innovations in cement.

Continue Reading

Concrete

Indian Railways Plans Green Fly Ash Transport Network

Published

on

By

Shares

Specialised rail logistics will move fly ash from power plants to infrastructure industries.

New Delhi

Indian Railways is planning a large-scale green logistics initiative to transport fly ash from thermal power plants to industries where it can be reused in infrastructure and construction activities.

The initiative was discussed during a review meeting chaired by Union Minister for Railways Ashwini Vaishnaw. Union Ministers of State for Railways V Somanna and Ravneet Singh Bittu were also present.

India generates nearly 340 million tonnes of fly ash every year from thermal power plants. The proposed initiative aims to create an efficient rail-based transport system using specialised containers and dedicated logistics arrangements to move fly ash safely from power plants to end-use industries.

Fly ash is widely used in road construction, cement manufacturing, brick production, concrete, blocks and boards. By improving its movement through the railway network, the initiative is expected to support better utilisation of this industrial by-product while reducing environmental concerns linked to storage and disposal.

The move also aligns with India’s circular economy goals by converting waste from thermal power generation into a useful raw material for the construction and infrastructure sectors. Wider availability of fly ash can help reduce material costs in areas such as bricks and cement, supporting more affordable infrastructure and housing development.

Through this initiative, Indian Railways aims to provide a cleaner, safer and more organised transport solution for fly ash, turning an environmental challenge into an infrastructure resource.

Continue Reading

Video Thumbnail

    SIGN-UP FOR OUR GENERAL NEWSLETTER


    Trending News

    SUBSCRIBE TO THE NEWSLETTER

     

    Don't miss out on valuable insights and opportunities to connect with like minded professionals.

     


      This will close in 0 seconds