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Revival of small scale cement manufacturing

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The availability of most of the AFR is limited or scattered which may not be economically viable for use in most of the large cement plants because of logistics, quantity, preparation and technical issues, says Dr KN Bhattacharjee.

The availability of most of the AFR is limited or scattered, which may not be economically viable for use in most of the large cement plants because of logistics, quantity, preparation and technical issues. This is a great roadblock for the effective use of AFR. However if an industry can find means to utilise its own by-product or waste in its own premises or nearby then it will be a win- win situation for all. Cement manufacturing process is a very appropriate process to recycle many industrial and agricultural wastes. The black meal process of vertical shaft kiln technology is a proven technology in China and India and can serve as a very good outlet for consuming AFR in the vicinity of industries generating the waste in small quantities.

This will also help in reducing environmental pollution. The author has carried out numerous plant scale trials with various industrial and agricultural wastes in VSK plants in India with reasonable success and feels that it may be worthwhile to go backward technology-wise to improve India’s usage of AFR. With the recognition of performance-based cements in most of the standards of world, composite cements are to gain ground and many alternate materials mainly industrial wastes can find profitable use again in small-sized cement plants.

The vertical shaft kiln (VSK) technology is an old technology of Portland Cement manufacture and even the modern versions have almost phased out from India mainly because of economics of scale and taxation issues. In China, still 30 per cent of its cement production comes from shaft kiln plants. The VSK process technology is still a workable proposition for use of wastes available in limited quantities. Also by virtue of the simple process a plethora of process issues associated with modern pre-heater, pre-calciner rotary kiln system are eradicated while using AFR. Plant scale trials with many wastes have shown improvement in VSK clinker quality and better productivity from the kilns. Also it is possible to add many wastes in small quantities directly to VSK clinker to produce high performing composite cements. Although the plan sounds to be reverse engineering but sometimes an old concept can regain its past glory due to changing national needs and environmental issues.

The modern vertical shaft kiln technology is technically sound and institutes like National Council of Cement and Building Materials (NCCBM) and the then Regional Research Laboratory (RRL), Jorhat had done a commendable work in modernising the technology in India. Also the village-based Saboo technology created a stir in India in the 80s when they brought cement manufacturing under the umbrella of small scale industry. During that period, the objective was to increase production as India was cement deficit and VSK technology was a partial answer to quickly bridge the gap between demand and supply. In the hilly terrain of North East, it is still a viable proposition to use scattered small limestone deposits in the midst of logistical challenges.

The advantages and disadvantages of black meal process of vertical shaft kiln technology:

Advantages:

  • Small scale cement production and still suitable in hilly terrains having limestone deposits for local distribution of cement.
  • Energy efficient process: Specific heat consumption is in the range 600 to 650 Kcal/kg of clinker. Specific power consumption is in the range 0f 60 to 70 Kwh/tonne OPC although authentic figures are not available. Since drying, pre-heating, calcining, burning and cooling are integrated in the same vessel, heat losses due to convection and radiation is much reduced.
  • Porous VSK clinker is much easier to grind thus cement grinding power requirement is less.
  • Very low refractory consumption as kiln is stationery and low abrasion as material flow is vertically downward with slow speed.
  • Vast scope of using AFR available in smaller quantities is the major advantage. Some alternate waste materials can act as flux or mineraliser. Mineralising ions can increase the rate of reaction in burning zone leading to complete burning in burning zone.
  • Thus the technology offers avenue not only in the use of wastes but also utilise the waste in improving burnability by stabilising phases at lower temperatures.
  • recirculation of obnoxious gases and materials which ensures smooth operation and higher productivity.
  • Due a constant bed of wet green nodules above the calcining zone the green nodules bed acts as an effective filter to arrest all dust particles. No additional gas cleaning device is required.
  • Since fuel is inter-ground with raw materials elaborate arrangement of fuel preparation and firing is eliminated
  • Very effective and controlled flow of material through flat grate using variable frequency drive (VFD). This helps to position the burning zone constantly at the same level.
  • Relatively simple machines to operate and maintain.
  • Gestation period of starting a new plant is very low.
  • No highly skilled manpower is required and local folk/plant staff can be easily trained for operations.
  • Possible to manufacture a variety of clinkers and thereafter produce various kinds of low cost Portland cements.
  • Very little chance of cold air in-leakages. Diversion of combustion air during clinker discharge has been ably dealt by either triple air locking arrangement or material block tube in the modern VSKs.
  • Since each nodule has its independent fuel system significantly higher temperatures are not achieved leading to no issues of NOx.

Disadvantages:

  • Viability can be at stake due to taxation policies and lower scale of operation. However if Government gives tax rebates on use of AFR the plants can be viable. Also it is possible to reduce cost of production by using low cost or free of cost non- conventional materials and waste fuels available locally. Maybe the savings can be shared with customers.
  • Quality issues: Many believe that VSK clinker cannot be at par with modern rotary plant clinker. In this respect a few conflicting issues are prevalent. It is true that using the same raw materials and fuel the modern rotary clinker will be better performing especially the later age compressive strengths and soundness of cements produced. However the soft burnt nature of the VSK clinker opens up possibilities of addressing customer requirements of good early age compressive strength and early setting in the case of PPC and PSC. The author has found that early age compressive strengths and setting can be matched with modern plants while making PPC with a maximum of 30 per cent fly ash absorption. The Black meal process is capable of producing sound clinkers with less than 1.5 per cent free lime and 45 per cent C3S component. The author’s experience in few VSK plants in Jodhpur-Rajasthan region supports this viewpoint. Experiences with various limestone in Northern India and Bhutan reveals that the technology cannot tolerate high magnesia limestone primarily due to the absence of rapid cooling arrangement but adding certain industrial wastes with mineralising minor constituents gives amazing results in reducing or mitigating this deleterious effect.
  • Consistency of clinker: Consistency does get affected if the raw mix is not well homogenised and nodulisation is not controlled. However these can be easily solved by using good homogenisation and blending techniques. Nodulisation can be automated to yield nodules of good strength. In some cases nodule strength can be improved by double nodulisation. Various industrial wastes like bagasse from sugar industry have been found to improve nodule strength together with bonus addition of heat value. Waste oils can be added at this stage to give very good results.
  • Heat difference between the central and peripheral charge especially in the large dia kilns of 100 TPD per day can be a matter of concern in some cases depending of raw materials and fuels used. The 50 tonne/day Saboo shaft kiln design was found to very efficient in this respect. Crust formations were found to be minimal. Dustry clinker due to beta to gamma conversion of C2S is prevalent in few cases but can be eliminated by stabilisation of phases even with the inherent disadvantage of rapid or quench cooling.

Plant scale trials using various alternate materials and fuels:

Use of pond ash, bottom ash and boiler fired rice husk ash in a 50 TPD VSK plant in Kanpur Dehat, Uttar Pradesh: Both bottom and pond ash were procured from Panki Thermal power plant and were used as components of raw mix separately as a source of Silica and Alumina by partial replacement of plastic clay by 15 to 20 per cent. There was drop in free lime from 2.2 per cent to 1.8 per cent and the dust content in clinker reduced drastically. There was increase of 1.5 to 2.0 MPa in 3 days and 3 MPa in 28days compressive strength of 43 grade OPC. The pond and bottom ash had substantial carbon particles (LOI- 15 to 20 per cent) which added some heat value and perhaps the reactivity of the raw mix increased by the presence of some amount of reactive alumino-silicates. Indirect effects noticed was smooth kiln operations with a slight increase of production from the 50 TPD VSK. Pond ash which is generally wet can be added directly during nodulisation if a dosing arrangement is designed to avoid the drying operation. Boiler fired Rice Husk was tried in the same plant which gave very good results in improving clinker quality. The material was black in colour with LOI around 10 per cent indicating unburnt carbon which must have supplemented the heat input. It was possible to add rice husk as it is but plant scale trial was not attempted with the apprehension that the husk fibres may not give a homozenised mix in the existing raw grinding arrangement.
Use of Phosphorus furnace slag, alkali bypass dust and bag house dust from a Calcium Carbide plant: All these materials were tried with a contention to capitalise mineralising effect from the wastes due to some minor constituents or the presence of reactive silica or Alumina. Even granulated blast furnace slag (GBFS) was also tried. Improvements in kiln productivity and quality was noticed of clinker in most of the cases. In VSK operation any measure which goes to ensure completion of the reactions in the short burning zone will definitely go in improving clinker quality and smooth kiln operations. Appropriate raw mix fineness with correct proportioning of waste materials and fuels, homogenisation hold the key to success.
Additions of alternate waste materials with VSK clinker to make composite cements The future of cement making is composite cements. This not will helps to use some industrial or agricultural wastes in the final product but also help to improve performance of cements and reduce the carbon footprint. In many cases it can lead to low cost cements together with better performance.

Significant improvement was observed when 5 per cent bag house dust from a calcium carbide plant was added in a quaternary mix of 60 per cent Granulated Blast Furnace slag (GBFS) and 3 per cent gypsum using VSK clinker. Initial setting time was reduced from 180 minutes to 40 minutes when compared with plain control sample of PSC. There was an improvement of 2 MPa at 3 days and 28 days compressive strength was more or less the same. Quaternary blends using Alkali bypass dust and 60 to 70 per cent GBFS , gypsum and VSK clinker also performed well in terms of faster setting and improvement of early age compressive strength. Similar results were obtained while using brick kiln ash and calcined clay Pozzolana in dosages of 15 to 20 per cent while making PPC mixes using VSK clinker.

Thus VSK clinker can act as a performance enhancer for early setting and early age compressive strength in presence of high dosage GBFS containing PSC cements and fly ash/CCP based Pozzolanic cements. Hydration studies have revealed that the soft burnt VSK clinker releases soft burnt lime at a faster rate in the early ages leading to higher quantity hydration products both with GBFS and Pozzolana.

Conclusion
The author was associated with VSK plants for six years while doing his Ph.D. His doctoral work is mainly associated with hydration studies of composite cements and VSK clinker doped with ions coming from various industrial and agricultural wastes. He feels that the black meal process using modern vertical shaft kiln technology can be a viable proposition to use localised waste materials available in limited quantities. The process simplicity of the Black Meal process opens up immense potential for use of wastes (both agricultural and Industrial) with improved cement performance in many cases. Waste generating plants can have captive VSK plants or sub let this activity to local entrepreneurs. All performance enhancements have been validated by actual hydration studies which is available with the author for anyone who is interested. This has been a part of the author’s doctoral work. The author feels that for India till we incorporate large scale AFR facilities catering to large cement plants the VSK plants can be revived mainly for use of localised AFR as the project cost and gestation period from concept to commissioning is very low.

Acknowledgement
The author is grateful to AKS University administration for allowing to publish this paper.

About the author
Prof (Dr) KN Bhattacharjee
has 37 years experience in the global cement industry. He has worked with all process technologies of cement manufacture and has done considerable work on use of AFR in mini-cement plants. His Ph.D thesis is in applied cement chemistry and his findings helped many mini-cement plants in India to improve their profitability during the late 80s. He has publications in reputed international and national journals like Cement and Concrete Research, ZKG International, Silicate Industrials, Transactions of Indian Ceramic Society, etc. After his retirement in 2016 from Dangote-Africa, he is teaching cement technology to B.Tech students in AKS University, Satna. Dr KNB has worked with ACC in India, two plants in Oman, Lafarge Canada and Dangote, Africa.

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Concrete

Protect Your Margins

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In a research-backed article, Dr SB Hegde examines why carbon-adjusted profitability and LC3 will decide the next set of winners in cement manufacturing.

The Indian cement industry has achieved world-class operational efficiency through lower specific energy consumption, high plant utilisation and a reduced average clinker factor of approximately 67.5 per cent. These traditional measures of operational excellence remain essential. However, they are no longer sufficient. Carbon now carries a measurable financial cost under India’s Carbon Credit Trading Scheme (CCTS) and under European carbon markets. Future leadership will be defined by carbon-adjusted profitability, the ability to generate strong returns while systematically lowering the carbon intensity of every ton sold.
Limestone calcined clay cement (LC3) offers a practical, scalable pathway to achieve this dual objective. By replacing up to 50 per cent of clinker with calcined clay and limestone, LC3 can reduce CO2 emissions by 30–40 per cent while delivering comparable or superior durability performance.
This article examines the technical foundations of LC3, European industrial practices, the emerging Indian carbon market and a concrete roadmap for Indian companies to embed carbon-adjusted metrics and LC3 into daily operations, incentives and commercial strategy.

Limits of traditional operational excellence
For many years, plant performance has been judged primarily by five indicators: specific heat consumption, specific power consumption, kiln and mill utilisation, clinker factor and overall equipment effectiveness. These metrics drove continuous improvement and helped the industry reduce energy use and increase the share of blended cement. Three structural changes have rendered them incomplete as sole measures of success.
First, carbon now carries a real or opportunity cost. Plants that improve volume or lower cash cost while raising or stagnating emissions intensity create a hidden liability that will surface as CCTS trading matures and as green procurement expands.
Second, lower-carbon products such as LC3 and high-performance blended cements are creating differentiated market segments. Customers in infrastructure, real estate and export-oriented construction are beginning to specify embodied-carbon limits.
Third, investors and lenders increasingly treat carbon intensity as a financial risk factor. Traditional KPIs can mask the divergence between short-term cash profit and long-term carbon-adjusted value.

What is carbon-adjusted profitability?
Carbon-adjusted profitability evaluates normal profit after explicit adjustment for carbon performance. A practical expression is:
Carbon-Adjusted EBITDA = Conventional EBITDA – Carbon Cost + Green Premium Income
Carbon cost may be an internal carbon price, the actual cost of purchasing Carbon Credit Certificates under CCTS, or the opportunity cost of high emissions relative to peers. Green premium income arises when customers pay more for verified lower-carbon cement or when the company sells surplus credits. Tracking both conventional and carbon-adjusted profit side-by-side gives management a clearer picture of value creation under evolving market rules.

Table 1. Traditional KPIs versus Carbon-Adjusted Leadership Metrics
Traditional Focus New Leadership Metric Why It Matters
Specific energy consumption Emissions intensity (kg CO2/t cement) Directly linked to future CCTS and CBAM costs
Kiln utilisation Carbon-adjusted contribution margin Reveals true value of incremental volume
Clinker factor Share of lower-carbon products sold (incl. LC3) Measures commercial success of the transition
Power cost per tonne Effective carbon cost per tonne sold Expose hidden liabilities
Absolute EBITDA Carbon-adjusted EBITDA + green premium Aligning profit with future market reality

LC3: Technical foundations and performance advantages
LC3 is a ternary blended cement that typically combines approximately 50 per cent clinker, 30 per cent calcined clay, 15 per cent limestone and 5 per cent gypsum (the classic LC3-50 formulation). The decisive technical advantage is that clay is calcined at 700–850 °C, far below the 1,450 °C required for clinker production. This lower temperature, together with the substantial reduction in clinker content, delivers CO2 reductions of 30–40 per cent relative to ordinary Portland cement (OPC).
Chemistry is synergistic. Calcined kaolinitic clay (metakaolin) reacts with calcium hydroxide from clinker hydration and with limestone to form additional C-A-S-H gel and carboaluminate phases. These phases densify the microstructure, reduce porosity and improve durability.
Field experience shows superior resistance to chloride ingress, sulphate attack and alkali–silica reaction. Early-age strength can match OPC with high-reactivity clays; later-age strengths routinely meet 42.5 and 52.5 grade requirements.
Importantly, LC3 does not require high-purity kaolin. Clays with 40 per cent or even lower kaolinite content can be activated successfully, expanding raw-material availability across India. Calcination can use adapted rotary kilns or dedicated flash calciners, making the technology compatible with existing plant infrastructure and far less capital-intensive than carbon capture.
Economic analyses show that LC3 can be produced at equal or lower cost than OPC in many locations because of reduced energy demand and cheaper clay. Life-cycle assessments consistently report 30–40 per cent lower embodied CO2 per tonne of cement.
Table 2. Comparative profile: OPC versus LC3-50
Parameter OPC LC3-50
Typical clinker content ~95 per cent ~50 per cent
CO2 emissions (relative) Baseline (≈0.85 t CO2/t cement process + fuel) 30–40 per cent lower
Clay calcination temperature Not applicable 700–850 °C
Key hydration products C-S-H, portlandite, ettringite C-A-S-H + carboaluminates
Chloride & sulphate resistance Good Superior
Production cost potential Baseline Equal or lower in most locations
Infrastructure compatibility Existing High (minor adaptations)

In India, commercial adoption has begun in earnest. JK Cement commenced the first commercial production of LC3 in the Indian subcontinent at its Mangrol plant in Rajasthan in 2025 under BIS standard IS 18189.
By early 2026, approximately 2,000 tonnes had been produced and sold, avoiding an estimated 500 tonnes of CO2. JK Lakshmi Cement followed with commercial launch of its Green PRO LC3 grade from the Jaykaypuram plant. As of mid-2026, two producers are supplying LC3 to the market. The first large-scale infrastructure application is the Noida International Airport (Jewar), where LC3 was used in the runway and a building complex, demonstrating full constructability and performance under demanding conditions. These early volumes are still small relative to national cement demand, but they mark the critical transition from pilot to commercial reality. Companies that scale capacity now will be positioned to capture both CCTS credits and emerging green-procurement demand.

Why the shift is accelerating
According to the World Bank’s State and Trends of Carbon Pricing 2026, direct carbon pricing now covers nearly 30 per cent of global greenhouse-gas emissions and generated more than US$107 billion in public revenue in 2025. The average global carbon price stands at approximately US$21 per tonne, although regional prices vary widely.
In Europe, the EU ETS price has traded near €80–85 per tonen in mid-2026. Free allocation for cement is being withdrawn in parallel with CBAM. European producers therefore face a clear signal: every tonne of avoided CO2 improves both compliance and competitiveness. Holcim has scaled calcined-clay production, including Europe’s first dedicated line at Saint-Pierre-la-Cour (France) and a second line in the Czech Republic (2026). Heidelberg Materials, Cementir (FUTURECEM) and others have commercialised low-clinker calcined-clay blends across multiple markets, showing that carbon-adjusted profitability is already reshaping capital allocation in the world’s most mature carbon market.India’s CCTS is now operational. Binding emission intensity targets apply to 186 cement facilities for FY 2025–26 and FY 2026–27. Average required reductions for integrated plants are modest (around 2.7 per cent by FY 2027), yet the direction is clear.
Trading of Carbon Credit Certificates is expected in the second half of 2026, with early prices likely in the `800–1,500 per tonne range. Plants that outperform targets can sell credits; those that underperform must buy them or face compensation. Cement is well positioned to be a net supplier of credits if clinker factor continues to fall through LC3 and other low-clinker systems.

Way forward for India
India starts from a strong baseline, world-class energy efficiency and a clinker factor already lower than the global average. The next competitive frontier is the deliberate reduction of process emissions through clinker substitution at scale. LC3 is uniquely suited to Indian conditions because suitable clays are widely distributed, the technology fits existing kiln and grinding infrastructure, and the resulting product can meet the performance demands of both infrastructure and building construction.
A practical national pathway contains five interlocking elements:

  1. Standards and acceptance: Accelerated finalisation and promotion of BIS specifications for calcined-clay and limestone–calcined-clay cements will remove a key barrier to commercial uptake. Alignment with European practice (EN 197-5) can facilitate knowledge transfer and export readiness.
  2. Supply-chain development: Investment in flash calcination capacity and systematic characterisation of regional clay deposits will secure reliable, low-cost feedstock. Existing rotary kilns can be adapted for initial volumes while dedicated calciners are built.
  3. Incentive alignment: Part of variable compensation for plant managers, sales teams and senior leadership should be linked to emissions intensity reduction and to the volume of lower-carbon products (including LC3) sold. Without this link, traditional volume and cost targets will continue to dominate behaviour.
  4. Product-level carbon accounting: Reliable measurement of emissions intensity at the individual cement grade level, supported by third-party verification where required, is essential for both CCTS compliance and credible green claims.
  5. Demand-side pull: Green public procurement policies that specify maximum embodied-carbon thresholds for major infrastructure projects will create a predictable market for LC3 and other low-carbon cements, accelerating scale and cost reduction.
    Companies that treat LC3 as a strategic product line rather than a niche offering will be better positioned to generate surplus Carbon Credit Certificates, capture any emerging green premium, and protect margins as carbon costs rise.

Organisational changes required
Technical capability alone is insufficient. Three organisational shifts are required.
Daily management: Emissions intensity must appear on the same daily and monthly dashboards as heat consumption, power consumption and utilization. Plant reviews should examine both conventional and carbon-adjusted results.
Incentives: A meaningful portion of bonuses for plant heads, technical teams and sales leadership should be tied to lower emissions intensity and successful commercialisation of LC3 and other low-carbon grades.
Commercial approach: Sales teams need clear volume and pricing targets for lower-carbon products, supported by technical service that helps customers specify and place the material correctly. Without commercial pull, excellent technical performance remains under-utilised.

Table 3. Three-stage roadmap to carbon-adjusted profitability
Time Horizon Priority Actions Expected Outcome
Next 12 months Add emissions intensity to plant dashboards; establish internal carbon price; initiate LC3 pilot production and customer trials Visibility and early organisational learning
12–24 months Revise incentive systems; scale LC3 and other low-carbon grades to key accounts; secure third-party verification capability People and sales aligned with carbon goals
24–36 months Embed carbon-adjusted metrics in board reporting and capital allocation; expand calcined-clay capacity Full system integration and competitive advantage

Questions senior leaders should ask
Boards can accelerate the transition by insisting on answers to a short list of questions:
• Is our carbon-adjusted profit improving, stable or declining relative to conventional EBITDA?
• Did recent volume growth improve or worsen our emissions intensity?
• What share of sales already comes from lower-carbon products, including LC3, and what is the trajectory?
• How exposed is our capital expenditure plan to rising carbon costs under CCTS and potential CBAM-related requirements?
• Do our incentive systems still reward only volume and cost, or have they been updated to include carbon performance?
Treating carbon with the same seriousness as energy cost or kiln utilization does not diminish operational excellence; it expands the definition of excellence to match the new competitive reality.

Looking ahead
By 2030 the gap between leading and lagging cement companies will not be decided by who records the lowest specific heat consumption. It will be decided by who delivers the strongest carbon-adjusted profits.
Absolute emissions may still rise as national production grows. That is not the issue. Companies that reduce intensity year after year and successfully sell cleaner products will pull ahead in both domestic and export markets. Those that do not will fall behind, even if their traditional efficiency numbers look strong.
Operational excellence built the Indian cement industry. It remains the foundation. It is no longer the complete picture. Carbon-adjusted profitability is the clearer measure of success.
LC3 is not a distant technology. It is available now. It cuts CO3 by 30–40 per cent, works with existing plants, and is already in commercial production in India. Companies that treat it as a strategic product, not a pilot, will protect their margins and generate tradable credits.
Leaders who act now will place carbon metrics on daily dashboards, link incentives to intensity reduction and LC3 sales, invest in calcined-clay capacity, and build commercial capability to sell lower-carbon products. They will shape the next chapter of the industry.

References

  1. World Bank. (2026). State and Trends of Carbon Pricing 2026. Washington, DC: World Bank Group.
  2. International Carbon Action Partnership (ICAP). (2026). India Carbon Credit Trading Scheme – Status and Coverage. Berlin: ICAP.
  3. Ministry of Environment, Forest and Climate Change / Bureau of Energy Efficiency. (2025). Greenhouse Gases Emission Intensity Target Rules, 2025. New Delhi: Government of India.
  4. Scrivener, K., Martirena, F., Bishnoi, S., & Maity, S. (2018). Calcined clay limestone cements (LC3). Cement and Concrete Research, 114, 49–56.
  5. RMI. (2024). The Business Case for LC3. Rocky Mountain Institute.
  6. European Commission. (2026). EU Emissions Trading System – Allowance Price Data and Free Allocation Phase-out Schedule. Brussels.
  7. Holcim. (2025–2026). Scaling Calcined Clay for Sustainable Building – Corporate Updates on European and Latin American Capacity. Zurich: Holcim Ltd.
  8. LC3 Project / EPFL. (2026). LC3 – A Guide to Best Practices for Scalable, Affordable and Sustainable Low-Carbon Building. Lausanne: École Polytechnique Fédérale de Lausanne.
  9. Business Today / Industry Reports. (2026). First Large-Scale LC3 Application at Noida International Airport, Jewar. New Delhi.
  10. NITI Aayog / Industry Analyses. (2026). Roadmap and Baseline Performance Indicators for the Indian Cement Sector. New Delhi.
  11. Springer / Innovative Infrastructure Solutions. (2026). LC3 Systems: A Review of Chemistry, Performance, Durability and Sustainability toward Market Adoption.
  12. Cementir Holding / Industry Sources. (2025–2026). FUTURECEM and Related Low-Clinker Technologies in Europe.
  13. Climate Risk Horizons & Independent Analyses. (2026). Assessment of Emission Intensity Targets under India’s CCTS for Cement and Other Hard-to-Abate Sectors.
  14. GCCA / TERI. (Various years). Decarbonization Roadmaps for the Indian Cement Industry.
  15. EN 197-5:2021. Cement – Part 5: Portland-composite cement CEM II/C-M and Composite cement CEM VI. European Committee for Standardization.

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Concrete

More Oversight Makes Cement Plants Less Safe

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Dijam Panigrahi makes a counterintuitive but data-backed argument that routing every sensor alert through human approval does not make cement plants safer.

India’s cement industry has spent the last two years wiring kilns, mills and coolers with sensors and automated control systems, and the safety case for doing so is strong on paper. Contract workers still make up the majority of the industry’s workforce, and fatal accidents remain a recurring problem. The Indian National Cement Workers Federation has noted that around 83 per cent of workers in the sector hold precarious positions, a fact that resurfaced after an oxygen cylinder explosion killed three contract workers at a plant in Chhattisgarh.
Industry tallies compiled by IndustriALL found cement plants recorded at least seventeen accidents in one year with 21 workers killed, and ten accidents the following year with nine killed, most of them contract staff. Automated monitoring, in theory, closes that gap. A sensor never gets complacent and never skips a check because a shift is short staffed.
However, plants that respond by routing every anomaly reading to a person for approval are quietly building a system that fails the same way understaffing does. When operators receive dozens of flagged deviations a shift, most of them minor, they learn a simple lesson: the fastest way through the queue is to approve without reading closely. The safety benefit disappears, not because the technology failed, but because the humans supervising it adapted to the volume.

Why alerts get ignored
A study cited by manufacturing technology publisher Applied SmartFactory found more than 95 per cent of alarms in a semiconductor fab were low priority, and only about 4 per cent ever triggered an action, with just 100 out of 5,000 alarms accounting for 70 per cent of all alarm activity. The mechanism is the same whether the trigger is a vibration sensor or an AI model flagging a kiln temperature swing. Once the ratio of noise to signal crosses a threshold, workers stop treating the system as a decision aid and start treating it as a formality to clear.
The scale of AI deployment underway makes this more than a theoretical risk. Stanford’s 2026 AI Index Report found organisational adoption of AI has reached 88 per cent, even as documented AI incidents rose to 362 in 2025, up sharply from 233 the year before, according to analysis of the report. The Index also found only about a third of organisations have adopted a formal governance framework, with NIST’s AI Risk Management Framework cited by 33 per cent and ISO/IEC 42001 cited by 36 per cent.
Most manufacturers are deploying monitoring systems faster than they are building the judgment for when a flagged event actually needs a person’s attention. In India, plants run by JK Cement have begun pairing CCTV feeds with AI to define safe zones around heavy machinery, a promising direction that still depends on operators trusting and reading the alerts the system generates.

A three-tier model for cement plant
The fix is not less monitoring or more monitoring. It is classifying decisions by risk and by novelty, rather than treating human oversight as a single switch that is either on or off. A workable model sorts factory floor events into three tiers.
The first tier, proceed, covers deviations the plant has seen before that fall within known safe bounds, such as a kiln feed rate adjustment within an established range. These should run without a stop for approval, because routing them to a person only trains that person to click through.
The second tier, pause, covers events that are unusual but not yet dangerous, such as a vibration reading trending toward a limit or a fuel blend shifting outside its typical mix. These warrant a brief human check before the system proceeds, giving an operator the chance to apply judgment the model does not yet have.
The third tier, escalate, covers events that are both high risk and unfamiliar, such as a pressure reading combined with a temperature spike that has no close precedent in the plant’s history. These should stop the process entirely and require a decision from someone with the authority to shut down a line.

Who should set the threshold
Where these tiers get drawn matters as much as the framework itself. Threshold setting is frequently handed to the vendor supplying the monitoring software or to a plant’s IT department, both of which understand the technology but not the specific tolerances of a given kiln, mill or line. Operations staff, who know that a particular grinding unit runs hotter under monsoon humidity or that a calciner behaves differently after a refractory reline, are better positioned to calibrate what counts as routine on their own equipment.
Handing threshold ownership to operations does not remove IT or vendors from the process, but it puts the calibration decision closest to the people who live with its consequences on the floor.

Signals that oversight is actually working
A few concrete indicators reveal whether a monitoring setup is functioning as intended or simply providing the appearance of safety. The escalation rate over time is the first: a rate that stays flat or climbs slowly as operations mature is healthy, while one that spikes and then falls sharply often means operators have started overriding the system rather than engaging with it. Time to resolution is the second: escalations that take progressively longer to close suggest fatigue or confusion about ownership, not diligence. The third, and most telling, is how accurate the system’s own uncertainty estimates turn out to be, meaning whether events flagged as high risk actually correlated with real incidents, and whether events waved through stayed incident free. A system whose escalations do not track with actual outcomes trains operators toward the same complacency that unmonitored equipment produces.
None of this argues against automation in Indian cement manufacturing, where a labor structure built on contract work and a track record of serious accidents make better monitoring an urgent need. It argues for treating human oversight as a design problem with three distinct settings, rather than a single
dial turned up whenever a plant wants to look safer on paper.

About the author:
Dijam Panigrahi, Co-founder and COO, GridRaster, is a spatial computing platform for industrial enterprises and manufacturers.

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Concrete

The biggest gap arises from inconsistent leadership

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Anuj Kumar Mathur, Safety Consultant, stresses on the importance of closing the enduring gap between what safety systems say on paper and what actually happens on the plant floor.

Robust safety manuals, certified PPE and digital monitoring systems mean little if the culture on the plant floor does not enforce them. Safety Consultant Anuj Kumar Mathur has spent enough time in high-risk operations to know precisely where that gap opens and why it persists. In this exclusive interaction, he suggests feasible ways to strengthen the safety culture at a manufacturing unit.

Having led safety across high-risk fuel operations, what lessons can the cement industry adopt to strengthen its safety culture beyond regulatory compliance?
Beyond regulatory compliance, the cement industry should embed visible leadership commitment, proactive risk assessment, process safety management, strong contractor control, near-miss learning, and employee engagement to build a resilient safety culture that prioritises prevention, operational discipline and continuous improvement over mere compliance.

As cement plants become increasingly automated and digitally connected, how should organisations redefine their approach to process safety and operational risk?
As cement plants become increasingly automated, organisations should integrate process safety with digital risk management by strengthening cybersecurity, real-time monitoring, predictive maintenance, management of change and workforce competency to ensure safe, reliable and resilient operations.

What are the most common gaps between having robust safety systems on paper and achieving consistent safety performance on the ground?
The biggest gap arises from inconsistent leadership commitment on ground, weak safety culture, inadequate supervision, poor risk communication, insufficient workforce engagement specially, ineffective training and failure to translate procedures into disciplined execution, accountability and continuous monitoring at the operational level.

How can cement manufacturers better integrate contractor safety, leadership accountability and workforce behaviour to build a truly zero-harm workplace?
Manufacturers can achieve a zero-harm workplace by enforcing uniform safety standards for employees and contractors, strengthening leadership accountability, promoting proactive hazard reporting, enhancing competency through continuous training and fostering a culture where safe behaviour is recognised, expected and consistently practiced

What emerging technologies and safety practices do you believe will have the greatest impact on risk prevention in cement manufacturing over the next decade?
Artificial intelligence, IoT-enabled monitoring, predictive analytics, digital twins, wearable safety devices, drones, robotics and advanced process automation will significantly enhance hazard detection, predictive maintenance, real-time risk management, and worker protection, enabling safer and more resilient cement manufacturing.
IoT-enabled monitoring is the use of interconnected sensors and smart devices to continuously collect, transmit and analyse real-time data from equipment, processes and the work environment. This enables early detection of unsafe conditions, equipment failures, or abnormal operating parameters, allowing timely intervention before incidents occur.
In cement manufacturing, IoT-enabled monitoring can be used for:
• Monitoring kiln, crusher, and mill temperatures, pressures, and vibrations.
• Detecting overheating of bearings and motors to prevent failures.
• Monitoring dust concentration, gas leaks (CO, SO2, NOx), and oxygen levels.
• Tracking conveyor belt alignment and condition.
• Monitoring structural health of silos and
storage facilities.
• Tracking worker location and exposure to hazardous environments using wearable devices.
• Providing real-time alerts and predictive maintenance recommendations.


Benefits:
• Early hazard detection
• Reduced equipment downtime
• Improved process safety and reliability
• Lower maintenance costs
• Enhanced regulatory compliance
• Better decision-making through real-time data and analytics
In simple terms, IoT-enabled monitoring transforms periodic manual inspections into continuous, real-time surveillance of plant safety and equipment health.

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