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Multiple headwinds to slow down cement cos earnings

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The earnings projections of cement companies for FY18 are likely to suffer amid lower antic-ipated sales volumes and subdued prices. According to dealer estimates, the all-India average cement price fell by 2 per cent sequentially to Rs 326 per 50 kg bag in the December 2017 quarter. On a year-on-year basis, it rose marginally by 5 per cent. Historically, the sector has been reporting better traction in December. However, this time, realisation is under pressure due to several headwinds.

For instance, cost of sand, a key raw material, has increased by 4-5 times from the year ago due to lesser availability. In addition, construction activities in the real estate segment have slowed following demonetisation and implementation of Real Estate Regulatory Authority (RERA) Bill. The segment accounts for 60-65 per cent of total cement consumption. This has impacted offtake volume.

According to analysts, meeting the earlier expectation of 7-8 per cent volume growth for the full year will be a difficult task. To deliver that much growth, companies would require to clock 9 per cent growth in the second half of the fiscal.

Pet coke duty hike to hit operating margins
Cement companies operating profits may fall by one per cent following the Government’s decision to hike import duty on pet coke to 10 percent from the current 2.5 percent, a report said. ‘The operating margins of cement companies, which use high proportion of pet coke are likely to be affected following the government’s decision to increase the import duty on pet coke to 10 per cent from the present 2.5 per cent. The operating margins of cement manufacturers may fall by about 1 per cent, if increased cost is not passed on to end users,’ India Ratings said in its report.

The increase in import duty was announced after the Supreme Court decided to lift the ban on the use of pet coke. The Supreme Court allowed the cement industry to use pet coke as a feedstock, which had been banned last month to clean up the air pollution. While, issuing the exemption order for cement units, the apex court asked the government to frame guidelines for the use of pet coke.

Ind-Ra said that the cement manufacturers may resort to coal imports due to low domestic availability. Cement manufacturers prefer using pet coke, as it contains high calorific value (7,500-8, 500 Kcal/kg), to non-coking coal (2,200-7,000 Kcal/kg). The rise in the import duty on pet coke will result in a rise in power and fuel cost per metric tonne to Rs 5-7 per bag.

Total pet coke consumption in India increased by 34 per cent in October 2017 to 2 million metric tonne as compared with the level recorded for October 2015. Of the total pet coke consumed in the country during FY17-1HFY18, about 50 per cent was sourced domestically and the remaining through imports. According to Ind-Ra’s assessment, 35 per cent of the total pet coke imports were consumed by the cement industry.

Cement prices set to increase
Cement prices in India are expected to increase by Rs 3-4/bag by mid-January as the government has decided to hike the import duty on pet coke from the current 2.5 to 10 per cent. The rise in duty is expected to increase production costs by Rs 50-60/t and sector analysts predict the increase will be passed on to customers. ‘In case they are not passing it on, their EBITDA is likely to get affected and under the current scenario, no company will wish for it,’ an analyst with stockbroking firm Motilal Oswal Financial Services told. While the price of pet coke is currently 10-12 per cent higher than that of imported coal, its lower volume requirement means it is more cost-effective for cement producers to use.

Dalmia Bharat to acquire Murli Industries
Cement manufacturer Dalmia Bharat said its Rs 402 crore bid to acquire Murli Industries Ltd (MIL) has been approved by the Committee of Creditors (CoC) of the Nagpur-based company. The resolution plan submitted by Dalmia Cement (Bharat) Ltd, a subsidiary of Dalmia Bharat, to CoC of MMIL under the Insolvency and Bankruptcy Code, 2016 was approved recently.

‘Committee of creditors of MIL on December 20, 2017 approved the proposed resolution plan submitted by our subsidiary, DCBL for recommendation to NCLT Mumbai for its approval in relation to revival of MIL,’the company said.

It further added:
‘Following receipt of requisite approvals, the resolution plan provides for a payment of Rs 402 crore which is 1.7 times higher than the determined liquidation value.’

MIL has an integrated cement manufacturing plant with installed capacity of 3 MTPA in Chandrapur district of Maharashtra along with a captive thermal power plant of 50 MW. In addition, MIL also has paper and solvent extraction units in Maharashtra. MIL was referred to the corporate insolvency process by its lenders in April 2017. It had interests in cement, paper, solvent, power and pulp.

Coal shortage hits thermal power plants
Thermal power plants across India are facing a shortage of coal. If this situation does not improve over the next the few days, there is a real threat that power generated may stop. About 600 MW of coal-based power generation is already affected due to the coal shortage. The Western and Northern regions are the most affected, and in States such as Maharashtra and Rajasthan, about 40 per cent of power generated from coal is affected.

According to data of the Central Electricity Authority (CEA), most thermal power plants have just one to three days of reserve coal stock. Sources in Singareni Collieries say thermal plants to which it supplies coal are not facing any shortage of coal. These include plants in Telangana and Andhra Pradesh. According to CEA data, the number of thermal power plants in the country with critical stock (for only seven days) is four. The number of thermal power plants with super critical stock (for only four days) is 23.

CEA said that plants having low stocks due to outstanding dues, supply being more than committed quantity, and not lifting offered coal, are not listed in the critical and super critical data. In Andhra Pradesh, the Rayalaseema Thermal Power Station (RTPS) has coal stock for only four days, the Simhadri thermal power station has coal stock for two more days and Vizag thermal power plant has coal stock for three days. In Telangana, Ramagundam thermal power plant has coal stock for three days and Kakatiya and Kothagudem thermal power plants have coal stock for 10-21 days. There are nine plants in the northern region and 12 plants in the western region that are in critical and super critical stages.

The Union power ministry says that the issue of coal supply to power plants is being addressed in a coordinated manner by the three concerned ministries – power, coal and Railways. The Power Ministry said that this is being monitored at the highest level and that in spite of the the unprecedented rise in the demand for coal based power, due to better coordinated planning the demand of electricity in the grid is being met. More than 65 per cent of India’s electricity generation capacity comes from thermal power plants, with about 85 per cent of the country’s thermal power generation being coal-based.

The 10 biggest thermal power stations operating in India are all coal-fired.

SC allows use of pet coke in cement
The Supreme Court allowed the cement industry to use petroleum coke, a dirtier alternative to coal which had temporarily been banned as pollution levels shot up in Delhi last month. India is the world’s biggest consumer of petroleum coke, better known as pet coke, a dark solid carbon material that emits 11 per cent more greenhouse gas than coal, according to studies.

The Supreme Court in October banned the use of pet coke in and around New Delhi in a bid to clean the air in one of the world’s most polluted cities. But a blanket ban on the sale and use of petcoke could hit the country’s small and medium scale industries, which employ millions of workers and operate on thin margins, businesses say.

Supreme Court Judge Madan Bhimrao Lokur, in issuing the exemption order for cement and limestone industries, asked the government to frame guidelines for the use of pet coke. Shares of Indian cement companies, which use pet coke as feedstock, surged as much as 5 per cent on news of the court decision. Local producers of pet coke include Indian Oil Corp, Reliance Industries and Bharat Petroleum Corp.

Cement prices firm up in South
Prices of cement have jumped by an average Rs 25-30 per bag in the Southern States. The price is now hovering around Rs 310-320 per bag in Andhra Pradesh and Telangana. In Karnataka, its around Rs 340, while in Tamil Nadu and Kerala, it is being sold at over Rs 360. The prices were in the range of Rs 280 in Andhra Pradesh and Telangana. The present increase has not been normal, says M Prasad, a wholesale dealer of leading cement brands here. ‘Normally prices go up as the construction activity picks up during February to July for the year, which is seen as the best season for price realisation,’ he added.

Interestingly, the summer of 2017 proved different to the earlier three-four summers as prices unusually fell to around Rs 270 in Andhra Pradesh and Telangana. Typically, the prices are at peak with demand picking up and construction activity in full swing.

There has been no change in other factors such as production capacity and demand. Still the capacity utilisation and demand are under 40 per cent. The second quarter had seen a price erosion.

As per industry data, prices from August, September to October show that price erosion was in the range of Rs 5 in Andhra Pradesh and Telangana markets.

In Bengaluru, the prices remained more or less stable. Chennai also saw a drop of another Rs 5-10. In the days to come, the expected volume growth in the industry could be varied.

In Andhra Pradesh, the non-grounding of works related to the new capital Amaravati did not give the anticipated boost to the industry. The industry is hoping to gain from new capital probably a year and year-and-a-half from now in a slow fashion to be ramped up later. Even in Telangana, the real estate sector in the capital Hyderabad, is seeing ups and downs as far as new projects are concerned.

Cement, steel at the core of strongest infra show in a year
India’s infrastructure sector logged the highest growth in more than a year in November, while the country’s biggest carmakers reported double-digit sales growth in December, kicking off the new year on a positive note for the economy and pointing to a persistent revival trend. The index of eight core industries rose 6.8 per cent in November, the Government data showed, riding high on growth in cement and steel sectors. These have a weight of more than 40 per cent in the Index of Industrial Production (IIP), suggesting strong industrial growth in November after a dismal October.

‘Steel and cement growth at very high growth rates of 16.6 per cent and 17.3 per cent indicates restoration of the production in these sectors over pre-demonetisation levels which augurs well for real sector investment,’ said Economic Affairs Secretary, Subhash Chandra Garg.

Part of the rise is due to the favourable base effect stemming from the disruption in the wake of demonetisation in November 2016 that will prevail over the next few months.

The core sector grew 3.6 per cent in November 2016. The core sector growth in November 2017 was the best since 7.1 per cent in October 2016.

‘The early indicators for industrial production in the organised sectors in November 2017 provide favourable signals, such as the uptick in growth of the core sector and sharp improvement in the expansion of automobile production and non-oil merchandise exports,’ said Aditi Nayar, Principal Economist, ICRA.

India’s GDP growth recovered to 6.3 per cent in the July-September period from a three-year low of 5.7 per cent in the preceding quarter. Most experts had expected a stronger rebound as the impact of demonetisation and rollout of GST in July had faded.

CIL assures captive power producers of coal supply
State-owned miner Coal India (CIL) has assured coal availability to power industry body ICPPA, whose members include firms from steel and aluminium segment, as they are heavily dependent on the dry fuel. CIL Chairman and MD Gopal Singh along with other senior officials held a meeting with members of Indian Captive Power Producers Association (ICPPA). In India, captive power producers’ capacity stands at 40,000 Mega Watts (MW) and about 30,000 MW is produced by using coal, which is about 75 per cent. The rest is produced through alternate materials like gas-based and others, ICPPA General Secretary Rajiv Agarwal told.

‘The industry is highly dependent on coal and the government must understand this. There are many plants who are on the verge of shut down. Many may become a non-performing asset (NPA),’ he said. CIL, in the meeting, said about 71 per cent materialisation of coal was done during April-December 2017 for both IPPs (integrated power producers) and CPPs and assured there is no shortage of coal.

ICPPA said it is not satisfied by the words of the PSU, who it said is supposed to supply the dry fuel to industry. Agarwal said, ‘The given figure included dispatches by both rail and road. The share of CPPs rail dispatches is in the range of only 30 to 50 per cent and out of this 30 per cent major supply was given to those plants who were near the pits.’

Even if coal linkage auction is concerned, 41.5 MT was offered to the CPPs, he said and added, that out this the industry could not bid for 8.5 MT offered at ‘Magad-Amrapali of CCL (Central Coalfields Ltd)’ a place with evacuation constraint.

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Concrete

Refractory demands in our kiln have changed

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Radha Singh, Senior Manager (P&Q), Shree Digvijay Cement, points out why performance, predictability and life-cycle value now matter more than routine replacement in cement kilns.

As Indian cement plants push for higher throughput, increased alternative fuel usage and tighter shutdown cycles, refractory performance in kilns and pyro-processing systems is under growing pressure. In this interview, Radha Singh, Senior Manager (P&Q), Shree Digvijay Cement, shares how refractory demands have evolved on the ground and how smarter digital monitoring is improving kiln stability, uptime and clinker quality.

How have refractory demands changed in your kiln and pyro-processing line over the last five years?
Over the last five years, refractory demands in our kiln and pyro line have changed. Earlier, the focus was mostly on standard grades and routine shutdown-based replacement. But now, because of higher production loads, more alternative fuels and raw materials (AFR) usage and greater temperature variation, the expectation from refractory has increased.
In our own case, the current kiln refractory has already completed around 1.5 years, which itself shows how much more we now rely on materials that can handle thermal shock, alkali attack and coating fluctuations. We have moved towards more stable, high-performance linings so that we don’t have to enter the kiln frequently for repairs.
Overall, the shift has been from just ‘installation and run’ to selecting refractories that give longer life, better coating behaviour and more predictable performance under tougher operating conditions.

What are the biggest refractory challenges in the preheater, calciner and cooler zones?
• Preheater: Coating instability, chloride/sulphur cycles and brick erosion.
• Calciner: AFR firing, thermal shock and alkali infiltration.
• Cooler: Severe abrasion, red-river formation and mechanical stress on linings.
Overall, the biggest challenge is maintaining lining stability under highly variable operating conditions.

How do you evaluate and select refractory partners for long-term performance?
In real plant conditions, we don’t select a refractory partner just by looking at price. First, we see their past performance in similar kilns and whether their material has actually survived our operating conditions. We also check how strong their technical support is during shutdowns, because installation quality matters as much as the material itself.
Another key point is how quickly they respond during breakdowns or hot spots. A good partner should be available on short notice. We also look at their failure analysis capability, whether they can explain why a lining failed and suggest improvements.
On top of this, we review the life they delivered in the last few campaigns, their supply reliability and their willingness to offer plant-specific custom solutions instead of generic grades. Only a partner who supports us throughout the life cycle, which includes selection, installation, monitoring and post-failure analysis, fits our long-term requirement.

Can you share a recent example where better refractory selection improved uptime or clinker quality?
Recently, we upgraded to a high-abrasion basic brick at the kiln outlet. Earlier we had frequent chipping and coating loss. With the new lining, thermal stability improved and the coating became much more stable. As a result, our shutdown interval increased and clinker quality remained more consistent. It had a direct impact on our uptime.

How is increased AFR use affecting refractory behaviour?
Increased AFR use is definitely putting more stress on the refractory. The biggest issue we see daily is the rise in chlorine, alkalis and volatiles, which directly attack the lining, especially in the calciner and kiln inlet. AFR firing is also not as stable as conventional fuel, so we face frequent temperature fluctuations, which cause more thermal shock and small cracks in the lining.
Another real problem is coating instability. Some days the coating builds too fast, other days it suddenly drops, and both conditions impact refractory life. We also notice more dust circulation and buildup inside the calciner whenever the AFR mix changes, which again increases erosion.
Because of these practical issues, we have started relying more on alkali-resistant, low-porosity and better thermal shock–resistant materials to handle the additional stress coming from AFR.

What role does digital monitoring or thermal profiling play in your refractory strategy?
Digital tools like kiln shell scanners, IR imaging and thermal profiling help us detect weakening areas much earlier. This reduces unplanned shutdowns, helps identify hotspots accurately and allows us to replace only the critical sections. Overall, our maintenance has shifted from reactive to predictive, improving lining life significantly.

How do you balance cost, durability and installation speed during refractory shutdowns?
We focus on three points:
• Material quality that suits our thermal profile and chemistry.
• Installation speed, in fast turnarounds, we prefer monolithic.
• Life-cycle cost—the cheapest material is not the most economical. We look at durability, future downtime and total cost of ownership.
This balance ensures reliable performance without unnecessary expenditure.

What refractory or pyro-processing innovations could transform Indian cement operations?
Some promising developments include:
• High-performance, low-porosity and nano-bonded refractories
• Precast modular linings to drastically reduce shutdown time
• AI-driven kiln thermal analytics
• Advanced coating management solutions
• More AFR-compatible refractory mixes

These innovations can significantly improve kiln stability, efficiency and maintenance planning across the industry.

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Concrete

Digital supply chain visibility is critical

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MSR Kali Prasad, Chief Digital and Information Officer, Shree Cement, discusses how data, discipline and scale are turning Industry 4.0 into everyday business reality.

Over the past five years, digitalisation in Indian cement manufacturing has moved decisively beyond experimentation. Today, it is a strategic lever for cost control, operational resilience and sustainability. In this interview, MSR Kali Prasad, Chief Digital and Information Officer, Shree Cement, explains how integrated digital foundations, advanced analytics and real-time visibility are helping deliver measurable business outcomes.

How has digitalisation moved from pilot projects to core strategy in Indian cement manufacturing over the past five years?
Digitalisation in Indian cement has evolved from isolated pilot initiatives into a core business strategy because outcomes are now measurable, repeatable and scalable. The key shift has been the move away from standalone solutions toward an integrated digital foundation built on standardised processes, governed data and enterprise platforms that can be deployed consistently across plants and functions.
At Shree Cement, this transition has been very pragmatic. The early phase focused on visibility through dashboards, reporting, and digitisation of critical workflows. Over time, this has progressed into enterprise-level analytics and decision support across manufacturing and the supply chain,
with clear outcomes in cost optimisation, margin protection and revenue improvement through enhanced customer experience.
Equally important, digital is no longer the responsibility of a single function. It is embedded into day-to-day operations across planning, production, maintenance, despatch and customer servicing, supported by enterprise systems, Industrial Internet of Things (IIoT) data platforms, and a structured approach to change management.

Which digital interventions are delivering the highest ROI across mining, production and logistics today?
In a capital- and cost-intensive sector like cement, the highest returns come from digital interventions that directly reduce unit costs or unlock latent capacity without significant capex.
Supply chain and planning (advanced analytics): Tools for demand forecasting, S&OP, network optimisation and scheduling deliver strong returns by lowering logistics costs, improving service levels, and aligning production with demand in a fragmented and regionally diverse market.
Mining (fleet and productivity analytics): Data-led mine planning, fleet analytics, despatch discipline, and idle-time reduction improve fuel efficiency and equipment utilisation, generating meaningful savings in a cost-heavy operation.
Manufacturing (APC and process analytics): Advanced Process Control, mill optimisation, and variability reduction improve thermal and electrical efficiency, stabilise quality and reduce rework and unplanned stoppages.
Customer experience and revenue enablement (digital platforms): Dealer and retailer apps, order visibility and digitally enabled technical services improve ease of doing business and responsiveness. We are also empowering channel partners with transparent, real-time information on schemes, including eligibility, utilisation status and actionable recommendations, which improves channel satisfaction and market execution while supporting revenue growth.
Overall, while Artificial Intelligence (AI) and IIoT are powerful enablers, it is advanced analytics anchored in strong processes that typically delivers the fastest and most reliable ROI.

How is real-time data helping plants shift from reactive maintenance to predictive and prescriptive operations?
Real-time and near real-time data is driving a more proactive and disciplined maintenance culture, beginning with visibility and progressively moving toward prediction and prescription.
At Shree Cement, we have implemented a robust SAP Plant Maintenance framework to standardise maintenance workflows. This is complemented by IIoT-driven condition monitoring, ensuring consistent capture of equipment health indicators such as vibration, temperature, load, operating patterns and alarms.
Real-time visibility enables early detection of abnormal conditions, allowing teams to intervene before failures occur. As data quality improves and failure histories become structured, predictive models can anticipate likely failure modes and recommend timely interventions, improving MTBF and reducing downtime. Over time, these insights will evolve into prescriptive actions, including spares readiness, maintenance scheduling, and operating parameter adjustments, enabling reliability optimisation with minimal disruption.
A critical success factor is adoption. Predictive insights deliver value only when they are embedded into daily workflows, roles and accountability structures. Without this, they remain insights without action.

In a cost-sensitive market like India, how do cement companies balance digital investment with price competitiveness?
In India’s intensely competitive cement market, digital investments must be tightly linked to tangible business outcomes, particularly cost reduction, service improvement, and faster decision-making.
This balance is achieved by prioritising high-impact use cases such as planning efficiency, logistics optimisation, asset reliability, and process stability, all of which typically deliver quick payback. Equally important is building scalable and governed digital foundations that reduce the marginal cost of rolling out new use cases across plants.
Digitally enabled order management, live despatch visibility, and channel partner platforms also improve customer centricity while controlling cost-to-serve, allowing service levels to improve without proportionate increases in headcount or overheads.
In essence, the most effective digital investments do not add cost. They protect margins by reducing variability, improving planning accuracy, and strengthening execution discipline.

How is digitalisation enabling measurable reductions in energy consumption, emissions, and overall carbon footprint?
Digitalisation plays a pivotal role in improving energy efficiency, reducing emissions and lowering overall carbon intensity.
Real-time monitoring and analytics enable near real-time tracking of energy consumption and critical operating parameters, allowing inefficiencies to be identified quickly and corrective actions to be implemented. Centralised data consolidation across plants enables benchmarking, accelerates best-practice adoption, and drives consistent improvements in energy performance.
Improved asset reliability through predictive maintenance reduces unplanned downtime and process instability, directly lowering energy losses. Digital platforms also support more effective planning and control of renewable energy sources and waste heat recovery systems, reducing dependence on fossil fuels.
Most importantly, digitalisation enables sustainability progress to be tracked with greater accuracy and consistency, supporting long-term ESG commitments.

What role does digital supply chain visibility play in managing demand volatility and regional market dynamics in India?
Digital supply chain visibility is critical in India, where demand is highly regional, seasonality is pronounced, and logistics constraints can shift rapidly.
At Shree Cement, planning operates across multiple horizons. Annual planning focuses on capacity, network footprint and medium-term demand. Monthly S&OP aligns demand, production and logistics, while daily scheduling drives execution-level decisions on despatch, sourcing and prioritisation.
As digital maturity increases, this structure is being augmented by central command-and-control capabilities that manage exceptions such as plant constraints, demand spikes, route disruptions and order prioritisation. Planning is also shifting from aggregated averages to granular, cost-to-serve and exception-based decision-making, improving responsiveness, lowering logistics costs and strengthening service reliability.

How prepared is the current workforce for Industry 4.0, and what reskilling strategies are proving most effective?
Workforce preparedness for Industry 4.0 is improving, though the primary challenge lies in scaling capabilities consistently across diverse roles.
The most effective approach is to define capability requirements by role and tailor enablement accordingly. Senior leadership focuses on digital literacy for governance, investment prioritisation, and value tracking. Middle management is enabled to use analytics for execution discipline and adoption. Frontline sales and service teams benefit from
mobile-first tools and KPI-driven workflows, while shop-floor and plant teams focus on data-driven operations, APC usage, maintenance discipline, safety and quality routines.
Personalised, role-based learning paths, supported by on-ground champions and a clear articulation of practical benefits, drive adoption far more effectively than generic training programmes.

Which emerging digital technologies will fundamentally reshape cement manufacturing in the next decade?
AI and GenAI are expected to have the most significant impact, particularly when combined with connected operations and disciplined processes.
Key technologies likely to reshape the sector include GenAI and agentic AI for faster root-cause analysis, knowledge access, and standardisation of best practices; industrial foundation models that learn patterns across large sensor datasets; digital twins that allow simulation of process changes before implementation; and increasingly autonomous control systems that integrate sensors, AI, and APC to maintain stability with minimal manual intervention.
Over time, this will enable more centralised monitoring and management of plant operations, supported by strong processes, training and capability-building.

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Concrete

Cement Additives for Improved Grinding Efficiency

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Shreesh A Khadilkar discusses how advanced additive formulations allow customised, high-performance and niche cements—offering benefits while supporting blended cements and long-term cost and carbon reduction.

Cement additives are chemicals (inorganic and organic) added in small amounts (0.01 per cent to 0.2 per cent by weight) during cement grinding. Their main job? Reduce agglomeration, prevent pack-set, and keep the mill running smoother. Thus, these additions primarily improve, mill thru-puts, achieve lower clinker factor in blended cements PPC/PSC/PCC. Additionally, these additives improve concrete performance of cements or even for specific special premium cements with special USPs like lower setting times or for reduced water permeability in the resultant cement mortars and concrete (water repellent /permeation resistant cements), corrosion resistance etc.
The cement additives are materials which could be further differentiated as:

Grinding aids:
• Bottlenecks in cement grinding capacity, such materials can enhance throughputs
• Low specific electrical energy consumption during cement grinding
• Reduce “Pack set” problem and improve powder flowability

Quality improvers:
• Opportunity for further clinker factor reduction
• Solution for delayed cement setting or strength development issues at early or later ages.

Others: materials which are used for specific special cements with niche properties as discussed in the subsequent pages.
When cement additives are used as grinding aids or quality improvers, in general the additives reduce the inter-particle forces; reduce coating over grinding media and mill internals. Due to creation of like charges on cement particles, there is decreased agglomeration, much improved flowability, higher generation of fines better dispersion of particles in separator feed and reduction of mill filling level (decrease of residence time). However, in VRM grinding; actions need to be taken to have stable bed formation on the table.
It has been reported in literature and also substantiated by a number of detailed evaluations of different cement additive formulations in market, that the cement additive formulations are a combination of different chemical compounds, typically composed of:

  1. Accelerator/s for the hydration reaction of cements which are dependent on the acceleration effect desired in mortar compressive strengths at early or later ages, the choice of the materials is also dependent on clinker quality and blending components (flyash / slag) or a mix of both.
  2. Water reducer / workability / wet-ability enhancer, which would show impact on the resultant cement mortars and concrete. Some of the compounds (retarders) like polysaccharide derivatives, gluconates etc., show an initial retarding action towards hydration which result in reducing the water requirements for the cements thus act as water reducers, or it could be some appropriate polymeric molecules which show improved wet-ability and reduce water demand. These are selected based on the mineral component and type of cements (PPC/PSC /PCC).
  3. Grinding aids: Compounds that work as Grinding Aid i.e. which would enhance Mill thru-put on one hand as well as would increase the early strengths due to the higher fines generation/ or activation of cement components. These compounds could be like alkanol-amines such as TIPA, DEIPA, TEA etc. or could be compounds like glycols and other poly-ols, depending on whether it is OPC or PPC or PSC or PCC manufacture.

Mechanism of action — Step By Step—

  1. Reduce Agglomeration, Cement particles get electrostatically charged during grinding, stick together, form “flocs”, block mill efficiency, waste energy. Grinding aid molecules adsorb onto particle surfaces, neutralise charge, prevent re-agglomeration.
  2. Improve Powder Flowability, Adsorbed molecules create a lubricating layer, particles slide past each other easier, better mill throughput, less “dead zone” buildup.
    Also reduces caking on mill liners, diaphragms, and separator screens, less downtime for cleaning.
  3. Enhance Grinding Efficiency (Finer Product Faster), By preventing agglomeration, particles stay dispersed more surface area exposed to grinding media, finer grind achieved with same energy input, Or: same fineness achieved with less energy, huge savings.
    Example:
    • Without aid ? 3500 cm²/g Blaine needs 40 kWh/ton
    • With use of optimum grinding aid same fineness at 32 kWh/ton 20 per cent energy savings
  4. Reduce Pack Set and Silo Caking Grinding aids (GA) inhibit hydration of free lime (CaO) during storage prevents premature hardening or “pack set” in silos. especially critical in humid climates or with high free lime clinker.
    It may be stated here that Overdosing of GA can cause: – Foaming in mill (especially with glycols) reduces grinding efficiency, retardation of cement setting (especially with amines/acids), odor issues (in indoor mills) – Corrosion of mill components (if acidic aids used improperly)
    The best practice to optimise use of GA is Start with 0.02 per cent to 0.05 per cent dosage test fineness, flow, and set time adjust up/down. Due to static charge of particles, the sample may stick to the sides of sampler pipe and so sampling need to be properly done.
    Depending on type of cements i.e. OPC, PPC, PSC, PCC, the grinding aids combinations need to be optimised, a typical Poly carboxylate ether also could be a part of the combo grinding aids

Cement additives for niche properties of the cement in concrete.
The cement additives can also be tailor made to create specific niche properties in cements, OPC, PPC, PSC and PCC to create premium or special brands. The special niche properties of the cement being its additional USP of such cement products, and are useful for customers to build a durable concrete structure with increased service life.


Such properties could be:
• Additives for improved concrete performance of cements, high early strength in PPC/PSC/PCC, much reduced water demand in cement, cements with improved slump retentivity in concrete, self-compacting, self levelling in concrete, cements with improved adhesion property of the cement mortar
• Water repellence / water proofing, permeability resistance in mortars and concrete.
• Biocidal cement
• Photo catalytic cements
• Cements with negligible ASR reactions etc.

Additives for cements for improved concrete performance
High early strengths: Use of accelerators. These are chemical compounds which enhance the degree of hydration of cement. These can include setting or hardening accelerators depending on whether their action occurs in the plastic or hardened state respectively. Thus, the setting accelerators reduce the setting time, whereas the hardening accelerators increase the early age strengths. The setting accelerators act during the initial minutes of the cement hydration, whereas the hardening accelerators act mainly during the initial days of hydration.
Chloride salts are the best in class. However, use of chloride salts as hardening accelerators are strongly discouraged for their action in promoting the corrosion of rebar, thus, chloride-free accelerators are preferred. The hardening accelerators could be combinations of compounds like nitrate, nitrite and thiocyanate salts of alkali or alkaline earth metals or thiosulphate, formate, and alkanol amines depending on the cement types.
However, especially in blended cements (PPC/PSC/PCC the increased early strengths invariably decrease the 28 day strengths. These aspects lead to creating combo additives along with organic polymers to achieve improved early strengths as well as either same or marginally improved 28 days strengths with reduced clinker factor in the blended cement, special OPC with reduced admixture requirements. With use of appropriate combination of inorganic and organic additives we could create an OPC with substantially reduced water demand or improved slump retentivity. Use of such an OPC would show exceptional concrete performance in high grade concretes as it would exhibit lower admixture requirements in High Grade Concretes.
PPC with OPC like properties: With the above concept we could have a PPC, having higher percentage flyash, with a combo cement additive which would have with concrete performance similar to OPC in say M40/M50 concrete. Such a PPC would produce a high-strength PPC concrete (= 60 MPa @ 28d) + improved workability, durability and sustainability.
Another interesting aspect could also be of using ultrafine fine flyash /ultrafine slags as additions in OPC/PPC/PSC for achieving lower clinker factor as well as to achieve improved later age strengths with or without a combo cement additive.
The initial adhesion property at sites of especially PPC/PSC/PCC based mortars can be improved through use of appropriate organic polymers addition during the manufacture of these cements. Such cements would have a better adhesion property for plastering/brick bonding etc., as it has much lower rebound loss of their mortars in such applications.
It is needless to mention here that with use of additives, we could also have cement with viscosity modifying cement additives, for self-compaction and self-leveling concrete performance.
Use of Phosphogypsum retards the setting time of cements, we can use additive different additive combos to overcome retardation and improve the 1 day strengths of the cements and concretes.

About the author:
Shreesh Khadilkar, Consultant & Advisor, Former Director Quality & Product Development, ACC, a seasoned consultant and advisor, brings over 37 years of experience in cement manufacturing, having held leadership roles in R&D and product development at ACC Ltd. With deep expertise in innovative cement concepts, he is dedicated to sharing his knowledge and improving the performance of cement plants globally.

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