Economy & Market
An Eco-Friendly Option
Published
8 years agoon
By
admin
Today’s blended cements have its origin in the old Roman construction. Due to technological advancements [now] the similar cements are available in the new forms.
The Romans started making concrete more than 2,000 years ago, but it wasn’t quite like today’s concrete. They had a different formula, which resulted in a substance that was not as strong as the modern product. ‘Roman concrete is . . . considerably weaker than modern concretes. It’s approximately ten times weaker,’ says Renato Perucchio, a mechanical engineer at the University of Rochester in New York. ‘What this material is assumed to have is phenomenal resistance over time.’ That resistance, or durability against the elements, may be due to one of the concrete’s key ingredients: volcanic ash. Modern concrete is a mix of a lime-based cement, water, sand and so-called aggregates such as fine gravel.
Indian scenario
Surkhi, was the commonest pozzolanic materials used in India resembles volcanic ash. It has been used along with lime in many of our old structures, before modern Portland cement has taken its roots in India. Even after Portland cement made its appearance in the field of construction, Surkhi was used as an admixture to remedy some of the shortcomings of cement concrete. Surkhi was one of the main constituents in waterproofing treatments in conjunction with lime and sometimes even with cement for extending valuable pozzolanic action to make the treatment impervious. Surkhi is an artificial pozzolana made by powdering bricks or burnt clay balls. In some major works, for large scale production of Surkhi, clay balls are specially burnt for this purpose and then powdered. By its nature, it is a very complex material differing widely in its qualities and performances. Bhakra Nangal Dam is a standing ovation to the use of Surkhi in the construction.
Policy hurdles
The Indian cement sector had been under strict government control for almost the whole of the period 1969 to 1982. Government intervention took place both directly and indirectly. Direct intervention happened in the form of government control over production, capacity and distribution of cement, while indirect intervention took the form of price control. During this period, many companies and their plants started off but still growth was not seen at the desired rate. In 1977, higher prices were allowed for cement produced by new plants or major expansions of existing plants. Due to slow development, the uniform price imposed by the government, was substituted by a three-tier price system in 1979. Different prices were assigned to cement produced in low, medium and high cost plants.
Later on during the shortage of cement the producers were allowed to use Surkhi, burnt clay as a pozzolanic material to produce more quantity of cement and then the problem of quality started. Indiscriminate use of any sort of burnt clay material, without ensuring proper quality control norms created many issues with Pozzolana cement and gave it a bad name in late seventies and early eighties. Therefore initially when blended cements were reintroduced based on fly ash as a performance enhancer had to face users resistance. Now the blended cement available based with fly ash as a pozzolana is much different than the Surkhi-based Pozzolana cement.
Present scene
As per the papers published by NCCBM, the production of ordinary Portland Cement in India has currently remained to about 25 per cent and that of Portland Pozzolana cement has steadily increased to about 67 per cent. The production of Portland slag cement is limited to 8 per cent. The production trend of different types of cement such as OPC, PPC, PSC and others in the last decade indicates that the trend is more towards blended cements. This is a favourable change in the product mix of Indian cement industry as PPC and PSC are more specialised types of cement with advantages in terms of better durability characteristics.
Many developed countries started using such blended cements in large quantities in construction of critical structures such as rocket launch pads, sea water jetties, huge dams, etc. Production of blended cements directly increases the plant capacity without any need for creating additional clinker making capacity. In an environment of growing competition, another development has been the introduction of higher grades of cement particularly for OPC. However, realisation is growing fast amongst the consumers at large, that the properties of durability are of greater importance than strength.
Improvement in construction technologies and the need for durable construction in different aggressive environments have enhanced the use of blended cements. Under such prevailing trend the need of stringent control on quality parameters related to raw materials and cement becomes essential. In the present paper, efforts have been made to present quality trends of OPC and PPC as their production is around 92 per cent of total. In order to conserve high grade limestone and fuels, thrust is given for the production of variety of cements using inferior grade and/or alternative raw materials by adopting state-of-art manufacturing technology. To maintain the quality of cements and to promote the use of different types of wastes/by-products or inferior grade raw materials in the cement manufacture, BIS (Bureau of Indian Standards) has incorporated amendments in the standard specifications and also revised some of the specifications. The salient features of the modifications in standards are:
- Increase in limit of pozzolana in PPC
- Increase in limit of granulated blast furnace slag in PSC
- Increase in limit of MgO in PSC
- Specifying the upper limit of compressive strength at 672 ? 4 hrs for OPC-33 & 43 grades
- Addition of performance improver up to 5 per cent in OPC
- Enhancing the limits of insoluble residue
- Increasing the limits of SO3 to 3.5 per cent Specifying requirements of cement for pre-cast concrete
Most of the cement plants in India have the state-of-the-art technology and are able to achieve their capacity utilisation as per the market demand. Cement industry is going ahead with a modification and upgradation of technology particularly in energy conservation. Cement industry’s average energy consumption is about 725 kcal/kg clinker thermal energy and 80 kWh/t cement electrical energy.
Efforts are on relating to utilisation of alternate energy sources/fuels either partially or fully substitute coal in cement manufacture in the coming years, namely, pet coke, lignite, natural gas, and biomass wastes including fruit of Jatropha Carcus, Pongamia and Algae. Although the modern cement plants have incorporated the latest technology, yet there is scope for further improvement in the areas of coprocessing of waste derived/hazardous combustible wastes as fuel, cogeneration of power, bulk transport of cement, palletising and shrink wrapping for packing and dispatch.
Future trends
The R&D activities and thrust to reduce CO2 emission associated with properties has resulted a trend towards the increased use of blended cement with the share of blended cements increasing to 75 per cent followed by Ordinary Portland Cement (OPC) (? 25 per cent). Fly ash based Portland Pozzolana Cement (PPC) contributes the major share (67 per cent) of the total production with 8 per cent of Portland Slag Cement (PSC). In addition to conservation of natural resources, fuel and reduction of green house gases, there are other advantages of using blended cements.
The cement industry in India has also shown potential to utilise hazardous waste. The awareness on utilisation of wastes and environmental pollutants in the manufacture of cement have increased many folds in the last decade. The production of PPC and PSC of uniform quality by utilising more proportion of fly ash and/or slag could be possible by their assured consumer acceptance and research activities.
By and large (BIS) Indian specifications have kept pace with the specifications from developed countries and have been quite dynamic with times and technology. The amendments in the specification are expected to come in the shortest possible of times, which is rather difficult for such a large country. Recently BIS has come out with codes for composite cement which allows the use of two different SCMs like fly ash and slag together. It is one step forward. There is a need for standard specifications for composite cements, using variety of wastes and keeping in view the pragmatic approach of utilisation of cement in different types of construction activities has also been realised.
Various wastes like lead-zinc slag, copper slag, steel slag, marble dust, which were not allowed for utilisation earlier, have now been identified as suitable material for the use in cement and other building products. As availability of coal and limestone are limited and soon these will be finished and on the other hand the requirement for cement is ever increasing. Hence adopting modern technologies and alternate materials is very essential for cement industry to meet this gap.
Cenospheres are one of the most desired by products of fly ash. They are small hollow spheres with roughly 10-1,000 ?m in diameter and constitute about 1-2 per cent of the fly ash obtained from the coal combustion processes. Because of their specific properties, namely their low density and high mechanical strength, cenospheres are an important subject of coal fired power plants. Research results indicate that cenospheres from coal combustion are constituted by aluminosilicate glasses with some crystalline phases like quartz, mullite and calcite. The high alumina content – roughly 25-27 wt per cent is responsible for the high mechanical strength, while density of most cenospheres is lower than 1 g/cm3. Regarding the formation process, there are correlations between the amount of cenospheres and the sodium and calcium content, in the different fly ash samples.
The economics of blended cements will largely depend on the landed cost of fly ash or slag. The common belief that it is a waste material and can be given away at throw away price has already vanished. Cement companies are prepared to pay better rates for consistent quality of fly ash.
Reference: Quality Trend In Indian Cements – A Decade Appraisal
AUTHORS: US Sinha, K Bhatnagar, R Gupta and MM Ali of National Council for Cement and Building Materials, India (NCCBM)
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SEEPEX introduces BN pumps with Smart Joint Access (SJA) to improve efficiency, reliability, and inspection speed in demanding rock blasting operations.
Designed for abrasive and chemical media, the solution supports precise dosing, reduced downtime, and enhanced operational safety.
SEEPEX has introduced BN pumps with Smart Joint Access (SJA), engineered for the reliable and precise transfer of abrasive, corrosive, and chemical media in mining and construction. Designed for rock blasting, the pump features a large inspection opening for quick joint checks, a compact footprint for mobile or skid-mounted installations, and flexible drive and material options for consistent performance and uptime.

“Operators can inspect joints quickly and rely on precise pumping of shear-sensitive and abrasive emulsions,” said Magalie Levray, Global Business Development Manager Mining at SEEPEX. “This is particularly critical in rock blasting, where every borehole counts for productivity.” Industry Context
Rock blasting is essential for extracting hard rock and shaping safe excavation profiles in mining and construction. Accurate and consistent loading of explosive emulsions ensures controlled fragmentation, protects personnel, and maximizes productivity. Even minor deviations in pumping can cause delays or reduce product quality. BN pumps with SJA support routine maintenance and pre-operation checks by allowing fast verification of joint integrity, enabling more efficient operations.
Always Inspection Ready
Smart Joint Access is designed for inspection-friendly operations. The large inspection opening in the suction housing provides direct access to both joints, enabling rapid pre-operation checks while maintaining high operational reliability. Technicians can assess joint condition quickly, supporting continuous, reliable operation.
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Applications – Optimized for Rock Blasting
BN pumps with SJA are designed for mining, tunneling, quarrying, civil works, dam construction, and other sectors requiring precise handling of abrasive or chemical media. They provide robust performance while enabling fast, reliable inspection and maintenance.With SJA, operators can quickly access both joints without disassembly, ensuring emulsions are transferred accurately and consistently. This reduces downtime, preserves product integrity, and supports uniform dosing across multiple bore holes.
With the Smart Joint Access inspection opening, operators can quickly access and assess the condition of both joints without disassembly, enabling immediate verification of pump readiness prior to blast hole loading. This allows operators to confirm that emulsions are transferred accurately and consistently, protecting personnel, minimizing product degradation, and maintaining uniform dosing across multiple bore holes.
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A leading explosives provider implemented BN pumps with SJA in open pit and underground operations. By replacing legacy pumps, inspection cycles were significantly shortened, allowing crews to complete pre-operation checks and return mobile units to productive work faster. Direct joint access through SJA enabled immediate verification, consistent emulsion dosing, and reduced downtime caused by joint-related deviations.
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Concrete
Digital process control is transforming grinding
Published
3 weeks agoon
February 20, 2026By
admin
Satish Maheshwari, Chief Manufacturing Officer, Shree Cement, delves into how digital intelligence is transforming cement grinding into a predictive, stable, and energy-efficient operation.
Grinding sits at the heart of cement manufacturing, accounting for the largest share of electrical energy consumption. In this interview, Satish Maheshwari, Chief Manufacturing Officer, Shree Cement, explains how advanced grinding technologies, data-driven optimisation and process intelligence are transforming mill performance, reducing power consumption and supporting the industry’s decarbonisation goals.
How has the grinding process evolved in Indian cement plants to meet rising efficiency and sustainability expectations?
Over the past decade, Indian cement plants have seen a clear evolution in grinding technology, moving from conventional open-circuit ball mills to high-efficiency closed-circuit systems, Roller Press–Ball Mill combinations and Vertical Roller Mills (VRMs). This shift has been supported by advances in separator design, improved wear-resistant materials, and the growing use of digital process automation. As a result, grinding units today operate as highly controlled manufacturing systems where real-time data, process intelligence and efficient separation work together to deliver stable and predictable performance.
From a sustainability perspective, these developments directly reduce specific power consumption, improve equipment reliability and lower the carbon footprint per tonne of cement produced.
How critical is grinding optimisation in reducing specific power consumption across ball mills and VRMs?
Grinding is the largest consumer of electrical energy in a cement plant, which makes optimisation one of the most effective levers for improving energy efficiency. In ball mill systems, optimisation through correct media selection, charge design, diaphragm configuration, ventilation management and separator tuning can typically deliver power savings of 5 per cent to 8 per cent. In VRMs, fine-tuning airflow balance, grinding pressure, nozzle ring settings, and circulating load can unlock energy reductions in the range of 8 per cent to 12 per cent. Across both systems, sustained operation under stable conditions is critical. Consistency in mill loading and operating parameters improves quality control, reduces wear, and enables long-term energy efficiency, making stability a key operational KPI.
What challenges arise in maintaining consistent cement quality when using alternative raw materials and blended compositions?
The increased use of alternative raw materials and supplementary cementitious materials (SCM) introduces variability in chemistry, moisture, hardness, and loss on ignition. This variability makes it more challenging to maintain consistent fineness, particle size distribution, throughput and downstream performance parameters such as setting time, strength development and workability.
As clinker substitution levels rise, grinding precision becomes increasingly important. Even small improvements in consistency enable higher SCM utilisation without compromising cement performance.
Addressing these challenges requires stronger feed homogenisation, real-time quality monitoring and dynamic adjustment of grinding parameters so that output quality remains stable despite changing input characteristics.
How is digital process control changing the way grinding performance is optimised?
Digital process control is transforming grinding from an operator-dependent activity into a predictive, model-driven operation. Technologies such as online particle size and residue analysers, AI-based optimisation platforms, digital twins for VRMs and Roller Press systems, and advanced process control solutions are redefining how performance is managed.
At the same time, workforce roles are evolving. Operators are increasingly focused on interpreting data trends through digital dashboards and responding proactively rather than relying on manual interventions. Together, these tools improve mill stability, enable faster response to disturbances, maintain consistent fineness, and reduce specific energy consumption while minimising manual effort.
How do you see grinding technologies supporting the industry’s low-clinker and decarbonisation goals?
Modern grinding technologies are central to the industry’s decarbonisation efforts. They enable higher incorporation of SCMs such as fly ash, slag, and limestone, improve particle fineness and reactivity, and reduce overall power consumption. Efficient grinding makes it possible to maintain consistent cement quality at lower clinker factors. Every improvement in energy intensity and particle engineering directly contributes to lower CO2 emissions.
As India moves toward low-carbon construction, precision grinding will remain a foundational capability for delivering sustainable, high-performance cement aligned with national and global climate objectives.
How much potential does grinding optimisation hold for immediate energy
and cost savings?
The potential for near-term savings is substantial. Without major capital investment, most plants can achieve 5 per cent to 15 per cent power reduction through measures such as improving separator efficiency, optimising ventilation, refining media grading, and fine-tuning operating parameters.
With continued capacity expansion across India, advanced optimisation tools will help ensure that productivity gains are not matched by proportional increases in energy demand. Given current power costs, this translates into direct and measurable financial benefits, making grinding optimisation one of the fastest-payback operational initiatives available to cement manufacturers today.
Concrete
Refractory demands in our kiln have changed
Published
3 weeks agoon
February 20, 2026By
admin
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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