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Gunning for lower downtime

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For minimising downtime, techniques like gunning and shotcreting are being adopted, instead of using pre-fired bricks in refractories.

Portland cement manufacturing is an energy intensive operation, and a refractory lining that can withstand high temperatures, alkalinity and corrosive conditions is absolutely essential.

Refractories play a critical role in both the rotary kiln lining, and the lining of the high volume static equipment areas that comprise a modern pre-calciner kiln system. The refractory kiln process involves pyro-processing of raw material, and extremely high temperature in rotary kilns. Often the kiln feeds are alkaline in nature, generate corrosive reactants. Hence the importance of refractories with strong resistance to such characteristics and having robust thermal efficiencies in cement manufacturing. ‘After two years of depressed market, currently refractory market has stabilised a bit and it seems that recovery is underway in 2018,’ says Ish Mohan Garg, Managing Director, Calderys.

While iron and steel industry is the major consumer of refractories with 65-75 per cent share, cement is the second major consumer of the equipment with 10-15 per cent share of total refractory consumed, followed by glass, non-ferrous metals, petrochemicals and hydrocarbons, which also involve high temperature processes.

Imports
About 30 per cent of refractories consumed in India is imported, mostly from China. ‘The primary driver for these imports is the abundant availability of raw material there, especially magnesite. To that extent, we cannot wish away the role of China and this is also the reason why refractory companies have set up plants in China,’ says Sameer Nagpal, CEO, Dalmia-OCL. However, the recent raw material crisis in China provides immense opportunity for India to bolster its domestic refractory industry by allowing it to source and secure raw materials from other countries with zero import duty.

But, certain policy anomalies have to be corrected to achieve this, says Garg. ‘Refractory is essentially a "Make in India" business model where we import raw materials and create value-added products in India. But while import duty on raw material is 5 per cent, that on finished product is 2.5 per cent. This import duty has to be increased to encourage domestic manufacturing activity.’

With India becoming the world’s second largest steel and cement producer, it should also be a leading refractory producer to support these industries. ‘Indian companies have the wherewithal to emerge as a globally competitive player and we are actively pursuing this direction. We are looking at acquisitions in Europe that can help us build scale and access latest technologies,’ says Nagpal.

‘Due to its low-cost and highly skilled workforce, India is a competitive market for refractory manufacturing and is also a sourcing base for Americas and Europe,’ Nagpal adds. Dalmia-OCL has a network spread across different countries and exports constitute 15 per cent of its revenue.

However, Garg differs on competitiveness of the Indian refractory industry. ‘Raw materials being 60-70 per cent of the total cost of refractory makes it difficult for Indian refractory industry to become globally competitive, due to sheer dependence of Indian manufacturers on imported raw materials. As a country, our ability to tap into global/ regional market is very much restricted,’ he points out.

Technology
As cement demand picks up and capacity utilisation goes up, cement manufacturers may want to minimise the downtime for replacing refractory lining. ‘This is giving rise to demand for higher performing bricks with higher life and shorter application time. Techniques like gunning and shotcreting using monolithic refractory, which is in powder form and takes shape after being applied, instead of using pre-fired bricks, is also gaining currency,’ says Nagpal.

Dalmia-OCL has formed a joint venture with a leading European refractory company for bringing to India the latest in gunning and shotcreting products, and is setting up the most modern monolithic plant in Katni, Madhya Pradesh.

Also, Indian cement makers use a lot of alternative fuels, which puts tremendous thermochemical pressure on refractory. Hence second or third generation spinels, hybrid refractories are coming up to take care of the increased thermochemical loads. Another trend is the effort towards reduction of thermal losses by introducing energy-saving refractories. New concepts are also coming up on thermal insulation of pyro system.

In the past, the major focus had been on the kiln performance, primarily productivity but with stricter environmental norm there has been major shift on the cement kiln system refractories too. ‘Well known hexavalent chrome problem associated with Mag Chrome refractories has made them unusable in cement kiln. In the kiln burning zone, Mag Chrome bricks have been substituted by wide range of alternate spinel products, e.g. MagAl, Hercenyte and others like zirconia containing magnesia, etc.,’ says Garg of Calderys.

Ammonia injection, once stricter NOx and SOx norms is implemented, would put significantly more stress on the refractory in the cement kiln system. Refractory manufacturers need to gear up for these upcoming regulatory norms.

Cement kilns in India are virtually being used as incinerator, where pharma and municipal wastes are common feed as fuel. This obviously has changed the kiln operating environment. This has resulted in increased coating build in kiln inlet as well as Spurrite ring formation within the kiln. On many occasions, the clinker is dustier compared to the past. ‘These changes obviously have called for refractories with different features. Incorporation of the requisite features has turned out to be much easier in monolithic, primarily castables, compared to bricks. Against this backdrop, castable in kiln inlet, tip casting, bull nose and cooler bench has become a standard practice. With the advent of shotcrete installation process, for identical castable formulations, faster installation extension of refractory life, by repair, has been possible,’ says Garg.

Boost domestic manufacturing
While emphasising the need to boost local refractory manufacturing, Nagpal of Dalmia-OCL suggested reduction of duties on raw material import; enabling mining policies for minor minerals like bauxite, quartzite, magnesite, etc., which are critical refractory raw materials, to reduce dependence on external sources; and support to refractory and ceramics R&D to boost local innovation, for this purpose.

The primary support from government should be on the following three fronts – ‘technology development, developing young talent and sustainability,’ says Garg of Calderys.

On behalf of IRMA, Calderys has set up Centre of Excellence at IIT BHU aimed at technological advances for making industry globally competitive. ‘We need to accelerate such advances in multiple Institute of repute,’ Garg adds.

For decades, the industry has been dumping used refractory in landfills, however, more sustainable way is to extract key raw materials from the same, use it again for refractory. ‘We trust Government should work with user industry to enable reverse supply chain of used refractory,’ says Garg.

-BS SRINIVASALU REDDY

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Economy & Market

Smart Pumping for Rock Blasting

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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.

Key Features

  • Compact Footprint: Fits truck-mounted mobile units, skid-mounted systems, and factory installations.
  • Flexible Drive Options: Compact hydraulic drive or electric drive configurations.
  • Hydraulic Efficiency: Low-displacement design reduces oil requirements and supports low total cost of ownership.
  • Equal Wall Stator Design: Ensures high-pressure performance in a compact footprint.
  • Material Flexibility: Stainless steel or steel housings, chrome-plated rotors, and stators in NBR, EPDM, or FKM.

Operators benefit from shorter inspection cycles, reliable dosing, seamless integration, and fast delivery through framework agreements, helping to maintain uptime in critical rock blasting processes.

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.

The combination of equal wall stator design, compact integration, flexible drives, and progressive cavity pump technology ensures continuous, reliable operation even in space-limited, high-pressure environments.

From Inspection to Operation

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.

“The inspection opening gives immediate confidence that each joint is secure before proceeding to bore holes,” said a site technician. “It allows us to act quickly, keeping blasting schedules on track.”

Framework agreements ensured rapid pump supply and minimal downtime, supporting multi-site operations across continents

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Concrete

Digital process control is transforming grinding

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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.

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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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