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Gypsum is used in cement to avoid flash-set

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Pradeep Kumar Chouhan – General Manager (QC and Environment), Udaipur Cement Works, sheds light on the role of gypsum and its manufacturing process.

Explain the role of gypsum in the cement manufacturing process.
Gypsum plays an important role in controlling the rate of hardening of the cement. Since it delays the settling of cement, it allows a longer working time, transporting, and placing. If gypsum is not added with a clinker during the cement manufacturing process, then the cement produced will immediately be set in addition to water and masons will not find time to work with it.
Gypsum is colourless, transparent, and naturally occurring in crystalline form as a mineral. It is widely used in our day-to-day life. It is a primary ingredient of toothpaste, used as a colour additive for drugs and cosmetics, as a food additive, plaster for orthopaedic use etc.
Generally, gypsum occurs in nature called mineral gypsum. Another variety of gypsum produced during production of common salt in coastal regions, particularly in Gujarat and Tamil Nadu, is called marine gypsum. Phosphoric Acid plants are important sources of by-product Phosphogypsum. Nowadays, chemical gypsum or synthetic gypsum (SynGyp) are also widely utilised as an alternative source of mineral gypsum for manufacturing of cement. The chemical gypsum or synthetic gypsum are produced from dyes and chemical industries and during flue gas desulphurisation (FGD) for abatement of SO2 pollution from sources like power plant for sulphur dioxide controlling system as an additional pollution control device.
Gypsum (CaSO4.2H2O) added with clinker while grinding in the cement mill to produce finished product i.e., cement.

C3A is the phase with the highest hydration speed
3CaO.Al2 O3 + n H2O fast reactions CAH + profuse exothermic heat
C3A + 6H2O▼ C3AH6
This is controlled by gypsum,
C3A + H2O + CaSO4- C4AS3H12 – C4AS3H32
Chemical reaction in the presence of gypsum is given below
3CaO. Al2O3 + 3CaSO4 . 2H2O + nH2O → 3CaO. Al2 O3 . 3CaSO4 . 32H2O
(Ettringite: calcium tri sulpho aluminate hydrate) + moderate exothermic heat
What proportions of gypsums are added in various types of cements produced? Tell us in detail about the composition and percentage.
Gypsum is normally used in various types of cement to maintain the SO3 in cement as per specification of BIS, based on Purity of Gypsum as CaSO4.2H2O its proportion in cement varies in the tune of 4 to 10 per cent. Limit for SO3 per cent in cement is 3.5 per cent, accordingly based on purity of gypsum as CaSO4.2H2O, proportion of gypsum is as follows:

Tell us about the process of obtaining gypsum by your organisation. What are the key resources utilised?
Udaipur Cement Works Limited (UCWL) is uses two types of gypsum i.e., Mineral and Chemical Gypsum for its cement products (i.e. OPC and PPC).
UCWL procures mineral gypsum from Rajasthan State Mines and Minerals Ltd. (RSMML) through road transportation.
Chemical gypsum generated primarily by dyes manufacturing industries using sulphuric acid in the manufacture of dye intermediates. The waste/effluent containing sulphuric acid is neutralised with limestone to produce large quantities of chemical gypsum in these industries. At present, UCWL procures chemical gypsum from Chemical Industries of Gujarat through road transportation.

Tell us about the key technical feasibility factors that make gypsum viable for mixing with cement?
As I mentioned earlier, gypsum is used in cement to avoid flash-set. In other words, gypsum delays the setting of cement. The main purpose of adding gypsum in the cement is to slow down the hydration process of cement once it is mixed with water. The hydration process starts when water is added into cement. Water reacts with C3A and hardens. This happens in a very short time, which doesn’t allow cement for transporting, mixing, and placing with construction building material and other useful materials. In presence of gypsum in the cement and water is added to it, reaction with C3A particles takes place to form ettringite (calcium tri sulpho aluminate hydrate). This ettringite is initially formed as very fine-grained crystals, which form a coating on the surface of the C3A particles. These crystals are too small to bridge the gaps between the particles of cement. Therefore, the cement mix remains plastic and workable. This is an important role of gypsum for strength, composition and workability of concrete. The gypsum retards the process of hydration, so it is termed as retarding agent of cement.
Clinker, which has all cementitious properties, after mixing of water it gets set quickly without gypsum. To avoid the quick set and give a workability time gypsum is mixed with clinker in the tune of 4 to 9 per cent (based on the purity of gypsum as CaSO4.2H2O). Limit of BIS for initial setting time is above 30 minutes and final setting is less than 600 minutes. Normally, cement is produced having a setting time between 60 to 150 minutes. We can say gypsum is not only a retarding agent of cement but also provides strength and hardness to cement.

What is the preparation or processing required to make gypsum ready to mix with the clinker?
Gypsum is added to the clinker just before the final grinding to make it into the finished product i.e., cement. Gypsum is a hygroscopic material and is sticky in nature. Its composition and physical characteristics vary from region to region in case of mineral gypsum and purity or quality matters for chemical or synthetic gypsum.
Since, gypsum is used as one of the prime materials in cement and due to its hygroscopic nature, it requires proper cover shed to avoid direct sunlight and moisture. Moisture control is one of the complex handling issues for storage of gypsum and to retain its quality. Therefore, gypsum stockpiles should be stored in a building or a storage in a cover shed which is preferably dry, rain proof and moisture proof.
Due to sticky nature, further procedures of handling, loading, conveying and feeding into cement mills require precautions and robust systems to ease this material flow and feed into cement mills for mixing with clinker. There are, however, alternative sources of gypsum available which may be able to partly substitute natural gypsum. Synthetic gypsum can be produced by using limestone powder with sulphuric acid. For making gypsum limestone to be ground at the fineness of 100 – 200 mm.
Dilute sulphuric acid to be added to the limestone powder as per molar ratio of calcium and sulphate to produce CaSO4.2HO. Gases generated during treatment to be handled by suitable pollution control equipment. Produced gypsum is required to be sun dried till moisture is reduced to the level of 10 to 15 per cent. Solar drying method for removal of moisture is one of the best available, less complex, and economical technologies for drying gypsum where solar radiation is high.

How does automation help in obtaining this mineral and increasing productivity
of the unit?
Any kind of possible automation in the manufacturing process will help increase productivity and sustain business. Right now, UCWL does not have any processing unit for manufacturing gypsum.
To bring down moisture in mineral/chemical/synthetic gypsum at desired level, solar drying method can be adopted. If the solar drying system is controlled with a Programmable Logic Controller (PLC) to check and control the indoor temperature and humidity, lower energy cost and higher material drying performance can be obtained through automation.
However, automation of gypsum manufacturing processes helps to increase productivity and availability. During the synthetic gypsum manufacturing, dosing of sulphuric acid with automation will help to maintain the pH of the mix. Mixing and treatment time regulation is required and can be controlled through automation. Fineness of limestone powder can also be controlled for treatment with sulphuric acid.

What are the sustainability measures taken by your organisation in obtaining and processing the desired quality of gypsum?
UCWL started trials of various industrial waste to use as a set retarder for replacement of gypsum. Our organisation is a pioneer in the utilisation of Jarosite in its cement manufacturing process as a partial substitute of gypsum. JK Lakshmi Cement (JKLC) Group’s research and development department is also working on making gypsum from Limestone rejected through screen during the crushing
of limestone.

Does your organisation recycle gypsum? Tell us more about the process.
Since, once gypsum is added to cement it cannot be recycled, however at UCWL, we are using various materials as a set retarder to replace mineral gypsum.
Other industrial wastes like chemical gypsum are used to the tune of 40 to 60 per cent of the total gypsum in place of mineral or marine gypsum. As I said, for the first time in India, UCWL started use of Jarosite (an industrial waste from the zinc industry’s smelting process) as a part replacement of mineral gypsum. Presently 10 per cent of mineral gypsum is replaced by use of Jarosite.

What are the major challenges faced in handling and obtaining gypsum for the manufacturing process?
The cement industry is a major user of gypsum. India’s domestic resources of gypsum are large enough to meet increased demand. Rajasthan has one of the richest sources of mineral gypsum however, it is a limited natural resource in view of increasing demand of the cement industry as a whole. It is also used for the manufacturing of value-added products like POP. Cement industry is also looking for other alternatives i.e., chemical gypsum, POP waste and industrial waste. Consumption and demand of gypsum will also increase by rapid growth of the cement industry, which leads to increased dependence upon alternatives of mineral gypsum viz. synthetic and chemical gypsum to meet cement demand.
There are two ways to obtain gypsum either from natural resources i.e., mineral gypsum and to some extent marine gypsum or chemical or synthetic gypsum generated from dyes and chemical industries and through flue gas desulphurisation (FGD) process.
To obtain mineral gypsum state-of-the-art technology needs to be adopted for the exploitation of deep-seated gypsum. Synthetic gypsum can be manufactured as per specific requirement and quality depends upon purity of lime.
Major challenges during the manufacturing process of Synthetic Gypsum (SynGyp) are as follows.
a) Availability of sulphuric acid, price variation of sulphuric acid as its availability depends on other industries production and consumption. Sulphuric acid is majorly used by fertiliser manufacturing units, hence, during crop seasons availability of sulfuric acid affects badly.
b) Quality of lime w.r.t. purity
c) Maintenance of Process is comparatively higher.
d) Drying of produced gypsum to get desired level of moisture.
e) Safety measures are required due to the use of sulphuric acid.
Nowadays, FGD generated gypsum is getting more attention among industries. High market demand for FGD gypsum is expected to encourage companies to install FGD systems in their power plants. Research shows that more than 85 per cent of FGD systems installed across the globe are wet systems. Rise of the construction industry and agricultural sector is expected to create opportunities for FGD manufacturers over the coming years, which will aid the expansion of synthetic gypsum market size as well.
Through manufacturing of synthetic gypsum, industry can reduce overall environmental impacts and their carbon footprint. This is a win-win situation for both generators as well as users of the synthetic gypsum (SynGyp). SynGyp is the best sustainable alternative for the environment through conservation of mineral gypsum natural deposits.

-Kanika Mathur

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Adani’s Strategic Emergence in India’s Cement Landscape

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4 days ago

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September 16, 2025

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Milind Khangan, Marketing Head, Vertex Market Research, sheds light on Adani’s rapid cement consolidation under its ‘One Business, One Company’ strategy while positioning it to rival UltraTech, and thus, shaping a potential duopoly in India’s booming cement market.

India is the second-largest cement-producing country in the world, following China. This expansion is being driven by tremendous public investment in the housing and infrastructure sectors. The industry is accelerating, with a boost from schemes such as PM Gati Shakti, Bharatmala, and the Vande Bharat corridors. An upsurge in affordable housing under the Pradhan Mantri Awas Yojana (PMAY) further supports this expansion. In May 2025, local cement production increased about 9 per cent from last year to about 40 million metric tonnes for the month. The combined cement capacity in India was recorded at 670 million metric tonnes in the 2025 fiscal year, according to the Cement Manufacturers’ Association (CMA). For the financial year 2026, this is set to grow by another 9 per cent.
In spite of the growing demand, the Indian cement industry is highly competitive. UltraTech Cement (Aditya Birla Group) is still the market leader with domestic installed capacity of more than 186 MTPA as on 2025. It is targeted to achieve 200 MTPA. Adani Cement recently became a major player and is now India’s second-largest cement company. It did this through aggressive consolidation, operational synergies, and scale efficiencies. Indian players in the cement industry are increasingly valuing operational efficiency and sustainability. Some of the strategies with high impact are alternative fuels and materials (AFR) adoption, green cement expansion, and digital technology investments to offset changing regulatory pressure and increasing energy prices.

Building Adani Cement brand
Vertex Market Research explains that the Adani Group is executing a comprehensive reorganisation and consolidation of its cement business under the ‘One Business, One Company’ strategy. The plan is to integrate its diversified holdings into one consolidated corporate entity named Adani Cement. The focus is on operating integration, governance streamlining, and cost reduction in its expanding cement business.
Integration roadmap and key milestones:

  • September 2022: The consolidation process started with the $6.4 billion buyout of Holcim’s majority stakes in Ambuja Cements and ACC, with Ambuja becoming the focal point of the consolidation.
  • December 2023: Bought Sanghi Industries to strengthen the firm’s presence in western India.
  • August 2024: Added Penna Cement to the portfolio, improving penetration of the southern market of India.
  • April 2025: Further holding addition in Orient Cement to 46.66 per cent by purchasing the same from CK Birla Group, becoming the promoter with control.
  • Ambuja Cements amalgamated with Adani Cement: This was sanctioned by the NCLT on 18th July 2025 with effect from April 1, 2024. This amalgamation brings in limestone reserves and fresh assets into Ambuja.
  • Subject to Sanghi and Penna merger with Ambuja: Board approvals in December 2024 with the aim to finish between September to December 2025.
  • Ambuja-ACC future integration: The latter is being contemplated as the final step towards consolidation.
  • Orient Cement: It would serve as a principal manufacturing facility following the merger.

Scale, capacity expansion and market position
In financial year-2025, Adani Cement, including Ambuja, surpassed 100 MTPA. This makes it one of the world’s top ten cement companies. Along with ACC’s operations, it is now firmly placed as India’s second-largest cement company. In FY25, the Adani group’s sales volume per annum clocked 65 million metric tonnes. Adani Group claims that it now supplies close to 30 per cent of the cement consumed in India’s homes and infrastructure as of June 2025.
The organisation is pursuing aggressive brownfield expansion:

  • By FY 2026: Reach 118 MTPA
  • By FY 2028: Target 140 MTPA

These goals will be driven by commissioning new clinker and grinding units at key sites, with civil and mechanical works underway.
As of 2024, Adani Cement had its market share pegged at around 14 to 15 per cent, with an ambition to scale this up to 20 per cent by FY?2028, emerging as a potent competitor to UltraTech’s 192?MTPA capacity (186 domestic and overseas).

Strategic advantages and competitive benefits
The consolidation simplifies decision-making by reducing legal entities, centralising oversight, and removing redundant functions. This drives compliance efficiency and transparent reporting. Using procurement power for raw materials and energy lowers costs per ton. Integrated logistics with Adani Ports and freight infrastructure has resulted in an estimated 6 per cent savings in logistics. The group aims for additional savings of INR 500 to 550 per tonne by FY 2028 by integrating green energy, using alternative fuel resources, and improving sourcing methods.

Market coverage and brand consistency
Brand integration under one strategy will provide uniform product quality and easier distribution networks. Integration with Orient Cement’s dealer base, 60 per cent of which already distributes Ambuja/ACC products, enhances outreach and responsiveness.
By having captive limestone reserves at Lakhpat (approximately 275 million tonnes) and proposed new manufacturing facilities in Raigad, Maharashtra, Adani Cement derives cost advantage, raw material security, and long-term operational robustness.

Strategic implications and risks
Consolidation at Adani Cement makes it not just a capacity leader but also an operationally agile competitor with the ability to reap digital and sustainability benefits. Its vertically integrated platform enables cost leadership, market responsiveness, and scalability.

Challenges potentially include:

  • Integration challenges across systems, corporate cultures, and plant operations
  • Regulatory sanctions for pending mergers and new capacity additions
  • Environmental clearances in environmentally sensitive areas and debt management with input price volatility

When materialised, this revolution would create a formidable Adani–UltraTech duopoly, redefining Indian cement on the basis of scale, innovation, and sustainability. India’s leading four cement players such as Adani (ACC and Ambuja), Dalmia Cement, Shree Cement, and UltraTech are expected to dominate the cement market.

Conclusion
Adani’s aggressive consolidation under the ‘One Business, One Company’ strategy signals a decisive shift in the Indian cement industry, positioning the group as a formidable challenger to UltraTech and setting the stage for a potential duopoly that could dominate the sector for years to come. By unifying operations, leveraging economies of scale, and securing vertical integration—from raw material reserves to distribution networks—Adani Cement is building both capacity and resilience, with clear advantages in cost efficiency, market reach, and sustainability. While integration complexities, regulatory hurdles, and environmental approvals remain key challenges, the scale and strategic alignment of this consolidation promise to redefine competition, pricing dynamics, and operational benchmarks in one of the world’s fastest-growing cement markets.

About the author:
Milind Khangan is the Marketing Head at Vertex Market Research and comes with over five years of experience in market research, lead generation and team management.

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Precision in Motion: A Deep Dive into PowerBuild’s Core Gear Series

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1 month ago

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August 16, 2025

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PowerBuild’s flagship Series M, C, F, and K geared motors deliver robust, efficient, and versatile power transmission solutions for industries worldwide.

Products – M, C, F, K: At the heart of every high-performance industrial system lies the need for robust, reliable, and efficient power transmission. PowerBuild answers this need with its flagship geared motor series: M, C, F, and K. Each series is meticulously engineered to serve specific operational demands while maintaining the universal promise of durability, efficiency, and performance.
Series M – Helical Inline Geared Motors: Compact and powerful, the Series M delivers exceptional drive solutions for a broad range of applications. With power handling up to 160kW and torque capacity reaching 20,000 Nm, it is the trusted solution for industries requiring quiet operation, high efficiency, and space-saving design. Series M is available with multiple mounting and motor options, making it a versatile choice for manufacturers and OEMs globally.
Series C – Right Angled Heli-Worm Geared Motors: Combining the benefits of helical and worm gearing, the Series C is designed for right-angled power transmission. With gear ratios of up to 16,000:1 and torque capacities of up to 10,000 Nm, this series is optimal for applications demanding precision in compact spaces. Industries looking for a smooth, low-noise operation with maximum torque efficiency rely on Series C for dependable performance.
Series F – Parallel Shaft Mounted Geared Motors: Built for endurance in the most demanding environments, Series F is widely adopted in steel plants, hoists, cranes, and heavy-duty conveyors. Offering torque up to 10,000 Nm and high gear ratios up to 20,000:1, this product features an integral torque arm and diverse output configurations to meet industry-specific challenges head-on.
Series K – Right Angle Helical Bevel Geared Motors: For industries seeking high efficiency and torque-heavy performance, Series K is the answer. This right-angled geared motor series delivers torque up to 50,000 Nm, making it a preferred choice in core infrastructure sectors such as cement, power, mining, and material handling. Its flexibility in mounting and broad motor options offer engineers’ freedom in design and reliability in execution.
Together, these four series reflect PowerBuild’s commitment to excellence in mechanical power transmission. From compact inline designs to robust right-angle drives, each geared motor is a result of decades of engineering innovation, customer-focused design, and field-tested reliability. Whether the requirement is speed control, torque multiplication, or space efficiency, Radicon’s Series M, C, F, and K stand as trusted powerhouses for global industries.

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Driving Measurable Gains

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1 month ago

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August 16, 2025

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Klüber Lubrication India’s Klübersynth GEM 4-320 N upgrades synthetic gear oil for energy efficiency.

Klüber Lubrication India has introduced a strategic upgrade for the tyre manufacturing industry by retrofitting its high-performance synthetic gear oil, Klübersynth GEM 4-320 N, into Barrel Cold Feed Extruder gearboxes. This smart substitution, requiring no hardware changes, delivered energy savings of 4-6 per cent, as validated by an internationally recognised energy audit firm under IPMVP – Option B protocols, aligned with
ISO 50015 standards.

Beyond energy efficiency, the retrofit significantly improved operational parameters:

  • Lower thermal stress on equipment
  • Extended lubricant drain intervals
  • Reduction in CO2 emissions and operational costs

These benefits position Klübersynth GEM 4-320 N as a powerful enabler of sustainability goals in line with India’s Business Responsibility and Sustainability Reporting (BRSR) guidelines and global Net Zero commitments.

Verified sustainability, zero compromise
This retrofit case illustrates that meaningful environmental impact doesn’t always require capital-intensive overhauls. Klübersynth GEM 4-320 N demonstrated high performance in demanding operating environments, offering:

  • Enhanced component protection
  • Extended oil life under high loads
  • Stable performance across fluctuating temperatures

By enabling quick wins in efficiency and sustainability without disrupting operations, Klüber reinforces its role as a trusted partner in India’s evolving industrial landscape.

Klüber wins EcoVadis Gold again
Further affirming its global leadership in responsible business practices, Klüber Lubrication has been awarded the EcoVadis Gold certification for the fourth consecutive year in 2025. This recognition places it in the top three per cent
of over 150,000 companies worldwide evaluated for environmental, ethical and sustainable procurement practices.
Klüber’s ongoing investments in R&D and product innovation reflect its commitment to providing data-backed, application-specific lubrication solutions that exceed industry expectations and support long-term sustainability goals.

A trusted industrial ally
Backed by 90+ years of tribology expertise and a global support network, Klüber Lubrication is helping customers transition toward a greener tomorrow. With Klübersynth GEM 4-320 N, tyre manufacturers can take measurable, low-risk steps to boost energy efficiency and regulatory alignment—proving that even the smallest change can spark a significant transformation.

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