Concrete

Clinker factor determines the CO2 footprint of cement

Published

4 years ago

June 13, 2022

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Manoj Kumar Rustagi, Chief Sustainability and Innovation Office (CSIO), JSW Cement, gives insights into the process of producing blended cement with supplementary cementitious materials for more strength and durability.

What are the core raw materials used in the production of cement?
Cement manufacturing is an energy and resource intensive process. Primary raw material is limestone which is mined, crushed, ground and mixed with bauxite, iron ore and other additives/correctives to make raw meal which is then heated to a temperature as high as ~1400°C in a horizontal kiln. Coal is the primary fuel which provides energy for the combustion process. The hot material is then cooled down to form clinker, an intermediate product for making cement. Clinker is further ground and blended with gypsum (mineral or chemical) to make the final product called ordinary Portland cement (OPC).
When clinker is blended with other supplementary cementitious materials like fly ash or slag or both, the product is known as blended cement.

What are the alternative raw materials that can be used in the production of cement? How does that impact the process of production?
Cement sector accounts for ~7 per cent of global CO2 emissions, and therefore it needs to be aggressive on its decarbonisation strategy wherein one of the primary lever is using alternative raw materials for the production of clinker and supplementary cementitious materials (SCMs) as cement/clinker replacements. Different fine-grained silica, silicate and alumina-silicate materials either natural or synthetic can be used in the final cement product to obtain a new eco-friendly cementitious binder with similar or better properties. The most commonly used SCMs are fly ash, granulated blast furnace slag, natural volcanic pozzolana etc.
When clinker is blended with other supplementary cementitious materials like fly ash, slag or both, products are called Portland Pozzolona Cement (PPC), Portland Slag Cement (PSC) and composite cement (CC) respectively. Blended cement products have a much lower carbon footprint than OPC. Since clinker manufacturing is the phase where most thermal energy is consumed and CO2 is emitted, reducing clinker factor in cement not only results in lowering the process CO2 but also the thermal energy and electrical energy requirements.
There are other alternative raw materials like Spent Pot Liner (SPL), red mud, lime sludge and steel slag, which are used in the clinker manufacturing to reduce consumption of limestone and consequently reducing the process CO2 that comes from limestone calcination.

Can cement maintain its quality standard with inclusion of supplementary raw materials as against limestone?
Yes, blended cement products not only maintain the most quality standards as OPC but also have superior properties in various parameters when compared to conventional OPC. Blended cements are preferred for its late strength, chemical resistance, alkali resistance and for coastal applications and dams and irrigation projects where they are technically most suitable.
The use of SCMs/mineral admixture/blended cements in concrete significantly helps in mitigating the expansion due to alkali silica reaction (ASR), due to the reduction in the availability of alkalis in the pore solution and the refinement of the pore structure. Not only does this reduce maintenance costs of infrastructure such as dams and bridges, but also allows the consumption of local aggregates that may contain deleterious materials. The reduced expansion in SCM-blended structures reduces the risk of expansion and cracking. This pozzolanic reaction also has a beneficial impact on resistance to sulphate attack.
Recently GCCA, India has published a detailed report on Benefits of Blended Cement Products, which has been prepared by NCCBM and reviewed by IIT, Madras, and that captures all the environment and technical benefits.

Explain the impact on carbon emission of the production unit when alternative raw materials are used in various proportions.
In cement manufacturing, CO2 is primarily emitted as a result of the chemical conversion process used in the production of clinker in which limestone (CaCO3) is first converted to lime (CaO) and then to hydraulic compounds. CO2 is also emitted during cement production by fossil fuel (primarily coal) combustion. Thus ~80-85 per cent of the CO2 emissions could be attributed to the production of clinker. This is partly reduced by using alternative raw materials and mineralisers in the raw mix design of clinker.
The amount of clinker in cement, known as clinker factor, determines the CO2 footprint of cement. In OPC, clinker factor is ~90 per cent thus, it has a carbon footprint of around 800 – 850 kg/MT of cement. When clinker is replaced with SCMs, the CO2 emissions are reduced as SCMs don’t have embodied carbon emissions. That is why blended cement have much lower carbon footprint than OPC. Currently in Portland Slag Cement (PSC) production almost 60 to 65 per cent of clinker is replaced with slag which results in ~60 per cent of CO2 footprint and the final carbon footprint is around 300 – 350 kg/MT. Similarly, in PPC where ~35 per cent of clinker is replaced, carbon footprint will be in the range of 500 – 550 kg/MT.

-Kanika Mathur

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Concrete

JK Lakshmi Cement Begins Rs 110 Billion Assam Plant Project

The 2.5 MTPA integrated cement plant is expected to be completed by FY2029.

Published

21 hours ago

October 31, 2026

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JK Lakshmi Cement has recently laid the foundation stone for Project Kamakshi, its first integrated cement manufacturing facility in Assam, marking its entry into Northeast India. The groundbreaking ceremony was held at Umrangso village in Dima Hasao district in the presence of Assam Chief Minister Himanta Biswa Sarma.

The project involves an investment of Rs 110 billion, including the mining lease, and will have an annual cement production capacity of 2.5 million tonnes, supported by a 1 million tonne clinkerisation unit. Scheduled for completion by FY2029, the facility is expected to generate employment for over 2,000 people while catering primarily to the growing Northeast market.

The integrated plant will feature dedicated railway sidings to facilitate efficient transportation of raw materials and finished cement, strengthening supply chain reliability and regional distribution.

Vinita Singhania, Chairperson and Managing Director, JK Lakshmi Cement, said, “”Project Kamakshi is the start of a long-term relationship with Assam and the wider North East. This is a region that is building fast, and it deserves quality cement made close to home. With this plant, we want to bring scale, jobs, and dependable supply to the region. At JK Lakshmi Cement, we believe that building a stronger India goes beyond infrastructure. It is also about growing together with the communities we serve.””

The investment aligns with the company’s strategy to expand into high-growth markets beyond its established presence in Northern, Western and Eastern India. The project is also expected to support regional economic development and infrastructure growth.

JK Lakshmi Cement aims to pursue its expansion plans while working towards its long-term target of achieving net-zero emissions by 2047.

Concrete

JK Lakshmi Cement to Expand EV Fleet to 120 Vehicles by March 2027

JK Lakshmi Cement has deployed more than 70 EVs across its logistics network.

Published

2 days ago

October 30, 2026

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JK Lakshmi Cement has deployed more than 70 electric vehicles (EVs) across its logistics network and plans to increase the fleet to 120 vehicles by March 2027. The expansion is part of its decarbonisation strategy, which aims to reduce transport-related emissions and improve operational efficiency.

The company has achieved nearly 100 per cent EV-based clinker dispatches from its Sirohi plant in Rajasthan to the Kalol Grinding Unit in Gujarat. The transition marks an increased use of electric mobility for long-haul cement transportation and is intended to lower the environmental impact of logistics operations.

The existing fleet operates on routes connecting the Sirohi plant with the Kalol Grinding Unit, Palanpur Unit and Surat Grinding Unit. JK Lakshmi Cement is working with electric vehicle logistics providers SwitchLabs and Billion E to support fleet deployment and manage transportation requirements across these routes.

The company expects the planned expansion to increase the use of electric mobility throughout its logistics network for moving cement and clinker. Chairperson and Managing Director Vinita Singhania said the programme reflected the integration of sustainable practices with the company’s focus on long-term business efficiency, while describing the Sirohi–Kalol transition as an important step in its wider decarbonisation strategy.

The EV programme forms part of JK Lakshmi Cement’s green logistics and sustainability roadmap, alongside initiatives to improve efficiency and reduce emissions across its value chain. The company has set a long-term target of achieving net-zero emissions by 2047. It is part of the JK Organisation and operates integrated cement plants in Rajasthan and Chhattisgarh, along with grinding units in Gujarat, Haryana and Odisha. The company has an annual turnover of more than Rs. 60 bn, combined cement capacity of approximately 18 mn t per annum and a target to raise capacity to 30 mn t by 2030. Its portfolio includes ready-mix concrete, gypsum plaster, wall putty, primer, adhesives and fly ash blocks.

Concrete

Martin Engineering Appoints Ashwini Khunte as India General Manager

Published

2 days ago

October 30, 2026

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Martin Engineering names Ashwini Khunte India General Manager to strengthen operations and drive growth across key bulk material handling sectors.

Pune

Martin Engineering, a global provider of bulk material handling solutions, has appointed Ashwini Khunte as General Manager of its India business, strengthening its leadership as the company expands its presence across the country’s cement, mining, steel, power and infrastructure sectors.

Khunte brings more than a decade of experience with Martin Engineering, having joined its Indian operations in 2013 as a Design Engineer, shortly after the company established its presence in the country in 2012.

A mechanical engineer by qualification, she spent her initial five years developing bulk material handling solutions in collaboration with the company’s operations team. During this period, she gained extensive experience addressing operational challenges in the steel, cement and coal industries. She subsequently moved into project engineering, managing major engineering, procurement and construction (EPC) and original equipment manufacturer (OEM) projects from initial enquiry to commissioning. Her responsibilities later expanded to overseeing Martin Engineering’s conveyor product portfolio in India, involving customer engagement, technical presentations and site visits across heavy industries.

In 2024, Khunte was promoted to Head of Sales & Marketing for the company’s Europe, Middle East, Africa and India (EMEAI) region. The position broadened her international market exposure and strengthened her strategic and commercial leadership capabilities.

Commenting on her appointment, Ashwini Khunte, General Manager, Martin Engineering India, said: “India represents a tremendous opportunity for Martin Engineering. The country’s continued investment in cement, mining, steel, power and infrastructure is creating increasing demand for safer, cleaner and more productive bulk material handling, and that’s exactly what we do. My priority will be to build on the strong foundations already established in India, while continuing to develop our people, strengthen customer relationships and bring practical solutions to the challenges faced by our industry.”

Robert Whetstone, Area Vice President – EMEAI, Martin Engineering, highlighted Khunte’s technical expertise, market understanding and leadership experience.

“Ashwini brings an exceptional combination of technical understanding, customer knowledge and commercial leadership. She has grown as Martin Engineering has grown, and has consistently demonstrated outstanding capability to transform her expertise into practical solutions. Her knowledge of the Indian market, together with her international experience, makes her ideally suited to lead our India business through its next stage of growth for years to come.”

Since establishing its Indian business in 2012, Martin Engineering has expanded its local workforce, manufacturing capabilities and dealership network. The company supplies conveyor products, transfer point solutions, material flow aids, training and technical support to bulk material handling industries. Khunte’s appointment positions the company to further strengthen customer relationships and expand its solutions portfolio in India’s growing industrial and infrastructure markets.