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The future shall demand less energy intensive greener cements

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Dr Sujit Ghosh, Executive Director – New Product and R&D, Dalmia Cement (Bharat), discusses the alternative raw materials that can be used in the production of cement and its impact on carbon emissions while underscoring the major challenges faced in using other cementitious materials.

What are the core raw materials used in the production of cement?

The core raw materials used in the production of cement are limestone (calcium carbonate) and clay (a source of silica). First, the limestone is roasted/calcined to create activated lime (CaO) in a calciner and then the activated lime along with siliceous clay is proportioned along with some other minor ingredients into a raw mix design and charged inside a kiln to form cement clinker; which is basically made of complex compounds of calcium-silica-oxides primarily, which when mixed with water, reacts, to form a cementitious gel paste that binds all aggregates together and when dried up provides strength to the concrete/plaster, made with cement and the aggregates.

Limestone (calcium carbonate) and clay (silica), which are both available in nature, are inert materials. Only when they are heat-treated at temperatures above 900oC, they become activated lime (CaO) and activated/amorphous silica (SiO2), and fuse inside the cement kiln in liquid form to form complex calcium-silica-oxides, that is cement or cement clinker.

What are the alternative raw materials that can be used in the production of cement? How does that impact the process of production? 

As explained in the previous paragraph, any activated lime (CaO) and/or activated/amorphous silica (SiO2), could be potential sources of cementitious material.  These could be alternative raw materials for cement production. Thus far, the most widely found and used sources of alternative materials are primarily ‘fly ash’ and ‘blast furnace slag’. Fly ash is a waste product from the burning of coal (as in a thermal power plant etc). It primarily contains amorphous/activated silica (SiO2), but very little active lime (CaO) in the Indian context. So, it is not reactive on its own, it needs activated lime (CaO) to become cementitious – which is available from cement clinker, when the two are co-processed in a cement manufacturing plant. Blast furnace slag likewise is a waste product from the steel manufacturing process and does contain some activated silica and activated lime, but again, not in the proportion/concentration to itself become cementitious. It also has to be co-processed with a cement clinker in a cement manufacturing plant. Overall, these alternative or supplementary cementitious materials, which are other industry wastes, due to the need for co-processing with cement clinker, may add some costs to the production process, but since the use of such alternative raw materials, reduces the dependence on highly energy-intensive clinker, they are welcome by the cement manufacturing fraternity, that helps lower the carbon footprint of production. These cements are called ‘blended cements’ – either fly ash blended (popularly known as PPC) or slag blended (popularly known as PSC) or fly ash + slag blended (popularly known as PCC).

How can the cost of production be reduced by using alternative or supplementary raw materials in cement production?

Since the use of alternative / supplementary cementitious materials has been prevalent in the world and in India, for blended cement production, for the last couple of decades, the demand for such other industry wastes (primarily from thermal power plant or steel plant) has been increasing steadily. This has led to a steep increase in prices for these industry wastes (mainly slags from steel plants) which otherwise were previously dumped in landfills, by opportunistic players and profiteering groups. Also, since steel plants and thermal power plants are not co-located with cement plants geographically, transportation costs of such bulky waste materials have also been increasing. Cost of blended cement production has to reduce or at least maintain at par, as well as, at the same time assist the nation in beneficially getting rid of other-industry-wastes. Cement players can do justice to climate-change by producing less energy intensive blended cements that are in no way inferior in quality to pure-clinker cements. Transport subsidies should also be provided to cement manufacturers by the government as well as at the same time try and administer some polluter-to-pay mechanism (so that these wastes are not conveniently dumped away in nearby landfills by the relevant industries).

Kanika Mathur

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Concrete

Cement industry sees record growth amid booming construction demand

Glimpses from the 13th Cement Expo in Hyderabad.

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“There’s no waste in India; everything is wealth,” was the thought-provoking idea that came from Dr Mohapatra, DG, NCCBM, as he shared his views on ‘Circular Economy and Sustainability’ at the recently concluded 8th Indian Cement Review Conference. The questions he raised and the ideas he presented were enriched with his decades of experience of working on research, development and analysis of alternative raw materials and renewable fuel for the cement industry. He highlighted the struggles in manufacturing blended cement and the opportunities that are available for its use. Finally, he suggested ways to ensure that each manufacturing plant falls within the gamut of a circular economy.

On his part Dr Sriharsha Reddy, Director, IMT Hyderabad, elaborating on ‘ESG – Green Financing: A new opportunity for the cement industry’, brought to light a number of important issues pertaining to fund procurement through traditional methods and the challenges therein.

Highlighting his views on carbon capture and its benefits for the cement manufacturers, Saurabh Palsania, Executive Director and Group Commercial Head, Dalmia Cement (Bharat), underscored the need to implement innovative technology and most importantly a proper strategy, in order to revolutionise the efforts towards net zero emissions. “Carbon capture, utilisation and storage (CCUS) is an investment-intensive process that also requires a commitment of time and labour. Keeping all these factors in mind, cement companies need to chart out an effective strategy to incorporate CCUS into their eco systems, ensure purity of the captured carbon and channel it towards predetermined activities for its optimum utility,” he said.


Pratap Padode, Founder & President, FIRST Construction Council,
summarised the challenges faced by the Indian cement industry as well as the growth opportunities it presented for manufacturers in terms of technological innovation and capacity building. He supported his opinions with statistical findings and his in-depth knowledge about the Indian cement and construction industries.

Several discussions from the event highlighted several critical aspects of the cement industry.

ESG – Green Financing: A new opportunity for the cement industry

The cement industry has made progress in reducing energy consumption and power usage, but the challenge now lies in reducing carbon emissions. With breakthrough carbon capture technologies and solar calcination of limestone, the industry can work towards achieving zero CO2 emissions. However, the economic value of carbon capture needs to be explored, with government support through carbon labelling, trading, and green funds. Other solutions such as non-contact grinding and heat recovery from kilns can also be explored to bring emissions to zero. The industry can achieve sustainability and low carbon footprint with digital transformation and well-planned processes. To finance green initiatives, traditional lending institutions such as banks are now considering the economic value of eco-friendly practices. However, long-term loans remain a challenge, and other lending institutions such as venture capitalists and government grants need to be explored.

Demystifying digitalisation and maximising the value chain impact

Digitalisation is crucial in optimising all stages of cement production. Industry 4.0 has provided tools that help determine the desired product quality, which is vital in meeting customer demands. As the importance of ESG continues to grow, digitalisation can help improve processes and reduce environmental impact. Transparency is also key, and a cloud-based platform can facilitate this. Automation at the plant level is vital for both efficiency and safety. However, it is important to remember that profitability is also essential for sustainability. Therefore, implementing digital tools and automation must be done with a focus on achieving profitability without compromising on sustainability.

Innovative supply chain strategies in the cement industry

Innovative supply chain strategies are crucial for the cement industry to remain competitive, with logistics and transportation being at the forefront. Industry experts discussed that the key to cost efficiency lies in innovation in first and last mile connectivity. However, logistics should not be viewed as merely a commercial function, but rather as a technology function. By investing in technology, cement manufacturers can drive the supply chain in a much better way, enabling them to evaluate processes from a revenue angle rather than just cost.

Industry experts also agreed that logistics is the only differentiator a cement company can have today, rather than cost or quality. As such, it is essential for cement manufacturers to explore non-renewable sources of energy to address the energy demand for distribution. Automation is also considered a key element for future logistics solutions. With these innovative strategies in place, the cement industry can increase efficiency and sustainability, which in turn can positively impact the bottom line.
On his part, Gaurav Gautam, Head of Sales, Beumer Group, highlighted the innovations in material handling systems that the is undertaking in order to make the movement of finished products smoother along the supply chain. The company specialises in tailor-made intralogistics solutions that help maximise productivity of cement companies.

Truly, the 8th Indian Cement Review Conference brought the industry together in a informative discussion on thought-provoking ideas and suggestions. The presentation weremade by Jayesh Patil, Assistant Manager, Flow Aids, Martin Engineering; Nischal Basavaraj, Regional Head – South, Liugong India; Sasi M Kumar, Business Development Manager – Cement, ExxonMobil; and S Chakravarti, Managing Director, Ecodea Projects and Control.

The conference was held alongside the 13th Cement Expo and Indian Cement Review Awards 2023. Partners supporting the event included: Presenting Partner: ExxonMobil Lubricants; Gold Sponsor: JK Cement and PhillipCapital India; Silver Sponsor: LiuGong India; Associate Sponsor: Humboldt Wedag India; Presentation Partners: Martin Engineering Company India, Beumer India, and Ecodea Projects & Control; Logo Sponsor: Stotz Gears; and Exhibiting Partners: Toshniwal Industries; TIDC (Murugappa Group), and Ringfeder Power Transmission India.

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Concrete

Solutions to protect concrete against monsoon

Concrete patching compounds for repairing concrete window ledges.

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As the monsoon season rapidly approaches in India, the urgency to address potential damage to the commonly used building material – concrete –intensifies. Weathering and loading can cause cracks and deterioration, impacting both the structure’s integrity and aesthetics and leading to water penetration and reinforcement corrosion. To ensure durability and prevent further damage, it is essential to promptly repair any concrete cracks.

Several structures face a common problem during monsoon season – holes created by water penetration or impact in concrete window sills. These not only affect the window’s appearance and functionality but also pose a safety hazard. Fortunately, various concrete repair compounds are available in India to fill such holes and restore the window sill. Don’t wait until it’s too late –CW researches some of the concrete repair compounds that could help protect concrete structures from monsoon damage:

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Concrete

Heidelberg Materials secures SBTi validation

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The Science-Based Targets Initiative (SBTi) has validated Heidelberg Materials’ new 2030 CO2 reduction targets. The targets have a base year of 2020 and conform to a 1.5°C climate change framework. Per tonne of cementitious material, the producer is now committed to reducing its Scope 1 CO2 emissions by 24 per cent, its Scope 2 CO2 emissions by 65 per cent and its Scope 3 emissions by 25 per cent.

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