Connect with us

Economy & Market

Gypsum, the speed breaker

Published

on

Shares

Gypsum is the most essential ingredient of the finished cement. Though useful, handling of gypsum in a cement plant is not so easy since it is a hygroscopic material and very sticky in nature.

The terms cement and concrete are used interchangeably, although cement is actually an ingredient of concrete; gypsum is often added to cement to slow down the setting (hardens) time. Cement sets quickly and retarding that process allows workers to pour the mixture into the various forms or frames needed.

The majority of cement plants in Greece mainly use natural gypsum to prevent rapid cement setting. The partial or total replacement of gypsum by materials, which contain calcium sulphate, has been instigated by two facts. Firstly, the increasing availability of low-cost by-products containing calcium sulphate and secondly, the prospect of the gypsum quarries to mine, in the near future, a rock that is a mixture of gypsum and anhydrite.

FGD gypsum, a waste material of the desulphurisation process in coal burning power plants, to convert SO3 content of flue gases into gypsum, is an important alternative source of chemical gypsum. The experiments done with only FGD gypsum shows that the setting time was influenced by the percentages of FGD gypsum addition in the mortars tested. The initial and final setting time increased with increasing FGD gypsum ratio. The compressive strength also was affected by increase of FGD gypsum in the mortars. At all ages the compressive strength of the mortar with addition of FGD gypsum in combination with natural gypsum was higher that to other mixtures. The performances of cements prepared with mixtures FGD gypsum/natural gypsum were better compared with that prepared only with natural gypsum. At the same time, a hydration study of cements with FGD is presented. The addition of FGD gypsum increases setting time without affecting the compressive strength profile. The degree of dehydration of the dehydrated calcium sulphate regulates setting and strength performance of the cement partially replaced with either anhydrite or FGD gypsum.

In addition, gypsum will react with the tricalcium aluminate mineral (C3A), which is the compound mainly responsible for the early setting time of cement. The reaction of gypsum with (C3A) will retard the setting time of cement (i.e. prolong the setting time), which is necessary for concreting operations to be completed perfectly, if the amount of gypsum is small the setting time will be short, however, addition large amount of gypsum to the clinker during its grinding will delay the harden of the cement paste and producing a large amount of heat during the reaction and solidification of concrete. Therefore the amount of gypsum should be controlled to achieve the proper setting time and decreasing the percentage of SO3 in the concrete, and to avoid steel corrosion and concrete structure deformation.

While producing 53 grade of cement, generally cement plant prefers to use mineral gypsum. Today industry faces shortage of mineral gypsum, which is the purer form of gypsum and the gap is bridged by synthetic gypsum mainly coming from fertiliser industry. This gypsum is commonly known as chemical gypsum. Shreesh Khadilkar in his article has covered in details about various options available on sourcing gypsum. As stated by Shreesh, FGD gypsum from thermal plants can become alternate source in place of fertiliser gypsum but it is still at an experimental stage.

Handling of gypsum in a cement plant is not so easy since it is a hygroscopic material and very sticky in nature. The readers now will appreciate that though gypsum is essential ingredient of cement but proving to be a speed breaker.

VIKAS DAMLE

Continue Reading
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Economy & Market

Hindalco Buys US Speciality Alumina Firm for $125 Million

Published

on

By

Shares

This strategic acquisition marks a significant investment in speciality alumina, a key step by Aditya Birla Group’s metals flagship towards becoming future-ready by scaling its high-value, technology-led materials portfolio.

Hindalco Industries, the world’s largest aluminium company by revenue and the metals flagship of the $28 billion Aditya Birla Group, has announced the acquisition of a 100 per cent equity stake in US-based AluChem Companies—a prominent manufacturer of speciality alumina—for an enterprise value of $125 million. The transaction will be executed through Aditya Holdings, a wholly owned subsidiary.

This acquisition represents a pivotal investment in speciality alumina and advances Hindalco’s strategy to expand its high-value, technology-led materials portfolio.

Hindalco’s speciality alumina business, a key pillar of its value-added strategy, has delivered consistent double-digit growth in recent years. It has emerged as a high-growth, high-margin vertical within the company’s portfolio. As speciality alumina finds expanding applications across electric mobility, semiconductors, and precision ceramics, the deal positions Hindalco further up the innovation curve, enabling next-generation alumina solutions and value-accretive growth.

Kumar Mangalam Birla, Chairman of Aditya Birla Group, called the acquisition an important step in their global strategy to build a leadership position in value-added, high-tech materials.

“Our strategic foray into the speciality alumina space will not only accelerate the development of future-ready, sustainable solutions but also open new pathways to pursue high-impact growth opportunities. By integrating advanced technologies into our value chain, we are reinforcing our commitment to self-reliance, import substitution, and building scale in innovation-led businesses.”

Ronald P Zapletal, Founder, AluChem Companies, said the partnership with Hindalco would provide AluChem the ability and capital to scale up faster and build scale in North America.

“AluChem will benefit from their world-class sustainability and safety standards and practices, access to integrated operations and a consistent, reliable raw material supply chain. Their ability to leverage R&D capabilities and a talented workforce adds tremendous value to our innovation pipeline, helping drive market expansion beyond North America.”

An Eye on the Future

The global speciality alumina market is projected to grow significantly, with rising demand for tailored solutions in sectors such as ceramics, electronics, aerospace, and medical applications. Hindalco currently operates 500,000 tonnes of speciality alumina capacity and aims to scale this up to 1 million tonnes by FY2030.

Commenting on the development, Satish Pai, Managing Director, Hindalco Industries, said the deal reinforced their commitment to innovation and global expansion.

“As alumina gains increasing relevance in critical and clean-tech sectors, AluChem’s advanced chemistry capabilities will significantly enhance our ability to serve these fast-evolving markets. Importantly, it deepens our high-value-added portfolio with differentiated products that drive profitability and strengthen our global competitiveness.”

AluChem adds a strong North American presence to Hindalco’s portfolio, with an annual capacity of 60,000 tonnes across three advanced manufacturing facilities in Ohio and Arkansas. The company is a long-standing supplier of ultra-low soda calcined and tabular alumina, materials prized for their thermal and mechanical stability and widely used in precision engineering and high-performance refractories.

Saurabh Khedekar, CEO of the Alumina Business at Hindalco Industries, said the acquisition unlocked immediate synergies, including market access and portfolio diversification.

“Hindalco plans to work with AluChem’s high performance technology solutions and scale up production of ultra-low soda alumina products to drive a larger global market share.”

The transaction is expected to close in the upcoming quarter, subject to customary closing conditions and regulatory approvals.

 

Continue Reading

Concrete

Shree Cement reports 2025 financial year results

Published

on

By

Shares

Shree Cement posted revenue of US$2.38 billion for FY2025, marking a 5.5 per cent decline year-on-year. Operating costs rose 2.9 per cent to US$2.17 billion, resulting in an EBITDA of US$528 million—down 12 per cent from the previous year. Net profit fell 50 per cent to US$141 million. The company reported cement sales of 9.84Mt in Q4 FY2025, a 3.3 per cent increase from 9.53Mt in Q4 FY2024, with premium products making up 16 per cent of total sales.

Image source:https://newsmantra.in/

Continue Reading

Concrete

Rekha Onteddu to become director at Sagar Cements

Published

on

By

Shares

Sagar Cements has announced the appointment of Rekha Onteddu as a non-executive independent director, effective 30 June 2025. According to People in Business News, Rekha Onteddu is currently serving in a similar capacity at Andhra Cements, the parent company of Sagar Cements.

Image source:https://sagarcements.in/

Continue Reading

Trending News

SUBSCRIBE TO THE NEWSLETTER

 

Don't miss out on valuable insights and opportunities to connect with like minded professionals.

 


    This will close in 0 seconds

    This will close in 0 seconds