Cement: Extraction
Inside the kiln that must never stop turning
What this tab covers How it is mined, drilled or grown, and processed into a tradeable form: the main methods compared, their unit economics, by-products, and the companies that do this work globally and in India.Cement starts as limestone or chalk mixed with clay or shale, quarried next to the plant. The raw meal is fed into a rotary kiln, a long steel tube that must turn without stopping. There, limestone gives up CO2 and the mix sinters into clinker. Clinker is ground with gypsum to make Portland cement, named in Joseph Aspdin's 1824 patent after Portland stone (Smil). Blended cements swap some clinker for limestone, fly ash or granulated blast-furnace slag. In 2010, China's cement industry used all available metallurgical slag (Smil).
Almost all cement is Portland or blended Portland cement, made the same basic way since Joseph Aspdin's 1824 patent. Limestone and clay are burned in a rotary kiln to make clinker, which is ground with gypsum. The main choices are kiln technology, how much clinker is replaced by fly ash, slag or limestone, and whether grinding is done at the kiln or in separate grinding units near markets. Cement is heavy and cheap, so plants serve regional markets. Kilns cost years to permit and build, so capacity responds slowly. Cement is responsible for about 7-8% of world CO2 emissions (Conway).
Methods compared
| Method | Share of supply | Typical scale | Recovery / efficiency | By-products | Unit cost |
|---|---|---|---|---|---|
| Integrated dry-process kiln plant (quarry, preheater-precalciner kiln, grinding) | the dominant route for clinker worldwide | India's industry capacity about 655 Mt at end FY2025, up from 625 Mt (UltraTech via Business Standard) | n/a | CO2 from limestone (about 60% of cement's emissions) and from fuel (about 40%) (Conway) | India Q4 FY2025 blended realisation Rs 4,779-5,555/t across major producers (JM Financial); Dalmia Bharat EBITDA Rs 820/t in FY2025; US average mill value $160/t (2025, USGS) |
| Blended cements (fly ash, slag, limestone, calcined clay) | 63% of US shipments in January-September 2025 (USGS) | India makes cement at 470 Mt with 400 Mt of clinker capacity (2025, USGS), a sign of high blending | n/a | uses waste from coal power and steel; China's cement industry used all available metallurgical slag in 2010 (Smil) | not published |
| Split grinding units and import terminals | not published globally; the US imported 23 Mt of cement and 0.66 Mt of clinker in 2025 (USGS) | Shree Cement added grinding units of 3.0 Mt/yr (Etah) and 3.4 Mt/yr (Baloda Bazar) in FY2025 | n/a | n/a | not published |
| Low-carbon and alternative cements (alkali-activated, CO2-cured) | niche | pilot and small commercial scale | n/a | n/a | not published; described as hard to make pay in a high-volume, low-margin sector (Conway) |
How each method works
Integrated dry-process kiln plant (quarry, preheater-precalciner kiln, grinding)Raw meal is preheated in cyclone towers, partly calcined, then sintered in a rotary kiln into clinker, which is cooled and ground with gypsum on site.
Lowest cost per tonne at scale; high CO2 and long build times.
Business Standard, May-June 2025; Indian PSU (Dalmia results); USGS MCS 2026; Conway (2023) Blended cements (fly ash, slag, limestone, calcined clay)Part of the clinker is replaced by fly ash (PPC), granulated blast-furnace slag (PSC) or ground limestone (Type IL), cutting kiln fuel and CO2 per tonne.
Lower cost and CO2; depends on supply of fly ash and slag as coal plants close.
USGS MCS 2026; Smil (2016) Split grinding units and import terminalsClinker is shipped from kilns to grinding units near cities or ports, where it is ground with local fly ash or slag; imported cement and clinker supply markets short of kilns.
Cuts freight on finished cement; adds a clinker logistics step.
The Week / PTI, May 2025; USGS MCS 2026 Low-carbon and alternative cements (alkali-activated, CO2-cured)Alkali-activated cements use slag without a lime kiln; CO2-cured cements such as Solidia absorb up to 240 kg of CO2 per tonne while curing in a CO2 chamber.
Large CO2 cuts; only 30-40 years of durability data vs 200 for Portland cement.
Conway, Material World (2023) Unit economics are indicative ranges from the sources named; costs vary widely by deposit, region and year.Who does it: global
| Company | Country | Activity | Volume | Year | Source |
|---|---|---|---|---|---|
| Anhui Conch Cement 2025 revenue CNY 82.5 billion, down 9.3% (Tiger Brokers news, March 2026); 2025 volume not found. | China | cement and clinker | 271 Mt cement and clinker sales | 2024 | CemNet, March 2025 (Anhui Conch 2024 results) |
| China National Building Material (CNBM) Largest producer by capacity (521 Mt/yr with Sinoma in 2018); recent volume not found. | China | cement, concrete | not published | n/a | Global Cement, July 2018 |
| Holcim Cement volume not found; 2025 net sales EUR 17.2 billion after the June 2025 spin-off of its North American business. | Switzerland | cement, aggregates, building materials | not published | 2025 | Global Cement, Feb 2026 |
| Heidelberg Materials Cement volume not found; net CO2 of 512 kg per tonne of cementitious material in 2025, down 3%. | Germany | cement, aggregates | not published | 2025 | Global Cement, Mar 2026 |
| Cemex Recent volume not found; 68.5 Mt cement sales in 2017 (Global Cement, 2018). | Mexico | cement, ready-mix | not published | n/a |
Who does it: India
| Company | Country | Activity | Volume | Year | Source |
|---|---|---|---|---|---|
| UltraTech Cement (Aditya Birla) Growth helped by acquisitions of India Cements and Kesoram. | India | cement | 136 Mt sales | FY2025 | Business Standard, May 2025 |
| Ambuja Cements and ACC (Adani) Full-year volume not found; Q4 FY2025 consolidated sales 18.7 Mt; capacity crossed 100 Mt/yr, targeting 118 Mt/yr by end FY2026; acquired Orient and Penna. | India | cement | not published | FY2025 | Business Standard, May 2025 |
| Shree Cement Full-year volume not found; Q4 FY2025 sales 9.84 Mt; capacity 62.8 Mt/yr. | India | cement | not published | FY2025 | The Week / PTI, May 2025 |
| Dalmia Bharat Installed capacity 49.5 Mt; EBITDA Rs 820/t. | India | cement | 29.4 Mt sales | FY2025 | Dalmia Bharat FY2025 results (Indian PSU) |
India is the world's second largest producer, at 470 Mt in 2025 with 400 Mt of clinker capacity (USGS). Capacity was about 655 Mt at end FY2025. The industry is consolidating around UltraTech and Adani's Ambuja-ACC. Average prices fell from Rs 375 per bag (FY2023) to Rs 365 (FY2024) and Rs 340 (FY2025) (ICRA via Business Standard).