Intermediate Topic 1080 of 1102 Biochemistry, Environment & Industry

Cement Manufacture

Limestone and clay are heated in kilns to form clinker.

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In-depth explanation of Cement Manufacture

Cement is the powdered binder used in concrete, most commonly Portland cement. Limestone and clay are ground and blended, then heated in a rotary kiln to about 1450 C, where they react to form clinker, mainly calcium silicates. Calcination releases CO2 from the limestone, since CaCO3 gives CaO plus CO2, which makes cement production a major source of global emissions. The clinker is cooled and ground with gypsum to control the setting time. Blended cements, alternative fuels and carbon capture are used to reduce its carbon footprint.

Going deeper: Cement Manufacture

Key ideas: Limestone (CaCO3) and clay are heated in a kiln to about 1450 C, forming clinker (Ca3SiO5, Ca2SiO4, Ca3Al2O6) after CaCO3 decomposes to CaO plus CO2. Clinker is ground with about 5 percent gypsum to slow setting. Hydration of silicates gives calcium silicate hydrate gel plus Ca(OH)2. Concrete equals cement plus sand plus aggregate plus water.

Common mistakes and connections: Mistake: saying cement dries; it sets by hydration chemical reaction and even works underwater. Cement is the binder, concrete the mix. About 0.9 tonne CO2 emitted per tonne, half from calcination itself, so fuel switching alone cannot decarbonize. Links to thermal decomposition and carbon capture.

Visualization of Cement Manufacture

Calcination, CaCO3 to CaO + CO2, loses 44 percent of the limestone mass as carbon dioxide, a major source of cement emissions. The interactive lesson shows this as a live animation or chart.

Worked example and use case

Roughly 0.6 tonne of CO2 is released for each tonne of Portland cement produced.

Frequently asked questions about Cement Manufacture

What is Cement Manufacture?

Limestone and clay are heated in kilns to form clinker.

Is Cement Manufacture a beginner, intermediate or advanced topic?

Cement Manufacture is a intermediate topic in Biochemistry, Environment & Industry. It builds on the vocabulary of beginner topics in this area.

What should I learn before Cement Manufacture?

Study these earlier topics in Biochemistry, Environment & Industry first: Paper Industry, Soap Making, Glass Manufacture.

What comes after Cement Manufacture?

The next topics in Biochemistry, Environment & Industry are Fertilizer Production and Explosives.

Can I practise Cement Manufacture with quizzes?

Yes. The interactive lesson includes a self-check question on Cement Manufacture, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.

Where Cement Manufacture fits in Biochemistry, Environment & Industry

Cement Manufacture is topic 105 of 127 in Biochemistry, Environment & Industry.