"Cement is the indispensable component of concrete, and **it is produced by heating** (to at least 1,450ºC) **ground limestone** (a source of calcium) **and clay, shale, or waste materials** (sources of silicon, aluminum, and iron) **in large kilns**—long (100–220 meters) inclined metal cylinders. **This high-temperature sintering produces clinke**r (fused limestone and aluminosilicates) **that is ground to yield fine, powdery cement**." ([Location 1912](https://readwise.io/to_kindle?action=open&asin=B08SGC3TD3&location=1912)) --- **Tags** -- [[quotes]], [[cement]], [[concrete]], [[clinker]], [[limestone]], **Source** -- [[202412030828 - B - How the World Really Works]]