Construction and demolition waste as clinker raw material

The concept of the circular economy encourages the reuse of waste products as raw materials in the production of cement. Arthur Harrisson looks at the use of construction and demolition waste as a raw material for clinker.

Carbon dioxide is produced during cement clinker manufacture from two sources. Firstly, the primary raw material for clinker is limestone, which is predominantly calcium carbonate, CaCO₃. CaCO₃ comprises lime (CaO) and carbon dioxide (CO₂). While clinker requires a large amount of CaO, it does not require CO₂. Therefore, during the clinkering process the CO₂ is driven off and unless some means of capturing is available, it is emitted to the atmosphere.