Alternative raw materials
One way for Lafarge to emit less carbon dioxide (CO2) is to use alternative raw materials to replace limestone in the manufacture of cement. Derived from natural or industrial sources, such alternatives have the same properties as clinker, the main ingredient in conventional cement.
Cement manufacturing generates large amounts of CO2 during a physical-chemical process called "decarbonation". In this process, limestone is heated to very high temperatures to produce clinker, which then is ground down to produce cement.
However, the amount of clinker required can be reduced by substituting alternatives called cement admixtures.
Reducing the amount of clinker in cement offers two advantages:
Cement admixtures may be:
Lafarge takes a proactive approach to the use of alternative raw materials, consuming 21 million tons of industrial admixtures each year, with volume growing by 9% annually.
Slag in steel plant