Cement Sector and Promising Technologies to Reduce CO2 Footprint Through Circular Economy: Novel Raw Materials and Products

The cement sector looks for different approaches to reduce CO2 footprint. This is a requirement of regulators but also consumers are continuously demanding more sustainable materials. Accordingly, some waste residues (e.g. alternative fuels such as biomass) might be used as fuel to produce clinker. The use of alternative fuels is limited by the quality and availability of these materials, the origin largely influencing both of them. Moreover, rubbish dumped in landfills or uncontrolled sites might be used as a source of raw materials to produce clinker: coal fly and bottom ashes and slags (blast-furnace, copper, stainless steel, black, white, etc.), are rich in minerals which are essential to produce Portland cement clinker. Furthermore, some industrial wastes can be utilized as cement constituents. The use of these materials is highly interesting for this sector by allowing it to replace conventional raw materials. Nevertheless, the availability of the traditional industrial wastes used in cement production is falling (coal fly ash and blast-furnace slag). Consequently, the cement sector is looking for new sources of industrial waste to be used as cement constituents. This chapter will include innovative approaches and processes to produce clinker and Portland cement sustainably using alternative fuels and raw materials to produce clinker, and new cement constituents to reduce the clinker factor according to the target established in the cement sector’s roadmap.