Belite cement clinker from autoclaved aerated concrete waste fines with high sulfate content

Abstract The processing of belite cement clinker in a rotary kiln at about 1000°C CO 2 atmosphere is new recycling option for Autoclaved Aerated Concrete (AAC) waste that otherwise must be landfilled. Waste fine fractions from sorting facility enriched sulfate due to intermixing with plaster have been processed. During clinkering the phase (Ca SiO 4 ) besides technical ellestadite, 10 (SiO 3 (SO Cl ), or ternesite, 5 SO are formed, depending on addition flux minerals. However, not all phases novel react hydraulically. Whereas ternesite reacts water, ellestadite forms complex solid solution series (Ca/Pb, /PO which may used as an insoluble reservoir mineral undesirable constituents, such phosphates and chlorides. produced has successfully partially substitute OPC AAC production trials. quantities landfill costs minimized, while same time, emissions primary resource consumption reduced. Joint work industrial companies underway increase technology readiness. Particularly large reduction effects can achieved through electrical heating kiln.