Continuous production of alinite in a laboratory-scale rotary kiln

Alinite cement was firstly patented in the USSR in 1970s and their performance is comparable to that of Portland cement. Interest in alinite cement for general use has since waned due to the inclusion of chloride which is known to exacerbate corrosion in reinforced concrete; however, alinite cement may have roles as application-specific cements. Alinite is a structural variant of alite (Ca3SiO5) with substitution with Cl, Mg, and Al ions; it allows for a reduced carbon footprint than alite, given the lower sintering temperature required for its synthesis. In addition, the chemistry of alinite allows for

the beneficial use of Cl and Mg containing wastes for its production. In this work, upscaling of the calcination procedure was studied for production of alinite in a continuous laboratory-scale rotary kiln, with different residence times. The quantitative X-ray diffraction analysis, employing the Rietveld method, showed that the products achieved alinite contents of 25-37 wt.%, with no significant effects observed for the different sintering times. The smaller alinite composition in the products, in comparison with small laboratory crucible scale, suggest that the atmosphere in the kiln may have a strong influence on the formation of alinite.