Calcium sulfoaluminate cements are widely used as special cements and, because of their low specific carbon dioxide emissions relative to those of Portland cement, they have potential for use in general construction. However, their widespread application has been limited by the relatively high cost of aluminous raw materials. As part of a broad programme on the optimisation of these cements, the clinker mineralogy was reformulated to enhance the activity and strength contribution of the silicate phases. Preservation of the α′ dicalcium silicate phase to ambient is described in this paper. Commercially available raw materials and reagent-grade chemicals were used and clinker syntheses were conducted. Preservation of the α-belite phase to ambient temperature was achieved by a combination of chemical doping with control of the furnace atmosphere and fast cooling of the clinker. A clinker with α′-belite, ye'elimite and ferrite can be optimised to create a new generation of low-cost sulfoaluminate cements with improved performance and large potential energy savings relative to Portland cement.

Belite–ye’elimite–ferrite (BYF) cement has garnered significant interest as an alternative to ordinary Portland cement (OPC) due to its lower limestone content, early-age strength development and improved durability. However, the main challenge to the commercial production of BYF cement is the requirement for large quantities of costly aluminous raw materials. The introduction of alpha prime belite (α′ C₂S) to BYF clinker would minimize production costs while maintaining mechanical properties. Herein, α′ C₂S containing BYF clinkers were synthesized and analysed to determine their properties and hydration characteristics. The clinker samples were synthesized using a previously reported clinkering technique wherein a sulfur-containing atmosphere was used, with a raw mix design including additions of a combination of boron, potassium and sodium-containing doping agents. Preliminary data showed adequate amounts of α′ C₂S were preserved, reaching more than 40 wt% of total clinker composition. Moreover, the heat release curves revealed enhanced hydration kinetics for the modified clinkers compared to the unmodified ones. While there was a noticeable improvement in ettringite precipitation upon hydration, the precipitation of strätlingite remained the same after doping. The experimental findings showed high potential for the existence of low-ye’elimite BYF clinker formulations as part of the wider portfolio of OPC clinker alternatives.