'Wollastonite-modified sulfur cement- synthesis, properties, and recycling potential

This study presents a novel variant of modified sulfur cement incorporating wollastonite. The wollastonite-enhanced sulfur cement was fabricated through processes including mixing, milling, and thermal treatment. The specimens underwent mechanical testing and were analyzed utilizing XRD, SEM, EDS, and XPS. The mixture was heated to 170 °C for 1 hour, then cooled to ambient temperature. It was observed that the addition of 35 wt.% wollastonite significantly improved both flexural and compressive strengths. XRD and XPS analyses demonstrated that the inclusion of wollastonite did not alter the phase composition, resulting in a wollastonite–sulfur micro-composite. This composite remains fully recyclable and is appropriate for producing sulfur cement with comparable mechanical properties. It has been found that wollastonite inhibits the formation of large orthorhombic sulfur crystals and promotes the formation of a nanocrystalline sulfur matrix that functions as a binder, thereby reducing localized shrinkage. This research is significant because it enables the production of high-strength sulfur cement without chemical additives, paving the way for a novel mineral-powder-based modified sulfur cement.