To address the high carbon emissions and resource dependency associated with conventional ordinary Portland cement (OPC) production, this study systematically investigated the preparation processes, hydration mechanisms, and chemical properties of high-belite calcium sulfoaluminate (HBCSA) and calcium sulfoaluminate (CSA) cements based from industrial solid wastes. The results demonstrate that substituting natural raw materials (e.g., limestone and gypsum) with industrial solid wastes—including fly ash, phosphogypsum, steel slag, and red mud—not only reduces raw material costs but also mitigates land occupation and pollution caused by waste accumulation. Under optimized calcination regimes, clinkers containing key mineral phases (C₄A₃S⁻ and C₂S) were successfully synthesized. Hydration products, such as ettringite (AFt), aluminum hydroxide (AH₃), and C-S-H gel, were identified, where AFt crystals form a three-dimensional framework through disordered growth, whereas AH₃ and C-S-H fill the matrix to create a dense interfacial transition zone (ITZ), thereby increasing the mechanical strength. The incorporation of steel slag and granulated blast furnace slag was found to increase the setting time, with low reactivity contributing to reduced strength development in the hardened paste. In contrast, Solid-waste gypsum did not significantly differ from natural gypsum in stabilizing ettringite (AFt). Furthermore, this study clarified key roles of components in HBCSA/CSA systems; Fe₂O₃ serves as a flux but substitutes some Al₂O₃, reducing C₄A₃S⁻ content. CaSO₄ retards hydration while stabilizing strength via sustained AFt formation. CaCO₃ provides nucleation sites and CaO but risks AFt expansion, degrading strength. These insights enable optimized clinker designs balancing reactivity, stability, and strength.

Solid waste-based cementitious materials (SWCMs) represent an innovative class of binders derived mainly from construction and demolition waste as well as industrial byproducts. Their application in recycled mortar offers a promising pathway to partially replace conventional cement, thereby advancing resource recycling and facilitating a low-carbon transition in the cement industry. This review systematically examines the properties, activation techniques, strength development, and corrosion resistance of recycled mortar prepared with SWCMs. Recycled powder (RP) and industrial solid waste have gelation potential, but their low reactivity requires activation treatment to enhance utilization efficiency. Activation methods, including thermal activation, carbonation, and alkali activation, effectively enhance reactivity and promote the formation of dense gel structures (e.g., C-(A)-S-H, N-A-S-H). While low replacement ratios optimize pore structure via the microfiller effect, higher ratios introduce excessive inert components, impairing mechanical properties. SWCMs demonstrate superior resistance to sulfate and chloride attacks, but their acid resistance is relatively limited. They also have excellent freeze–thaw resistance. SWCMs represent a viable and sustainable alternative to conventional cement, exhibiting commendable mechanical and durability properties when properly activated and formulated, thereby contributing to resource recycling and environmental sustainability in the cement industry.