Strengthening effect and mechanism of titanium extraction slag on the mechanical property of calcium aluminate cement

In heavy oil recovery, calcium aluminate cement (CAC) is in the working environment of "low-temperature hardening and ultrahigh temperature service." However, the formation of C3AH6 under low temperatures results in a decrease in strength and reduce the cementing quality. In this study, titanium extraction slag (TES) was used to inhibit CAC strength deterioration. TES, characterized by a high Ti content, presents challenges in terms of utilization and poses significant ecological risks owing to its large accumulation. Cementite hydration with 0%, 20%, 30%, and 40% TES relative to CAC was examined at 30 degrees C for 28 d. The high C3AH6 content of the pure CAC increased the strength deterioration, pore size, and cementite carbonation. With 20% TES, a dilution effect was observed without strength improvement. Furthermore, 30% TES generated layered double hydroxides and converted C-S-H into C-A-S-H, thereby increasing compressive strength. By-products were generated with 40% TES, which inhibited the strength development while generating C-A-S-H to maintain the compressive strength. Therefore, TES can inhibit the strength decline of CAC, and the byproducts of the LDH structure can improve corrosion resistance.