Preparation of Micro-Iron Ore Tailings by Wet-Grinding and Its Application in Sulphoaluminate Cement

Herein, micro iron ore tailings(micro-IOTs) were prepared by wet-grinding and applied to improve sulphoaluminate cement (SAC) performance. The physicochemical properties of micro-IOTs were investigated by particle size analysis, XRD, and XPS. The hydrates trait and the hydration mechanism of micro-IOTs-SAC composite were studied by XRD, TGA, MIP, and SEM. The results demonstrated that micro-IOTs with an average grain diameter of 517 nm could be obtained by wet-grinding. The setting time of SAC gradually decreased with increasing micro-IOTs content. By adding 2% micro-IOTs, the compressive strengths of SAC pastes were enhanced about 22% and 10% at 4 h and 28 d, respectively. Moreover, the addition of micro-IOTs accelerated ettringite precipitation and changed its morphology, resulting in early strength improvement of the binary system. And increased later strength by micro-IOTs was closely related to the high content of AH(3), fine pore structure, and high hydration degree of SAC. The findings suggested one new approach to utilize iron ore tailings in cement-based materials.