Resource and sustainable utilization of quartz sand waste by turning into cobalt blue composite pigments

In order to realize the resource and sustainable utilization of quartz sand waste discarded from the mineral processing, Mg 2+ -doped cobalt blue composite pigments are prepared based on quartz sand via co-precipitation method followed by high-temperature crystallization. The obtained composite pigments are characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and magic angle spinning nuclear magnetic resonance. The results indicate that the incorporation of Mg 2+ ion and quartz sand improves the color properties and decreases the production cost of composite pigments, and the color can be facilely adjusted by controlling the added amount of Mg 2+ . The optimal color properties are obtained as the molar ratio of Mg 2+ to Co 2+ is 6:4, and Mg 2+ enters into the crystal lattice and occupies the tetrahedral sites of spinel cobalt blue. Therefore, this study is expected to develop feasible approach for the resource and sustainable utilization of quartz sand waste, and fabrication of low-cost bright cobalt blue composite pigments as well.