中国有色冶金

In order to promote the resource utilization of red mud and phosphogypsum industrial solid wastes, the paper uses red mud, phosphogypsum and cementing materials (including cement, steel slag and ore slag) as raw materials to prepare composite mortar. The effect of the amount of phosphogypsum added on the phenochemical properties of the composite material was investigated. The tests showed that when the red mud dosage was 70wt%, phosphogypsum dosage was 10wt%, the 7d and 28d compression strength of the composite were 14.97MPa and 15.2MPa, respectively. By the characterization and analysis of the mineral structure and micromorphology of the composite materials by XRD, SEM-EDS, TG and FTIR, it showed that the addition of an appropriate amount of phosphogypsum could effectively fill the internal structure of the composite material and improve the mechanical properties; the addition of excessive phosphogypsum could cause formation of a large amount of ettringite, thus increasing the internal aperture of the composite, at the same time, the large enrichment of components(P and F) in phosphogypsum will reduce the mechanical properties of composite materials; the composite material could fix sodium element in the red mud through properly proportioning. The leaching test of composite materials by ICP-OES showed that the concentration of heavy metal elements in the composite leaching liquid met the III groundwater discharge standard and could be used for engineering applications.