Metal mine tailings (MMT) are a kind of industrial solid waste, with an increasing accumulation year by year, which has seriously damaged the ecological environment. Incorporating MMT in ultra-high performance concrete (UHPC) is an effective means to achieve green sustainable development, which can not only make wastes be resources and prevent pollution but also save raw material costs and reduce energy consumption. However, metal mine tailings contain complex and diverse metal oxides and other chemical substance and even contain certain radioactive elements and heavy metal ions. These factors can affect the corrosion resistance of UHPC, accelerate its aging and damage, and in addition may have serious impacts on the environment and human health. This paper summarizes the material properties of MMT and its application in UHPC; analyzes the effects of MMT as powder or fine aggregate on the workability, mechanical properties, durability, and leaching toxicity of UHPC; and elaborates the hydration products, interfacial transition zone, and pore structure of UHPC incorporating MMT (MMT-UHPC). Based on previous research results, the relationship between flowability, flexural strength, porosity, and compressive strength of MMT-UHPC is established.

Ca leaching from steel-making slag (SS) has been widely used to obtain Ca-rich solutions for CO₂ mineralization and calcium carbonate production, but the reutilization of the resulting solid residues remains insufficiently addressed. In this study, the effects of partially replacing cement with acetic acid-dissolved residue (HDR) or NH₄Cl-dissolved residue (NDR) on mortar performance were evaluated. XRD analysis showed that Ca leaching altered the mineral assemblages of both residues, with the depletion of several Ca-bearing phases and the relative retention of Ca₂(Al,Fe)₂O₅ and the RO phase. The mechanical performance of the residue-containing mortars depended on the residue source and replacement ratio. Low-to-moderate replacement levels retained useful compressive and flexural strengths, whereas excessive replacement reduced strength development. Appropriate incorporation of HDR or NDR maintained favorable sulfate-resistance coefficients, while 10–20% NDR improved freeze–thaw resistance. Calorimetry and microstructural observations showed that Ca-leached residues affected hydration heat evolution and the morphology of gel-like hydration products, while cement dilution and limited residue hydration contributed to the early-age strength loss at high replacement levels. These findings demonstrate the feasibility of reutilizing Ca-leached SS residues as partial cement replacements, provided that the replacement level is selected according to the required mechanical and durability performance of the mortar.