<p>We used solidification/stabilization methods to remediate highly concentrated Zn²⁺-contaminated soil. An industrial waste mixture of red mud, carbide slag, and phosphogypsum is combined with cement as the curing agent. The mixing ratios of the four materials are determined by comparing the strength, permeability coefficient, pH, and Zn²⁺-leaching concentration of the solidified soil. Microscopic characteristics of the solidified uncontaminated soil and solidified Zn²⁺-contaminated soil were observed using scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. Furthermore, the heavy metals speciation in both pure cement and mixed-material solidified soil was examined, demonstrating the beneficial role of the mixed-type curing agent in stabilizing heavy metals. The research results indicate that Zn²⁺ degrade the strength of the solidified soil by up to 90%. The permeability coefficient, pH, and Zn²⁺-leaching concentration of the solidified soil easily meet standard, especially with Zn²⁺ leaching concentration well below the environmental protection limit. Furthermore, most Zn²⁺ exists in forms with lower biological and chemical reactivity. Both the solidified Zn²⁺-contaminated soil and uncontaminated soil resulted in the formation of hydrated products containing elements such as silicon, aluminum, calcium, and sulfur. Additionally, the solidified Zn²⁺-contaminated soil produced zinc-containing compounds and a large amount of rod-shaped ettringite.</p>