A study investigated the solidification/stabilization of chromium (Cr) in red mud-based geopolymers. Up to 1.5 wt% of Cr(III) salts (CrCl₃, Cr₂O₃) and Cr(VI) salts (Na₂CrO₄, CaCr₂O₇) were incorporated into red mud-based geopolymers. The results showed that the red mud-based geopolymer could effectively solidify/stabilize different types of Cr salts with solidification/stabilization rates above 99.61%. Geopolymers are environmentally safe when the dosage of CaCr₂O₇ is ≤1.0 wt% or the dosage of CrCl₃, Cr₂O₃, and Na₂CrO₄ is ≤1.5 wt%. The effects of Cr salts on compressive strength varied with the type and content of Cr salts. Freeze-thaw cycles were more destructive to geopolymer properties than sulfate attack or acid rain erosion. The solidification/stabilization of Cr was mainly attributed to chemical binding of Cr through the formation of Cr-containing hydrates and doping into N-A-S-H and C-A-S-H gels, and physical effects through encapsulation by hydration products. This study provides a reference for the treatment of hazardous Cr-containing wastes using solid waste-based geopolymers. The study also highlights the importance of evaluating the durability of Cr-containing geopolymers under different corrosion conditions, as corrosion can disrupt mechanical properties and lead to structural damage and heavy metal leakage. The geopolymer matrix was prepared with red mud and ground granulated blast furnace slag (GBFS) in a 5:5 ratio. The activator was sodium silicate solution with a modulus of 1.40. The study explored the Cr solidification/stabilization capacity and mechanical properties of the geopolymers, as well as their durability under different corrosion conditions. The hydration process and microscopic structure of the geopolymer were characterized by XRD, FTIR, and BET analyses. The results indicated that the red mud-based geopolymer could effectively solidify/stabilize Cr salts, with high durability under various corrosion conditions.A study investigated the solidification/stabilization of chromium (Cr) in red mud-based geopolymers. Up to 1.5 wt% of Cr(III) salts (CrCl₃, Cr₂O₃) and Cr(VI) salts (Na₂CrO₄, CaCr₂O₇) were incorporated into red mud-based geopolymers. The results showed that the red mud-based geopolymer could effectively solidify/stabilize different types of Cr salts with solidification/stabilization rates above 99.61%. Geopolymers are environmentally safe when the dosage of CaCr₂O₇ is ≤1.0 wt% or the dosage of CrCl₃, Cr₂O₃, and Na₂CrO₄ is ≤1.5 wt%. The effects of Cr salts on compressive strength varied with the type and content of Cr salts. Freeze-thaw cycles were more destructive to geopolymer properties than sulfate attack or acid rain erosion. The solidification/stabilization of Cr was mainly attributed to chemical binding of Cr through the formation of Cr-containing hydrates and doping into N-A-S-H and C-A-S-H gels, and physical effects through encapsulation by hydration products. This study provides a reference for the treatment of hazardous Cr-containing wastes using solid waste-based geopolymers. The study also highlights the importance of evaluating the durability of Cr-containing geopolymers under different corrosion conditions, as corrosion can disrupt mechanical properties and lead to structural damage and heavy metal leakage. The geopolymer matrix was prepared with red mud and ground granulated blast furnace slag (GBFS) in a 5:5 ratio. The activator was sodium silicate solution with a modulus of 1.40. The study explored the Cr solidification/stabilization capacity and mechanical properties of the geopolymers, as well as their durability under different corrosion conditions. The hydration process and microscopic structure of the geopolymer were characterized by XRD, FTIR, and BET analyses. The results indicated that the red mud-based geopolymer could effectively solidify/stabilize Cr salts, with high durability under various corrosion conditions.