Abstract: A method for solid-phase activation and neutralization of bauxite refinery residue (“red mud”) comprises the steps of preparing a quantity of untreated red mud having a moisture content of approximately 15 percent by weight, introducing a quantity of at least one reagent, and mixing in a mixer the quantity of untreated red mud and the quantity of at least one reagent. The mixing step is adapted to expose reaction sites at the nano-particle level. In one embodiment, the at least one reagent is calcium chloride and magnesium chloride salts. In another embodiment, an acid is introduced to the quantity of untreated red mud and the quantity of at least one reagent. A neutralized and activated red mud formed by the process is suitable for heavy metals remediation in soil and water.