As concerns economics, it depends on too many (local) factors to give a proper answer. The Red Mud has considerable acid neutralizing capacity of up to 4 moles per kg at the pH 5.5 of maximum chromate adsorption capacity. Leached concentrations of metal(oid)s at that pH remain well below European limit concentrations for inert (waste) solids. You may find some publications on: https://www.researchgate.net/profile/JJP_Hans_Zijlstra2/timeline/publications
Published by J.J.P. (Hans) Zijlstra, Director at GeoChemTec
As concerns economics, it depends on too many (local) factors to give a proper answer. The Red Mud has considerable acid neutralizing capacity of up to 4 moles per kg at the pH 5.5 of maximum chromate adsorption capacity. Leached concentrations of metal(oid)s at that pH remain well below European limit concentrations for inert (waste) solids. You may find some publications on: https://www.researchgate.net/profile/JJP_Hans_Zijlstra2/timeline/publications