Chapter 7. Integrating Remediation and Resource Recovery of Industrial Alkaline Wastes: Case Studies of Steel and Alumina Industry Residues

With an estimated annual production of two billion tonnes globally, alkaline industrial wastes can be considered both major global waste streams, and materials that offer significant options for potential resource recovery. Alkaline wastes are usually derived from high temperature production (e.g. steel and alumina) or disposal (e.g. incineration) processes and are increasingly abundant given rising global demand for steel and alumina and the drive for waste incineration in some jurisdictions. Although relatively long-standing afteruses have been adopted for these materials providing opportunities for value recovery (e.g. steel slag use as an aggregate), they are not sufficient to consume all residues generated or completely limit potential environmental impacts. These impacts can include the generation of fugitive dusts, challenges associated with revegetation, and effects on the water environment. These wastes can produce highly alkaline leachates enriched with trace metals (e.g. As, Cr, Mo, V) and persist over decades after site closure. Vanadium, one of the most hazardous ecotoxins in leachates, is also a valuable commodity for renewable energy technologies, unifying the often divergent needs of resource recovery and remediation. Case studies are included to illustrate routes to resource recovery from wastes from two major industrial sectors: steel production and alumina production.