Valorization of Treated Spent Potlining in Cement Industry

Spent potlining (SPLSpent Pot Lining (SPL)) is a hazardous waste produced by aluminumAluminum smelters. It is classified as a hazardous waste due to its contamination with fluoridesFluoride and cyanidesCyanide and its reactivity with water, generating explosive gases. After being industrially and hydrometallurgically treated by the Low Caustic Leaching and Liming (LCL&L) process, the refractory part of SPLSpent Pot Lining (SPL) becomes an inert, non-hazardous material, called LCLL Ash. The cement industry is a major emitter of greenhouse gases. One of the best options for reducing the carbon footprintCarbon footprint of concrete is the use of supplementary cementitious materials or fillers to replace part of the cement in the concrete. This article presents the conditions that make LCLL Ash a suitable and value-added material for the cement industry. The results presented were obtained over the past four years as part of an R&D project at the Ecole de Technologie Superieure (Montreal) and UniversiteUniversities Laval (Quebec), with the support of Rio Tinto and Ciment Quebec.