MO.2.A || Life Cycle Approaches in the Raw Materials Sector II

Quéheille, Eva; Dauvergne, Michel; Ventura, Anne

Pyrometallurgical nickel industry in New Caledonia produces several tons of slags per year, that are stocked on site. No valorization exists today, except with a small transformation into sand. Pyrometallurgy highly consumes fossil-fuel energy and electricity for ore pre-treatment and nickel extraction inside electrical furnaces, which produces significant CO2 emissions. A new valorization approach is suggested to use these two local productions (slags and CO2) with carbon capture and utilization (CCU). By mineralizing CO2 inside slags and treating the resulted material, valuable construction products can be obtained. New Caledonia could see great socio-economical and environmental benefits : new employing sector, waste stock reduction and environmental impacts reduction. Many questions are to be answered : where to capture CO2, what mineralization rate to aim, where to sell products ? Moreover, New Caledonia aims to develop renewable energies for electrical grid, which would mitigate local industries impacts in the future. A prospective Life Cycle Assessment (LCA), featuring several scenarios and electrical grid evolution, is then realized with Brightway framework. The slag valorization sector with CCU is modelled : CO2 capture, slag preparation and mineralization, final treatments and products selling, with associated potential benefits. A sensitivity analysis enables to determine the most impactful steps of the sector and the most important scenarios factors.