Life Cycle Assessment of Class 1 Nickel and Nickel Sulfate Hexahydrate Production from a Northern Québec Off-Grid Nickel Sulphide Mine

Nickel is a critical material for stainless-steel production and lithium-ion battery (LIB) manufacturing, making it essential to the global energy transition. As electric vehicle adoption increases, demand for sustainably produced battery-grade nickel continues to grow. Québec hosts high-quality nickel sulphide deposits that can be refined into nickel sulfate hexahydrate (NSH), a key precursor for LIB cathodes. This study evaluates the life cycle environmental impacts of an off-grid nickel mining and processing system in Québec using a detailed, site-specific inventory covering mining, concentration, smelting, refining, and NSH production. Two product systems were assessed: (1) Class 1 nickel, with a functional unit of 1 tonne of refined nickel at the refinery gate, and (2) NSH, with a functional unit of 1 tonne of NSH at the plant gate. The NSH system extends the Class 1 nickel boundary to include the additional processing required to produce battery-grade NSH. The life cycle assessment (LCA) shows that the mine, concentrator, smelter, and refinery generate 17.06 t CO2-eq per tonne of Class 1 nickel (long-term, no co-product credits) and 14.05 t CO2-eq per tonne with co-product credits. Extending the system boundary to NSH production increases emissions to 20.10 and 18.48 t CO2-eq per tonne of NSH, respectively. Despite the challenges of remote off-grid operations, Québec-based NSH production shows lower long-term climate impacts than comparable operations in Indonesia and China. Sensitivity analysis indicates that replacing diesel with natural gas could reduce CO2 emissions on-site combustion emissions of CO2 by approximately 28%, highlighting the influence of site-specific energy systems and the importance of decarbonization strategies, including renewable energy integration, for critical mineral production.