Environmental impact assessment of valuable heavy minerals production through sand separation processes using life cycle assessment

• LCA of mineral sand separation plant based on real operation in Australia conducted. • Economic and mass impact allocation assessed for the main products. • Producing 1 tonne of zircon-rich concentrate consumes 541.7 MJ energy, 0.63 kL water. • 41.1 kg CO 2 -e and 0.12 t waste footprint per tonne of zircon-rich concentrate. Heavy Mineral Sand (HMS) deposits, as the source for critical minerals, have gained increasing attention as viable sources for producing various sand-based mineral products, due to the rising demand from markets. However, energy consumption patterns and potential environmental impacts are yet to be evaluated for mineral sand production routes. This study is a gate-to-gate Life Cycle Assessment (LCA) which aimed to evaluate the Energy, Carbon, Water, and Waste (ECWW) footprint of a heavy mineral separation processing technology. The Life Cycle Inventory (LCI) was developed using real operational data from an active HMS separation plant in Australia and modelled in SimaPro 9.5 using the ReCiPe midpoint method for impact assessment. The results demonstrate that producing 1 tonne of zircon-rich concentrate results in ECWW footprints of 541.7 MJ, 41.1 kg CO 2 −e, 0.63 kL of freshwater, and 0.12 tonnes of solid waste when mass allocation is adopted. However, these figures double when the impacts are assessed using an economic allocation. During the main separation process, conducted through Rare Earth Rolls (RERs) and High-Tension Rolls (HTRs), the primary energy-consuming process units are the dryers and reheaters, which are integral to the feed preparation stages prior to separation. These findings emphasize the importance of addressing energy use during the feed preparation stage to achieve significant reductions in the overall environmental footprint. Sensitivity analysis on energy transitioning indicates that a shift toward greater reliance on renewable energy has strong potential to lower environmental impacts; however, practical implementation depends on site-specific practically feasible energy sources.