Life cycle assessment of ferronickel production in Greece

摘要

Ferronickel (FeNi) is predominantly produced from nickeliferous laterite ores which are converted into a product with a nickel content of around 20%. With increasing emphasis being put on energy efficiency and global climate change, it is important for the nickel industry to further explore energy saving issues and to evaluate a number of potential opportunities for reducing the greenhouse gas footprint of primary FeNi production. This study adopted a life cycle assessment (LCA) approach to assess energy consumption and greenhouse gas footprints of the main processing stages of a typical Greek nickel laterite ore. In this context, a detailed life cycle directory was created based on facility-specific data and used for a holistic cradle-to-gate LCA analysis (including mining and the main ore processing routes) using the GaBi 6 software package and specific related databases. The following energy and environmental indicators were assessed: GWP (global warming potential), AP (acidification potential) and PED (primary energy demand). Using current FeNi production as a baseline scenario, two alternative scenarios, namely (i) the Green Energy scenario that involves 50% substitution of fossil fuels mix (lignite and coal) with biochar and 50% substitution of lignite with renewable resources for electricity production, and (ii) the Waste Utilization scenario that includes 85% utilization of slag in the construction sector, to improve energy and waste utilization, minimize the adverse environmental impacts and therefore achieve more sustainable FeNi production were investigated. Results showed that for the baseline scenario the largest share for both renewable and non-renewable primary energy consumption (-80 %) as well as for most environmental impacts were attributed to the stages of smelting and refining mainly due to the consumption of electricity and thermal energy. The best alternative scenario for energy savings and reduction of associated GHG emissions during FeNi production was the Green Energy scenario. With this scenario energy savings and GHG emissions were about 17% and 35% lower compared to the baseline scenario, respectively. Lower reduction in energy consumption (7%) and GHG emissions (13%) compared to the baseline scenario was attained when the Waste Utilization scenario was considered.