Life cycle assessment of nickel products

Purpose

To support the data requirements of stakeholders, the Nickel Institute (NI) conducted a global life cycle impact assessment (LCIA) to show, with indicators, the potential environmental impacts of the production of nickel and ferronickel from mine to refinery gate. A metal industry wide agreed approach on by-products and allocation was applied.

Methods

Nine companies, comprising 19 operations, contributed data, representing 52 % of global nickel metal production and 40 % of global ferronickel production. All relevant pyro- and hydrometallurgical production routes were considered, across most major nickel-producing regions. Data from Russia, the biggest nickel-producing nation, was included; the Chinese industry did not participate. 2011 was chosen as reference year for data collection. The LCIA applied allocation of impacts of by-products using both economic and mass allocations. A sensitivity analysis was conducted to further understand the relevance and impact of the different allocation approaches.

Results and discussion

The primary extraction and refining steps are the main contributors to primary energy demand (PED) and global warming potential (GWP), contributing 60 and 70 % to the PED for the production of 1 kg class I nickel and 1 kg nickel in ferronickel, respectively, and over 55 % of the GWP for both nickel products. The PED for 1 kg class 1 nickel was calculated to be 147 MJ, whilst the PED for 1 kg nickel in ferronickel was calculated to be three times higher at 485 MJ. The main factors influencing energy demand in the metallurgical processes are ore grade and ore mineralogy. Sulphidic ore is less energy intensive to process than oxidic ore. Eighty-six percent of the production volume from class 1 nickel producers, in this study, is from sulphidic ore. All ferronickel was produced from oxidic ore. The LCIA results, including a sensitivity analysis of the impact of producers with higher and lower PED, reflect the influence of the production route on energy demand and on environmental impact categories.

Conclusions

Conformant to relevant ISO standards, and backed-up with a technical and critical review, this LCIA quantifies the environmental impacts associated with the production of the main nickel products. With this study, a sound background dataset for downstream users of nickel has been provided. The Nickel Institute aims to update their data in the coming years to reflect upon changes in technology, energy efficiency, and raw material input.