Pge production in Southern Africa, part II: Environmental aspects

Platinum group elements (PGEs, 6E PGE = Pt + Pd + Rh + Ru + Ir + Au) are used in numerous applications that seek to reduce environmental impacts of mobility and energy generation. Consequently, the future demand for PGEs is predicted to increase. Previous studies indicate that environmental impacts of PGE production change over time emphasizing the need of up-to-date data and assessments. In this context, an analysis of environmental aspects of PGE production is needed to support the environmental assessment of technologies using PGEs, to reveal environmental hotspots within the production chain and to identify optimization potential. Therefore, this paper assesses greenhouse gas (GHG) emissions, cumulative fossil energy demand (CED_fossil), sulfur dioxide (SO₂) emissions and water use of primary PGE production in Southern Africa, where most of today’s supply originates from. The analysis shows that in 2015, emissions amounted to 45 t CO₂-eq. and 502 kg SO₂ per kg 6E PGE in the case GHG and SO₂ emissions, respectively. GHG emissions are dominated by emissions from electricity provision contributing more than 90% to the overall GHG emissions. The CED_fossil amounted to 0.60 TJ per kg 6E PGE. A detailed analysis of the CED_fossil reveals that electricity provision based on coal power consumes the most fossil energy carriers among all energy forms. Results show that the emissions are directly related to the electricity demand. Thus, the reduction in the electricity demand presents the major lever to reduce the consumption of fossil energy resources and the emission of GHGs and SO₂. In 2015, the water withdrawal amounted to 0.272 million L per kg 6E PGE. Additionally, 0.402 million L of recycled water were used per kg 6E PGE. All assessed indicators except ore grades and production volumes reveal increasing trends in the period from 2010 to 2015. It can be concluded that difficult market conditions (see part I of this paper series) and increasing environmental impacts present a challenging situation for the Southern African PGE mining industry.