Gavin M. Mudd works at the Environmental Engineering, Department of Civil Engineering, Monash University, CLAYTON, Victoria, Australia 3800 (Gavin.Mudd@eng.monash.edu.au)
“A major concern with this increasing proportion of laterite nickel is that, although technology such as HPAL now exists to make processing of laterite ores more viable (technically and financially), it is widely perceived to be at a higher environmental cost.” (Gavin M. Mudd – 2009)
There are widespread nickel resources around the world, but divided principally between nickel sulfide or laterite (oxide) resources. Historically production has been dominated by sulfide ores but future production is increasing shifting to laterite ores. The principal reason for this historically is that sulfide ores are easier to process, through conventional mining, smelting and refining, compared to laterite ores which require intensive hydrometallurgical processing (such as high pressure acid leaching or HPAL).
This means that laterite ores typically require substantially more energy and chemicals to produce than sulfide nickel. Given that many major nickel companies report annually on their sustainability performance, such as Eramet, Inco (now Vale Inco), WMC Resources (now BHP Billiton), Norilsk Nickel, there is data available to examine in detail the differences in the environmental costs of nickel sulfide versus laterite.
The paper compiles and analyses a range of data, showing the higher energy costs of laterite projects, but also the critical importance that energy sources can have on overall environmental costs. Given that the world is continuing to demand nickel, and most uses are somewhat dissipative which limit high rates of recycling, the progressive shift to nickel laterite projects in the global nickel industry is perhaps inevitable, but it will clearly come at higher environmental costs for nickel production.
Based on present technology and research, there appears little hope for any alternatives which might significantly reduce the environmental costs of nickel laterite projects. The big sustainability challenges such as energy and greenhouse emissions therefore remain of paramount importance to the nickel sector.
For the full report, please go to the following link: http://users.monash.edu.au/~gmudd/files/2009-CMS-01-Nickel-Sulf-v-Lat.pdf