Environmental assessment of base metal processing: a nickel refining case study

The processing of mined and beneficiated ores, concentrates or mattes to produce refined metallic products is an important step in the production of base metals such as zinc, copper and nickel. Despite increased recycling, as well as first tentative steps towards dematerialization of economic activity in industrialized countries, prospects are positive for continued growth in demand for these commodities (see, e.g. Williamson1). However, it is nowadays generally accepted that the extraction and processing of such resources has to be managed in a socially and environmentally responsible manner. Petrie and Raimondo2 have argued that improvements in environmental performance, whilst mostly driven by concerns expressed by society, can ultimately be effected only by the operating companies themselves. To this end, companies have to make use of technology change in a wider sense, extending beyond simple hardware choice to also include changes to operating and management practice. One of the consequences of these realizations is the widespread adoption and implementation of Environmental Management Systems in many industries, including the mining and metallurgical sectors. Systems such as those based on the ISO 14000 standards by themselves do, however, offer little in the way of technical guidance to companies intent on improving their environmental performance. Consequently, the question often faced by management and technical staff is how an environmental assessment can be carried out so as to form the cornerstone for meaningful advances in this area. Risk assessments of varying detail may be used for this purpose. However, the potential exists for emphasis to be placed on the most obvious, end-of-pipe aspects of a company’s operations, which may in fact not always result in the most environmentally meaningful improvements. Life cycle assessment provides a broader view by generating a model which links the industry to be assessed through all its material and energy resource flows to other environmentally significant processes in the wider industrial network. At the same time a well-defined process life-cycle model retains the power to relate potential environmental liability directly to specific unit operations in the industry which is being assessed. This paper reports on a process-based life cycle assessment which was performed for the Environmental assessment of base metal processing: a nickel refining case study