Eco-efficiency in primary metals production: Context, perspectives and methods

Sustainability's imperative of economic development in tandem with social advancement and environmental protection is widely accepted, but much debate remains about its practical implications for the products, materials and technologies of the future. A sustainable development perspective on current patterns of metals use and reuse reveals competing goals. Creating greater intra-generational equity in social and economic opportunity will increase the global stock of metals in use, through primary metals production, which could threaten environmental sustainability. The sustainable development agenda for metal production and use is therefore multifaceted, including dematerialisation, design for disassembly and recycling, optimisation of end-of-life product recovery and recycling systems, and environmental innovations in primary metals production. Upon consideration of this context, opportunities for environmental innovations in primary metals production are focused upon here, for which eco-efficiency (EE) provides the starting point.The paper provides both environmental sustainability and operational perspectives on the application of EE in primary metals production. The environmental sustainability perspective is clarified using a hierarchy of sustainability principles, from the fundamentals of ecological systems to operational practices and metrics for businesses, which justifies a focus on EE at the firm level. Earlier attempts to define EE and related concepts for primary metals production are briefly reviewed, leading to an integrated framework. This connects five ‘prevention practices’ (process design; input substitution; plant improvement; good housekeeping; reuse and recycling) with five ‘resource productivity themes’ (resource efficiency; energy use and greenhouse gas emissions; water use and impacts; control of minor elements and toxics; by-product creation). EE methods are then outlined as they apply to continuous improvement of existing operations and in the realisation of major projects. It is concluded that EE is an important milestone on the sustainable development journey for primary metals production.