Achieving environmental stewardship in iron and steel sector through application of life cycle assessment

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The aims of this thesis are: (1) To develop improved knowledge and understanding of material flows and life cycle assessments of the iron and steel industries and (2) suggest policy directions based on the knowledge and understandings gained. It is hoped that improved environmental performance and environmental stewardship for the iron and steel material cycles will be outcomes of the work reported here. The metrics used include materials flow analysis (MFA) and life cycle assessment (LCA). The mining and metals sector provides materials that are essential elements in a wide range of goods and services. By virtue of their inherent qualities (including strength, chemical resistance and lustre), minerals and metals create value by meeting human needs. The mining, refining and recycling industries, which make metals available for use in human societies around the globe, are under increasing pressure to improve their environmental performance and contribute more towards sustainable development. The steel industry is a major industry which consumes huge quantities of energy. It is therefore liable to cause environmental degradation, mainly due to greenhouse gas emissions. Iron and steel are the world’s most widely used material, produced in every region of the world. Today, steels are essential components of our society to the extent that they are part of every utility we use in our day-to-day life. Sustainable use of metals in general, and iron and steel in particular, requires the reduction of environmental impacts associated with the mining, refining and recycling activities that supply metals to economies around the world. By using MFA a quantitative model of current and projected iron ore and steel mass flows and to quantify the CO2 emissions resulting from iron ore and steel production was developed. This model is based on historical data extracted from various government organisations, industry associations and the annual reports of individual companies. Using LCA, the thesis has evaluated the benefits of recycling of steel to our society from environmental and economical perspectives. The quantitative metrics used to demonstrate the benefits of recycling include resource consumption, energy use and life cycle environmental emissions. A brief review is also presented of methodologies of allocation in open-loop recycling, the integration of design-for-recycling (DfR) principles into steel product manufacturing, and policies on steel recycling. In the context of LCA, a review of current characterisation methods in respect of abiotic resource depletion has been carried out. Using a case study of the steel industry, an argument is presented that abiotic resource depletion is a problem, both at a regional and global level from the ‘triple bottom line’ perspective. Finally, environmental stewardship issues and opportunities in the context of the minerals and metals sector are reviewed. Some industry examples and opportunities have been reported. A case study of the use of iron ore mineral wastes is presented to demonstrate how mineral industries can contribute positively to sustainable development by embracing the concepts of industrial ecology.