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Dick van Beers, Marlen Bertram, Kensuke Fuse, Sabrina Spatari, and Thomas
Graedel
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Material
Flow Accounting (MFA) provides a framework to address resource
management and estimate gross environmental impacts, both spatially
and temporally. In this paper, the major flows over the entire
life-cycle of zinc are examined for the African continent for the
mid-1990s; these include production, fabrication and manufacturing
of semi- and finished products, use, and the waste management
system. According to the zinc flow model developed in this paper,
approximately 236 Gg zinc (236 000 metric tons) was mined annually
in Africa. The total flow of zinc in finished products entering use
exceeds the zinc flow in discarded products by large amounts. This
difference, approximately 0.17 kg Zn/(capita.yr) on average, is
added to the in-use reservoir, largely for galvanising applications
in domestic construction. Up to 55% of all discarded zinc (excluding
mining waste) is recycled. Much
of the remaining discarded zinc is diluted into other waste streams,
where recovery and recycling are probably not economically feasible.
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