M. Bertram

Metal stocks and sustainability

The relative proportions of metal residing in ore in the lithosphere, in use in products providing services, and in waste deposits measure our progress from exclusive use of virgin ore toward full dependence on sustained use of recycled metal. In the U.S. at present, the copper contents of these three repositories are roughly equivalent, but metal in service continues to increase. Providing todays developed-country level of services for copper worldwide (as well as for zinc and, perhaps, platinum) would appear to require conversion of essentially all of the ore in the lithosphere to stock-in-use plus near-complete recycling of the metals from that point forward.

The contemporary European copper cycle: waste management subsystem

Abstract A comprehensive copper mass balance for waste management in Europe has been carried out, including municipal solid waste, construction and demolition waste, wastes from electrical and electronic equipment (WEEE), and end-of-life vehicles (ELV). The recycling efficiency of the current waste management system in Europe was quantified and the sources of copper scrap used for secondary copper production were determined. Additionally, an assessment of copper losses to the environment from incinerators and landfills was undertaken. As a final step, select parameters were varied to test the sensitivity of copper waste generation results to the uncertainties in the data. The total flows of copper into the European waste management system consists of 920 Gg/y domestic copper waste and of 300 Gg/y imported old scrap, of which 740 Gg/y are recycled and 480 Gg/y are landfilled. In Europe 2 kg per capita of copper waste is generated annually. WEEE and ELV are the most important domestic waste streams from the perspective of copper contents. They contain 67% of the total copper throughput, but only make up 4% of the mass of total waste generation. Because WEEE is the fastest growing waste category, this finding emphasizes the need for efficient WEEE recycling strategies. The overall recycling efficiency for Europe for copper in all types of waste, excluding prompt scrap and scrap imports, is 48%, with a range of 5–58% depending on the country. This shows further potential for increased recycling activities in the future. Emissions of copper to the environment are under 5 Gg/y but several new sources for emissions are not yet quantified. Uncertainties in waste generation rate and composition for some waste categories (WEEE, C&D) are high, and additional analysis is needed to confirm the above findings.

The contemporary European copper cycle: 1 year stocks and flows

Abstract Substance flow cycles can provide a picture of resource uses and losses through a geographic region, allowing us to evaluate regional resource management and estimate gross environmental impacts. This paper traces the flow of copper as it enters and leaves the European economy over 1 year and provides the numerical accounting of copper flows that are further analyzed in a companion paper in this issue. We examine the major flows of copper from ore, as it is extracted from the earth, transformed into products, and discarded or recycled. A regional material flow model was developed to estimate patterns of copper use in the early 1990s in select European countries. Successive mass balance calculations were used to determine copper flows, including the amount of metal that enters use in society and is deposited in waste repositories. A database that records temporal and spatial boundary conditions and data quality was developed for continental substance flow analysis. The majority of copper is mined, smelted, and refined outside of Europe. Across the life cycle, a net total of 1900 Gg/year of copper is imported into Europe. About 40% of cathode copper produced within the system is made from old and new scrap. It is estimated that approximately 8 kg of copper per person enters use in society, largely in infrastructure, buildings, industry, and private households. The majority of copper in finished products is contained in pure form (70%), the remainder in alloy form. The waste management system in Europe recycles about 60% of the copper from waste. The copper discard flow from post-consumer waste is roughly five times higher than that from copper production waste. This ratio would decrease if we consider production wastes generated outside of the European system boundary. The net addition of copper to the stock in society in the system is about 6 kg/person. Given the in-service lifetime of the applications of copper identified in this model, most of the copper processed during the last few decades still resides in society, mostly in non-dissipative uses.

The Multilevel Cycle of Anthropogenic Zinc

Summary A comprehensive annual cycle for stocks and flows of zinc, based on data from circa 1994 and incorporating information on extraction, processing, fabrication, use, discard, recycling, and landfilling, was carried out at three discrete governmental unit levels—54 countries and 1 country group (which together comprise essentially all global anthropogenic zinc stocks and flows), nine world regions, and the planet as a whole. All of these cycles are available in an electronic supplement to this article, which thus provides a metadata set on zinc flows for the use of industrial ecology researchers. A “best estimate” global zinc cycle was constructed to resolve aggregation discrepancies. Among the most interesting results are the following: (1) The accumulation ratio, that is, addition to in-use stock as a function of zinc entering use, is positive and large (2/3 of zinc entering use is added to stock) (country, regional, and global levels); (2) secondary input ratios (fractions of input to fabrication that are from recycled zinc) and domestic recycling percentages (fractions of discarded zinc that are recycled) differ among regions by as much as a factor of six (regional level); (3) worldwide, about 40% of the zinc that was discarded in various forms was recovered and reused or recycled (global level); (4) zinc cycles can usefully be characterized by a set of ratios, including, notably, the utilization efficiency (the ratio of manufacturing waste to manufacturing output: 0.090) and the prompt scrap ratio (new scrap as a fraction of manufacturing input: 0.070) (global level). Because capturable discards are a significant fraction of primary zinc inputs, if a larger proportion of discards were recaptured, extraction requirements would decrease significantly (global level). The results provide a framework for complementary studies in resource stocks, industrial resource utilization, energy consumption, waste management, industrial economics, and environmental impacts.

The contemporary European copper cycle: The characterization of technological copper cycles

Abstract Copper is an example of an anthropogenically utilized material that is of interest to both resource economists and environmental scientists. It is a widely employed industrial metal, and one that in certain forms and concentrations is moderately biotoxic. It is also one that may be potentially supply-limited. A comprehensive accounting of the anthropogenic mobilization and use of copper must treat a series of life stages: mining and processing, fabrication, utilization, and end of life. Reservoirs in which copper resides include the lithosphere, ore and ingot processing facilities, fabricators, at least a dozen major uses, several intentional and default stockpiles, landfills, and the environment. The flow rates among those reservoirs constitute the cycle. If a non-global cycle is being constructed, imports to and exports from the region of interest must also be included. In this paper we discuss the characteristics of each of the components of anthropogenic copper cycles, as well as generic approaches to the acquisition and evaluation of data over space and time. Data quality and data utility are evaluated, noting that information relevant to technology and resource policy is easier to acquire than is information relevant to human health and ecosystem concerns, partly because the spatial scale required by the latter is considerably smaller and the flow rates rarely analyzed and reported. Despite considerable data limitations, we conclude that information is sufficiently available and the data sufficiently accurate to characterize copper cycles at a variety of spatial scales.

The characterization of technological zinc cycles

A comprehensive accounting of the anthropogenic mobilization of zinc must treat a series of life stages: mining and processing, fabrication, utilization, and end of life. Reservoirs in which zinc resides include the lithosphere, ore and ingot processing facilities, at least a dozen major uses, several intentional and default stockpiles, landfills, and the environment. The flow rates among those reservoirs constitute the technological cycle. If a non-global cycle is being constructed, imports to and exports from the region of interest must also be included. In this paper we discuss generic approaches to the acquisition and evaluation of data for each of the components of anthropogenic zinc cycles over space and time. Data quality and data utility are evaluated, noting that information relevant to technology and resource policy is easier to acquire than is information relevant to human health and ecosystem concerns, partly because the spatial scale required by the latter is considerably smaller and the flow rates rarely analyzed and reported. Despite considerable data limitations, we conclude that information is sufficiently available and accurate to permit reasonably quantitative zinc cycles to be characterized at a variety of spatial scales.

The contemporary European zinc cycle : 1-year stocks and flows

Abstract A regional material stock and flow (STAF) model was constructed to track the pathway of zinc in the early 1990s in selected western European countries. This paper traces the major flows of zinc from ore, to product, to potential secondary resource as it moves through the European economy over 1 year. Successive mass balance estimations were used to determine zinc flows, including the amount of metal that enters stocks in waste reservoirs and products. A resource-specific model and database were used to allocate zinc flows and record temporal and spatial boundary data and data quality criteria. The model shows that for primary zinc, as for other non-ferrous metals, most is imported as concentrate from North and South America and Oceania, and is smelted in Europe to refined metal. It is estimated that 5 kg zinc per person enters use annually in the European economy; this is partly balanced by a flow to waste management of about 2 kg per capita. The largest flows of zinc in discard streams are in construction and demolition debris and in end-of-life vehicles. Only about 34% of the discarded zinc is recycled. While zincs residence time can be high for many of its applications in the building and construction sector, since the majority of zinc is used as an anti-corrosion coating, there are dissipative losses occurring during the lifetime of products and infrastructure containing zinc. This study and others suggest that zinc losses to the environment are significant in magnitude, and their impacts should be evaluated over time and at various spatial scales.

Where has all the copper gone: The stocks and flows project, part 1

The quantitative assessment of stocks and flows of materials throughout the technological cycle, from resource extraction to final disposal, can inform resource policy, environmental science, and waste management. This paper describes the technological cycle of copper based on work by the Stocks and Flows Project of the Yale Center for Industrial Ecology. Of copper produced in the 20th century, as much as 85% remains in use today. The recycling rate, while high, leaves nearly as much in waste destined for disposal (e.g., over 40% in the United States). The copper in production wastes currently approaches the quantity in post-consumer wastes, but the latter will dwarf the former over time as large in-use stocks reach end of life.

Exploratory Data Analysis of the Multilevel Anthropogenic Zinc Cycle

A comprehensive multilevel contemporary cycle for stocks and flows of zinc is analyzed by the tools of exploratory data analysis. The analysis is performed at three discrete organizational levels—country (53 countries and 1 country group that together comprise essentially all anthropogenic stocks and flows of zinc), world region (9 world regions), and the planet as a whole. The results demonstrate the following: (1) Exploratory data analysis provides valuable and otherwise unobtainable information about material flows, especially those across multiple spatial levels. (2) All distributions of countrylevel zinc stock and flow data are highly skewed, a few countries having large magnitudes, many having small magnitudes. Rates of fabrication of zinc‐containing products for the countries are poorly correlated with rates of extraction, reflecting the fact that many countries that extract zinc do not fabricate products from zinc to any significant degree, and vice versa. (4) Virtually all countries are adding zinc to stock in the use phase (in galvanizing applications, zinc castings, etc.). These rates of addition are highly correlated with rates of zinc entering use in all regions, and are higher in regions under vigorous development. (5) With weak confidence, the rate of zinc landfilling by countries appears to be highly correlated with the rate of discard. (6) The statistical distributions of regional‐level zinc cycle parameters are approximately log normal. (7) The extremes of normalized statistical distributions of zinc flow values are broader at lower spatial levels (country versus region, for example), but regional interquartile ranges for zinc entering use and zinc discards are higher at regional level then at country level.

Multilevel Anthropogenic Cycles of Copper and Zinc: A Comparative Statistical Analysis

Contemporary cycles for copper and zinc are coanalyzed with the tools of exploratory data analysis. One-year analyses (circa 1994) are performed at three discrete spatial levels-country (52 countries that comprise essentially all anthropogenic stocks and flows of the two metals), eight world regions, and the planet as a whole-and are completed both in absolute magnitude and in per capita terms. This work constitutes, to our knowledge, the first multiscale, multilevel analysis of anthropogenic resources throughout their life cycles. The results demonstrate that (1) A high degree of correlation exists between country-level copper and country-level zinc rates of fabrication and manufacturing, entry into use, net addition to in-use stocks, discard, and landfilling; (2) Regional-level rates for copper and zinc cycle parameters show the same correlations as exist at country level; (3) On a per capita basis, countries add to in-use stock almost 50% more copper than zinc; (4) The predominant discard streams for copper and zinc at the global level are different for the two metals, and relative rates of different loss processes differ geographically, so that resource recovery policies must be designed from metalspecific and location-specific perspectives; (5)When absolute magnitudes of life-cycle flows are considered, the standard deviations of the data sets decrease from country level to regional level for both copper and zinc, which is not the case for the per capita data sets, where the statistical properties of the data sets for both metals approach being independent of spatial level, thus providing a basis for predicting unmeasured per capita metal flow behavior.