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Sustainable metal resource management—the need for industrial development: efficiency improvement demands on metal resource management to enable a (sustainable) supply until 2050
J. Clenner Prod. Vol. 4, No. 2, pp. 97-104, 1996 Copyright 0 1996 Elsevier Science Ltd Printed in Greal Britain. All rights reserved 0959X526/96
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Sustainable metal resource management-the need for industrial development: efficiency improvement demands on metal resource management to enable a (sustainable) supply until 2050* Jens Brtibech Legatih Department of Manufacturing Engineering, Building 423, DK-2800 Lyngby, Denmark
The Technical
University
of Denmark,
This article will investigate just how much the manufacturing industry will have to improve the efficiency in use of non-renewable metal resources in a sustainable way from now until the year 2050, if industry is to provide material wealth to an ever growing world population with an ever growing demand for wealth. Given this development, the future demand for reduction in the use of the metals aluminum, tin, copper, silver and zinc by industry is projected forward to the year 2050. Scenarios determining pool dynamics include three scenarios for primary production: a projection of the present trend (exponential growth), a 2% extraction scenario and a no extraction scenario. The calculations show that the best long-term strategy for industry is a limitation to extraction, as, for example, suggested by the 2% extraction scenario. Further, the role of recycling in preserving the pool of a resource in use is emphasized. By varying the recycling rate, pool sizes for aluminum, tin, copper, silver and zinc are also projected forward to the year 2050. Recycling scenarios in this context are the present trend projection (exponential growth), full recycling and no recycling. The calculations clearly show that without an intensified focus on recycling, we cannot hope to fulfil even the most modest ambitions for sustainability in the use of metal resources. The paper goes on to investigate feasible courses of action, including trends in product design, like miniaturization, extended product life, substitution and design for recycling. It is argued that the best product-related strategy for industry is miniaturization. The paper does not deal solely with the issue of resource depletion, but rather with the industrial improvements in resource use needed to enable a continued (sustainable) supply of metals until the year 2050. The results of this study cannot be directly compared to other studies limiting themselves to the issue of resource depletion, as this study specifically deals with the extent of demands on industry for improvements in metal resource use. Copyright 0 1996 Elsevier Science Ltd Keywords: sustainable
development;
wealth
Introduction From The Limits to Growth3 in 1972 to the UNCED conference in Rio in 1992, the international community saw a development in concern from the initial realization that there are indeed limits to demographic and economic growth, to a worldwide appreciation and
*This article is based on two papers’.’ presented at the CONCEFI’ conference in Edinburgh, October 1995 and the ASME Annual Winter Meeting in San Francisco, November 1995
creation;
recycling; metal resources
agreement that the problem can only be solved in a global partnership. When it comes to the role of the manufacturing industry in ensuring a sustainable development, the message is this: It has to greatly reduce the use of raw materials and the product-related impact on the external environment, while preserving or improving the functionality of the products. This is the true contemporary challenge to the manufacturing industry-to supply the world community with material wealth using less raw materials and with less impact on the environmenti.
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4, Number
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Sustainable metal resource management:
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Through innovations in product development we have to achieve a sustainable use of natural resources and to bring down the impact on the external environment to a level that the earth’s ecosystems can cope with. This paper will investigate just how much the manufacturing industry will have to reduce the use of non-renewable metal resources in a sustainable way from now until the year 2050, if we are to provide material wealth to an ever growing world population with an ever growing demand for wealth. Given this development, the future demand for reductions in the use of the metals aluminum, tin, copper, silver and zinc by industry is projected forward to the year 2050. The treatment is centred around five combinations of primary production scenarios and secondary production scenarios, as shown in Figure 1. Each of these combinations is further combined with three economic growth scenarios. To see the effect of changing primary production, the primary production scenarios ‘present trend’ (fixed and projected exponential growth), ‘2% extraction’ (harvest at the most 2% of reserves each year) and ‘no extraction’ are combined with the present trend (also fixed exponential growth) in secondary production. Further, each of these three combinations are combined with three scenarios for economic growth, a present trend projection, a minimum growth for sustainability scenario and an equity scenario. The results of required industrial efficiency improvements for these combinations are shown in Table 2. To see the effect of changing recycling rates with a limitation in primary production, the 2% extraction primary production scenario is combined with three recycling scenarios: no recycling, present trend in recycling (fixed exponential growth) and full recycling. Each of these three combinations are combined with the three economic growth scenarios. The results of these combinations are shown in Table 3. Please note that the combination of the 2% extraction scenario with the present trend recycling scenario appears twice, and that there are, thus, five overall combinations of primary and secondary production scenarios, as shown in Figure 1. The paper goes on to investigate feasible courses of action, including strategies for product design, and the
required technological industry is discussed.
development
in the recovery
Selecting metals for study The virgin raw material reserves for primary production of metal are limited, and today we consume them at rates which will deplete some of our reserves within the foreseeable future. In order to satisfy the world communities’ need for increased material wealth, per capita consumption rates of most mineral resources are rising by l-3% every year. In 1984, a thorough study of the dynamics of resource depletion was presented by Goeller and Zucke?. They calculated the percentage depletion of a wide number of elements in the year 2100 under assumptions of growth in world population and the increasing demand for wealth. Using a mid- 1980s projection of world population and per capita consumption growth rates from the US Bureau of Mines along with the assumption that per capita consumption rates in developed countries will level off after the year 2000, and that per capita consumption in less developed countries will reach 50% of the 1982 level in the developed countries in the year 2100, they compared the cumulative demand in the period from 1982 to 2100 with the resource estimates in 1982. The resulting depletion percentages for some of the elements treated by Goeller and Zucker are shown in Table 1. It is evident that most metal resources are exhausted long before the year 2100 given the contemporary trend in consumption. In the following treatment, the pool dynamics of the metals aluminum, tin, copper, silver and zinc are investigated, representing a range from a not-so-scarce metal, over relatively scarce metals and to an extremely scarce metal. Three of these metals, aluminum, copper and zinc, are of importance to the manufacturing industry as a whole. However a great part of the manufacturing industry is the electronics industry, and it is the electronics industry that possesses the greatest improvement potentials and which may experience the largest demands on their ability to create wealth from metal resources. Therefore two additional metals are included in the study that are particularly critical for the electronics industry and further representative of the more exotic base metals and noble metals, namely tin and silver. For an in-depth discussion of the intensity of these resources in electronics products the reader is referred to other publications by the author’*6.
Present trend
2 % extraction
3 economic scenarios
3 economic scenarios
3 economic scenarios
No extraction Figure 1 Overview of scenario combinations
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Table 1 Depletion percentages in the year 2100 of some elements important to industry’ Element
Depletion (%)
Element
Depletion (%)
Zinc Silver Copper
581 439 206
Tin Aluminum
159 122
Sustainable metal resource management:
Parameters and scenarios
A model of creation of wealth from metal resources
Demographic
One of the important roles of industry in society is to create material wealth from natural resources through value added in manufacturing. The wealth of a country is traditionally measured as that country’s per capita gross national product (GNP), and summing up over nations and people, the global wealth may be expressed as a global GNP. The use of non-renewable metal resources plays together with numerous other factors in creating the wealth measured as the global GNP, and a simple way of visualizing the industry’s ability to create wealth from resources is given by the number of global GNP dollars that the use of a unit of some resource helps create. For example, an estimated pool of 171 million tons of copper in use in products in 1995 helps to create a global GNP of approximately 30,000 billion dollars.* This basic relationship is shown in Equation (1). Global GNP x (Resource in use/GNP dollar) = Pool of resource in use
(1)
Under assumptions of population growth and economic growth in the rich north and the poor south and using projection scenarios for pool feeding through primary production and pool conservation through recycling, it is possible to calculate the demands on industry in creating wealth from resources, expressed as the maximum amount of some resource that may be used in creating a GNP dollar. Such projection calculations from 1995 to 2050 for the use of the metals aluminum, tin, copper, silver and zinc are presented in the following discussion. By the term ‘pool’ used extensively in this paper is meant the amount of the metal in actual use in products at any given time. The pool may grow or decrease with time. The change of size of the pool is referred to as pool dynamics. The pool size is modelled as shown in Equation (2). Pool size (t) = Pool size (1995) + i
[PP(i) + SP(i) - DL(i)]
J.B. Legarth
growth scenario
When speaking of demographic and economic trends, the world is traditionally divided into the rich countries in the north and the poor countries in the south. The north is the major area of Europe and Northern America, Oceania and the former Soviet Union, whereas the south is the major area of Africa, Latin America and Asia. Concerning the projection of world population from now until 2050, the latest UN medium forecast is used’, predicting a world population of 10,019 million people in 2050-1233 million in the north and 8786 million in the south. The medium projection lies roughly in between the high projection (12,506 million people in 2050) and the low projection (7,813 million), and the medium projection is the one most often used, and the one most people believe in. The growth in world population takes place in the poor developing countries in the south, whereas the population forecast for the north predicts almost nil growth. Economic
growth scenarios
Concerning the economic developments in the north and south in the period, it is chosen to operate with three scenarios. Scenario one allows for a projected unlimited growth in GNP in the north of approximately 2.4% p.a. and a projected unlimited growth in the south of approximately 2.2% p.a. This is a present day scenario, which will inevitably widen the welfare gap between north and south. Scenario two still allows for unlimited growth in the north with today’s growth rate, but requires that the south reaches a 1995 north GNP per capita level in 2050. This means an average growth rate of approximately 4.7% p.a. in the south, which is the level generally perceived as a minimum if we shall achieve a sustainable development in the south*. The third scenario allows the GNP per capita in both north and south to grow to a level of $40,000 in 2050. This scenario is based on the equity principle, and aims for a level of wealth which is generally believed to ensure a good and healthy life for all*. Growth rates in scenario three are 1.7% in the north and 6.3% in the
(2)
k1995
1995 and 2050, where t = any year between PP = primary production, SP = secondary production and DL = dissipative losses.
Reserves -
Recycling
SecOlldary prodllction
A
V 1
* One source” states that between 1800 and 1986 a total of approximately 275 million tons of primary copper has been produced. Assuming no production prior to 1800 and using recent statistical data on primary copper production, a total of approximately 348 million tons of copper has been produced up to and including 1995. Under the assumption that recycling was fairly efficient until 1950 and that the average recycling rate in the rest of this century was 43%, a total loss of about 177 million tons of copper may be assessed, leaving a pool of copper in use in 1995 of I71 million tons.
pr+W
Pool
Dissitmtion
production Loss
Figure 2
Flow chart of exchanges
with the industrial pool of
material
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Sustainable metal resource management: J. 6. Legarth south. The World Bank definition is used as a measure of per capita GNP in the south, and all GNP estimates are in 1990 fixed prices. General scenarios for pool dynamics The pool of a resource in use at some point in time receives inputs from primary production (from ore) and secondary production (recycling), and loses material due to dissipative losses. In this study there are three scenarios in the simulation of primary production: a present day projection, a simple criterion allowing extraction at a maximum of 2% a year of the reserves as estimated that year, and a no extraction scenario calling for a complete stop of primary production. The present day scenario projects the trend in primary production seen in the last 15-20 years in a simple exponential growth model with a fixed annual percentage growth in production. Primary production growth rates were estimated to be 3.502% for aluminum, -1.300% for tin, 1.373% for copper, 2.477% for silver and 1.295% for zinc’. (Note that tin primary production is decreasing today.) Clearly, this scenario leads to complete depletion of reserves, for aluminum in 2074, for tin in 2044, for copper in 2036, for silver in 2012 and for zinc in 2009. The reserve estimates used for this study are those resources considered to be economic in 1995, excluding speculative and subeconomic resources, which may become available through technological and economical developments. The present trend scenario assumes a fixed growth rate until complete depletion. Scenario two is a simple limited extraction scenario based on the criterion that we shall preserve reserves for 50 years of primary production at any given time in the future8. The 50 year criterion or 2% extraction
- -
scenario is somewhat arbitrary. In scenario two the primary production of aluminum is limited from 2045, where the primary production level has reached 542% of the 1994 level. Tin primary production is immediately reduced to 72% in 1995 compared to the 1994 level, and drops to 24% of the 1994 level in 2050. The primary production of copper is limited from 1998 and drops eventually to 38% of the 1994 level in 2050. Silver primary production drops in 1995 to 40% of the 1994 level, to eventually end at 13% of the 1994 level in 2050. Zinc primary production is immediately reduced to 3 1% in 1995 compared to the 1994 level and drops to 10% of the 1994 level in 2050. The third scenario is the ultimate extreme of immediately ceasing to produce virgin raw materials because of the environmental effects involved. This is a no extraction scenario. Obviously, there is no further draw on natural resources, and preservation of the pool depends entirely on recycling. Concerning recycling, there are three secondary production scenarios in this study: a present day projection, a full recycling scenario and a no recycling scenario.
In the present day projection scenario, the trend of the last 15-20 years in recovery of metal from end-oflife products is extended. A simple exponential growth function with an average annual percentage growth is used, along the same lines as for primary production scenario one. Annual growth rates are 4.482% for aluminum, -1.192% for tin, 2.145% for copper, 2.642% for silver and 1.823% for zinc9. By estimating the average lifetime of the products in which the metals are used, it is possible to assess current recycling rates. The average lifetime for aluminum is estimated from use patterns and product lifetimes to 12 years, for tin 6 years, for copper 15 years, for silver 12 years and
Seal north and 9x2 north -
Scalsouth
’1’’’’ ScaZsouth 14 1 11 Sca3north - 8S!&sout,,
1990
Figure3
100
Economic growth scenarios
J. Cleaner Prod., 1996, Volume 4, Number 2
2020 Yaar
Sustainable metal resource management: J.B. Legarth Table2 The factor with which efficiency in wealth creation should improve in the year 2050 compared to 1995. Recycling follows the trend seen the last 15-20 years Primary production
Economic growth scenario Aluminum Tin Copper Silver Zinc
Table3
Present trend Present trend
Sustain. mini.
0.40 6.4 ;::
0.11 12.4 5.6 18.2 m
m
2% extraction
Equity 2:::: 10.2 33.3 cc
No extraction
Present trend
Sustain. mini.
Equity
Present trend
Sustain. mini.
Equity
0.42 5.3 2.3 6.8 13.9
0.82 10.3 4.5 13.1 27.1
1.5 18.9 8.2 24. I 49.7
14.9 6.3 10.1 7.9 00
29. I 12.2 19.6 15.3 m
53.3 22.3 36.0 28.0 00
Improvement factors in 2050 for the three recycling scenarios. Primary production is limited by the 2% extraction scenario
Secondary production
No recycling
Present trend recycling*
Full recycling
Economic growth scenario
Present trend
Sustain. mini.
Equity
Present trend
Sustain. mini.
Equity
Present trend
Sustain. mini.
Equity
Aluminum Tin Copper Silver Zinc
0.73 5.6 21.4 7.1 cc
I.4 10.9 41.7 13.9 cc
2.6 20.0 76.4 25.4 m
0.42 5.3 2.3 6.8 13.9
0.82 10.3 4.5 13.1 27.1
I.5 18.9 8.2 24. I 49.7
0.30 3.1 1.4 4.4 5.2
0.59 6.0 2.7 8.6 IO.1
I.1 II.0 5.0 15.7 18.5
*This column is the same as the second column in Table 2.
for zinc 10 years. Currently, recycling rates estimated from the projection calculations are for aluminum 46%, for tin 16%, for copper 49%, for silver 21%, and for zinc 19%. In scenario two, the full recycling scenario, the recycling rate is set to the maximum achievable recycling rate from 1995 onwards. Full recycling does not mean 100% recycling, because metals and other materials are indeed used for purposes that make recovery practically impossible-in chemical solutions, coatings, complex alloys, paints, etc. Full recycling of aluminum would be approximately 90% effective, for tin 80% effective, for copper 95% effective, for silver 70% effective and for zinc 80% effective. So the pool of a resource is depleted through dissipative losses, even with so-called full recycling.* The third recycling scenario is the extreme of no recycling from 1995 onwards. This scenario was chosen in order to truly show the importance of recycling in any strategy for sustainable use of non-renewable metal resources. Without recycling, the pool is automatically drained of the material put into the pool an average lifetime earlier. Five combinations are constructed from these three times three scenarios and each of these five combinations is evaluated for the three economic scenarios. All primary production scenarios are combined with the present trend recycling scenario, and the 50 year primary production scenario is combined with all the recycling scenarios. In this way the effects of extraction * The so-called full recycling rates are estimated on the basis of use patterns and average product lifetimes
limitations set against the present day trend may be seen, and the role of recycling in a limited extraction strategy may be investigated.
The results Table 2 states the results of the projection calculations of the combinations of the three primary production scenarios with the present trend recycling scenario and the three economic growth scenarios. The results are presented as the factors with which industry will have to have improved in wealth creation from a unit resource in the year 2050 compared to the ability for wealth creation in the year 1995. These factors are called improvement factors. It is obvious that the no extraction scenario puts very severe demands on industry indeed, much more severe demands than industry can be expected to fulfil. The no extraction scenario is not really a sensible option. This goes for all of the metals studied. Aluminum is sufficiently abundant for needs for industrial development, in the case of continuing with the present trend in economic growth or aiming for the sustainable minimum economic growth, to actually ease in 2050, even if the present trends in rise of primary production rates and recycling rates will prevail. In other words we have sufficient aluminum to go on as we do, and possibly even to fulfil the requirements of the equity scenario for economic growth, given a good ‘natural’ improvement in wealth creation efficiency. A natural improvement factor of 2-3, driven by wishes to save costs, can be expected for most metals. The same general picture emerges if
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the 2% extraction scenario is applied to primary production. That the need for industrial improvement ease means in practice that there is room for using aluminum as a substitute for other metals. Aluminum is the only one of the metals studied with this quality. For tin, copper and silver it appears that introducing the 2% extraction limitation to primary production is in fact a good long-term strategy, as needs for industrial improvement in 2050 with the 2% extraction scenario applied to primary production are less severe than continuing with the present trend in rises in primary production rates. The price to pay for this is, of course, that in the short and medium term, demands will be more severe. The introduction of the 2% extraction scenario is also a good long-term strategy for aluminum, but the effect appears beyond the year 2050, and is therefore not evident from Table 2. Zinc is an example of an extremely scarce resource. With the present trend in rises in primary production rates, the pool is effectively drained long before the year 2050, leading to, in principle, infinite improvement factors. The same goes if the no extraction scenario prevails. Only by limiting resource draw with the 2% extraction scenario or any other criterion can we achieve a pool of zinc in products also in the year 2050. It clearly appears from Table 2 that introducing some sort of limitation to primary production of metal resources seems to be a good long-term strategy for most metals. This goes also for more abundant metals, such as aluminum, but the need to limit primary production of these metals is not eminent. The results presented in Table 2 are results of projections assuming that recycling rates will rise as they have done for the last 15-20 years. It is interesting to see what the effect is from increasing recycling rates above this projected development. Table 3 presents projected improvement factors for a variety of recycling rates, namely the case of full recycling set against the case of no recycling at all and the case of recycling rates rising as they have done the last 15-20 years. The primary production is limited by the 2% extraction scenario, the best long-term strategy for industry concerning primary production. It is clear from Table 3 that increasing recycling rates immediately to full recycling eases the needs for industrial improvements somewhat in 2050. This is true for all of the metals studied. Of course, the higher the ambition for global economic growth, the greater the need for industrial improvements. What we should ideally aim for at minimum is the combination of the 2% extraction scenario applied to primary production and the minimum economic growth to ensure sustainability also in the south. Apart from aluminum, which is at the moment an unproblematic resource to harvest, all other metals studied display a need for industrial improvements greater than what can be expected from a natural, cost-driven improvement, even with full recycling. The natural improvement factor for copper is, e.g., approximately 1.9 from 1995 to 2050. This natural improvement factor was arrived
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at by looking at the development over the last approximately 20 years, and projecting this development forward from 1995 to the year 2050, over a 55 year period. So the sustainable strategy for the continued use of these metals involves not only some sort of limitation to the draw on scarce resources and, of course, full recycling, but also improvements in product design that will substantially lower the resource intensity of products. The next section investigates feasible courses of action.
Courses of action What can be done to remedy the situation with nonrenewable metal resources running short. To have a closer look at the basic Equation (I) is instructive: Global GNP x
(Resource in use/GNP dollar)
Limit population growth
Miniaturization
Demand for wealth
Longer product lives
Wealth vs. welfare
Substitution
=
Pool of resource in use
(1)
Recycling
Courses of action may be roughly divided into political and technological issues. Obvious political issues are related to the growth in global GNP, such as the possibilities of limiting the population growth, and more importantly to raise the question whether the industrialized countries have a legitimate demand for wealth, and, of course, a re-definition of the whole concept of welfare to shift the focus away from material wealth. Instead of the global GNP, a better factor in the basic equation would be a welfare indicator, a hot issue in contemporary economic research. These issues are clearly the domain of politics, philosophy and social and economic sciences, and this paper shall refrain from an in-depth discussion. Technology, on the other hand, may influence both pool dynamics and the use of resources in wealth creation. There are three clear trends which will facilitate the necessary development in the manufacturing industry: miniaturization, longer product use-life and substitution. Miniaturization, the manufacture of smaller products with preserved functionality, a major trend in, e.g., the consumer electronics industry, is one path towards sustainable use of metal resources. One prominent example is the cellular phone, which less than two decades ago was a rather unwieldy thing you had to carry in a briefcase, but which now fits right into your pocket. Generally, we see improvement potentials in resource use of a -factor of two to three
Sustainable
in a few product generations of consumer electronics. Using less materials may also easily show up at the bottom line of your balance sheet. Note that miniaturization in this context does not necessarily mean that the product gets smaller in volume, but rather that the use of critical resources such as zinc is reduced. A car or a TV set will obviously still have a certain size. Having products with a longer use-life would also decrease the depletion rate of metal resources, because the material in the product will stay longer in the pool of resources. (This does not hold, however, if recycling closes in on 100% efficiency.) There is no general trend towards longer product life, on the contrary, and although this would be beneficial to the pool, bringing up recycling rates would be a more efficient longterm strategy, because new generations of products, containing the recycled material, are likely to have a lower resource intensity. On first sight there seems to be a strong reason to extend product lifetimes from a basic resource management point of view, but this is only a good strategy as long as recycling rates are not full. With full recycling rates, the pool is unaffected by longer lifetimes, and the benefits of putting new product generations on the market with a content of recycled material will prevail. Substitution of harmful or scarce materials has been in focus for some time. Large-scale substitution of copper with aluminum is seen, e.g., in the electronics industry, for cables, etc. When there is room for using one metal as a substitute for another, as is the case with aluminum, substitution is a good short-term strategy. In the long run, however, substitution is not a true sustainable strategy, since it merely shifts the high consumption rates from the use of scarce resources to what today are less scarce resources that will inevitably become scarce resources themselves. Substitution as a strategy cannot stand alone. Focusing on pool dynamics, the effect of recycling is clear from Table 3. However, to achieve full recycling requires innovations in both product design and the recycling industry. Turning first to product design, what has become known as design for disassembly/recycling (DfIYR) is a rapidly growing field of research in both industry and the university worldlO, particularly in Germany, where product take-back legislation is pending. (Other European countries are expected to introduce similar legislation soon.) DfD/R involves designing products that are easily taken apart at their end-of-life to optimize recycling, and it involves avoiding putting together materials that cannot be separated later. Concerning the recycling loop, four elements have to be in place to ensure an optimum recycling of the resources so much needed. Firstly, an effective and flexible logistics system is needed to collect and transport end-of-life products from the end-user to the recipients in the recycling industry. Secondly, disassembly facilities with state-of-the-art technology are needed to disassemble end-of-life products into fractions that may be treated by the existing recycling
metal resource management:
J. B. Legarth
industry in an environmentally friendly way. Thirdly, new developments in the recycling industry must see the light of day in terms of increased capacity and new technology to deal with the complex mixtures of materials we will still see for a while yet. Technological development in the recycling industry is a comerstone in making the recycling industry an equal partner for the manufacturing industry. Finally, the marketing of recycled material must be improved to develop larger markets for existing materials and to open new markets for new recycled materials.
Concluding remarks Current estimates of world population growth, bringing the world population above 10 billion people in 2050, and the economic growth in developing countries necessary to bring about a sustainable development in these countries, bringing the per capita GNP in 2050 at least up to the level of developed countries today, sets a new challenge to the manufacturing industry. The industry will have to greatly reduce its use of non-renewable resources and the product related impact on the external environment through technological development and innovations in product design. This paper has focused on the need for industrial improvements in order to reduce the use of nonrenewable metal resources if a sustainable global development is to be achieved. Investigating the pool dynamics of five metals, aluminum-a not-so-scarce metal, tin, copper and silver-scarce metals and zincan extremely scarce metal, the demand on industry is illustrated by projecting the pools forward to the year 2050 under the assumption of three primary production scenarios (present trend, a 2% extraction scenario and a no extraction scenario), three scenarios for growth in global GNP (present trend, sustainable minimum and an equity scenario), and three recycling scenarios (present trend, full recycling and no recycling). For aluminum, such projections are presented for the three primary production scenarios combined with the three economic growth scenarios, fixing recycling at the present trend. When primary production is allowed to grow at the present rate or the 2% extraction scenario is applied, calling for the maximum annual consumption of 2% of the reserves, the pool of aluminum in use does not put any demands on industrial efficiency improvement from now until 2050, if the two most lenient economic growth scenarios prevail, and puts only minor demands on industry if the equity economic growth scenario prevails. The no extraction primary production scenario, however, reduces the maximum allowable use of aluminum to below 10% of today’s level in 2050, Similar projections were made for tin, copper and silver. Here there is a need for immediate action, as, e.g., copper use should be reduced by a factor of 2 to 40 in 2050 depending on the scenario. The 2% extraction scenario for primary production ensures the least
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Sustainable metal resource management: J.B. Legarth need for industrial improvement in the long run. Similar conclusions go for the metals tin and silver. For zinc, the prospects are bleak. Unless a 2% extraction scenario or some other limitation to primary production is introduced soon, the pool of zinc in use in products will be practically fully drained by the year 2020, and with a 2% extraction scenario applied to primary production we still have to face a reduction by more than a factor of 10 within 20 years. In order to investigate the role of recycling in preserving the pool, aluminum, tin, copper, silver and zinc pool projections were made for full recycling, contemporary recycling and no recycling situations, using the 2% extraction scenario as a primary production scenario. It is clearly shown that recycling plays a key role in resource dynamics, and that any sustainable strategy for resource use should put emphasis on recycling as a means of pool preservation. To meet these new challenges to technology, innovations in product design towards miniaturization, longer product life and substitution of less scarce metals for scarce metals along with an intense focus on bringing the recycling rate up to a maximum will bring us part of the way. What we cannot achieve technologically has to be dealt with otherwise, and we may have to fully redefine our perception of
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welfare, if the world is to achieve a sustainable development.
References I
Legarth, J.B. and Alting, L. Demands on the electronics industry in sustainable use of metal resources, Proceedings of the International Conference on Clean Electronics Products and Technology-CONCEPT, Edinburgh, October 1995,
2
PP. 60-65 Legarth, J.B. and Alting, L. Demands on industry in sustainable use of metal resources, Proceedings of the 1995 ASME International Mechanical and Engineering Congress and Exposition, San Francisco, November, 1995 Meadows, D.H. et al,, The Limits to Growth, Universe Books,
7 8
9
10 11
New York, 1972 United Nations, Agenda 21-The United Nations Programme of Action from Rio, 1993 Goeller, H.E. and Zucker, A. Infinite resources: the ultimate strategy, Science, 1984, 223, 456 Legarth, J.B. Recycling of electronic scrap, Ph.D. dissertation AP 96.08, IPT.96.08-A from the Department of Manufacturing Engineering, The Technical University of Denmark, 1996 United Nations, Long Range World Population Projections 1950-2150, 1992 Weterings, R.A.P.M. and Opschoor, J.B. The eco-capacity. as a challenge to technological development, RMNO publication No. 74a, The Netherlands, 1992 Metallstatistik, published annually by the German Metallgesellshaft, various years Jovane, F. et al. A key issue in product life cycle: disassembly, Annals of the CIRP, 1993, 42(2), 651 Ullmann’s Encyclopedia of Industrial Chemistry 5th edn., 1986, vol A7, p. 472
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Sustainable metal resource management-the need for industrial development: efficiency improvement demands on metal resource management to enable a (sustainable) supply until 2050* Jens Brtibech Legatih Department of Manufacturing Engineering, Building 423, DK-2800 Lyngby, Denmark
The Technical
University
of Denmark,
This article will investigate just how much the manufacturing industry will have to improve the efficiency in use of non-renewable metal resources in a sustainable way from now until the year 2050, if industry is to provide material wealth to an ever growing world population with an ever growing demand for wealth. Given this development, the future demand for reduction in the use of the metals aluminum, tin, copper, silver and zinc by industry is projected forward to the year 2050. Scenarios determining pool dynamics include three scenarios for primary production: a projection of the present trend (exponential growth), a 2% extraction scenario and a no extraction scenario. The calculations show that the best long-term strategy for industry is a limitation to extraction, as, for example, suggested by the 2% extraction scenario. Further, the role of recycling in preserving the pool of a resource in use is emphasized. By varying the recycling rate, pool sizes for aluminum, tin, copper, silver and zinc are also projected forward to the year 2050. Recycling scenarios in this context are the present trend projection (exponential growth), full recycling and no recycling. The calculations clearly show that without an intensified focus on recycling, we cannot hope to fulfil even the most modest ambitions for sustainability in the use of metal resources. The paper goes on to investigate feasible courses of action, including trends in product design, like miniaturization, extended product life, substitution and design for recycling. It is argued that the best product-related strategy for industry is miniaturization. The paper does not deal solely with the issue of resource depletion, but rather with the industrial improvements in resource use needed to enable a continued (sustainable) supply of metals until the year 2050. The results of this study cannot be directly compared to other studies limiting themselves to the issue of resource depletion, as this study specifically deals with the extent of demands on industry for improvements in metal resource use. Copyright 0 1996 Elsevier Science Ltd Keywords: sustainable
development;
wealth
Introduction From The Limits to Growth3 in 1972 to the UNCED conference in Rio in 1992, the international community saw a development in concern from the initial realization that there are indeed limits to demographic and economic growth, to a worldwide appreciation and
*This article is based on two papers’.’ presented at the CONCEFI’ conference in Edinburgh, October 1995 and the ASME Annual Winter Meeting in San Francisco, November 1995
creation;
recycling; metal resources
agreement that the problem can only be solved in a global partnership. When it comes to the role of the manufacturing industry in ensuring a sustainable development, the message is this: It has to greatly reduce the use of raw materials and the product-related impact on the external environment, while preserving or improving the functionality of the products. This is the true contemporary challenge to the manufacturing industry-to supply the world community with material wealth using less raw materials and with less impact on the environmenti.
J. Cleaner
Prod.,
1996, Volume
4, Number
2
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Sustainable metal resource management:
J. B. Legarth
Through innovations in product development we have to achieve a sustainable use of natural resources and to bring down the impact on the external environment to a level that the earth’s ecosystems can cope with. This paper will investigate just how much the manufacturing industry will have to reduce the use of non-renewable metal resources in a sustainable way from now until the year 2050, if we are to provide material wealth to an ever growing world population with an ever growing demand for wealth. Given this development, the future demand for reductions in the use of the metals aluminum, tin, copper, silver and zinc by industry is projected forward to the year 2050. The treatment is centred around five combinations of primary production scenarios and secondary production scenarios, as shown in Figure 1. Each of these combinations is further combined with three economic growth scenarios. To see the effect of changing primary production, the primary production scenarios ‘present trend’ (fixed and projected exponential growth), ‘2% extraction’ (harvest at the most 2% of reserves each year) and ‘no extraction’ are combined with the present trend (also fixed exponential growth) in secondary production. Further, each of these three combinations are combined with three scenarios for economic growth, a present trend projection, a minimum growth for sustainability scenario and an equity scenario. The results of required industrial efficiency improvements for these combinations are shown in Table 2. To see the effect of changing recycling rates with a limitation in primary production, the 2% extraction primary production scenario is combined with three recycling scenarios: no recycling, present trend in recycling (fixed exponential growth) and full recycling. Each of these three combinations are combined with the three economic growth scenarios. The results of these combinations are shown in Table 3. Please note that the combination of the 2% extraction scenario with the present trend recycling scenario appears twice, and that there are, thus, five overall combinations of primary and secondary production scenarios, as shown in Figure 1. The paper goes on to investigate feasible courses of action, including strategies for product design, and the
required technological industry is discussed.
development
in the recovery
Selecting metals for study The virgin raw material reserves for primary production of metal are limited, and today we consume them at rates which will deplete some of our reserves within the foreseeable future. In order to satisfy the world communities’ need for increased material wealth, per capita consumption rates of most mineral resources are rising by l-3% every year. In 1984, a thorough study of the dynamics of resource depletion was presented by Goeller and Zucke?. They calculated the percentage depletion of a wide number of elements in the year 2100 under assumptions of growth in world population and the increasing demand for wealth. Using a mid- 1980s projection of world population and per capita consumption growth rates from the US Bureau of Mines along with the assumption that per capita consumption rates in developed countries will level off after the year 2000, and that per capita consumption in less developed countries will reach 50% of the 1982 level in the developed countries in the year 2100, they compared the cumulative demand in the period from 1982 to 2100 with the resource estimates in 1982. The resulting depletion percentages for some of the elements treated by Goeller and Zucker are shown in Table 1. It is evident that most metal resources are exhausted long before the year 2100 given the contemporary trend in consumption. In the following treatment, the pool dynamics of the metals aluminum, tin, copper, silver and zinc are investigated, representing a range from a not-so-scarce metal, over relatively scarce metals and to an extremely scarce metal. Three of these metals, aluminum, copper and zinc, are of importance to the manufacturing industry as a whole. However a great part of the manufacturing industry is the electronics industry, and it is the electronics industry that possesses the greatest improvement potentials and which may experience the largest demands on their ability to create wealth from metal resources. Therefore two additional metals are included in the study that are particularly critical for the electronics industry and further representative of the more exotic base metals and noble metals, namely tin and silver. For an in-depth discussion of the intensity of these resources in electronics products the reader is referred to other publications by the author’*6.
Present trend
2 % extraction
3 economic scenarios
3 economic scenarios
3 economic scenarios
No extraction Figure 1 Overview of scenario combinations
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J. Cleaner Prod., 1996, Volume 4, Number 2
Table 1 Depletion percentages in the year 2100 of some elements important to industry’ Element
Depletion (%)
Element
Depletion (%)
Zinc Silver Copper
581 439 206
Tin Aluminum
159 122
Sustainable metal resource management:
Parameters and scenarios
A model of creation of wealth from metal resources
Demographic
One of the important roles of industry in society is to create material wealth from natural resources through value added in manufacturing. The wealth of a country is traditionally measured as that country’s per capita gross national product (GNP), and summing up over nations and people, the global wealth may be expressed as a global GNP. The use of non-renewable metal resources plays together with numerous other factors in creating the wealth measured as the global GNP, and a simple way of visualizing the industry’s ability to create wealth from resources is given by the number of global GNP dollars that the use of a unit of some resource helps create. For example, an estimated pool of 171 million tons of copper in use in products in 1995 helps to create a global GNP of approximately 30,000 billion dollars.* This basic relationship is shown in Equation (1). Global GNP x (Resource in use/GNP dollar) = Pool of resource in use
(1)
Under assumptions of population growth and economic growth in the rich north and the poor south and using projection scenarios for pool feeding through primary production and pool conservation through recycling, it is possible to calculate the demands on industry in creating wealth from resources, expressed as the maximum amount of some resource that may be used in creating a GNP dollar. Such projection calculations from 1995 to 2050 for the use of the metals aluminum, tin, copper, silver and zinc are presented in the following discussion. By the term ‘pool’ used extensively in this paper is meant the amount of the metal in actual use in products at any given time. The pool may grow or decrease with time. The change of size of the pool is referred to as pool dynamics. The pool size is modelled as shown in Equation (2). Pool size (t) = Pool size (1995) + i
[PP(i) + SP(i) - DL(i)]
J.B. Legarth
growth scenario
When speaking of demographic and economic trends, the world is traditionally divided into the rich countries in the north and the poor countries in the south. The north is the major area of Europe and Northern America, Oceania and the former Soviet Union, whereas the south is the major area of Africa, Latin America and Asia. Concerning the projection of world population from now until 2050, the latest UN medium forecast is used’, predicting a world population of 10,019 million people in 2050-1233 million in the north and 8786 million in the south. The medium projection lies roughly in between the high projection (12,506 million people in 2050) and the low projection (7,813 million), and the medium projection is the one most often used, and the one most people believe in. The growth in world population takes place in the poor developing countries in the south, whereas the population forecast for the north predicts almost nil growth. Economic
growth scenarios
Concerning the economic developments in the north and south in the period, it is chosen to operate with three scenarios. Scenario one allows for a projected unlimited growth in GNP in the north of approximately 2.4% p.a. and a projected unlimited growth in the south of approximately 2.2% p.a. This is a present day scenario, which will inevitably widen the welfare gap between north and south. Scenario two still allows for unlimited growth in the north with today’s growth rate, but requires that the south reaches a 1995 north GNP per capita level in 2050. This means an average growth rate of approximately 4.7% p.a. in the south, which is the level generally perceived as a minimum if we shall achieve a sustainable development in the south*. The third scenario allows the GNP per capita in both north and south to grow to a level of $40,000 in 2050. This scenario is based on the equity principle, and aims for a level of wealth which is generally believed to ensure a good and healthy life for all*. Growth rates in scenario three are 1.7% in the north and 6.3% in the
(2)
k1995
1995 and 2050, where t = any year between PP = primary production, SP = secondary production and DL = dissipative losses.
Reserves -
Recycling
SecOlldary prodllction
A
V 1
* One source” states that between 1800 and 1986 a total of approximately 275 million tons of primary copper has been produced. Assuming no production prior to 1800 and using recent statistical data on primary copper production, a total of approximately 348 million tons of copper has been produced up to and including 1995. Under the assumption that recycling was fairly efficient until 1950 and that the average recycling rate in the rest of this century was 43%, a total loss of about 177 million tons of copper may be assessed, leaving a pool of copper in use in 1995 of I71 million tons.
pr+W
Pool
Dissitmtion
production Loss
Figure 2
Flow chart of exchanges
with the industrial pool of
material
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Sustainable metal resource management: J. 6. Legarth south. The World Bank definition is used as a measure of per capita GNP in the south, and all GNP estimates are in 1990 fixed prices. General scenarios for pool dynamics The pool of a resource in use at some point in time receives inputs from primary production (from ore) and secondary production (recycling), and loses material due to dissipative losses. In this study there are three scenarios in the simulation of primary production: a present day projection, a simple criterion allowing extraction at a maximum of 2% a year of the reserves as estimated that year, and a no extraction scenario calling for a complete stop of primary production. The present day scenario projects the trend in primary production seen in the last 15-20 years in a simple exponential growth model with a fixed annual percentage growth in production. Primary production growth rates were estimated to be 3.502% for aluminum, -1.300% for tin, 1.373% for copper, 2.477% for silver and 1.295% for zinc’. (Note that tin primary production is decreasing today.) Clearly, this scenario leads to complete depletion of reserves, for aluminum in 2074, for tin in 2044, for copper in 2036, for silver in 2012 and for zinc in 2009. The reserve estimates used for this study are those resources considered to be economic in 1995, excluding speculative and subeconomic resources, which may become available through technological and economical developments. The present trend scenario assumes a fixed growth rate until complete depletion. Scenario two is a simple limited extraction scenario based on the criterion that we shall preserve reserves for 50 years of primary production at any given time in the future8. The 50 year criterion or 2% extraction
- -
scenario is somewhat arbitrary. In scenario two the primary production of aluminum is limited from 2045, where the primary production level has reached 542% of the 1994 level. Tin primary production is immediately reduced to 72% in 1995 compared to the 1994 level, and drops to 24% of the 1994 level in 2050. The primary production of copper is limited from 1998 and drops eventually to 38% of the 1994 level in 2050. Silver primary production drops in 1995 to 40% of the 1994 level, to eventually end at 13% of the 1994 level in 2050. Zinc primary production is immediately reduced to 3 1% in 1995 compared to the 1994 level and drops to 10% of the 1994 level in 2050. The third scenario is the ultimate extreme of immediately ceasing to produce virgin raw materials because of the environmental effects involved. This is a no extraction scenario. Obviously, there is no further draw on natural resources, and preservation of the pool depends entirely on recycling. Concerning recycling, there are three secondary production scenarios in this study: a present day projection, a full recycling scenario and a no recycling scenario.
In the present day projection scenario, the trend of the last 15-20 years in recovery of metal from end-oflife products is extended. A simple exponential growth function with an average annual percentage growth is used, along the same lines as for primary production scenario one. Annual growth rates are 4.482% for aluminum, -1.192% for tin, 2.145% for copper, 2.642% for silver and 1.823% for zinc9. By estimating the average lifetime of the products in which the metals are used, it is possible to assess current recycling rates. The average lifetime for aluminum is estimated from use patterns and product lifetimes to 12 years, for tin 6 years, for copper 15 years, for silver 12 years and
Seal north and 9x2 north -
Scalsouth
’1’’’’ ScaZsouth 14 1 11 Sca3north - 8S!&sout,,
1990
Figure3
100
Economic growth scenarios
J. Cleaner Prod., 1996, Volume 4, Number 2
2020 Yaar
Sustainable metal resource management: J.B. Legarth Table2 The factor with which efficiency in wealth creation should improve in the year 2050 compared to 1995. Recycling follows the trend seen the last 15-20 years Primary production
Economic growth scenario Aluminum Tin Copper Silver Zinc
Table3
Present trend Present trend
Sustain. mini.
0.40 6.4 ;::
0.11 12.4 5.6 18.2 m
m
2% extraction
Equity 2:::: 10.2 33.3 cc
No extraction
Present trend
Sustain. mini.
Equity
Present trend
Sustain. mini.
Equity
0.42 5.3 2.3 6.8 13.9
0.82 10.3 4.5 13.1 27.1
1.5 18.9 8.2 24. I 49.7
14.9 6.3 10.1 7.9 00
29. I 12.2 19.6 15.3 m
53.3 22.3 36.0 28.0 00
Improvement factors in 2050 for the three recycling scenarios. Primary production is limited by the 2% extraction scenario
Secondary production
No recycling
Present trend recycling*
Full recycling
Economic growth scenario
Present trend
Sustain. mini.
Equity
Present trend
Sustain. mini.
Equity
Present trend
Sustain. mini.
Equity
Aluminum Tin Copper Silver Zinc
0.73 5.6 21.4 7.1 cc
I.4 10.9 41.7 13.9 cc
2.6 20.0 76.4 25.4 m
0.42 5.3 2.3 6.8 13.9
0.82 10.3 4.5 13.1 27.1
I.5 18.9 8.2 24. I 49.7
0.30 3.1 1.4 4.4 5.2
0.59 6.0 2.7 8.6 IO.1
I.1 II.0 5.0 15.7 18.5
*This column is the same as the second column in Table 2.
for zinc 10 years. Currently, recycling rates estimated from the projection calculations are for aluminum 46%, for tin 16%, for copper 49%, for silver 21%, and for zinc 19%. In scenario two, the full recycling scenario, the recycling rate is set to the maximum achievable recycling rate from 1995 onwards. Full recycling does not mean 100% recycling, because metals and other materials are indeed used for purposes that make recovery practically impossible-in chemical solutions, coatings, complex alloys, paints, etc. Full recycling of aluminum would be approximately 90% effective, for tin 80% effective, for copper 95% effective, for silver 70% effective and for zinc 80% effective. So the pool of a resource is depleted through dissipative losses, even with so-called full recycling.* The third recycling scenario is the extreme of no recycling from 1995 onwards. This scenario was chosen in order to truly show the importance of recycling in any strategy for sustainable use of non-renewable metal resources. Without recycling, the pool is automatically drained of the material put into the pool an average lifetime earlier. Five combinations are constructed from these three times three scenarios and each of these five combinations is evaluated for the three economic scenarios. All primary production scenarios are combined with the present trend recycling scenario, and the 50 year primary production scenario is combined with all the recycling scenarios. In this way the effects of extraction * The so-called full recycling rates are estimated on the basis of use patterns and average product lifetimes
limitations set against the present day trend may be seen, and the role of recycling in a limited extraction strategy may be investigated.
The results Table 2 states the results of the projection calculations of the combinations of the three primary production scenarios with the present trend recycling scenario and the three economic growth scenarios. The results are presented as the factors with which industry will have to have improved in wealth creation from a unit resource in the year 2050 compared to the ability for wealth creation in the year 1995. These factors are called improvement factors. It is obvious that the no extraction scenario puts very severe demands on industry indeed, much more severe demands than industry can be expected to fulfil. The no extraction scenario is not really a sensible option. This goes for all of the metals studied. Aluminum is sufficiently abundant for needs for industrial development, in the case of continuing with the present trend in economic growth or aiming for the sustainable minimum economic growth, to actually ease in 2050, even if the present trends in rise of primary production rates and recycling rates will prevail. In other words we have sufficient aluminum to go on as we do, and possibly even to fulfil the requirements of the equity scenario for economic growth, given a good ‘natural’ improvement in wealth creation efficiency. A natural improvement factor of 2-3, driven by wishes to save costs, can be expected for most metals. The same general picture emerges if
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the 2% extraction scenario is applied to primary production. That the need for industrial improvement ease means in practice that there is room for using aluminum as a substitute for other metals. Aluminum is the only one of the metals studied with this quality. For tin, copper and silver it appears that introducing the 2% extraction limitation to primary production is in fact a good long-term strategy, as needs for industrial improvement in 2050 with the 2% extraction scenario applied to primary production are less severe than continuing with the present trend in rises in primary production rates. The price to pay for this is, of course, that in the short and medium term, demands will be more severe. The introduction of the 2% extraction scenario is also a good long-term strategy for aluminum, but the effect appears beyond the year 2050, and is therefore not evident from Table 2. Zinc is an example of an extremely scarce resource. With the present trend in rises in primary production rates, the pool is effectively drained long before the year 2050, leading to, in principle, infinite improvement factors. The same goes if the no extraction scenario prevails. Only by limiting resource draw with the 2% extraction scenario or any other criterion can we achieve a pool of zinc in products also in the year 2050. It clearly appears from Table 2 that introducing some sort of limitation to primary production of metal resources seems to be a good long-term strategy for most metals. This goes also for more abundant metals, such as aluminum, but the need to limit primary production of these metals is not eminent. The results presented in Table 2 are results of projections assuming that recycling rates will rise as they have done for the last 15-20 years. It is interesting to see what the effect is from increasing recycling rates above this projected development. Table 3 presents projected improvement factors for a variety of recycling rates, namely the case of full recycling set against the case of no recycling at all and the case of recycling rates rising as they have done the last 15-20 years. The primary production is limited by the 2% extraction scenario, the best long-term strategy for industry concerning primary production. It is clear from Table 3 that increasing recycling rates immediately to full recycling eases the needs for industrial improvements somewhat in 2050. This is true for all of the metals studied. Of course, the higher the ambition for global economic growth, the greater the need for industrial improvements. What we should ideally aim for at minimum is the combination of the 2% extraction scenario applied to primary production and the minimum economic growth to ensure sustainability also in the south. Apart from aluminum, which is at the moment an unproblematic resource to harvest, all other metals studied display a need for industrial improvements greater than what can be expected from a natural, cost-driven improvement, even with full recycling. The natural improvement factor for copper is, e.g., approximately 1.9 from 1995 to 2050. This natural improvement factor was arrived
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at by looking at the development over the last approximately 20 years, and projecting this development forward from 1995 to the year 2050, over a 55 year period. So the sustainable strategy for the continued use of these metals involves not only some sort of limitation to the draw on scarce resources and, of course, full recycling, but also improvements in product design that will substantially lower the resource intensity of products. The next section investigates feasible courses of action.
Courses of action What can be done to remedy the situation with nonrenewable metal resources running short. To have a closer look at the basic Equation (I) is instructive: Global GNP x
(Resource in use/GNP dollar)
Limit population growth
Miniaturization
Demand for wealth
Longer product lives
Wealth vs. welfare
Substitution
=
Pool of resource in use
(1)
Recycling
Courses of action may be roughly divided into political and technological issues. Obvious political issues are related to the growth in global GNP, such as the possibilities of limiting the population growth, and more importantly to raise the question whether the industrialized countries have a legitimate demand for wealth, and, of course, a re-definition of the whole concept of welfare to shift the focus away from material wealth. Instead of the global GNP, a better factor in the basic equation would be a welfare indicator, a hot issue in contemporary economic research. These issues are clearly the domain of politics, philosophy and social and economic sciences, and this paper shall refrain from an in-depth discussion. Technology, on the other hand, may influence both pool dynamics and the use of resources in wealth creation. There are three clear trends which will facilitate the necessary development in the manufacturing industry: miniaturization, longer product use-life and substitution. Miniaturization, the manufacture of smaller products with preserved functionality, a major trend in, e.g., the consumer electronics industry, is one path towards sustainable use of metal resources. One prominent example is the cellular phone, which less than two decades ago was a rather unwieldy thing you had to carry in a briefcase, but which now fits right into your pocket. Generally, we see improvement potentials in resource use of a -factor of two to three
Sustainable
in a few product generations of consumer electronics. Using less materials may also easily show up at the bottom line of your balance sheet. Note that miniaturization in this context does not necessarily mean that the product gets smaller in volume, but rather that the use of critical resources such as zinc is reduced. A car or a TV set will obviously still have a certain size. Having products with a longer use-life would also decrease the depletion rate of metal resources, because the material in the product will stay longer in the pool of resources. (This does not hold, however, if recycling closes in on 100% efficiency.) There is no general trend towards longer product life, on the contrary, and although this would be beneficial to the pool, bringing up recycling rates would be a more efficient longterm strategy, because new generations of products, containing the recycled material, are likely to have a lower resource intensity. On first sight there seems to be a strong reason to extend product lifetimes from a basic resource management point of view, but this is only a good strategy as long as recycling rates are not full. With full recycling rates, the pool is unaffected by longer lifetimes, and the benefits of putting new product generations on the market with a content of recycled material will prevail. Substitution of harmful or scarce materials has been in focus for some time. Large-scale substitution of copper with aluminum is seen, e.g., in the electronics industry, for cables, etc. When there is room for using one metal as a substitute for another, as is the case with aluminum, substitution is a good short-term strategy. In the long run, however, substitution is not a true sustainable strategy, since it merely shifts the high consumption rates from the use of scarce resources to what today are less scarce resources that will inevitably become scarce resources themselves. Substitution as a strategy cannot stand alone. Focusing on pool dynamics, the effect of recycling is clear from Table 3. However, to achieve full recycling requires innovations in both product design and the recycling industry. Turning first to product design, what has become known as design for disassembly/recycling (DfIYR) is a rapidly growing field of research in both industry and the university worldlO, particularly in Germany, where product take-back legislation is pending. (Other European countries are expected to introduce similar legislation soon.) DfD/R involves designing products that are easily taken apart at their end-of-life to optimize recycling, and it involves avoiding putting together materials that cannot be separated later. Concerning the recycling loop, four elements have to be in place to ensure an optimum recycling of the resources so much needed. Firstly, an effective and flexible logistics system is needed to collect and transport end-of-life products from the end-user to the recipients in the recycling industry. Secondly, disassembly facilities with state-of-the-art technology are needed to disassemble end-of-life products into fractions that may be treated by the existing recycling
metal resource management:
J. B. Legarth
industry in an environmentally friendly way. Thirdly, new developments in the recycling industry must see the light of day in terms of increased capacity and new technology to deal with the complex mixtures of materials we will still see for a while yet. Technological development in the recycling industry is a comerstone in making the recycling industry an equal partner for the manufacturing industry. Finally, the marketing of recycled material must be improved to develop larger markets for existing materials and to open new markets for new recycled materials.
Concluding remarks Current estimates of world population growth, bringing the world population above 10 billion people in 2050, and the economic growth in developing countries necessary to bring about a sustainable development in these countries, bringing the per capita GNP in 2050 at least up to the level of developed countries today, sets a new challenge to the manufacturing industry. The industry will have to greatly reduce its use of non-renewable resources and the product related impact on the external environment through technological development and innovations in product design. This paper has focused on the need for industrial improvements in order to reduce the use of nonrenewable metal resources if a sustainable global development is to be achieved. Investigating the pool dynamics of five metals, aluminum-a not-so-scarce metal, tin, copper and silver-scarce metals and zincan extremely scarce metal, the demand on industry is illustrated by projecting the pools forward to the year 2050 under the assumption of three primary production scenarios (present trend, a 2% extraction scenario and a no extraction scenario), three scenarios for growth in global GNP (present trend, sustainable minimum and an equity scenario), and three recycling scenarios (present trend, full recycling and no recycling). For aluminum, such projections are presented for the three primary production scenarios combined with the three economic growth scenarios, fixing recycling at the present trend. When primary production is allowed to grow at the present rate or the 2% extraction scenario is applied, calling for the maximum annual consumption of 2% of the reserves, the pool of aluminum in use does not put any demands on industrial efficiency improvement from now until 2050, if the two most lenient economic growth scenarios prevail, and puts only minor demands on industry if the equity economic growth scenario prevails. The no extraction primary production scenario, however, reduces the maximum allowable use of aluminum to below 10% of today’s level in 2050, Similar projections were made for tin, copper and silver. Here there is a need for immediate action, as, e.g., copper use should be reduced by a factor of 2 to 40 in 2050 depending on the scenario. The 2% extraction scenario for primary production ensures the least
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Sustainable metal resource management: J.B. Legarth need for industrial improvement in the long run. Similar conclusions go for the metals tin and silver. For zinc, the prospects are bleak. Unless a 2% extraction scenario or some other limitation to primary production is introduced soon, the pool of zinc in use in products will be practically fully drained by the year 2020, and with a 2% extraction scenario applied to primary production we still have to face a reduction by more than a factor of 10 within 20 years. In order to investigate the role of recycling in preserving the pool, aluminum, tin, copper, silver and zinc pool projections were made for full recycling, contemporary recycling and no recycling situations, using the 2% extraction scenario as a primary production scenario. It is clearly shown that recycling plays a key role in resource dynamics, and that any sustainable strategy for resource use should put emphasis on recycling as a means of pool preservation. To meet these new challenges to technology, innovations in product design towards miniaturization, longer product life and substitution of less scarce metals for scarce metals along with an intense focus on bringing the recycling rate up to a maximum will bring us part of the way. What we cannot achieve technologically has to be dealt with otherwise, and we may have to fully redefine our perception of
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welfare, if the world is to achieve a sustainable development.
References I
Legarth, J.B. and Alting, L. Demands on the electronics industry in sustainable use of metal resources, Proceedings of the International Conference on Clean Electronics Products and Technology-CONCEPT, Edinburgh, October 1995,
2
PP. 60-65 Legarth, J.B. and Alting, L. Demands on industry in sustainable use of metal resources, Proceedings of the 1995 ASME International Mechanical and Engineering Congress and Exposition, San Francisco, November, 1995 Meadows, D.H. et al,, The Limits to Growth, Universe Books,
7 8
9
10 11
New York, 1972 United Nations, Agenda 21-The United Nations Programme of Action from Rio, 1993 Goeller, H.E. and Zucker, A. Infinite resources: the ultimate strategy, Science, 1984, 223, 456 Legarth, J.B. Recycling of electronic scrap, Ph.D. dissertation AP 96.08, IPT.96.08-A from the Department of Manufacturing Engineering, The Technical University of Denmark, 1996 United Nations, Long Range World Population Projections 1950-2150, 1992 Weterings, R.A.P.M. and Opschoor, J.B. The eco-capacity. as a challenge to technological development, RMNO publication No. 74a, The Netherlands, 1992 Metallstatistik, published annually by the German Metallgesellshaft, various years Jovane, F. et al. A key issue in product life cycle: disassembly, Annals of the CIRP, 1993, 42(2), 651 Ullmann’s Encyclopedia of Industrial Chemistry 5th edn., 1986, vol A7, p. 472