Iron ore and steel production trends and material flows in the world: Is this really sustainable?

Resources, Conservation and Recycling 54 (2010) 1084–1094

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Iron ore and steel production trends and material flows in the world: Is this really sustainable? Mohan Yellishetty a,∗ , P.G. Ranjith a , A. Tharumarajah b a b

Department of Civil Engineering, Monash University, Clayton 3800, VIC, Australia CSIRO Material Sciences & Technology, Highett, Melbourne, VIC, Australia

a r t i c l e

i n f o

Article history: Received 2 October 2009 Received in revised form 26 February 2010 Accepted 4 March 2010 Keywords: Iron ore Iron and steel Material flow Substance flow Specific energy and sustainable development

a b s t r a c t Material flow analysis is an analysis of the flow of a material into and out of a particular region. The flow analysis also includes estimation of energy expended and of environmental emissions at each stage of the material life cycle, i.e. from extraction, processing, consumption and recycling to disposal. This analysis informs resource policy, energy planning, environmental and waste management. This paper reports on a historical material flow analysis of the world iron ore and steel industry in which the material flow of iron ore and of crude steel products are quantified for the period from 1950 to 2005. On the basis of this analysis, the future production of iron and steel for the world is estimated. The historical analysis shows that the world iron ore production increased from 274 million tons (Mt) in 1950 to 1554 Mt in 2005, whereas the steel production increased from 207 to 1259 Mt. In addition, it is found that at the current level of production the world’s identified iron ore reserves containing 230 billion tons of iron would last for nearly 50 years. Global CO2 emissions from steel production from the different manufacturing routes are estimated to be 3169 Mt from approximately 1781 Mt of steel production by 2020, whereas the specific energy consumption is estimated to be 14.43 GJ/tcs. The analysis of historical production trends of iron ore and crude steel for the major iron ore and steel producing countries indicates that, incidentally, the major iron ore producing countries are not the major steel producing countries and vice-versa. For example, in 2005, Brazil’s iron ore production was 322 Mt whereas its steel production was approximately 10% of its iron ore production. For the same period, Japan’s steel production was 124 Mt though; it had no domestic iron ore production. The world flows of iron ore and steel clearly indicate that the weak end of the iron and steel industry is the time, cost and environmental emissions associated with the sea borne transport of materials. Further, a substance flow model for the year 2006 indicating the net flows of iron ore, crude and finished steel products across the continents demonstrates that these flows of materials is not environmentally sustainable, and the iron and steel sector could do a lot to contribute to sustainable development. © 2010 Elsevier B.V. All rights reserved.

1. Introduction Material flow analysis (MFA) is an analysis of the flow of a material into and out of a particular region. The MFA can be used as a tool to estimate the loss of materials and the environmental impacts during various processes in its life cycle. According to different subjects and various methods, MFA covers approaches such as substance flow analysis (SFA), product flow accounts, material balancing and overall material flow accounts. MFA and SFA both invoke mass conservation to track the fate of materials and to evaluate the environmental burdens they carry with them as they move through their life cycles (Spatari et al., 2003).

∗ Corresponding author. Tel.: +61 3 99058901; fax: +61 3 99054944. E-mail address: [email protected] (M. Yellishetty). 0921-3449/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.resconrec.2010.03.003

MFA has been used to estimate stocks of metals in society and the emissions and losses from anthropogenic engine reservoir (Maag et al., 1997; Sorme, 1998). Some work has comprehensively examined emissions and losses as well as the mechanisms of those losses (Landner and Lindestrom, 1999; Van der Voet et al., 2000). Many researchers have studied either country or global level material cycles for specific substances such as copper, cadmium, mercury, steel and zinc have been carried out in the last decade (Jolly, 1993; Thomas and Spiro, 1994; Jasinski, 1995; Zeltner et al., 1999; Gorter, 1997; Michaelis and Jackson, 2000a,b; Spatari et al., 2002; Reclade et al., 2008; Wang et al., 2007; Xueyi and Yu, 2008). Their studies have advanced our understanding on various anthropogenic material cycles and thereby providing with solutions to optimise their production, use and recycling. MFA plays an important role in the industrial metabolism and the life cycle assessments (Xueyi and Yu, 2008). Through MFA, we can control the inputs and the direction of noxious materials, and

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analyse the amount and intensity of use of the substance, so as to offer new method and view for the environmental policy. Results from the study of SFA are a good guidance for the policy and practice of industry and environment. It is of increasing importance, for both economic and environmental reasons, to establish the flow of energy and materials associated with such resources and to identify any opportunities for resource conservation and environmental improvement that may present themselves (Michaelis and Jackson, 2000a,b). The main objective of this paper is to develop a global 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. This model is based on the historical statistical data extracted from various government organisation, industry association and individual industry annual reports. 2. Methodology and data sources This section of the paper will explain the methodology employed in constructing regional and country-level contemporary iron ore and iron and steel (herein after referred to as steel) flows and various data sources used. Mass flow modeling of iron ore and steel from the year 1950 to 2005 was built around the net shipments data provided by the following government, semigovernment and industry supported associations. The data was gathered starting in year 1950 through 2005 into a comprehensive spreadsheet model by year, by region (North America, South America, Europe, etc.) and by country (Australia, Brazil, China, etc.). Modeling of future and resources flows was based on the regression analysis of the historical statistical data obtained from the sources listed below. The global iron ore and steel mass flows model was based on the data from worldsteel association (worldsteel) in the world for the year 2006 (Worldsteel, 2007). In this paper, mostly the statistics are expressed in metric tonnes unless otherwise mentioned specifically. In this paper the discussions focus only on few selected countries/regions, such as Australia, Brazil, China, Europe, India, Japan, Russia, Ukraine, USA and the world as these countries contribute to more than 85% of world steel production and hence are assumed to represent the trends of the rest of the world. The CO2 emission projections (non-energy) were based on the empirical formula recommended by the European Commissions’ draft reference document on best available techniques for the production of steel (European Commission, 2001). Whereas, the CO2 emission projections (energy) were based on the power consumption data from different industry associations and individual companies and for the energy related emission factors we have used different steel producing countries national grid averages. Specifics about individual data sources are explained below: 1. World iron ore production statistical information (from 1950 to current): (IBISWorld Industry Report, 2009; USGS, 2008; British Geological Survey, 2008; Worldsteel, 2007; Kirk, 2000; Kesler, 1994; Wilshire et al., 1983). 2. World steel production statistical information (from 1950 to current): (ISSB, 2008; Worldsteel, 2007; Fenton, 1999; Wilshire et al., 1983). 3. Energy use in steel industry: (for Australia: BlueScope Steel, 2009; Brazil, China and Japan: Kim and Worrell, 2002; Worrell et al., 1997; Europe: UK Steel, 2008; Worrell et al., 1997; India: TATA Steel, 2009; and North America: Steel Recycling Institute, 2009; Worldsteel, 2009a,b; American Iron & Steel Institute, 1997). 4. Energy use and greenhouse gas emissions data for iron ore operations: for Australia, Brazil and Canada: Rio Tinto (2009); for Australia: BHP Billiton (2009); for India: SAIL (2009).

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Table 1 List of iron bearing minerals (source: GSA, 2009 and Lepinski et al., 2001). Mineral

Chemical composition

Iron content

Hematite Geothite Ilmenite Magnetite Siderite Pyrite

Fe2 O3 HFeO2 FeTiO3 Fe3 O4 FeCO3 FeS2

70 62.85 36.8 72.4 48.2 46.6

3. World resources of iron ore 3.1. Overview of iron ore mining industry Iron is an abundant element in the earth’s crust averaging from 2 to 3% in sedimentary rocks to 8.5% in basalt and gabbro, which ranks iron the fourth abundant element in the earth’s crust (GSA, 2009). Because iron is present in many areas, it is of relatively low value and thus a deposit must have a high percentage of metal to be considered ore grade. Typically, a deposit must contain at least 25% iron to be considered economically recoverable. This percentage can be lower, however, if the ore exists in a large deposit and can be concentrated and transported inexpensively (Weiss, 1985). Most iron ore is extracted in opencast mines in the world, carried to dedicated ports by rail, and then shipped to steel plants around the world, mainly in Asia and Europe. Further, iron accounts for approximately 95% of all metals used by modern industrial society (GSA, 2009). Over 300 minerals contain iron but five are the primary sources of iron ore minerals: magnetite (Fe3 O4 ), hematite (Fe2 O3 ), goethite (Fe2 O3 H2 O), siderite (FeCO3 ), pyrite (FeS2 ). Among these, the first three are of major importance because of their occurrence in large economically minable quantities (US EPA, 1994). Some important iron ore minerals are listed in Table 1. The most important use of iron ore (up to 98%) is as the primary input to steel making with the remainder used in applications such as coal washeries and cement manufacturing (Indian Bureau of Mines, 2007; IBISWorld Industry Report, 2009). The demand for iron ore is therefore heavily dependent on the volume of steel production. 3.2. World iron ore reserves Many attempts have been made to assess the world’s resources in iron ore (CEC, 1965; Cook, 1976; Muller et al., 2006; USGS, 2008), and they vary within wide limits. The main reasons for this being either the geological survey work has not been done or the basis of assessment being different in different countries. The United States Geological Survey (USGS) estimates put the known world reserves of iron ore, recoverable economically with the existing technology, at more than 165,347 Mt, which means at current level of production these reserves would last 79 years (USGS, 2008). The largest reserves are in Australia, Brazil, China, Russia and Ukraine (Table 2). 3.3. World iron ore production trends Ever since the onset of industrial revolution in the west, the use of the steel has become indispensable part of the development process. This is clearly demonstrated by the ever increasing demand for the steel and consequently the iron ore production. Although iron ore production was widely distributed, taking place in about 48 countries (Jorgenson, 2008), the bulk of world production came from just a few countries. The five largest producers in the year 2007, in decreasing order of production of gross weight of ore, were China (33%), Brazil (18%), Australia (15%), India (8%) and Russia (6%). Ukraine, the United States and Canada were ranking sixth, seventh

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Table 2 Iron ore reserves and reserve base in the world (source: USGS, 2008). Description

Crude ore (Mt (short)) a

b

R Australia Brazil China India Russia Ukraine USA World a b

Ra

RB

17,637 17,637 23,149 7,275 27,558 33,069 7,606 165,347

Iron content (Mt (short))

49,604 29,762 50,706 10,803 61,729 74,957 16,535 374,786

RBb

11,023 9,811 7,716 4,630 15,432 9,921 2,315 80,469

30,865 15,432 16,535 6,834 34,172 22,046 5,071 176,370

Reserves. Reserve base.

Table 3 Production of iron ore in the major iron ore producing countries of the world. Country

Australia Brazil China India Russia Ukraine USA World

Mine production (Mt (short)) 2006

2007

303 351 648 154 112 82 58 1984

353 397 661 176 121 84 57 2094

Fig. 1. Actual and projected iron ore production in the world.

%Production in 2007

15.27 17.69 32.66 7.76 5.65 4.13 2.92

and eighth in iron ore production for the same period (Table 3). The top five accounted for 80% of world production (Table 3). The world iron ore production has been steadily increasing since 1950 until 2005 and it is expected to increase exponentially in the coming future (Fig. 1). Currently, China is clearly driving global demand for iron ore, being the largest and fastest growing market for seaborne trade in iron ore. Following its footsteps are the other developing countries like Brazil, Russia, Ukraine and India, where there has been growing demand for steel, primarily from infrastructure projects. Fig. 1 shows the historical and projected iron ore production trends. This projected production seem to be fairly in good correlation to the reported worldwide iron ore production data for 1950–2005 (R2 = 0.86). So, the model estimates required future iron ore production to the year 2030, which is expected to be 2883 Mt. From the data presented in Fig. 1 an empirical relationship, assuming the iron ore production to continue at an exponential rate, to estimate the production of iron ore at time t has been established, and the same is expressed in Eq. (1). P(t) = aekt or = Aek(t−2000)

(1)

where P(t) = production of iron ore (Mt), a = constant (2 × 10−18 ), k = production coefficient/depletion coefficient (0.024), t = the year, A = 1403.34 (production in the year 2000 as base year). From the above equation, the estimation of iron ore reserves at any time in the future can be made by using Eq. (2). According to Tilton and Lagos (2007), reserves can be defined as the ‘the metal contained in deposits that are both known and profitable to exploit given the metals’ price, state of the technology, and other conditions that are currently existing’.



R(t) = R2006 − Ae7k

e(t−2006)k − 1 ek − 1

main shortcoming in those estimates was that, while estimating the depletion times, they assumed the production of iron ore to be at the same rate as it was in 2006, and then divide the known reserves by the production in 2006, which gave the life expectancy of reserves in each country and the world. Whereas, the empirical model proposed in this paper (Eq. (2)) assumes that the iron ore production to go up at an exponential rate and to be same for all the countries (in reality each country has different growth patterns). Therefore, subtracting individual year production from the net reserves at the beginning of each year would give the total reserves left at the end of each year and accordingly with that rate of production the depletion times could be estimated. Many a times, these estimates have been proved to differ from what are actually found. This could be due to increasing the efficiencies of exploration, recovery and processing technologies we have been able to find and exploit low-grade, deeper and more remote deposits economically. By discovering and developing new methods of utilizing previously worthless materials, we have created resources where none existed (Yaksic and Tilton, 2009; Tanzer, 1980; Cook, 1976). 3.4. Iron ore mining industry and environmental sustainability Sustainable development (SD) according to ‘Our Common Future’ means “the development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (WCED, 1987). Following this, there have been several reviews which focused on sustainability and its application to minerals industry (ICMM, 2008; Mudd, 2007; Atherton and Davies, 2005; MMSD, 2002; Meadows et al., 1972). According to Michaelis and Jackson (2000b) moving towards SD in the minerals industry represents a great challenge for two main reasons. In the first place, environmental sustainability demands the conservation and sustainable management of finite mineral resources-the same resources on which the primary resource industries currently rely Table 4 Estimated depletion time of iron ore reserves in the world. Country



Life expectancy in years According to USGS method

(2)

where t = year; k = depletion coefficient (0.024); R(t) = remaining quantity of iron ore reserves at time t. Table 4 presents the results of iron ore resource depletion timeframes calculated by Eq. (2). This compares our estimates with those estimated by the Muller et al. (2006) and USGS (2008). The

Australia Brazil China India Russia Ukraine USA World

50 44 35 41 227 395 133 79

Estimated (using Eq. (2)) 33 30 22 28 77 99 56 49

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Fig. 2. (a) CO2 emissions and water consumption; (b) power consumption associated with iron ore production.

for their own financial sustainability. In the second place, extraction and processing of mineral resources is both energy intensive and environmentally damaging, placing an additional pressure on primary resource industries to improve environmental performance. Assessment of sustainability in the case of mining requires the knowledge of SD indicators, such as production trends, number of jobs created, amount of power, fuel, water used, solid wastes generated, land rehabilitated and health and safety issues. In this paper we have quantified some of such SD indicators with respect to iron ore mining operations. The critical limitation in this is the availability of data from various organisations. List of data sources used in this paper have been discussed in the previous section and all the references are to the respective company environmental or sustainability reports. While it includes the data from wide geographic spread of mines in Australia, Brazil, Canada and India, covering significant world iron ore production, it does not include the data for China, Europe, Russia, Ukraine and USA. In Fig. 2(a) and (b) specific energy, water consumption and CO2 emission data in respect of iron ore production is presented. The data presented is an average of iron ore mining operations from India, Australia, Brazil and Canada. These operational performance indicators will provide a company and its communities of interest with a good picture of the energy consumed on a year to year basis and consequential GHG emissions, and the success of efforts to improve energy and emissions intensity. Because mining is an energy intensive industry, energy efficiency is the key in sustaining the international competition. Among the energy efficiency challenges for mining operations today is the fact that older and deeper mines require more energy, water and other materials for extraction and the release of emissions and wastes (Schandl et al., 2008) to access and extract the ore. Some 95% of the mining industry’s GHG emissions are associated with the combustion of fossil fuels. Therefore, it is true that ‘to the extent companies can improve their energy efficiency; they will improve their GHG emissions intensity’ (The Mining Association of Canada, 2007). The world iron ore mining industry’s GHG emissions are almost exclusively linked to energy consumed, burning of fossil fuels and removing of vegetation during the production process and provides an environmental challenge for the industry (The Mining Association of Canada, 2007). 4. Steel manufacturing trends in the world 4.1. Steel production technologies Steel production can occur at an integrated facility from iron ore or at a secondary facility, which produce steel mainly from recycled steel scrap. Integrated facility typically includes coke production,

blast furnaces, and basic oxygen steelmaking furnaces (BOFs), or in some cases opens hearth furnaces (OHFs). Raw steel is produced using a basic oxygen furnace from pig iron produced by the blast furnace and then processed into finished steel products. Secondary steelmaking most often occurs in electric arc furnaces (EAFs). A brief description about each of the steel manufacturing technologies is presented in the subsections below. 4.1.1. Basic oxygen furnace technology Steel production in a BOF begins by charging the vessel with 70–90% molten iron and 10–30% steel scrap. Industrial oxygen then combines with the carbon in the iron generating CO2 in an exothermic reaction that melts the charge while lowering the carbon content. The charge is already melted as the pig iron is coming from the blast furnace. Scrap is added to reduce the temperature. 4.1.2. Electric arc furnace technology Steel production in an EAF typically occurs by charging 100% recycled steel scrap, which is melted using electrical energy imparted to the charge through carbon electrodes and then refined and alloyed to produce the desired grade of steel. Although EAFs may be located in integrated plants, typically they are stand-alone operations because of their fundamental reliance on scrap and not the iron ore as a raw material. Since the EAF process is mainly one of melting scrap and not reducing oxides, carbon’s role is not as dominant as it is in the blast furnace-OHF/BOF processes. In a majority of scrap-charged EAF, CO2 emissions are mainly associated with consumption of the carbon electrodes. 4.1.3. Open hearth furnace technology Open hearth furnace (OHF) is where excess carbon and other impurities are burnt out of the pig iron to produce steel. OHF was developed to overcome some of the difficulties faced in steel production until that time. However, most OHFs woldwide were closed by the early 1990s, because of their fuel inefficiency and resource intensity, and are being replaced by the BOF. 4.2. Steel production trends in the world In this section we discuss the results of the analysis focusing on steel production trends in the world and the methodology of forecast for the future years. In 2005, BOFs accounted for approximately 65% of world steel production and EAFs approximately accounted for 32%; OHF production accounted for the remaining 3% (Table 5), but is today declining. China has the highest share of BOF steel production whilst the USA has highest share of EAF steel production and Ukraine has highest open hearth furnaces steel production (Table 5 and Fig. 3).

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Table 5 Shares of main steel production processes in selected countries. Country/region

Basic oxygen furnace (%)

Electric arc furnace (%)

Open hearth furnace (%)

Australia Brazil China EU India Japan Russia Ukraine USA World

82.18 76.15 85.56 57.86 48.95 74.35 61.61 49.95 45.00 64.75

17.79 22.02 12.63 42.12 41.80 25.65 16.33 9.83 55.00 31.54

Nil Nil Nil Nil 2.45 Nil 22.07 40.24 Nil 2.79

analysis, we have projected the trends in steel production to the year 2030 with the coefficient of determination (R2 = 0.88, exponential regression). From the estimates it could be understood that both BOF and EAF route steel productions are increasing exponentially (R2 values of 0.87 and 0.92). It can also be seen that, by 2015, the OHF steel production technology is becoming obsolete, mainly due to its own drawbacks of low efficiency and excessive environmental emissions (R2 = 0.62, linear regression). In the case of EAF production, however, it should be noted that most steel products remain in use for decades before they can be recycled. Therefore, there is not enough recycled steel to meet the growing demand by using the secondary steelmaking method. Thus, the demand for steel requirement is met through a combined use of the primary and secondary production methods. 4.3. Steel production and environmental impacts Steel is worlds’ 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 come across in our day-to-day life. The steel industry is one of the major industries, which consume huge quantities of energy and therefore it is liable to cause environmental degradation, mainly due to greenhouse gas emissions. With the Kyoto Protocol entering into force, greenhouse gas emissions and climate change continue to be significant environmental issues for the steel industry (IISI, 2005). In the following sections we deal with environmental issues related to steel industry.

Fig. 3. World steel production trends and projections.

Based on the historical production data of steel through different production routes, future steel production projections were made (Fig. 3). As can be seen from the historical production trends, some figures in the total production were not split by furnace type. This is because of absence of production data split by furnace type for one or more countries in the past. Through the use of regression

4.3.1. Energy consumption in the steel industry This section will explain the methodology employed in calculating the specific energy consumption associated with the steel industry. The steel industry presents one of the most energy intensive sectors within any country’s economy and is therefore of particular interest in the context of both local and global environmental discussions. So much so that in the U.S. steel producers combined used more than 3% of total U.S. energy consumption and more than 10% of that used by the whole manufacturing

Fig. 4. Steel production routes and energy intensities (modified from: Worldsteel, 2009b).

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Fig. 6. World CO2 emission from steel production (energy and non-energy sources). Fig. 5. Actual and projected specific energy consumption in the steel industry (world average).

sector (Fenton, 2005) and the energy is the largest single component of operating costs for many producers (20–40%). Fig. 4 shows a schematic of the steel production technologies and associated energy intensities in GJ/t of crude steel produced (Worldsteel, 2009b). The world steel industry has taken enormous strides over the past five decades to reduce its specific energy consumption (SEC) (energy use per ton of crude steel produced). However, the energy efficiency varies depending on production route, type of iron ore and coal used, the steel product mix and material efficiency (Worldsteel, 2009b). In the context of this paper, the world average to be treated as average SEC data from the steel producing countries: Australia (1996–2008), Brazil (1980–1991), China (1980–1991), Europe (1974–2007), India (1977–2005), Japan (1980–1991) and USA (1950–2008). Fig. 5 presents both actual and predicted values. The SEC for steel production in the seven countries is calculated by dividing primary energy consumption in the steel industry by total crude steel production. The correlation coefficient for energy consumption was well within the acceptable limits (R2 = 0.85) (exponential regression). Since the 1950s, the world steel industry has reduced its SEC by 85% (Fig. 5). Between 1990 and 1998 alone, the average SEC has dropped from 31 GJ/tcs produced to 21 GJ/tcs. This figure is projected to decrease to 14.5 and 12 GJ/tcs by the year 2020 and 2030, respectively. It clearly shows a considerable reduction in the world average SEC in steel production, falling from a maximum of 63 GJ/tcs in 1950 to the 2005 value of 18 GJ/tcs. This reduction occurs as a result of reductions in the energy consumption per ton of output within each process; substitution of BF/OHF process by the less energy intensive BF/BOF; improvements in BF/BOF and EAF, improvement in manufacturing the semi-products, improved scrap collection and sorting. Thus, any improvement in energy efficiency would benefit the steel industry in mitigating air emissions (CO2 ). 4.3.2. Global CO2 emissions related to steel production This section will discuss the results related to calculation of the CO2 emissions associated with the steel production worldwide. Fig. 6 presents world estimate of historical, current and future CO2 emissions due to steel production from both energy and nonenergy sources. Based on actual production data available for the period 1950–2005 projections of total CO2 emissions were determined in two steps. In the first place, the CO2 emission estimates were made in respect of non-energy sources using the empirical equation proposed. Secondly, the CO2 emission estimates were made in respect of energy usage in steel industry and the detailed methodology has been discussed in the following paragraphs.

However, while calculating the CO2 emissions as a result of steel production, these estimates assume emission factors of national electricity grid supplies of the countries under study. In calculating the amount of electricity equivalents of energy, an energy conversion efficiency of 33% was assumed. This critical limitation of these estimates must be considered. By this estimate, the historical emissions are likely to have been underestimated as it presumes emission rates base on current technology, which is more efficient than it was in the past. While future emissions are likely to have been over estimated as they are also based on current emission factors and do not take into account scientific advances that will curb the CO2 emissions in electricity generation and in iron and steel production, and is based on the business-asusual methodology. CO2 emissions associate with steel production through non-energy sources was estimated using Eq. (3) proposed by 2006 IPCC Guidelines for National Greenhouse Gas Inventories (IPCC, 2006; Lubetsky and Steiner, 2006; European Commission, 2001). CO2 emissionsnon

energy

= BOF × EFBOF + EAF × EFEAF + OHF × EFOHF (3)

where CO2 emissions (non-energy) = emissions of CO2 to be reported in tons; BOF = quantity of BOF crude steel produced, tons; EAF = quantity of EAF crude steel produced, tons; OHF = quantity of OHF crude steel produced, tons; EFx = emission factor, tons CO2 /ton x produced. Another important assumption in this model was that of remainder of crude steel produced (which is total crude steel in a year less the crude steel produced through BOF, OHF and EAF routes for that year). This fraction of steel was assumed to have been produced as a combination of BOF (65%), OHF (5%) and EAF (30%) routes and accordingly the emission factor for this combination was used in calculations (1.06 ton of CO2 /ton of crude steel produced). This is because some steel producing countries have accounted their historical crude steel (total), but the data on individual production routes was not reported (BOF, EAF and OHF). In order to calculate the CO2 emissions as a result of energy use, we first multiplied the crude steel production (Mt) figures by the average SEC (GJ/tcs) in that year, which gave the industries’ total energy consumption per year (GJ/year). In the next step, the world’s weighted average energy emission factors for 1950–2005 were calculated with 5-year increment. Then, these weighted average CO2 emission factors (world) were used in calculating the resultant CO2 emissions of energy use in the steel industry. The emission factors in respect of individual countries for calculating the world’s weighted average were assumed to be: Australia (0.855); Brazil (0.057); China (0.839); Europe (0.476); India (0.963); Japan (0.43); Russia (0.321); Ukraine (0.387); USA (0.745 kg CO2 -e/kWh). Finally,

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Fig. 7. Historical trends in production of iron ore and crude steel in the major producing countries of the world.

the total energy consumption (GJ) was multiplied with their respective emission factors (world’s weighted average) (tons of CO2 -e/GJ of energy use), which gave the total CO2 emissions due to steel production worldwide (Mt CO2 -e) (see Fig. 6). According to our model, in 2005, the worldwide steel production resulted in 2613 Mt of CO2 -e emissions from 1140 Mt of steel production from both energy and non-energy sources. This is more than two times higher than the levels of 1950. In 1950 the CO2 -e emissions were estimated at 913 Mt from 188 Mt of steel. Although, since 1950 the world steel production has increased by

more than fivefold the CO2 emissions have not proportionately increased, which means worldwide steel production is becoming less energy and GHG intensive. This model also estimates the steel industry’s CO2 emissions by 2010, 2020 and 2030, which are estimated to be 2716, 3169 and 3763 Mt, respectively (Fig. 6). This reduction is because of multiple reasons. One reason for this being the EAF steel production is expected to grow rapidly as a percent of total crude steel production by the year 2030, and another reason being reduced energy intensity in the steel industry (Fig. 5). According to the model, it is estimated that the effective

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reduction in CO2 emissions between 2005 and 2010 would be at 103 Mt. 4.4. Iron ore and steel production trends in the major producing countries In this section of the paper we present a discussion on the trends in iron ore and steel production in either major iron ore producing or steel producing countries. In the year 2005, iron ore was produced in 45 countries, with production exceeding 1 Mt, gross weight, in 26 of those countries (Jorgenson, 2008). In the same year, the world iron ore production was 1.6 Gt (gross weight). World production has been more than 1 Gt (gross weight) since it first exceeded that level in 1995. World crude steel production surpassed 1.2 billion metric tons (Gt) and rose by 9% from 2005 to 2006. Four countries accounted for 5% or more of world production in 2006. Of those countries, China produced almost 100 Mt more crude steel in 2006 than in 2005. The others (Japan, Russia, and the United States) combined produced 12 Mt more crude steel in 2006 than in 2005. The world crude steel production, excluding that of China, has increased by almost 35 Mt annually. Unlike other major producers of iron ore in Europe and the USA, which consumes most of their own production for their domestic purposes, the real dominance is by producers like Australia and Brazil, which are mainly the exporters. Australia, Brazil and China are now the world’s leading exporters of iron ore. A major contributing factor for this is cheaper seaborne transportation due to development of bulk carriers and their ore grades. These transportation savings enabled both Australia and Brazil to compete in European and Japanese markets, respectively. Iron ore and steel production, as shown in Fig. 7(a)–(i) varied in the selected countries over the study period (1950–2005). Australia and Brazil’s combined share of world iron ore production from 2002 to 2005 averaged 35%. On the other hand, historically, Japan has been the single largest importer of iron ore although it had negligible to zero domestic iron ore production. Japan’s steel production rapidly increased from 5.3 Mt in 1950 to 124 Mt in the year 2005, so did its iron ore requirement. For most years in the case of Europe, Japan and the USA, the iron ore production was declining. In contrast, the steel production has been increasing ever since. In 1950, the USA and Europe combined share of iron ore production was 75%, but the same in 2005 was only 7% of world total. A similar trend is observed in their steel production. In 1950, the combined share of steel production was 78% and the same in the year 2005 was just 28%. Brazil had increasing trend in iron ore production in the study period whilst its steel production growth was marginal. Its iron ore production rose from 2.9 Mt in 1950 to 322 Mt in 2005, in contrast its steel production grew from 0.79 to 31.61 Mt (Fig. 7a). Similarly, Australia’s iron ore production rose from 2.64 to 284 Mt, but its iron ore production remained steady for the decade 1975–1985. Whereas, for the same period the steel production grew from 1.28 to 7.76 Mt (Fig. 7b). China’s iron ore production rose from 2.20 to 470 Mt, whilst its steel production rose from 0.61 to 356 Mt (Fig. 7c). India recorded an increase from 3.31 to 160 Mt in iron ore production whereas its steel production rose from 1.46 to 41 Mt (Fig. 7d). Much of the iron ore production from Australia, Brazil and India was mainly for export, which is driven by Japan, Korea and of lately from China. Currently, in steel production, China clearly is driving the global demand as the fastest growing market. However, it is a bit of a strange concept when you think about steel as a globally traded commodity. In Australia and Brazil, there are very large quantities of iron ore and metallurgical coal, much of which is exported to China and Europe rather than producing

Fig. 8. Normalised production trends of steel in the selected countries.

steel itself, which is environmentally and economically ludicrous and unsustainable (Fig. 7a and b). Australia also has a small population from which the scrap can arise, which is limiting factor for recycled steel production (EAF route). Therefore, it is more logical for Australia and Brazil to produce and export primary steel and to use most of the scrap arising to prime and control its primary steel production. In other countries with high population density and little to no mineral resources (countries like Japan and Europe), it is logical to service its own economy by comprehensive recycling of steel scrap and topping up demand with imports of primary steel (Fig. 7h and i). By all means, it is a bit strange proposition, whether environmentally or economically, for Australia and Brazil to import secondary steel (steel scrap). Although, Russia and Ukraine did not exist as an independent states, and were very much part of erstwhile the USSR before 1992, the production data for iron ore and steel were extrapolated (approximated) from the data of the USSR (Fig. 7e and f). Both these countries exhibit consistency (by maintaining right balance) in iron ore and steel production trends. Russia’s iron ore production was 23 Mt in 1950 and the same in 2005 was 106 Mt whereas the steel production increased from 16 to 66 Mt. On the other hand, Ukraine increased its iron ore and steel productions from 17 to 76 Mt and 10 to 39 Mt, respectively from 1950 to 2005. It can also be noted that after the fallout of the then USSR in 1991, these countries have had a sharp drop in the iron ore and steel production. However, since 1995 the production trends in these countries were on rise and are expected to increase as there are several of infrastructure projects to be underway in most of these developing countries.

4.4.1. Steel production ratios In Fig. 8 country wise steel production data normalised to iron ore production is presented. This clearly exemplifies the case of how environmentally unsustainable are our production trends. For example, in the year 2005 Brazil’s iron ore production was 322 Mt whereas the steel production was 32 Mt, and similarly, Japan’s steel production was 124 Mt although it had no domestic iron ore production and the ratio tending towards infinite. On the one hand, Europe and Japan have very high production ratios-being the topmost steel producing countries and on the other hand Australia and Brazil exhibit a contrasting tendency. This tendency in production needs to be looked into immediately and an appropriate mechanism be developed, which will be in the best interest of our climate. By doing so, the world steel industry would have contributed more towards sustainable development and thus will achieve material stewardship.

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Fig. 9. Iron ore and steel material mass flows in the world for the year 2006 (tonnages in short tons).

Table 6 Percent change in production of steel and iron ore in the period 1950–2005. Average percent change per every 5 years (1950–2005) Material

World

Europe

Ukraine

USA

Brazil

China

India

Australia

Japan

Russia

Iron ore Steel

18.30 18.75

−5.56 14.17

19.85 18.99

−4.62 1.81

65.65 42.99

113.81 122.48

48.06 38.12

95.54 21.17

−11.58 42.07

18.78 17.45

4.4.2. Capacity changes in iron ore and steel production International trade in iron ore has been increasing ever since the onset of industrialisation in the west, but individual countries have either grown or contracted in their productions at widely varying rates. Average per cent change in production of iron ore and steel for the period from 1950 to 2005 is presented in Table 6 (5 year average). It can be seen that the world production of iron ore and steel has steadily increased at the rate of 18.30 and 18.75% every 5 years. However, production trends are not consistent across the major iron ore and steel producing countries around the world. For example, developed countries like Europe, the USA and Japan have had negative growth rates in iron ore production whilst their steel production rates were approximately 14.17, 1.81 and 42%, respec-

tively. The case of Australia has been an exception to this, which maintained positive growth rate, both in iron ore and steel production (95.54 and 21.17%). On the other hand, in most developing and transition economy countries like Brazil, China, India, Russia and Ukraine there has been a positive growth rate both in iron ore and steel production (Table 6). And, it is expected that this growth rate is expected to go up as it would demand more and more iron ore, in some cases exponentially, to cater to the ever increasing requirements of steel industry worldwide. 4.4.3. Substance flows and sustainability issues Fig. 9 shows the overall mass flows in the world’s steel sector. The data on this map are the imports and exports of iron

Table 7 Iron ore and steel trade of USA in 2006. Iron ore exports (short tons) from USA

Iron ore imports (short tons) to USA

Steel exports (short tons) from USA

Steel imports (short tons) to USA

To country

Quantity

From country

To country

From country

Algeria Canada China Colombia Mexico Others

375 8,389 110 10 236 2

Australia Brazil Canada Chile Finland Greece Mexico Peru Trinidad Venezuela Others

Total

8270

Quantity 9,000 4,993,000 6,878,000 312,000 10,000 17,000 19,000 57,000 330,000 25,000 1,000

12,677,000

Argentina Australia Brazil Canada China EU Germany Japan R. of Korea Mexico South Africa Sweden Taiwan Venezuela Others

Quantity 3,828 14,050 40,433 6,095,780 98,411 383,691 47,418 25,833 51,968 2,204,622 10,883 4,694 17,539 60,064 664,694

9,733,406

Argentina Australia Brazil Canada China EU Germany Japan R. of Korea Mexico Russia South Africa Sweden Taiwan Turkey Ukraine Venezuela Others

Quantity 163,304 1,168,450 2,899,078 5,952,479 5,390,301 6,272,150 1,344,819 2,105,414 2,799,870 3,637,626 3,637,626 469,200 281,230 1,873,929 2,403,038 1,752,674 198,012 2,943,170 45,304,982

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ore, scrap, semi-finished and finished steel product flows into and out of a particular region. Although actual data on consumption of iron ore and steel in many cases are incomplete or not available, an approximate estimation about apparent consumption was calculated (production plus imports less exports). For example, in 2006, 585 Mt of iron ore was imported into Asia while 99 Mt was exported when the domestic production was 491 Mt, which means, the apparent consumption to be 976 Mt (apparent consumption = production + imports − exports). Similarly, steel production was 745 Mt with imports of 114 Mt (steel), 29 Mt (scrap) and 5 Mt pig iron, whilst exporting 147 Mt (steel), 13 Mt (scrap) and 2 Mt (pig iron). Countries (companies) export because they have excess capacity and can make a profit by exporting it rather than adding it to their stock whereas they import because they can buy it cheaper elsewhere or they cannot get it from their own country. These figures are total iron ore and steel figures though, while a country may export billet or bars and import wire for example, depending on where it is produced most cheaply. These world flows of iron ore and steel clearly indicate that the weak end of steel industry’s trade is the sea borne transport, which is also a major environmental challenge for today’s steel industry. Even as the seaborne transport became very convenient and economic alternative for the intercontinental mass movement of goods at very marginal added costs-making it financially sustainable-the real issue is of its environmental sustainability in longer term. This is of greater concern particularly in the context of present challenges posed to our global climate and its anticipated vicious effects. Therefore, the main question remains is that ‘can we continue to operate the way we have been doing for centuries now?’ In Table 7 we have presented the case of the USA wherein the mass flows of iron ore and steel (includes crude, finished and semifinished products) into and out of the USA and different countries are presented. Similarly, in 2006 Japan imported iron ore from more than 12 countries, steel from more than 20 countries and exported steel to as many as 46 countries. For example, considering an average emission factor of different sized container vessels/ships to be 23 g-CO2 /t km (0.324 MJ/t km) (arithmetic average) (Baumann and Tillman, 2004), the seaborne transportation itself contributes to an additional 10–15% CO2 emissions (of crude steel production). Therefore, a reduction in logistical expenditure alone could potentially curb CO2 emissions to the tune of 10–15% pa, a significant saving considering the current climate crisis and the size of the global steel market.

5. Conclusions We have presented the analysis of material flows of iron ore and steel in the world. It has been observed that the world iron ore and steel production is increasing exponentially. From our analysis we have also estimated the depletion times of current known iron ore reserves in the selected countries and the world. We have also examined the trends of the world’s energy efficiencies in steel production over time in eight countries. Then, we have analysed the energy consumption of the steel industry for the period 1950–2005. The world steel industry showed a decreasing trend in SEC. The findings reported in this paper indicate that there is a complex inter-relationship between production technologies, consumption patterns and the domestic and global infrastructure of the steel sector. For example, the transition away from OHF towards BOF and EAF has given rise to a reduction in the specific energy consumption of steel production processes. The world flows of iron ore and steel clearly indicates that the weak end of steel industry is the sea borne transport, which is also the major environmental concern for today’s steel industry (contributing additional 10–15% of total CO2 emissions arising out from

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steel production) of the world. Overall, it is clear from this analysis that there should be considerable potential to reduce the overall energy consumption and consequent CO2 emissions associated with the steel sector, in particular by streamlining the mass flows of iron ore and steel. So, until the time the steel industry achieves any process technological breakthroughs (smelt reduction, strip casting, alternative fuels and carbon sequestration), it could focus the attention on streamlining the world flows of materials connected with it. This way the steel industry would have contributed more towards sustainable development. Acknowledgements Mohan Yellishetty would like express his sincere appreciation and profound thanks to Scott Gould, Aidan Sudbury, Gavin M. Mudd and Jane Moodie for their help. Many thanks are also due to Phil Hunt (ISSB Ltd, UK), J. –P. Birat (AM), Peter W. Glazebrook, Barry Jilbert (RTIO), John D. Jorgenson, John F. Papp (USGS), Nigel Howard (BPL) and Michael T. Roche (BHP). He would also like to thank William Darlington, Hilary Luxford and Godwin Vaz. Finally, I would like to acknowledge the very useful suggestions made by the Editor and two anonymous reviewers. References American Iron & Steel Institute. Energy policy–public policy issues; 1997, Available at: http://www.steel.org/policy97/energy.html [accessed on January 11, 2009]. Atherton J, Davies B. Materials stewardship-towards the sustainable use of minerals and metals. In: Plenary paper presented on the occasion of the European metallurgical conference EMC 2005; 2005. Baumann H, Tillman AM. The hitch hiker’s guide to LCA-an orientation in life cycle assessment methodology and application. Lund, Sweden: Studentlitterrature AB; 2004, 501 pp. BHP Billiton. Resourcing the future: sustainability report 2008 (full report). BHP Billiton; 2009. Available at http://www.bhpbilliton.com/bb/ sustainableDevelopment/reports.jsp [accessed on May 15, 2009]. BlueScope Steel. Community, safety and environment reports (2002–08). BlueScope Steel Limited; 2009, Available at: http://www.bluescopesteel. com/go/responsibilities/environment [accessed on July 15, 2009]. British Geological Survey. World mineral statistics dataset 1950–2005. Keyworth, Nottingham, UK: British Geological Survey; 2008. CEC. Iron and steel and alloying metals. A review of resources, production, trade and consumption. London: HER Majesty’s Stationery Office; 1965, Published for commonwealth economic committee (CEC), 221 pp. Cook E. Limits to exploitation of nonrenewable resources. Science 1976;191(4228):677–82 [new series]. European Commission. Integrated pollution prevention and control (IPPC)—best available techniques reference document on the production of iron and steel; 2001, 383 pp. Fenton MD. Iron and steel recycling in the United States in 1998. Open file report. US Geological Survey, US Department of the Interior; 1999. p. 1–224. Fenton MD. Mineral commodity profiles—iron and steel. Open file report (2005–1254). US Geological Survey, US Department of the interior; 2005, 40 pp. Gorter J. Zinc balance for The Netherlands, 1990. In: Material flow accounting: experience of statistical institutes in Europe. Luxembourg: Eurostat; 1997, 205/39. GSA. PIRSA minerals. Government of South Australia (GSA), Primary Industries and Minerals SA; 2009, Available at: http://outernode.pir.sa.gov.au/ minerals/geology/mineral resources/commodities/iron ore [accessed on May 15, 2009]. IBISWorld Industry Report. Iron ore mining in Australia: B1311. IBISWorld Pty Ltd; 2009, 50 pp. ICMM. ICMM sustainable development framework. ICMM principles. International Council on Mining and Metals (ICMM); 2008, Available at: http://www.icmm.com/publications/ICMM Principles en.pdf [accessed on May 15, 2009]. IISI. Steel: the foundation of a sustainable future. In: Sustainability report of the world steel industry 2005 (1782–2025). International Iron and Steel Institute (IISI); 2005, 51 pp. Indian Bureau of Mines. Iron ore—a market survey. Issued by Controller General, Indian Bureau of Mines, prepared by mineral economics division; 2007, 153 pp. IPCC.Eggleston HS, Buendia L, Miwa K, Ngara T, Tanabe K, editors. 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Japan: IGES; 2006, Prepared by the national greenhouse gas inventories programme. ISSB. Iron and steel statistics bureau (ISSB) limited annual statistics. Millbank Tower, London, UK: Iron and Steel Statistics Bureau Ltd., 1974–2007; 2008. Jasinski SM. The material flow of mercury in the United States. Resour Conserv Recycl 1995;15:145–79.

1094

M. Yellishetty et al. / Resources, Conservation and Recycling 54 (2010) 1084–1094

Jolly JH. Materials flows of zinc in the United States, 1850–1990. Resour Conserv Recycl 1993;9:1–30. Jorgenson JD. 2006 minerals yearbook—iron ore. U.S. Department of the Interior, U.S. Geological Survey; 2008 May, 22 pp. Kesler S. Mineral resources, economics and the environment. New York: McMillan College; 1994. Kim Y, Worrell E. International comparison of CO2 emission trends in the iron and steel industry. Energy Policy 2002;30:827–38. Kirk WS. Iron ore-2000. U.S. geological survey minerals yearbook—2000. UGGS; 2000, 19 pp. Landner L, Lindestrom L. Copper in society and in the environment. 2nd revised ed. Vaesteras, Sweden: Swedish Environmental Research Group; 1999. Lepinski JA, Myers JC, Geiger GH. Iron. Kirk-Othmer encyclopedia of chemical technology, vol. 14. John Wiley & Sons Inc. (Pub); 2001, 46 pp. Lubetsky J, Steiner BA. Metal industry emissions. In: Eggleston S, Buendia L, Miwa K, Ngara T, Tanabe K, editors. 2006 IPCC guidelines for national greenhouse gas inventories, vol. 3, industrial processes and product use; 2006, 85 pp. [Chapter 4]. Maag J, Hansen E, Lassen C. Mercury—a substance flow analysis for Denmark. In: Bringezu S, Fischer-Kowalski M, Kleijn R, Palm V, editors. Regional and national material flow accounting: from paradigm to practice of sustainability. Wuppertal Institute for Climate, Environment and Energy; 1997. Meadows DH, Meadows DL, Randers J, Behrens WW. Limits to growth—a report for the club of Rome’s project on the predicament of mankind. London, UK: Potomac-Earth Island; 1972. Michaelis P, Jackson T. Material and energy flow through the UK iron and steel sector (Part 1: 1954–1994). Resour Conserv Recycl 2000a;29:131–56. Michaelis P, Jackson T. Material and energy flow through the UK iron and steel sector (Part 2: 1994–2019). Resour Conserv Recycl 2000b;29:209–30. MMSD. Breaking new ground. Mining minerals and sustainable development (MMSD). Earthscan for International Institute for Environment and Development (IIED); 2002, 441 pp. Mudd GM. Global trends in gold mining: towards quantifying environmental and resource sustainability? Resour Policy 2007;32:42–56. Muller DB, Wang T, Duval B, Graedel TE. Exploring anthropogenic iron cycles. Proc Natl Acad Sci USA 2006;103(44):16111–6. Reclade K, Wang J, Graedel TE. Aluminium in-use stocks in the state of Connecticut. Resour Conserv Recycl 2008;52:1271–82. Rio Tinto Iron. Reports and publications-sustainable development reports (2003–07); 2009, Available at: http://www.riotintoironore.com/index.asp [accessed on May 15, 2009]. SAIL. BSP sustainability report 2004–2005. Steel Authority of India Limited (SAIL); 2009, http://www.sail.co.in/publication.php?tag=publications bspsustainability [accessed on July 15, 2009]. Schandl H, Poldy F, Turner GM, Measham TG, Walker DH, Eisenmenger N. Australia’s resource use trajectories. J Ind Ecol 2008;12(5/6):669–85. Sorme L. Inflow and accumulation of heavy metals in Stockholm, Sweden. In: Kleijn R, Bringezu S, Fischer-Kowalski M, Palm V, editors. ConAccount workshop: ecologizing societal metabolism: designing scenarios for sustainable materials management. CML Report No. 148. Leiden, The Netherlands: Center of Environmental Science; 1998. Spatari S, Bertram M, Fuse K, Graedel TE, Rechberger H. The contemporary European copper cycle: 1 year stocks and flows. Ecol Econ 2002;42:27–42. Spatari S, Bertram M, Fuse K, Graedel TE, Shelov E. The contemporary European zinc cycle: 1-year stocks and flows. Resour Conserv Recycl 2003;39:137–60.

Steel Recycling Institute. North American steel industry: reducing energy consumption. Jim Woods Steel Recycling Institute; 2009, Available at: http://www.sustainable-steel.org/energy.html [accessed on July 15, 2009]. TATA Steel. Setting the sustainable standards-corporate sustainability reports. TATA Steel; 2009, Available at: http://www.tatasteel.com/corporatesustainability/ reports.asp#csr [accessed on July 15, 2009]. Tanzer M. The race for resources-continuing struggles over minerals and fuels. New York and London: Monthly Review Press; 1980. p. 285. The Mining Association of Canada. Greenhouse gas emissions and energy management progress report. The Mining Association of Canada—GHG emissions and energy management progress report; 2007, 5 pp. Thomas V, Spiro T. Emissions and exposures to metals: cadmium and lead. In: Socolow C, Berkhout F, Thomas V, editors. Industrial ecology and global change. Cambridge: Cambridge University Press; 1994. Tilton JE, Lagos G. Assessing the long-run availability of copper. Resour Policy 2007;32:19–23. UK Steel. UK steel key statistics 2008; 2008, Available at: http://www.eef.org.uk/NR/ rdonlyres/FAACF4A6-902B-44E6-BCB5-43AE7EB7A5C3/13743/UKSteelKey Stats2009.pdf [accessed on May 15, 2009]. US EPA. Extraction and beneficiation of ores and minerals. Technical resource document: iron, vol. 3. EPA 530-R-94-030, NTIS PB94-195203; 1994, 122 pp. USGS. Iron ore statistics and information. US Geological Survey Minerals Information, US Department of Interior; 2008, Available at: http://minerals.usgs.gov/ minerals/pubs/commodity/iron ore/ [accessed on December 15, 2008]. Van der Voet E, Guinee JB, Udo de Haes HA, editors. Heavy metals: a problem solved? Dordrecht, The Netherlands: Kluwer Academic Publishers; 2000. Wang T, Muller DB, Graedel TE. Forging the anthropogenic iron cycle. Environ Sci Technol 2007;41:5120–9. WCED. Our common future. Oxford, UK: World Commission on Environment and Development, Oxford University Press; 1987. Weiss NL, editor. SME mineral processing handbook, volumes 1 and 2. New York, NY: Society of Mining Engineers of the American Institute of Mining, Metallurgical and Petroleum Engineers Inc.; 1985. Wilshire B, Homer D, Cooke NL. Technological economic trends in the steel industries. In: Monogrpahs in materials technology. UK: Pineridge Press; 1983. p. 215–51. Worldsteel. Steel statistical yearbook 2007. IISI Committee on Economic StudiesBrussels, Worldsteel Association (Worldsteel); 2007, 104 pp. Worldsteel. Raw materials. World Steel Association; 2009a, Available at: http://www.worldsteel.org/?action=storypages&id=221 [accessed on May 15, 2009]. Worldsteel. Steel and energy-fact sheet energy. World Steel Association; 2009b, Available at: http://www.worldsteel.org/pictures/programfiles/Fact%20 sheet Energy.pdf [accessed on May 15, 2009]. Worrell E, Price L, Martin N, Farla J, Schaeffer R. Energy intensity in the iron and steel industry: a comparison of physical economic indicators. Energy Policy 1997;25(7–9):727–44. Xueyi G, Yu S. Substance flow analysis of copper in China. Resour Conserv Recycl 2008;52:874–82. Yaksic A, Tilton JE. Using the cumulative availability curve to assess the threat of mineral depletion: The case of lithium. Resources Policy 2009;34: 185–94. Zeltner C, Bader HP, Scheidegger R, Baccini P. Sustainable metal management exemplified by copper in the USA. Reg Environ Change 1999;1:31–46.