Metal Sustainability

Global Challenges, Consequences, and Prospects

Reed M. Izatt, Reed M. Izatt

• Publisher: Wiley
• Year: 2016
• ISBN:
  9781119009122
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Chemistry
• Index: Chemistry

The sustainable use of natural resources is an important global challenge, and improved metal sustainability is a crucial goal for the 21st century in order to conserve the supply of critical metals and mitigate the environmental and health issues resulting from unrecovered metals.

Metal Sustainability: Global Challenges, Consequences and Prospects discusses important topics and challenges associated with sustainability in metal life cycles, from mining ore to beneficiation processes, to product manufacture, to recovery from end-of-life materials, to environmental and health concerns resulting from generated waste. The broad perspective presented highlights the global interdependence of the many stages of metal life cycles. Economic issues are emphasized and relevant environmental, health, political, industrial and societal issues are discussed. The importance of applying green chemistry principles to metal sustainability is emphasized.

Topics covered include:
•Recycling and sustainable utilization of precious and specialty metals
•Formal and informal recycling from electronic and other high-tech wastes
•Global management of electronic wastes
•Metal reuse and recycling in developing countries
•Effects of toxic and other metal releases on the environment and human health
•Effect on bacteria of toxic metal release
•Selective recovery of platinum group metals and rare earth metals
•Metal sustainability from a manufacturing perspective
•Economic perspectives on sustainability, mineral development, and metal life cycles
•Closing the Loop – Minerals Industry Issues

The aim of this book is to improve awareness of the increasingly important role metals play in our high-tech society, the need to conserve our metal supply throughout the metal life cycle, the importance of improved metal recycling, and the effects that unhindered metal loss can have on the environment and on human health.

1
Recycling and Sustainable Utilization of Precious and Specialty Metals

Reed M. Izatt¹ and Christian Hagelüken²

¹ Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah, 84602, U.S.A.

² Umicore AG & Co., KG, Hanau‐Wolfgang, Germany

1.1 Introduction

The need for increased and more effective recycling of our technology metal supply is urgent. This supply consists of both precious and specialty metals. Both sets of metals are essential to functioning of our high‐technology products, but for economic reasons there is much more interest in recycling the former than the latter. Average recycling rates for precious metals are above 50% [1], but huge differences exist depending on their application. For example, from chemical and oil refining process catalysts used in “closed cycles” over 90% of the precious metals contained therein are recovered even in case of long lifecycles of over 10 years. Closed cycles prevail in industrial processes where precious metals are used to enable the manufacture of products or intermediates. Hence, a closed cycle is typically taking place in a business‐to‐business (B2B) environment with no private consumers involved in its different steps. In such systems, the user of the metal‐containing product (e.g., the chemical plant) returns the spent product directly to a refiner who recovers the metals and returns them to the owner for a new product cycle. In most cases, the metals remain the property of the user for the entire cycle and the metal‐refiner conducts recycling as a service (so called toll refining). Third parties are hardly involved, and, if so, only as other‐service contractors (e.g., burning off carbon‐contaminated oil refining catalysts), but not taking property of the material. With such a setup, the whole cycle flow becomes very transparent and professionally managed by industrial stakeholders, resulting in very small metal losses.

Recycling rates are usually much lower in “open cycles” taking place in a business‐to‐consumers (B2C) environment. Typical examples are electronics and car catalysts. The owner of the spent product (e.g., an ELV or a PC), who might be number x in line after a number of preceding (second‐hand) product owners, does not return the product directly to a metals refiner. Instead, the product goes through a usually, long, complex and sometimes opaque chain of collectors and scrap dealers until it reaches the real metal recyclers, in a consolidated way. In this process, ownership of the metal changes each time a transaction occurs, transparency is low, business transactions can be rather strange and special, and resulting metal losses are usually much higher than in B2B closed‐loop systems. Important impact factors that determine the overall recycling rates of open cycles are intrinsic value, the ease or difficulty of accessing the relevant component or product, and legal or other boundary conditions that can help channel consumer products into appropriate recycling processes along the chain. An example on the high side (>95% recycling rate) is jewelry, where the high metal and emotional value of a gold ring, for example, prevents losses. Recovery rates of platinum group metals (PGM) can be 60 − 70%, in the case of automotive catalysts [2], which are quite successfully recycled (easy to disassemble from a car and high intrinsic value). However, metallurgical recovery rates for PGM are > 95% with the gap being due to exports of end‐of‐life (EoL) cars and long and opaque chains before a spent catalyst reaches a precious metals refinery. On the low side with average precious metal recycling rates below 15% are EoL electronic wastes (e‐wastes). This low recycling rate is caused by poor collection, often inappropriate pre‐treatment, and a high share of precious metal‐containing fractions that enter sub‐standard or informal recycling processes. Such processes operate with untrained personnel using crude equipment and result in severe adverse environmental and health effects [3]. Recovery rates of precious metals from e‐wastes, if treated in state‐of‐the‐art integrated smelter operations, would be > 95%, but the waste materials need to get there. The concept of open versus closed cycles has been described [4]. Summarizing, in open cycles metal losses are significantly higher than those that would be found in metallurgical refining. The net effect is that highly efficient state‐of‐the‐art technology [2] is used for only a small portion of waste products containing these precious and specialty metals. Products that are recycled properly are mainly those of high economic value and/or those from closed industrial loops. Recycling of specialty metals from such products is even more challenging. Metals in these products face the same limits of open cycles, but in addition with a lower economic value their recovery is far less attractive, and in some cases there are also thermodynamic limits. As has been elaborated [2,3,5] and is discussed later in this chapter, advanced metallurgical processes can co‐recover a number of specialty metals if they fit chemically into a specific extraction system, e.g., in addition to the precious metals, Se, Te, Sb, Sn and In, partially, can be extracted pyrometallurgically by the collector metals Cu, Pb or Ni. However, others like Ta, Ga, and rare earth metals do not extract well. This situation leads overall to very low recycling rates for many specialty metals. Although of high strategic importance in our society, many specialty metals are not recycled but are usually discarded to the commons after one, often brief, use.

The subject of recycling is central to the thrust of this book. Most chapters have sections dealing with the status of metal recycling. For example, Ueda et al. [6] describe Pt metal recovery at Tanaka Kikinzoku Kogyo K.K. in Japan. From these accounts, one can obtain an appreciation for the successes, inadequacies, and challenges associated with metal recycling throughout the world. The amount of e‐waste generated globally is enormous, estimated by several chapter authors as being 30 − 50 million tons yearly [7,8] with an estimated growth rate of 4 − 5% [8]. These numbers are startling and provide evidence for why it is incumbent on involved stakeholders to find technical and practical ways to improve global recycling processes [9,10]. However, it needs to be understood that only a fraction of this global waste is relevant for the recycling of precious and specialty metals. This fraction comprises of EoL information and communications technology (ICT) devices encompassing cellular phones, computer and network hardware, etc., and of audio‐video devices (radio, television, etc.). White goods as well as electric household devices such as vacuum cleaners, toasters or electric tools are of importance for the recycling of steel, base metals (e.g., Cu) and plastics but contain very small amounts of precious and specialty metals. In addition, especially for electronic devices, miniaturization and new types of products lead to a reduction of weight although sales numbers are still on the rise. Examples are TVs (CRT‐TV > 30 kg; LCD‐TV ≈ 16 kg, LED‐TV ≈ 14 kg) and computers (desktop PC ≈ 12 kg, notebook 2 − 3 kg, tablet 0.3 kg) [11]. Continuing on the current course has dire consequences for Earth’s metal supply as well as negative consequences for the global environment and health of Earth's inhabitants, human and otherwise [3].

Recycling of metals from modern high‐technology products, including waste electronics, EoL vehicles, and automotive catalytic devices is a complex procedure. Current recycling procedures from collection of EoL products to disassembling them into component parts to recovering target metals have been presented and discussed [9]. Important global benefits are derived from effective recycling, including the possibility of ‘mining’ target metals at a fraction of the economic and environmental costs associated with mining virgin ore [2,3]. However, there is a fundamental difference between a geological and an urban mine deposit. In general, a geological deposit is characterized by the composition and grade of its ore and by the total volume of the ore body leading to an estimation of the tonnage of target metals to be extracted. In a mining deposit, the ore body is concentrated in a specific location. It might be difficult to access and to mine the ore, but it exists in a defined space and it stays there. Hence, if total ore volume and metal prices justify, the necessary infrastructure will be built up and mining will start. The high investments and capital costs of operating a mine, consequently, force many operators to keep the mine running even at depressed prices as long as at least the variable operating costs can be covered.

In these respects, the challenge for secondary deposits, such as are found in an urban mine, is much greater. Although the “ore grade” might be significantly higher than in natural deposits, the urban mining activities are scattered over a vast area. In the case of consumer products, this area comprises millions of individual households. To make a real urban mine, it is first necessary to bring or pull the millions of devices — think about mobile phones or computers — towards the recycling facilities. Once there is a big pile of EoL devices at the gate of a recycling facility, it forms a real deposit, but not before. High metal prices and metal content in an EoL device (i.e., a high intrinsic value) can push these devices towards recycling, as it is the case with jewellery scrap or catalysts. However, if the intrinsic value is not sufficiently attractive, then pull mechanisms like waste legislation or business models such as leasing or deposit systems will be needed to generate an economically viable urban mine. Also, other than in primary mines, the system is much more vulnerable to price fluctuations. Decreasing metal prices can immediately stop the push mechanism, as the logistical costs involved are mainly variable. So, metallurgical recycling operations down the chain, which usually have high capital costs to bear, might be “overnight” faced with decreasing feeds. Hence, in the urban mine not only can the logistics be more challenging than in primary mines, but the economic drivers and feedback effects are often more complex. This is the reason that societal and legislative frame conditions are crucial for harvesting the urban mine.

Of equal importance to the technical and economic aspects of recycling is the involvement of stakeholders in decisions and actions involving recycling and sustainable ut...

Table of contents

• Cover
• Title Page
• Table of Contents
• List of Contributors
• Preface
• Acknowledgments
• 1 Recycling and Sustainable Utilization of Precious and Specialty Metals
• 2 Global Metal Reuse, and Formal and Informal Recycling from Electronic and Other High-Tech Wastes
• 3 Global Management of Electronic Wastes: Challenges Facing Developing and Economy-in-Transition Countries
• 4 Dynamics of Metal Reuse and Recycling in Informal Sector in Developing Countries
• 5 Metal Sustainability from Global E-waste Management
• 6 E-waste Recycling in China: Status Quo in 2015
• 7 Metallurgical Recovery of Metals from Waste Electrical and Electronic Equipment (WEEE) in PRC
• 8 Metal Pollution and Metal Sustainability in China
• 9 Mercury Mining in China and its Environmental and Health Impacts
• 10 Effects of Non-essential Metal Releases on the Environment and Human Health
• 11 How Bacteria are Affected by Toxic Metal Release
• 12 Application of Molecular Recognition Technology to Green Chemistry: Analytical Determinations of Metals in Metallurgical, Environmental, Waste, and Radiochemical Samples
• 13 Ionic Liquids for Sustainable Production of Actinides and Lanthanides
• 14 Selective Recovery of Platinum Group Metals and Rare Earth Metals from Complex Matrices Using a Green Chemistry/Molecular Recognition Technology Approach
• 15 Refining and Recycling Technologies for Precious Metals
• 16 The Precious Metals Industry: Global Challenges, Responses, and Prospects
• 17 Metal Sustainability from a Manufacturing Perspective: Initiatives at ASARCO LLC Amarillo Copper Refinery
• 18 Sustainability Initiatives at ASARCO LLC: A Mining Company Perspective
• 19 Recycling and Dissipation of Metals: Distribution of Elements in the Metal, Slag, and Gas Phases During Metallurgical Processing
• 20 Economic Perspectives on Sustainability, Mineral Development, and Metal Life Cycles
• 21 Closing the Loop: Minerals Industry Issues
• Index
• End User License Agreement