Rare earths have been widely discussed in the popular press and at conferences because of their strategic importance, especially in clean energy technologies, but a reliable source of information that can raise the level of debates has been missing. This book fills the void. By a careful selection of topics, it meets its stated objective of describing the state of the art as of early 2014 on rare-earths occurrence, extraction, atomic structure, technology, applications, use, and recycling.
The first two chapters give an overview of the importance of rare earths, and data on production, use, and price, as well as volatility. Ores containing bastnäsite, monazite, and xenotime minerals and cation adsorption clays are industrially important. The ways these are processed to obtain usable forms such as oxides and metals are described in chapters 3–7. A special feature is the number of flow sheets and photographs the authors have thoughtfully provided in addition to equations.
The electronic structure of rare earths is an important topic (covered in chapter 8), and the 4f electron configuration determines their properties, including magnetic and optical behavior, as explained subsequently. Chapters 9–17 discuss applications in catalysis (ceria with platinum group metals), batteries (lanthanum, cerium, praseodymium, neodymium-nickel in cathodes), alloys (e.g., cast iron, magnesium), magnets (iron-neodymium-boron and samarium-cobalt), glass polishing (ceria), luminescent materials in fluorescent lamps (lanthanum, yttrium, cerium, europium, and terbium), optical-fiber amplifiers (erbium) and medical sensors (gadolinium, cerium, lutetium, and terbium), and lasers (ytterbium and neodymium). In each case, the underlying principles are discussed. The recycling techniques developed for materials used as above are discussed next. The concluding chapter 19 predicts an unstable situation until 2020, with one country dominating production, but holds out hope for new mines and substitutions for rare earths so that we are less dependent on them. The substitutes are often less green. An exception is the light-emitting diode, which has higher energy efficiency and is a replacement for fluorescent lighting containing rare-earth phosphors.
Each chapter starts with a list of objectives and ends with a summary. The book is well illustrated with 6–18 figures per chapter and has a 10-page section containing color photographs. The references (49) and suggested readings (50) are current up to 2014 and adequate, but not extensive, considering the information explosion in this topic. The book is recommended for graduate students with a background in condensed-matter physics, chemistry, and metallurgy; scientists; researchers in materials industries; and the wider audience interested in strategic materials.
China gave up the quota system this year and the hybrid electric car—the poster boy of rare earths—uses less of them in its recent versions. However, efforts to develop new sources, more efficient processes, recycling technologies, and substitutes are not expected to slow down. The outcome of these efforts will hopefully be covered in future editions. This readable book takes you through mines, extraction plants, research labs, pilot plants, factories, and recycling plants, on four continents. Enjoy the journey!
Reviewer: N. Balasubramanianis an independent research scholar working in Bangalore, India.
