Extractive metallurgy is that branch of metallurgy that deals with ores as raw material and metals as finished products. It is an ancient art that has been transformed into a modem science as a result of developments in chemistry and chemical engineering. The present volume is a collective work of a number of authors in which metals, their history', properties, extraction technology, and most important inorganic compounds and toxicology are systematically described.

Rare Earth Oxides are used in mature markets (such as catalysts, glassmaking and metallurgy), which account for 59% of the total worldwide consumption of rare earth elements, and in newer, high-growth markets (such as battery alloys, ceramics, and permanent magnets), which account for 41% of the total worldwide consumption of rare earth elements.

For the last twenty years conferences concerning rare earth materials have been held in the U.S.A. every 18 to 24 months. In general these conferences have dealt with the science of these materials, and only one or two sessions (~10% of the papers) were concerned with industrial and commercial aspects.

Rare earth elements are used in mature markets (such as catalysts, glassmaking, lighting, and metallurgy), which account for 59 percent of the total worldwide consumption of rare earth elements, and in newer, high-growth markets (such as battery alloys, ceramics, and permanent magnets), which account for 41 percent of the total worldwide consumption of rare earth elements.

The concentration of production of rare earth elements (REEs) outside the United States raises the important issue of supply vulnerability. REEs are used for new energy technologies and national security applications. Is the United States vulnerable to supply disruptions of REEs? Are these elements essential to U.S. national security and economic well-being?
There are 17 rare earth elements (REEs), 15 within the chemical group called lanthanides, plus yttrium and scandium. The lanthanides consist of the following: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Rare earths are moderately abundant in the earth’s crust, some even more abundant than copper, lead, gold, and platinum.

The term rare earths denotes the group of 17 chemically similar metallic elements that includes scandium, yttrium, and the lanthanides (Spedding 1978; Connelly et al. 2005). The lanthanides are the series of elements with atomic numbers 57 to 71, all of which, except promethium, occur in nature. The rare-earth elements, being chemically similar to one another, invariably occur together in minerals and behave as a single chemical entity. Thus, the discovery of the rare earths themselves occurred over a period of nearly 160 years, from 1787 to 1941 (Szabadvary 1988; Weeks 1956).

Geology, Geochemistry, and Natural Abundances of the Rare Earth Elements

Sustainability of Rare Earth Resources

The Electronic Structure of the Lanthanides

Variable Valency

Group Trends

Solvento Complexes of the Lanthanide Ions

Lanthanides in Living Systems

Lanthanides: Coordination Chemistry

Organometallic Chemistry Fundamental Properties

Lanthanides: ‘‘Comparison to 3d Metals’’

Luminescence

Lanthanides: Luminescence Applications

Magnetism

The Divalent State in Solid Rare Earth Metal Halides

Lanthanide Halides

Lanthanide Oxide/Hydroxide Complexes

Lanthanide Alkoxides

Rare Earth Siloxides

Thiolates, Selenolates, and Tellurolates

Carboxylate

Lanthanide Complexes with Amino Acids

β-Diketonate

Rare Earth Borides, Carbides and Nitrides

Lanthanide Complexes with Multidentate Ligands

Alkyl

Aryls

Trivalent Chemistry: Cyclopentadienyl

Tetravalent Chemistry: Inorganic

Tetravalent Chemistry: Organometallic

Molecular Magnetic Materials

Near-Infrared Materials

Superconducting Materials

Metal–Organic Frameworks

Upconversion Nanoparticles for Bioimaging Applications

Oxide and Sulfide Nanomaterials

Rare Earth Metal Cluster Complexes

Organic Synthesis

Homogeneous Catalysis

Heterogeneous Catalysis

Supramolecular Chemistry: from Sensors and Imaging Agents to Functional Mononuclear and Polynuclear Self-Assembly Lanthanide Complexes

Endohedral Fullerenes

Lanthanide Shift Reagents

Lanthanides: Magnetic Resonance Imaging

Luminescent Bioprobes

Sensors for Lanthanides and Actinides

Data on rare earth (including yttrium) mines, deposits, and occurrences were compiled as part of an effort by the USGS and the University of Arizona Center for Mineral Resources to summarize current knowledge on the supply and demand outlook and related topics for this group of elements. Economic competition and environmental concerns are increasingly constraining the mining and processing of rare earths from the Mountain Pass mine in California. For many years, the deposit at Mountain Pass was the world's dominant source of rare earth elements and the United States was essentially self-sufficient. Starting approximately 10 years ago, the U.S. has become increasingly dependent (> 90 percent of separated rare earths) upon imports from China, now the dominant source of rare earths. Knowledge of the known economic and noneconomic sources of rare earths is basic to evaluating the outlook  for rare earth upply and associated issues. <...>

The problem of application of geochemical methods in prospecting for metals has become progressively more urgent in recent years. Credit ought to be given to our geophysicists, who were the first to raise this problem and also the first to undertake its solution.

In 1949 a large bastn8site deposit was discovered at Mountain Pass, Cal if. Subsequent development of the deposit made the Uni ted States the worl d's largest source of rare-earth minerals. Since 1965, bastnisi te, a f luocarbonate of the cerium-group metals, REFC03, has replaced monazite as the principal source of rare earths; in 1978 it accounted for more than ha l f of the world production (§_).3 Rare-earth a lloys and compounds are used in petroleum crac.kin.g catalysts, ductile iron and high-strength, lo..,..alloy (HSLA) steel production, high- energy pertn4lnent magnets, color tel evi si on pi cture tubes, glass polishing and decolorizing, and ceramics. <...>