A comprehensive review is presented of the extractive metallurgy of rare earths. The topics covered are: world rare earth resources and production; ore processing and separation of individual rare earths; reduction, refining, and ultrapurification of rare earth elements; methods for rare earth materials analysis; and a selection of the numerous rare earth applications. World rare earth reserves are abundant and would last for well beyond the next century. However, all of the 16 naturally occurring rare earth elements are not equally distributed in the ore minerals. This, compounded with the problems specific to the isolation and recovery of each of the rare earths, sets the stage for an unequal rare earth availability. The close chemical similarity of rare earths looses its importance when divergent physical properties determine the processes for rare earth element reduction and refining. The rare earth metals, alloys, and compounds have been as pure as could be determined. Finally, the commercial...

Extractive Metallurgy of Rare Earths

Water purification using magnetic assistance: a review.

Nanophase hard magnets

The tetragonal L10 family of ferromagnets including the Co-Pt, Fe-Pt, Fe-Pd and Mn-Al alloy systems exhibits high, uniaxial magnetocrystalline anisotropies with first anisotropy constants K1 ~ 107–108 ergs/cm3. The domain parameters of these materials are similar to the rare earth permanent magnets and the defect structure is dominated by planar faults such as APB's, stacking faults, and twins. In this study the micromagnetic analysis of Kronmuller has been applied to elucidate the mechanism of coercivity controlling the hysteresis of the polytwinned L10 FePd equiatomic alloy and the results are consistent with pinning control involving atomically thick, planar defects. Also, Lorentz microscopy has been used to observe the interaction of magnetic domain walls with the planar faults characteristic of these materials. Finally, a thermomechanical treatment involving concomitant ordering and recrystallization is shown to eliminate the well-known polytwinned structures which generally evolve during the formation of the L10 phase leading to enhanced coercivities. The fundamental structure-property relationships involved are discussed.

Magnetic hardening and coercivity mechanisms in L10 ordered FePd ferromagnets

Introduction to Magnetic Measurements Fundamentals of Magnetic Measurements Historical Background Main Terms The Magnetization Process of Ferromagnetic Materials Anisotropy and Texture Electromagnetic Loss Influence of the Magnetic Field on Physical Properties of a Material Magnetic Resonance Superconductivity Used in Magnetic Measurements Main Rules of Magnetics The Physical Principles of Magnetism The Magnetic Hysteresis Sources of a Magnetic Field The Samples and Circuits of the Material under Test Magnetic Shielding Magnetic Materials Soft Magnetic Materials: General Information Silicon Iron Electrical Steel Nickel- and Cobalt-Based Alloys Amorphous and Nanocrystalline Alloys Soft Ferrites Hard Magnetic Materials Special Magnetic Materials Magnetic Sensors General Remarks Induction Sensors Fluxgate Sensors Magnetoresistive and Magnetoimpedance Sensors Hall-Effect Sensors Resonance Sensors SQUID Sensors Resonance Sensors and Magnetometers Other Magnetic Sensors Testing of Magnetic Materials AC Testing of Soft Magnetic Materials DC Testing of Soft Magnetic Materials Testing of Hard Magnetic Materials Special Methods of Testing of Magnetic Materials Magnetic Field Measurements and Their Applications Environment Magnetic Fields Applications of Magnetic Field Measurements Magnetic Diagnostics Index References appear at the end of each chapter.

J.F. Herbst

Papers

Neodymium-iron-boron permanent magnets

Magnetic properties of Nd2(CoxFe1-x)14B alloys

On the formation of NdFe9.5−xTx compounds (T = Ti, Cr, Mn)

Crystal and magnetic structure of Ce2Fe14B and Lu2Fe14B

Renormalized atoms and the calculation of core electron excitation energies in the rare earths