The SQUID-based system uses radios that are hand-held which would greatly reduce the cost of "hard wiring" communications systems in remote areas. The new system would provide miners with a means to remain in voice contact during emergency situations. Existing narrow-band FM radios operate at higher frequencies, requiring the operator to remain within a short distance from the underground electrical conductor. Not only would the SQUID system allow greater movement of a miner, but it operates at a lower frequency, penetrating rock and offering increased sensitivity over existing underground radio systems. The communication system may also allow increased communication through water as well as aid in enhanced mineral exploration.

The experimental SQUID setup incorporates a 3 inch diameter, 8 inch long dewar with a 26 hour liquid nitrogen hold time. The commercial application would include a 2 inch diameter dewar which would provide a 12-16 hour hold time, longer than a miner’s work shift. The test device had a galvanicly coupled design that had a noise floor of 400 femtotesla per root Hz in the laboratory. It was designed to minimize flux trapping without regard for sensitivity.

In addition to preventing fracture in the Y₂O₃-doped ZrO₂ (YSZ) ceramic material, the 0.0025 mm-thick titanium layer also reduces friction. Besides titanium and titanium alloys, other coating materials include gold, silver, platinum, and tantalum. The layer must exhibit strong adherence to the YSZ ceramic, malleability, and galvanic compatibility with common trunnion materials such as cobalt-chromium and titanium alloys. This new development will also allow construction of smaller diameter hip heads that further reduce friction and the associated wear debris.

Ytterbium metal demonstrates a gradual valence transition from 4f¹⁴(spd)² to 4f¹³(spd)³ (divalent to trivalent) at pressures up to 30 GPa. The researchers wanted to establish a clear correlation between the high pressure valence transition of Yb, from 2⁺ to 3⁺, with an increase in pressure so as to be able to identify it with the other rare earth metals. To do this, Yb metal foil was loaded onto a 65 m m diameter anvil cell along with copper powder. The sample was subjected to pressures up to 202 GPa in which the Yb metal shows a sequence of phase transformations from fcc(I) ® bcc ® hcp ® fcc(II) ® hP3 with increasing pressure.

Ytterbium metal exhibits increasing compressibility until the maximum, V/V₀=0.26, is reached at 202 GPa. The unusual compressibility (76%) of Yb at 202 GPa is attributed to interconfiguration valence fluctuations (4f¹⁴ ® 4f¹³) and s ® d electronic arrangements in the compressed state.

The importance of identifying Ca²⁺ in living systems is that it is an important intracellular secondary messenger of signal transduction. Changes in Ca²⁺ concentration trigger changes in cellular metabolism and are responsible for cell growth and regulation.

To be used as a MRI contrast agent, the Gd³⁺ ion in aqueous solution must be chelated to a ligand in order to reduce toxicity. Typically, eight of the nine available Gd³⁺ coordination sites are bound by the chelate, leaving one site available for an inner sphere water molecule. This is the mechanism by which the new MRI agent modulates access of water to a Gd³⁺ ion in the presence or absence of Ca²⁺.

The Gd complex was prepared in an 8-step process from monoalkylated nitroresorcinol, including dimerization, the conversion of free hydroxyls to dibromides, and following up with alkylation in a base while hydrolyzed aromatic imino ethyl diacetates. The result was a final Gd³⁺ complex that was formed in good yield and under weakly acidic conditions.

A new optical fiber sensor that utilizes the Tm³⁺ ion has been shown to have promise in recording a wide range of temperatures, from 350° C to 1250° C. Intrinsic fluorescence-based Tm-doped fiber optic materials are simple and relatively robust. The Tm³⁺ ion at a concentration of ~280 ppm was doped in a SiO₂ fiber that had a numerical aperture of 0.2. The core diameter was ~15 m m and had a cladding diameter of ~125 m m. The doping level of 280 ppm is similar to that of the lowest value of doping in Er fibers (200 ppm). The lower doping levels and related absorption are associated with a pure exponential decay of the fluorescence emission.

The Tm-doped fiber showed strong optical absorption coefficients on the 690, 800, and 1200 nm wavelength bands. Fluorescence emission was exhibited at the central wavelengths of 1.46, 1.9, and 2.3 m m simultaneously. The lifetime of the Tm³⁺ fluorescence emission at 1.9 m m was measured to be shorter than 200 m s. The sample was heat treated at 1100° C for ~12 hours, and then 1250° C for ~19 hours, and was shown to have no degradation of the fluorescence lifetime. As a comparison, Er-doped fibers degrade at 1100° C and Nd-doped fibers at 750° C. However, there was significant and distinct lifetime ranges of ~63 m s at 100° C to ~15 m s at 1250° C which identify the material as a promising temperature probe.

When the nerve agent sarin and soman hydrolyze in water, the result is a product with a distinct molecular imprint that can be detected in trace amounts by an optical fiber that is treated with Europium {Anal. Chem., 71, [2] 373-8 (1999)}. The fiber is hooked to a spectrometer and a light source. Light is directed to the end of the fiber in the sample being tested and the luminescence that returns from the tip is analyzed by the spectrometer. The benchtop version of the sensor is able to detect sarin and soman in water at concentrations as low as 660 parts per quadrillion (660 parts in 1 x 10¹⁵).

The 277-page hard cover journal contains eight chapters: Metamagnetic Behavior, Exotic Superconductors, Kondo Insulators, Low-Density Carriers, Non-Fermi Liquids, Quadrupole and Charge Orderings, Electronic State of f -Electronic Compounds, and Miscellaneous Problems of f -Electron Compounds. Included is the reported physical, magnetic, electrical, thermal, transport, and other properties of CeRu₂Si₂, Ce_xCu₂Si₂, CeCu₆, CeRu₂, CeNiSn, YbB₁₂, Yb₄As₃, GdAs, rare earth binary chalcogenides and pnictides, ternary borides, Yb-Au compounds, among others.

The hard-cover book includes 9 chapters and 314 pages. Chapter 1 "Thermodynamics of Rare earth Elements in Iron Metals" introduces the thermodynamic data of rare earth elements in liquid iron, determined by anhydrous electrolysis at low temperature by radioisotope assay. Chapter 2 "Thermodynamics of Alkaline Earth Elements and Bismuth in Liquid Iron, Nickel and Manganese" contains some limited information on the reaction of rare earth oxysulfides with hydrogen in sulfur extraction. The third chapter "State of Existence and Microdistribution of Rare Earth Elements in Steel, Cast Iron, Aluminum and Aluminum Alloy" includes information on chemical stability of rare earths in electrolytes. The next two chapters "Inclusions in Steel, Reaction of Rare Earth with refractory and Nozzle Blockage" and "Application of Rare Earth Metals in Steel" covers some uses of rare earths in steel making (including stainless steel) and some insights into the effects of rare earths in the physical properties of various compositions. Chapter 8 "Calculation of Thermodynamic Parameters by Solution Models" deals with the evaluation of interaction parameters in ternary alloys, among others, and the final chapter "Diffusion in Melts and Metals" includes a few pages on the diffusion of cerium in slag.

Permanent-Magnet Materials and their Applications contains 8 sections. Section one is a brief introduction to the review and covers a short history of rare earth-based magnets. The second section "Basic Concepts and Models" deals with magnetic coupling and magnetocrystalline anisotropy, followed by the main section of the book "Rare Earth Based Permanent Magnet Materials" which contains information on Nd₂Fe₁₄B materials, including physical properties and phase relationships, manufacturing routes and later developments in Nd-Fe-B sintered, hot-formed, and bonded permanent magnets, a mention of the ternary carbides with the Nd₂Fe₁₄B structure. Also included in the section are SmCo₅ and Sm₂Co₁₇ type magnets, ternary iron-rich RFe_12-xM_x, interstitially modified R₂Fe₁₇ and R₃(Fe,M)₂₉ compounds, and nanocrystalline rare earth based permanent magnet alloys. The next four sections contain information on 3d-transition metal alloy magnets, miscellaneous magnet materials, hard ferrites, and applications of permanent magnets.

The 82-page Permanent-Magnet Materials and Their Applications was published in soft cover in 1998 and contains a complete listing of the 224 references used in the review. It is recommended for students studying these materials, or anyone interested in rare earth permanent magnets, and is essential reading for anyone who needs a quick background in the field.

Of the minerals used in international trade and commerce, there are three that are of interest to rare earthers: Rare Earths, Scandium, and Yttrium. The rare earths section contains, in two pages, domestic production and use, U.S. salient statistics, recycling, import sources, tariffs, depletion allowances, events, trends, and issues, world mine production, reserves, and reserve base, world resources, and apparent substitutes. The Scandium and Yttrium sections contain information on the same topics, but with the appropriate concentration of information for these two elements in a snapshot.

The minerals present at the deposit include rare earths and are located in several vein-like dikes (quartz albite vein-dikes and pegmatite dikes) which extend outward from the main granitic intrusion {Int. Calif. Mining Journal, January, 44-46 (1999)}. The dikes have been analyzed and indicate a resource of 6.8 million tons of ore at a yield of 0.264% rare earth oxide, of which about one third is yttrium. The dikes also include zirconium oxide and niobium oxide. It is possible that there may be more rare earth-bearing dikes at Bokan Mountain that have yet to be discovered.

Recovery of Bokan Mountain rare earths have been tested by sulfating the ore at 250° C for 1 hour at a H₂SO₄ to ore ratio of 1:1, and water leaching the sulfated material at 25° C which dissolves over 74% of the Yttrium, Cerium, and Lanthanum in the ore. Traditional solvent extraction techniques yield 96% Yttrium from the solution.

Additional information on the Bokan Mountain rare earth deposit is contained in U.S. Bureau of Mines Open-File Report 33-89, published in 1989. To order, contact the U.S. Geological Survey Library, 345 Middlefield Road, MS 955, Menlo Park, CA 94025-3591 USA; Tel: 650 329 5027/5026; Fax: 650 329 5094; mailto:men_lib@usgs.gov; www.usgs.gov/library/menlib.html.

Since the mine is located some distance from the secondary processing facility and the export facilities at Freemantle, considerable efficiency must be employed in order to make the operation profitable. In fact, since 1994, several improvements in rare earth processing, along with other developments in Australia and with other rare earth producers, are allowing Mt. Weld to once again be a factor in the field of rare earths. The improved prospects include: improved monazite concentration, established chemical/powder infrastructure in the nearby North Eastern Goldfields, increased demand and prices for rare earth products, an extension of the Project Environmental Approval to mid-2001, and the dewatering step of the carbonatite, which will reduce mine development costs.

A drilling program to collect a representative sample of the mineralization was completed in March and the samples were bench-tested for improved ore beneficiation techniques. As a result of the test, it was determined that high-grade monazite concentrate can then be upgraded to high value rare earth products when transported to a secondary processing plant located at the Meenaar Industrial Park, near Northham, Western Australia, some 760 km west of Mt. Weld. If the plan progresses on schedule, then construction of the mine and processing plant would commence in 2001 with the aim of complete operations beginning in late 2002.

The minimum cost to receive the results of a computer search is US$50.00 (for 25 citations and US$2.00 for each citation over 25 per search). However, many organizations become supporters which allows them to not only receive as many searches as needed for one year, but as an added benefit, they receive the monthly two-page newsletter RIC Insight. RIC Insight provides a provocative view into recent developments of rare earth science and technology and how these may impact the rare earth industry. The cost to become a supporter is US$100.00 for an individual, or US$300.00 for a corporate membership.

Send requests to: Rare-earth Information Center, 112 Wilhelm Hall, Iowa State University, Ames, IA 50011-3020 USA; Tel: 515 294 5405; Fax: 515 294 3709; ric@ameslab.gov.

A new nickel-based yttrium-containing alloy, claimed to be the first formable material that contains 8% tantalum, has been developed by Krupp VDM GmbH, Werdohl, Germany {Adv. Mater. Proc., 155, [2], 9 (1999)}. In addition to Ni and Ta, the new alloy contains 25% chromium, 3% aluminum, 0.3% carbon, 0.1% Yttrium and is designated Nicotan 6325hAlC-alloy 2100 GT. It was specifically designed for high-temperature applications in combustion chambers, heat shields and thrust reversers for gas turbines.

For more information contact Don Wenschof, Krupp VDM Technologies Corporation Corp., 10 Sylvan Way, Parsippany, NJ 07054 USA; Tel: 973 267 8545; Fax: 973 292 4919; don@vdmt.com.

TDK Corporation has reportedly doubled its production capacity of NdFeB permanent magnets at its Narita plant in Chiba Prefecture, Japan {The Kagaku Kogyo Nippo, April 28, 1999}. The expansion is expected to meet future demand of voice coil motors, and magnetic rollers used in printers. The company plans to increase production of NdFeB by 50% to 130 tons per month by July of this year, and to 200 tons per month by next spring.

We receive referral requests from interested clients from time to time about consultants in the rare earth field. Several years ago we kept a list but it now needs updating. If you would like us to refer prospective customers to you for consulting services, just send us the following information:

This listing is provided at no cost as part of the RIC’s service to the worldwide rare earth community. The information should be sent to: LaVonne Treadway, 116 Wilhelm Hall, Iowa State University, Ames, IA 50011-3020 USA; Tel: 515 294 2272; Fax: 515 294 3709; RIC@ameslab.gov.

To appear in our Consultant’s Corner, any individual, company, or group must be involved in rare earth or rare earth-related consulting activities. Just send us the appropriate information: contact name, company name, mailing address, Tel/Fax number(s), e-mail and web address, and areas of expertise.

The symposium Rare Earths and Actinides: Science, Technology, and Applications IV will be held during the 2000 TMS Annual Meeting in Nashville, Tennessee, USA. The symposium is scheduled during the spring meeting March 12-16, 2000. The symposium will provide a venue for presenting the developments and current state of the art in the science, technology, and applications of rare earths and actinides for the next century. Topics to be covered include resources, markets, extraction, processing, purification, precipitation, electrolysis, physics and chemistry in the preparation of magnets, electronic materials, batteries, alloys, films, etc., and modeling the processes in the preparation and manufacture of products that contain rare earths and actinides.

For more information, contact Renato G. Bautista, Department of Chemical and Metallurgical Engineering, University of Nevada-Reno, Reno, NV 89557-0136 USA; Tel: 775 784 1602; Fax: 775 784 4764; bautista@quake.seismo.unr.edu

Letter to the Editor

Dr. J. Schijf, senior chemist
Department of Marine Science
University of South Florida
140 7^th Avenue S
St. Petersburg, Florida 33701-5016 USA
jschijf@seas.marine.usf.edu
Tel: 727 553 3936; Fax: 813 553 1189

Johan Schijf

Patron ($1000 to $1999)
Mitsubishi Materials Corp., Japan (15)
R.E.M. s.a., Belgium (6)

Sustaining ($400 to $999)
Auer-Remy GmbH, Germany (12)
BOSE Corp., USA (22)
Daiden Co., Ltd., Japan (7)
Hydro Research Centre, Norway (27)
Johnson Matthey-Rare Earth Products, UK (25)
Mitsui & Co. (U.S.A.), Inc., USA (14)
Pacific Industrial Development Corp., Inc., USA (7)
Research Institute of Industrial Science & Technology (8)
Ushio Inc., Harima Plant, Japan (10)

Contributor (less than $400)
APL Engineered Materials, Inc., USA (13)
Atomergic Chemetals Corp., USA (27)
Ervin Product Development Center, USA (2)
General Atomics, USA (1)
Helsinki University of Technology, Finland (1)
Hicks Dome Corp., USA (13)
HJD Intnl, USA (11)
Palm Commodities International, Inc., USA (5)
Prochem, Inc., USA (6)
RFT S.p.A., Italy (2)
Sumitomo Special Metals America, Inc., USA (14)
Swedish Institute for Metals Research, Sweden (2)
Walker Magnetics Group, Inc., USA (11)

Individual
Peter Campbell, USA (8)
Bhanu Chelluri, USA (2)
Robert L. Dotson, USA (1)
Luis Fabietti, Argentina (1)
Norton Jackson, Australia (6)
Hugh D. Olmstead, USA (6)