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Bureau of Mines / Minerals yearbook: Metals and minerals 1978-79
Year 1978-79, Volume 1 (1978-1979)

Moore, Christine M.
Rare-earth minerals and metals,   pp. 735-742 PDF (915.0 KB)


Page 741

Country1 
 1976 1977 l978P 1979e 
Australia                                                
Brazil                                                   
Indiae                                                  
Korea,Republicof"                                         
Malaysia2                                                
Nigeriae                                                 
SriLanka                                                
Thailand                                                
r5853 
1,775 
3,300 
 10 
2,071 
 20 
 1 
9,377 
2,691 
3,014 
10 
2,179 
20 
e~ 
14,864 e2700 
3,607 
10 
1,392 
20 
220 
845 
17,000 
2,700 
3,100 
10 
2,200 
220 
800 
United States                                                
W 
W 
W 
W 
Zaire                                                   
265 
106 
85 
85 
 RARE-EARTH MINERALS AND METALS 741 
Table 4.—Monazite concentrates: World production, by country 
(Short tons) 
 Total r13,295 17,402 23,743 26,115 
 e5~timate. "Preliminary. ~ W Withheld to avoid disclosing company proprietary
data. 
 ' In addition to the countries listed, Indonesia and North Korea may produce
monazite, but output, if any, is not reported quantitatively, and available
general information is inadequate for formulation of reliable estimates of
output levels. 
2Exports. 
TECHNOLOGY 
 General Motors investigated a new method of fabricating thin curved rare-earth
cobalt magnets.4 The process involves two steps to compact rare-earth cobalt
powder to precise final shape, including a means of gently restraining the
pressed part to allow it to shrink during sintering to its final density
of 96% of its theoretical density. The process would reportedly lower inanufacturing
costs by eliminating the need for diamond grinding, and reducing material
waste and the potential for magnetic breakage. The magnet used in the investigation
was made of 75% samarium and 25% mischmetal in a 1:5 rare-earth to cobalt
ratio. 
 A chemical engine using a lanthanumnickel alloy powder was investigated
to recycle heat from low-temperature industrial process fluids and gases.5
When the powder is heated, the lanthanum-nickel emits hydrogen at sufficient
pressure to operate a piston in a cylinder. The new development enables the
use of heat of less than 100'C. 
 The U.S. National Aeronautics and Space Administration elected to study
processing of neodymium~~-doped laser glass as one of the 14 programs in
its materials-processing programs aboard the space shuttle transport.6 The
anticipated suppression of crystallization by containerless processing could
be used to extend the glass-forming region, which presumably would result
in the ability to produce a laser glass with an enhanced lasing-line cross
section. 
 An alternative to purification of gadolinium metal by distillation was investigated.7
The study involved the evaluation 
of LiF-GdF3 and LiF-BaF2-GdF3 as electrnlytes for electrorefining gadolinium.
The effects of electrolyte composition and purity, temperature, and current
density on the purity of the final product were studied. 
 A review of fused-salt electrowinning of individual rare-earth metals-yttrium
metal, and mischmetal-from their respective chlorides and oxides was published.
The article included a review of preparation of alloys of yttrium and rare-earth
metals by fused-salt electrolysis and electrorefining of yttrium metal.8
 The effects of rare earths on the structure and properties of cast irons
were reviewed.~ 
 Silicon nitride for high-temperature engineering applications was studied
by several groups. Two studies reported using yttria as an additive to improve
high-temperature properties of silicon nitride.1° The effects of
impurties
(Al, Fe, and Ca) in hot-pressing of yttria-doped silicon nitride were discussed."
The densification and phase transformation behavior of yttria-doped silicon
nitride were studied by comparing its behavior with that of magnesium oxide
(MgO)-doped and lithiadoped silicon nitride.'2 
 A report on current research concerning rare earths in the U.S.S.R. was
published.'~ Included in the report were industrial and military uses of
rare earths as well as descriptions of ongoing research for the use of rare
earths in laser systems, electronic applications, magnetohydrodynamic power
generation, refractory applications, and catalysts. 
 Researchers at Oak Ridge National Laboratory developed a cyclic process
using ceric oxide to generate hydrogen from water or 


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