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Bureau of Mines / Minerals yearbook: Metals, minerals, and fuels 1972
Year 1972, Volume 1 (1972)

Sondermayer, Roman V.
Thorium,   pp. 1201-1208 PDF (856.3 KB)

Page 1206

ings output of the concentrator is processed through the plant. About 22,000
tons per day of dry solids represents the average quantity fed to the plant.
Uranothorianite concentrate, obtained by gravity concentration and containing
approximately 5% U308, 14% Th02, and 65% Zr02, was processed through the
chemical extraction plant. Thorium and uranium are extracted by leaching
with hot nitric acid. The liquor containing thorium and uranium is then treated
in a solvent extraction circuit and the product calcined. A new feature of
the process is the provision of facilities for recovery of nitric acid and
thorium from the barren solution or raffinate from the solvent extraction.
Since the ThQ2:U308 ratio is 
on the order 2.5:1, thorium could become an important byproduct.8 
 United Kingdom.—The United Kingdom Atomic Energy Authority won a contract
to design and supply a solid moderator reactor (SMR) for the THTR under construction
at Schmehausen in West Germany. The function of the SMR is to facilitate
reloading of the THTR.~ 
 Venezuela.—The Government announced a discovery of thorium in the
Cerro Impacto Codesur area of southern Venezuela. The area was reserved for
exploration by the State through a Governmentowned corporation called Promocion
Del Desarrollo Del Sur de Venezuela (Prodesur). Information on size of deposits
and reserves was not reported. 
 Energy and metallurgical applications together with extraction techniques
were the principal subjects of studies related to thorium during 1972. Most
of the research was basic, and industrial utilization of results was not
 Nonenergy.—At the Elliot Lake uranium mine in Ontario, Canada, large
volumes çf waste materials contain thorium. An investigation was conducted
to find a solvent extraction process for the coextraction of uranium and
thorium. The new approach would. replace the present precipitation procedure
for thorium elimination, which is costly because of neutralization and coprecipitation
losses of the rare earths. Results indicated that high-purity thorium sulfate
can be produced with the ion exchange-neutralization route. In addition,
increased revenue would result if thorium is recovered.10 
 Metallurgical research was directed toward studies determining the effects
of thorium and thorium compounds on physical and chemical properties of alloys,
mostly high-temperature alloys, in different environments. One investigation
indicated that addition of Th02 to high-temperature nickel or cobalt-base
superalloys slows oxidation. In an oxidation process induced by Na2SO4, the
presence of ThO2 in a nickelchromium alloy promoted selective oxidation of
chromium, and the growth rate of the chromium oxide layer was approximately
one order of magnitude less than 
that ' for growth of chromium oxide in simple nickel chromium alloys.11 
 The application of fine wires as highstrength structural components requires
a better undertanding of differences of creep behavior. The creep properties
of fine, recrystallized tungsten-thorium oxide (1% ThO2 by weight) wires
were studied over the temperature range 1,800° to 2,750° C. The creep
behavior of tungsten-thorium alloy wire depends on grain structure, temperature,
and stress. The study showed that the creep behavior of fine wires was not
affected by geometry, and identical results could be expected for larger
diameter specimens.12 
 Ronson Metals Corp.'s "CerAlloy 400," made of approximately 80% thorium,
15 mischmetal, and 5% aluminum, was used in plutonium-powered pacemakers
(small devices, surgically implanted in body, regulating the rhythm of heart
beat). The new pacemaker should operate for 10 years 
 8 Ne!, V. Pa1abora~s New Heavy Minerals Plant 
Adds Uranium Concentrate to the Recovery List. 
Eng. and Mi J., v. 173, No. 11, November 
1972, pp. 186—187. 
 9 Chemistry and Industry. UKAEA Win Reactor Contract. No. 3, Feb. 5, 1972,
p. 104. 
 10 Ritcey, H. C., and B. H. Lukas. Co-extraction of Uranium and Thorium.
J. of Metals, v. 24, No. 4, April 1972, pp. 39—44. 
11 David, H. H., H. C. Graham, and G. F. 
Uhlig. Oxidation of Na2SOS-Coated Ni-2OCr- 
2ThO2. Met. Trans., v. 3, No. 12, December 
1972, pp. 3247—3257. 
 12 Moon, D. M. Creep of Fine Wires of ' NTh02 Alloys. Met. Trans., v. 3,
No. 12, December 1972, pp. 3097—3102. 

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