Page 553

  553Gallium 
By E. Chin 1 
 Domestic production of gallium in 1972 increased sharply over production
in the previous year. Most of the gallium consumption was for the production
of gallium in-term-etallic compounds used in 
light-emitting diodes for electronic visual display panels. Sales of gallium-arsenidephosphide
for optoelectroni'c devices were estimated at $;14.5 million in 1912, up
from $4 million in 1971. 
DOMESTIC PRODUCTION 
 Production of gallium metal in 1972 by two companies was more than double
that in 1971. The sharp rise in production was attributed to increased demand
for gallium by the electronics industry. 
 Gallium metal was produced as a byproduct of alumina production by the Aluminum
Company of America (Alcoa) at its Bauxite, Ark., plant. Gallium metal, oxide,
and trichloride were produced by Eagle-Picher Industries, Inc., at its Quapaw,
Okla., plant. Production data are company confidential. In addition, gallium
metal and compounds produced primarily from imported material were supplied
by Alusuisse Metals, Inc., Atomergic Chemetals Co., Cominco American, Inc.,
Euro- 
pean Electronics, Inc., B. Freudenberg, Inc., Indium Corporation of America,
Kawecki Berylco Industries, Inc., and Ventron Corp. Alcoa announced a breakthrough
in production technology which reportedly will enable the company to triple
its gallium production capacity at the Bauxite, Ark., plant. Additional gallium
production may be possible at Alcoa's refineries at Mobile, Ala., and Point
Comfort, Tex. 
 Canyon Land 21st Century Corp. (Canyon Land), Blan-ding, Utah, is expected
to begin production of gallium in late 1973. Canyon Land will use as its
raw material source, gallium contained in phosphate residues, which will
be' provided by the Monsanto Company. 
CONSUMPTION 
 The largest use of gallium was in electronic applications, principally in
the form of gallium arsenide and gallium phosphide, which are used in solid
state lamps (light-emi-tting diodes, LEDS). Due to the pronounced trend of
the electronics industry towards microminiatunization, LEDS were increasingly
used in visual display systems in calculators, digital clocks, medical instrumentation,
multiple wa-rning lights, and instrumentation for aircraft and automotive
dash -panels. A novel use for LEDS was in the production of electronic watches
in which the time display system is based on a gallium lamp matrix. The manganese-doped
magnesium-gallium spine! (MgGa2O4:Mn) is a green phosphor 
used in ultraviolet excitation and is used in fluorescent lamps in Xerox
co'pyi'ng machines. Gallium compounds were also used in semiconductor applications
for microswitching devices and in microwave and laser applications. The intermetallic
compound vanadium-gallium, V3Ga, is a superconductor with a high transition
temperature and a high critical field. 
 In research and development there was growing interest in the gadolinium-gallium
garnet, Gd3Ga5O,2, as a substrate material for magnetic bubble domain devices.
Galhum tnichlonide was investigated as a Friedel Crafts reagent in organic
synthesis. 
 1 Physical scientist, Division of Nonferrous Metals.