USES OF THE PLATINUM METALS.
In
discussing the uses of platinum in war it is not practicable to confine
the discussion to that metal alone, for several metals of the platinum
group are useful in war and must be considered together. These metals
are platinum, iridium, palladium, rhodium, osmium, and ruthenium. The
first four named are of commercial and military value; the last two
are, "so far as known, of little commercial value. The natural alloy of
osmium and iridium, that is called osmiridium or iridosmine, is used
commercially in a small way.
Pure
platinum is required by the Government in very large quantities for
use in the "contact process" of making sulphuric acid and for use at
the new plants erected for the fixation of nitrogen. It is needed also
for making utensils and apparatus at a great number of chemical
laboratories, which control our whole industry. Finally, large
quantities of platinum and iridium are required for all kinds of
electrical equipment.
The
so-called platinum used in electrical work is an alloy of platinum and
iridium, and the alloy used for some work may carry as high as 50 per
cent of iridium. Each telephone and telegraph instrument has platinum
contacts; every high-grade magneto for an airplane, automobile, motor
boat, or gas engine has from two to six contacts of platinum; and the
multitude of contacts on telephone switchboards and the relay
instruments of both telephone and telegraph lines are of platinum. For
some purposes in electrical work satisfactory substitutes for piatmum
have been found and are being used; for other purposes substitutes will
probably soon be used; but for many high-duty electrical contacts no
satisfactory substitutes have yet been found. Pure iridium is
apparently of little commercial use. It is em-ed principally as a
hardening element in the platinum-iridium alloys used in the electrical
industry and by jewelers. Jeweler's platinum contains an average of 10
per cent of iridium, though some alloys that run as high as 15 per cent
of iridium are used for certain work. Therefore, every 100 ounces of
piatmum used in the jewelry trade contains 10 ounces of iridium, to
produce which it is necessary to obtain and refine approximately 200
ounces of Russian or 630 ounces of Colombian crude platinum. The alloys
used in the electrical industry contain from 15 to 50 per cent of
iridium, and the average alloy used in electrical work doubtless
contains 20 per cent of iridium. To obtain 100 ounces of electrical
platinum it is therefore necessary to refine 400 ounces of Russian or
1,260 ounces of Colombian crude platinum.
