Evening star., 1942-06-18
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Laboratory, Field
And Study
By Thomas r. Henry.

A method OF securing 80 per cent pure
chromium metal from low-grade Amer
ican ores has been found by metal
lurgists of the United States Bureau of
Mines after more than five years of re-
search.
Chromium Is one Of the most vital
of war metals. Its chief value is to form
alloys with steel which are very strong
and rustproof. These alloys are best
known in the form of automobile finish
ings and bathroom fixtures, but they
have hundreds of essential uses unfa-
miliar to the general public.
America uses about $4,000 tons Of the
metal a year, but in the past has pro-
duced only about 5000 tons. Most Of the
rest has come from South Africa and
from Turkey. The Turkish deposits,
perhaps the largest in the world, have
been considered a major reason why
Germany, with no chromium of It's own,
might launch an invasion of that coun-
try.
There are deposits in Alaska, Califor-
mia. Oregon, Montana, Washington and
Wyoming, but for the most part they are
of low grade and expensive to work. The
new process, Bureau Of Mines experts
believe, may permit the utilization OF
large amounts of this ore, and extensive
surveys are under way to discover other
deposits.
In the past the metal used in industry
has been in the form of ferro-chromium
about so to 10 per cent chromium
mixed with iron.
This is considered good enough for
most industrial purposes. Its extraction,
however, is not much less expensive
than that of the pure metal-in some
cases it may be 9sS per cent pure-by
the new process reported by C. G.
Maier of the bureaus staff.
A pilot plant is planned to be operated
by the Government in order to deter
mine the actual cost Of large-scale pro-
duction from the type OF ores available
in the United States. Although con-
siderable stocks of the foreign metal
presumably have been piled up for war
purposes there is little likelihood OF
extensive replacements with the present
shipping situation.
The pure metal is obtained in pow
dered form, most suitable for the forma-
ton of alloys. A major drawback in
the present emergency is that the proc
ess requires large quantities OF the gas
chlorine one of the most essential of all
war chemicals. A shortage of this for
a score or more of civilian uses, from
cleaning suits to preserving stored grain,
already is being reported.
Hitherto, Mr.. Maier reports. there
have been only minute amounts OF pure
chromium metal and these have been
laboratory curiosities.
Immediate benefits of the improved
form of chromium metal, according to
DR.. r. r. Sayers. director Of the Bureau
of Mines, probably will be the develop
ment of new and important anoying
processes. The high purity and pow
dered form render it valuable in the
manufacture of special steels, brass and
bronze materials, and in alloys that are
subject to high temperatures. such as
electrical heating elements. An import
ant use of chromium in the past has
been for Innings of furnaces subjected to
great heat.
The practicability Of the process, DR..
Sayers says, will depend for the present
largely on the availability and cost of the
essential chlorine The chlorine and
chromium are combined in a gas at
high temperatures. This gas does not
take up other impurities in the ore. Then
the two chief constituents are separated,
leaving the pure metal.