1957:
Metallurgy
Archives consist of articles that
originally appeared in Collier's Year Book (for events of 1997 and earlier) or
as monthly updates in Encarta Yearbook (for events of 1998 and later). Because
they were published shortly after events occurred, they reflect the information
available at that time. Cross references refer to Archive articles of the same
year.
1957: Metallurgy
In 1957 the expanding world economy was reflected in
increased production facilities for all metals and related mineral products.
Production facilities of the basic work horse metals, such as carbon steel,
copper, lead, zinc, and aluminum, caught up with the demand, although the
downward trend in business conditions was reflected in a slight slackening in
steel production and a drastic drop in prices of copper, lead, and zinc. The
price of aluminum was slightly increased, but considerable aluminum metal was
stock-piled by the U.S. Government; interest in titanium continued at a steady
pace, the price of titanium sponge being reduced by over 100 per cent in the
last few years; and the ferroalloy metals, such as nickel, tungsten,
molybdenum, and chromium, continued in good demand.
In general, it could be said that urgent need for
increased production of all metals had been somewhat alleviated. The emphasis
in metal production and utilization, thus, is on instrumentation, automation
and better control of processes, and research and developments.
Steelmaking.
Production.
More steel was made in the United States in the first
eight months of 1957 than in any previous identical period. During this period
steelmaking furnaces were operated at an average of 88.5 per cent of their Jan.
1, 1957, capacity of 133,460,000 net tons annually.
During the first six months of 1957 the production of
steel in millions of net tons was 60.6 for the United States, 27.6 for Russia,
and 32.4 for the seven nations of the European Coal and Steel Community. In
spite of the slight business recession, the construction boom in the United
States continued to demand record quantities of steel for offshore oil-drilling
rigs, oil and gas pipe lines, the St. Lawrence seaway, the federal highway
program, shipbuilding, office buildings, and factories.
Iron Ores.
Three large plants for treating the large reserves of
magnetic taconites (low-grade ores of ñ30 per cent iron content) are in various
stages of construction and operation. These plants use wet magnetic separators
to produce magnetite concentrates containing more than 60 per cent iron. This
concentrate is in an extremely finely powdered state and must be agglomerated
into pellets before blast-furnace smelting; these pellets make excellent
blast-furnace feeds. By utilizing this process our iron ore reserves in
Minnesota have been greatly increased.
Iron Oxide Reduction.
Present well established blast-furnace practice
requires coke as the necessary fuel and reducing agent for the iron oxide ores.
Hydrogen gas, which can be made from natural gas, petroleum, and other
materials more widely distributed geographically than coke, has been suggested
as a substitute for coke in the iron oxide reduction process. Several large
U.S. steel companies are carrying out large-scale experiments investigating the
reduction of iron ores by hydrogen. The fluo-solids gas-solids contacting
process appears to be the means by which this process can be made feasible.
Oxygen Converter.
The use of oxygen-enriched air to increase flame
temperature and shorten treatment time in the open-hearth furnaces is
progressing. In addition, from European practice the oxygen converter has been
introduced into American practice. The new oxygen converter substitutes oxygen
for air and blows it into the top of the molten metal bath instead of through
tuyeres (special tubes) into the bottom. The use of oxygen overcomes the
excessive nitrogen content in steel, made by the converter process using air.
As compared to the open-hearth process, the new oxygen converter cuts
production costs through lower fuel costs, the only added fuel being oxygen;
oxygen converters can produce about three times as much steel. To realize the
advantages of this relatively new process, several large-scale installations of
these oxygen converters are being contemplated.
Research.
Continuous casting processes for steel are being
seriously investigated. Special steels for guided missiles and jet engines are
being developed.
Nonferrous Metals.
Copper.
The copper industry was highlighted by the further
discovery and delineation of large low-grade ore deposits in the United States
and South America and the planning, actual construction, and initial operations
of copper extraction plants utilizing these deposits. Wherever possible
open-pit mining methods are being used, utilizing the great progress in large
rock-moving equipment.
The problem of treating mixed oxide and sulphide
copper ores is being solved by the leach-precipitate-float (LPF) process: the
oxide ores are dissolved in acid; the copper in solution is precipitated by
metallic iron; and both sulphide copper minerals and precipitated metallic
copper are separated from the ore pulp by froth flotation.
Better refractories and the use of a suspended arch
roof over the large reverbatory smelting furnace are improvements. The
application of thermodynamic reasoning is receiving considerable attention and
appears promising as a means of producing a better understanding of chemical
reactions in copper smelting and improved processes.
Zinc.
Zinc smelting moved a step forward with the successful
development of blast-furnace zinc smelting in England. By this process
zinc-bearing charges of various grades and mixed lead-zinc ores and
concentrates may be treated. Lead content of the charge is simultaneously
recovered as lead bullion; precious metals and antimony are collected in the
lead bullion. This important smelting development has been proven on a large
scale. It rivals the continuous-retort and electro-thermic smelting processes
previously perfected in America; in the treatment of some complex raw materials
it may show some advantages. Shock-cooling of metallic zinc vapor by means of a
circulating molten lead spray is the key to the success of the new process. A
considerable saving in fuel is accomplished.
Aluminum.
Aluminum continues to be used in increasing quantities
for new uses. Construction displaced the transportation field as the biggest
single market for the aluminum industry. Aluminum metal is supplementing and in
some places being substituted for copper in electrical conductors. Packaging in
aluminum is an expanding field.
Boron.
Boron compounds are being developed as high-energy
solid fuels to increase range, speed, and payload of present jet planes and
missiles and to make possible radical new projectiles. Boron combines with
hydrogen (sodium borohydride) to form a high-energy fuel which is easy, safe to
handle, and can be produced at relatively low cost. One gram of boron, for
example, yields 4,000 calories; carbon, 8,000. However, decaborane (10 g. boron
to 14 g. hydrogen) yields 16,000 cal. Boron is also used as a steel-hardening
ingredient; a small amount of boron may displace larger amounts of relatively
scarce ferroalloy metals formerly used.
Nuclear Energy Applications.
Uranium Ores.
The Atomic Energy Commission released statistics
showing that in 1957 there have been discovered within the territorial United
States 67 million tons of uranium ore averaging 0.27 per cent U3O8content.
Twelve processing mills are operating and twelve more are under construction or
contracted to produce uranium ores. In addition, ion-exchange and
solvent-extraction processes have proven successful for treatment of uranium
ores.
Atomic Reactors.
Intensive research into the possibility of controlling
fusion, or the thermonuclear reaction of the hydrogen bomb, for the production
of useful power is being carried on in the United States and foreign countries.
The most likely fuel for the fusion power reactor would be deuterium or heavy
hydrogen. At present, zirconium is being produced in considerable tonnages and
is the major construction material for the new atomic reactor power plants.
Metal Science.
Cermets, the name given to a material which is partly
metal and partly a refractory oxide with a high melting point, have been used
in jet engine parts exposed to severe high-temperature conditions.
The high-melting-point metals, semiconductors, and
some heretofore rare metals, such as beryllium, titanium, zirconium, chromium,
hafnium, columbium, and tantalum, are the subject of a great deal of research
and development. Titanium, for example, may furnish a whole series of
light-metal alloys, especially useful as corrosion-resistant, high-temperature
structural materials for aviation and the missile program.
Zone refining processes have been developed to produce
ultra pure metals such as silicon, molybdenum, tungsten, germanium, and others,
containing in many cases only a few parts per million of impurities. These
ultra pure metals possess extraordinary high strength and desirable physical
and chemical properties. Much research work is being performed on the
production of single crystals of these pure metals. The detection, analysis,
and possible prevention of dislocations produced by impurities in metallic
crystal structures give promise of metals with properties superior to those of
metals presently being produced.
No comments:
Post a Comment