Wednesday, January 11, 2012

1957: Metallurgy


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.


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