Metallurgy development

Prehistoric metallurgy developed empirically. It was handed down from teacher to student and hence improved only slowly. In antiquity, seven elements (according to today s definition) were... 

Not much is known of the element s use until the knowledge of metallurgy developed in the late eighteenth century, when arsenic, antimony, and bismuth were used to form alloys with other metals. 

The original interest in these excavated samples stemmed from the important role of bronze and the historical implications of the extensive tin trade routes in the Middle Bronze Age (2200-1600 B.C.). As bronze metallurgy developed from the earlier use of copper and arsenical copper, tin sources became vital (14). By the Middle Bronze Age, the limited distribution of tin deposits throughout the world and the ample supply of copper were well-known, and extensive tin trade routes had been established to supply the metallurgical centers of the world with this then-considered precious metal (15-16). The Ugaritic tablets from Ras Shamra, however, indicate a severe drop in the value of tin around the Late Bronze Age (1400-1200 B.C.). It has been postulated (17) that this drop was related to the discovery of more accessible sources of tin. 

An early copper metallurgy developed when some craftsmen - who were surely considered to be in contact with the gods - acquired knowledge about what type of earth (containing a copper oxide mineral) should be mixed with charcoal to give the... 

The Ukrainian Research Institute of Pipes and Metallurgy Automation Research Institute have effective developments in the field of NDT in metallurgy (pipes and rolled stock). Other organisations were experts are working with success in the NDT field are ... 

Technological History. In the history of technology, the developments of metallurgy probably provide the most compHcated and important chapter. Although new archaeological evidence continually necessitates changes in accepted hypotheses regarding the developments in the use of metals in... 

A. R. E. Singer and A. D. Roche, ia E. N. Aqua and C. I. Whitman, eds.. Modem Developments in Powder Metallurgy Metal Powder Industries... 

Production of a metal is usually achieved by a sequence of chemical processes represented as a flow sheet. A limited number of unit processes are commonly used in extractive metallurgy. The combination of these steps and the precise conditions of operations vary significantly from metal to metal, and even for the same metal these steps vary with the type of ore or raw material. The technology of extraction processes was developed in an empirical way, and technical innovations often preceded scientific understanding of the processes. 

H. H. Hausner, ed., "Modem Developments in Powder Metallurgy," Proceedings of the International Powder Metallurgy Conference of New York, 1966, Plenum Press, New York, 1966. 

The treatments used to recover nickel from its sulfide and lateritic ores differ considerably because of the differing physical characteristics of the two ore types. The sulfide ores, in which the nickel, iron, and copper occur in a physical mixture as distinct minerals, are amenable to initial concentration by mechanical methods, eg, flotation (qv) and magnetic separation (see SEPARATION,MAGNETIC). The lateritic ores are not susceptible to these physical processes of beneficiation, and chemical means must be used to extract the nickel. The nickel concentration processes that have been developed are not as effective for the lateritic ores as for the sulfide ores (see also Metallurgy, extractive Minerals recovery and processing). 

E. L. Rees, F. W. Heck, and G. A. DiBari, Modem Developments in Powder Metallurgy, Vols. 18—21, Metal Powder Industries Federation, Princeton,... 

Much of the technology used in the reclamation of metals from metal-bearing wastes was developed by the mining iadustries. The primary means of recycling metal from metal and alloyed scrap is via pyrometaHurgy (see Metallurgy). 

Ladle metallurgy, the treatment of Hquid steel in the ladle, is a field in which several new processes, or new combinations of old processes, continue to be developed (19,20). The objectives often include one or more of the following on a given heat more efficient methods for alloy additions and control of final chemistry improved temperature and composition homogenisation inclusion flotation desulfurization and dephosphorization sulfide and oxide shape control and vacuum degassing, especially for hydrogen and carbon monoxide to make interstitial-free (IF) steels. Electric arcs are normally used to raise the temperature of the Hquid metal (ladle arc furnace). 

Development in Dadle Steelmaking and Continuous Casting, Canadian Institute of Mining, Metallurgy and Petroleum, Montreal, Quebec, Canada, 1990. 

Nonferrous Metal Production. Nonferrous metal production, which includes the leaching of copper and uranium ores with sulfuric acid, accounts for about 6% of U.S. sulfur consumption and probably about the same in other developed countries. In the case of copper, sulfuric acid is used for the extraction of the metal from deposits, mine dumps, and wastes, in which the copper contents are too low to justify concentration by conventional flotation techniques or the recovery of copper from ores containing copper carbonate and siUcate minerals that caimot be readily treated by flotation (qv) processes. The sulfuric acid required for copper leaching is usually the by-product acid produced by copper smelters (see Metallurgy, extractive Minerals RECOVERY AND PROCESSING). 

It maybe economical, therefore, to use these materials at or near the cutting edge instead of as the whole insert. The development of tools of TiC (40—55%) or TiN (30—60%) in a steel matrix on a steel core using powder metallurgy technology suggests a similar approach for cemented carbides as the need arises. 

The first appHcation of the gas turbine principle to a ground system was in 1906 when waste heat from furnace gases was used to operate a turboblower which compressed air for a blast furnace. Developments in metallurgy and compressor design after World War I led, in 1937, to the first... 

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