43 resultados para Tungsten ores
Resumo:
Zinc is produced from ores by two general methods, distillation and electrolysis. The general principles involved in the electrolytic zinc process of today were known as far back as 1880. Difficulties encountered in purifying the solution for electrolysis and lack of suitable mechanical apparatus were the main reasons that such a long time elapsed before the process was used to produce zinc in commercial quantities.
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An amalgam is an alloy of mercury with other metals, and amalgamation is the art of making or forming amalgams. In metallurgical language the word is limited to the means adopted for the recovery of gold and silver from their ores by the use of mercury.
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Since the development of cyanidation into a highly efficient process for treating gold ores, many papers have been written on its various aspects. Although, there has been much work done on it, the chemistry of the reaction is not yet completely understood.
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Today considerable work is being done in the compressed metal powder field which is gradually obtaining prominence as a valuable branch of metallurgy. The mass of data, however, has led to many different ideas on the results of sintering.
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In metallurgical practice today some of the relatively rare metal Indium is recovered as a by-product from the ores of other metals. Indium is a soft, silvery—white metal belonging to the third group of the periodic classification. It is situated just above tin in the electrochemical series.
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The Purpose of this thesis was to investigate the possibility of concentrating scheelite from Wilfley table gold concentrates from the mill of the Jardine Mining Company; and to determine whether such concentration is economically feasible and the product of sufficiently high grade to meet commercial specifications for such a product.
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The cyanide method of extraction of gold and silver from their ores is extensively used in the United States and elsewhere. It is becoming increasingly more important in its use as the mining of lower grade deposits continues.
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Little has been written on pegmatites in Montana except in conjunction with reports on mining districts. This subject was chosen as a senior thesis to see what facts could be ascertained regarding pegmatites alone, and an attempt has been made by the writer to assemble all written material on pegmatites in southwestern Montana, and to study specimens from those that could be reached or from which specimens were available.
Resumo:
Powder metallurgy is a branch of metallurgy which produces metallic compacts in their final forms by means of pressure and heat-treatment from the powders. The products of powder metallurgy are being used in our daily lives quite often. For example, the tungsten wires in the electric bulbs to the silver-tin fillings of our teeth.
Resumo:
It is known that there are large deposits of chromium ore in Stillwater and Carbon Counties in South-Central Montana. The late James F. Kemp of Columbia University, stated in 1928, that these were the largest chromium deposits in the United States and probably in the world, although they were not considered of commercial grade as compared with foreign ores.
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Powder metallurgy, the most recent innovation in metallurgical process, is not a new art; although not until recently did it become a matter of general interest, this being due not only to the products formed but also to the possibilities of future developments. The manufacture and application of metal powders is now beginning to take a position as a recognized part of the science of metallurgy.
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With the increasing importance of manganese in the metallurgical fields of today and tomorrow, extensive work along the lines of its successful exploitation has been accomplished by many investigators. Since tie current world situation has shut off most of our supply of high-grade manganese ores from foreign sources, the low-grade domestic deposits have entered the fields of investigation very rapidly.
Resumo:
The authors describe the design, fabrication, and testing of a passive wireless sensor platform utilizing low-cost commercial surface acoustic wave filters and sensors. Polyimide and polyethylene terephthalate sheets are used as substrates to create a flexible sensor tag that can be applied to curved surfaces. A microfabricated antenna is integrated on the substrate in order to create a compact form factor. The sensor tags are fabricated using 315 MHz surface acoustic wave filters and photodiodes and tested with the aid of a fiber-coupled tungsten lamp. Microwave energy transmitted from a network analyzer is used to interrogate the sensor tag. Due to an electrical impedance mismatch at the SAW filter and sensor, energy is reflected at the sensor load and reradiated from the integrated antenna. By selecting sensors that change electrical impedance based on environmental conditions, the sensor state can be inferred through measurement of the reflected energy profile. Testing has shown that a calibrated system utilizing this type of sensor tag can detect distinct light levels wireless and passively. The authors also demonstrate simultaneous operation of two tags with different center passbands that detects light. Ranging tests show that the sensor tags can operate at a distance of at least 3.6 m.
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At the present time ore bodies being mined are becoming more and more complex in mineral association, thus presenting a more difficult problem in their concentration. Lead-zinc sulphide ores are among the more common ores which present such difficulties.
Resumo:
This thesis is concerned primarily with the production of metal powder compacts of iron and tin. In producing these compacts, the effects of processing variables on some of the essential properties of the pellets made were investigated.