Last edited by Nakazahn
Saturday, April 25, 2020 | History

2 edition of Zone refining. found in the catalog.

Zone refining.

Norman Lawrence Parr

Zone refining.

  • 169 Want to read
  • 39 Currently reading

Published by Royal Institute of Chemistry in London .
Written in English


Edition Notes

SeriesLectures, monographs and reports / Royal Institute of Chemistry -- 1957, no.3, Lectures, monographs and reports -- 1957, no.3.
The Physical Object
Pagination28p.,ill.,25cm
Number of Pages28
ID Numbers
Open LibraryOL19689216M


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Zone refining. by Norman Lawrence Parr Download PDF EPUB FB2

(i) Zone refining: This method is based on the principle that impurities are more soluble in the molten state of metal (the melt) than in the solid state. In the process of zone refining, a circular mobile heater is fixed at one end of a rod of impure metal. As the heater moves, the molten zone of the rod also moves with it.

ZONE REFINING Zone refining is a technique used to purify materials, mainly semiconductors by melting a short region (i.e., zone) and causing this liquid zone to travel slowly through a relatively long rod of the solid.

After going through this learning aid, learner will be able to • Interpret the concept of Zone Size: KB. Zone refining is a technique to get highly pure crystals of impure elements (specially metals) by using melting and crystallization processes.

In this a narrow region of the crystal is heated so that impurities get melted and forms a molten zone which moves along the crystal. Zone refining definition is - a technique for the purification of a crystalline material and especially a metal in which a molten region travels through the material to be refined, picks up impurities at its advancing edge, and then allows the purified part to recrystallize at.

Robert S. Feigelson, in Handbook of Crystal Growth (Second Edition), Zone Melting. Zone melting methods have played an important part in (1) purification of materials for crystal growth and other materials processing (zone refining), (2) for producing crystals with uniform composition (zone leveling) and (3) for growing crystals without crucibles (the float zone method).

&cN mar lor 0'- ZONE REFINING i*: ' 4 '96 7 -l"WIINng(on -WA A(r (*&LA 13 ' This simple technique, in which a solid is refined by passing a liquid zone through it, has been of profound value in those technologies that call for materials of extremely high purityFile Size: KB.

Other articles where Zone refining is discussed: zone melting: Zone refining is the most important of the zone-melting techniques.

In zone refining, a solid is refined by passing a number of molten zones through it in one direction. Each zone carries a fraction of the impurities to the end of the solid charge, thereby. COVID Resources. Reliable information about the coronavirus (COVID) is available from the World Health Organization (current situation, international travel).Numerous and frequently-updated resource results are available from this ’s WebJunction has pulled together information and resources to assist library staff as they consider how to handle.

(i) The technique of zone refining is based on the principle that the impurities are more soluble in the molten state of metal than in the solid state. Silicon, boron gallium, indium etc. can purify by this process. (ii) Ores of copper contain iron oxide as an impurity.

Silica reacts with iron oxide and forms iron silicate, which is removed as slag. Zone refining and allied techniques [Norman L Parr] on *FREE* shipping on qualifying offers. Additional Physical Format: Online version: Zone refining.

book, Norman Lawrence. Zone refining and allied techniques. London, G. Newnes [] (OCoLC) Document Type. In principle, zone refining takes advantage of the fact that the solubility level of an impurity is different in the liquid and solid phases of the material being purified; it is therefore possible to segregate or redistribute an impurity within the material of interest.

The molten zone moves along with the heater which is moved forward. As the heater moves forward, the pure metal crystallizes out the melt and the impurities pass on into the adjacent molten Zone Refining process is repeated several times and the heater is moved in the same direction.

At one end, impurities get concentrated. Z-Factor (Gas Compressibility) to Errors Zone Refining Reviews "High acclaim from worldwide authoritative journalsan ambitious work indeeda valuable addition to many college and industrial librarieshighly recommend[ed]to any student of the chemical process industriesprovides a valuable starting point for any specific design-related project.

Purification is a primary application of zone melting, in which the improvement of efficiency, production yield and minimum achievable impurity level are always the research focus due to the increasing demand for high purity metals.

This paper has systematically outlined the whole development of related research on zone refining of metals including basic theories, variants Cited by: 5. Zone refining definition, a process of purifying any of various metals and other materials, as germanium or silicon, by passing it in bar form through an induction coil.

See more. Zone refining is not a technique which resulted from the discovery of new principles. In retrospect one can clearly see that zone refining was a logical ex- tension of the use of the freezing or crystallization process as a means of purifi- cation.

To use crystallization as a means of purification one takes advantage of. Zone refining is a technique companies can use in the production of highly pure crystals for components like transistors.

In this method, impurities in an ingot, or mass of metal, are forced to one end or another through a series of melting and cooling leaves behind a chunk of mostly pure material available for use in seed crystals and other components.

(i) Zone refining: This method is based on the principle that impurities are more soluble in the molten state of metal (the melt) than in the solid state. In the process of zone refining, a circular mobile heater is fixed at one end of a rod of impure metal.

As the heater moves, the molten zone of the rod also moves along with it. Abstract. The article presents the results of an experimental study of the effect of impurity transport in a zone-refining system.

In order to further improve the purity of aluminum, therefore, a sample with the purity (%) aluminum material was used for zone refining, and evaluated its purity by glow discharge mass spectrometry (GDMS).

The semi conductors like Si, Ga, Ge are purified by Zone refining. it is also known as fractional crystallisation works according to the principle. Comparison of continuous zone refining with zone refining of finite and infinite ingots. The calculated carves of distribution for three cases examined (H = 16, I- I, k =n = 1) show the simi- larity of the distribution curve for continuous zone refining and the ideal distribution curve for a hypothetical infinite ingot (fig.

zone refining 1. In metallurgy, the smallscale production of high-purity metals using the principle that an impure melt will deposit pure crystals on solidifying.

A rod of the specimen is melted over a very narrow region at one end, and then the molten region is transferred along the rod by means of a moving furnace.

Source for information on zone refining: A Dictionary of Earth Sciences. (i) Zone refining Is the method based on the principle that the impurities are more soluble in the melt than in the solid state of the metal. (ii) Electrolytic refining works on the principle of refining impure metals by the use of electricity.

Zone Melting. By W. PFANN. with figs. New York: Wiley; London: Chapman & Hall. Price 60s. It is fitting that the first book on zone-melting should come from the author of the first paper on the subject; and the resulting volume goes far to meet the claim on. @article{osti_, title = {ELECTROMAGNETIC STIRRING IN ZONE REFINING}, author = {Braun, I and Frank, F C and Marshall, S and Meyrick, G}, abstractNote = {The efficiency of the zone refining process can obviously be increased by stirring the molten zone to disperse the impurity-rich layer at the solid- liquid surface.

Induction heating is sometimes preferred to. It can cause an horizon of increased liquid which will pass through the zone of crystallization with an effect similar to that of the metallurgical process of zone refining, but in this case remelting does not result from reheating but from nearly isothermal fluxing and, as a consequence, fractionation is more by: Crystal Growth, Second Edition deals with crystal growth methods and the relationships between them.

The chemical physics of crystal growth is discussed, along with solid growth techniques such as annealing, sintering, and hot pressing; melt growth techniques such as normal freezing, cooled seed method, crystal pulling, and zone melting; solution growth methods; and vapor.

Zone- Refining Meals of very high purity can be obtained by this method by removing an impurity, which shows difference in solubility of the liquid and solid states of the metal.

A circular heater is fitted around a rod of impure metal and is slowly moved down the rod. Cupellation is a process used for the refining of a) Silver b) Lead c) Copper d) iron Extraction of gold and silver involves leaching with cyanide ion.

silver is later recovered by (NEET) a) Distillation b) Zone refining c) Displacement with zinc d) liquation A numerical study has been carried out to optimize the zone refining process parameters such as zone length, zone travel rate, number of passes and.

Fun science education is the most important tool for development of nation. This website provides you the best learning experience, books and concepts of science in a joyful and funny way. || Fun science provides science education in both practical and theoretical ways.

|| If you need science projects in a funny and joyful manner then you are at the right place as you. Encyclopedia of Chemical Processing and Design: Volume 68 - Z-Factor (Gas Compressibility) Errors to Zone Refining - CRC Press Book. Zone refining is a method that is used to form pure solid crystals of different substances.

Zone-refining is based on the principle that impurities are more soluble in the molten state than in the solid state. The impure substance is placed on a heating belt which is moving continuously, a temperature gradient is maintained on the belt.

After zone refining, metallic elements were analyzed by GDOS (Glow Discharge Optical Spectroscopy) and GDMS (Glow Discharge Mass Spectrometry). The impurities Ag, Pb, S and Ti, whose distribution coefficients are belowwere concentrated at the finishing position.

High purity metals are nowadays increasingly in demand to serve in electronic, photovoltaic, and target materials industries. The zone refining process is the most common way to achieve high purity in the final step of metal purification. Zone length and crystal growth rate are the main parameters that control the zone refining process.

To determine these values, information Author: Xiaoxin Zhang, Semiramis Friedrich, Bernd Friedrich. The purpose of this study was to investigate zone refining techniques for the purification of plutonium metal.

The redistribution of 10 impurity elements from zone melting was examined. Four tantalum boats were loaded with plutonium impurity alloy, placed in a vacuum furnace, heated to {degrees}C, and held at temperature for one hour.

Physics Assignment Help, Zone refining, The semiconductor material is refined through a process is known as zone refining. It is used for the production of high purity crystals; silicon for example has a melting temperature, so any impurity present in the crystal decreases the melting temp.

Zone refining is an industrial process which makes use of the fact that a material often solidifies with a higher purity than the surrounding liquid, in order to produce materials of very high purity.

A bar is passed through a furnace that melts a small section of the bar. As the bar passes through the furnace, this section of liquid is passed.