Thermite Process

Thermit-bom be, /. thermite bomb, -brand-bombe, /. thermite incendiary bomb, -fiil-iung, /. thermite filling or charge, -ladung, /. thermite charge, -schweissung,/. thermite weld(ing). -verfahren, n. thermite process. 

The true alkaline earth metals—calcium, strontium, and barium—are obtained either by electrolysis or by reduction with aluminum in a version of the thermite process (see Fig. 6.8) ... 

Chromium metal is also reduced by aluminum in the thermite process ... 

A rich supply of manganese lies in nodules of ore that litter the ocean floors (Fig. 16.9). These nodules range in diameter from millimeters to meters and are lumps of the oxides of iron, manganese, and other elements. However, because this source is technically difficult to exploit, manganese is currently obtained by the thermite process from pyrolusite, a mineral form of manganese dioxide ... 

In a thermite process to produce chromium metal, the mechanically-mixed ingredients were ignited in a large crucible and the reaction proceeded smoothly. When the mixer broke down, manual mixing was used but gave poorer dispersion of the constituents. An explosion after ignition is attributed to a high local concentration of sodium chlorate and aluminium powder in the mixture. 

Self-propagating reduction reactions Several oxide reduction solid-state reactions have been known for a long time. Starting materials are considered which react together highly exothermically. Once the reaction is initiated, enough heat is produced for very high temperature to be attained, and complete reaction occurs rapidly. The so-called thermite process corresponds to the reactions ... 

Manganese(II,III) oxide occurs in nature as the mineral hausmannite [1309-55-3]. It is used to make ferrites and thermistors. The oxide also is used in the thermite process for producing manganese. 

Manganese(lI,III) oxide is reduced to manganese metal when heated with powdered aluminum (the Thermite process). The reaction is vigorous and exothermic ... 

One of the most energetic examples of chemical replacement is so powerful that it produces molten iron. This makes it very useful in remote places for on-the-spot repairs to iron structures. Called the Thermit process, it uses a mixture of powdered aluminum metal and iron oxide. 

Modifications of the Goldschmidt thermite process may also be employed for the preparation of the iron-vanadium alloy. The crushed vanadates or vanadium pentoxide are mixed with the necessary amount of iron scalings or turnings and fluxes, and introduced into a gas-fired open-hearth furnace or into an iron crucible provided with a refractory lining and previously heated to redness. The reactions taking place are ... 

The comparatively high heat of formation of vanadium pentoxide and the tendency of aluminium to alloy with metallic vanadium explain the non-success of the application of the thermite process for the production of pure vanadium from the pentoxide and from vanadates. 

The malleability and ductility of tantalum are destroyed by the presence of even traces of foreign bodies 0-1 per cent, of carbon, for instance, renders the material brittle. Older laboratory reactions which gave rise to more or less pure tantalum deficient in mechanical properties consisted in reducing tantalum pentoxide with mixed metal (see p. 134) or with carbon in the electric furnace 3 the equilibrium conditions of the reduction of tantalum pentoxide by carbon at high temperatures have been investigated by Slade and Higson.4 The thermite process yields an alloy of tantalum and aluminium.5... 

Aluminium alloys well with up to about 3-5 per cent, of tantalum, which has no effect, however, on the mechanical strength, ductility, and working properties of aluminium.3 Reduction of tantalum pentoxide by the thermite process yields hard, brittle alloys.1 A substance the composition of which corresponds with the formula TaAls has been obtained by reducing potassium tantalum fluoride, K2TaF7, with aluminium filings at a high temperature. It is described as an iron-grey crystalline powder, of density 7-02, which is scarcely attacked by acids.5... 

GOLDSCHMIDT REDUCTION PROCESS. Reaction of oxide), of various metals with aluminum lo yield aluminum oxide and the free metal. This inaction has been used to produce certain metals, e g. chromium and zirconium, from oxide ores and it is also used in welding (iron oxide plus aluminum giving metallic iron and aluminum oxide, plus considerable heat). (Thermite process. ... 

The thermite process, in which aluminum is a vigorous reducing agent, is also used to reduce other metals from their ores. 

The field of pyrots presents, by far, the widest usage of Si. Its use includes ignition compns, delay trains, variations of the thermite processes, and mass-produced ordnance items... 

The thermite process is of historical interest as a method of welding iron ... 

Between 40% and 50% of the roasted concentrate is converted to ferromolybdenum, either by means of an electric furnace or by a thermite process. The thermite process involves ignition of a mixture of the roasted concentrate with aluminium and an iron source (iron ore and ferrosilicon) together with a flux. The resulting ferromolybdenum contains between 55% and 70% of molybdenum, and is used in alloy steel and cast iron manufacture. Some of the roasted concentrate is converted to briquettes by pressing with a pitch binder. The briquettes, weighing about 5 kg., are also used in manufacture of alloy steels and cast irons. 

Properties of the Alumwa-Based Ceramic Layer Produced by the Centrifugal Thermite Process"... 

In Japan, several commercial projects have been reported in the literature. For example, at the National Research Institute for Metals, the NiTi shape-memory alloy is produced by combustion synthesis from elemental powder for use as wires, tubes, and sheets. The mechanical properties and the shape-memory effect of the wires are similar to those produced conventionally (Kaieda et ai, 1990b). Also, the production of metal-ceramic composite pipes from the centrifugal-thermite process has been reported (Odawara, 1990 see also Section III,C,1). 

Odawara, O., Long ceramic-lined pipes produced by a centrifugal-thermite process. J. Am. Ceram. Soc., 73,629 (1990). 

The thermite process may be the original inspiration of combustion synthesis (CS), a relatively new technique for synthesizing advanced materials fl-om powder into shaped products of ceramics, metallics, and composites. Professor Varma and his associates at Notre Dame contributed the article Combustion Synthesis of Advanced Materials Principles and Applications, which features this process that is characterized by high temperature, fast heating rates, and short reaction times. 

Cr, at wt 5Z01 steel-gray, hard cryst metal, mp 1903 + lO pp 2642, d 7.14 at 2y , vap pressure Imm at 1616° insol in w in nitric acid sol in HCl, strong alkalies and dil sulfuric acid. Can be prepd by reducing chromic oxide, Cr20, by the thermite process using powdered A] or by other methods (Refsl,2,3,4,5,6,8 10). The... 

Muller, W., Lab-Scale R D Work on Fission Product Solidification by Vitrification and Thermite Processes, Report KFK 1743, Kem-forschungszentrum Karlsruhe, Karlsruhe, West Germany, 1972. 

Vitrification and Thermite Processes, in Proc. Symp, Manage, Radioactive Waste from Fuel Reproc, Paris, Nov. 27-Dec. 1, 1972, USAEC Report CONF-721107, 655, March 1973. 

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