The 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 ... 

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. 

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... 

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. 

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... 

The thermite process (see Fig. 12.11) is used for welding railway track together. In this reaction, aluminum reduces iron(III) oxide to metallic iron ... 

There is relatively little interest in the production of pure vanadium, at least 90 per cent of the vanadium extracted being produced and used in the form of ferrovanadium alloys. These usually contain from 25 to 50 per cent vanadium and may be prepared by either of three methods (1) reduction by the thermite process (2) reduction with carbon in an electric furnace and (3) several electrolytic methods. 

Reactions of A1 with halogens at room temperature or with N2 on heating give the Al(lll) halides or nitride. Aluminium is often used to reduce metal oxides, e.g. in the thermite process (equation 12.5) which is highly exothermic. 

Before arc welding was developed, a displacement reaction involving aluminum and iron(III) oxide was commonly used to produce molten iron (the thermite process). This reaction was used, for example, to connect sections of iron railroad track. Calculate the mass of molten iron produced when 1.00 kg of aluminum reacts with 2.00 mol of iron(III) oxide. 

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