Thermite reduction

By reduction of the trioxide with carbon.2 (5) By the thermite reduction process.3 A product which was 99 per cent pure has been obtained by this method or by reduction with vanadium carbide. (6) By electrolysis of a solution of the trioxide in fused calcium vanadate.4 The anode is made of carbon and the cathode is prepared by pulverizing ferro-vanadium and pressing the powder into a cone-shaped form. The current density used is 4.5 amperes per square inch of anode surface. 

Key words CuCr alloy, thermit reduction, inclusions Abstract... 

Dou Z H, et al. Research on Inclusions in CuCr Alloy Prepared By Thermit Reduction (Paper presented at the 3rd International Symposium on High-Temperature Metallurgical Processing -TMS 2012 Aimual Meeting and Exhibition, Oakland, California, March,2012),265-270... 

Dou Zhihe et at. Preparation of CuCr Alloy by Thermit Reduction Electromagnetic Stirring, Journal of University of Science and Technology Beijing, 14(6) (2007X538... 

DOU Zhihe, The Primary Research on Preparation of CuCr alloy by Thermit Reduction . (Engineering doctoral thesis, Northeastern University, 2008)... 

Research on Inclusions in CuCr Alloy Prepared by Thermit Reduction..247... 

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) ... 

In practice, the production of vanadium by aluminothermic reduction is also governed by some other considerations. The reduction has to be carried out under an inert atmosphere (helium or argon) to avoid nitrogen pick-up from the air by vanadium metal. The composition of the oxide-aluminum charge has to be so chosen that the thermit (metal obtained by aluminothermic reduction) contains between 11 and 19% aluminum. This is necessary for the subsequent refining step in the vanadium metal production flowsheet. Pure vanadium pentoxide and pure aluminum are used as the starting materials, and the reduction is conducted in a closed steel bomb as shown in Figure 4.17 (C). 

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 ... 

The basic reaction underlying the combustion of many gasless delay formulations is the Goldschmidt or thermite reaction where a metal powder and a metallic oxide interact in an oxidation-reduction reaction manner with the evolution of a large amount of heat but very little or no gas. Consequently, these formulations are used where no vent or very little vent is provided in the ammunition. Gasless delay formulations tend to burn faster under higher consolidation as the points of contact of fuel and oxidizer increase. This is because the reaction in this case is a solid state reaction by diffusion. 

The most powerful reductants for the oxides shown in Fig. 17.9 are aluminum, magnesium, and calcium. Scrap aluminum can be used in the thermite reaction to reduce metal oxides, for example, C Os ... 

Much heat is generated, and the mixture becomes white-hot. Indeed, thermite reactions have been used to generate intense heat as well as the reduced metal for certain welding applications. Chromium, however, is usually made by coke reduction of chromite (FeC CU) m the electric furnace. The product is ferrochrome, an Fe-Cr alloy, but this is acceptable if, as is often the case, the intention is to make stainless steel. 

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. ... 

Reduction of metal oxides by other metals (Figure 10.6, p. 154). Demonstrate the Thermit reaction and the reactions between the metals magnesium, zinc, iron and copper and their oxides. This will establish an order of reactivity for these metals. Some of these reactions are very violent so the use of small quantities and a rehearsal before the class demonstration are essential. R... 

Calculate the AH0 for reduction of ferric oxide by aluminum (thermite reaction) at 25°C. 

Casting under gas pressure is similar to conventional SHS production (see Section II,B,1). The reduction-type initial mixture (e.g., Cr03-l-Al-l-C,W03-l- Al-I-C) is placed in a casting die and the reaction initiated under an inert gas pressure (0.1-5 MPa) to prevent product sputtering by gas evolution from the thermite reaction (Merzhanov et al., 1980 Yukhvid, 1992). Increased gas pressure was shown to decrease sputtering significantly, and subsequent product loss (see Fig. 8). 

The reagent is prepared in ether solution by reduction of diphenyltin dichloride (Metal and Thermit Corp.) with lithium aluminum hydride. It can be isolated by crystallization from petroleum ether-methylene chloride, but solutions in benzene are only moderately stable at room temperature. 

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