Extractive metallurgy reduction

The essential operations of an extractive metallurgy flow sheet are the decomposition of a metallic compound to yield the metal followed by the physical separation of the reduced metal from the residue. This is usually achieved by a simple reduction or by controlled oxidation of the nonmetal and simultaneous reduction of the metal. This may be accompHshed by the matte smelting and converting processes. 

The preparation, reduction, and refining operations are very much interdependent, and for a given metal must be considered as parts of a single flow sheet. To illustrate the principles of extractive metallurgy, however, it is convenient to discuss the various operations separately. 

D. J. I. Evans, Production of Metals by Gaseous Reduction from Solution Processes and Chemistry in Advances in Extractive Metallurgy p. 831, IMM, London, 1968. 

The reaction equations of the cycle using liquid Pb are shown in Table IV. As a means of preparing Pb from PbS, the roast-reaction or air-reduction method is well-known in nonferrous extractive metallurgy. The reactions for this method can be presented as follows ... 

The reactions of metals to form stable halides are important for various reasons. The metal halides generally have low boiling points and high volatiUty. For this reason, they are used in several important processes for the production and refining of metals, such as the reactive metals titanium and zirconium. These metals are produced using the Kroll process, in which the metal oxide is converted to metal chloride or fluoride, which is then reduced to metal. This route avoids several formidable difficulties involved in the reduction of the oxides of these metals. Details of these processes can be found in extractive-metallurgy textbooks. 

Harper, J. and Williams, A. E. Factors Influencing the Magnesium Reduction of Uranium Tetrafluoride. I.M.M. Symposium on the Extraction Metallurgy of Some of the Less Common Metals, London (1956). 

REACTION MECHANISMS AND PRODUCT MORPHOLOGIES ON GASEOUS REDUCTION OF METAL COMPOUNDS - Extractive Metallurgy meets Materials Science... 

Extractive metallurgy refers to the process of extracting a metal from its ores. Generally this occurs in four steps. Concentration separates the ore from waste rock (gangue). Roasting converts the ore to the metal oxide. Reduction (usually with carbon) converts the oxide to the metal. Refining removes impurities from the metal. 

A reduction process is one in which electrons are "gained" and the oxidation state of some atom decreases. (Reduction can only occur in combination with oxidation.) (See also extractive metallurgy.)... 

Metallurgy, the science of extracting and purifying metals from their ores, makes use of numerous redox processes. We ll see in Section 21.2, for example, that metallic zinc is prepared by reduction of ZnO with coke, a form of carbon ... 

Metallurgy is the commercial extraction of metals from their ores and the preparation of metals for use. It usually includes several steps (1) mining the ore, (2) pretreatment of the ore, (3) reduction of the ore to the free metal, (4) refining or purifying the metal, and (5) alloying, if necessary. ... 

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