Flash smelting

Reduction to Liquid Metal. Reduction to Hquid metal is the most common metal reduction process. It is preferred for metals of moderate melting point and low vapor pressure. Because most metallic compounds are fairly insoluble in molten metals, the separation of the Hquified metal from a sohd residue or from another Hquid phase of different density is usually complete and relatively simple. Because the product is in condensed form, the throughput per unit volume of reactor is high, and the number and si2e of the units is rninimi2ed. The common furnaces for production of Hquid metals are the blast furnace, the reverberatory furnace, the converter, the flash smelting furnace, and the electric-arc furnace (see Furnaces, electric). 

Flash smelting is efficient because the fuel value of the sulfur and iron in the charge is fully used, and the productivity (8—12 t/d of charge processed per square meter of hearth) is higher than that of the reverberatory or electric furnace. 

Two processes, developed for the direct processing of lead sulfide concentrates to metallic lead (qv), have reached commercial scale. The Kivcet process combines flash smelting features and carbon reduction. The QSL process is a bath-smelting reactor having an oxidation 2one and a reduction 2one. Both processes use industrial oxygen. The chemistry can be shown as follows ... 

Fig. 5. Flash smelting process and equipment, (a) The Mitsubishi process. Courtesy of the Society of Mining Engineers (23). (b) Cutaway view of an...

Fig. 6. Flash smelting-flash converting process for continuous production of metallic copper. Courtesy of Keimecott Corp.

The Inco flash smelting process produces a very high strength sulfur dioxide gas by using pure oxygen for smelting. Liquid sulfur dioxide is obtained upon compression. 

In Western Mining s flash smelting proeess, reaetion air is preheated to 480°C (920°F) and enriehed until the oxygen eontent is 24%. The reaetion eharge and eombustion air are mixed, and heat for smelting eomes from the eombustion of fuel oil (some of it present in the flux) and sulfur in the eoneentrate. The proeess yields matte, a refined ore with 44% niekel eontent. 

Flash smelting is the most common process, but electric smelting is used for more complex raw materials when increased flexibility is needed. Both processes use dried concentrates. Electric smelting requires a roasting step before smelting to reduce sulfur content and volatiles. Older nickel-smelting processes, such as... 

Pollution prevention is always preferred to the use of end-of-pipe pollution control facilities. Therefore, every attempt should be made to incorporate cleaner production processes and facilities to limit, at source, the quantity of pollutants generated. The choice of flash smelting over older technologies is the most significant means of reducing pollution at source. Sulfur dioxide emissions can be controlled by ... 

Kivcet [A Russian acronym meaning vortex oxygen electric smelting ] A flash smelting process for sulfide ores, using oxygen. In 1990, three plants had been built in Russia, one in Italy, and one in Bolivia. 

Outokumpu [Named after a hill in Finland, near Kuusjarvi] A flash-smelting process for sulfide ores, ft is an energy-efficient process (also called an autogenous process), using mainly the heat of combustion of the contained sulfur to sulfur dioxide, rather than ary external source of heat. Developed R Bryk and J. Ryselin at the Haijavalta works of Outokumpu Oy, Finland, in 1946. Used mainly for copper ores, but also for nickel, iron, and lead by 1988, 40 plants were using the process worldwide. 

Outlier detection, in chemometrics, 6 56-57 Outokumpu flash smelting, 16 146 Outokumpu lead smelting process, 14 745 Outokumpu Oy process, selenium recovery via, 22 83... 

These sources are detailed in the book, but our main subject is production of sulfuric acid from S02(g). Readers interested in smelting and roasting offgases might enjoy our other books Extractive Metallurgy of Copper (2002) and Flash Smelting (2003). 

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