Arc furnace slag

Iron and steelmaking Steel slag (general) blast furnace slag steel converter slag AOD process slag electric arc furnace slag... 

Arc furnace slag is also usually lime rich. It may be obtained in granulated (glassy) form, and may be used in a similar way as granulated blast furnace slag. 

A white cement has also been produced by jointly grinding an electric arc furnace slag with gypsum. Such a binder may also be combined with srritable pigments to produce colored cements, but these are only very rarely used. 

Open-Arc Furnaces. Most of the open-arc furnaces are used in melting and refining operations for steel and iron (Fig. 1). Although most furnaces have three electrodes and operate utilizing three-phase a-c power to be compatible with power transmission systems, d-c furnaces are becoming more common. Open-arc furnaces are also used in melting operations for nonferrous metals (particularly copper), slag, refractories, and other less volatile materials. 

Titanium slag and synthetic mtile are also used as raw materials in the production of titanium whites. Titanium slag results from a metaHurgical process during which iron (qv) is removed from ilmenite by reduction with coke in an electric arc furnace at 1200—1600°C. Under these conditions, iron oxide is reduced to metal, melts, and separates from the formed titanium slag. Titanium slag contains 70—75% Ti02 and only 5—8% iron. 

The principles pertaining to carbon blast furnace hearths apply as well to submerged-arc furnace hearths. In some processes, such as in d-c arc furnaces, the electrical conductance of carbon is a most important factor. The long life of carbon linings in these appHcations is attributable to carbon s exceptional resistance to corrosive slags and metals at very high temperatures. 

The technology for the production of titania slag by direct reduction smelting in electric arc furnaces (particularly for smelting of iron titanates and ilmenites having lower amounts of titania) is very old and the process has been in vogue in Canada, Norway, South Africa,... 

Submerged arc smelting process Pre-reduction of ilmenite (50% Ti02) followed by smelting in arc furnace to yield pig iron and titania slag (87% Ti02) TINFOS, Norway... 

Tin slags account for a sizeable fraction of the world s tantalum production. These slags are melted in electric arc furnaces, together with coke and lime (as flux), and this pyrometallurgical process leads to the production of synthetic niobium/tantalum concentrates. The waste products of this operation are mechanically separated slags which can be used, for instance, as landfill. The exhaust gases from this process are of minor consequence if dust is eliminated by the use of filters. 

For the most part, the zinc materials recovered from secondary materials such as slab zinc, alloys, dusts, and compounds are comparable in quality to primary products. Zinc in brass is the principal form of secondary recovery, although secondary slab zinc has risen substantially over the last few years because it has been the principal zinc product of electric arc furnace (EAF) dust recycling. Impure zinc oxide products and zinc-bearing slags are sometimes used as trace element additives in fertilizers and animal feeds. About 10% of the domestic requirement for zinc is satisfied by old scrap. 

Tetronics A process for treating dusts from electrical arc furnaces for making steel and nonferrous metals. Volatile metals (zinc, lead, cadmium) are recovered, and residual slag is nontoxic and suitable for landfill. The dusts, mixed with coal dust and a flux, are fed to a furnace heated by a plasma gun. The metal oxides present are selectively reduced and the vapors of zinc, lead, and cadmium are condensed in a modified Imperial Smelting furnace. Developed by Tetronics Research Development Company, United Kingdom, and first commercialized for steel dusts at Florida Steel, Jackson, TN, in 1989. Seven plants were operating in several countries in 1992. 

Electric furnaces, 12 286-318 76 144, 145. See also Electric arc furnace (EAF) Fuel-fired furnaces applications for, 12 315-316 arc furnaces, 12 297-306 classification of, 12 286 economic aspects of, 12 313-314 health and safety factors related to, 12 314 induction furnaces, 12 307-313 in phosphorus manufacture, 19 8-11 resistance furnaces, 12 287-297 for secondary slags, 14 759-760 Electric furnace steelmaking processes,... 

Tin is produced from oxide by heating at high temperatures with carbon. Small amounts of limestone and sand are added to coal for this reduction and to promote removal of impurities. Primary smelting is carried out in a rever-baratory furnace at a temperature between 1,200 to 1,300°C. Electric arc furnaces also are used. The molten tin collected at the bottom is cast into slabs. The slags are resmelted at a higher temperature, up to 1,480°, in the same type of furnaces to recover more tin that is combined as silicates. 

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