Furnace slag

Calcium. Calcium is the fifth most abundant element in the earth s cmst. There is no foreseeable lack of this resource as it is virtually unlimited. Primary sources of calcium are lime materials and gypsum, generally classified as soil amendments (see Calcium compounds). Among the more important calcium amendments are blast furnace slag, calcitic limestone, gypsum, hydrated lime, and precipitated lime. Fertilizers that carry calcium are calcium cyanamide, calcium nitrate, phosphate rock, and superphosphates. In addition, there are several organic carriers of calcium. Calcium is widely distributed in nature as calcium carbonate, chalk, marble, gypsum, fluorspar, phosphate rock, and other rocks and minerals. 

Flash furnace slag containing 20—40% Pb is reduced in an electric furnace using coal injection. Discard slags have 1—3% Pb and CaO FeO Si02 in the ratio of 0.8 1.0 1.0. 

Insulation. Impure sdiceous limestone and blast-furnace slag are the main raw materials for making rock-wool insulation bats and peUets (see Insulation, thermal). 

The high temperatures in the MHD combustion system mean that no complex organic compounds should be present in the combustion products. Gas chromatograph/mass spectrometer analysis of radiant furnace slag and ESP/baghouse composite, down to the part per biUion level, confirms this behef (53). With respect to inorganic priority pollutants, except for mercury, concentrations in MHD-derived fly-ash are expected to be lower than from conventional coal-fired plants. More complete discussion of this topic can be found in References 53 and 63. 

Blended hydraulic cements are used to conserve energy. They are intimate and uniform blends of tine materials such as Pordand cement, ground blast furnace slag, dy ash, and other po22olans, ie, tine, reactive sUica sources. ASTM C595 Hsts five classes or types. 

Type IS Pordand cement and blast furnace slag cement... 

CaO(from limestone) + Si02 CaSi03(blast furnace slag)... 

Fig. 2. Cement 2ones in the CaO—AI2O2—Si02 system (5) where B represents basic blast-furnace slag D, cement compositions which dust on cooling E, compositions showing no tendency to set G, aluminous cement and PC, Pordand cement.

It is the presence of a large amount of FeO in the lead-zinc furnace slag which produces a liquid at 1550 K, compared with the higher melting, virtually iron-free, slag in the odrer furnace. 

Zinc Zinc is processed very similarly to copper and lead. The zinc is bound in the ore as ZnS, sphalerite. Zinc is also obtained as an impurity from lead smelting, in which it is recovered from the blast furnace slag. 

Hochofen, m. blast furnace, -anlage, /. blastfurnace plant, -betrieb, m. blast-furnace operation. gas, n. blast-furnace gas. -guss, m. blastfurnace cast iron, -koks, m. blastfurnace coke, metallurgical coke, -schlacke, /, blast-furnace slag, -schmelze, /, blastfurnace smelting, -verfahren, n. blastfurnace process. 

Slag wool A mineral wool produced from molten furnace slag. 

Furnace slag cement High service temperatures [1128]... 

A furnace slag cement slurry can have a density of 1500 to 1600 kg/m. A combination of silica flour and furnace slag may be used to achieve service temperatures exceeding 200° C [670]. A gas may be suitable as a foaming agent [358]. 

O. G. Benge and W. W. Webster. Evaluation of blast furnace slag slurries for oilfield application. In Proceedings Volume, pages 169-180. lADC/SPE Drilling Conf (Dallas, TX, 2/15-2/18), 1994. 

K. M. Cowan and A. H. Hale. High temperature well cementing with low grade blast furnace slag. Patent US 5379840, 1995. 

K. M. Cowan and T. R. Smith. Application of drilling fluids to cement conversion with blast furnace slag in Canada. In Proceedings Volume, number 93-601. CADE/CAODC Spring Drilling Conf (Calgary, Canada, 4/14- /16) Proc, 1993. 

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