Slag fuming conventional furnace

The first commercial installation of the standard slag fuming furnace was at the Asarco, East Helena lead smelter in Montana in 1927, and this furnace design has subsequently been applied at a number of other major lead smelters. Copper smelter slags rich in zinc are also processed in conventional slag turners such as at Boliden s Ronnskar smelter in Sweden, and at the Hin Flon smelter of Hudson Bay Mining and Smelting Company. 

Details of operating conventional slag fuming furnaces are given in Table 8.2. 

Representative conventional slag fuming furnaces (Grant, 2004). 

As an alternative to the conventional slag fuming furnace, a top submerged lance slag bath reactor may be used for zinc fuming. In this process fuel as gas, oil or pulverised coal is injected with oxygen... 

For a reactor containing 1 m slag depth, the slag contained is approximately 3 t/m of cross-section and the zinc depletion rate is thus of the order of 0.121 of zinc fumed per hour per square metre of furnace cross-section. This represents a crude indication of reactor capacity only, as gas flow rates are also a major determining parameter and can differ significantly from the conventional slag fumer in relation to bath cross-sectional area. 

An important development in concrete mix design has been the addition of so-called supplementary cementitious materials. Two classifications apply to these compoimds Pozzolans, such as fly ash and silica fume, react with the cement hydration products, notably calcium hydroxide hydraulic materials, such as granulated blast furnace slag, undergo direct hydration reactions. As these materials are of lower cost than conventional cement and essentially represent environmental waste products, there are obvious incentives for blending them in concrete mixes. As pointed out by Hansson, these materials can improve the strength and durability of concrete, with the important proviso that the concrete is cured adequately. 

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