Slag, modelling

Equation (S.21) is normally used in metallic systems for substitutional phases such as liquid, b.c.c., f.c.c., etc. It can also be used to a limited extent for ceramic systems and useful predictions can be found in the case of quasi-binary and quasi-temary oxide systems (Kaufman and Nesor 1978). However, for phases such as interstitial solutions, ordered intermetallics, ceramic compounds, slags, ionic liquids and aqueous solutions, simple substitutional models are generally not adequate and more appropriate models will be discussed in Sections 5.4 and 5.5. 

To obtain a better understanding of the process, calculations were performed by Dinsdale et al. (1988) and Taylor and Dinsdale (1990) for a pre-fused matte of Ni3S2, CU2S and FeS, heated to around 1270 C with an equivalent amount of oxide slag, and with O being blown into the matte. Calculations from the model system Cu-Fe-Ni-S-O are presented in Fig. 10.78 which shows the comparison between calculated and experimental values of the Fe/S partitioning in the matte as a function of SO2 levels. 

In terms of more conventional modelling it is surprising to find that there is still incompatibility between databases that handle complex metallic materials and slags. Sound databases exist for both separately but as yet there is no major integrated database that can handle the very important area of overlap. In terms of a total materials modelling capability it is clearly of benefit to have one self-consistent database rather than a series of separate ones to span a greater range of applications. 

The observed metal phosphate phases agree with thermodynamic models of the ash system described here. These phases control leaching in pH-stat systems and are present after aggressive leaching designed to remove available or leachable fractions. These phases are also similar to ones observed in soil, sediment, smelter dust, industrial wastewater, and slag systems. 

Wittsiepe J, Schrey P, Hack A, Selenka F, Wilhelm M (2001) Comparison of different digestive tract models for estimating bioaccessibility of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) from red slag Kieselrot . Int J Hyg Environ Health, 203 ... 

A model for transient simulation of radial and axial composition and temperature profiles In pressurized dry ash and slagging moving bed gasifiers Is described. The model Is based on mass and energy balances, thermodynamics, and kinetic and transport rate processes. Particle and gas temperatures are taken to be equal. Computation Is done using orthogonal collocation In the radial variable and exponential collocation In time, with numerical Integration In the axial direction. 

Modeling the slag and scale formation in energy installations. 

Shamansky, V. A., "Thermodynamic Modeling of Slag Formation on the Heating Surfaces of Boiler Units". ISEM SO RAN, Irkutsk (2004). (Preprint Afo 2. 70 p. (in Russian)). 

These four component systems, designated as Simplified "Western" slags in Table II, are relatively well behaved in terms of alkali vaporization and are useful model systems for sub-bituminous basic coal slags. The data have been cast in analytical form, as summarized in Table II. 

The last part of ionic electrochemistry, ionics, is about pure electrolytes. A few decades back this electrochemistry would have been all about high-temperature liquids (liquid common salt at 850 °C was the role model). However, this has changed, and the temperatures for eliminating the solvent have deaeased considerably. Some molten salts are now room temperature liquids. At the other end of the temperature scale are the molten silicates, where large polyanions predominate. These are important not only in the steel industry, where molten silicate mixtures form blast furnace slags, but also in the corresponding frozen liquids, the glasses. 

The model considered 17 components in the solids stream water, hydrogen, nitrogen, oxygen, carbon, sulfur, ash, slag, clinker, water(vs), hydrogen(vs), carbon dioxide(vs), carbon monoxide(vs), methane(vs), hydrogen sulfide(vs), ammonia(vs), tar(vs),... 

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