Slag-Metal Interaction

For instance, post combustion in the headspace of the furnace (i.e., heat transfer to both scrap and flat bath surfaces) and in the slag layer (heat transfer to slag and slag-metal interaction) must be understood and addressed for specific equipment and furnace configurations. Furthermore, the process control mechanisms (vis-a-vis response times and oxygen utilization) and equipment utilized to effect the post combustion are critical to its viability. 

Each value in the hnal column of the table consuiicted above is now divided by 4, which is the number of additions or subuactions made in each column. The results of tlris division show the numerical effects of each variable and the interaction between variables. The value opposite tire second row shows the effect of the temperature, the third shows the effect of the slag phase composition, and, the hfth the effect of the metal composition. The interaction terms then follow the symbols of each row, dre fourth showing the effect of... 

One of the important differences between calciothermic and aluminothermic reduction of oxides concerns the interaction between the reduced metal and the reductant. Calcium does not form stable solid solutions or alloys with the reduced metals calcium contamination in the metal is, therefore, relatively small. Aluminum, on the other hand, readily forms solid solutions with the reduced metals, and the product generally contains appreciable quantities of residual aluminum. This is not a serious problem because in many cases either a certain aluminum content is desired in the reduced metal or the residual aluminum can be effectively removed in post-reduction purification operations. The extent of the contamination of a reduced metal with the reductant can be related to factors such as the reaction temperature, the standard free energy change associated with the reaction, and the slag composition. Let the following generalized reaction be considered ... 

Many reactions encountered in extractive metallurgy involve dilute solutions of one or a number of impurities in the metal, and sometimes the slag phase. Dilute solutions of less than a few atomic per cent content of the impurity usually conform to Henry s law, according to which the activity coefficient of the solute can be taken as constant. However in the complex solutions which usually occur in these reactions, the interactions of the solutes with one another and with the solvent metal change the values of the solute activity coefficients. There are some approximate procedures to make the interaction coefficients in multicomponent liquids calculable using data drawn from binary data. The simplest form of this procedure is the use of the equation deduced by Darken (1950), as a solution of the ternary Gibbs-Duhem equation for a regular ternary solution, A-B-S, where A-B is the binary solvent... 

In Table 13 the interactions of Si3N4 ceramics with common metals are summarised (see also [18, 472, 473]). For application in metallurgy not only the interaction with the metal but also the interaction of oxide slags on the surface of the metals has to be taken into account. At higher temperatures most metal oxides react with the grain boundary phase. For example, V205,... 

Desulfurization of hot iron by addition of calcium carbide leads to formation of a slag containing calcium sulfide and hydroxide as well as substantial amount of iron oxides. This slag is completely different than other metalurgical slags and may be effectively used for treatment of various acidic dr neutral wastewater containing heavy metal cations by hydroxide/sulfide precipitation, and, by removal of several components from wastewater by sorption and other interactions with iron oxides. 

This is consistent with the present results. Not surprisingly, the metal oxide-silica interaction is a major factor in the desulfurization ability of the slag. 

The silicate slag systems are involved in most pyro-metallurgical processes which result in the formation of a number of ferrous and non-ferrous metals (Cu, Ag, Zn, Cd Sn, Pb, Sb, Bi). These systems are oxide- and sulfide-oxide melts, and, therefore, the processes of their interaction with raw materials are dependent on the melt properties (oxidation ability, solubility of metals), and on their oxoacidic properties. Any metallurgical slag contains MgO, CaO, FeO and Si02 as one of main components. The oxidation ability of the slags increases with a rise of their basicity (increase of equilibrium O2-concentration), caused by the following electrochemical process ... 

Slag The nonmetallic product resulting from the interaction of flux and impnrities in the smelting and refining of metals. 

Known reaction thermoc ramics and kinetics show the oxidizer distribution between alloy corrponents at the contact of liquid phases and the external diffusion process are conditioned by the sulphate concentrations in the surface layer of rretal melt and the equilibrium constants for interactions of metals with sulphate. In such cases the oxidation of liquid alloys enables the selective concentration of a target corrponent in one of the phases - slag or alloy. In particular, it has been found experimentally that in processing of iron-tin-arsenic rrelts by sodium and calcium sulphates the rate of oxidation of iron allowed the concentration up to 90% Sn and up to 90% As in alloy with the loss of not less than 60% Fe [3]. For short short... 

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