Slags values

Thus, for each slag, values for m and b can be derived from the experimental viscosity data which uniquely define the linear portion of the viscosity/temperature curve by means of Equation 5. The process then becomes one of correlating the variables m and b with some particular property of the slag. 

Continuous casting slags. These slags have the approximate composition (CaO = SiO = 35% Al-O, = 7% Na O 4-15 and CaF 5-8 ). Olusanya - has reported that the absorption coefficients lie in the range (0.5 - 5 cm ) and thus could be appreciable in these slags. Values of were obtained for ten glassy-slags by Tay r and... 

Blast furnace slags. Values of k Mve been reported by Ischenko —and by Vargaftik and Oleschuk for temperatures in the range (200-1000 °C). The values given are lower than those reported for other slags, which is presumably due to the high porosity of the samples used by these workers. 

Flux additions are set to provide a slag with an Fe0 Si02 ratio of 2 1 and an FeO CaO ratio of 5 1. Higher levels of CaO will increase the activity of PbO and hence will aid subsequent reduction, but this will be offset by the increased volume of slag and greater lead loss at the same final lead in slag value. 

Slags are also removed from the liquation ketde periodically. When chloride slags are formed these are cast into chunks and transferred to a wet plant for leaching to remove chlorides and treatment of the metallic residue. If borax slags are employed, metal values in the slag are recovered by further pyrometaHurgical treatment. 

The recovery of vanadium from these slags is of commercial interest because of the depletion of easily accessible ores and the comparatively low concentrations (ranging from less than 100 ppm to 500 ppm) of vanadium in natural deposits (147,148). In the LILCO appHcations the total ash contained up to 36% 20 (147). Vanadium is of value in the manufacture of high strength steels and specialized titanium alloys used in the aerospace industry (148,149). Magnesium vanadates allow the recovery of vanadium as a significant by-product of fuel use by electric utiUties (see Recycling, nonferrous LffiTALS). 

Metallurgy includes not only the treatment of cmde ore and scrap, but also the processing of intermediates, ie, concentrates, and wastes, such as, slags, tailings, etc, for contained metal values. The various areas and subdisciplines comprising metallurgy may be summarized as follows ... 

Al, respectively, and (-) represent phase transitions in the siUcon in equiUbrium with the Si02 CaO—AI2O2 slag. The numbers represent values in wt... 

As in die case of die diffusion properties, die viscous properties of die molten salts and slags, which play an important role in die movement of bulk phases, are also very stiiicture-seiisitive, and will be refeiTed to in specific examples. For example, die viscosity of liquid silicates are in die range 1-100 poise. The viscosities of molten metals are very similar from one metal to anodier, but die numerical value is usually in die range 1-10 centipoise. This range should be compared widi die familiar case of water at room temperature, which has a viscosity of one centipoise. An empirical relationship which has been proposed for die temperature dependence of die viscosity of liquids as an AiTlienius expression is... 

The comparison of the magnitude of the two resistances clearly indicates whether tire metal or the slag mass transfer is rate-determining. A value for the ratio of the boundary layer thicknesses can be obtained from the Sherwood number, which is related to the Reynolds number and the Schmidt number, defined by... 

Of these terms tlrose involving iron and calcium can be compared as an exatrrple of the exchatrge under ironmaking conditions. Experimental values for tire conesponding equilibria between gas and slag yield values of the sulphide capacities... 

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... 

A certain amount of iron oxide is present in the alumina slag and a certain amount of aluminum is present in the as-reduced iron. Assuming Raoult s law, an aluminum content of 1 wt-% in iron will correspond to A 0.02. The value of aFeG is then 6 10 4. Even a trace of aluminum dissolved in liquid iron results in a practically complete reduction of iron oxide from the slag phase. The assumption that the product phases are pure iron metal and alumina slag thus holds. 

The major limitations attendant to the use of sodium in tetrachloride reduction are the necessity to maintain the temperature of the highly exothermic reduction reaction at values between 801 and 883 °C, and the larger volume of the slag generated because of the monovalency of sodium. Another difficulty pertains to the handling of highly reactive liquid sodium. 

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