Slags structure

The silicon map shows the distribution of slag inclusions, while the position of the weld lines can be seen to be marked by boundaries between areas of high and low phosphorus content and by enrichments of nickel and/or arsenic at the weld lines. Higher resolution maps can be made of welds to reveal their fine structure. 

In this process EAF dust, other zinc-bearing wastes, recycled materials, coke or coal, lime, and silica are mixed and fed to a rotary furnace. The zinc and other volatile nonferrous metals in the feed are entrained in the furnace off-gas and are carried from the furnace to an external dust collection system. The resulting oxide (zinc calcine) is a crude zinc-bearing product that is further refined at zinc smelters. A byproduct of the process is a nonhazardous, iron-rich slag that can be used in road construction. Solidification technologies change the physical form of the waste to produce a solid structure in which the contaminant is mechanically trapped. 

Air-cooled blast furnace slag. If the liquid slag is poured into beds and slowly cooled under ambient conditions, a crystalline structure is formed, and a hard, lump slag is generated, which can subsequently be crushed and screened. 

Thermal property is another critical property for furnace slag. Because of their more porous structure, blast furnace slag aggregates have lower thermal conductivities than conventional aggregates. Their insulating value is of particular advantage in applications such as frost tapers (transition treatments in pavement subgrades between frost-susceptible and nonfrost-susceptible soils) or pavement base courses over frost-susceptible soils. 

The iron-carbon solid alloy which results from the solidification of iron blastfurnace metal is saturated with carbon at the metal-slag temperature of about 2000 K, which is subsequently refined by the oxidation of carbon to produce steel containing less than 1 wt% carbon, the level depending on the application. The first solid phases to separate from liquid steel at the eutectic temperature, 1408 K, are the (f.c.c) /-phase Austenite together with cementite, Fe3C, which has an orthorhombic structure, and not the thermodynamically stable carbon phase which is to be expected from the equilibrium diagram. Cementite is thermodynamically unstable with respect to decomposition to iron and carbon from room temperature up to 1130 K... 

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

MMVF are synthetic fibers with glasslike structures. The term usually refers to silicate-based glass fibers, because these compositions form the largest volume of fibers produced. However, in addition to fiberglass and fused silica (Si02), there are other amorphous fibers used in commerce alumina (AI2O3) and silica combinations, rock and slag wool, as well as fibers with nonsilicate compositions such as carbon. Many of these amorphous fibers have proprietary names. 

The raw product obtained by the evaporation of graphite is soot and slag. Next to soluble fullerenes the soot and slag contain other kinds of closed carbon structures, e.g. giant fullerenes [187] and nanotubes [188, 189] the rest is amorphous carbon. Fullerenes can be isolated from the soot either by sublimation or by extraction. The first isolation of fullerenes was achieved by a simple sublimation with a Bunsen... 

The Sonotech Cello pulse combustion system has the same limitations as a nonpulsating burner attached to a combustion device. Preliminary testing of the Sonotech system showed that in order to prevent slag formation, the temperature of the rotary kiln gas should not exceed 1700°F. The system produces considerable noise, which may be controlled by sound insulation. The Sonotech system uses resonant frequency of the incinerator to create pulsations. In an older incinerator, if the sound energy is not properly applied, the Sonotech system could cause structural problems. 

K. Shimoda, Y. Tobu, K. Kanehashi, T. Nemoto and K. Saito, Total understanding of the local structures of an amorphous slag perspective from multi-nuclear ( Si, Al, Mg, and Ca) solid-state NMR. /. Non Cryst. Solids, 2008, 354,1036-1043. 

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