Thermal conductivity of refractories

Fig. 2. Thermal conductivity of refractories where ASF = aluminosiUcate fiber and ZF = 2ii conia fiber. See Table 13 for group classifications (5,25).

Fig. 2. Thermal conductivity of refractory fiber insulations with 96-mg/cm density.

ASTM C201-86, Standard Test Method for Thermal Conductivity of Refractories , Annual Book of ASTM Standards, American Society for Testing and Materials, Philadelphia, PA. 

W. R. Davis, Hot-Wire Method for the Measurement of the Thermal Conductivity of Refractory Materials , in Compendium of Thermophysical Property Measurement Methods, (K. D Maglic, A. Cezairliyan, and V. E. Pelet-sky, eds.), Vol. 1, Plenum Press, NY (1984). 

Thermal conductivity of refractory at average temperature of layer BTU-in/Hr/Ft /°F Log base n... 

A discussion on the thermal conductivity of refractory carbides and nitrides is given in Ch. 4, Sec. 2.4. As can be seen in Table 11.2, the nitrides of Groups IV and V, like the corresponding carbides, can be considered good thermal conductors, reflecting the metallic character of... 

One of the main purposes of the brick lining is to provide thermal protection to the membrane. The protection afforded depends not only on the brick s thickness but also on its thermal conductivity. The thermal conductivity of refractory and carbon brick is generally higher than fireclay type. Table 7.2 provides the minimum brick thickness at various operating temperatures to protect a membrane with a maximum allowable temperature of 250°F/121°C. Table 7.3 provides the K factor (thermal conductivity) of the various corrosion resistant bricks. 

ASTM C201-93 (1998). Standard test method for thermal conductivity of refractories. 

ASTM C202-93(2013). Standard test method fru thermal conductivity of refractory brick. 

The classical heat balance of the reduction cell has not significantly changed for 100 years (Fig. 2.6a). The side lining has no or almost no heat insulation, while the bottom has good thermal insulation. The infiltration of electrolyte through the carbon cathode blocks to the refractory layer increases the thermal conductivity of refractories, but the infiltration increases the thermal conductivity of the heat insulation layer dramatically. The heat flow through the bottom increases. 

A. Eschner, B. Grosskpopf, and P. Jeschke, Experiences with the hot wire method of measurement of thermal conductivity of refractories, Tonind-Ztg, 98(9) 212, 1974. 

There are few measurements of the thermal conductivity of refractory compounds. Williams et al. (24) measured k(T) in TiB2. Radosevich and Williams (25) [see also Williams (26)] measured k in normal and superconducting NbC. In a conventional superconductor, the thermal conductivity decreases on the transition to the superconducting state. The reason is that the electrons in the superconductor cannot transport heat because they would fall into the forbidden energy gap if they lost energy. (A superconductor is not a thermal superconductor, and the Wiedemann-Franz law is not valid.) Contrary to this behavior, Ktot in NbC increased as one passed below T. This can be understood from the dominating role of Kia, which is limited by Tpi,.ei. In the superconducting NbC the phonon-electron interaction becomes weaker and hence Kiat increases. 

The thermal conductivity values have been obtained principally by the steady-state method most of the data have been converted by the authors of the different publications, including the author of the present reference work, to nonporous condition of the specimens, using the fairly reliable extrapolation to zero porosity accordingto Kingery s formula xp yp(l-P), where P is the porosity in fractions of unity [239], However, despite the absence in a number of publications of any reference to the condition of the specimens and their porosity, the author has considered it possible to reproduce the thermal conductivity data given in these publications as tentative values, since information on the thermal conductivity of refractory compounds is extremely scanty. 

F. H. Norton and W. D. KIingerly, The Measurement of Thermal Conductivity of Refractory Materials Technical Progress Report, USAEC Report NYO-601, Massachusetts Institute of Technology, 1952,... 

Thermal conductivity is a measure of the refractory regarding its abiUty to conduct heat from the hot to the cold face when it is exposed to high temperatures. There are three different methods of determining thermal conductivity of refractory materials. ASTM C-210 is the standard method for determining... 

Crowley MS. The effect of high-conductivity gases on the thermal conductivity of refractory concrete linings, Paper no. 64-PET31. ASME Petroleum Mechanical Engineering Conference, Los Angeles, CA, Sept. 20, 1964. 

As mentioned, the thermal conductivity of refractories often changes with temperature, and dense and insulating material types tend to behave differently with changes in temperature. 

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