Feldspar uses

Note The data set WATEQ4F.dat uses the name adularia for K-feldspar. Use EQUILIBRIUM PHASES to fix the oxygen concentration to 21 Vol%. Enter quartz with 0 0 under the same key word. While the first zero limits the... 

Tafto, J., Buseck, P. R. (1983). Quantitative study of Al-Si ordering in an orthoclase feldspar using an analytical transmission electron microscope. Amer. Mineral., 68, 944-50. 

I. M., and Lee M. R. (1999) Direct measurement of Ar diffusion profiles in a gem-quality Madagascar K-feldspar using the ultra-violet laser ablation microprobe (UVLAMP). Earth Planet. Sci. Lett. 170, 141-153. 

Discrepancies between reactive and adsorption surface area may also be related to the presence of deep etch pits or pore outcrops which can constitute transport-limited micro-environments for dissolution (Jeschke and Dreybrodt, 2002). Much of the BET surface area for some alkali feldspars used for dissolution in the laboratory has been attributed to grinding-induced microporosity (Hodson et al, 1999), and such pore outcrops are candidates for transport limitation. If such induced surfaces react dilferently than surfaces of weathered samples, then the BET surface area may be an inappropriate parameter to use for extrapolating interface-limited kinetics from laboratory to field (Lee et al, 1998 Brantley and Mellott, 2000 Jeschke and Dreybrodt, 2002) and consideration may need to be given to length and extent of grinding for laboratory samples (Hodson, 1999). It may be more appropriate to use geometric rather than BET surface area to extrapolate kinetics for samples where etch pits or pore outcrops are important contributors to BET surface area (Gautier et al, 2001 Jeschke and Dreybrodt, 2002 Mellott et al, 2002). 

Perry, D.L., L. Tsao, and K.A. Gaugler. 1983. Surface study of HF- and HF/H2SO4-trcated feldspar using Auger electron spectroscopy. Geochim. Cosmochim. Acta 47 1289-1291. 

Thin sections were prepared /or 28 samples following impregnation with blue-dye epoxy resin, and stained for calcite and K-feldspar using alizarin red S and potassium ferrocyanide, respectively. The thin sections were systematically scanned by the senior author to determine rock composition, porosity and textural relationships. 

In ceramics we are often dealing with multicomponent systems such as the ternary quartz, clay, and feldspar used in the formation of porcelains or the binary NiO, AI2O3 that react to form a spinel. Equilibrium, at constant T and P, is reached in these systems when the chemical potential, Pi, of a component is the same in all of the phases in which it is present. The chemical potential, or the partial molar free energy of a component in a given phase, is defined as... 

Johnson, E. Rossman, G.R. (2003). The concentration and speciation of hydrogen in feldspars using FTIR and iR MAS NMR spectroscopy. American Mineralogist, Vol. 88, pp. 901-911... 

Koretsky CM, Svegensky DA, Salisbitry JM, D Aria DM (1997) Detection of smface hydroxyl species on quartz, y-almnina and feldspars using diffuse reflectance infrared spectroscopy. Geochim Cosmochim Acta 61 2193-2210... 

Forking. The separation of a propagating fracture into two or more new fractures at acute angles. See crack branching. Forshammer Feldspar. A Swedish feldspar used as a flux in tableware bodies, to replace DF Stone, compared to which it was higher in alkalis and lower in silica. 

Tinsel. Very thin glass that has been crushed and silvered for use as a decorative material (cf. glass frost). Tirschenreuther Pegmatite. A byproduct of china-clay washing, comprising quartz and feldspar, used in porcelain bodies and in spray-dried prepared bodies. (Hutschenreuther AG, Germany). 

The amounts of feldspar used in common types of pottery bodies are sanitaryware, 25-35% hotel china, 15-35% chemical porcelain, 15-30% electrical porcelain, 30-50% whiteware, 15-30% floor and wall tile, 10-55%. 

The softening range of the body decreases, and refractoriness increases with increased KjO, at the expense of NaO and CaO, in the feldspar used. With semi vitreous bodies which do not contain any CaO, soda feldspar compositions mature slightly sooner than potash feldspar. When hme is added the situation is reversed. The reason lime causes a sharp increase in the fusibUity of potash feldspar but not of soda spar. The glassy content of the body produced with soda feldspar is less viscous than that produced by potash spar, and thus the soda spar bodies deform more readily. 

We briefly described the sandstone cores and sampled each lithology type. For each sample, routine X-ray diffraction analyses and thin sections were made. Thin sections were prepared from rock containing pressure impregnated, blue-dyed, epoxy resin so that pore space would be readily discernable. Thin sections were stained to facilitate recognition of carbonates and K-feldspar using the techniques of Dickson (1966) and Bailey and Stevens (1960), respectively. Point-count analyses were made using a voice recognition system described by Dunn et al. (1985). A minimum of 300 points was counted per thin section. 

Natural feldspars used for the preparation of ceramics are mineral mixtures. Thus, the commercial potassium products can contain between 2.5 and 3.5% of albite mass, whereas anorthite and a small quantity of orthoclase, between 0.5 and 3.2%, are often present in the available sodium feldspars [MAN 94]. They can also be incorporated into the paste in the form of feldspathic sand. When these natural products are heated, mixed and homogenous feldspar is formed. This compoimd. 

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