Alkali bearing minerals

The alkali-bearing minerals found in the blast furnace include kalio-philite-nepheline, leucite, plagioclase, and alkali carbonates [40-44], Kaliophilite was the dominant reaction product on the inside surface of the lining and in the joints between brick. The formation of this compound is accompanied by about a 45% volume increase. No kaliophilite, however, formed in the interior of the brick except in the carbon-disintegration zones. 

Van Vlack [42] observed that the bosh region contained alkalies in excess of the requirements of kaliophilite and nepheline. This excess did not result in the formation of alumino-silicate or silicate minerals of higher alkali content but was present as alkali carbonates. The carbonates formed toward the end of the furnace campaign from the free alkali deposited in the bosh lining. For the particular furnace examined, Van Vlack determined that alkali-bearing minerals were present only where porosity and proximity of the surface permitted expansion. Therefore, the presence of alkalies did not prove seriously detrimental in the bosh and... 

Feldspars have no sharp melting-point, but soften between 1140° and 1280°C. Within limits, they lower considerably the softening-point of any aluminosilicate (e.g. a clay) to which they are added, the amount of which depends to a first approximation, on the number of equivalents of NagO, KgO or CaO that have been added (Table 18) The fluxing-power of alkali-bearing minerals therefore depends on the molecular proportion of Na O, CaO or K O they contain. 

The mineral types familiar in sediments and sedimentary rocks are present micas, mica-like phases, fully expandable phases and mixed layered series. In a sense, celadonite mica is isolated from dioctahedral mica by a multiphase zone where montmorillonite is stable with a feldspar and mica. It is evident that the only way to. produce celadonite mica under high potassium concentrations is by having a proper bulk composition toward that of celadonite. The possibility of producing celadonite in a potassium deficient system, i.e., where montmorillonite coexists with a non-alkali bearing phase, has not yet been studied experimentally. 

We will consider only two parageneses or facies of the system relevant to sepiolite-palygorskite minerals that where these minerals are stable and that just above their stability (Figure 42). This is estimated provisionally to be somewhat below 80°C. This temperature is justified through comparison with the observed stability (rv/100°C) of natural aluminous, alkali-bearing montmorillonite, which accompanies sepiolite-... 

AJA/WOO] Aja, S. U., Wood, S. A., Williams-Jones, A. E., The solubility of some alkali-bearing Zr minerals in hydrothermal conditions. Mater. Res. Soc. Symp. Proc., 432, (1997), 69-74. Cited on page 223. 

Now we might consider what is in fact the common clay mineralogy of sandstones. Shelton (1964), Bucke and Mankin (1971) find it to be most often dominated by kaolinite. This mineral although hydrous, is conspicuous by its lack of alkalis. Thus one could suspect that alkali activity in pore solutions of sandstones is, or was, frequently low, lower at any rate than adjacent mica-bearing shales. Laboratory studies by Hanshaw and Coplen (1973) and Khareka and Berry (1973) would give a plausible explanation for such a phenomenon. If solutions are forced hydrostatically across the argillaceous membrane, ionic species in solution are selectively... 

Della Ventura G, William CT, Cabella R, Oberti R, Caprilli E, Bellatreccia F (1999) Britholite-hellandite intergrowths and associated REE-minerals from the alkali syenitic ejecta of the Vico volcanic complex (Latium, Italy) petrological implications bearing on REE mobility in volcanic systems. Eur J Mineral 11 843-854... 

Like many elements, potassium s chemical symbol seems to bear no relation to its name. In such cases the symbol often derives from the Latin if the Roman Empire used one ofits minerals, as in this case kalium, from which the word alkali derives. The name potassium comes from the word potash, wood ashes from which the salts of K have been recovered from antiquity. From the 7th century BC the Old Testament s Book of Jeremiah 2 22 refers to neter, which is potash. 

Empirical experience with conventional coal-fired power plants has indicated minerals containing alkali metal (Na, K), sulfur- and chlorine-bearing species to be the most aggressive fuel components leading to fire-side or hot corrosion (5). 

Apatite of igneous origin is preferentially associate with alkaline intrusions and carbonatites. Common minerals associated with apatite-bearing alkaline igneous intrusions include nepheline, alkali feldspars, micas, pyroxenes, and amphiboles. Commonly the pyroxenes and amphiboles are Mg- or Fe-iich varieties, and the micas are biotite or phlogopite. 

Dating sulfide minerals is complicated because they lack radioactive elements such as uranium, thorium, and rubidium. However, some contain potassium, e.g., the mineral rasvumite, KFe2S3. Samples of this mineral were collected from an alkali-rich igneous rock at Coyote Peak near Areata, northern CaKfomia, and they gave a date of 26.5 0.5 Ma, while associated phlogopite mica yielded a total release date from Ar/ Ar measurements of 28.3 0.4 Ma. This confirms that potassium-bearing sulfide minerals can be dated on the basis of the radioactive decay scheme... 

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