Albite melting temperature

Some substances such as quartz and feldspars melt as perfect crystals. The rigid coordination requirement of the Si+4 core does not permit these solids to develop a major concentration of vacant lattice sites. Albite melts at 1118° C., but such a crystal loses neither its shape nor its birefringence when held for several hours at a temperature 50° C. higher than it melting point (33). 

Noble gas sorption experiments were performed on albite melts in an internally heated pressure vessel under 0.1 to 5kbar at 750 to 1200C. The temperature dependence of diffusivities was deduced from Knudsen cell rate-heating and fitted to an Arrhenius equation ... 

Let us assume that, at high temperature and ambient pressure, the binary system albite-anorthite (ab-an) is ideal. The temperature T and enthalpy AH( of melting of each component is... 

Manueli and Bernardini [17] proposed an easily fusible mixture consisting of ammonium nitrate, guanidine nitrate and nitroguanidine. According to them such mixtures may be melted at a temperature below 130°C. The explosive Albit, based on Manueli and Bernardini s patent, consisting of six parts of ammonium nitrate, two parts of guanidine nitrate and two parts of nitroguanidine, has been used in Italy. 

Olivine occurs mainly as inclusions in enstatite and is also found in albite, spinel, and troihte (Brearley, 1989). At least three kinds of poly-crystalline clusters appear to have formed separately (i) enstatite-rich units with forsterite inclusions, (ii) coarser versions with albite and olivine inclusions, and (iii) forsterite-anorthite units with no enstatite. Enstatite crystals are intergrowths of ortho- and clinopyroxene and their microstructures indicate cooling from >1,000 °C at -1,000 °Ch Brearley (1989) suggests that the Kakangari matrix formed from amorphous or partly crystalline particles <10 p,m in size that were annealed at 1,100-1,200 °C or possibly higher, and then rapidly cooled in an hour. The chondrules in Kakangari could have formed from similar material that was heated to higher temperatures, partly melted, and quenched at comparable rates, provided that the chondrules acquired lower concentrations when molten. 

The compound albite, Na20 A1203 6SiOz, melts congruently at 1118 3°C. For those compositions in the albite field with a Iiquidus of about 1040°C or less, albite crystallized in a few days at a temperature 50 to 75° below Iiquidus temperatures. To the left of the carnegieite-silica line, a rapid decrease in the viscosity of melts in the albite field occurs. As a result, it is possible to crystallize albite even at temperatures around 750°C. In the albite field toward the system albite-silica, crystallization of albite is very difficult. 

After cleaning the combustor, Run 218 was made. The major goal of this experimental run was to show that agglomeration/ scaling could be minimized over an extended period by adding commercial clay to the DSS feed since clay would be a more economical inhibitor. The clay is believed to react with the alkali salts present in the DSS to form albite or nephalineC5), double alkali salts (Mp-1108 and 1280 C, respectively) which melt above the combustion temperature. The reactions for the clay were assumed to be as follows ... 

A large number of studies have now been reported on the measurement of diffusion coefficients of isotopic species (e g. 0/ 0) in silicates, oxides and carbonates at elevated temperatures and pressures (see Tables 2, 3 and 4 in this study, or Brady 1995). Those of most relevance, geologically, involved the experimental interaction of a mineral (melt, glass) and either pure water, an alkali chloride solution that is in approximate chemical equilibrium with the solid (e.g. albite and NaCl), or a dry gas such as O2 or... 

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