Potassium aluminosilicate

Type 3A sieves. A crystalline potassium aluminosilicate with a pore size of about 3 Angstroms. This type of molecular sieves is suitable for drying liquids such as acetone, acetonitrile, methanol, ethanol and 2-propanol, and drying gases such as acetylene, carbon dioxide, ammonia, propylene and butadiene. The material is supplied as beads or pellets. 

Blanc A process for extracting alumina from leucite ore (a potassium aluminosilicate) in which the ore is leached with hydrochloric acid, aluminum trichloride is crystallized, and this is calcined to alumina. Invented by G.A. Blanc in 1921 and used in Italy from 1925 to 1943. 

Barrer, R.M. and Baynham, ).W. (1956) The hydrothermal chemistry of the silicates. Part VII synthetic potassium aluminosilicates./. Chem. Soc., 2882-2891. 

Molecular sieve, 3A 200 Light permanent gases Potassium aluminosilicate (zeolite) 20% (mass/mass) water capacity, smaller pore size than 0.5 nm, thus different retention characteristics... 

Figure 2 is a three-dimensional representation of the results and shows the dependence of the gel time on composition for potassium aluminosilicate solutions. Gel times do not depend simply on the concentration of any one component. Rather, a valley of shortest gel times extends almost diagonally across the plot from low-silica, low-alkali, to high-silica, high-alkali compositions. Values to either side of the "valley" are higher. The longest gel times - up to two weeks - occur in solutions of high-silica, low-alkali content. 

Figure 2 Log(gel time) for potassium aluminosilicate solutions. Each dot represents a solution composition from Figure 1.

Figure 3 Log(gel time) of potassium aluminosilicate solutions 1e - 8e prepared by Method 2 of mixing. = normal mixing as in Method 1, = 22% of total alkali added to silicate solution before mixing with aluminate, 44% of total alkali, = 66% of total alkali and 0= 88% of total alkali.

Figure 4 shows the light-scattering curve for nine selected potassium aluminosilicate solutions. Two types of behaviour were apparent. For low-silica solutions, a low, steady amount of scattered light is followed by a sharp increase as the solution becomes cloudy prior to gelling, possibly suggesting a nucleation-and-growth mechanism. There is a direct relation between the persistence of the low value and the observed gel time - the... 

Figure 4 Light scattering curves for potassium aluminosilicate solutions prepared by Method 1 of mixing. All curves are scaled as for solution 1a.

This proved extremely informative. Aluminosilicate complexes were observed in every solution studied. Although the spectra measured are of solutions undergoing change, the time taken to collect the data was generally small compared with the gel time. Figure 5 shows spectra for the nine representative potassium aluminosilicate solutions. A summary of the shifts is given in Table II. 

Figure 7 27Al NMR spectra of potassium aluminosilicate solution 6e prepared by Method 2 of mixing. Acquisition time was 0.067s and the number of scans averaged 6000. All data was collected in 4K and transformed in 32K. Spectrum 1 = normal mixing as in Method 1,2 = 22% of excess alkali added to the silicate soltuion before mixing with aluminate, 3 = 44% of excess alkali, 4 = 66% of excess alkali and 5 = 88% of excess alkali.

Figure 8 27AI NMR spectra of potassium aluminosilicate solution 4b over time. Acquisition time was 0.067s and the number of scans 5000 for each spectrum. All data was collected in 4K and transformed in 32K.

The synthesis of erionite was reported by Zhdanov (11) in 1965. The medium was described as a mixed sodium-potassium aluminosilicate hydrogel at 90°-100°C but further details are not given. Breck and... 

Figure 8.26. A. NMR spectra of a potassium sialate geopolymer after curing at room temperature (upper) and after heating at 1300°C (lower). B. Change of the peak position of potassium polysialate geopolymer as a function of heating temperature. Note the progressive shift in the peak position towards that of the anhydrous potassium aluminosilicates. From Barbosa and...

FIGURE 3.18. Polished section of a large tungsten particle showing several holes in the matrix that formed on polishing these holes were originally filled with potassium aluminosilicates. 

Silicate Minerals in Coal. The silicate minerals, kaolinite and potassium aluminosilicate species together with quartz constitute the bulk of mineral matter in most coals. The approximate amounts of different silicate species of the bituminous coal mineral matter can be estimated from ash analysis. 

Minex. [Unimin SpecialQ Mrnerab] Sodium potassium aluminosilicate fine ground mineral extender. 

In the steam reforming of naphtha, potassium promoters accelerate the reaction of carbon with steam. However, this leads to formation of KOH, which sublimes. In this case, potassium aluminosilicate was successfully used as promoter. In the presence of steam and CO2 it decomposes into K2CO3 and KOH to an extent that is just sufficient to remove the coke that is formed. This prolonged catalyst lifetimes to 4-5 years [T35]. 

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