Aluminosilicate complexes formation

In the case of the alkali aluminosilicate complexes, NMR, mass spectrometry TGA ceramic yield and ceramic product purity analyses support the formation of simple trimetallic precursors of the type 15. 

A range of aluminosilicate solutions were investigated. The gelation behaviour, the species in solution (as observed by NMR) and the zeolite crystallization products are described. The effect of concentration and type of alkali metal cation present in solution gives information about the formation of aluminosilicate complexes and how they interact, under the influence of the cation, to form an aluminosilicate gel, the precursor to zeolite crystallization. 

During the first restructuration of the silicate or Si-rich aluminosilicate complexes prior to the zeolitic nucleation, the HM++ entities play a structure stabilizing role. By their particular linear shape, they favour the formation of channel systems. Simultaneously, they can also neutralize one AIO2- negative center of... 

If solutions of sodium silicate and aluminate, having the same pH and resistance, are mixed, and if the concentrations are so low that gel formation does not occur, then a considerable increase in conductivity is noted. This must be due to formation of soluble aluminosilicate complexes."""... 

In such complex system as aluminosilicate precursor gels, various lifetime components can appear reflecting material structure. The gel structure is a result of direct interaction of cations with silicate, aluminate and aluminosilicate anions, redistribution of charges and electron density over the system of aluminosiloxane bonds with effect on the formation of different structural units [24],... 

Components of fluidized cracking catalysts (FCC), such as an aluminosilicate gel and a rare-earth (RE) exchanged zeolite Y, have been contaminated with vanadyl naphthenate and the V thus deposited passivated with organotin complexes. Luminescence, electron paramagnetic resonance (EPR) and Mossbauer spectroscopy have been used to monitor V-support interactions. Luminescence results have indicated that the naphthenate decomposes during calcination in air with generation of (V 0)+i ions. After steam-aging, V Og and REVO- formation occurred. In the presence of Sn, Tormation Of vanadium-tin oxide species enhance the zeolite stability in the presence of V-contaminants. 

Application of Surface Complexation Models for External Surfaces The formation of surface charges in the surface complexation model is demonstrated on the example of aluminosilicates. Aluminosilicates have two types of surface sites, aluminol and silanol (van Olphen, 1977). These sites, depending on pH, may form both protonated and deprotonated surface complexes. From the thermodynamic equilibrium point of view, the protonated and deprotonated surface complexes can be characterized by the so-called intrinsic stability constants, considering the surface electric work. For aluminol sites,... 

As noted in Section 3.3.1, the decarbonation of calcite is greatly favoured by intimate mixing with quartz or clay minerals. Under these conditions, much CO2 is lost before any free lime can be detected. The formation of C2S as an early product is well established, but the situation with the calcium aluminate phases is more complex, no one phase being dominant as an initial product (W11). The aluminate or aluminosilicate phases most often reported as early or intermediate products in laboratory experiments with pure chemicals or raw meals have been CA, CjjA, and, less frequently, gehlenite (W12,D6-D8,W13,L8,L9,I6,C9,C10,R10). CjA can form by 850°C (L9,C10) but seems usually to be a later product. Ferrite phase forms readily, and is initially of low Al/Fe ratio (D7,R10). 

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