Aluminosilicates dissolution

Hamilton, J. P., Brantley, S. L., Pantano, C. G., Criscenti, L. J. Kubicki, J. D. 2001. Dissolution of nepheline, jadeite and albite glasses Toward better models for aluminosilicate dissolution. Geochemica et Cosmochimica Acta, 65, 3683-3702. 

Oelkers, E. H., Schott, J. Devidal, J. L. (1994). The effect of aluminum, pH, and chemical affinity on the rates of aluminosilicate dissolution reactions. Geochimica et Cosmochimica Acta, 58, 2011-24. 

The effect of organic ligands on dissolution of feldspar at ambient temperature has been observed by several groups to follow the same order as that observed by Furrer and Stumm (1986) for alumina citrate, oxalate > salicylate, tartrate > aspartate, acetate (Drever and Stillings, 1997). High-temperature studies of aluminosilicate dissolution in the presence of organic acids have also been completed, but are not reviewed here (see, however the review by Oelkers and Schott, 1998). 

A complete description of any groundwater system necessitates consideration of reactions between rock forming minerals and the aqueous phase. This cannot be achieved without accurate thermodynamic properties of both the participating aluminosilicate minerals and aqueous aluminum species. Most computer codes used to calculate the distribution of species in the aqueous phase utilize the "reaction constant" approach as opposed to the "Gibbs free energy minimization" approach (3). In the former, aluminosilicate dissolution constants are usually written in terms of the aqueous aluminum species, Al, which is related to other aqueous aluminum species by appropriate dissociation reactions. 

FIGURE 2.76 (1) Al direct polarization MAS NMR spectra of clay weathering products and fines from the first sonication (2 min) of clay/rhyolite sample and subsequent sonication for (2) 10 min, (3) 2 h, and (4) 10 h. (Adapted from Geochim. Cosmochim. Acta, 72, Washton, N.M., Brantley, S.L., and Mueller, K.T., Probing the molecular-level control of aluminosilicate dissolution A sensitive solid-state NMR proxy for reactive surface area, 5949-5961, 2008, Copyright 2008, with permission from Elsevier.)... 

Several porosity-destroying reactions also characterize this zone. For example, late ferroan carbonate cements are potential reaction products in this zone, and may significantly occlude porosity (Boles 1978). Also, there is a wide variety of aluminosilicate reaction products (e.g., kaolinite, illite, chlorite, and quartz) that can form in this zone as a result of aluminosilicate dissolution. The imbalance between porosity-enhancing or-preserving reac-... 

Clearance to pulmonary lymph nodes will occur at a fractional rate of 0.0001 per day. Dissolution of the deposited particles and absorption of cerium into the systemic circulation will occur at rates that are between the extremes represented by CeCh in CsCl particles and Ce oxide or Ce in fused aluminosilicate particles as given by the functions included in Figure 9. These rates should not be expected to be constant over the entire clearance period and will depend upon the overall composition of the bulk aerosol particles, which indude particle size, amount of stable lanthanide present, acidity, and the solubility of other components of the particles. The accuracy of predicting respiratory tract clearance and internal organ uptake of radiocerium will depend heavily upon adequate determination of the particle solubility characteristics. 

The concentrations of dissolved species in natnral waters depend ultimately on the dissolution of basic rocks-carbonates, silicates and aluminosilicates-induced by the action of weak acids in the water derived from dissolved gases-e.g. H2CO3 derived from CO2. Anions produced in acid-base reactions balance cations produced in dissolution reactions. The charge balance is ... 

The heats of reaction/solution of some reagents as hydrolysis/dissolution takes place can cause substantial elevation in slurry/solution temperatures, particularly at a large scale where heat transfer and radiative cooUng are not nearly as efficient as it is in small laboratory vessels. Other reagents, such as certain sodium alumi-nates and particularly reagents that are not freshly prepared, may need elevated temperatures for full dissolution in water. These hot or very warm solutions can adversely affect early nucleation conditions in some zeoHte syntheses. Hot reagent solutions and mixtures are sometimes cooled prior to their addition to other reagents to better control the early reactions and speciation of aluminosilicate and silicate precursors. 

In Goulded RF, Equilibrium concepts in natural water systems. Adv Chem Ser 67 161-172 Stumm W, Furrer G, Wieland E, Zinder B (1985) The effects of complex-forming ligands on the dissolution of oxides and aluminosilicates In Drever JI (ed) The chemistry of weathering. Reidel, Dordrecht, pp 55-74... 

The kinetic mass transfer model developed to take into consideration the geochemical evolution of the Cigar Lake ore deposit was mainly done by simulating the evolution of the Al-Si system in the Cigar Lake ore deposit system. To this aim the system formed by kaoli-nite, gibbsite and illite as main aluminosilicate solid phases was considered and kinetics for the dissolution-precipitation processes were taken from the open scientific literature (Nagy et al. 

Leturq, G., Berger, G., Advocat, T. Vernaz, E. 1999. Initial and long-term dissolution rates of aluminosilicate glasses enriched with Ti, Zr and Nd. Chemical Geology, 160, 39-62. 

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