Aluminum solubilities

Analysis of ms spectta confu ined the potentiometrically obtained speciation. In addition the complex Allmlx)," was identified. Al-mfx chelates are very stable and may increase aluminum solubility. 

To demonstrate nonuniqueness, we pose here three problems in geochemical modeling that each have two physically realistic solutions. In the first example, based on data from an aluminum solubility experiment, we assume equilibrium with an alumina mineral to fix the pH of a fluid of otherwise known composition. Setting pH by mineral equilibrium is a widespread practice in modeling the chemistry of... 

Allyl glycldyl ether Allyl propyl disulfide alpha-Alumlna Aluminum alkyls Aluminum metal and oxide Aluminum pyro powders Aluminum soluble salts Aluminum welding fumes 4-Aminodlphenyl 2-Aminopyrldlne Amilrole Ammonia... 

With these kinetic factors in mind, it is still of interest to attempt to get some idea of the possible soluble species and their relationship to aluminum solubility. The data for polymeric aluminum hydrolysis products are those for 50°C. reported by Biedermann (2), who has described the two reactions... 

Lawrence GB, David MB. 1997. Response of aluminum solubility to elevated nitrification in soil of a red spruce stand in eastern Maine. Environ Sci Technol 31 825-830. 

Berggren D. and Mulder J. (1995) The role of organic matter in controlling aluminum solubility in acid mineral soils. Geochim. Cosmochim. Acta 59, 4167-4180. 

Properties White, crystalline solid. Mp 171-172C, bp 219-220C (10 mm Hg), pH (0.1M aqueous solution) 10..6, corrosive to copper, brass, aluminum. Solubility in water 80 g/100 cc (20C). Combustible. 

ALUMINUM SOLUBILITY IN SOILS 5.2a. The Chemistry of Aluminum Hydrolysis... 

Figure 6.15. Solubility lines of possibly stable mineral phases controlling silica and aluminum solubility in acid soils. Actual data points for soil solutions from five different soil horizons are plotted on the pH-) pAI-pSifOH) axis system. Open symbols represent data that were not corrected for soluble polymeric forms of alumina and silica. (From M. C. Johnson and M. B. McBride. 1991. Solubility of aluminum and silicon in acidified spodosols. In R. j. Wright et al. (eds.), Plant-Soil Interactions at Low pH. Dordrecht, Netherlands Kluwer.)...

Figure 6.16. Solubility lines of potentially stable mineral phases controlling silica and aluminum solubility in acid soils. The montmorillonite lines represent the Belie Fourche clay at two different pH values, assuming constant activity, Fe activity controlled by hematite, and Na" as the exchange cation, (Adapted from D. Rai and J. A. Kittrick. 1989. Mineral equilibria and the soil system. In J. B. Dixon and S. B. Weed (eds.). Minerals in Soil Environments. Madison, WIs. Soil Science Society of America.)...

Aluminum hydrolysis reactions arc particularly sensitive to pH and temperature, and to the concentrations of other ligands that might compete with OH in complex formation. The most important inorganic competitor is F (2). Certain organic ligands also can form strong complexes with aluminum (3). Hydrolysis reactions of aluminum also arc influenced by sulfate, and hydroxysulfate solids may control aluminum solubility in acidic solutions (4). 

This paper presents results of some open-system laboratory experiments in which aluminum hydrolysis behavior was studied in detail between pH 4.75 and 5.20, at 10°, 25°, and 35°C. Results arc compared with those of our earlier work and that of others on the hydrolysis of aluminum in dilute solutions below the pH of minimum aluminum solubility. 

Aluminum (soluble salts and alkyls, as Al) Formula CAS RTECS IDLH N.D. 

Figure 10.6 Aluminum solubility as a function of pH, calculated with PHREEQC.

If, in the previous example, the amount of added base is increased (m > 2.5), the aluminum solubility limit is exceeded and a precipitate spontaneously forms. The driving force for this process is a function of the supersaturation, 5, which is the... 

The reactor employed aluminum electrodes supplied by DC power. Chemical oxygen demand (COD), color, conductivity, pH and turbidity were monitored during the process. Aluminum dissolved at the anode, with water electrolyzed at the cathode to produce aluminum hydroxide and hydrogen gas. These reactions and hydroxide precipitation resulted in changes in solution pH during the process. Aluminum solubility was affected by solution pH, which was found to affect COD and color removal. 

The solid points were single phase at 900 °C, the open points had two phases, and open triangles divided into three segments contained three phases at 900 °C, an ordered orthorhombic phase with Cmcm symmetry lies between 25 and 28 at.% Al for Nb contents of 15 to 30 at.%. The phase had an orderd B2 (csCI structure) crystal structure for compositions near the aluminum solubility limit for this phase (approximately 13-15 at.% Al). Disagreement between the p phase boundary compositions and pj, tie-line compositions suggested that equilibration of the p, phase was not achieved in 600 hours at 900 °C over the 10 to 12 at.% Al composition range between the p and O phases. 

Aluminum Soluble in ferrite, also forms nitrides Added to nitriding steels to restrict nitride formation on surface layers... 

At near-neutral pH, aluminum is preferentially complexed by hydroxide, total aluminum solubility is very low, and organic-aluminum complexes are not favored. At this pH, however, organic-silica complexes are more favored, silica is mobilized, and silicate and quartz dissolution rate is accelerated. Organic-acid concentration, however, must be much higher than for the equivalent mobilization of aluminum because of the weaker silica -organic-acid interaction. In a near-neutral pH, organic-rich system, silica is mobilized from the silicate surface with the released aluminum unstable with... 

Coagulation and Flocculation The coagulants most frequently used for membrane plant source water conditioning are ferric salts (ferric sulfate and ferric chloride). Aluminum salts (such as alum or polyaluminum chloride) are rarely used because it is difficult to maintain aluminum concentrations at low levels in the filtered water and in the dissolved form because aluminum solubility is very pH dependent. 

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