Sodium aluminate solution

From the sodium aluminate solution, aluminium hydroxide is precipitated by passing in carbon dioxide ... 

In gel-forming processes, the reactive aluminosibcate gel is first formed into a pellet which reacts with sodium aluminate solution and caustic solution. The 2eobte crysta11i2es in situ within an essentiaby self-bonded pellet, or as a component in an unconverted amorphous matrix. 

Gibbsite usually contains several tenths of a percent of alkaU metal ions the technical product, precipitated from a sodium aluminate solution, contains up to 0.3% Na20 wliich carmot be washed out even using dilute HQ. Several authors (1,2) suggest that these alkaU ions are an essential component of gibbsite structure. 

Determination of lithium as lithium aluminate Discussion. Lithium may be determined as lithium aluminate by precipitation with excess of sodium aluminate solution in the cold, the final pH of the solution being adjusted to 12.6-13.0. The precipitate is washed with water until free from alkali and weighed as 2Li20-5Al203 after heating at 500-550°C. The solubility in water is 0.008 gL-1 at room temperature it is 0.09 gL-1 at pH 12.6. 

AlClj is treated with NaOH (mole ratio 1 6) to yield an aqueous sodium aluminate solution, 1.2 mole MgS04 (in aqueous solution) are added, the precipitate is washed and dried. 

Beja A process for extracting gallium from sodium aluminate solution, as used in the Bayer process, by means of successive carbonations. Developed by Pechiney in 1946. 

Seailles-Dyckerhoff A process for extracting aluminum from clays and other aluminous minerals rich in silica. The ore is calcined with limestone in a rotary kiln. The product is leached with aqueous sodium carbonate, yielding sodium aluminate solution, from which alumina is precipitated by carbon dioxide. Invented by J. C. Seailles and W. R. G. Dyckerhoff in 1938 piloted in Tennessee in 1942, South Carolina in 1945, and Germany during World War II. See also Pedersen. 

Supersaturated sodium aluminate solutions were prepared using an autoclave which was operated at 150 C and about 600 kPA. The hot caustic solution was filtered through three Whatman filter papers of 4 pm pore size under positive pressure. Three litres of the filtered solution was transferred to the crystallizer, maintained at a constant temperature, which was set for a particular run. 

Researchers in the aluminium industry have investigated the solubility of goethite in sodium aluminate and NaOH solutions. Basu (1983) found, using samples of natural goethite, that the equilibrium solubility of goethite in sodium aluminate solution was close to zero at room temperature and increased exponentially as the temperature rose above 100 °C. She also found that the isothermal solubility was greater in 5 M NaOH than in 5 M sodium aluminate solution at 150 °C, for example, [Fej] was 20 and 50 mgL , respectively. 

Basu, P. (1983) Reactions of iron minerals in sodium aluminate solutions. light Metals, 83-97... 

The present study deals with the application of RDF to the sodium aluminosilicate hydrogels, which were formed by mixing, aging and heating of sodium silicate solution with sodium aluminate solution under stirring, in order to produce NaA-zeolite crystal. 

The chemical analyses of raw materials, namely sodium silicate solution and sodium aluminate solution, are as follows ... 

Furthermore conversely, the heated sodium silicate solution was added into the heated sodium aluminate solution. After mixing for 5 minutes, corresponding to sample A, the hydrogel sample was prepared as sample C. 

The production of aluminum actually involves several steps. Bauxite is the ore that contains aluminum oxide (Al Oj) used to produce aluminum. Impurities of iron, sulfur, silicon and other elements are removed from bauxite using the Bayer process to produce purified alumina. The Bayer process, patented in 1887 by Austrian Karl Josef Bayer (1847-1904), involves pulverizing bauxite and treating it with a hot sodium hydroxide solution to produce sodium alu-minate (NaA102). Sodium aluminate is then placed in a reactor in which temperature and pressure can be varied to precipitate out impurities. The sodium aluminate solution is then hydrolyzed to produce purified alumina ... 

Syntheses were run in modified Morey-type autoclaves of 15-ml capacity at autogenous pressure. For mordenite synthesis, the reactants were mixed in a mortar and pestle into a homogeneous mix and loaded into the autoclaves. For zeolite A and X synthesis, separate sodium aluminate solutions and colloidal silica sols were prepared and mixed in the autoclaves. 

A sodium aluminate solution (2.00 moles Al203/liter, 3.40 moles Na20/ liter, density 1.36 grams/ml) produced from hydrargillite was used as the alumina source in each series of tests. Silica was used as sodium silicate solution (5.98 moles Si02/liter, 1.77 moles Na20/liter, density 1.36 grams/ ml) and as solid amorphous silica with different surface areas (Table I). 

The higher the concentration of the caustic soda solution which is present as a liquid phase in addition to the gel (Figure 1, top), the faster the gels precipitated from sodium silicate and sodium aluminate solutions crystallize to form zeolite A. The gels which crystallized from higher NaOH concentrations give finer particles of zeolite A than do those... 

H2O, with x = 0.4 to 14 (synthesis time 2-3 d, temperature 116°C). Silica sol and sodium aluminate solution freshly prepared by dissolving A1 pellets in NaOH were used as Si or A1 sources, respectively. The as-synthesized materials were calcined at 600°C and NH4-exchanged with 0.5 M NH4NO3 at 80°C. Then samples were dried in air or calcined at 450°C to obtain the H-form. 

Derouane et al. (216) studied the influence of pH and the addition of Na+, Cs+, and tetrapropylammonium ion (TPA + ) on 27A1 NMR spectra of sodium silicate/sodium aluminate solutions. At pH <4 only octahedral Al(H20)g+ species were formed and the spectra were not affected by the addition of either cation. At pH7 a very broad resonance was observed at 10-25 ppm, presumably attributable to precipitated six-coordinated polymeric aluminous species. At pH 10.5 a resonance at ca. 80 ppm appeared in the absence of silicate, corresponding to A OH) it broadened on adding TPA+, but narrowed again when Na+ was also added, suggesting that Na + interacts with aluminate species in preference to TP A+. When sodium silicate was added to the solution, a broad line appeared at ca. 55 ppm corresponding... 

Al(01I)4(Il20)2] - The high viscosity of sodium aluminate solutions is explained by hydrogen bonding between these hydrated ions, and between them and water molecules. By reaction of aluminum and its chloride or bromide at high temperature, there is evidence of the existence of monovalent aluminum, Here the aluminum atom is apparently in the sp state, with an electron pair on the side away from the chlorine atom, whereby the single pairs on the two chlorine atoms are shared to form two weak it bonds. 

Titanium-containing materials have been synthesized from strongly alkaline suspensions obtained by mixing TiCU with alkali silicate and sodium aluminate solutions. The gel obtained was homogenized and mixed in an autoclave at... 

Aluminum hydroxide is produced from bauxite. The ore is dissolved in a solution of sodium hydroxide, and aluminum hydroxide is precipitated from the sodium aluminate solution by neutralization (as with carbon dioxide) or by autoprecipitation (Bayer process) (HSDB 1995 Sax and Lewis 1987). 

Unsupported palladium catalysts are often unstable in use at elevated temperatures and/or high hydrogen pressures. Yada et al. obtained a highly stable palladium black by precipitating palladium hydroxide from palladium chloride solution with an aqueous sodium aluminate instead of sodium hydroxide.177 The palladium catalyst obtained by reduction of the palladium hydroxide prepared with a 1M sodium aluminate solution at pH 10, in the same way as described above, kept a high surface area of 139 m2 g 1 even after the reduction at 200°C in a flow of hydrogen, compared to only 2.0 m2 g 1 with the catalyst prepared using a sodium hydroxide solution as precipitant. The thermally stable catalyst was found to contain 13 ppm of sodium and 1400 ppm (0.14%) of aluminum. 

The dry sodium aluminate was first dissolved in 1.7 times its weight of water and then all 50% caustic requirements were added. The sodium silicate solution was diluted with any water requirement not used to dissolve the dry sodium aluminate. Both solutions were heated to the desired reaction temperature, and then the hot sodium aluminate solution was quickly added to the hot sodium silicate solution (less than 30 seconds) with agitation. The mixture was then agitated until the resulting gel broke down to a homogenous, creamy slurry. 

Four additional factors can also contribute to a limited shift in the time required for crystallization. These are the rate at which the sodium aluminate solution is added to the sodium silicate solution (13), anion activation (14, 15, 16), the source of Si02 (17), and the reaction temperature (10). It has been found that the effect of these variables is most pronounced when synthesizing higher Si02/Al203 ratio zeolites, such as X and Y. Their effect on the synthesis of zeolite A is considerably less and sometimes negligible. 

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