Aluminate solution

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

Ca.rhona.tlon, GalHum can be extracted by fractional carbonation which consists of treating the aluminate solution with carbon dioxide in several controlled stages. This process is no longer under industrial operation (6). 

Electrolysis. GalHum can be extracted by direct electrolysis of the aluminate solution at a strongly agitated mercury cathode. The recovery from a sodium gallate solution resulting from the carbonation process is another possibiHty. This process is probably no longer operative because of the environmental problems associated with the mercury. 

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. 

Commercial grades of socbum aluminate contain both waters of hycbation and excess socbum hycboxide. In solution, a high pH retards the reversion of socbum aluminate to insoluble aluminum hycboxide. The chemical identity of the soluble species in socbum aluminate solutions has been the focus of much work (1). Solutions of sodium aluminate appear to be totaby ionic. The aluminate ion is monovalent and the predominant species present is deterrnined by the Na20 concentration. The tetrahydroxyaluminate ion [14485-39-3], Al(OH) 4, exists in lower concentrations of caustic dehydration of Al(OH) 4, to the aluminate ion [20653-98-9], A10 2) is postulated at concentrations of Na20 above 25%. The formation of polymeric aluminate ions similar to the positively charged polymeric ions formed by hydrolysis of aluminum at low pH does not seem to occur. Al(OH) 4 has been identified as the predominant ion in dilute aluminate solutions (2). 

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. 

Misra, C. and White, E.T., 1971. Kinetics of aluminium trihydroxide from seeded caustic aluminate solutions. American Institute of Chemical Engineers Symposium Series, 67(110), 53-65. 

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. 

Routinely, AP is used to control corrosion of carbon steel exposed to caustic-sulfide and caustic-aluminate solutions encountered in the pulp and paper and aluminum industries. 

A preformed chitosan-silica composite with 60% weight inorganic part [7] is used as the source of silica for the zeolite synthesis. An alkaline solution of sodium aluminate (Na 2.1 M, Al 1 M) was used in three methods of preparation (A) beads of the chitosan-silica composite were stirred overnight in the aluminate solution, extracted and submitted to a hydrothermal treatment at 80 °C during 48h (B) beads of the chitosan-silica composite were immersed in the aluminate solution and the system underwent a hydrothermal treatment at 80 °C for 48h (C) beads of the chitosan-silica composite were stirred overnight in the aluminate solution, extracted, dried at 80 °C and exposed to water vapour at 80°C during 48h. 

In the X-ray powder diffraction patterns of the composites, the disappearance of the broad band centered at 22 °20, typical of amorphous silica, indicates that the zeolitisation of the mineral fraction of the parent composite was complete. In no diffraction pattern any sign of crystallised chitosan could be found. The two methods in which the silica-polymer beads were extracted from the aluminate solution after impregnation (methods A and C) allowed the formation of the expected zeolite X, with traces of gismondine in the case of the method C. The method B, in which excess aluminate solution was present during the hydrothermal treatment, resulted in the formation of zeolite A. 

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 ... 

---