Gibbsite properties

The possible content of hydrated alumina and iron. Hydrated alumina minerals like gibbsite [14762-49-3] Al(OH)2, boehmite [1318-23-6] AlOOH, and diaspore [14457-84-2] AlOOH, occur ia bauxitic clays. Bauxites grade chemically iato hydrated fermgiaous and manganiferous laterites. Hence, finely divided M2O2, usually hydrated, may be a significant constituent of a clay where M may be A1 or Fe. Hydrated colloidal s ica may play a role ia the sHppery and sticky properties of certain clays. 

Mineralogical properties of boehmite, 2 423t of diaspore, 2 423t of gibbsite, 2 423t Mineralogy, 16 601-603 Mineral oil... 

Simple Models. The surface chemical properties of clay minerals may often be interpreted in terms of the surface chemistry of the structural components, that is, sheets of tetrahedral silica, octahedral aluminum oxide (gibbsite) or magnesium hydroxide (brucite). In the discrete site model, the cation exchange framework, held together by lattice or interlayer attraction forces, exposes fixed charges as anionic sites. 

Natural sources of ATH (Gibbsite extracted from Bauxite) and magnesium hydroxide (Brucite) are available but generally have large particle size as a result of grinding operations and contain significant amounts of impurities. In wire and cable applications, finer particles sizes are utilized for higher FOI values, improved mechanical properties, lower brittleness temperatures, and smoother surface characteristics despite the drawback of increased mixture viscosity.75... 

Apps JA, Neil JM, Jun CH (1989) Thermochemical properties of gibbsite, bayerite, boehmite, diaspora, and the aluminate ion between 0 and 350°C. Washington, DC US Nuclear Regulatory Commission (prepared by Lawrence Berkeley Laboratory), p 98... 

Even in the case of a less drastic final step (dehydration as opposed to reduction), Dalmai et al. found that irradiation infiuenced the catalytic properties of the product 182). Aluminum oxide produced from gibbsite, A1(0H)3, by heating at 290-340° was considerably more active in the decomposition of formic acid if the hydroxide had been irradiated in a reactor to 10 nvt or with about 6 X 10 i ev/gm of y-rays. The changes in catalytic activity were accompanied by somewhat complex effects of radiation on the rate of decomposition of the gibbsite 182a). Thus, irradiated samples decomposed more rapidly at low temperatures and less rapidly at high (above 210°) than unirradiated blanks, although the differences were relatively small. 

PZCs/IEPs of aluminum (hydr)oxides are presented in Tables 3.1 through 3.263. PZCs/IEPs of aluminum oxide and of gibbsite are compiled in [773]. Acid-base properties of the Keggin A,3 polymer are discussed in [774],... 

Properties Traces of gibbsite and bayerite, median diameter 160 nm, size distribution available [353]. 

Properties Ignition at 1000°C produced a-AIjO,. The lower the temperature, the stronger the gibbsite lines [250]. 

Calcination of Gibbsite from Prolabo Properties (calcina-... 

Gibbsite from Baker Properties Specific surface area 0.9 mVg [856]. 

Martifin from Martinswerk Properties Gibbsite, hexagonal particles, 2 pm across, diameter-to-thickness ratio 5 1-10 1, <1% of other crystalline aluminum (hydijoxides than gibbsite, BET specific surface area 7.4 m7g, impurities in washed material (mass%) TciO, 0.01, Na2O 0.36, SO, 0.03, organic C 0.007, SiOj 0.01, Cl 0.12,1 O, 0.002 [1168]. 

Properties Gibbsite with 10-12% of bayerite [562], specific surface area 4 m7g [562,1170], SEM images available [1170]. 

C-730 (Probably from Alcoa [1183]) Properties Well-crystallized gibbsite, specific surface area 10 m /g [1183], single point BET specific surface area 7.8 mVg [450]. 

Properties TEM image, FTIR spectra available, the sample heated for 2 h contains boehmite (20%), and gibbsite (a few%) [1128]. 

The solubilities of gibbsite, boehmite and diaspore in alkaline solutions between 20 and 350°C are evaluated and their thermodynamic properties reconciled. The thermodynamic properties of the aluminate ion, Al(OH)4, are derived over the same temperature range and compared with predictions based on the revised Helgeson-Kirkham-Flowers equation of state. Preliminary thermodynamic properties of bayerite and AGf°298 for nordstrandite are also derived from solubility data in alkaline solutions. Log Kg4 values for gibbsite, bayerite, boehmite and diaspore between 0 and 350°C, and thermodynamic data for A1(0H)4 or AIO2, re tabulated for use in distribution-of-species computer codes. 

The CODATA thermodynamic properties for Al" are based in part on log Kso,29s = 7.95 0.44 for gibbsite. Both are higher than those of two recent solubility studies using synthetic gibbsite that was treated to remove adhering foreign material, i.e., log Kso,298 = 7.55 0.055 (13) and 7.74 0.14 (14), respectively. 

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