Oxides aluminates

Alumina. See Aluminum Oxide under Oxides Aluminized Expletives. See Aluminum Containing Explosives... 

From the larger list of binary refractory oxides, aluminate compounds are listed in Table 3 to emphasize that a family of materials that contain one compound with a high melting temperature will tend to form other compounds with high melting temperatures. Within the aluminate family, a number of compounds are formed that might not... 

Ethyleuio oxide preoipitstes many oxides from adutiona of their salts, such at ferric oxide, aluminic oxide, cupric oxide, magnetic oxide, c. 

Zeolites containing phosphorus in the tetrahedral site in the framework have been synthesized. Phosphorus incorporation in a variety of structural types of zeolite frameworks has been achieved analcime, phillipsite, chabazite, Type A zeolite, Type L zeolite, and Type B ( ) zeolite. The syntheses and properties of some of the new aluminosilicophos-phate zeolites are described. The synthesis technique involves gel crystallization where incorporation of phosphorus is accomplished by controlled copolymerization and coprecipitation of all the framework component oxides, aluminate, silicate, and phosphate, into a relatively homogeneous gel phase. Subsequent crystallization of the gel is carried out at temperatures in the region of 80° to 210°C. Proof and mechanism of framework substitution of phosphorus is based on electron microprobe analysis, infrared spectroscopy, and other characterization. 

The Barin tables are far more complete in coverage than any of the sources described above. All of the natural elements and their compounds are included. In addition to the substance types listed in USBM Bull 677, the Barin tables include a large number of ternary oxides - aluminates, arsenates, borates, chromates, molybdates, nitrates, oxy-halides, phosphates, titanates, tungstates, selenates, vanadates, zirconates, etc. - as well as cyanides, hydroxides, complex silicates and inter-metallic compounds. The only substances not included by Barin, for which tables can be found elsewhere, are the ionized-gas species and a limited number of gas species important only at very high temperatures, which are listed in the JANAF tables. For each table Dr. Barin gives references for each of the major thermochemical values employed (enthalpy of formation and entropy at 298 K, and heat capacity). Like the USBM Bulletins, no attempt is made to discuss the choice between conflicting data sources. 

Many studies have demonstrated that at certain critical Fe/Al ratios, Fe and Al ions may coprecipitate, forming short-range-ordered mixed oxides (aluminous ferrihydrites) of different chemical composition, size, nature, solubility, and reactivity (Cornell and Schwertmann, 1996 Colombo and Violante, 1996). 

Nearly all the practical phosphors for three-band fluorescent lamps are either oxides or oxyacid salts (collectively called oxides ), which can be efificiently excited by 254-nm ultraviolet light generated by low-pressure mercmy vapor discharge. Those phosphors include simple oxide, aluminate, phosphate and borate, etc. Simple oxide combined with aluminate phosphors are the most widely phosphors used in three-band fluorescent lamps mainly due to their high emission efiiciency as well as physical and chemical stability. 

Also included here are the secondary oxides (aluminates) calcium aluminate (CaAl204), cobalt aluminate (C0AI2O4), lead aluminate (PbAl204) and hercynite (iron aluminate, Fe Al204). Calcium aluminate (calciiun aluminium oxide) may be a component of the pigment known as Satin white. Cobalt aluminate (cobalt aluminium oxide) is the pigment Cobalt blue. Lead alu-minate is listed by the Colour Index (1971) under Cl 77585. Hercynite has been identified on Minoan painted pottery by Stos-Fertner et al. (1979). Chromium aluminium cobalt oxide is Turkish Green. 

Alpha alumina, 600, 605-607 Alpha parameter. See a parameter Alumina. See Aluminum oxide Aluminate fiber, 863 Aluminoborosilicate fiber, 863 Aluminoslicate ester, 218 fiber, 863... 

AI 150-200 (tetracoord.) 20-80 (pentacoord.) -20-50 (hexacoord.) AICI3 (1 M) Zeolites, molecular sieves, catalysts, Al oxides, aluminates, Al glasses and ceramics... 

Aluminium oxide is a white solid, insoluble in water, with a very high melting point. If heated above red heat, it becomes insoluble in acids and alkalis, and can only be brought into solution by first fusing it with sodium or potassium hydroxide when an aluminate is formed. 

The structure of these solid compounds is not known with certainty but an approximate formula might be NaAlOj.xHjO. Many aluminates occur in minerals, for example the spinels of general formula M (A102)2 where M may be Mg, Zn or Fe these have a mixed oxide structure, i.e. consist essentially of M AF and O ions. 

L. alumen, alum) The ancient Greeks and Romans used alum as an astringent and as a mordant in dyeing. In 1761 de Morveau proposed the name alumine for the base in alum, and Lavoisier, in 1787, thought this to be the oxide of a still undiscovered metal. 

Sillimanite, see Aluminum silicon oxide (1/1) Smithsonite, see Zinc carbonate Soda ash, see Sodium carbonate Spelter, see Zinc metal Sphalerite, see Zinc sulflde Spherocobaltite, see Cobalt(II) carbonate Spinel, see Magnesium aluminate(2—)... 

There are several processes available for the manufacture of cryoHte. The choice is mainly dictated by the cost and quaUty of the available sources of soda, alumina, and fluoriae. Starting materials iaclude sodium aluminate from Bayer s alumina process hydrogen fluoride from kiln gases or aqueous hydrofluoric acid sodium fluoride ammonium bifluoride, fluorosiUcic acid, fluoroboric acid, sodium fluosiUcate, and aluminum fluorosiUcate aluminum oxide, aluminum sulfate, aluminum chloride, alumina hydrate and sodium hydroxide, sodium carbonate, sodium chloride, and sodium aluminate. 

A commercial process which uses hydrothermal leaching on a large scale is the Bayer process for production of aluminum oxide (see Aluminum compounds). This process is used to extract and precipitate high grade alurninum hydroxide (gibbsite [14762-49-3]) from bauxite [1318-16-7] ore. The hydrothermal process step is the extraction step in which concentrated sodium hydroxide is used to form a soluble sodium aluminate complex ... 

In the vapor phase, acetone vapor is passed over a catalyst bed of magnesium aluminate (206), 2iac oxide—bismuth oxide (207), calcium oxide (208), lithium or 2iac-doped mixed magnesia—alumina (209), calcium on alumina (210), or basic mixed-metal oxide catalysts (211—214). Temperatures ranging... 

An emerging electrochemical appHcation of lithium compounds is in molten carbonate fuel ceUs (qv) for high efficiency, low poUuting electrical power generation. The electrolyte for these fuel ceUs is a potassium carbonate—hthium carbonate eutectic contained within a lithium aluminate matrix. The cathode is a Hthiated metal oxide such as lithium nickel oxide. 

The lanthanum phosphate phosphor is usually prepared by starting with a highly purified coprecipitated oxide of lanthanum, cerium, and terbium blended with a slight excess of the stoichiometric amount of diammonium acid phosphate. Unlike the case of the aluminate phosphor, firing is carried out in an only slightly reducing or a neutral atmosphere of nitrogen at a temperature 1000° C. Also this phosphor is typically made with the addition of a flux,... 

There is also a two-step process of chromizing foUowed by aluminizing. Above 900°C the chromizing begins to rediffuse and the protective oxide changes to Al O from Cr202. Aluminum oxide is less volatile than chromium oxide and better for high temperature oxidation resistance above 1000°C. 

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