Aluminates Properties

Anhydrous aluminum triduotide, A1F., is a white crystalline soHd. Physical properties are Hsted ia Table 2. Aluminum duotide is spatingly soluble ia water (0.4%) and iasoluble ia dilute mineral acids as well as organic acids at ambient temperatures, but when heated with concentrated sulfuric acid, HF is hberated, and with strong alkah solutions, aluminates are formed. A1F. is slowly attacked by fused alkahes with the formation of soluble metal duotides and aluminate. A series of double salts with the duotides of many metals and with ammonium ion can be made by precipitation or by soHd-state reactions. 

Refined calcined alumina is commonly used in combination with high purity limestone [1317-65-3] to produce high purity calcium aluminate cement (CAC). The manufacture, properties, and appHcations of CAC from bauxite limestone, as weU as high purity CAC, has been described (104). High purity CAC sinters readily in gas-fired rotary kiln calcinations at 1600 —1700 K. CAC reactions are considered practically complete when content of free CaO is less than 0.15% andloss on ignition is less than 0.5% at 1373 K. 

Portland cement is classified as a hydrauHc cement, ie, it sets or cures in the presence of water. The term Portland comes from its inventor, Joseph Aspdin, who in 1824 obtained a patent for the combination of materials referred to today as Portland cement. He named it after a grayish colored, natural limestone quarried on the Isle of Portland, which his cured mixture resembled. Other types of hydrauHc cements based on calcium materials were known for many centuries before this, going back to Roman times. Portland cement is not an exact composition but rather a range of compositions, which obtain the desired final properties. The compounds that make up Portland cements are calcium siHcates, calcium aluminates, and calcium aluminoferrites (see ). 

Analogously, pyrazolyl-aluminate and -indate ligands have been prepared <75JCS(D)749) and their chelating properties evaluated with cobalt, nickel, copper and zinc. Gallyl derivatives of pyrazoles and indazoles have been extensively studied by Storr and Trotter e.g. 75CJC2944) who determined several X-ray structures of these compounds. These derivatives exist in the solid state as dimers, such as (212) and (288). A NMR study in acetone solution showed the existence of a slow equilibrium between the dimer (212) and two identical tautomers (289) and (290) (Section 4.04.1.5.1) (81JOM(215)157). 

This section considers a number of extremely important structure types in which A1 combines with one or more other metals to form a mixed oxide phase. The most significant of these from both a theoretical and an industrial viewpoint are spinel (MgAl204) and related compounds, Na- -alumina (NaAlnOi ) and related phases, and tricalcium aluminate (Ca3Al20g) which is a major constituent of Portland cement. Each of these compounds raises points of fundamental importance in solid-state chemistry and each possesses properties of crucial significance to... 

Tetracalcium aluminoferrite (4CaO Al O, FeOj) has little effect on the physical properties of the cement. For high-sulfate-resistant (HSR) cements, API specifications require that the sum of the tetracalcium aluminoferrite content plus twice the tricalcium aluminate may not exceed a maximum of 24%. 

The majority of metals and alloys available depend for their resistance to corrosion on the properties of an oxide film or corrosion product which is formed initially by the corrosion process. In many cases the protectiveness of the oxide film is determined by its stability in aqueous solutions in a specific pH range, either chemically dissolving to form aquocations at lower pH values or complex anions (aluminate, ferroate, plumbate, zincate, etc.) at higher pH values (Fig. 2.22). An important property of the chemical is therefore the pH value that it develops when dissolved in water. For many materials and many chemicals this is the overriding factor and in many cases... 

Coburn, K. G., Aluminized Steel.Its Properties and Uses , Metallurgia, Manchr., 60, 17 (1959)... 

Hughes, M. L., Hot Dipped Aluminized Steel Its Preparation, Properties and Uses , Sheet Metal Industry, 33, 87 (1956)... 

Enhanced anti-corrosion properties are also reportedly achieved by mill additions of lithium titanate, lithium aluminate or magnesium titanate to the host glass frit . 

Materials formed by acid-base reactions between calcium aluminate compounds and phosphate-containing solutions yield high-strength, low-permeability, C02-resistant cements when cured in hydrothermal environments. The addition of hollow aluminosilicate microspheres to the uncured matrix constituents yields slurries with densities as low as approximately 1200 kg/m, which cure to produce materials with properties meeting the criteria for well cementing. These formulations also exhibit low rates of carbona-tion. The cementing formulations are pumpable at temperatures up to 150° C. 

Dutta DP, Ghildiyal R, Tyagi AK (2009) Luminescent properties of doped zinc aluminate and zinc gallate white light emitting nanophosphors prepared via sonochemical method. J Phys Chem C 113(39) 16954-16961... 

Aluminate cement, 2 415-416 Aluminate ions, silica sols and, 22 394s Aluminates, 2 273-279 analysis, 2 275-276 chemical reactions, 2 273-274 dispersants, 8 710t economic aspects, 2 275 health and safety factors, 2 276 manufacture, 2 274-275 physical properties of, 2 273-274 uses of, 2 276-277 Alumina trihydrate (ATH), 2 274 in synthetic fillers, 11 314-315 Alumina whisker reinforcement, 5 574t Alumina xerogels, X-ray diffraction of, 23 78... 

Cobalt alloys, 7 219-226. See also Cobalt high temperature alloys for orthopedic devices, 3 728 selenium and metallurgy of, 22 98 Cobalt alloy T-800, 7 223 properties, 7 223t CobaltCII) aluminate, uses, 7 241t Cobalt aluminate blue spinel, formula and DCMA number, 7 348t Cobalt Aluminate Blue, pigment for plastics, 7 370t... 

Tetrabromophthalic anhydride physical properties of, 4 357t Tetrabromophthalic anhydride/diol physical properties of, 4 357t Tetrabutylammonium bromide (TBAB), 2 550t, 76 557-558, 566 Tetrabutylphosphonium hydroxide, 22 573 Tetrabutyltin, toxicity of, 24 831 Tetrabutylurea, 2 550t Tetracalcium aluminate,... 

Molten Carbonate Fuel Cell The electrolyte in the MCFC is a mixture of lithium/potassium or lithium/sodium carbonates, retained in a ceramic matrix of lithium aluminate. The carbonate salts melt at about 773 K (932°F), allowing the cell to be operated in the 873 to 973 K (1112 to 1292°F) range. Platinum is no longer needed as an electrocatalyst because the reactions are fast at these temperatures. The anode in MCFCs is porous nickel metal with a few percent of chromium or aluminum to improve the mechanical properties. The cathode material is hthium-doped nickel oxide. 

When HNF or ADN particles are mixed with a GAP copolymer containing aluminum particles, HNF-GAP and ADN-GAP composite propellants are formed, respectively. A higher theoretical specific impulse is obtained as compared to those of aluminized AP-HTPB composite propellants.However, the ballistic properties of ADN, HNIW, and HNF composite propellants, such as pressure exponent, temperature sensitivity, combustion instability, and mechanical properties, still need to be improved if they are to be used as rocket propellants. 

Fey, M.V. Dixon, J.B. (1981) Synthesis and properties of poorly crystalline hydrated aluminous goethites. Clays Clay Min. 29 91-100... 

Wells, M.A. Gilkes, R.J. Anand, R.R. (1989) The formation of corundum and aluminous hematite by the thermal dehydroxylation of aluminous goethite. Clay Min. 24 513-530 Wells, M.A. Gilkes, R.J. Fitzpatrick, R.W. (2001) Properties and acid dissolution of metal-substituted hematites. Clays Clay Min. 49 60-72... 

Table 3.4 Comparison of the properties of alkaline earth aluminate and zinc sulfide phosphorescent pigments...

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