Aluminum analysis

Gas-flow proportional counter, 55 in aluminum analysis, 217 in comparison with other detectors, 65-67... 

The silica/alumina mole ratios of the zeolites studied were as follows ZSM-5, 62 large crystal ZSM-5, 75 high silica ZSM-5, 1670 ZSM-11, 78 and dealuminized mordenite, 61. Aluminum analysis was by atomic absorption spectroscopy. Zeolite crystallite sizes were generally less than O.ly, except for the large crystal ZSM-5 sample which was larger than in. 

Unreacted excess amines, such as dicyandiamide (Dicy), were also a cause of corrosion in some early epoxy formulations. Dicy decomposes producing ammonia and other reactive amine compounds. The primary and secondary amines, being quite alkaline, react rapidly with aluminum. Analysis of sealed hybrid microcircuits that used Dicy-cured epoxies showed quantities of ammonia as high as 30,000-100,000 ppmv and extensive corrosion in the presence of moisture. Other... 

Kirschbaum BB, Schoolwerth AC (1989) Acute aluminum toxicity associated with oral citrate and aluminum containing antacids. Am J Med Sci 297 9-11 Kostyniak PJ (1983) An electrothermal atomic absorption method for aluminum analysis in plasma identification of sources of contamination in blood sampling procedures. J Anal Toxicol 7 20-23... 

Wagner s solution (phosphate rock analysis) dissolve 25 g citric acid and 1 g salicylic acid in water, and make up to 1 liter. Twenty-five to fifty milliliters of this reagent prevents precipitation of iron and aluminum. 

Noncatalytic Reactions Chemical kinetic methods are not as common for the quantitative analysis of analytes in noncatalytic reactions. Because they lack the enhancement of reaction rate obtained when using a catalyst, noncatalytic methods generally are not used for the determination of analytes at low concentrations. Noncatalytic methods for analyzing inorganic analytes are usually based on a com-plexation reaction. One example was outlined in Example 13.4, in which the concentration of aluminum in serum was determined by the initial rate of formation of its complex with 2-hydroxy-1-naphthaldehyde p-methoxybenzoyl-hydrazone. ° The greatest number of noncatalytic methods, however, are for the quantitative analysis of organic analytes. For example, the insecticide methyl parathion has been determined by measuring its rate of hydrolysis in alkaline solutions. 

Commercial primary magnesium has a typical purity of 99.8%, which is sufficient for most chemical and metallurgical uses. A typical analysis might be expected to show about 0.003% each of aluminum and copper, 0.04% iron, 0.08% manganese, 0.001% nickel, and 0.005% siHcon. Primary magnesium is available in five grades (Table 3). Considerably higher purity can be obtained by distillation. 

The predorninant method for the analysis of alurninum-base alloys is spark source emission spectroscopy. SoHd metal samples are sparked direcdy, simultaneously eroding the metal surface, vaporizing the metal, and exciting the atomic vapor to emit light ia proportion to the amount of material present. Standard spark emission analytical techniques are described in ASTM ElOl, E607, E1251 and E716 (36). A wide variety of weU-characterized soHd reference materials are available from major aluminum producers for instmment caUbration. 

Methods of Chemical and Spectrochemical Analysis of Aluminum" in Ught Metals and TheirMlloys, Technical Committee ISO /TC 79, International Organization for Standardization, Geneva, Switzerland, 1979. 

Commercial Hquid sodium alumiaates are normally analyzed for total alumiaa and for sodium oxide by titration with ethylene diaminetetraacetic acid [60-00-4] (EDTA) or hydrochloric acid. Further analysis iacludes the determiaation of soluble alumiaa, soluble siHca, total iasoluble material, sodium oxide content, and carbon dioxide. Aluminum and sodium can also be determiaed by emission spectroscopy. The total iasoluble material is determiaed by weighing the ignited residue after extraction of the soluble material with sodium hydroxide. The sodium oxide content is determiaed ia a flame photometer by comparison to proper standards. Carbon dioxide is usually determiaed by the amount evolved, as ia the Underwood method. 

Aluminum triformate [7360-53-4] commercially available as a white crystalline powder, appears amorphous under the microscope. Its solubiHty in cold water is very low, rising to nearly 25% in boiling water (pH 3.2). It remains in solution in a highly saturated state. Infared analysis of soHd aluminum... 

Many of the procedures used for technical analysis of aluminum hydroxides are readily available from the major producers of aluminum hydroxides. Phase Composition. Weight loss on ignition (110°—1200°C) can differentiate between pure (34.5% Al(OH)2) ttihydroxides and oxide—hydroxides (15% Al(OH)2). However, distinction between individual ttihydroxides and oxide —hydroxides is not possible and the method is not useful when several phases are present together. X-ray powder diffraction is the most useful method for identifying and roughly quantifying the phase composition of hydroxide products. 

Thermal Analyses. Thermal analysis often complements x-ray data in providing information on phase composition. The thermal behavior of aluminum hydroxides is particularly important in filler type appHcations. 

Ethyltoluene is manufactured by aluminum chloride-cataly2ed alkylation similar to that used for ethylbenzene production. All three isomers are formed. A typical analysis of the reactor effluent is shown in Table 9. After the unconverted toluene and light by-products are removed, the mixture of ethyltoluene isomers and polyethyltoluenes is fractionated to recover the meta and para isomers (bp 161.3 and 162.0°C, respectively) as the overhead product, which typically contains 0.2% or less ortho isomer (bp 165.1°C). This isomer separation is difficult but essential because (9-ethyltoluene undergoes ring closure to form indan and indene in the subsequent dehydrogenation process. These compounds are even more difficult to remove from vinyltoluene, and their presence in the monomer results in inferior polymers. The o-ethyltoluene and polyethyltoluenes are recovered and recycled to the reactor for isomerization and transalkylation to produce more ethyltoluenes. Fina uses a zeoHte-catalyzed vapor-phase alkylation process to produce ethyltoluenes. 

Shipping, analysis, and safety factors are similar to those of ammonium thiocyanate, except that the alkaU thiocyanates are more thermally stable. Sodium thiocyanate is best handled in 316 stainless steel. At room temperature where some iron contamination can be tolerated, type 304 can be used. Aluminum corrodes more rapidly than stainless steel, but some alloys can be used below 60°C. Some but not all mbber equipment is satisfactory. 

Hardness can also be calculated by summation of the individually deterrnined alkaline earths by means of atomic absorption analysis. Basic samples must be acidified, and lanthanum chloride must be added to minimise interferences from phosphate, sulfate, and aluminum. An ion-selective electrode that utilizes ahquid ion exchanger is also available for hardness measurement however, this electrode is susceptible to interferences from other dissolved metal ions. 

Analysis of ms spectta confu ined the potentiometrically obtained speciation. In addition the complex Allmlx)," was identified. Al-mfx chelates are very stable and may increase aluminum solubility. 

X-ray analysis of material scraped from internal surfaces indicated that it was 88% iron, 7% silicon, and 1% each of magnesium, aluminum, chlorine and sulfur. 

---