Aluminum content

Producing lead—calcium—aluminum alloys is difficult. Calcium and aluminum can be added simultaneously to lead using a calcium (73 wt %)—aluminum (27 wt %) master alloy (11) (see Aluminumand aluminum alloys). Using this method, the calcium and aluminum contents can be precisely controlled. Pressed pellets of metallic aluminum andmetaUic calcium are also used. 

Quantitative aluminum deterrninations in aluminum and aluminum base alloys is rarely done. The aluminum content is generally inferred as the balance after determining alloying additions and tramp elements. When aluminum is present as an alloying component in alternative alloy systems it is commonly deterrnined by some form of spectroscopy (qv) spark source emission, x-ray fluorescence, plasma emission (both inductively coupled and d-c plasmas), or atomic absorption using a nitrous oxide acetylene flame. 

In industrial practice it is generally the aluminum content of alums that is important. Because aluminum sulfate is widely available, other alums are more specialty items and are no longer produced in quantities comparable to those of aluminum sulfate (14). 

High purity 50% ferrosihcon containing <0.1% Al and C is used for production of stainless steel and corded wire for tires, where residual aluminum can cause harm fill alumina-type inclusions. These are also useflil in continuous cast heats, where control of aluminum is necessary. High purity grades of 50 and 75% ferrosihcon containing low levels of aluminum, calcium, and titanium are used for sihcon additions to grain-oriented electrical steels, where low residual aluminum content contributes to the attainment of desired electrical properties, eg, significant reduction of eddy currents. 

Zinc slush-casting alloy compositions are based on the Zn—A1 system. The two commonly used alloys have nominal aluminum contents of 4.75%... 

The product is similar to that obtained by the aliiminothermic process however, the aluminum content is lower and silicon may mn as high as 0.8%. Chromium oxide may also be reduced with carbon at low pressure. 

Assuming that the reaction is close to completion at the hnal temperature, and therefore tlrat Xcr and Xai Oj are close to unity, the residual aluminum content of the metal and the amount of unreduced chromia can be obtained from the equilibrium constant... 

Each of these grades has a minimum aluminum content of 27 percent, expressed as AljOj, and maximum FejOj and soluble contents of 0.75 percent and 0.5 percent, respectively. 

Energy and Products Liberated on the Detonation of Explosives of the Minol Type. Effect of Variation in Aluminum Content (Interim... 

Anon, Minol Mixtures of High Aluminum Content. Improved Blast Performance of Minol Containing 28% Aluminum , ARDE Report 118/44 (Sept 1944) 32) Anon, Studies of... 

Aluminum is the most abundant metallic element in the Earth s crust and, after oxygen and silicon, the third most abundant element (see Fig. 14.1). However, the aluminum content in most minerals is low, and the commercial source of aluminum, bauxite, is a hydrated, impure oxide, Al203-xH20, where x can range from 1 to 3. Bauxite ore, which is red from the iron oxides that it contains (Fig. 14.23), is processed to obtain alumina, A1203, in the Bayer process. In this process, the ore is first treated with aqueous sodium hydroxide, which dissolves the amphoteric alumina as the aluminate ion, Al(OH)4 (aq). Carbon dioxide is then bubbled through the solution to remove OH ions as HCO and to convert some of the aluminate ions into aluminum hydroxide, which precipitates. The aluminum hydroxide is removed and dehydrated to the oxide by heating to 1200°C. 

Hensen EJM, Zhu Q, van Santen RA. 2005. Selective oxidation of benzene to phenol with nitrous oxide over MFI zeolites. 2. On the effect of the iron and aluminum content and the preparation route. J Catal 233 136-146. 

One of the important differences between calciothermic and aluminothermic reduction of oxides concerns the interaction between the reduced metal and the reductant. Calcium does not form stable solid solutions or alloys with the reduced metals calcium contamination in the metal is, therefore, relatively small. Aluminum, on the other hand, readily forms solid solutions with the reduced metals, and the product generally contains appreciable quantities of residual aluminum. This is not a serious problem because in many cases either a certain aluminum content is desired in the reduced metal or the residual aluminum can be effectively removed in post-reduction purification operations. The extent of the contamination of a reduced metal with the reductant can be related to factors such as the reaction temperature, the standard free energy change associated with the reaction, and the slag composition. Let the following generalized reaction be considered ... 

A certain amount of iron oxide is present in the alumina slag and a certain amount of aluminum is present in the as-reduced iron. Assuming Raoult s law, an aluminum content of 1 wt-% in iron will correspond to A 0.02. The value of aFeG is then 6 10 4. Even a trace of aluminum dissolved in liquid iron results in a practically complete reduction of iron oxide from the slag phase. The assumption that the product phases are pure iron metal and alumina slag thus holds. 

Ulcer prophylaxis H2-receptor antagonists Sucralfate Proton pump inhibitors Adjust dose in those with Rl decreased TAC absorption if Rl, caution aluminum content no Rl, caution hypophosphatemia... 

The tetrahedral Al incorporated in mesoporous silica reduces considerably the quantity of amorphous carbon, increasing the MWCNTs selectivity, due to the formation of strong Bronsted acidic sites, which allow a better dispersion of iron metallic clusters. The Fe/Al-MCM41 (10) showed the best results in CNT purity and yield. This indicates that the aluminum content and its tetrahedral structural incorporation play an important role in the CNT syntheses. 

The studied solids exhibit great differences in term of porosity (purely microporous, micro-mesoporous and mesoporous). As it is well known, mesoporosity of USY (CBV series) increases as the aluminum content decreases. Large part of mesoporosity is in the range 2-3.6 nm according to the difference between mesoporous volume obtained by N2 or Hg measurements. Pore size estimation gave similar results whatever the technique. 

The equilibrium, room temperature structure of pure cobalt is hep. The fee structure is stable at high temperatures (422 °C to 1495 °C) and has been retained at room temperature by rapid solidification techniques [101], X-ray diffraction analysis was used to probe the microstructure of bulk Co-Al alloy deposits containing up to 25 a/o Al and prepared from solutions of Co(II) in the 60.0 m/o AlCfi-EtMelmCl melt. Pure Co deposits had the hep structure no fee Co was observed in any of the deposits. The addition of aluminum to the deposit caused a decrease in the deposit grain size and an increase in the hep lattice volume. A further increase in the aluminum content resulted in amorphization of the deposit [44], Because the equilibrium... 

Fig. 12A,B The relation between the aluminum content and the fracture behavior of the SA fiber...

Independent of the ligand system, two different activation methods have been used in performing the propylene polymerization experiments. In both cases, the catalytic activities and molecular weights of the polymers are a sensitive function of the aluminum content provided by the activators. This dependence suggested an additional reversible chain transfer to aluminum when activating with MAO. As lower contents of A1 are provided in the polymerization system in the case of in situ activation with TIBA/borate, the only mechanism occurring is the chain back-skip. Furthermore, the differences in the polymer microstructures prepared with MAO and borate as cocatalysts are reflected. They sustain the proposed reversible chain transfer. 

Epidemiological studies have shown a strong association between the aluminum content of the water used to prepare dialysates and the incidence of dialysis dementia. Reducing water aluminum content below 20 JJ.g/1 appears to prevent the onset of the disease in patients who have just started dialysis. 

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