Uncalcined

Isopropyl alcohol can be oxidized by reaction of an a,P-unsaturated aldehyde or ketone at high temperature over metal oxide catalysts (28). In one Shell process for the manufacture of aHyl alcohol, a vapor mixture of isopropyl alcohol and acrolein, which contains two to three moles of alcohol per mole of aldehyde, is passed over a bed of uncalcined magnesium oxide [1309-48-4] and zinc oxide [1314-13-2] at 400°C. The process yields about 77% aHyl alcohol based on acrolein. 

In 1989, 4,689,000 metric tons of uncalcined gypsum was sold or used 3,229,000 metric tons for use in Pordand cement and the remainder for agriculture and miscellaneous uses. About 17,778,000 metric tons of calcined material was used to produce 1.9 million square meters of board products. Over one million square meters of this material was regular board and about 560,000 m was Type X board. 

ESCA Sample Pretreatment. Samples were pelleted and cut to fit into a rectangular depression in an ESCA sample probe similar in design to one used by Hercules (16). The portion of the probe holding the catalyst sample could be withdrawn into an outer cylinder and sealed under an atmosphere of the pretreatment gas. For pretreatment the calcined samples were exposed to a hydrogen flow at one atmosphere and heated to AOO C. After this pretreatment the sanqile was withdrawn into the insertion tube, sealed in the pretreatment gas, inserted into the ESCA, evacuated, and then the ESCA spectra were recorded. A similar procedure was followed for the uncalcined catalysts except that the temperature was first increased in hydrogen flow to SOO C and held at this temperature for 3 to 4 hours the sample was then heated to 400 C and held at this temperature for 18 hours. 

The Re peak, present as a doublet in this catalyst, resembles the one obtained for Re20 on tape. This suggests, if rhenium hydroxides may be eliminated from consideration, that the calcined rhenium catalysts may have some rhenium in a valence state lower than 4-7. However, even reduction at 400 C of the uncalcined Pt-Re sample does not produce an observable amount of Re(0). 

J. J. Fitzgibbon. Use of uncalcined/partially calcined ingredients in the manufacture of sintered pellets useful for gas and oil well proppants. Patent US 4623630, 1986. 

Adsorption of Inorganic Anions on Uncalcined and Calcined LDHs. 204... 

Both uncalcined and calcined LDHs have also been shown to be effective supports for noble metal catalysts [18-25]. For example, palladium supported on Cu/Mg/Al LDHs has been used in the liquid phase oxidation of limonene [24], and on calcined Mg/Al LDHs for the one-pot synthesis of 4-methyl-2-pentanone (methyl isobutyl ketone) from acetone and hydrogen at atmospheric pressure [25]. In the latter case, the performance depends on the interplay between the acid-base and hydrogenation properties. More recently. 

To date, literature references concerning inorganic anions adsorbed by uncalcined and calcined LDHs cover anionic species such as oxoanions (e.g. NOs , S04 , P04 , As04 , Cr04 , Cr207 ) [133-141] and monoatomic anions (e.g. F-, C1-, Br-, r). 

In addition to anionic species, some metal cations can also be removed via adsorption processes with LDH materials. Recently, Lazaridis reported an interesting removal of two anions (P04 , SCN ) and three cations (Cd , Pb ", Ni " ) from aqueous solutions in single batch systems using uncalcined and calcined (773 K) Mg/Al LDH carbonate materials [148]. It was found that the calcined material showed higher sorption capacities than the uncalcined material for all the ions. Since the sorption capacities are relatively high, the author suggested that LDHs could be considered as a potential materials for sorption of both anions and cations in wastewater treatment systems. Seida et al. have also reported the rapid removal of dilute Pb from dilute aqueous solutions by a column packed with a pyroaurite-like Mg/Fe-COs LDH compound over a wide range of space velocity (Sv = 150-800 min" ) [149]. 

Both uncalcined and calcined LDHs have also been used as sorbents for decontamination of radioactive wastewater [150,151]. For example, Toraishi et al. [151] reported the adsorption behavior of lOs" in radioactive waste-water by LDHs with interlayer or NOs" anions. It was found that the... 

Diffused reflectance spectrum of the 7.9 % V205/AIP04-5 sample after calcination at 550°C was drastically different from that of the uncalcined sample (Fig. 6). The sample before calcination showed a broad charge-transfer band at 400-550 nm. However, the sample after calcination showed a charge-transfer band at 270 nm. In a previous study on surface phases of VjOg supported catalysts [23,24], ions in a distorted... 

Ti02 (50%wt) was impregnated by hydrolyzing Ti-butoxide in the presence of uncalcined TS-l(C)/pure-silica ZSM-5, then calcined at 550 °C. 

Fines from petroleum coke are too small to use alone for domestic heating. But petroleum coke fines have been briqueted successfully, and the briquets used as domestic fuel (21, 88). In one instance, briquets made with 5 to 10% of refinery acid sludge as the binder were roasted to 1100° F. The resulting briquets were clean, hard, strong, and smokeless and could be stored or shipped in any weather. Uncalcined briquets tend to soften and deform in hot weather (16). 

The salts formed by the action of acids on calcined and uncalcined lime were shown to be identical in every respect, and the same amount of gas was expelled from chalk whether the chalk be calcined or digested in acids. Further, by weighing the chalk before and after calcination, J. Black found a loss, not a gain in weight. Thus ... 

Preparation of Potassium Hydroxide by the Electrolysis of a Potassium Chloride Solution. Assemble an electrolyzer (see Fig. 130, p. 231). Place small cylinder 2 (8 cm in height and 4 cm in diameter) made from uncalcined clay into 0.5-litre thick-walled beaker 1. Pour a saturated potassium chloride solution into both vessels so that the level of the liquid in them will be the same. Add a few drops of phenolphthalein to the electrolyte. Use carbon rod 4 as the anode and thick iron wire 3 as the cathode. Secure both electrodes with corks in the electrolyzer lid. A d-c source at 10 V is needed for the experiment. After assembling the electrolyzer, switch on the current. What happens in the anode and cathode compartments Write the equations of the reactions. What substances can form in the absence of a diaphragm ... 

Uncalcined Gypsum and Anhydrite. Calcium sulfate, generally in the form of gypsum, is added to Pordand cement (qv) clinker to stop... 

Uncalcined samples show three different wSi-NMR peaks which can be assigned to Q2, Q3 and Q4 silicon species. After calcination Q4 environments are formed at the expense of Q3 and Q2. Figure 3 shows two 29Si-NMR spectra of a sample before and after calcination. 

Figurel shows the XRD patterns of sample A and sample B. Four distinct XRD peaks can be observed for sample A and sample B, except the ill-defined [210] peak of uncalcined sample B. The clear four-peak profiles appearing at low angles show the presence of long-range order mesopores for samples A and B. The structural data show that, upon calcination at 550 °C, the d spacings were contracted due to the removal of surfactant from mesopores.

Si MAS NMR spectra of the uncalcined MCM-41 samples synthesized normally and with TPA+ and Na+ are shown in Fig 4. It was observed that the ratio of Q4/Q3 peaks was higher in samples synthesized with additional cations. The effect was most pronounced with TPA" as the additional cation. The higher Q4/Q3 ratio indicates that the silicate polymerization during the formation of the mesostructure was enhanced by the presence of the additional cations, Upon calcination, the free silanol groups are forced to condense to form Si-O-Si bond and 29Si MAS NMR of the samples showed predominantly Q4 peak. However, these... 

Fig.4 Si MAS NMR spectra of uncalcined MCM-41 samples with different cations (a) no cation, (b) TPA+ and (c) Na+.

A good-quality CeMCM-41 material with Si/Ce=50 was synthesized by hydrothermal method. For the purpose of comparison a pure siliceous MCM-41 was prepared using the same composition without cerium. Thermogravimetric curves for the synthesized uncalcined samples exhibit shape characteristic for the MCM-41-type materials. The specific surface area of CeMCM-41 evaluated from nitrogen adsorption was equal to 850 m2/g, whereas the pore width and mesopore volume of this material were equal to 3.8 nm and 0.8 cm3/g, respectively. In contrast to the pure silica MCM-41, the CeMCM-41 material exhibits medium and strong acid sites as revealed by thermogravimetric studies of n-butylamine thermodesorption. 

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