Solid and gaseous oxides

Soderberg aluminum reduction cells for simultaneous removal of aluminum oxides, solid and gaseous fluoride, tar mist (condensible hydrocarbons), and SO2,... 

From this point of view, the filter serves not only as separator between the solid and gaseous components of the interaction, but also as a niobium oxide condenser . 

Solid particle-gaseous oxidizer systems have been studied because of applications to propints and expls (Refs 5 14), and hazards due to dust explns (Refs 1,3, 4, 6, 7, 10 15). Strauss (Ref 9) reported on a heterogeneous detonation in a solid particle and gaseous oxidizer mixt the study concerned A1 powder and pure oxygen in a tube. Detonations initiated, by a weak source were obtained in mixts contg 45-60% fuel by mass. Measured characteristics of the detonations agreed with theoretical calcns within about 10%, and detonation pressures of up to 31 atms were observed. With regard to solid particle-air mixts, detonations have not been reported only conditions for expln have been studied (Ref 2)... 

Interesting linear relations were obtained by Golutvin [48] correlating the standard formation enthalpies of solid and gaseous compounds of elements (AH°eq.(g,s), see Equation 44), which are normalized to the oxidation state of the metal ion in this compounds (w) and to the number of metal ions (metal equivalents) in the compounds (eqnwaiXwith the logarithm of the oxidation state of the metal ion in this compounds, see Figure 6. 

PEVD has been applied to deposit auxiliary phases (Na COj, NaNOj and Na SO ) for solid potenfiometric gaseous oxide (CO, NO, and SO ) sensors, as well as a yttria stabilized zirconia (YSZ) ceramic phase to form composite anodes for solid oxide fuel cells. In both cases, the theoretically ideal interfacial microstructures were realized. The performances of these solid state ionic devices improved significantly. Eurthermore, in order to set the foundation for future PEVD applications, a well-defined PEVD system has been studied both thermodynamically and kinetically, indicating that PEVD shows promise for a wide range of technological applications. 

Let us now consider binary oxide MOi g equilibrated with gaseous phase at constant temperature. The process of oxygen exchange between the solid and gaseous phases can be represented by the following reaction ... 

When it is considered that oxidation reactions may be conducted in the presence of various solid and gaseous catalysts, under the influence of electrical discharges, under alpha radiation, etc., it will lie realized that no one theory can be expected to account for the diverse results. Indeed it is reasonable to suppose that the mechanism may be quite different in the different cases. However, in all the methods so far proposed, if any oxygenated compounds at all are formed, aldehydes are present. This would indicate that the aldehyde stage is intermediate in all of the processes. 

Although Crv and CrIV are formed as transient intermediates in the reduction of CrVI solutions, these oxidation states have no stable aqueous chemistry except as peroxo complexes because of their ready disproportionation to Crm and CrVI. Some solid and gaseous compounds do, however, exist. 

As mentioned above, the way in which the KOH acts is very different to that of the other activation reagents. In this case, KOH reacts with the carbon skeleton, producing solid and gaseous products. At the same time a carbon bum-off occurs giving rise to porosity. Experimental evidence shows that hydrogen and metallic potassium are formed during the reaction, as well as CO and CO2 (which come from the carbon skeleton) and potassium oxide. Lillo-Rodenas and coworkers [49] proposed that the chemical reaction involved is ... 

Diesel exhaust is a complex mixture of thousands of chemicals in solid and gaseous forms. This mixture contains gases such as carbon monoxide, carbon dioxide, the oxides of nitrogen (i.e., nitric oxide and nitrogen dioxide), and sulfur dioxide hundreds of different hydrocarbons and diesel particulate matter (DPM). DPM is a mixture of chemical compounds composed of nonvolatile elemental carbon hundreds of different adsorbed or condensed hydrocarbons such as polycycUc aromatic hydrocarbons (PAHs) and nitro PAHs sulfates and trace quantities of metallic compounds. 

The Fire Triangle The well-known/i/ g triangle (see Fig. 26-33) is used to represent the three conditions necessary for a fire (1) fuel, (2) oxygen or other oxidizer (a gaseous oxidizer such as chlorine, a liquid oxidizer such as bromine, or a solid oxidizer such as sodium bro-mate), and (3) heat (energy). 

The chemical identities of the fission products determine their subsequent redistribution, those elements which are in the gaseous state at the temperature of the operation migrating to the cooler exterior of the fuel rods, and die less voltile elements undergoing incorporation in the fuel rod in solid solution. Thus caesium and iodine migrate to the gas fill which sunounds the fuel rod, and elements such as the rare earths and zirconium are accommodated in solid solution in UO2 without significant migration along the fuel rod radius. Strontium and barium oxidize to form separate islands which can be seen under the microscope. 

The solid iron ore is formed into pellets, which are presented to the gas in a vertical shaft containing the pellets in tire form of a packed bed. The reducing gas enters the shaft at the bottom and rises tluough the packed bed reacting to form gaseous oxidation products, CO2 and H2O. The heat required to raise the reactants to a temperature at which the reaction rate is fast enough is usually canied by the inlet gas phase. 

By tire coiTect choice of the metal oxide/carbon ratio in the ingoing burden for the furnace, the alloy which is produced can have a controlled content of carbon, which does not lead to the separation of solid carbides during the reduction reaction. The combination of the carbon electrode, tire gaseous oxides and the foamed slag probably causes tire formation of a plasma region between the electrode aird the slag, and this is responsible for the reduction of elecU ical and audible noise which is found in this operation, in comparison with tire arc melting of scrap iron which is extremely noisy, and which injects unwanted electrical noise into the local electrical distribution network. 

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