High-temperature thermal treatment

By chemical vapor deposition from hydrocarbon precursors in the presence of a catalyst followed by high-temperature thermal treatment. 

High-temperature thermal treatment of hazardous waste offers a reduction in volume as well as a conversion of toxic organic constituents to harmless or less harmful forms [1]. However, hazardous metals can neither be generated nor destroyed in the waste thermal process, but they can be transformed both chemically and physically [2]. There is therefore a potential for hazardous metals to emit if they vaporize at high temperatures [3]. Many matals and their salts will form vapors at temperatures reached by flame and post-flame zones of a combustion chamber. When the vapors cool, they condense to form submicron particles, which tend to be relatively difficult to capture in air polution control equipments. These emissions of submicron metallic particles have been identified as one of the greatest health risks associated with waste incineration [4]. 

The improvement of the thermal stability of ceria by introduction of zirconium has been widely studied [8-10] and "estimated" by measuring the surface area of mixed oxides after high temperature thermal treatment. In the case of mixed oxides prepared by co-precipitation for example, an increase of the "preserved" surface area of aged oxides was observed even with the introduction of only 10 at.-% of... 

Dealumination and ultra-stabilization of zeolites through high temperature thermal treatment and hydrothermal treatment. 

Although high-temperature thermal treatment has proven effective, the cost for process implementation historically has been high. As a result, this study focused on evaluation of low-temperature treatment technologies for the explosives-contaminate debris. 

High-temperature thermal treatment will mineralize the explosives contaminants to form mainly C02 and H20. The fate of the explosives contaminants is not as clear in the lower temperature thermal desorption case. Low-temperature thermal treatment involves some decomposition, but volatilization is the main removal mechanism. All of the low-temperature systems provide for methods to capture the volatilized organics from the off-gas. Residuals from the off-gas treatment may be organic liquid and/or spent carbon sorbents. These residuals will require further treatment or disposal. The low-temperature techniques provide good protection of human health and the environment by either destroying the contaminants or concentrating them in a controlled manner for further processing. 

Each type of compound discussed before, by its nature, lends itself to either direct reuse or some degree of treatment prior to reuse. Direct reuse includes utilizing the soil as a raw material for asphalt or concrete. Treatment options range from simple and inexpensive aeration to costly comphcated high temperature thermal treatment. Treatment operations discussed here include aeration, land farming, bioremediation, low-temperature thermal desorption, high temperature thermal treatment, asphalt incorporation, and concrete incorporation. 

High temperature thermal treatment It is similar to low temperature thermal desorption, but is hot enough to thermally destroy volatile and hydrocarbon compounds. The cost of high temperature thermal treatment is, therefore, much more than low-temperature desorption, but the soil is typically completely depleted of volatile and heavy hydrocarbon compounds. PCBs are typically destroyed to 99.99% by this method. The use of the soil after high temperature thermal treatment depends on the original material s quality, as the soil can typically be used as a clean fill. In some cases, it is used as a feed stock for asphalt or concrete. 

In this activation method, water molecules present on the surface of pristine clay react with alkylaluminum compounds to produce MAO oligomers on the clay surface [6, 50, 62, 81, 89]. The modified clay can then be used directly as a polymerization cocatalyst, or impregnated with a catalyst solution prior to polymerization. The high temperature thermal treatment to remove surface-bonded water molecules is not required in this case, albeit it has been used by some researchers [6, 50]. 

Table 1 summarizes some microstructural and electrochemical properties of porous Si anode materials, as pertaining to the second approach mentioned above, collected from the literature published since 2005. Several synthesis methods have been identified for preparing the porous Si anode materials (column 1, Table 1). One of the two most adopted methods is known as the metal-assisted chemical etching (MACE denoted as E in Table 1). The fundamental principle of this method can be found in the handbook chapter Porous Silicon Formation by Metal Nanoparticle Assisted Etching. Figure 2 shows an example of the MACE-derived porous Si particle. The other most adopted method is magnesiothermic reduction (denoted as M in Table 1). In this method (see handbook chapter Porous Silicon Formation by Porous Silica Reduction ), porous Si oxide materials are reduced by magnesium vapor under high-temperature thermal treatment. The porous Si oxide precursors may be synthesized via the conventional sol-gel processes. Porous Si particles with unique pore structures, such as hollow interior and ordered mesoporosity, may be obtained from Si oxides having the same pore structures which are achieved by using proper templates.

The effect of a high-temperature thermal treatment has been analyzed from X-ray diffraction, Raman and photoluminescence experiments on polythiophene samples synthesized from a-bis silylated thiophene monomers [20]. It has been shown that treatment at an elevated temperature of polythiophene led to significant... 

High temperature thermal treatments and isothermal oxidation tests... 

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