Precursor Manufacture

The term ammonia catalyst commonly refers to the oxidic form consisting of magnetite and oxidic promoters. In fact this is only the catalyst precursor which is 

The superiority of the catalyst manufacturing processes that use a molten iron oxide stage is mainly due to the fact that above 1000 °C in air, magnetite, Fe304, is the thermodynamically stable oxide phase of iron [8], [343]. Magnetite leads to especially efficient catalysts, and its electrical conductivity allows the use of economical electrical melting processes. 

In 1996 the prices of commercial ammonia catalysts were about 2 /lb (7 DM/kg) for oxidic and about 5.5 /lb (20 DM/kg) for prereduced. Therefore, they are among the least expensive catalysts. 

The raw materials — usually, natural magnetite, lime, potash, and alumina — must, as far as possible, be free of catalyst poisons (see Section 3.6.1.5). Many ores have too high a content of free or bound silica, which can be lowered with magnetic separators [344], Melting is accomplished in electrical resistance or induction furnaces (arc furnaces in the past) operating at 1600-2000 °C. The walls of these furnaces should 

Induction furnaces are optimal for the melting operation. Their good temperature control permits accurate adjustment of the degree of oxidation. Since the melt is held in constant turbulent motion by the magnetic field produced in the primary coil, it is well mixed, even for short melt times. In comparison to the most frequently used resistance furnaces, plant cost and power consumption are higher. 

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OleFns and Fatty Alcohols. Alkylbenzyldimethylammonium (ABDM) quatematies are usually prepared from a-olefin or fatty alcohol precursors. Manufacturers that start from the fatty alcohol usually prefer to prepare the intermediate alkyldimethylamine direcdy by using dimethylamine and a catalyst rather than from fatty alkyl chloride. Small volumes of dialkyldimethyl and alkyltrimethyl quatematies in the Cg—range are also manufactured from these precursors (Fig. 4). 

FIGURE 2.52 Typical PAN precursor manufacturing steps based on solution polymerization and wet spinning. 

T. Yamanaka, K. Okada, and K. Takagahara. Polyimide precursor, manufacturing method thereof, and resin composition using polyimide precursor. US Patent 7 189488, assigned to Kaneka Corporation (Osaka, JP), March 13, 2007. 

It is essential to have strict control of the precursor manufacturing process, with effective quality control to give a consistent uniform product to specification. 

Widory et al. [112] discuss the application of bulk carbon, nitrogen, oxygen, and hydrogen isotope ratio measurements to differentiate different groups of explosives (i.e., PETN,TNT, and ammonium nitrate/fuel oil [ANFO]). The authors also discuss the potential to discriminate samples of the same type of explosive where there are differences with respect to precursors, manufacturing processes, or year of manufacture. 

To increase value add and margins, cathode producers are trying to integrate precursor manufacturers. For the same reason, Korean cell manufacturers, which have... 

The air and water emission, waste generations, and pollution were calculated based on data compiled by Franklin Associates from surveys from 17 resin and precursor manufacturers in North America. Other upstream information was provided by Franklin internal database. Fuels and energy databases are from the US LCl database. All calculations followed ISO 14040 and 14044 requirements (Cradle to Gate Life Cycle 2011). 

Frank, E., Hermanutz, K, and Buchmeiser, MR., Caibon Fibers Precursors, Manufacturing, and Properties , Macromolecular Materials and Engineering, 297, 493-501, 2012. 

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