Scale Commercial Applications

The bacteria oxidize and break up the copper minerals, the Cu(II) thus formed dissolving in the acidic liquors. The leach solution is collected at the bottom of the dump, at which stage it will contain about 2 g liter of copper. The copper is extracted by treating the liquors with scrap iron (or by electrolysis) and the barren leach solution, which 

In-place leaching can only be applied in geologically favorable cases, that is where the rock is porous to allow the percolation of the leaching 

The principles imderlying this method have been given in Section II. The bacteria oxidize the pyrite present in the ore to give an acidic solution of Fe(III). This oxidizes UO2 to UOl, which dissolves in the acidic leach solution. Thiobacillus ferrooxidans is able to catalyze this reaction directly, but not rapidly enough to compete with oxidation by Fe(III). 

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TABLE 25-46 Full-Scale Commercial Applications of Fluidized Bed Process... 

One of the landmark achievements in the area of enantioselective catalysis has been the development of a large-scale commercial application of the Rh(I)/BINAP-catalyzed asymmetric isomerization of allylic amines to enamines. Unfortunately, methods for the isomerization of other families of olefins have not yet reached a comparable level of sophistication. However, since the early 1990s promising catalyst systems have been described for enantioselective isomerizations of allylic alcohols and aUylic ethers. In view of the utility of catalytic asymmetric olefin isomerization reactions, I have no doubt that the coming years will witness additional exciting progress in the development of highly effective catalysts for these and related substrates. 

Redox polymerizations are usually carried out in aqueous solution, suspension, or emulsion rarely in organic solvents. Their special importance lies in the fact that they proceed at relatively low temperatures with high rates and with the formation of high molecular weight polymers. Furthermore, transfer and branching reactions are relatively unimportant. The first large-scale commercial application of redox polymerization was the production of synthetic rubber from butadiene and styrene (SBR1500) at temperatures below 5 °C (see Example 3-44). 

GEMEP is cnrrently commercially available. The first fnll-scale commercial application of the technology is scheduled for early summer of 1997 on a Region 2 Snperfund site. According to the vendor, GEMEP has the following advantages ... 

Rusmar Inc. offers a family of long-duration foam products. These products are used for odor suppression, control of volatile organic compound (VOC) and semivolatile organic compound (S VOC) emissions, dust control, and promotion of surface water runoff. The vendor has provided information for several full-scale commercial applications of long-duration foam technology. The technology is commercially available currently. 

Besides the pioneering implementations of specific low-dose applications as well as the widely utilized irradiation of spices now, mentioned in Secs. 4.1, 4.2, and 4.9, small-scale commercial application of irradiation to ensure hygienic quality of food, especially those of animal origin, has been carried out in Chile, China, Indonesia, and Thailand in the past two decades. In the recent years, new commercial irradiators including some that are dedicated to food irradiation have been commissioned in Brazil (which plans to add up to 10 facilities in the coming years), China, India, Republic of Korea, Mexico, and Thailand [157]. 

Powder-layer reactors are not appropriate for full-scale commercial applications, however. Loose catalyst powders are generally not compatible with high-flow-rate situations, as the powder may become compressed or dispersed into the airstream, depending on the direction of the airflow. Powder-layers are also a poor choice in situations where the reactor may be subjected to vibrations or sudden shocks, as might be expected in reactors associated with certain mobile... 

Our first experience with hydrocyclones was with pilot plant trials of the Serck-Baker Oilspin developed as a result of an extensive research program conducted at Southampton U. J While these tests, carried out oo the Murchison and Hutton platforms in early 1983, were not an unqualified success, they demonstrated the equipment s potential and enough encouragement for us to commit to die first Mi-scale commercial application of the Vortoil four-t in-one 35-nun (l.4-in. hydrocyclone later that year. 

The first large-scale commercial application of cross-linked enzyme crystals was the use of glucose isomerase CLCs to produce high-fructose com syrup. While this is not a pharmaceutical or a biotechnological application, it is included here because it serves to demonstrate the economic viability of the technology in a very cost-sensitive business. In this application the CLCs were attached to the surface of a polystyrene-cellulose-titanium oxide composite carrier in a ratio of 9 1 carrier enzyme. The catalyst had a half-life of 150 days at 57°C, and 12-18 tons of dry sugar product could be produced per kilogram of enzyme [37],... 

In spite of these enormous efforts, there is still no large-scale commercial application of cellulose graft copolymers. The reasons for this situation and the challenge it represents to cellulose and polymer scientists and engineers will be the subject of this introductory paper. It is convenient to break down such a discussion into the following areas, synthesis, characterization, properties and, finally, applications. The discussion will be mainly devoted to cellulose itself, although grafting to cellulose derivatives has also been actively pursued. 

Leads and fault current-limiters Current leads and fault current-limiters are the first large scale commercial applications of Bi-based HTSs. Current leads significantly improve efficiency of liquid helium-cooled magnets. 

Other routes to acrylonitrile, none of which achieved large-scale commercial application, are acetaldehyde and HCN (56), propionitrile dehydrogenation (57,58), and propylene and nitric oxide (59,60) ... 

The conventional nickel-based catalysts could be modified by adding oxide promoters such as potassium, lanthanam, cerium, and molybdenum in the catalyst formulations. It is believed that the added promoters improve the dispersion of nickel metal on the catalyst surface, thereby reducing the chance of carbon accumulation. Noble metals such as Pd, Pt, Ru, and Ir have been found to be more carbon tolerant as the solubility of carbon is less in these metals.54-57 However, they are more expensive than nickel-based catalyst, and as a consequence, they are less attractive for large-scale commercial applications. Alloying of nickel with other base metals such as Cu, Co, or noble metals such as Au, Pt, and Re has also been found to decrease... 

Although employed, at one time, primarily as a war gas, phosgene is now an important chemical intermediate for the synthesis of a large number of commercial materials. Worldwide, it is used mainly in the manufacture of isocyanates (for urethane polymers and organic intermediates), polycarbonates (for speciality polymers), and monomeric carbonates and chloroformates (largely for the synthesis of pharmaceuticals and pest control chemicals). The established large-scale, commercial applications of phosgene are summarized in Fig. 4.7. 

Pollutants List is solely for research purposes. Currently, only a few of the PAHs generated during petroleum processing are used as raw material for other commercial applications. These include naphthalene, anthracene, phenanthrene, acenaphthene, fluorene, fluoranthene, and pyrene, with naphthalene and anthracene being the only two with large-scale commercial applications. 

This section snmmarizes the experience and learning on several subjects gained dnring more than 20 years of pilot testing and large-scale commercial applications in polymer flooding in China. 

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