Extractive industries

The above covers most conventional mixers there is another class of mixers, called pump-mix impellers, where the impeller serves not only to mix the fluids, but also to move the fluids through the extraction stages. These are speciahzed designs, often used in the metals extraction industries. For these types of impellers, a knowledge of the power characteristics for pumping is required in addition to that for mixing. For a more detailed treatment of these special cases, the reader is referred to Lo et al. 

V. R. Negomedzyanov, V. P. Bortsov, V. S. Denisov, V. V. Slepov, and S. S. Volkova. Plugging composition for use in oil and gas extraction industry—contains Portland cement and aluminium-containing additive in form of slag dust waste from aluminium production process. Patent RU 2029067-C, 1995. 

Some metals are extracted in electrolytic cells. In section 11.3, you saw the extraction of sodium from molten sodium chloride in a Downs cell. Other reactive metals, including lithium, beryllium, magnesium, calcium, and radium, are also extracted industrially by the electrolysis of their molten chlorides. 

The European Union passed the Extractive industries waste directive in 2006. The fuii titie of the directive is Directive 2006/21/EC of the European Pariiament and of the Councii on the management of waste from extractive industries and amending Directive 2004/35/EC ... 

Most of the directive deais with how extractive industry waste is to be deait with in the future within Member States. However, one articie addresses iegacy waste faciiities by requiring Member States to draw up an inventory of such faciiities. The text of Articie 20 is ... 

The material used for hydrolysis, because of its lower cost, is the by-product from various wood-using industries. It consists of mill waste from sawmills and woodworking industries in the form of slabs, edgings, shavings, sawdust, cull veneer and trimmings of shredded wood waste from the solvent extraction industry for rosin and of cull wood that may be removed from cut-over wooded areas as a part of a forest management program. 

Potential applications for this technology include the treatment of airstreams contaminated with volatile organic compounds (VOCs) from air stripping, soil vapor extraction, industrial air emissions, and for the cleaning of air in closed environments. PCO is best suited for waste streams with low concentrations of contaminants, and with low to medium flow rates. The AIR-11 process can operate consistently in conditions where flow rates and VOC concentrations are highly variable, even intermittent. 

The ICBG in Suriname is focusing on the identification of products that can be used as the base for small, extractive industries at the community and family level. Through its ethnobotanical research, Cl has been identifying other nontimber forest products such as nuts, oils, resins, fibers, crafts, ornamental plants, and natural insecticides. Potential products will be analyzed in detail to determine their viability as part of a sustainable marketing project. 

Barkotneier Scale—This scale is used essentially in the tanning and tanning-extract industry. Water equals zero. Each scale degree equals a change of 0.001 in specific gravity. The following formula applies ... 

Raked hearth reactors were once extensively used in the metals extraction industries but are now being superseded. 

Caro s acid, an equilibrium mixture of sulfuric acid, water, and peroxymono-sulfuric acid, is used in the metal-extraction industry. It is manufactured by reacting concentrated sulfuric acid with hydrogen peroxide. Caro s acid is a powerful oxidizing agent and decomposes readily. A process was developed to manufacture 1000 kg/day of Caro s acid in a tubular reactor with a volume of 20 ml and a residence time of less than one second, with the product immediately mixed with the solution to be treated (16). 

Metal and metalloid pollutant analysis of environmental matrices may be conducted with several elemental analysis techniques. For analysis to be possible, all matrices, including unfiltered groundwater, leaching procedure extracts, industrial and organic wastes, soils, sludges, and sediments must be digested with acid. Exceptions are... 

Higher market prices for major commodities such as paprika, vanilla, ginger, bay leaves and spice mixtures resulted in an upward value trend by 4.6% from 2003 to 2004, with a stabilized import volume. There was a growing trend towards the trade of processed spices, which fetched higher prices. The increasing demand for value-added processing of spices, such as capsicum and ginger, offers business opportunities for the food and extraction industries in international markets (International Trade Centre, 2006). 

An important natural product for most of us is a fully methylated purine present in tea and coffee— caffeine. Theobromine, the partly methylated version, is present in chocolate, and both caffeine and theobromine act as stimulants. Caffeine is a crystalline substance easily extracted from coffee or tea with organic solvents. It is extracted industrially with liquid CO2 (or if you prefer Nature s natural effervescence ) to make decaffeinated tea and coffee. 

The shift devastated commercial enterprises in the voluntary extraction industry. Sulfur prices embarked on a decline which culminated with spot sulfur prices falling to the 10s per ton in Tampa, FL, and Vancouver, Canada, by mid-2001. In contrast, prices during 1990 were 140/ton and l08/ton, respectively. The primary difference was that, in 2001, the newly developed disparity between voluntary and involuntary volumes of output precluded a curtailment in sulfur output in the face of a dramatic, yet temporary, decline in demand (see Figs 25.5-25.7). The increase in demand following 2001 took prices in Tampa above 65 per long ton during 2003. 

MacArthur-Forrest See Cyanide. J.S. MacArthur is also famous for establishing the radium extraction industry in the UK from 1911. 

Extractive industries include mining of mineral deposits (principally metal-bearing ores and coal deposits), oil and natural gas production, and quarrying for building and roadmaking materials. Poorly operated or abandoned mine sites are often significant sources of water contamination contaminants of particular health concern from these sources include heavy metals, and mineral-processing chemicals, such as cyanide. 

Information about the distribution and nature of extractive industries can often be obtained from government agencies (principally mines departments or geological surveys), geology departments in universities, and specialist research institutes associated with the mining industry. 

The water contaminants of most concern from extractive industries are summarized in the Table 7,1,... 

Table 7.1 Chemical contaminants of extractive industry wastewaters...

Box 7.1 Risk factors - extractive industries Site suitability... 

Extractive industry activities Effects of mining on water quality Risk factor checklist... 

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