Silver production

Mexico, the world s leading producer of silver since the Spanish conquest, obtains virtually its entire silver production from lead—2inc mines in the central cordillera. Mexico retained its dominance in silver production until the discovery of the Comstock Lode in Nevada in 1859. Discoveries in Colorado, Ari2ona, and Montana placed the United States as the world s top silver producer from 1871 until 1900. As these mines played out, Mexico s vast resources returned it to its former position of dominance. 

Mine Production of Silver. World production of silver by region is given in Table 3. Some 900,000 metric tons are estimated to have been mined since early times. By the year 1500 world mine production was about 50 t/yr. In 1992 world production exceeded 14,900 metric tons. EoUowing the breakup of tfie Soviet Union, previously undisclosed data showed that the USSR led wodd silver production during 1979—1980 at about 1550 metric tons. During the early 1990s the production in this region exceeded 2000 t/yr. 

U.S. silver production from 1985 to 1994 averaged 1588 t/yr. Less than one quarter of this output comes from silver mine districts, however. About half is as by-product of gold mines about one quarter comes from copper and lead—2inc mines. The silver production in Mexico from 1985 to 1994 averaged 2256 t/yr, and Pern, at the southern extremity of the cordillera, where silver is a by-product of copper and lead—2inc mines, averaged 1810 t/yr. 

There are four primary silver production facilities in the U.S. Of these, two discharge wastewaters. Wastes containing silver include materials from photography, the arts, electrical components, industry, and miscellaneous sources. These wastes are processed by a wide variety of techniques to recover the silver.2 Because the process is highly specific for the type of waste, no attempt to discuss the various processes will be made in this chapter. 

Hess, K., A. Hauptmann, H. Wright, and R. Whallon (1998), Evidence of fourth millennium b.c. silver production at Fatmali-Kalecik, East Anatolia, in Rehren, Th., A. Hauptmann, and J. D. Muhly (eds.), Metallurgica Antiqua (Der Anschnitt, Zeitschrift fur Kultur im Bergbau, Bochum) 8, 57-67. 

Natural silver halogenides, which are secondary ores for silver production, are characterized by intensive luminescence under powerful laser excitation (Fig. 4.67). The main source of the backgroimd liuninescence is the sorption of organic matter. The relatively long decay time of their liuninescence may enable us to lower the short-lived background emission by several orders of magnitude. 

Obviously, silver has some useful medical properties. But could you be convinced that a colloidal solution of silver taken orally can combat chronic fatigue, meningitis, acne, arthritis, high blood pressure, syphilis, shingles, pneumonia, aids, and cancer I hope you couldn t. But that is exactly what some purveyors of colloidal silver products (a very fine suspension of... 

Since so many factors affect the final composition of ancient silver and since their effects on the final composition are virtually unknown, interpretation of any analytical data could be very difficult. However, previous analyses of silver coins, especially those by Kraay and Emeleus (4) and by Gordus (5), have shown that the concentration of at least one element —gold—in silver can be indicative of the silver-bearing ore used. Concentration levels of other noble metals relative to silver, such as iridium, can be expected to remain constant or almost constant during silver production. These elements, like gold, could be used to distinguish silver obtained... 

Since 1951, silver consumption has exceeded its extraction from ore. Secondary silver production involves the recovery of silver from new and old scrap, resulting from silver-containing wastes generated by industry and the consumer. Recycled silver accounted for 40% of U.S. refinery production in 1971 and had increased to 67% by 1974 (Smith and Carson 1977). It was estimated to be 61% and 56% in 1988 and 1989, respectively (The Silver Institute 1990). The estimated world-wide recovery of silver from the photographic industry is about 67% of the total used (The Silver Institute 1988). It has been estimated that 80%, 68%, and 75% of today s annual consumption by the electrical, industrial-alloy, and art industries, respectively, is recycled silver, but these estimates may be high. 

The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the general principles of the present invention have been defined herein specifically to provide an improved colloidal silver product with significant abilities to kill human pathogens both in vivo and in vitro. 

The 10 ppm silver composition of the present invention was tested and found to be both bacteriostatic and bactericidal for all organisms tested. In other studies, this composition was compared to other commercially available colloidal silver products and found to have a superior activity to all other preparations tested (data not shown). The most interesting observation was the broad spectrum that the 10 ppm silver composition possesses. The antimicrobial activity that was observed was fairly constant independent of the particular organism tested. With the exception of Streptococcus faecalis and Streptococcus aureus (which had MIC values of 10 ppm and 5 ppm, respectively), MIC values ranged between 1.25 ppm and 2.5 ppm for both gram... 

The silver product is deposited on to the particles of silver [126,127] or other... 

It has been suggested that some nanocrystalline silver products release a cluster of silver ions and radicals, which are highly antibacterial because of unpaired electrons in outer orbitals. Silver and silver radicals released from these products are reported to act by impairing electron transport, inactivating bacterial DNA, cell membrane damage, and binding and precipitation of insoluble complexes. ... 

Over-the-counter products containing colloidal silver or silver salts have been marketed for use in adults and children for a wide variety of diseases, including AIDS, cancer, tuberculosis, malaria, systemic lupus erythematosus, syphilis, scarlet fever, herpesvirus infections, pneumonia, typhoid, tetanus, and many others. The US Food and Drug Administration has issued a ruling that a colloidal silver product for any medical use will first have to be approved by the FDA under drug application procedures (11). 

Long distillation times and frequent crucible failures made the VIR furnace the bottleneck for silver production in the early days of operation. The main issues dealt with through the commissioning and optimisation of the VIR furnaces were ... 

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