Silver

Statistics and Information (from U.S.G.S. Mineral Commodity Summaries, 2013):
Silver has been used for thousands of years as ornaments and utensils, for trade, and as the basis for many monetary systems. Of all the metals, pure silver has the whitest color, the highest optical reflectivity, and the highest thermal and electrical conductivity. Also, silver halides are photosensitive. Owing to the above properties, silver has many industrial applications such as in mirrors, electrical and electronic products, and photography, which is the largest single end use of silver. Silver’s catalytic properties make it ideal for use as a catalyst in oxidation reactions; for example, the production of formaldehyde from methanol and air by means of silver screens or crystallites containing a minimum 99.95 weight-percent silver.

The physical properties of silver include ductility, electrical conductivity, malleability, and reflectivity. The demand for silver in industrial applications continues to increase and includes use of silver in bandages for wound care, batteries, brazing and soldering, in catalytic converters in automobiles, in cell phone covers to reduce the spread of bacteria, in clothing to minimize odor, electronics and circuit boards, electroplating, hardening bearings, inks, mirrors, solar cells, water purification, and wood treatment to resist mold. Silver was used for miniature antennas in Radio Frequency Identification Devices (RFIDs) that were used in casino chips, freeway toll transponders, gasoline speed purchase devices, passports, and on packages to keep track of inventory shipments. Mercury and silver, the main components of dental amalgam, are biocides, and their use in amalgam inhibits recurrent decay.

Events, Trends, and Issues:
Industrial demand for silver in photography continued to decline, and in the United States, demand for silver in photography fell to about 550 tons, compared with a high of about 2,000 tons in 2000. Although silver was still used in x-ray films, many hospitals have begun to use digital imaging systems. Approximately 99% of the silver in photographic wastewater may be recycled. Silver demand for use in photographic applications, jewelry, electronic applications, and coins declined; however, the use of silver in brazing alloys and solders and other industrial applications increased slightly. Silver was used as a replacement metal for platinum in catalytic converters in automobiles, and silver was also used as a catalyst in numerous chemical reactions. Silver also was used in clothing to help regulate body heat and to control odor in shoes and in sports and everyday clothing. The use of trace amounts of silver in bandages for wound care and minor skin infections was also increasing.

World silver mine production increased to a new record of 24,000 tons as a result of increased production from mines in China, Kazakhstan, and Mexico, as well as increased recoveries from mines in Indonesia and Peru. Production also increased in Australia because of the start up of the Wonawinta Mine (lead-zinc) in New South Wales and a major expansion for the Mount Isa (copper-lead-zinc), which was processing ore from the newly opened Lady Loretta Mine (copper) in Queensland. In 2012, the Sindesar Khurd Mine (lead-zinc) in India was estimated to have produced 70 tons more of silver than it produced in 2011. Overall, domestic silver production declined, with the temporary closure of Lucky Friday Mine, ID, in January 2012, the leading domestic primary silver mine in 2011. The mine was ordered closed by the Mine Safety and Health Administration after an accident and rock burst at yearend 2011 thatled to a buildup of material in the Silver Shaft, the primary access to Lucky Friday. Production was expected to resume in early 2013. Output also fell atBingham Canyon Mine, UT (copper-molybdenum), at the Mission Complex, AZ (copper-molybdenum), and at the Midas Mine, NV (gold). Some of the output losses were partially offset by production gains at the Rochester Mine (primary silver) and at the Smoky Valley Common Operations (gold), both in Nevada.

World Resources:
Silver was obtained as a byproduct from lead-zinc mines, copper mines, and gold mines, in descending order of production. The polymetallic ore deposits from which silver was recovered account for more than two-thirds of U.S. and world resources of silver. Most recent silver discoveries have been associated with gold occurrences; however, copper and lead-zinc occurrences that contain byproduct silver will continue to account for a significant share of future reserves and resources.

Substitutes:
Digital imaging, film with reduced silver content, silverless black-and-white film, and xerography substitute for silver that has traditionally been used in black-
and-white as well as color printing applications. Surgical pins and plates may be made with tantalum and titanium in place of silver. Stainless steel may be substituted for silver flatware, and germanium added to silver flatware will make it tarnish resistant. Nonsilver batteries may replace silver batteries in some applications. Aluminum and rhodium may be used to replace silver that was traditionally used in mirrors and other reflecting surfaces. Silver may be used to replace more costly metals in catalytic converters for off-road vehicles.