Silver Facts
>> Friday, January 1, 2010
Silver Facts
Demand for silver is built on three main pillars: industrial uses, photography and jewelry & silverware. Together, these three categories represent more than 95 percent of annual silver consumption.
Sparkling tableware, shining jewelry, and living spaces brightened by silvered mirrors are the obvious contributions of silver to our daily lives. It is, however, the silver behind the scenes that makes our modern world function more efficiently. Inside switches, silver contacts efficiently and safely turn on and off the powerful electric current that flows into our homes, our lamps and our appliances. It is silver under the keys of computer keyboards, behind automobile dashboards, and behind the control panels of washing machines or microwave ovens that switch on or off at the touch of the finger. And inside the 220-volt line circuit breaker boxes in our homes or inside the 75,000-volt circuit breakers in power stations, silver performs safely and steadily to switch on or off our most dependable servant, electric power, throughout our lives.
Silver has been a multifaceted asset throughout history. It was found as a free metal and easily worked into useful shapes and was widely used by early man. The beauty, weight and lack of corrosion made silver a store of value, and hence one of the earliest of metals to be used as a medium of exchange.
The early discovery that water, wine, milk and vinegar stayed pure longer in silver vessels, led to its desirability as a container for long voyages. Herodotus wrote that Cyrus the Great, King of Persia, a man of vision who established a board of health and a medical dispensary for his citizens, had water drawn from a special stream, "boiled, and very many four wheeled wagons drawn by mules carry it in silver vessels, following the king wheresoever he goes at any time."
In more contemporary times, when the first telegrapher tapped out his code in 1832, silver was the electrical contact that made the current flow. Earlier that century, when Joseph Nicephore Niepce created the first photographic image obtained through a camera-like device in 1813, it was silver nitrate that made it possible. Finally, when the German obstetrician, Dr. Carl Crede made his medical breakthrough in 1884 to halt the diseases that caused blindness in generations of children at birth, it was silver that killed the viruses.
Today, modern technology has revealed an even more remarkable range of electrical, mechanical, optical, and medicinal properties that have placed silver as the key metal in many applications.
Silver in the Home
Every time you turn on a microwave oven, dishwasher, clothes washer, or television set, the action activates a switch with silver contacts that completes the required electrical circuit.
Ordinary household switches, which normally carry high electric current for electrical appliances from irons to refrigerators, use silver. Silver is the metal of choice for switch contacts because it does not corrode, which would result in overheating, posting a fire hazard.
Today's electrical appliances are controlled by membrane switch panels, where the contacts are silver. Membrane switch panels are found in microwave ovens, automobiles and under the keys of personal computers. Due to their reliability and wide use, the silver-contact membrane switch market in the U.S. has grown to over $40 million annually. In an increasing trend, millions of on-the-counter and under-the-counter water purifiers are sold each year in the United States to rid drinking water of bacteria, chlorine, trihalomethanes, lead, particulates, and odor. Here silver is used to prevent the buildup of bacteria and algae in the filters. Research has shown that the catalytic action of silver, in concert with oxygen, provides a powerful sanitizer, that virtually eliminates the need for the use of corrosive chlorine.
126 million troy ounces of silver were used worldwide in 2007 for photography. Although a wide variety of technology is available, silver-based photography is expected to dominate the market for the foreseeable future due to its superior definition and low cost. Silver halide is the material that records what is to be seen in the photograph. As little as 4 photons of light activate silver halides which amplify that incident light by a factor of one billion times. In today's photography, silver halides are coupled with dyes that bring the color of the world around us into a permanent record.
Everyone is accustomed to silvered mirrors. What is new is invisible silver, a transparent coating of silver on double pane thermal windows. This coating not only rejects the hot summer sun, but also reflects internal house heat inward. A new double layer of silver on glass marketed as "low E squared" is sweeping the window market as it reflects away almost 95% of the hot rays of the sun, creating a new level of household energy savings.
Sterling silver has always been traditional tableware because of its sparkling reflectivity, its artistic heritage, and its bactericidal properties. Similarly, silver jewelry owes its long popularity to its reflective beauty and it workability into creative shapes. Worldwide use of silver for these markets amounts to over 163 million troy ounces in 2007.
Watches, clocks, and calculators today are battery driven; for these, the silver battery is the power source of choice. The silver battery provides the higher voltages and long life required for quartz watches. In fact, over 1.5 billion silver oxide-zinc batteries are supplied to world markets yearly, including miniature-sized batteries for watches, cameras and small electronic devices, and larger batteries for tools and commercial portable TV cameras.
Samsung has integrated its Nano Silver Health System to refrigerators where it is used in trays, filters and tubing to kill bacteria and the odors they produce, and in air conditioners, where it is used in surfaces that touch water from condensation. The Silver Nano Health System relies on the dispersal of a colloidal silver solution of sub-microscopic (1~100nano meter) size that can easily penetrate cell walls. When these silver nano particles come into contact with bacteria and viruses they disrupt their structure and inhibit cell growth.
As part of its own growing interest in silver in appliances, Samsung's competitor LG Electronics has introduced to the Middle East market its 'TV refrigerator,' which allows people to enjoy music, movies, satellite broadcasting and cable TV in the kitchen, through a small TV placed on the appliance door, according to K.H. Kim, President of LG Electronics Middle East and Africa. "Users also have the option to order food and groceries from home shopping channels," he added. Equipped with a multi-aperture flow cooling system, which stops heat from the TV from reaching the refrigerator, the unit uses 'Bio Silver' and 'Bio Shield,' LG's brand of nano silver technology to provide anti-bacterial protection.
Silver in Technology
NASA's Magellan spacecraft, on its four year scientific mission, gave scientists their clearest look ever at the surface of Venus. 24,171 silver-coated quartz tiles protected the spacecraft from overheating under twice the solar radiation experienced orbiting the earth, plus the extra heat reflected by the Venusian clouds. The protection afforded by these tiles allowed the sophisticated electronics to work flawlessly, mapping the surface of the planet and its gravity fields with unprecedented detail.
Silver imparts special properties to aluminum alloys. The addition of silver to aluminum has provided the strongest cast aluminum alloy known, now used to advantage in aircraft such as the Air Force C17 transport and in the Army's Apache helicopter. A new silver-lithium-aluminum alloy is the strongest wrought aluminum alloy known. It has been used on several of the NASA space shuttle missions.
Silver's use as a gasket material in the chemical process is due to its chemical inactivity even under powerfully oxidizing conditions of the Space Shuttle engine.
Silver has also long been used to braze materials together. Silver's advantageous alloying and wetting properties are especially useful to hermetically seal together the components of electron power tubes such as the radar tubes now being installed at airports to warn pilots of deadly wind shear.
Silver has a unique affinity for oxygen. This property is critical to high temperature superconductors, which will revolutionize the transmission and storage of electrical power and the efficiency of motors and most other electrical equipment. In this application, silver not only prevents the loss of oxygen, but also acts as a source of nascent oxygen, essential to the operation of the superconductor. When silver is sintered with superconducting materials, the silver matrix itself displays superconducting properties.
Silver is also a powerful oxidative catalyst for the chemical process industry. The production of polyester fabrics, hydraulic fluids, engine antifreezes, and most flexible plastics, such as Mylar, is made more efficient by the use of silver.
Silver In the Hospital
In a world concerned with virus and disease, silver is increasingly tapped for its bactericidal properties and used to treat a range of conditions including severe burns.
Since 1884 when the German obstetrician Carl Crede administered a 1% silver nitrate solution to the eyes of newborn infants, virtually eliminating the incidence of gonococcal opthalmia (a disease causing blindness in newborns), silver has been used as an important bactericide. Only in recent times have modern antibiotics replaced such treatment.
Recent research shows that silver also promotes the production of new cells, increasing the rate of healing in wounds and bone. The regeneration of whole areas of lost skin is being accomplished by the use of silver treatment.
Research indicates that silver-based purification systems are effective in disinfecting water. For the home, silver-based water purifiers are becoming increasingly common. Here silver is used to prevent the buildup of bacteria and algae in the filters. Research has also shown that the catalytic action of silver, in concert with oxygen, provides a powerful sanitizer, virtually eliminating the need for chlorine in swimming pools. Polyvalent silver oxide, a highly charged silver, is finding wide application in the treatment of bacterial and viral disease.
William Conrad Roentgen, who discovered of x-rays in 1895, also discovered that the invisible rays served to activate silver halide crystals, a process that revolutionized medical diagnosis.
One out of every seven pairs of prescription eyeglasses sold in the U.S. incorporates silver. Silver halide crystals melted into glass can change the light transmission from 96% to 22% in less than 60 seconds and block at least 97% of the sun's ultraviolet rays. The change is endlessly reversible.
As part of a growing trend in silver-based bandage usage, two wound dressing makers, Curad and Johnson & Johnson, have recently introduced products into this growing field. Beiersdorf USA, maker of Curad bandages, is marketing a line of wound-care products using silver as a natural antibacterial: Curad Silver. The new line uses silver in the wound pad to help protect minor cuts, scrapes, abrasions, lacerations and scalds. Curad Silver Natural Antibacterial Bandages are available as Assorted Bandages, Extra Large Bandages and Active Gel Bandages which promise multi-day holding ability.
For the health care professional market, Johnson & Johnson has introduced their SILVERCEL antimicrobial alginate dressing, providing the protection of silver and the absorption of alginate. Alginate dressings are highly absorbent, biodegradable dressings made from seaweed. They keep wounds moist, which not only promotes healing but limits damage during dressing changes. According to company officials, SILVERCEL can be especially helpful in the healing of chronic, hard-to-heal wounds that may be infected as a result of a high bacterial count. Because of a sustained release of silver ions, the dressing acts as an effective barrier and may help reduce infection.
Silver On The Highway
Every electrical action in a modern car is activated with silver coated contacts. Basic functions such as starting the engine, opening power windows, adjusting power seats and closing a power trunk all require the use of a relay - a low power switch which activates a much higher power switch. A prime example is the silver membrane switch that activates the relay that powers the headlights.
A universal safety feature of every automobile produced in America, and most throughout the world, is the silver-ceramic lines fired into the rear window. The heat generated by these conductive paths is sufficient to clear the rear window of frost and ice.
Silver in Industry
Electric power drives the world's industry; its distribution depends upon silver contacts in switches and circuit breakers for efficient control. Silver is used in switches from 3 volts at less than 1 ampere to massive switches and circuit breakers which make and break 500,000 volts at 15,000 amperes. In the latter contacts, the silver is combined with tungsten, molybdenum, or other refractory metals.
Silver contacts in membrane switch panels are now standard in control panels for machinery, chemical industry processes, railway traffic controls and elevator call buttons, to name a few.
Silver oxide / zinc batteries, which have twice the electrical capacity of lead-acid batteries of the same size, have long found extensive use by television crews carrying portable battery packs, in aircraft, and in submersibles where weight is critical. Silver has long been known for its unrivaled performance at high temperatures; it is the only battery, for instance, that can provide reliable power for instrumentation at the high temperatures found at the bottom of oil wells.
Radiography, the use of photographic film to record the internal condition of materials, including stainless steel castings, is the major non-destructive evaluation technique for the discovery of structural fatigue and flaws.
Silver as a Store of Value
Silver has been used as a medium of exchange since ancient times (see Genesis 23:16). It was not until the reign of Croesus (560-546 B.C.), king of Lydia (in Asia Minor), that silver was stamped as official coinage.
Throughout history, silver coins were, and still are in many places, essential for internal and international trade. The Spanish reales (also containing 0.8 oz.. silver), minted in Mexico and Peru, were used throughout the Americas for generations. And nearly 400 million of the 1780-dated Austrian Maria Theresa thalers (containing 0.8 oz. silver) have been struck over the past two hundred years to serve as trade coins in Europe and Asia.
In 1792, Alexander Hamilton, then the U.S. Secretary of the Treasury, proposed the adoption of a gold and silver based monetary system. Silver remained in circulating U.S. coins until the supply of silver could not meet the demand for coins and the face value of the coin fell below it's bullion, or meltdown value. The U.S. government eliminated silver from quarters and dimes in 1965 and half dollars were reduced to 40%. In the U.S. today, silver is used only in bullion, commemorative and proof coins. Mexico is the only country currently using silver in it's circulating coinage.
During the past decade, the United States, Canada and Mexico began issuing pure silver coins with nominal face values sold at a small premium over their bullion value (not their face value). In 1982, Mexico began minting a 999-fine (99.9% pure)silver Libertad ranging in weight from 1/20 oz. of a ounce to 5 ounces. Over 20 million of the coins have been sold. The U.S. Mint issues a 999-fine Silver Eagle bullion coin (a one ounce bullion coin with a face value of $1). Over 165 million have been sold since 1986. The Royal Canadian Mint issues a 5 dollar 9999-fine silver bullion coin, the silver Maple Leaf. Over 13 million have been sold since 1986. Australia issues a 5-dollar, 1 ounce 999 fine silver bullion coin, the Kookaburra. Over 8 million have been sold since 1990.
source : http://www.silverinstitute.org/
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