Silver: An Indispensable Element

Silver mining in Anatolia is estimated to date back to the 3000s BC. This precious metal aided the development of early civilizations. By 1200 BC, the center of silver production shifted to the Laurium mines in Greece and continued to feed the region's growing empires, even providing currency for ancient Athens. By 100 BC, the center of silver mining had moved to the Iberian Peninsula (Spain) under Roman Empire control. However, no single event in silver history can be as impactful as the seizure of abundant silver deposits in the Americas by European conquerors following Christopher Columbus's arrival in the New World in 1492. Spain's conquest of the American continent led to an increase in silver mining. Between 1500 and 1800, Bolivia, Peru and Mexico accounted for more than 85% of global silver production and trade, expanding Spanish influence in the New World and elsewhere. Mining subsequently spread to other countries, particularly the United States, with the discovery of the Comstock Lode in Nevada. Silver production continued to grow, ranging between 40 and 80 million ounces annually in the 1870s. The period from 1876 to 1920 witnessed a boom in both technological innovations and the exploitation of new regions worldwide. In the final quarter of the 19th century, production quadrupled above the average of the first 75 years, reaching approximately 120 million ounces per year. New silver discoveries in Australia, Central America and Europe contributed to total global silver production. The twenty years between 1900 and 1920 resulted in a 50% increase in global production, bringing the total to approximately 190 million ounces per year. These increases were supported by new discoveries in Canada, the United States, Africa, Mexico, Chile, Japan and elsewhere. Throughout the 1900s, new mining techniques contributed significantly to increases in total silver production. Advances included steam-powered drilling, mine dewatering and improved transportation. Additionally, improvements in mining techniques increased the ability to separate silver from other ores and enabled the processing of larger quantities of material. These new methods were critical for the growing production volume, as most of the world's high-grade ores had been largely depleted by the end of the 19th century. Thousands of years after ancient cultures began mining in relatively small quantities, silver production reached approximately 855 million ounces by 2018. Mexico is the leading producer of silver, with Peru and China as other major producers.

Industrial Applications of Silver

Silver is used as an important component in many industries, from electrical switches to solar panels, from photographic film to catalysts used in chemical processes. Its unique properties make it nearly indispensable, and its applications span a wide variety of uses.

Silver and Solar Panels

Silver plays a vital role in the production of electricity-generating solar cells. Silver powder is converted into a paste and then applied to a silicon wafer. When sunlight strikes the silicon, electrons are released and silver, an excellent conductor, immediately carries the electricity for use or sends it to batteries for later consumption. Recent technological advances have made it possible to use silver, a relatively expensive element, in smaller proportions in the photovoltaic (PV) field. However, given many countries' commitment to generating electricity from renewable energy sources including solar, it is possible to predict that PV sector demand for silver will continue to increase. For example, Australia, Europe and India are expected to install increasing numbers of solar energy systems in the coming years. Silver in Electronics Many computers, mobile phones, automobiles and devices contain silver. Due to its high electrical conductivity and durability, it is an excellent material for plating electrical contacts – as in printed circuit boards. It can be said that if any device has an on/off button, it likely contains silver. China, the United States, Japan, Germany and India are the main demand centers in this category. Silver's excellent electrical conductivity makes it a natural choice for all types of electronic devices, from printed circuit boards to switches and TV screens. Silver membrane switches, requiring only light touch, can be used in buttons on televisions, phones, microwave ovens, children's toys and computer keyboards. These switches are extremely reliable and can successfully perform millions of on/off cycles. Silver is also used in traditional on/off switches, such as those used to control room lights. For printed circuit boards used in consumer products from cell phones to computers, silver-based inks and films can be applied to composite boards to create electrical paths. Painting any non-metal surface with silver ink allows electricity to be transmitted without requiring cables. Similarly, very thin antennas in Radio Frequency Identification Device (RFID) chips used in hundreds of millions of products can be made with sprayed silver.

Silver as a Catalyst

Catalysts aid in the occurrence of chemical processes. The most common catalyst is heat, but sometimes a catalyst can be a substance that facilitates the process without undergoing any transformation. Silver is a common catalyst in many production processes that produce products we use every day. Due to its unique chemical properties, silver plays a vital role in the production of two major industrial chemicals: ethylene oxide and formaldehyde. Silver is used because it remains essentially unchanged during the reaction and is thus nearly completely recovered after use. Ethylene glycol is produced from ethylene (ethene) via intermediate ethylene oxide. Ethylene oxide reacts with water to produce ethylene glycol. Silver catalysts can also be used to produce formaldehyde, a chemical produced from methanol. Solid plastic adhesives and lamination resins for construction plywood and laminate sheets are built from formaldehyde. Formaldehyde also helps produce paper and electronic equipment, textile products, heat and scratch-resistant surface coatings, tableware and buttons, coverings and handles for household goods.

Soldering and Brazing

When metal parts such as pipes, fittings, channels and electrical wires are joined, the process is called soldering or brazing depending on how much heat is applied to the joint. Joining materials at specific temperatures is called soldering, while joining at higher temperatures is called brazing. Adding silver to soldering or brazing helps produce smooth, leak-free, electrically conductive and corrosion-resistant joints. Silver solder alloys are used in virtually every field from air conditioning and refrigeration to electrical power distribution. They are particularly important in the automotive and aerospace industries. Silver brazing and solders combine high tensile strength, ductility and thermal conductivity. Silver-tin solder is used to solder copper pipes in homes, where it not only eliminates the use of harmful lead-based solders previously used, but also provides silver's natural antibacterial effect to the pipes. Major faucet manufacturers also use silver-based bonding materials to include these advantages. Refrigerator manufacturers use silver-based bonding materials to provide the flexibility needed for continuous temperature changes in cooling tubes. Without silver, none of these bonds would be as strong, leak-free or electrically conductive as the original materials.

Silver Use in Bearings

Motors operating continuously at high temperatures require a stronger bearing type than other machines. This is where silver comes in. When steel ball bearings are electroplated with silver, they become stronger than any other bearing type. For example, jet engines rely on silver-plated bearings because they can operate continuously at very high temperatures, and helicopter engines similarly benefit from silver's properties. Silver-plated steel ball bearings are not only strong, but silver also acts as a lubricant, reducing friction between the bearing and raceway. This improves engine performance and extends its life. Despite high internal temperatures, silver-plated bearings provide superior performance and a critical safety margin for engines. When silver is present as a thin film between hard slippery surfaces, it functions as a solid lubricant film due to its distinct ductility. For example, even in the event of an oil pump failure, silver-plated bearings can provide enough lubrication to allow the engine to shut down safely before serious damage occurs.

Silver Use in the Medical Sector

Even before people fully understood how silver worked as an antibacterial agent, this metal was used to prevent the growth of dangerous microbes. For example, on long ocean voyages, silver coins were thrown into water and wine casks to keep liquids fresh. In the past, doctors placed a few drops of silver nitrate in newborns' eyes to prevent infection. During World War I, on battlefields soldiers' wounds were wrapped in silver foil and silver sutures were used to close deep wounds. Today, silver coatings may be preferred on medical devices such as catheters to help combat infections. Silver is also used in bandages and ointments due to its property of keeping bacteria at bay. How silver works as a biocide has been revealed more clearly in studies conducted in recent years. Silver ions have the property of penetrating the cell walls of bacteria and destroying the chemical and structural bonds necessary for those bacteria to survive.

Silver and Automobiles

Every day, motor vehicles are becoming increasingly computerized, and silver plays a vital role in these operations. For example, in many modern automobiles, electrical connections are enabled by silver-plated contacts. Starting the engine, opening electric windows, adjusting electric seats and closing an electric trunk can be accomplished using silver membrane switches. Silver is also seen in high-performance spark plugs.

Silver in Water Treatment

Silver can prevent bacteria and algae from accumulating in filters. Working in concert with oxygen, silver serves as a powerful disinfectant, offering an alternative to or an enhancement of other disinfection systems. In hospitals, water treatment systems, swimming pools and spas, silver ions can be added to water treatment systems. Silver ions can even find their way into water treatment systems on spacecraft. Waterborne diseases are a major problem in developing countries. It has not yet been fully seen how much silver can help with clean drinking water, but ongoing research suggests that its use would be an exciting development for global water supply.

Photographic Film as a Nostalgia

Photographic film captures the image created by light reflected from the photographed surface. The sensitive elements in film are often silver halide crystals that can change their structure when excited by light (photons). Despite being used extensively in past years, films have now completely fallen out of use. Digital photography has replaced film photography among consumers and even professionals. For this reason, the use of silver-based imaging has been continuously declining for years. In spite of this, silver-based films can still be used for X-rays, particularly in developing countries due to their cost-effectiveness. Additionally, although rare, silver-based films may still be preferred for some commercial moving images due to their vibrant colors and detail.

Silver – An Indispensable Element

Of course, every element is unique in its own way, but silver's properties place it in a special position among all substances found in the periodic table of elements. For example, silver is malleable and ductile, making it a perfect choice for jewelry and silverware. Because it is one of the world's most reflective materials, silver possesses a unique luster and has played a very important role in mirror making. Silver oxide batteries are used especially in watches, calculators, toys and remote controls. Silver oxide batteries are the preferred power source for various miniature medical devices due to their reliability and performance. Along with those mentioned and not mentioned in this article, silver is used in countless fields. For this reason, it would not be incorrect to say that silver is an indispensable element. Prepared by: B.Serhat Cengiz References • NASA Technical Memorandum 86943, The Role of Silver in Self-Lubricating Coatings for Use at Extreme Temperatures, Harold E. Sliney, Lewis Research Center, Cleveland, Ohio. •Silver, Henrietta Toth. Enslow Publishing, LLC, Jul 15, 2018. Silver: Nature and Culture, Lindsay Shen. Reaktion Books, May 15, 2017. • https://www.hvacschool.org/2017/06/when-to-solder-and-when-to-braze-copper-lines-a-look-at-the-pros-and-cons-of-each/ • https://www.americanchemistry.com/ProductsTechnology/Ethylene-Oxide/What-Is-Ethylene-Oxide/ • https://phys.org/news/2019-04-solar-panel-demand-spike-worldwide.html • http://www.lbma.org.uk/assets/Alchemist/Alchemist_90/Alch90OConnell.pdf • https://www.boschautoparts.com/en/auto/spark-plugs/silver-spark-plugs • https://electrolurgy.com/wp-content/uploads/2015/06/Use-of-Silver-in-Connector-Applications-M-Myers.pdf • https://www.nature.com/news/silver-makes-antibiotics-thousands-of-times-more-effective-1.13232#/b1 • https://www.sciencemag.org/news/2015/05/silver-turns-bacteria-deadly-zombies# • https://www.chicagotribune.com/lifestyles/ct-xpm-2014-02-16-ct-nanosilver-met-20140216-story.html • https://spinoff.nasa.gov/Spinoff2004/er_1.html • https://www.varta-microbattery.com/en/products/silver-oxide/primary-silver-oxide • https://www.silverinstitute.org/ • Images: https://pixabay.com/