New uses of common metals

Silver, palladium, gold, platinum and rhodium are five precious metals, which are widely used in industry and become the darling of spot and futures markets.

In addition to silverware, the main uses of silver are also widely used in DVD players, refrigerators and other household appliances, and even silver nanotechnology in recent years. In addition, silver is also used as a medium for bleaching paper. Rhodium can be used as resistor, thermocouple, printed circuit, etc. Electronic and electrical industry.

Palladium was originally used in jewelry industry as an antioxidant surface processor. At the same time, this metal has catalytic effect, so it is often used as a catalytic converter, such as the catalytic converter of automobile exhaust pipe, which can achieve the effect of transforming and purifying organic substances and harmful substances in exhaust gas.

Gold has high conductivity and is used as a conductor in some high-energy applications. Wires like gold were used in the electronic experiments of the Manhattan Project. In addition, gold is also used in electronic connectors, switch contacts, electromagnetic radiation reflectors and photographic toners.

Platinum is used in aviation industry, and it is also needed to make glass fiber and man-made fiber. Advanced optical glass and laser crystal used in glasses, camera lenses and color TV picture tubes are all made of platinum. In addition, the waste gas purifier is also made of platinum, and magnets made of platinum and cobalt are the power sources of high-precision watches and miniature instruments.

Rhodium is a silvery-white transition metal, which exists in platinum ores and is also used as a catalyst in some platinum alloys, as an anti-wear coating and catalyst for high-quality scientific instruments. Rhodium-platinum alloy is used to make thermocouples, and can also be used as electroplating layer, which is often plated on searchlights and mirrors to enhance the luster and wear resistance of their surfaces. Excellent corrosion resistance to common acids and chemical reagents, so it is used in headlights, telephone repeaters, pen tips, platinum jewelry and so on.

In our life, iron can be regarded as the most useful, cheapest, richest and heaviest metal. In industrial and agricultural production, iron is the most important infrastructure material, and ferroalloys are widely used. National defense and war are even more a contest of steel, and the annual output of steel represents the modernization level of a country.

Iron is an indispensable trace element in human body. Among more than ten kinds of trace elements necessary for human body, the importance and quantity of iron rank first. A normal adult's iron content is above 3g, which is equivalent to the quality of a small nail. Hemoglobin in human blood is a complex of iron, which has the functions of oxygen fixation and oxygen transport. Iron deficiency in human body can cause anemia. As long as there is no partial eclipse and no bleeding, adults generally do not lack iron.

The so-called gas poisoning (carbon monoxide poisoning) is also due to the fact that the core of iron atoms in heme is tightly surrounded by carbon monoxide gas molecules, which loses the ability to absorb oxygen molecules and makes people suffocate and die.

Iron is also an indispensable catalyst for plants to produce chlorophyll. If a pot of flowers is short of iron, the flowers will lose their bright colors and refreshing fragrance, and the leaves will turn yellow and wither. Generally speaking, soil also contains many iron compounds. Iron is an important component in soil, and its proportion in soil ranges from less than 1% to more than 20%, with an average of 3.2%. Iron mainly exists in the form of iron oxides, including bivalent iron and trivalent iron, and most iron oxides exist in the form of microcrystals in different degrees in soil particles.