Let’s start with the properties of gold

Gold

Gold is a precious metal and one of the earliest metals discovered and developed by humans. It is an important raw material for making jewelry and coins, and an important reserve material for the country. It is known as the "King of Metals". It is not only regarded as a symbol of beauty and wealth, but also benefits human life with its unique value. With the development of science, technology and modern industry, gold is increasingly playing an important role in aerospace, medicine, electronics and other industrial sectors. The uses of gold are becoming more and more widespread, and the consumption is also increasing, which has aroused special concern and strong interest in gold from countries around the world.

Gold’s atomic number in the periodic table of chemical elements is 79, and its atomic weight is 197. Gold is heavy, but lighter than platinum. The density of gold is 19.32 g/cm?, that is, a gold ball with a diameter of only 46 mm weighs 1 kilogram. Pure gold is golden yellow, but in nature, pure gold is extremely rare. The color of gold changes with the content of impurities: silver and platinum can make gold lighter; copper can make gold darker. Colloidal gold displays different colors depending on its degree of dispersion and slightly sticky structure.

Gold has good ductility. One tael of pure gold can be hammered into gold leaves one ten thousandth of a millimeter thick, which can cover an area of ??nine square meters. Gold leaves are transparent and can glow green when sunlight passes through them. 50 grams of pure gold can stretch eight thousand meters, which is thinner than hair (∮1.6 strands, human hair 7 strands). The volatility of gold is small. Under normal circumstances, the amount of gold evaporated by melting is negligible. The loss of gold in evaporation in gas is six times that in air. The loss of gold in carbon monoxide is twice that in air. The volatilization speed of gold is similar to that in air. Impurity content has a lot to do with it.

Gold has good electrical and thermal conductivity. The electrical conductivity of gold ranks third among metals after silver and copper, and its thermal conductivity is 74% of silver. Gold is chemically very stable. Gold will not be directly oxidized by oxygen at low or high temperatures. At room temperature, gold does not work with individual inorganic acids (such as hydrochloric acid, nitric acid, sulfuric acid), but mixed acids such as aqua regia (three parts hydrochloric acid and one part nitric acid) and cyanide solutions can dissolve gold well. The melting point of gold is 1063°C. If gold is heated to close to its melting point, gold can be welded like iron, and fine gold particles can be sintered into blocks. However, gold powder must be fused together under low temperature, and pressure must be applied to fuse it together. Gold can be alloyed with other metals, such as gold-silver alloy, gold-copper alloy, and gold-silver-copper alloy. In addition, there are so-called gold amalgams.

Gold often exists in the state of natural gold. Natural gold containing silver and copper impurities is essentially different from alloys of these metals. Alloys are products of metal melting and solidification, so they have a homogeneous structure. Natural gold is precipitated from an aqueous solution. Natural gold is sometimes covered with a thin film of iron oxide. In this case, the color of gold may be brown, dark brown, or even yellow. This kind of gold generally has a coating layer. This coating layer is not just iron oxide, but sometimes it may be some fine-grained gangue attached to the surface of the gold particles. This coating not only affects the identification of gold, but also makes it more difficult to process mineral beneficiation (mercury amalgamation or cyanidation).

Gold is the king of hardware. It is a rare metal with excellent chemical, physical and electronic properties. It has a wide range of applications. It is used in electronics, communications, aerospace, chemical industry, medical and other sectors as well as in people's daily life. There is also a wide range of application space in various daily necessities related to life.

With the rapid development of the modern electronics industry, the requirements for reliability are getting higher and higher, and gold has high stability that cannot be replaced by other metals. At the same time, as electronic products become increasingly miniaturized, the amount of gold used per unit will be very small, posing no threat to product costs. Therefore, more and more electronic components can use gold as raw material.

Gold is also widely used in the aerospace field due to its high temperature resistance and corrosion resistance. As a large number of aerospace technologies are applied to civilians, the market prospects of gold in these aspects are very promising. For example, a kind of gold-plated glass is used to protect against ultraviolet rays in aerospace. It can now be used in buildings and can provide good protection against solar radiation and heat insulation.

Gold can also be used in daily necessities, such as gold-plated clocks, belt buckles, lighters, pens, etc. Switzerland, the kingdom of watches and clocks, is not a big country, but its jewelry industry uses about 40 tons of gold every year, 95% of which is used in the watchmaking industry. Only one watch factory in Japan consumes 1 ton of gold salt a year, which is equivalent to consuming 680 kilograms of gold. As the living standards of our people improve, the prospects for using gold for electroplating will also be very broad.

Gold has extremely high corrosion resistance, good electrical and thermal conductivity. The atomic nucleus of gold has a large effective cross-section for capturing neutrons; its reflection ability of infrared rays is close to 100%; it has various catalytic properties in gold alloys; gold also has good craftsmanship and is easily processed into ultra-thin gold foil, Micron gold wire and gold powder; gold is easily plated on the surface of other metals, pottery and glass, and gold is easily welded and forged under a certain pressure; gold can be made into superconductors and organic gold, etc. Precisely because gold has so many beneficial properties, it is widely used in modern high-tech industries, such as electronic technology, communication technology, aerospace technology, chemical technology, medical technology, etc.