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Mercury is widely used. "Tiangong Kaiwu" has a cloud, mercury is used in all kinds of affairs, and each shows its ability.
First, in the art of alchemy, mercury is the key thing. Ancient alchemists believed in alchemy for longevity, and mercury was often the material for alchemy. With its characteristics, it can be combined with other things to obtain magical pills. There are many records of alchemy in "Baopuzi · Nei Chapters". Mercury often undergoes wonderful changes in it. Although its methods are absurd, people at that time believed it without a doubt, which shows the importance of mercury in the field of alchemy.
Second, it is used in medicine. Mercury and mercury compounds have been used in medicine to treat diseases. In the past, healers used it to treat scabies, sores and other diseases with its sterilization and disinfection effects. Such as light powder, that is, the preparation of mercury, can be used externally to attack poison and kill insects. However, mercury is very toxic, and if used inadvertently, it will harm patients, so it has been used with caution today.
Third, in the metallurgical industry. Mercury can form amalgams with metals such as gold and silver, which makes it used for extraction of gold and silver. Gold miners often use amalgamation to extract gold. Mixing gold and silver-containing ores with mercury, mercury can absorb gold and silver, and then evaporate the mercury by heating and other methods to obtain gold and silver, which is quite important in the development of ancient mining.
Fourth, in the production of handicrafts. Mercury can be used in the gilding process. Mercury and gold are used to make gold amalgam, which is applied to the surface of utensils, heated to volatilize the mercury, and gold is attached to the utensils to form the beauty of gilt. For example, many ancient bronzes and gold and silver utensils are decorated by this process, which is even more gorgeous.
Although mercury has various uses, its toxicity should not be underestimated. The ancients may not have known its poison and harm, but now they need to use it carefully. It is the right way to take advantage of it and avoid it.

Mercury is unique in its nature and is one of the hardware. Its color is silver-white, at room temperature, in the shape of a liquid, smooth and flowing, like a silver bead, with a dazzling luster.
The texture of mercury is soft and can be deformed at will, without a fixed state. Its density is quite large, heavier than ordinary things, and it feels heavy when held in hand. And mercury has good thermal and electrical conductivity, and it is often used in many appliances to conduct.
In addition, the volatility of mercury is also its remarkable characteristic. In a room temperature environment, mercury quietly evaporates and escapes in the air. Although it is invisible and colorless, it should not be underestimated. If inadvertently inhaled, it may cause human poisoning and damage the organs, especially the nervous system.
The chemical properties of mercury are relatively active and can react with many substances. In case of sulfur, the two quickly combine to form mercury sulfide, which is often used by the ancients to make pills and relieve mercury poisoning.
According to the "Tiangong Kaiwu", mercury is obtained from the refining of pill sand. When the ancients refined alchemy, mercury was often used as a key material. Because of its miraculous changes, it was combined with other things in the cauldron furnace, or into an elixir, in order to achieve longevity. However, they did not know the toxicity of mercury, and it would hurt the body if taken. And mercury is also used in many processes, such as gold plating and silver plating, which uses the properties of mercury to make gold and silver adhere to the surface of utensils, enhancing their beauty and durability. However, when operating, careful protection is required to avoid mercury poisoning.

Sodium and mercury are alloys formed by mixing sodium and mercury. Its chemical properties are unique and interesting.
Sodium is extremely active, and it ignites violently when exposed to water. The sound of bursting and splashing water is very strong. Mercury is liquid at room temperature, silver-white and bright, flowing unruly, and relatively stable in nature. The two are combined into sodium and mercury, and their properties change.
Sodium and mercury react slightly slower in air than pure sodium. The presence of mercury covers the surface of sodium to form an isolation film, which is like a barrier, slowing the reaction between sodium and air. However, this barrier is not indestructible, and sodium is still gradually oxidized after being placed in the air for a long time.
When it comes into contact with water, sodium and mercury also react. The activity of sodium still exists, and when it comes into contact with water, hydrogen is still generated. But its reaction intensity is inferior to that of pure sodium. The dilution of capping mercury makes the contact area between sodium and water and the reaction rate change. The hydrogen generated by the reaction slowly escapes, like a trickle in a spring, which is not as explosive as pure sodium in contact with water.
In chemical reactions, sodium and mercury are often used as reducing agents. It has the reducing properties of sodium and plays a role in many reactions. For example, in the field of organic synthesis, sodium and mercury can change the structure of some compounds and form new substances. This is because sodium atoms are prone to lose electrons and supply electricity to others.
The chemical properties of sodium and mercury are not only the activity of sodium, but also changed by the mixing of mercury. Its slow change in air, different reactions in water, and reduction properties in chemical reactions are all the wonders of chemical research and the foundation of various applications.

The method of smelting armor iron, the ancient good workers have their own techniques. In "Tiangong Kaiwu", there are roughly two methods.
One is the "stir-fried steel method". Melt the pig iron in the furnace, and wait for the molten iron to flow, pouring it into the square pond. One person stirred quickly with a willow stick, and everyone blasted to support the combustion. When the stick was stirred, the molten iron was in full contact with the air, and the carbon was gradually removed, turning the pig iron into wrought iron. This process requires seizing the opportunity. If it is stirred for too long, the iron will be too pure and brittle; if it is not stirred enough, the carbon will not be removed, and the iron will still be hard and difficult to use. When the iron is moderate, it can be taken out and forged.
The second is the "steel pouring method". Select high-quality wrought iron material, cut it into thin slices, place it in a crucible, and then place pig iron on it. Heat with fierce fire, the pig iron melts first, and the liquid iron seeps into the wrought iron. After many folds and forging, the iron and carbon are evenly integrated, and the rigidity and softness are combined. The iron made of steel is of excellent texture, and can be used to make sharp weapons such as swords.
For these two, the frying method is relatively simple to operate, and can be used for large-scale production of wrought iron for agricultural implements, daily utensils, etc.; the irrigation method pays attention to the improvement of iron quality, and the steel produced is suitable for making weapons and other materials that require extremely high hardness and toughness. The ancient method of smelting iron contains the wisdom of man-made things, which laid the foundation for the development of steel smelting technology in later generations.

Mercury is a highly toxic thing. When storing and transporting, many matters need to be cautious.
When storing, the first seal is heavy. Mercury is volatile, and its vapor is highly toxic. If it is leaked into the room, it will be dangerous for people to inhale it. Therefore, it must be contained in a tightly sealed device to prevent it from escaping. As "Tiangong Kaiwu" says, sealing is essential for all things, and so is the storage of mercury.
And hide in a low temperature and cool place. Mercury is active, and high temperature can easily cause its volatilization to intensify. It is best to choose a secluded and shady place, away from direct sunlight and high temperature.
As for the choice of storage, it is advisable to use strong and corrosion-resistant materials. Mercury is corrosive, and ordinary materials are easily eroded, causing mercury to leak out. Special devices must be used to ensure its safety.
When transporting, safety comes first. It is necessary to keep the mercury in the device without shaking or dumping. Drive slowly on the way to avoid bumps and vibrations.
The escort must have professional knowledge. Familiar with the nature of mercury, understand the way to deal with it. If there is a leak, you can quickly take good measures to prevent the spread of disasters.
Furthermore, the transportation process, strictly abide by the rules. Government laws, regarding the transportation of highly toxic substances, have regulations, and cannot exceed the rules. Only by following their regulations can you ensure a safe journey and not cause trouble to the people.
When storing and transporting mercury, sealing, temperature control, device selection, safety, personnel supervision, and compliance are all indispensable. All should be kept in mind and implemented with caution to ensure safety and avoid causing harm to others.