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"Tiangong Kaiwu" is a treasure of ancient Chinese science and technology, which contains all kinds of skills and products in detail. If you want to study the chemical properties of the sand and moraine of rivers, let me say it in ancient Chinese.
The chemical properties of the sand and moraine of rivers vary depending on the region and source. Generally speaking, sand and moraine are mostly a mixture of silicon, calcium and other minerals. Silica is often the main one, and its texture is hard and its chemical properties are relatively stable. Under normal temperature and pressure, it is not easy to react with common acids and bases. Even when encountering strong acids such as sulfuric acid and hydrochloric acid, it is difficult to dissolve or undergo significant chemical changes.
As for the calcareous component, it is mostly in the form of calcium carbonate. This is a more active component, and it is prone to chemical reactions when exposed to acid. In case of dilute hydrochloric acid, calcium carbonate will react with it to form calcium chloride, water and carbon dioxide gas. The reaction formula is: CaCO < 2 HCl = CaCl < 2 HCl + H < 0 + CO < 3 ↑. This reaction is common in many geological changes and industrial processes.
In addition, the sand and moraine of rivers or compounds containing trace amounts of iron, aluminum, magnesium and other metal elements. Iron compounds, or in the form of oxides, can be reduced to elemental iron when exposed to strong reducing agents such as carbon monoxide under high temperature conditions. The properties of aluminum compounds are also different, and some can react with alkalis to form metaaluminate and water.
The sand and moraine of rivers, although simple in appearance, have complex and diverse chemical properties. The stability of silicon, the activity of calcium, and the characteristics of other trace element compounds are intertwined to form their unique chemical properties. This is the work of natural creation, and it is also an important object for our generation to explore the mysteries of nature.

Mercury is a common gold, and its synthesis method has been widely observed in ancient times. The synthesis method of mercury is not yet known in "Tiangong Items", but some common methods can be found in the.
First, it can be reversed by. Mercury can be biochemically combined and reversed under specific conditions. For example, mercury-containing substances such as Dansha (mercury sulfide) and mercury-containing substances such as square (sulfide) can be mixed in a certain proportion, placed in the crucible, and added at a suitable temperature. In this way, mercury sulfide is decomposed into mercury vapor, and the mercury vapor of sulfide can be reacted under certain conditions, forming amalgam or other compounds. It should be noted that the heat control is not complete, and the heat is not enough to make the mercury low, so that the mercury can be effectively synthesized.
Second, the melting method is also commonly used. First, the mercury is placed in the melt, and it is added to the appropriate temperature to keep the mercury in the liquid. And then, the slow addition of mercury, not mixing. Due to the low melting temperature of mercury, the liquid can be maintained at a certain temperature, and the addition of mercury can be dissolved in the mercury one by one to form mercury (amalgam). In the melting process, it is necessary to pay close attention to the melting degree to avoid the uneven composition of the alloy due to the large fluctuation of the temperature, which will affect the synthesis effect.
Third, use the solution to synthesize. The total amount of mercury is dissolved in a suitable solution, such as a mercury nitrate solution and a nitric acid solution. And then, without mixing, slowly mix the solution. In this case, the mercury in the solution may react and form new compounds. Then through a series of operations such as washing, washing, and drying, the required mercury compound can be obtained. This method requires high control of solution strength, reaction strength and reaction strength to obtain the ideal synthetic compound.

"Tiangong Kaiwu" has a saying: "Alum is found in Jin, Shaanxi, Shu, and Western Guangdong counties, and also comes out of the seashore. Stones produced in Shanxi and Zhejiang are all blue and white."
Alum substances are produced in Jin (now Shanxi), Shaanxi (now Shaanxi), Shu (now Sichuan), West Guangdong (now part of Guangxi), etc. Occasionally found in seashore. The stones required for production are produced in Shanxi and Zhejiang, and their color is white in green.
In many fields involved in "Tiangong Kaiwu", alum is widely used in metallurgy, dyeing, papermaking and other industries. In metallurgy, it can help metal separation and purification, remove impurities and maintain purity, so that the metal quality is better and the process is fine; in dyeing, it is a key mordant, and the fabric is treated with it, the dye adheres well, the color is firm and bright, and the dyeing workshop often relies on it; in papermaking, it can make the paper smooth and has anti-splashing properties. When scholars splash ink, the ink is not out of shape, which is an important thing for the quality improvement of paper products.
It can be seen that the alum produced in Jin, Shaanxi, Shu, Western Guangdong and coastal areas at that time played an indispensable role in many important fields and greatly promoted the development of industry and handicrafts at that time.

"There are many kinds of alum, and their properties are different." River alum and other alum species have their own unique physical properties.
The color of river alum is often light or nearly colorless, and it is clear like autumn water, giving people a sense of purity. Its texture is relatively delicate, and when touched, it feels slightly smooth, but it is not as greasy as greasy hands, but a refreshing smoothness.
As for its shape, it is mostly crystalline. Although the crystal is not huge, it is exquisite and delicate, like a miniature treasure carved by nature. Under the reflection of light, the surface of the crystal reflects light, flickering and charming.
The density of the river alum is slightly lighter than that of common stones. When held in the hand, it can be felt that its weight is moderate, there is no heavy pressure, and it is not light and nothing. Its hardness is not high, and it will leave marks when scratched with a sharp object. This characteristic makes it easy to process and shape, and craftsmen can carve it into various shapes as needed.
River alum is quite sensitive to temperature changes. When heated, it will gradually soften and change its shape quietly. If the heat is just right, it can melt into a flowing state, like smart water. This characteristic makes it widely used in many crafts. After cooling, it solidifies again into a solid state, and it can retain a certain shape, which can add another kind of beauty to the utensils.
River alum also has a unique performance in water. When placed in water, it will slowly dissolve, giving the water a slightly special taste. Although it is not pungent, it is different from ordinary water. Under certain conditions, its solution can undergo many wonderful chemical changes, providing assistance for traditional crafts such as dyeing and tanning.
The physical properties of river alum make it occupy a place in many industries in ancient times, used by skilled craftsmen to create many exquisite objects and practical arts.

The price of Guanfujiang paper is related to the supply and demand of the city, and it also depends on the quality of the goods. In the past, Jiang paper was first flourishing, and there were many people seeking it in the city. However, the amount of production was small, and the price was high. If the pearl was in the city, everyone would compete to buy it, and the price was high but not easy to get.
Catch the time and change, the industry is refined, the amount of production is gradually increasing, and the demand of the city may also change. If the amount of production is far more than the demand, the price will drop, like a flood, which is unstoppable. On the contrary, if the demand is very high, and the production is difficult to continue, the price will rise. It is still the grain of dry years, which is very precious.
And the quality of Jiang paper is also the key to the price If the quality is high, the texture is delicate, the color is radiant, and the writing is smooth, then the price is high, which is reasonable. The supply of good paper is sufficient, and those who are good at paper are still willing to pay a lot of money for it. If the quality is poor, rough and difficult to use, even if the supply is scarce, no one will care about it, and the price will be low.
There are various external forces that affect the price. The regulations of the government and the change of the tax can make the price fluctuate. If the tax is increased, the cost of the merchant will increase, and the price will also rise accordingly. If the government supports and encourages production, the production will be easy, and the price may drop.
As for the paper of the neighboring city, it is also a factor that affects the price of paper. If the paper in the neighboring city is of high quality and low price, the market may turn to it, and the price of Jiang paper will be affected. On the contrary, if the paper in the neighboring city has a high secondary price, Jiang paper can stabilize its price, and even take advantage of the situation.
From this perspective, the market price of Jiang paper can not be determined at one end. Supply and demand, quality and quality, and external forces are all intertwined, and the changes are endless. Businesspeople and seekers should judge the situation in order to be able to plan and gain in the changing situation of the city.