Chapter 12 Section 4 The invention of saltpeter, sulfur and gunpowder

The basic ingredients of traditional Chinese gunpowder are saltpeter, sulfur and charcoal.Sulfur can also be replaced by realgar, and charcoal can also be replaced by oil and pitch.The key to the invention of gunpowder lies in the identification and performance of saltpeter (also known as flame salt) and the progress of its processing and purification process. The use of saltpeter in our country is very early. At the beginning, it was written as "disinfected stone", and it was used as medicine in the Warring States period.Its chemical composition is potassium nitrate.Saltpeter in nature is often formed by the decomposition of nitrogen-containing organic substances in the soil under the action of bacteria, oxidized into nitric acid, and then combined with potassium in the soil.So whenever the autumn season is high and crisp, it usually precipitates out in the shape of a shell or salt flower, covering the ground and the foot of the wall. This is the so-called ground frost.Especially in the corners near pigpens, stables, and toilets.The nitrater sweeps up this nitrate-containing clod, puts it in a bucket, and soaks it in water.After filtering, the filtrate is boiled or dried to obtain saltpeter crystals.Also, it is occasionally found on certain rock faces, caves, or salt marshes.According to its "fossil" nature, "Pu Xiao", which was recorded in the book of the Eastern Han Dynasty, "can transform seventy-two kinds of stones", is probably saltpeter.

After the rise of alchemy in China, alchemists attached great importance to saltpeter, and constantly explored its properties, saying that it was "born from the air of sea brine, and it is the most divine thing in the world... It can turn seventy-two petrochemicals into water, and soften hardware. , to refine the eight stones, even the great alchemy would not give up this."In the early Chinese Danjing "Thirty-six Water Methods" published in the Eastern Han Dynasty, saltpeter is the protagonist. However, there is a substance called "glauber's salt" quite widely in nature, and its chemical composition is NaSO·10HO, which will be precipitated in large quantities around the salt lake; It is often isolated from saline-alkali ground, and its appearance is quite similar to saltpeter.In traditional medicine of our country, the medical functions of the two are almost identical.Therefore, the ancients, especially from the pre-Qin period to the Southern and Northern Dynasties, often confused them. Of course, the records in ancient books are quite confusing. What is real saltpeter?For a long time, there were different opinions.Therefore, in order to collect saltpeter extensively, make full use of it, and accurately grasp its chemical characteristics, we must find some ways to distinguish them.In the Southern and Northern Dynasties, Tao Hongjing proposed a method of identifying saltpeter, which was quite scientific. He said: "burn it with fire, and the purple smoke will rise, and the cloud is real saltpeter. There are saltpeter in the mountains north of Dangchang (in today's Gansu). It’s everywhere in the soil.” That is to say, if you put real saltpeter on the flame and burn it, it will make the flame purple, which is different from Glauber’s salt.We know that sodium sulfate will tint the flame yellow.This is the modern flame test method, which was used by ancient Chinese alchemists as early as 1500 years ago.However, when this method is actually used, it often encounters difficulties.Because natural saltpeter always contains some Glauber's salt and salt, and the yellow flame produced by sodium is far brighter than the purple flame of potassium, so the existence of a small amount of sodium impurity, this method of flame color identification will be invalid strength.In the Tang Dynasty, alchemists invented the highly efficient "sulfur nitrate method" to make lead elixir.The process is to use molten lead to react with sulfur to produce lead sulfide, and then add saltpeter to fry together, and soon red lead red will be produced, but Glauber's salt has no such function, so it is a kind of A scientific method for the identification of saltpeter.But in the Tang Dynasty, alchemists more generally knew that saltpeter could be identified by its combustion-supporting properties: throw a small piece of saltpeter to be tested on the red hot coal, and it would burn violently; It turns into "water" first, and after the water evaporates, it turns into a white powder like dry alum, which is quite different from saltpeter.Therefore, the alchemists in the Tang Dynasty made great strides in understanding the properties of saltpeter and using it in multiple ways. It is not accidental that they invented gunpowder during this period.

The research and utilization of sulfur came later than that of saltpeter, which may be due to the lack of natural sulfur in the Central Plains.It is recorded that it "can transform gold, silver, copper, and iron", which shows that the Han Dynasty has learned that sulfur can corrode various metals.In the early Han Dynasty, sulfur was obtained mainly from the volcanic areas in the Western Regions.According to records, there was a volcano in the Yueban area (today's Kuqa area, Xinjiang) at that time, "the rocks beside the mountain were scorched and melted, and the flowing ground was solidified for tens of miles, that is, stone and sulfur."However, in the Han Dynasty, the Central Plains area also began to extract sulfur from black coal-bearing pyrite (called Nieshi at that time, because it was the raw material for firing green vitriol, so it was also called alumite).It is a process of making green vitriol: in a kiln made of adobe, the ore and coal are piled up, ignited and roasted, and the following reactions occur:

FeS+2O＝FeSO+S↑ Sulfur condenses from the top of the kiln (Figure 3-10).Therefore, in the Eastern Han Dynasty, sulfur was also known as "alumite liquid".Because sulfur can burn violently, alchemists regard it as the essence of flint; it is also called "general" and "gold thief", probably because it can corrode various metals.It has played an important role since the rise of alchemy in China. Chinese alchemy mainly uses the method of fire refining from beginning to end, and saltpeter and sulfur are the most commonly used agents, and one is "Yin Jun" (saltpeter) and the other is "Yanghou" (sulphur), so they are used in Danding. When encountering the middle phase, there are many opportunities to be heated together. If the alchemist has a whimsy, and then mixes some herbs, oils, honey and other things to form an original gunpowder formula, it will inevitably happen. "The catastrophic accident.In the Tang Dynasty, an alchemist named Zheng Siyuan wrote a book on alchemy called "The Essentials of the True Yuan and Miao Dao", which once said: "Some people burn it with sulfur, realgar, saltpeter and honey. Those who burn the house." And warned: "Saltpeter cannot be burned with three yellows (sulphur, realgar and orpiment), [otherwise] you will see disaster immediately." It refers to this situation.Ge Hong's "Baopuzi Nei Pian Immortal Medicine" contains a "method of taking realgar", which is to stir realgar and saltpetre with pig large intestine, put it in a crucible and cover it with fire.In this case, if the proportion of saltpeter is large, an explosion will occur.Of course, while these "disasters" continue to occur, alchemists are also summing up experience and lessons. On the one hand, they try to avoid such "disasters" from happening, so they sum up many measures and means to "denature" saltpeter and sulfur in advance. That is, various "sulfur sulfur method" and "sulfur saltpeter method", transforming them into other substances to subdue their "violent character"; Especially those alchemists who are also "military divisions" are more interested in this, they believe that this will greatly enhance the power of the fire attack.This led them to the invention of gunpowder and the development of firearms.

In the alchemy works of the Tang Dynasty, there have been many methods of "Fu Sulphur" and "Fu Ni Shi".But when warlocks invented gunpowder, it has not yet been accurately verified. There are different opinions and great differences, and most people tend to be in the middle Tang Dynasty.They have the following basis: some of the Fuhuo formulas in the alchemy works at that time were actually primitive gunpowder formulas, and they were known to explode, so careful precautions were taken. This is one of them; In the separatist regime, Li Xilie occupied Bianliang (now Kaifeng) and proclaimed himself emperor. Liu Qia went to crusade and invaded Songzhou (now Shangqiu). It is possible that rockets filled with gunpowder were used, which is the second; according to Lu Zhen's "Nine Kingdoms" records: In the early years of Tang Aizong Tianyou (904-905 A.D.), Zheng Fan attacked the rebels in Yuzhang (now Nanchang). Long Shamen was burned with "engine flying fire". That kind of "flying fire" is probably the burning material filled with gunpowder, which is the third.But even in the early Song Dynasty, gunpowder was still in its infancy, and only a few people mastered it. Rockets, fireballs, and fire thorns were all amazing new weapons.However, it can also be seen that the development was being stepped up at that time.In the first year of Song Renzong Kangding (AD 1040), Zeng Gongliang and Ding Du wrote a comprehensive military book "Wu Jing Zong Yao" (written in AD 1044), which officially recorded three gunpowder prescriptions (Fig. 3-11), one is poison smoke ball gunpowder, which is a gunpowder that has a relatively low combustion temperature and emits thick smoke and poisonous gas (which is mixed with highly toxic herbal medicines such as Aconitum, Croton, Wolf's Poison and arsenic). One is artillery gunpowder, which burns violently and is used to burn the enemy’s luggage, food and grass; the other is caltrop fireball powder, which has a strong explosive force. When the gunpowder explodes, it will spread a large number of caltrops, which can stop the enemy’s cavalry. go ahead.

During the reign of Song Shenzong Xining (1068-1077 A.D.), the military system was reformed, and a military weapon supervisor was set up to take charge of the military production of the prefectures in the capital. The scale was large and the division of labor was very detailed. There are workshops, including workshops specializing in the development of gunpowder.Since then, gunpowder has made rapid progress. By the end of the Northern Song Dynasty, there were already very explosive weapons such as "thunderbolt gun" and "shocking thunder", which showed that at that time, there was already a lot of experience in purifying flame nitrate.According to the self-report of Li Gang, an anti-gold general in the Northern Song Dynasty, in the first year of Jingkang (1126 A.D.), he used thunderbolt cannons to repel the siege of Bianliang by Jin soldiers.At that time, the shells were already made of iron, and they were extremely powerful.According to the "Golden History" description, this kind of artillery "exploded gunpowder, the sound was like thunder, and the heat reached more than half an acre. Both human and cowhide were smashed without trace, and armor and iron were penetrated" (Figure 3-12).

China's gunpowder has been greatly improved in the Song, Jin, and Yuan dynasties due to military needs. In the 13th and 14th centuries, with the trade between China and West Asia, especially the two large-scale invasions westward by the Mongols, gunpowder technology and firearms were first introduced to Arabia, and then to European countries. After the invention of gunpowder, designers and craftsmen have to continuously improve it and try to increase its power.In addition to the adjustment of gunpowder formula, the more important thing is to improve the purity of saltpeter and sulfur.Therefore, during the Yuan and Ming Dynasties, the gunpowder workshop really worked hard on the purification process of nitrate and sulfur.Regarding the purification of saltpeter, there was still no great improvement until the Song Dynasty, and it was simply decocted, evaporated, concentrated, and recrystallized.In the Yuan Dynasty, Zhu Zhenheng, a famous doctor, mentioned in his "Danxi Heart Method" that he used radish to purify Glauber's salt, that is, boiled radish slices with Glauber's salt solution, then filtered and recrystallized.In this process, the magnesium sulfate and some salt in Glauber's salt are removed by the adsorption of radish, so that Glauber's salt changes from "salty and bitter" to "sweet".In the Ming Dynasty, this method was extended to the purification of saltpeter, because MgSO·7HO has a strong deliquescent property, and gunpowder made from saltpeter containing this impurity is bound to be easily dampened and invalidated.This method of raising nitrate is recorded in the "Fire Dragon Classic", a monograph on gunpowder and fire attack techniques in the early Ming Dynasty, and in the "Shen Qi Pu" written by Zhao Shizhen in the 26th year of Wanli (AD 1598).It also mentioned that after dissolving the saltpeter, some alum and gum should be added first, and then boiled with the radish.In this way, after filtration, concentration and crystallization, not only magnesium salts, but also impurities such as fine sand, gypsum and iron mixed in the original saltpeter will be removed together.If the saltpeter contains a lot of salt, then in this process, due to the different effects of temperature on the solubility of NaCl and KNO, the salt will remain in the solution and be separated.In the reign of Tianqi (1621-1628 A.D.), the "Wu Bei Zhi" written by Mao Yuanyi improved the method of raising nitrate.He instructed to use gray frost (ie KCO) to precipitate and remove magnesium salts, calcium salts and iron salts in saltpeter.Obviously, its effect is better than the carrot method, but very close to the method in the modern chemical laboratory.

As for sulfur, whether it is collected from volcanic areas or smelted from pyrite, the purity is relatively high, mainly due to some mud and sand.Therefore, its purification method did not appear until the Ming Dynasty when gunpowder and firearms developed greatly, and the most important one was the frying method. There are records in "Wu Bei Zhi" and Jiao Xu's "Fire Attack" (AD 1643), but the "Sulfur Diary" written by Yu Yonghe in Qing Dynasty is the most detailed.This is a memoir of his purchase of sulfur in chicken coops (now Keelung) and Danshui in Taiwan after the gunpowder depot in Dongrong City (now Fuzhou) was burned down in a fire in the thirty-fifth year of Emperor Kangxi of the Qing Dynasty (1696 A.D.).This method of extracting sulfur is to put rapeseed oil (sesame oil in "Wu Bei Zhi") into the large iron kettle first, and then put the powdered sulfur soil into the oil, but do not heat, stir vigorously, and the sulfur powder is light. And it is lipophilic, so it floats in the oil layer to form a suspension; the sand grains are heavy, and they sink to the bottom of the kettle.After standing still for a while, scoop the oil mixed with sulfur into another kettle, and when it is heated to near boiling, the sulfur melts, then condenses and sinks to the bottom of the kettle.After cooling, the sulfur will condense into blocks, take it out, break it up and use it.Oil can be reused over and over again.

In the late Northern Song Dynasty, gunpowder was applied to entertainment again.Those early firecrackers, shooting stars, and pyrotechnics seem to have been created based on experience with military applications.In the Southern Song Dynasty, the elder Meng Yuan of Bianliang wrote a book "Tokyo Menghualu", which traced the scenes of Fengfu, a figure in the capital, and the bustling streets in the reign of Emperor Huizong from Chongning to Xuanhe (AD 1102-1125), and mentioned the palace. Firecrackers and fireworks... It is said that during the performance of Baixi, there are firecrackers, "with a thunderbolt, ... the fireworks explode, masks are scattered, and ghost-like people appear on the stage breathing smoke and firework with wolf teeth."That kind of firecrackers, according to the "Kaiji Zhi" written by Shi Shi, "uses sulfur as the explosive, and the sound is especially loud", and it is definitely not the kind of "firecrackers" that burned bamboo in the past.By the early Southern Song Dynasty, there probably had been the kind of large-scale pyrotechnic shows that were released on wooden frames, with heavy curtains falling, and pavilions, pavilions, birds and animals appearing from time to time.At that time, in the "Mengliang Lu" written by Wu Zimu, there was already a saying that "in December, there are firecrackers sold, fireworks and the like".Zhao Mengfu, a versatile literati at the end of the Song Dynasty and the beginning of the Yuan Dynasty, once wrote a poem describing the fireworks at that time and praising the pyrotechnic craftsmen. The poem wrote:

The ingenuity in the world is amazing, refining medicine and burning lamps are the same day and night. The catkins fly and the ground is white, and the peach blossoms are all red. One after another, they are as brilliant as falling stars, and they are as noisy as fire. At night, turn the flowers on the brocade, and don't worry about falling to the east wind.