Chapter 196 Alchemy to produce smokeless propellant
Absorbent cotton has better hygienic effect than ordinary cotton for bandaging. The principle is obviously because some of the oil and protein components in ordinary cotton are not required for bandaging materials.
Oils and proteins are easily decomposed and utilized by bacteria and become "medium and nutrient solution" for cultivating bacteria and viruses. Therefore, medical cotton should be degreased and deproteinized as much as possible to leave purer cellulose.
However, the cotton requirements for making nitrocellulose are obviously different from those for medical cotton.
Some of the components removed from the medical cotton are actually needed when making nitrocellulose. If the components are removed too cleanly, the reaction will fail.
Therefore, when seeing Fang Yizhi's invention of medical absorbent cotton, Shen Shuren was grateful for this invention, but also had more hidden worries, thinking that the research and development of nitrocellulose had temporarily fallen into the wrong direction.
Fortunately, Fang Yizhi knew him very well. Just by looking at the change in his expression, he knew what he was depressed about. Originally, Fang Yizhi wanted to show off, but now he told the truth directly:
"My dear brother, you are really knowledgeable and knowledgeable. Do you also know that medical cotton and nitrocellulose cotton have different requirements for raw materials?"
When Chen Shuren heard this, he couldn't help but feel happy and had some expectations: "Why do you say 'ye'? That means you already know it? Mr. Song also knows it? Could it be that you have made both kinds of cotton?"
Fang Yizhi then showed a proud expression: "That's natural, and it's not difficult. When processing absorbent cotton, maybe too much lime alkali surface was used, and what came out was indeed missing a lot of useful ingredients.
But since we know the reason behind it, and also know that Red-haired Yi scholars have used this idea to create collodion, we can just try and make changes over and over again, and how can we still not figure this out in a few months?"
Chen Shuren was finally a little awe-struck: This person is incredibly smart. After being prompted by himself, is this enlightenment? He can actually understand the basic principles of acid-base balance and have a glimpse of the chemical common sense of acid-base balance.
Even if there is no breakthrough in the research and development of new gunpowder this time, just summarizing and recording this experience will definitely be of great help to the development of chemistry in this era.
He still asked with some fear: "So... you finally tried it out, which kind of pre-treated cotton is suitable for acidification? Then how did you do the experiment? Did you come up with the kind made with saltpeter?"
strong acid?"
Fang Yizhi didn't say anything, he just looked at Song Yingxing next to him and smiled, and first showed Shen Shuren a little bit of the mysterious finished product.
It was some grayish-yellow powder, slightly darker in color, but definitely not burnt black, which was different from Chen Shuren's imagination.
It may also be that Shen Shuren did not have a solid knowledge of chemistry in his previous life, or that he had seen the primer charges removed from the bullets of modern firearms in his previous life and knew that they were all black, so he mistakenly thought that nitrocellulose was also black.
In fact, nitrocellulose is grayish-yellow, which is not exactly the same color as the primer of modern bullets. Modern primers are also mixed with some other ingredients.
On the other hand, in the early production and manufacturing of nitrocellulose, if black color appeared, it was generally because the reaction was too violent, the heat generation and heat dissipation were not well controlled, the temperature increased, carbonization occurred, and impurities were incorporated.
The nitrocellulose displayed by Fang Yizhi at this moment is obviously not pure. With the technological level of the late Ming Dynasty, it is impossible to make it too pure.
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Shen Shuren took it in his hand and carefully observed it. He couldn't tell whether it was genuine or not, so he had to have someone take some of it and put it into a bullet for test firing.
Fang Yizhi was also prepared. He immediately asked someone to bring a revolver produced by the Daye Military Factory and a breech-loaded short-barreled double-barreled spray gun. He then demonstrated on the spot and asked a close craftsman to remove the paper bullet casing.
The charge inside was changed from black powder to this gray-yellow powder, and finally it was handed over to one of Chen Shuren's personal guards for a test firing.
Chen Shuren watched the whole process with rapt attention, until the last moment when the fire was fired. Under several roars that were slightly different from those of black gunpowder, a slight amount of white smoke dispersed, but it was definitely much smaller than the smoke of black gunpowder.
Moreover, the flame of an open flame is smaller than that of black powder. The muzzle flash of the muzzle is much shorter and faster. You can see the flame, but it is not like black powder directly spitting out fire.
All this shows that the new charge is much stronger than black powder in terms of deflagration rate and gas expansion rate, so it can deflagrate so fully and completely that it can be completed instantly.
Obviously, as a new type of propellant, this gray-yellow powder is very qualified. The small amount of smoke that still remains is probably due to insufficient purity, poor control during the reaction, and impurities incorporated into the carbonization.
These problems are not major. It will be acceptable to give it a few months or even a year and a half to slowly optimize and improve, and even continue to learn experience in actual use and provide feedback and modifications while using it.
Chen Shuren was just curious: Where did Fang Yizhi and the others get the concentrated nitric acid?
Adding nitric acid to cotton is a step that everyone on earth can do, but nitric acid itself was not easy to do in ancient times.
…
A quarter of an hour later, in the laboratory of the Gunpowder Bureau, everything was finally revealed and the mystery was revealed.
And Shen Shuren had to admire that the ancient people were actually very good at chemical practice, what they lacked was just a systematic theoretical summary.
Fang Yizhi showed him a pile of experimental equipment and threw him an ancient book as if to show off.
"This is the notebook of Sun Simiao, the miracle doctor of the Tang Dynasty. It can be regarded as a fragment of Qianjin Prescription. It mainly records Sun Simiao's verification of the actual medicinal value of some of the minerals used by Ge Hong in the Eastern Jin Dynasty to make elixirs.
This is what Mr. Song found out. When you mentioned that you need to use saltpeter and other strong acids to make a new acid, Mr. Song tried it for a while and then doubted that the acid you said the Hongyi people used was saltpeter and green acid.
The product of alum-oil reaction.
Green vitriol oil was recorded by Ge Hong in the Eastern Jin Dynasty, but he did not say how to prepare green vitriol oil or how to obtain it. He only said that there is such a thing and it is hard to find.
Sun Simiao of the Tang Dynasty went a step further and wrote in his medical prescription notes that green vitriol oil can be obtained by calcining green gall vitriol and adding other vitriol to absorb the burned essence. So Mr. Song and I followed this idea.
At first, I tried dozens of times, but couldn't figure it out. Later, I found that there seemed to be differences in the ancient and modern records of 'green vitriol' and 'green bile vitriol', so I looked for it from many sources.
Green vitriol and green vitriol-like minerals were calcined and compared with the products. Only then did we know where the misunderstanding between Sun Simiao and Ge Hong was——
Green vitriol and green gall vitriol are not just the same thing. Some can produce green vitriol fumes after calcination, while others cannot be burned, or the poisonous gas produced is only similar to the smell of ordinary sulfur burning.
, can not burn green vitriol fumes. We tried repeatedly and found the green vitriol that can be used - I also decided to record the green vitriol and green vitriol separately from now on. Green vitriol and bile vitriol should be completely different.
Some of the gall vitriol turned green, but it was just mixed with impurities."
After hearing this analysis by Fang Yizhi, Chen Shuren was really in awe.
Even though he had studied middle school chemistry in his previous life, it took him a while to confirm Fang Yizhi's discoveries in his mind one by one.
The green vitriol and green bile vitriol mentioned by the Ming Dynasty should include ferrous sulfate and impurity-containing copper sulfate - pure copper sulfate crystals should be aqua blue. Anyone who has studied junior high school chemistry knows this, but in nature
Copper sulfate is easy to be mixed with impurities, especially yellow impurities such as natural sulfur. When yellow and blue are mixed, it turns green, which is normal.
So much so that in the Tang and Song Dynasties and even until the Ming Dynasty, the ancients did not know that ferrous sulfate and copper sulfate containing sulfur impurities were not the same thing. When alchemists burned green vitriol and bile vitriol, the products they produced were different every time.
They themselves can't explain it.
From Ge Hong, the great alchemist of the Eastern Jin Dynasty, to Sun Simiao, the miracle doctor of the Tang Dynasty, they all recorded the burning of these alums, but they did not know that they were burning several different things.
Ferrous sulfate can of course be calcined to produce sulfur trioxide gas, which can then be absorbed using a special process to obtain sulfuric acid, which is the "green vitriol oil" recorded in ancient books.
Once you have sulfuric acid, it is easy to make nitric acid. You can directly react sulfuric acid with saltpeter or other nitrates. It is best to produce sulfate precipitation, so that what is left is nitric acid.
The specific process is a bit complicated, but after all, it is a technology that has been mastered by the ancients. There is nothing to elaborate on. The most critical step is to create sulfuric acid out of thin air in an environment without strong acid.
Shen Shuren was originally limited by his thinking, because modern industrial mass production of sulfuric acid basically involves directly burning sulfur to produce sulfur dioxide, then adding a certain catalyst to further oxidize it to sulfur trioxide, and then absorbing it. This is very efficient.
The raw materials used are also cheap, and sulfur is everywhere.
Even in modern industry, in order to control excessive sulfur dioxide emissions, many factories that emit sulfur-containing waste gas directly add catalysts to the waste gas treatment process to oxidize it into sulfur trioxide and then absorb it into sulfuric acid. The sulfuric acid is directly an environmentally friendly waste gas treatment product, and it is extremely cheap.
Not necessary.
But Chen Shuren traveled back to the late Ming Dynasty, and he could not simply perform the operation of "further catalytic oxidation of sulfur dioxide gas into sulfur trioxide", so he still could not figure out how to industrially produce hexavalent sulfur and sulfuric acid.
Unexpectedly, Fang Yizhi and Song Yingxing did not think about "industrial mass production" at all. They chose to directly calcine sulfur trioxide gas from readily available hexavalent sulfate in nature, and then absorb it into sulfuric acid.
The advantage of this is that you no longer have to worry about how to catalytically react tetravalent sulfur into hexavalent sulfur. The sulfur in sulfate itself is hexavalent.
The disadvantage is that it puts forward very high requirements for production raw materials - if industrialized large-scale production is used, sulfuric acid or even sulfur-containing waste gas can be directly used to produce sulfuric acid, which is extremely cheap. Now we need to look for ferrous sulfate minerals, and the raw materials are expensive.
How many times.
It is impossible to rely on the small output of calcined ferrous sulfate to supply propellant for large-scale musket units. At most, it can only supply the most elite troops or personal guards.
Chen Shuren briefly asked about the cost of this sulfuric acid, and it turns out that it is very expensive. It is more than ten times more expensive than burning sulfur directly. In other words, the cost of the sulfide used is at least more expensive than the sulfur used in black gunpowder.
More than ten times.
In terms of the cost of using nitrate, it is at least several times more expensive than saltpeter for black gunpowder. Anyway, because of the complex reaction links in the middle, the reaction rate of nitrate is relatively low, and there is loss in every reaction.
All in all, the current manufacturing cost of this nitrocellulose smokeless gunpowder is about eight to ten times that of black gunpowder!
In the future, if we can directly use sulfur-containing waste gas or sulfur combustion to produce sulfuric acid, and improve the utilization rate of nitrate, we can reduce the cost to one-third or even one-fourth under the current situation. In that case,
, the production cost is still two to three times that of black powder.
"No matter, it's a bit expensive, but it's a good thing if you can make something first. We can think of ways to reduce costs later. This batch of gunpowder will be used by my bodyguards first.
For now, all of them will be used by the revolver team. After all, revolvers are the most precise and have the highest requirements for controlling propellant residue and leakage. In the future, if cheaper ones become available, they will be used by the pike team."
Chen Shuren quickly figured out how to deploy this new propellant.