Absorbent cotton has a better dressing and hygiene effect than ordinary cotton, and the principle is obviously because some of the oil and protein components in ordinary cotton are not required by the dressing material.

Oils and proteins are easy to be decomposed and utilized by bacteria and turned into "medium and nutrient solution" for cultivating bacteria and viruses, so medical cotton should be defatted and deproteinized as much as possible, leaving purer cellulose.

However, the cotton requirements for making nitrocellulose are obviously different from those of medical cotton.

Some of the components that are removed from medical cotton are needed when making nitrocellulose. If you take it off too cleanly, it will cause the reaction to fail.

Therefore, when seeing Fang Yizhi's medical absorbent cotton, Shen Shuren was glad about this invention at the same time, but also had more hidden worries, thinking that the research and development of nitrocellulose had temporarily fallen into the wrong way.

Fortunately, Fang Yizhi knows him too well, just looking at the change in his expression, he knows what he is depressed about, originally Fang Yizhi still wanted to sell a pass, but now he directly told him:

"Brother Xian is really knowledgeable, don't you also know that medical cotton and nitrified cotton have different requirements for raw materials?"

When Shen Shuren heard this, he couldn't help but be overjoyed, and he had some expectations: "Why do you say 'also'?" That's what you already know? Mr. Song also knows? Could it be that you have made both kinds of cotton? ”

Fang Yizhi showed a smug expression at this time: "That's natural, it's not difficult." When dealing with absorbent cotton, it may be that the lime alkali surface is used too much, and the things that come out are indeed missing a lot of useful ingredients.

But since we know the truth, and we also know that the scholars of the Hongmaoyi people have used this idea to create cotton wool, we can try and change it repeatedly, and we can still ponder whether we understand this thing for a few months? ”

Shen Shuren finally felt a little awe-inspired: this party is very wise, and he was dialed by himself, is this realization, he can understand the rough principle of acid-base balance, and get 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 for the time being, just based on this experience, it will definitely be of great help to the chemical development of this era.

Still a little anticipating, he asked, "So...... In the end, you have tried, which pre-treated cotton is suitable for acidification? So how did you do the experiment, did you come up with that strong acid made from saltpeter? ”

Fang Yizhi didn't speak, 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, but by no means charred black, unlike what the Sinking Tree Man had imagined.

It may also be that Shen Shuren did not have a solid understanding of chemistry in his previous life, or he saw 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 the nitrocellulose was also black.

In fact, nitrocellulose is grayish-yellow, which is not exactly the same color as the primer of modern bullets, and there are some other ingredients doped in the modern primer.

On the other hand, in the early production and manufacturing of nitrocellulose, if there is black, it is generally too violent, the heat and heat dissipation control is not good, the temperature is carbonized, and impurities are mixed.

The nitrocellulose that Fang Yizhi is showing at this moment is obviously not pure, and with the level of science and technology at the end of the Ming Dynasty, it is impossible to make it too pure.

Shen Shuren took it in his hand and carefully observed it, but he couldn't tell the authenticity, so he had to let someone take a little bit and use it to be loaded into a bullet for test firing.

Fang Yizhi was also prepared, and immediately asked someone to bring a revolver produced by Daye Military Factory, as well as a breech-loading short-barreled double-barreled spray, and then demonstrated on the spot, asking a henchman to change the charge in the paper bullet case from black powder to this gray-yellow powder, and finally handed it to a guard next to Shen Shuren, and shot for a test shot.

The Shen Shuren watched the whole process with full attention, until the moment of the final firing, under a few roars that were slightly different from the black powder, a slight white smoke drifted out, but it was definitely much smaller than the smoke of the black powder.

Moreover, the flame of the open flame is also smaller than that of black powder, and the muzzle flame of the muzzle is much shorter and faster, and the fire can be seen, but it is by no means the appearance of black powder spewing fire directly outward.

All this shows that the new charge is much stronger than the black powder in terms of deflagration rate and gas expansion rate, so that the deflagration can be so fully and completely completed in an instant.

Obviously, as a new type of propellant, this gray-yellow powder is very qualified. There is still a small amount of smoke left, which should be just not pure enough, the reaction is not well controlled, and the carbonization is mixed with impurities.

These problems are not big, and it is acceptable to give a few months or even a year and a half, slowly optimize and improve, and even continue to learn from experience in actual use, and make changes while using feedback.

Shen Shuren was just curious: where did Fang Yizhi get the concentrated nitric acid from?

Add nitric acid to cotton, this step will be done by everyone on the earth, but nitric acid itself is not easy to do in ancient times.

……

A quarter of an hour later, in the laboratory of the Gunpowder Bureau, the truth was finally revealed and the mystery was revealed.

And Shen Shuren also had to admire that the ancients actually had a hand in chemical practice, and what they lacked was only a systematic theoretical summary.

Fang Yizhi showed him a bunch of experimental equipment while throwing him an ancient book as if he were ostentatious.

"This is the note of Sun Simiao, a miracle doctor in the Tang Dynasty, which can be regarded as a fragment of a thousand gold prescriptions, mainly to record Sun Simiao's verification of some minerals used by Ge Hong in the Eastern Jin Dynasty for alchemy, and the actual medicinal value.

This is what Mr. Song found out, when you mentioned that you want to use saltpeter and other strong acids to make a new acid, Mr. Song tried it for a while, and then he suspected that the acid you said about the Hongyi people was the product of the reaction between saltpeter and alum oil.

Alum oil was recorded by Ge Hong in the Eastern Jin Dynasty, but he didn't say how to make and get it, only that there was such a thing, and it was hard to find.

Tang Sun Simiao went one step further and wrote in the notes of the medical book prescription that green gallium is calcined, and some other alum is added to absorb the essence of its burning, and green alum oil can be obtained, so Mr. Song and I groped along this line of thought.

At the beginning, I tried dozens of times, but I couldn't get the essentials and couldn't do it, but later I found that it seemed to be the records of 'green alum' and 'green bile alum' in ancient and modern times, and there were many differences in cognition, so I found a variety of sources of green alum, as well as minerals that resemble green alum, and calcined them and compared their products, so I knew where the misunderstanding between Sun Simiao and Ge Hong was-

The green alum and green gall alum in the world should not be just one thing, some can get the green alum fume after calcination, and some can't burn it out, or the poisonous gas burned out is only similar to the smell of ordinary sulfur burning, and it can't burn the green alum fume. We tried and tested before we found a usable alum – and I decided to keep it separate from the green gall from now on. Green alum and bile alum should be completely different things, some bile alum is green, but mixed with impurities. ”

Fang Yizhi's analysis, after hearing it, really made Shen Shuren awe-inspired.

Rao studied middle school chemistry in his previous life, and it took a while for him to confirm Fang Yizhi's discoveries in his mind.

The Ming Dynasty people said that green alum, green bile alum, there should be ferrous sulfate, there are also impurities of copper sulfate - pure copper sulfate crystals should be water blue, this has studied junior high school chemistry knows, but the natural copper sulfate is easy to mix with impurities, especially yellow impurities such as natural sulfur, yellow and blue mixed green, it 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 those alchemists burned alum and gall alum, the products produced were different every time, and they themselves could not explain it.

From Ge Hong, the great alchemist of the Eastern Jin Dynasty, to Sun Simiao, a divine doctor in the Tang Dynasty, they all recorded calcining these alums, but they didn't know that they were burning several different things.

Of course, ferrous sulfate can be calcined to produce sulfur trioxide gas, and then absorbed by a special process to obtain sulfuric acid, which is the "green alum oil" recorded in ancient books.

After having sulfuric acid, it is easy to make nitric acid, directly take sulfuric acid and saltpeter or other nitrate and then react, it is best to produce sulfate precipitation, so that the rest is nitric acid.

The specific process is a bit complicated, but after all, it is a technology that the ancients have mastered, and there is nothing to repeat, and the most critical step is to produce sulfuric acid from nothing in an environment without strong acid.

Shen Shuren was originally limited by his thinking, because the modern industrial production of sulfuric acid is basically directly burned with sulfur dioxide, and then a certain catalyst is added to further oxidize sulfur trioxide, and then absorbed. This is very efficient, the raw materials used are cheap, and sulfur is everywhere.

Even in order to control the excessive sulfur dioxide emissions in modern industries, many factories that emit sulfur-containing waste gases directly add catalysts in the waste gas treatment process to oxidize sulfur trioxide and then absorb it into sulfuric acid. The sulfuric acid is directly an environmentally friendly waste gas treatment product, and it is so cheap that you don't want it.

However, Shen Shuren traveled back to the end of the Ming Dynasty, and he could not simply come up with the operation of "further catalytic oxidation of sulfur dioxide gas to sulfur trioxide", so he couldn't think of how to industrialize the production of hexavalent sulfur and sulfuric acid.

Unexpectedly, Fang Yizhi and Song Yingxing didn't think about "industrial mass production" at all, he chose to calcine sulfur trioxide gas directly from the hexavalent sulfate that is readily available in nature, and then absorb it into sulfuric acid.

The advantage of this is that you no longer have to worry about how to catalyze the reaction of tetravalent sulfur into hexavalent sulfur, and the sulfur in sulfate itself is hexavalent.

The disadvantage is that it puts forward high requirements for the production of raw materials - if it is produced on a large scale by industrialization, it is required to directly produce sulfuric acid from sulfur or even sulfurous waste gas, which is extremely cheap. Now I have to look for ferrous sulfate minerals, and I don't know how many times more expensive the raw materials are.

It is unlikely that the small production of ferrous sulphate calcination will supply a large number of musket troop propellants. At most, it can only supply the most elite troops, or personal guards.

Shen Shuren briefly asked about the cost of this sulfuric acid, and it was indeed very expensive, more than ten times more expensive than burning sulfur directly. In other words, the cost of sulfide used is at least ten times more expensive than that of black powder.

In terms of the cost of nitrate, it is at least several times more expensive than saltpeter for black powder, anyway, because of the complex reaction link in the middle, the reaction rate of nitrate participation is relatively low, and there is a loss in every reaction.

All in all, this nitrocellulose smokeless gunpowder is currently about eight to ten times more expensive to manufacture than black powder!

In the future, if we can directly use sulfuric acid to produce sulfuric acid from sulfurous waste gas or sulfur combustion, and improve the nitrate utilization rate, it can reduce the cost to one-third or even one-quarter in the current state. In that case, the production cost would still be two to three times that of black powder.

"No matter, although it is a little expensive, it is a good thing to be able to make things first. Process and reduce costs, you can slowly think of a way. This batch of gunpowder will be used by my guards first.

At present, all of them are used by the revolver team, after all, the revolver is the most precise, and the control requirements for propellant residues and leakage are also the highest. ”

The Sinking Tree Man quickly figured out how to deploy the new projectile.