Chapter 166 (2/2)

Chinese ancestors invented black powder a long time ago. It is precisely because the invention of black powder has changed the world war pattern, so black powder is also recognized as one of the four great inventions of China all over the world.

The origin of black powder can't be studied, but there's no doubt that when those Chinese alchemists were thinking about how to make pills, they inadvertently put the purified potassium nitrate, sulfur and charcoal together, and the proportion of these three raw materials was quite similar. As a result, the world's first black powder broke out.

Among the three raw materials of black powder, nitre is undoubtedly the most important. The niter used to make black powder is actually potassium nitrate.

However, there are a lot of impurities in both the nitrate soil produced in the nitrate field and the nitrate stone produced in the nitrate mine. If these impurities are not removed, the power of black powder will be greatly reduced.

Maybe a few hundred years ago, this kind of black powder had little power, but now, before other kinds of powder were invented, the power of black powder was directly related to the range and power of muskets and artillery. Therefore, at this time, when making black powder, we should not only strictly follow the best proportion, but also purify the raw materials, Only in this way can the power of black powder reach the maximum.

It's like the rock salt in xiaoyanshan. If it's not purified, people will die if they eat it.

If the niter produced in this kind of niter ore is not purified, the black powder will become a joke.

After the nitre came back, the stone bear began to command the people to purify nitre.

In fact, it's not difficult to purify high-purity potassium nitrate from niter. As a puppet fan, Shi Xiong knew how to purify niter.

The first thing to do is smash. This is similar to salt making, that is, first crush the saltpeter, and then grind the crushed particles to be finer, the finer the better.

At the same time of crushing the saltpeter, we also need to prepare plant ash.

This plant ash is the key thing. Whether we can purify high-purity potassium nitrate depends on plant ash.

Because there is no chemical experimental instrument, the stone bear can't identify whether these nitrates from Xiaohe tribe are sodium nitrates or potassium nitrates, but it's absolutely right to add a certain proportion of plant ash when purifying them, no matter whether they are sodium nitrates or potassium nitrates.

Because the main components of the plant ash are potassium carbonate and potassium sulfate, the potassium ion in the plant ash will replace the sodium ion in the nitrate soil after the plant ash and the nitrate are put together to form potassium nitrate. In addition, carbonate ion and sulfate ion in plant ash combine with calcium and magnesium ion in nitrate soil to form insoluble salt and precipitate, so as to remove calcium, magnesium and other impurities.

In fact, the process of purifying sodium nitrate is a series of basic chemical reactions.

Of course, plant ash can not be used casually. The best plant ash is the ash obtained by burning buckwheat stalk, cotton hull, cotton stalk, broad bean stalk, vegetable stalk, tomato stalk, sorghum stalk, corn stalk and other plants, and the potassium content can reach 10-15%. Although other plant ashes can also be used, the effect is not ideal.

There's a lot of corn stalks in the tribe, so it's just a big fire.

Put the ground powder and black plant ash into a large pot at the ratio of 8:1, and then add water. When you add water, you can't add cold water. Instead, you need to add hot water with a temperature of about 75 degrees centigrade. The amount of water can't exceed these materials.

After hot water is added in, the material begins to dissolve. Because of plant ash, a pot of water is black.

The people of the tribe are very happy for the guardian to ”change the play” with the people of the tribe, because all the people know that once the guardian starts to change the play, the tribe can get a good thing.

The first time the guardian changed his play, there was a lot of refined salt in the tribe

This time, the guardian wants to change his play. Naturally, the people of the tribe respond with a bang.

Therefore, although there is a pot of black hot water now, there is nothing strange about them. The reason why changing drama is changing drama is that it is a process of making the impossible possible. In this process, all kinds of unpredictable phenomena will naturally appear.

After adding hot water to the pot, the stone bear asked the two people to keep stirring with spoons, so as to fully dissolve the plant ash and saltpeter in the water.

Stirring takes at least 15 minutes. After mixing, the dissolved in water are dissolved in water, insoluble in water will naturally become sediment.

Then the black water starts to filter.

There are many such things as funnel and filter cloth in xiaoyanshan. Any one of them will be enough to cope with filtration.

The black water is filtered out through the filter cloth and funnel, and the remaining residue is isolated. This black water is nitrate water.

Pour the nitrate water into another large pot and start to boil. This step is also called boiling nitrate.

When boiling nitrate, keep stirring to prevent bottom sticking and splashing.

With continuous heating and stirring, the nitrate water in the pot will continue to evaporate. When about two-thirds of the water evaporates, the solution has become viscous.

At this time, the stone bear sticks with a bit of sticky solution, the result of this solution out of the pot immediately condensed into a ball. The change made the bear nod with satisfaction, and then ordered the pot to be lifted aside to cool naturally.

In the process of boiling nitrate, the temperature is always very high, and at this temperature, the solubility of potassium nitrate will become very large, so it will not precipitate. On the contrary, impurities such as sodium chloride and potassium chloride are precipitated because of their low solubility at high temperature.

However, the solubility of potassium nitrate solution will decrease rapidly with the decrease of temperature until it is naturally cooled to 30 ℃. At this time, the solubility of potassium nitrate agriculture will change the most due to the influence of temperature, and the decrease of temperature will make a large amount of potassium nitrate precipitate rapidly. However, at this temperature, the solubility of sodium chloride and other salts will become very small and will not be separated out.

At this time, the solid obtained by filtration is potassium nitrate crystal.

In fact, this process is a chemical reaction + physical change process. Potassium ions in plant ash are used to replace sodium ions, and then potassium nitrate is formed. With the help of different solubility of various salts at different temperatures, pure potassium nitrate crystals are finally precipitated.

Of course, the purity of primary purification may not be so high, but it doesn't matter. It's a big deal to carry out the same operation on the precipitated potassium nitrate crystal again and carry out secondary purification.

As long as it is not too troublesome, potassium nitrate crystal with high purity can be obtained by this method.

In fact, in this era, Europeans also used this method to purify potassium nitrate on a large scale. It's just that they don't use saltpeter, but they use the saltpeter mixed with human and livestock urine in the saltpeter field to purify