When he got up early the next morning, he went to the kitchen and looked at yesterday's salt water, and there was a layer of charcoal floating on the surface of the salt water. He gently brushed away the charcoal floating on the surface with his hand, and the salt water inside had become clear.

He found a large funnel, washed a piece of burlap and stuffed it at the bottom, then compacted some soft straw on top, spread a layer of charcoal, and spread another layer of kneading and softened straw on top, and the whole funnel was almost full. Finally, a piece of numb was covered on top, tied with a straw rope, and a simple filter device was ready.

After the preparations are done, eat breakfast first.

After breakfast, Jia took out the precipitated brine water, fished out the charcoal floating on the surface, and carefully poured the clear brine on the surface into another wooden barrel, leaving a lot of sediment and sinking charcoal at the bottom.

He brought the prepared funnel and filtered salt water to Yao Lao, ready to continue at the teacher's house. After Yao Lao saw his preparation, he didn't say anything, and he also wanted to see what Jia Yi could come up with.

After all, Kaichi's preparation looks very well-prepared.

Jiayi moved all his things to the yard where he usually dried medicinal herbs.

He poured water from above the funnel, and from under the funnel came a black stream of charcoal water, which was so thin that he could only add water slowly, or it would overflow from the top of the funnel. When the water cleared, he took the funnel to a new barrel.

He slowly poured the preliminarily treated brine into the funnel, watching the clear water flow under the funnel slowly fall, and after a while, he finished filtering the brine water, and the filtered brine could no longer see a single impurity, it was as clear as spring water.

I dipped my fingers in the salt water and tasted it, only I felt that there seemed to be no difference between the salt I usually ate and the salt I usually ate, but Kaichi knew that it wasn't yet.

When Yao Lao saw it, he also came over to taste it, his eyes lit up, and he seemed to be startled, and he looked at Jia Yi deeply, but he didn't speak.

After the brine filtration and purification is completed, it is time to boil the salt. There is no trick to this step, just set up the pot, pour the salted water into it, and boil it over a fire.

After the brine is boiled, continue to boil until most of the water has evaporated, and the crystal salt grains have precipitated out one by one.

Seeing that it was almost cooked, Kaichi stopped the fire, and at this time there was still a thin layer of water left in the pot, about a finger's width deep.

Jiayi used a relatively fine cloth to pour everything in the pot while it was hot, and filtered out the water in the pot. This filtered layer is brine, which contains magnesium chloride, potassium chloride and other impurities that dissolve in water.

Because salt sodium chloride generally contains magnesium chloride, potassium chloride and other products, because mineral salts are toxic, it is likely to contain nitrite.

Nitrite is a highly toxic substance, on the earth, adults can cause poisoning if they ingest 0.2-0.5 grams, and 3 grams can cause death. Nitrite is also a carcinogen, according to research, esophageal cancer is positively correlated with the amount of nitrite ingested by patients, and the carcinogenic mechanism of nitrite is: nitrite reacts with secondary amines, tertiary amines and amides in food in the environment of gastric acid to form strong carcinogen N-nitrosamines. Nitrosamines can also enter the fetus through the placenta and have a teratogenic effect on the fetus.

Even if the human body in the other world is more resistant, long-term consumption of salt containing nitrite can still cause poisoning and even death. However, it has little to do with cancer, because civilians rarely live to the age of cancer, and even if cancer does, it may not wait for the outbreak to cause death.

The age of high incidence of cancer is 40~70 years old, and in ancient times, the average age was only thirty or forty years old, both Chinese and foreign. It's clear that most people don't live to the age of cancer.

Jiayi poured out the last brine, because the content of sodium chloride in the brine is the highest, and it will be precipitated from the water first, and the content of those magnesium chloride nitrite is low, and most of them have not yet reached the level of precipitation, and the solubility of sodium nitrite is high at high temperature, while the solubility of sodium chloride in table salt does not change much with temperature.

In the end, most of the toxic substances such as sodium nitrite in the brine are filtered out with the brine, and the rest is relatively pure table salt. In order to prevent any residue, Kaichi poured water on the side of the obtained salt and rinsed it, although some of the salt will be lost, but the salt obtained is undoubtedly purer and safer.

In the end, Kaichi got about three pounds of salt, which is about four pounds in this unit. He carried back about seven or eight catties of salt mines (and herbs or something, about 10 catties in total), and later, although Yao Lao still took him to look for herbs, he carried them all by himself.

In the end, the seven or eight catties of salt mine only got more than 3 catties of salt, and even if the loss was added, the highest salt content of the ore he brought back was only about six or seven percent. However, the salt mine he brought back was carefully selected to contain large chunks of salt, and it is estimated that the salt content of ordinary salt mines is less than half.

This content is really not high, it is considered a poor mineral. On the earth, salt ores can be divided into three categories according to their grades: rich ores with sodium chloride content greater than 85%, medium ores with sodium chloride content of 50%~85%, and poor ores with sodium chloride content of 20%~50%.

As for less than 20%, it is called salinized land, not mineral.

Jiayi took the prepared salt to the medicine and looked at it, only to see that the salt was white and clean, and if you looked carefully, each grain was crystal clear, and there was no impurity, not even a little variegation. The snow salt sold in the town, although it is named after snow, is actually yellowish.

Yao Lao dipped a little salt with his fingers, licked it lightly with his tongue, and tasted it carefully in his mouth, only to feel that the salt taste was pure, without the slightest miscellaneous taste, and there was no dregs left. If you are not careful, you can always eat grains of sand or something. And it seems to be more salty, and I don't know if it's an illusion brought by appearance.

"This is what you refined from salt ore?" he looked at Jia Yi, his eyes were complicated, and he felt that his three views were a little shaky.

In fact, if you think about it carefully, there have been many geniuses on the earth, ancient and modern, and there are also legendary geniuses in this world, it is said that the sage of Liai in the north of the empire, born in a family of barons, can barely maintain the dignity of the nobility, he can read and write at the age of three, and when he was 7 years old, he refuted his teacher, and no teacher is willing to teach him since.

But he gradually became famous by self-study, traveled all the way to the world, visited all kinds of famous teachers and wealthy families, borrowed their collections, and became a little sage at the age of 17, and became a recognized sage at the age of 20. When he was 22 years old, he thought about who I was, where I came from, where I was going, and what was the meaning of life.

In addition to the sages of Liai, there are many geniuses in the history of this world, and even if you get rid of the mythical ones, you can't count them on two hands. In addition to these, there are many more young geniuses who have become injured Zhongyong and failed to leave a name in history.

However, when a genius really appeared in front of him, his feelings were still very subtle, a little bit of a squeeze, and this D person was hanging. Of course, Yao Lao didn't know what Kaihang was, but it felt the same.

Yao Lao knew that he had asked a nonsense, and he watched him boil the salt, although many of the steps were not very clear, but the result was still very clear.

"Jiayi, don't take this salt out, remember, you must not take out this salt!" Yao Lao's words were very serious, word by word.

"I know, teacher. I'm not going to mess around. Jia Yi assured that he suddenly thought of something and said to Yao Lao, "Teacher, I'll go home and get something." ”

After saying that, Jia Yi ran home, Yao Lao looked at his back, and he didn't know whether it was good or bad.