In fact, Liu Yun had already obtained a lot of coarse salt by distilling seawater.
These coarse salts were not in granular form, but in lumps, and were collected by Liu Yun in an empty bottle.
"Xiaoyun, these salts are so strange."
Wang Qianqian looked at the salt that was completely different from usual. While asking, she pinched a little bit with her hands and put it in her mouth.
Bah bah bah...
As a result, Wang Qianqian just put it in her mouth, and before she could taste it properly, she spit it out with all her strength, and the expression on her face was distorted.
"Why does this salt taste like this?" Wang Qianqian continued: "Although it is salty, why is it still bitter? It is so unpalatable."
"That's what kosher salt is."
Zhao Qian also pinched a little and tasted it. The taste was indeed not good. "There are not only salts in seawater, but also many other impurities. Distilling seawater will only lose water. These impurities cannot be removed."
Liu Yun took Zhao Qian's words and said: "Long-term consumption of such coarse salt is not good for the body and needs to be purified."
Wang Qianqian asked: "How to purify it?"
"Although asking questions when you don't understand is a good learning quality, you are only a junior high school student. Even if I tell you the method, do you understand it?" Zhao Qian immediately said dissatisfied when he saw that Wang Qianqian kept asking questions and delayed Liu Yun's work progress.
"You're just a high school student, so what's there to do?" Wang Qianqian retorted.
"I have higher education than you."
Zhao Qian puffed up his chest and exuded the unique temperament of a high school student. Then he immediately bent down and looked at Liu Yun and said, "Let's ignore the junior high school students. Please show me how to purify sea salt."
A certain talented student from Peking University looked at the quarreling high school students and junior high school students and nodded slowly.
Liu Yun took a bottle of fresh water she purified herself, crushed the coarse salt into particles, and began to add it to the fresh water. She did not stop until the added coarse salt particles no longer dissolved.
Seeing this scene, a high school student and a junior high school student had puzzled expressions on their faces. They didn't understand why the talented students from Peking University added salt to the fresh water they had finally purified.
Doesn’t this turn fresh water into sea water again?
Just when they were confused, Liu Yun found some clothes to use as a filter and covered the mouth of the bottle layer by layer. After covering three layers in a row, some black powder was added to the fourth layer.
A junior high school student didn't know what black powder was, but a high school student knew that these black powders were charcoal powder.
When surviving in the wilderness, charcoal powder has many uses. One of them is to absorb harmful substances in the water or air. It should be used to absorb impurities in sea water.
Of course, this method can only remove impurities that are insoluble in water, and has no effect on impurities dissolved in water.
Liu Yun added three more layers of clothes, then turned the mouth of the bottle downward, and soon water dripped out through the layers of clothes and charcoal.
The whole process was very long, and it took a lot of time to filter all the salt water in the bottle.
When I uncovered the clothes on the bottle mouth, I found that there were a lot of impurities left on the clothes. The innermost layer had the most impurities, and the number decreased gradually. The last layer had almost no impurities left.
"This step is to remove water-insoluble impurities in the brine. If conditions permit, you can do it several times." Liu Yun took the initiative to explain when she saw the expression of a junior high school student who wanted to ask but didn't dare to ask.
After Liu Yun finished explaining, she brought an empty bottle again and poured out half of the freshly filtered salt water.
Then, put half of the salt water on the fire for distillation and heating...
As the water in the brine evaporated, crystals began to appear at the bottom of the bottle. This time, both high school and junior high school students knew that these were salts.
Compared with the coarse salt at the beginning, the salt this time is much finer and the color is much whiter.
"Xiaoyun, are these salts that can be eaten directly after purification?" Wang Qianqian asked.
"This is just the first purification. Although it is better than the first time, it is best not to eat it directly." Liu Yun shook her head and said.
"It's not edible yet, it's so troublesome." Wang Qianqian said.
"Don't worry, it's already going very quickly." Liu Yun said.
After saying that, Liu Yun crushed the salt purified this time and brought the remaining half bottle of salt water.
Under the shocked eyes of high school students and junior high school students, the talented student from Peking University poured all the coarse salt that had been purified once into half a bottle of salt water and kept stirring.
However, a magical scene occurred. This time, the coarse salt did not dissolve in the water, but remained in the form of crystals at the bottom of the bottle.
After stirring for enough time, Liu Yun poured out the salt water and heated the crystals remaining at the bottom of the bottle.
Because there was not much water this time, the distillation step was quickly completed and salt was obtained again.
They just didn't know if there was something wrong with their eyes or if the purification was really useful. Zhao Qian and Wang Qianqian were shocked to find that the salt purified this time was whiter.
"Have a taste!"
Liu Yun placed the twice-purified salt in front of Zhao Qian and Wang Qianqian.
"I'll go first!"
Wang Qianqian pinched a little bit with her hands and put it into her mouth without hesitation.
After tasting it carefully, she said in disbelief: "It's amazing. The salt this time doesn't have much bitterness. Xiaoyun, how did you do it?"
Zhao Qian also looked over with a puzzled face. He didn't understand what was going on.
Liu Yun did not hide her secrets, and explained with a smile: "The first step of purification is to remove impurities that are insoluble in water...The second step of purification is to remove impurities that are soluble in water."
"It's just that because we don't have enough conditions now, I use the saturation purification method... Do you understand what saturation is?"
Wang Qianqian shook her head and said she didn't know.
Zhao Qian frowned and thought, and said: "Is this the maximum limit for a substance to dissolve in water? If you continue to add this substance, it will no longer dissolve."
"Roughly the same!"
Liu Yun said: "In the beginning, I kept adding coarse salt to the fresh water. The purpose was to make the salt water saturated. At this time, if I continue to add salt, what will happen?"
"When it is saturated, it will naturally become insoluble."
After Zhao Qian finished his answer, he suddenly had a flash of inspiration and suddenly realized: "The saturation of each substance is different. The salt water just now only has the maximum saturation of salt, but other water-soluble substances in the coarse salt have not.
Reaching saturation.”
"So, add coarse salt again, the salt is insoluble in water, and other impurities are soluble in water, so the salt you get is more refined."
After listening to Zhao Qian's words, Liu Yun smiled and said: "Yes, that's the truth. You are very powerful."
When Zhao Qian received Liu Yun's praise, he immediately felt a sense of superiority as he was praised by the teacher. He glanced sideways at the junior high school student next to him and raised his head high.
That look seems to say, junior high school students, have you ever felt overwhelmed by academic qualifications?
"childish!"
Wang Qianqian snorted and turned her head away, with a look on her face that said she was not as knowledgeable as Doubi.
But her clenched fists showed that she was very unhappy now.