After it took more than a month to complete the surveying and mapping of the ditch and the construction of the dam was formalized, Chen Xian was relieved to let go of the second engineering team and began to devote most of his experience to experimentation and design.

……

As the mapping of the irrigation system nears completion, there is good news from the treatment of dermatological diseases.

After more than half a month of treatment, the symptoms of that group of patients disappeared completely.

After a period of consolidation and observation, the scabies did not recur again, and Chen Xian accepted these people.

The success of this experiment made Chen Xian very excited, which shows that he already has an effective process to deal with one of the most troublesome diseases of this era, scabies.

……

The saponification reaction is not complicated, in fact, it is a chemical reaction of oil and oil under the action of a strong alkali to produce sodium/potassium salts of fatty acids and glycerol.

This chemical reaction is also not demanding on external conditions, and can be carried out at room temperature, or it can be slightly heated to speed up the reaction.

The handmade soap that can be seen everywhere today is soap made under the conditions of a family workshop using the principle of saponification reaction.

The production of handmade soap is usually made with vegetable oil such as olive oil, adding caustic soda, that is, sodium hydroxide, and stirring for a certain period of time, you can get a viscous soap paste, and then after inverting the mold, it is handmade soap.

Grease is easy to find, but sodium hydroxide is nowhere to be found.

Fortunately, the Internet writer's information contains several methods of making soap. Ammonia water is used to replace strong alkali, and plant ash solution is used to replace strong alkali.

Chen Xian feels that for himself, the more reliable method is to use plant ash solution to extract potassium carbonate and sodium carbonate by boiling precipitation, and then react with potassium carbonate, sodium carbonate and lime aqueous solution to obtain potassium hydroxide and sodium hydroxide strong alkali.

The advantage of this method is that potassium hydroxide and sodium hydroxide with high purity can be obtained, and it is easier to control the ratio of materials in the subsequent saponification reaction.

The grass ash and lime used in this method are easy to find, and limestone is one of the common building materials of this era, lime was used in the construction of the brick houses in the new Zhuangzi, and there is a lime kiln in the West Zhuangzi.

Not to mention plant ash.

Although Chen Xian did not major in chemistry at university, his chemistry grades in middle school were not bad, although a lot of knowledge was returned to teachers over the years, but some of the most basic chemical ideas were still retained.

Chen Xian selects a variety of plants and incinerates them to obtain plant ash, and then dissolves and filters them to obtain a carbonate solution.

In order to obtain high-purity potassium carbonate and sodium carbonate, Chen Xian heated and distilled the plant ash solution, and during the distillation process, the crystals precipitated were extracted by filtration, so that the purity of the carbonate obtained was quite high.

After having carbonate, Chen Xian mixed the lime with water, precipitated it, took a clarifying solution, and added carbonate.

Carbonate reacts with calcium hydroxide in lime water to obtain strong alkalis of potassium hydroxide and sodium hydroxide, and calcium carbonate precipitates.

Chen Xian gradually increased the carbonate and weighed the calcium carbonate precipitate to find the optimal reaction ratio of carbonate and lime.

The strong alkali solution obtained by the reaction is boiled and evaporated to obtain potassium hydroxide and sodium hydroxide powder.

After obtaining the strong alkali dry powder, Chen Xian experimented with the saturated solution ratio of potassium hydroxide.

Through the previous test data, Chen Xian adjusted the ratio of lime, carbonate and water, and Chen Xian experimented with the proportion of strong alkali solution that was close to saturation by direct reaction.

After obtaining a strong alkali solution that is close to saturation, it can be directly saponified with oil.

In the information of the Internet writer, there is an optimal ratio of sodium hydroxide and grease reaction, but the strong alkali solution made by Chen Xian from plant ash is a mixed solution of potassium hydroxide and sodium hydroxide, of which potassium hydroxide is the main one, so there must be some slight differences in this ratio.

Fortunately, Chen Xian still remembered that the position of potassium in the periodic table was a little lower than that of sodium, so he used a little increase in the proportion of strong alkali solution to explore the optimal reaction ratio.

After many experiments and observations, he roughly determined the reaction ratio of strong alkali solution and oil.

Through this series of experiments, Chen Xian basically grasped the process data of this local method of producing soap.

At the same time, he also identified the plants with the highest sodium carbonate and potassium salt content in the incineration ash.

Just as he was preparing to design a production line on the basis of this set of data, Peng Yibin, who he had been waiting for, finally came to Dongzhuangzi again.

This time, in addition to bringing fifty elite horsemen, two hundred strong soldiers, and five hundred minions, Peng Yibin also brought more than 1,000 young men and women.

Hearing the news, Chen Xian immediately stopped what he was doing and organized the reception.

Fortunately, Chen Xian had expected and prepared for this matter, and he had already asked people to build three rows of thatched huts along the fence around Xinzhuangzi as a temporary resettlement area.

……

Peng Yibin escorted people to East Zhuangzi, and left 500 minions and more than 1,000 young men and women who were used for trading outside the south gate of Zhuangzi, and lived in Baifu with his relatives.

After settling down, Peng Yibin asked Bai Yuan to send someone to Xinzhuangzi to inform Chen Xian, hoping that he would come up with a trading charter.

That night, the messenger sent by the Bai family to Xin Zhuangzi came back and brought back Chen Xian's message.

Chen Xian asked Peng Yibin to escort people directly to Xinzhuangzi tomorrow, and the two sides traded in Xinzhuangzi.

Peng Yibin listened, and nodded in agreement after a little hesitation.

Early the next morning, Peng Yibin sent his henchmen to accompany him, and took 500 minions to Xinzhuangzi with more than 1,000 men and women.

The personal entourage sent by Peng Yibin is named Peng Hu, who is a slave of the Peng family, and is also a brand leader in the elite cavalry of Peng Yibin's personal guards, that is, Shi Chang, who attacked Xinzhuangzi last time, was injured and captured with Peng Yibin, and was healed by Chen Xian.

Peng Hu is not worried about going to Xinzhuangzi to trade, he has lived in Xinzhuangzi for nearly a month, and he doesn't think there is any Longtan tiger's den.

Peng Hu led people to the new Zhuangzi, the gate of the outer column of the new Zhuangzi was opened, and the gate of the Zhuangzi city was closed inside, and the figures in the defensive towers at the four corners of the Zhuangzi could be vaguely seen.

Chen Xian stood in the square in front of the closed gate of Xin Zhuangzi, and the phalanx that impressed Peng Hu was lined up behind him.

Peng Hu came to the door of the deletion column, and a soldier wearing iron armor and holding an axe and gun standing in the deletion column greeted him and shouted at Peng Hu's team: "Who is in charge, we ask you to come over and speak." ”

Peng Hu commanded a few minions around him, then dismounted and followed the shouting soldiers into the gate of the deletion bar, ignoring the noise of several minions leaders advising him to be careful.

Several minions were a little puzzled and disdainful of Peng Hu's carelessness, and whispered about how to deal with this idiot after being caught for a while.