Su Ming took his thirteenth brother and Tie Zhu to the salt making station, and saw that there were many more workers working here today than before.

"Brother Chunrui, why are there so many people in the salt factory today?" Su Ming came to the salt pan and saw Cao Chunrui and asked.

"Eighth master! A few days ago, grain was distributed, and all the villages said that if you come back, you will have a way to sell the salt at a high price, so that everyone can eat. So there are a lot more people who take the initiative to come to the salt farm today. Cao Chunrui said.

Working in the salt factory for a month, 80 catties of grain and 200 wen were distributed, which was the rule set by Erweibao before. However, because the imperial court did not pay salaries, Erweibao could only survive with the money from selling salt privately every month, and the money and grain of the salt factory were always owed, so the situation of the salt factory was getting worse and worse.

Now that Su Ming is back, everyone sees hope, and now they are doing more work here, and Su Ren also has money and food to distribute to everyone, so everyone's enthusiasm for work has also become higher.

"This is a good thing, it just so happens that I have some ideas to renovate the salt farm, Brother Chunrui, can you listen to it!

I'm trying to burn something called cement, which becomes as hard as stone when it solidifies when it comes to water......"

Su Ming said his thoughts on the transformation of the salt farm, and Cao Chunrui listened carefully until he finished speaking, and Cao Chunrui thought for a while before speaking.

"If what you said about [cement] is true, it's a terrible thing. The area of our salt factory is a leeward area, and the sun is very abundant, and the wind and sand basically can't blow here.

If you want to experiment, try it in this salt field first! This salt pan is more than four acres in size, and if it is not successful, it will not have much impact on our salt farm. Cao Chunrui said.

"Even if we have to experiment, it won't affect the normal production of Yantian. This salt pan is not small, let's dig a new salt pan here! Su Ming nodded and said.

The new field dug by Su Ming is not the previous way of digging salt pans, bring a canal from the sea, and when the salt pan is full of water and seal the canal, after the salt water in the salt field evaporates, some salt water will be put in to continue to evaporate, until the salt water is salty enough to boil salt.

This time, he planned to draw a canal from the old salt pan and build a new salt pan, which would be larger and shallower, so that it would evaporate faster.

Dig a small salt pan behind this salt pan, and a special pit will be made in this salt pan to take salt water, so that you will not be afraid of staining the salt water and affecting the quality of the green salt.

"Okay, then I will follow your request and let people dig in this area, this piece is about ten acres of salt pans, the depth is only 1 foot, and the canal between the three salt pans is slightly larger. This small salt pan is only half an acre in size, right at the gate of the manor, with a depth of 2 and a half feet, and a reclaiming pit of 6 feet long and 4 feet wide, and a depth of 3 and a half feet. Cao Chunrui listened to what Su Ming said and said to Baosheng.

"Yes, the key to this big salt field is to be flat, ten acres of salt field when the time is deep and shallow, if there is no way to repair the bottom of the salt field is very flat, you can use the bamboo tube I said to measure the balance.

The terrain of the small pool must be lower than that of the large pool, and after digging, the bottom should be tamped, and some water should be sprinkled on the sand every day. I will make the baffle between the three pools with cement separately, and the salt water in the small salt pans will be very clean.

When our other salt pans are renovated in the future, we may bring all the salt water from the salt pans to this small salt pan, and then it will be easier for us to cook salt. Su Ming said.

"Yes, Eighth Master! If the cement you said can really succeed, the salt pan behind the salt pan, the salt drying speed is faster than before, that's not a little, we can build this area into a salt pan at that time, then the salt water every day can't survive? Cao Chunrui said.

"When the cement comes out, we can rebuild the salt factory, and then the mouth of the brine will be directly placed in the yard, and we can even lead all of them to the village to cook the salt pot, which of the several salt fields has the most saltiness, and we can directly use the brine of which salt pan.

At that time, the walls can be built higher, the houses can be built with cement, and our salt factories can be used as defensive places in the event of pirates. The more Su Ming thought about it, the happier he became, as long as the cement came out, it would have a very big effect on the salt farm.

"Then I'll have people dig the salt pan now, it should be dug in five days, and I will ask people to find some stones to pave the salt pan around and at the bottom, and the salt pan will be stronger by then." Cao Chunrui said.

"Yes, after this cement comes, it may still need a lot of coarse sand and stones, Brother Chunrui, you can let people filter some sand and clean it, and if the stones are there, just find that kind of pebbles and smash them with a sledgehammer." Su Ming handed over the work of sand and stones to Cao Chunrui.

Cao Chunrui quickly called the workers over, Su Ming used branches to draw the place to be dug on the ground, and he also said clearly to Cao Chunrui about the design of the canal and baffle mouth linked by the salt field, and now he is just waiting for the cement to burn out.

When the eldest brother Su Ren came back at night, he brought back several soldiers in the fort, he brought back more than 200 catties of gypsum stones, and told Su Ming that he had agreed with the mine owners who sold gypsum in Jinshanwei Town, and he wanted as many gypsum stones as he wanted, and a car only cost 40 yuan, which gypsum ore was not uncommon in Jinshanwei.

By the 25th of March, the two earthen ovens that Su Ming needed had been baked and dried. He commanded on the spot, and had the stones placed in the furnace along the wall of the furnace in a circle, and then added firewood to light the fire, and the fire on the stove rose, and puffs of smoke drifted into the air.

This stove burns quicklime, and the other stove uses the same method to burn plaster.

Quicklime needs to reach a temperature of more than 900 °C in the furnace, and it is still difficult to use this kind of earthen stove.

It is relatively easy to fire the plaster, it takes half a day to burn on a low fire, and a day to burn on a medium fire, and when the fire in the quicklime furnace is extinguished on March 28, Su Ming has already sifted out hundreds of catties of plaster powder with a stone mill.

"Isn't that right?" Su Ren saw that the burned stone that had turned white was taken out of the earthen stove, and hurriedly took it for Su Ming to see.

Su Ming picked up the white stone and threw it the ground, and the stone was shattered.

"There should be nothing wrong with grinding all these white stones into powder, just like gypsum, let's try it." Su Ming saw that the quicklime was successfully fired and said to the eldest brother.

In the past few days, Erweibao has raised stone mills from where, and thousands of catties of refractory powder have been grinded. When the four brothers returned home, Su Zhe looked at Su Ming with a bag of quicklime.

"Put the gypsum powder in the crucible and stir quickly, and when the temperature of the gypsum powder feels higher than the temperature of the boiling water, mix it with refractory powder and white stone powder to cool it down quickly, and the ratio of refractory powder: white stone powder: gypsum powder is 15:4:1......" Su Ming tried his best to always be able to listen to everyone and command everyone, and soon something that looked like cement appeared in front of him.

"It should be possible now, it stands to reason that this cement should be stored for more than 20 days and the best effect is used, let's try it first." Su Ming said as he took some cement, mixed it with sand and stones, mixed it with water, stirred it into a slightly thinner shape, and waited.

The four brothers were waiting here, Su Ming couldn't help but smile when he saw this, everyone paid great attention to it after hearing about the role of cement, and the eldest brother didn't even allow the people in the castle to talk about collecting tiles, bricks, and porcelain pieces for grinding.

"It will take at least a day for this cement to solidify, so we can't wait like this. Fifth brother, you let people continue to burn stones and gypsum according to the method I said, the amount of refractory powder is still not enough, if we want to build more salt pans for the salt field, this refractory powder may cost more than 5,000 catties. Su Ming said.

Every few hours Su Ming saw that the cement slab was dry, so he poured some water on it, and until the afternoon of the next day, Su Ming saw that the cement slab was already a little dry, so he picked up a stone and smashed it down on the cement slab.

The middle of the cement slab was cracked, and Su Ming couldn't help frowning. He had never really fired cement in his previous life, he only knew the principle of making cement, and he was afraid that it would not work to use cement of such strength.

"Fifth brother, how is it?" Su Ren entered the courtyard and saw Su Ming frowning and asked.

"The strength is not enough, it may be that the cooling rate is too slow, or the solidification time is too short." Su Ming said.

"What then?" Su Ren was also very anxious when he heard this.

"There is no problem with the material and ratio, tonight we will go to the crucible at night, fry it and spread it directly in the yard to cool down, and the day after the experiment at night can be dried for two days, let's take a look!" Su Ming said.

The material, principle, and ratio are all known, but it is not so easy to make cement. Su Ming took the newly cooled cement and re-watered it to solidify, and when the solidification time was almost enough, he went to the experiment again. Although the strength of the cement slab is far from what I imagined, it is much better than the first time.

Su Ming smashed the cement slab with a stone, although it could be smashed, but it was very laborious, and if it was left for a month, the effect was estimated to be much better.

And he made salt pans, not how strong the walls needed to be, as long as they didn't leak.

Two days later, the results of the experiment on the effect of the newly made cement showed that Su Ming's soil cement was fully able to meet the needs of Erweibao and make a new salt pan.

And Su Ming also plans to try more, strive to make harder cement, and then rebuild the walls of Erweibao and increase the height, if the pirates come again, they will be safer.

In the early morning of March 30, Su Ming, Su Ren and more than a dozen others came to the salt factory with more than 300 catties of cement, and two salt pans had been dug here, waiting for Su Ming's cement.

Su Ming first let the two salt pans and the middle canal sprinkle a layer of dry cement, so that it would be easier for the cement and the stone sand at the bottom to solidify after a while. Then Su Ren divided the labor, and soon everyone in the two new salt pans began to get busy.

Su Ming kept staring at the construction site, and he asked that the height of the bottom of the salt pan should definitely be set, and the cement around the salt pan did not need to be too thick, more than an inch was already about the same. They don't have a lot of cement, and this time they can only meet the transformation of this one salt pan first.