I am the prince of the Ming Dynasty, I don't give up

Chapter 48 Portland Cement

In the Ming Dynasty, three-in-one soil was used to bond bricks and stones. The book "The Exploitation of the Works of Nature" records: "For tombs and water storage tanks, one part of ash is added to river sand, two parts of loess, and glutinous rice and sheep peach vine juice are mixed evenly, which is called three-in-one soil."

This kind of cement requires glutinous rice, which is very expensive, and directly led to the high cost of civil engineering in ancient China.

Moreover, compared with cement, the quality of this cement is far inferior.

Portland cement is much cheaper than cement mortar, but its effect is better than cement mortar. Cement is not only used to build open-hearth furnaces, but also in the future, as Zhu Houxuan's business expands, the amount of civil engineering in various places will definitely not be small. This kind of cement will be used everywhere, especially in the future, when hydraulic machines are needed, cement will be even more powerful.

Moreover, cement is not just used as a binder, it can also be made into reinforced concrete. Although steel cannot be produced cheaply on a large scale now, the steel bars in it can be replaced by bamboo.

Making Portland cement requires limestone and clay to be burned with a small amount of gypsum as a retarder.

Limestone and clay are both extremely cheap and easy to come by.

Cement production requires two grindings and one calcination. Before calcination, the limestone and clay must be ground into powder and calcined at a high temperature of 1,300 degrees in a vertical kiln. After burning, the obtained cement must be ground into powder again.

Zhu Houxun directly sent Qin Ming to handle the cement burning task.

After receiving the order, Qin Ming went directly to purchase a lime kiln outside the city, and then collected fifty stone mills and more than a hundred donkeys from the surrounding areas. The donkeys were used to pull the mills, which were specifically used to grind materials and produce finished products.

All the lime kiln craftsmen were retained, and then asked to erect kilns in the factory and burn cement. All this was done to ensure that the cement could be used in the palace as soon as possible.

Qin Ming took the paper given to him by Zhu Houxuan, which had the steps for burning cement written on it.

After instructing the craftsmen to grind the materials into powder, they mixed limestone in a ratio of three to one and sent them to the vertical kiln for calcination. The vertical kiln gradually heated up and burned at the highest temperature for three hours before turning off the fire to obtain clinker in the form of large and small stones.

Qin Ming asked the lime workers to pour the clinker onto a stone mill and grind it into powder, and then add some gypsum as a retarder.

Thus the first batch of Portland cement was produced.

After it was brought to the government office for trial, the effect was very poor.

Zhu Houxuan thought about it for a long time and believed that the temperature of the cement kiln did not meet the standard, so he sent Luo Dajiang to improve the vertical kiln design of the cement plant.

Master Luo was an expert in this area. He spent two days modifying the cellar and raising the temperature.

Then the cement was fired again, and the world's first batch of qualified Portland cement was finally born.

The effect of cement was immediate. All the craftsmen who had used cement were full of praise for it, and the main structure of the open furnace was quickly built.

In fact, under the leadership of Zhu Houxuan, the craftsmen of Daye Iron Mine have already mastered a lot of pre-steelmaking technologies.

The iron smelting industry in the Ming Dynasty was extremely developed, with the technology, annual output, and even quality being the best in all dynasties.

Blast furnace ironmaking technology was very common, and the blower was also piston-type, similar in structure to modern blowers.

In this regard, Zhu Houxuan simply allowed Daye Iron Mine to use coke to smelt iron, which reduced fuel costs and increased the stability of fuel sources.

For the blower, only some optimizations have been made to the structure.

As for refractory bricks, high-alumina refractory bricks are directly fired by mixing bauxite and clay provided by Zhu Houxuan. They have low technical thresholds and can easily withstand high temperatures of 1600 degrees.

The most important thing is the gasifier. The fuel of the open hearth furnace is actually natural gas, because the essence of the flame is the burning of natural gas, and the coke is first oxidized and then releases carbon monoxide. Using natural gas directly skips this step, which is more direct.

In addition, the most important thing about the open hearth furnace is that it uses a refractory brick chamber to heat the temperature of the gas and air to over 1000 degrees, increasing the initial energy, and then spraying it into the furnace for combustion, which can successfully make the furnace temperature reach over 1800 degrees.

This open-hearth furnace is designed to produce 10 tons of molten steel at a time. This amount sounds like a lot, but in fact, the volume of such heavy molten steel is only 1.3 cubic meters. A normal open-hearth furnace can produce hundreds of tons of molten steel at a time. It is precisely because this open-hearth furnace was built in the city and is of an experimental nature, so there is no need to make it so large.

With no expense spared in the construction, the open-hearth furnace was quickly built, and then the furnace testing began, mainly to see if there were any problems with the connections between the furnaces.

As a result, a problem was soon discovered.

"Cough cough. Put out the stove quickly, cough cough." Zhu Houxun kept coughing due to the smoke from the coal.

The craftsmen around quickly put out the furnace.

Zhu Houxuan understood what was going on at a glance.

"Why build the chimney so low? Not only is such a low chimney not conducive to smoke exhaust, but the exhaust smoke also falls on our area." Zhu Houxuan looked at Master Luo unhappily.

"Your Highness, this chimney cannot be built that high." Carpenter Luo said in embarrassment, rubbing his hands.

"Why can't it be built higher? With cement, are you afraid that the chimney will collapse if it is built too high?" Zhu Houxun's face turned cold.

When Master Luo saw Zhu Houxuan's expression was not right, he dared not hide it anymore, "If this chimney is built higher, it will be higher than the gate towers of the four gates of the palace."

"If we want to achieve the effect that the prince mentioned, we have to build it higher. It is estimated that the final height will exceed the height of Chengyun Hall," Master Craftsman Luo continued to explain carefully.

Zhu Houxuan was silent. He looked at the city gate tower and Chengyun Hall in the distance and found that it was indeed the case.

Chengyun Hall is the tallest building in the Prince of Jing's Palace and also the tallest building in Qizhou City. It is a symbol of power and status of the Prince of Jing's Palace.

Therefore, Master Luo was very sensitive about the height of the chimney.

Zhu Houxuan showed a hint of irony in his smile. In the past thousands of years, such tall and majestic buildings made people feel awe, but in the next hundred years, the buildings that made people feel awe became such tall chimneys emitting black smoke.
"Master Luo, times are changing!" Zhu Houxuan said softly.

Luo Dajiang didn't quite hear clearly, and after a moment's hesitation he asked, "What did the prince just say?"

"It's nothing. Build the chimney to the height we need. It doesn't matter even if it's higher than Chengyun Hall. If anyone wants to stop you, let him come to me." Zhu Houxuan said lightly.

"Yes, sir!" Master Luo did not continue to argue. The time they had spent together had already given him an idea of ​​the young prince's character.

"Oh right! There's something else you need to do!"

"Your Majesty, please give me your orders!"

"After all, this is an alchemy furnace, so we have to paint something related to alchemy on it, such as patterns of Tai Chi and Bagua," said Zhu Houxun, pointing to the flat furnace under construction.

"Ah?" Luo Dajiang was stunned. This request was really beyond his expectations, but after thinking about it, it was indeed reasonable. "I will ask someone to invite a Taoist priest right away."

"Why invite a Taoist priest? You can just go up and draw one. If you have the meaning, that's enough."

(End of this chapter)