Li Mengxi couldn't wait to go to the kiln immediately. He asked the craftsmen to come out of a small charcoal kiln as quickly as possible.

Jian Yong only brought back two carts of coal. Maybe Jian Yong thought that two carts was a lot, but Li Mengxi knew very well that just two carts of coal could not make several furnaces of iron, and this amount of coal was only enough for research.

After the craftsmen finished the kiln, Li Mengxi returned to the blacksmith camp. He asked the craftsmen to make some large molds, for example, an oversized iron pot that could stew a cow.

When the craftsman heard Li Mengxi's request, he said it in a responsible manner. The craftsman said that the pot was too big and had to be cast in pieces. It might take a long time and it might not be cast properly in one go.

Li Mengxi smiled calmly, "It doesn't matter, you don't have to cast it in pieces, just make a big mold."

The craftsmen had no choice but to do as they were told.

Half a day later, the coking kiln was built. According to the method of burning charcoal, half a car of coal was put into the kiln and then set on fire.

When the fire in the kiln becomes strong and the temperature in the kiln reaches its extreme, seal the kiln door immediately.

After the charcoal kiln is completely closed, the charcoal fire inside will continue to burn for a period of time, and then will soon be extinguished due to lack of oxygen. At the same time, due to the excellent heat preservation effect of the charcoal kiln, the kiln will be at a high temperature for a long time.

In this way, in the environment of high temperature, high pressure and lack of oxygen, coal changes.

Stuffing charcoal and smothering coke is a technical process. Stuffing charcoal takes a day. As for coal, I have never tried it. I was afraid that opening the kiln too early would affect the coke formation. Li Mengxi waited until the next day and decided to open the kiln until noon the next day.

The craftsman took a hammer and smashed open the kiln door with a bang, and a burst of hot air rushed out.

Li Mengxi looked into the kiln, looking forward to the result.

After the craftsmen dug the kiln completely, someone went in. The person who went in took a basket to pick up charcoal, but found something strange. The charcoal in the kiln was burned into a black lump and turned into stone.

It's not easy to break up.

The craftsman came out to report the situation in the kiln, and Li Mengxi couldn't help but ran in out of curiosity.

In the sweltering kiln room, Li Mengxi saw the black stone in the center of the kiln that had been burned into a solid mass. Seeing this scene, he was sure that the coking was successful.

Looking at his feet, he saw something sticky under his feet. Li Mengxi frowned and moved his feet away. For some reason, there was a black, oily sticky thing in the charcoal kiln.

It shouldn't be, the temperature in the kiln is so high, everything should be burned dry, where does the oil come from?

Li Mengxi was concerned about the condition of the coke and did not pay much attention to the black oil on the ground. He went over and broke off a piece of the coke and looked at it carefully. The coke seemed to be glue that had melted and then solidified together. It was black and shiny, with a uniform structure.

If this thing is right, then iron can be melted into real molten iron.

With molten iron, giant iron objects can be cast and molded in one go.

The craftsmen were asked to move all the coke out of the kiln and weigh it. When the coal was put into the kiln, it was 400 kilograms, and the coke was just over 300 kilograms. That is to say, the coking loss was about 40%.

——

In the blacksmith camp, the mold for a super-large iron pot that can actually stew a cow has been built, and the craftsmen have been waiting for it for a long time.

Li Mengxi came with three hundred kilograms of coke. He handed the coke to the craftsmen and ordered them to open a new kiln, cast iron into it, and smelt it with black coal.

When the craftsmen were carrying away the coke, they all took a second look at the things in the basket that were as black as cow dung cakes.

The smelting process is the same as usual, the kiln is the same, the iron is the same, except that the charcoal is replaced by coke.

Li Mengxi was full of confidence in this smelting. While the craftsmen were busy, he was wondering if there was anything in the coke smelting technology that could improve efficiency.

For example, when using coke, is it better to use large pieces or small pieces?

It seems that small pieces are better. Small pieces are fully exposed to oxygen and the charcoal is easy to burn through. Large pieces of charcoal are not easy to burn through.

I called a craftsman and asked about it, but the craftsman said that big charcoal is better for making iron, but crushed charcoal is not so good.

This puzzled Li Mengxi. He asked the reason, but the craftsman scratched his head and couldn't tell the truth.

Another point that goes against common sense.

The craftsmen have rich smelting experience, and they may be right. However, they may also be wrong. Also, large pieces of charcoal may be better, but the properties of coke may not be consistent, or small pieces may be better.

Li Mengxi realized that it was necessary to conduct a test.

Coke is expensive. Suppose, depending on whether the coke block is large or small, the smelting efficiency of large pieces of charcoal is 1% higher than that of small pieces of charcoal. Improving this process can save 1% of materials.

It is another difficult problem to test the coke smelting efficiency.

Testing coke is different from other tests. In the previous tests, Li Mengxi could think of the difficulties of coke testing only after thinking about it for a moment. The first difficulty lies in the test equipment. Coke is precious and it is impossible to test it kiln by kiln, so small experiments must be done.

Equipment, the second difficulty is how to test the smelting effect.

In other tests, when testing the strength of paper, you can directly test with a knife, and when testing the speed of a waterwheel, you can directly count. These can be directly observed with your eyes. To test the smelting efficiency of coke, you should test the temperature.

But there is no way to accurately measure temperatures over a thousand degrees.

Secondly, there is no method to test high temperature. Furthermore, the difference in smelting temperature between lump coke and powdered coke is likely to be only ten or twenty degrees. This makes it necessary not only to have a method to test high temperature, but also to accurately test high temperature.

Methods.

I think about all the knowledge I have learned, and all I can think of is the methods of measuring water temperature, solution temperature, and low temperature. The school does not teach high temperature measurement methods.

Temperature is difficult to measure, so the next best thing is to use iron to test the smelting effect. Use lump coke to make a furnace of iron, and then use powdered coke to make a furnace of iron. The molten iron smelted by the two smelting methods is cast into iron bars.

Take it to test the quality of the iron bars. If there is a difference in the quality of the iron bars, it means that there must be a better smelting method.

Half a day later, the blacksmiths came over in great surprise and said that the molten iron had melted so quickly that the juice was completely finished.

Li Mengxi wanted to take a look, but the craftsmen were afraid of danger and refused to let him pass.

According to the craftsmen, the molten iron is really molten iron. If you take a spoonful of it, it will flow gurglingly, and it will be as thin as water.

Listening to the descriptions of the craftsmen, Li Mengxi was absolutely sure that liquid pig iron had been successfully smelted.

Finally, the craftsmen scooped up the melted molten iron and poured it into the mold. When hundreds of ladles of molten iron were poured down, the mold was full.

This is the first sight that all the craftsmen have seen. The smelting method used in the past did not melt the iron enough. The molten iron was viscous and had poor fluidity. The molten iron was often blocked halfway and could not be poured in. However, it is so smooth this time, and the molten iron is not as fluid as the water.

It overflowed the same way, this was the first time.

The craftsmen were surprised and started talking about it.

After a period of time, the casting was completed, and the mold was opened to check the sample. A large iron pot with a perfect shape that even four people could not hold in their arms was successfully cast.

Such a large iron pot was cast in one go without any flaws. The craftsmen were very impressed when they touched the flat, shiny and slightly hot iron pot.

——

In the palace of the city lord, Liu Bei and others were summoned by a messenger. The soldier said that the military advisor had forged a heavy weapon and invited him to take a look.

Anything that could be called a valuable weapon by Li Mengxi was absolutely extraordinary.

Liu Bei and others were very curious and hurried to have a look.

When we arrived at the blacksmith camp, we saw from a distance a very big pot propped up on the ground, and a group of people gathered around to look at it.

When he got closer, Liu Bei was both surprised and amused. He knocked twice with his hand, "Such a big pot can cook a cow." Liu Bei said with a smile.
Chapter completed!