Chapter 61

In the history of ironmaking, coke, iron ore and limestone are the three main raw materials for ironmaking. The west, which started the history of modern ironmaking, believed that coke, like steam engine, iron and steel, was one of the four main factors contributing to the accelerated development of technology in the first industrial revolution.

The position of coke in the history of iron smelting is unshakable.

In later generations, modern iron smelting was marked by the construction of large blast furnace. However, the realization of mechanized coking and steam blowing technology is the prerequisite for iron smelting with large blast furnace.

Although Shi Xiong knows how to make coke and what a blower is, he can't make mechanized coking and steam blower under his current conditions.

Therefore, the stone bear can only use the most primitive indigenous coking and wooden bellows as blowing equipment.

All these things were learned by the ancestors of China thousands of years ago when they worked in the museum.

Although the history of iron smelting in China is earlier than that in the west, the modern iron smelting originated in the west, and the mechanized coking also originated in the UK.

In Britain in the 17th century, the rapid development of capitalist economy greatly stimulated the demand for iron and steel, but a huge obstacle plagued the development of iron and steel in Britain, that is, the shortage of iron smelting fuel.

At that time, whether in China or in other countries, it was a common understanding in the East and the west to use charcoal as fuel to smelt iron.

However, the long-term iron smelting with charcoal led to the felling of a large number of trees and the destruction of vegetation. To develop the iron smelting industry, the heat and temperature generated by charcoal combustion were not enough. Therefore, in the 17th century, an urgent problem was the development of new fuels.

At that time, some people used coal instead of charcoal, but the sulfur contained in the coal would cause the hot brittleness of pig iron, making it impossible to forge. Later, someone replaced charcoal with coke, and finally achieved success, but the success took more than 80 years.

The man who solved the coke problem for England was Abraham Darby.

Mr. Darby was born in 1678. In his early years, he was an apprentice in a maltose factory in Birmingham. In 1699, after his apprenticeship, he moved to Bristol, where he started a company with others to make household copper pots. Later, because of the high cost of copper, Darby decided to try to cast the pot with iron, which was successful and applied for a patent.

The cast iron pots used in the gaoshu tribe are probably produced by Mr. Darby's company

Cast iron pots have brought Mr. Darby huge profits, but similarly, to produce a large number of cast iron pots, we need a lot of pig iron.

So Darby set up his own iron works and carried out the experiment of making iron with coke.

In the experiment, Darby found that coke is not as easy to burn as charcoal, so it is necessary to improve the blast facilities and adjust the structure of the furnace to obtain more sufficient wind power, so that coke can be fully burned. Therefore, he improved the inner diameter of the blast furnace to adapt to coke ironmaking, and installed a new set of blast facilities for the blast furnace. The improved blast furnace successfully produced pig iron with coke in 1709.

The coke ironmaking is successful, but the hydraulic blast of water turbine is used. This kind of wind is only suitable for small blast furnace. For large blast furnace, the wind generated by hydraulic blast is too small.

This problem was not solved until 1776, when steam engine replaced hydraulic blast in blast furnace ironmaking. So far, the ironmaking industry not only got rid of the dependence on wood, but also got rid of the dependence on water, so as to obtain sufficient development space. However, ironmaking at this time is not enough to be called the realization of modern ironmaking. It will take 1904 for this process to come.

In other words, now, including Britain, the most developed country in the world, smelting iron only uses local blast furnace. That is to say, it is equivalent to the kind of local blast furnace used in steel making after the founding of the people's Republic of China.

No matter what blast furnace is used to smelt iron, coke is indispensable.

If you want to coking, in this case, you can only use local coke oven to coking.

Although the big pit excavated by the stone bear's clan can also be used for coking, it is not a local coke oven, but it is enough for coking and firing firebricks.

Shi Xiong plans to build a new local coke oven after the coal in this pit is turned into coke and enough refractory bricks are fired.

The local coke oven, also known as the local kiln, was invented by the Chinese people. The earth kiln can't be built by digging a big pit casually. To build a fully coking earth kiln, it needs a lot of processes.

For example, it's very good to put 10000 Jin of coal into this big pit which has just been dug out, and can refine 3000 Jin of qualified coke. If it wasn't for firing refractory bricks at the same time, stone bear wouldn't have adopted such backward coking technology.

Shixiong had seen many coking earth kilns built in the early 20th century in Northeast China. Although these coking earth kilns look very backward, the actual coking efficiency is still good.

Almost all of these coking kilns are open-air kilns. In this kind of kilns, a pit with a depth of more than one meter and a diameter of seven or eight meters is dug out on the ground by hand. The height of the pit can be more than two and a half meters when the depth of the pit and the height of the masonry are added up.

Flue is the key procedure of building kiln, and two layers of flue should be built.

The first layer of flue is built with lump coal in the center of the kiln, and coal is loaded around the flue, which is pulverized coal. When the coal is loaded to a certain height, the coal shall be stepped flat and solid, and then the second layer of flue shall be built.

The second flue is much more complex than the first. This layer of flue also has a center. Around the center, stone is used to build 16 or 18 flat flues with a width of 60-70 cm and a height of 20 cm. Each flue is connected with the center. Then add coal for the second time, cover all the flues with pulverized coal, up to half a meter thick.

At this time, the ignition is started, and the easily combustible wood chips are ignited and put into the center flue to fall into the bottom flue, and the coal block and pulverized coal are burned. When burning to the center flue of the second floor, put in wood chips to support combustion. Then there was the third coal addition, which was still fine coal with a thickness of about 70-80 cm.

When burning, the central flue will collapse, and the flame will spit out from the small flue to the outside. The more it burns, the more prosperous it will be, and the outside will come out from the center.

When the fire came, the coking man surrounded the kiln with stones or fragments of bricks and tiles. When the flame comes out of the brick and there is blue smoke in the flame, it is a sign of coking. At this time, it is necessary to plug the hole immediately and then cover it with sand.

After the sand is covered, spray water to cool down, and then take it out after cooling. The coking process is completed.

It takes more than 30 people to refine coke in one kiln. If you can practice two kilns a day, you can produce about 50 tons of coke in one kiln!

Therefore, the coking efficiency of this kind of local kiln is very good.

In the future, Shi Xiong planned to use this kind of earth kiln for coking. But now, he needs to first turn the coal in that big pit into coke, and at the same time, he needs to burn the refractory bricks.