After knowing the basic principles, the smelting of metal is actually not mysterious.

For example, if you want to smel the red copper ore mainly composed of copper oxide, you only need to add carbon to replace the oxygen in the copper oxide. Of course, in the reverse process, it takes a very high temperature to replace oxygen atoms from the stable molecular structure.

High temperature is the second element in metal smelting besides carbon.

The principle is simple and there is nothing mysterious, but the high temperature has stumped countless scientists and engineers from ancient times to the present. Even on the earth that is considered to be scientifically developed, how to achieve sufficient high temperature is still a huge problem.

Of course, the ancients were entangled with how to make the temperature reach the level of metal melting, while modern people were entangled with how to generate the sun-like high temperature, how to increase the core temperature, how to increase the duration of the high temperature, and how to make the high temperature controllable...

...Around temperature, countless worldly problems have plagued mankind and hindered the pace of human progress.

What bothered Chen Zheng's progress was also extremely simple to modern people, but extremely difficult for Chen Zheng, who was a alien star - how to use charcoal to reach a high temperature of more than 1,000 degrees.

The melting temperature of copper element is as high as more than 1300 degrees, while the melting temperature of iron element is as high as more than 1500 degrees.

Compared with the elemental substance, the melting temperature of copper alloy is much lower. For example, bronze is only 900 to 1,000 degrees. Although the melting point of bronze is different depending on the formula, it is generally lower than 1,000 degrees Celsius.

If you remember correctly, the melting temperature of copper oxide should be around 1200 degrees, which is much higher than that of ordinary bronze.

The combustion temperature of ordinary coal is about 900 degrees, and the combustion temperature of high-quality lignite in civil boilers is only 1,000 degrees. With the help of blowers, the combustion temperature of anthracite in steel mills can reach 1,700 to 1,900 degrees, while blast furnaces using coke can reach a high temperature of 2,300 degrees.

It can be seen that even in modern times with advanced technology, it is difficult for ordinary civilian temperature to exceed 1,000 degrees, and this is still the case when coal is used as fuel.

As for the combustion temperature of charcoal, it is even lower, only 700 degrees. With the "advanced" mud furnace and blowing equipment (bellows), the combustion temperature of charcoal can barely reach 1,000 degrees.

There were few records of the use of "carbonite (coal)" in ancient times in the Central Plains, and even smelting metals, charcoal was used more often.

The smelting temperature of bronze is very low, and it can reach 1,000 degrees to dissolve under the conditions of using charcoal. But iron is different. Even the cast iron that is commonly used (mainly iron, carbon, and silicon), its melting point must exceed 1,200 degrees.

Although this temperature is only 200 degrees, this more than 200 degrees is a distinction between the Iron Age and the heavenly chasm of the same era. It took thousands of years for human civilization to cross this bottleneck of 200 degrees.

By comparing the above information, it is not difficult to find out why ancient times experienced the "Bronze Age" first, and then the "Iron Age".

The difficulty of using mere charcoal to smelify copper oxide with a melting point of 1,200 degrees is self-evident. However, for Chen Zheng, he was different from the ancients who felt the stones across the river. Since he had the wisdom of his predecessors, all he had to do was bend over and pick it up.

Compared with the simple and crude carbonization pool, what Chen Zheng has to do next is not only an important step that human civilization has taken - smelting blast furnace.

To be precise, it is actually a small blast furnace similar to the period of the civil steelmaking process. Of course, since there is no high-quality anthracite, Chen Zheng still needs to make some structural adjustments if it is replaced by charcoal.

The most important part of these adjustments can be said to account for more than 50% of the entire project volume, namely the blowing equipment and the heat recovery system.

That's right, in order to use charcoal to answer higher temperatures, Chen Zheng needed a more complex system.

The first thing to do is design work.

Spread out a piece of air-dried tree bark, Chen Zheng used a thin strip of charcoal to write and draw on the uneven paper.

The blower system is naturally a blower, to put it bluntly, it is a large human bellows. As for the bellows themselves, it is not difficult, but how to provide power and achieve a sufficiently large air supply is the biggest problem.

Fortunately, Chen Zheng did not need to smel the copper ore. Even if he carried a few boxes back, a blower system several times that of an ordinary bellows could be done. As for the driving power, it is naturally not a problem to push and pull back and forth by the human arm. Chen Zheng built a transmission system similar to an old-fashioned train, which can convert the downward force into circular motion. The simple belt system drives the entire bellows to cycle back and forth.

The heat recovery system is high-end, but it is actually even simpler to say it. It is nothing more than mixing the hot waste gas with the fresh air coming in the bellows and then sending it back to the furnace.

On the one hand, the inlet air temperature is increased, which is conducive to increasing the furnace core temperature. On the other hand, the oxygen in the exhaust gas and incompletely burned carbon monoxide can also be re-entered into the furnace for secondary reaction, greatly improving the reaction efficiency.

However, how to design this exhaust gas recovery system, how to solve the airtightness, and how to use the power of the bellows to fully mix the exhaust gas and air... These are the biggest design difficulties in the entire project.

After conquering these difficulties one by one, Chen Zheng could obtain a part of copper with a not very purity. As for how to remove impurities from these copper products... that is another even bigger problem.

After more than an hour of typing on the bark paper, Chen Zheng finally stopped writing with satisfaction. The imaginary difficulties were solved by Chen Zheng one by one during this period. When he put down the slender carbon strip, he felt quite contented.

Indeed, using some small changes in the project to achieve the problem that has troubled him for a long time, and that feeling was indeed very good. But soon, Chen Zheng's pride in his heart turned into bitterness.

After planning for a long time, he found that there was one of the most important parts that he forgot to calculate, that is...weather!

In such a cold weather, how should he make mud bricks? How to slip away the gaps?

Even if the ground is baked and snow water is melted and mud is added, how should we air-dry it after it is beaten into mud bricks? It will be frozen and cracked before the mud embryo is dried!

Similarly, even if everything goes well, Chen Zheng built a small blast furnace, how to solve the sealing problem!? Use the kneaded mud to slip away the gap? Before the mud is dry, the wall will be frozen and cracked!!

“…It seems that there is still a lot to do…”

Chen Zheng shook his head helplessly.

It is really much simplified compared to what you actually need to do.

But, there will always be ways to overcome these difficulties, but the plan needs to be adjusted slightly.

Before building a small blast furnace, Chen Zheng also needed to build a drying room.

"It needs to be expanded..."
Chapter completed!