Traveling through ancient times: Savages are hungry for food

The first time iron was smelted, all three furnaces failed.

After a whole day and night, all the charcoal in the furnace had burned out.

However, the hematite in the furnace did not undergo any significant chemical changes.

Sang Tian, ​​with his hair scratched into a mess by his hands, kept inspecting and testing the furnace.

What exactly is the problem?

The tribesmen also knew that the iron smelting had failed.

Although they were looking forward to it, Sang Tian had already told them that there would be countless failures in the iron smelting process.

They also gently comforted Sang, asking her to relax and take it slow.

Finally, Sang Tian finally figured out which step was wrong.

The main problem is insufficient temperature.

Hematite is reduced to iron by charcoal only at high temperatures.

When the temperature is insufficient, the decomposition and reduction reactions of hematite proceed very slowly or almost do not occur.

Most hematite remains in its original ore state and may still be bright red or dark red in color.

The situation now is exactly the same as it was in the furnace.

There are almost no major changes.

The reason for the insufficient temperature is that there is hematite between the charcoal, and the speed of the bellows is not fast enough.

This prevents the charcoal fire from spreading quickly.

This is why the temperature in the furnace is not high.

Oh my, Sang Tian licked his upper lips.

I know what's wrong with you, and I'm going to cure you now!

Second Ironmaking! Begin!

The tribesmen quickly cleaned out the contents of the three furnaces.

Only then did Sang Tian take a closer look at the impurities and the furnace that had been cleared out.

There is a lot of unburned charcoal left at the bottom of the furnace!

This is because the heat generated by combustion is limited and the surface of the charcoal may only be partially burnt black.

And it is not completely converted into gases such as carbon dioxide or carbon monoxide to participate in the reduction reaction.

There is basically no molten iron produced in the furnace, and it is mainly a mixture of raw hematite and incompletely burned charcoal.

But it’s not without gain!

At the bottom of the furnace, a very small amount of iron is still reduced.

Although it is dispersed in the ore in the form of tiny particles, it is difficult to aggregate into iron that can be collected.

But at least it shows that there is nothing wrong with the steps.

Sang Tian regained his confidence.

Reinstall it with a layer of charcoal and a layer of hematite.

……

We learned from the failure of the first iron smelting attempt.

During the second iron smelting, the tribesmen put all their strength into pulling the bellows continuously.

Sang Tian kept observing the situation inside the furnace!

Sang Tian almost laughed out the evil voice of Gulala, the God of Darkness!

Because! The hematite in the furnace reacts very violently!

Less than ten hours later!

Molten iron was successfully extracted in the furnace!

This made Sang Tian very happy!

Inner thoughts: "As expected of me! I knew I was a genius beauty!

It was a success on my second attempt at iron smelting! Amazing!

Who in the world can be my enemy?

Hahahaha, ah hahahahahahaha..."

So much so that Sang Tian didn't think too much about why he succeeded in smelting iron even though the time was not enough this time.

Even though I felt that there was something wrong with the molten iron, and it was different from what was described in the book,

However, a few hours later.

Sang Tian couldn't laugh anymore.

Damn it!

How dare you play tricks on me! Damn it!

After the liquid in the furnace was released and cooled, Sang Tianfa found that it was unusually brittle.

After some careful research, I found that the temperature was too high.

In the furnace, hematite is rapidly reduced.

A large amount of carbon will react with iron to form carburization, which will increase the hardness of the resulting iron but reduce its toughness, forming a product similar to pig iron.

Moreover, due to the high degree of carbonization, it becomes very brittle and difficult to carry out subsequent processing.

Moreover, if the bellows is struck too quickly, it is very likely that the charcoal will burn extremely quickly under high temperature, and a large amount of it will be consumed in a short period of time.

This results in a lack of sufficient reducing agent in the later stage of the reaction to continue the reduction reaction.

Fortunately, no damage was caused to the furnace.

Excessively high temperatures may cause the inner wall of the furnace to melt or peel off, affecting the service life of the furnace, and may even cause the furnace to rupture, causing molten iron and ore to leak.

This is not worth the trouble.

……

The third iron smelting.

failure

Summarizing experience, it takes too long!

The iron is oxidized.

Under long-term high temperature environment, the iron that has been reduced has very little oxygen content in the furnace.

Oxidation occurs and the yield of re-iron decreases.

The fourth iron smelting.

failure.

Summarizing experience, there is too much slag.

As time goes by, impurities in the ore will continue to react with slag-forming agents (such as limestone) to form slag.

Too much slag will wrap the molten iron, making it more difficult to separate the molten iron from the slag.

At the same time, it will also take away some iron, causing iron loss.

The fifth iron smelting.

failure

Summarizing experience, the gas composition in the furnace changes too much.

Burning a large amount of charcoal will produce excessive carbon monoxide and carbon dioxide and other gases, which will affect the gas pressure and atmosphere in the furnace.

It is not conducive to the stable progress of the reduction reaction.

The sixth iron smelting.

failure.

Summarizing the experience, the purity is insufficient.

Excessive burning of charcoal will produce ash and other impurities that will mix into the molten iron and reduce the purity of the iron.

The seventh iron smelting attempt failed...

The eighth iron smelting attempt failed...

The ninth attempt at iron smelting failed...

The first iron smelting failed...