In half a month, everything was ready.

A small blast furnace has been built, and a lot of coke and iron ore has been prepared. After everything is ready, under the leadership of Zhu Youxiao, more than a dozen iron smelting workers found from private steel plants immediately started the furnace and smelting iron.

As iron ore, limestone and other materials were poured into the mouth of the material, coking coal started to burn in the furnace.

"It's out, it's out."

As the first furnace of molten iron flowed out of the discharge port, the expressions on everyone's faces became excited, but not long after, Zhu Youxiao couldn't be happy.

The molten iron came out, but from the thick consistency, an experienced worker immediately concluded that the molten iron was not of high quality. To put it bluntly, the sulfur content did not meet the standard.

I took the pig iron out to test it, and it was indeed too crisp.

"Increase the amount of slag and enable the heat storage room." Zhu Youxiao commanded on the spot. If you want to desulfurize during the blast furnace iron smelting process, theoretically, as long as there is more slag, the more thorough the desulfurization will be. At the same time, the higher the temperature, the more sulfur it will be discharged with the gas.

Under the command of Zhu Youxiao, the second furnace began to smelter again.

A worker waved his whip and drove the horse to pull the blower. The gas injection in the heat storage chamber was already burning red, and the hot air was constantly blowing into the furnace, increasing the temperature in the furnace. At the same time, the intake of slag such as limestone also increased.

Soon another furnace of iron flowed out, but the situation was still very bad, and the sulfur content of the iron refined was still too high.

This result made Zhu Youxiao a little crazy. It shouldn’t be! Why is this happening?

For Zhu Youxiao, steel smelting was limited to its theoretical advantages and was in a blank stage in practice. He did not understand what the problem was on the spot.

"Your Majesty, have you used too much slag, which makes you use too much coke?" Xu Guangqi guessed. Zhu Youxiao suddenly realized and instantly understood the problem.

If the slag is used, the coke ratio will naturally increase, and more coke will be used. The main source of sulfur in molten iron is coke. Although the sulfur content in iron ore is high, it is still relatively low compared to coke.

Theoretically, the more slag the furnace, it does reduce the sulfur content in the molten iron. However, the more things are, the amount of coke is increased, which is a completely opposite result.

"It seems that low-sulfur coal must be used." Zhu Youxiao sighed. Where can I find low-sulfur coal in the first half of the time? By the way, isn't the Xingtai area very famous in steel smelting in later generations? There is probably going to be there.

"Xu Aiqing, it seems you have to do this." Zhu Youxiao put away his disappointment and said to Xu Guangqi.

"Please give me the order." Xu Guangqi didn't understand, but his admiration for Zhu Youxiao was still very high. Zhu Youxiao said: "Take a few prospecting masters and go to the Cizhou area to explore it. There should be high-quality iron ore and low-sulfur coal there. I will teach you how to detect it later."

"I obey the order." Xu Guangqi was still very happy to take on this task. If there were good mines and good coal, then there would be good iron and good steel.

"If you can find it, it will be a great achievement." Zhu Youxiao made a verbal promise in order to increase Xu Guangqi's enthusiasm.

"I dare not take credit for the sake of the court." Xu Guangqi said quickly. This may not be found! You can't speak too much.

Zhu Youxiao smiled and then demonstrated the sulfur-containing detection method of coal to Xu Guangqi on the spot. Xu Guangqi has made great progress in chemistry recently and has mastered the basic test methods.

After some testing, Zhu Youxiao found that the coking coal he used this time had a sulfur content of as high as 2%, which was simply impossible to see directly. No wonder the iron he practiced was not qualified.

Although the iron produced was not qualified, the pig iron produced by the blast furnace for one day was produced, which amazed the iron smelting masters.

The quality of the iron produced is higher than that of the pig iron of private steel mills in northern China. It is not up to standard for producing military equipment, but it is still possible to produce agricultural tools and other things. Previously, on the battlefield, the sword held by the generals were cut off by someone. It was obvious that the craftsmen made of steel made of inferior pig iron from the north, which was very brittle.

"Your Majesty, we can try it with charcoal, it should be able to produce good iron." One of the iron smelting masters suggested to Zhu Youxiao. Zhu Youxiao was stunned after listening to this suggestion, yes! It's not necessary to use coking coal to make iron.

Since the sulfur content of coking coal is too high, try it with charcoal. The blast furnace was made of charcoal from the beginning. Although the temperature is not as high as that of coking coal, the sulfur content is reduced! Moreover, there is a heat storage room that blows hot air, so you can try it.

"Okay, then try it with charcoal." Zhu Youxiao took this suggestion and immediately asked the workers to change the charcoal. After changing the charcoal, a furnace of molten iron was still smoothly refined, but the speed was slower. After all, the temperature was not as high as coke, so the efficiency naturally decreased.

However, the quality of the iron released is excellent, and the sulfur content immediately decreases.

This is a very surprising result. These pig irons are of high quality and can be used to make military equipment after they are turned into steel by using the stir-frying method.

However, the blast furnace of the Royal Military Factory was tested and produced for a few days, and the process was not very smooth. Either something was wrong here or something was wrong there. Zhu Youxiao’s problem of not being professional enough was exposed. Fortunately, it was just a small problem. After working together with the iron smelting masters to solve the problem, they were all solved one after another.

In terms of efficiency, the production of only 15 tons per day is reduced, which is 5 tons less than coke. However, this is also very terrifying, and the iron produced is completely sufficient for military use.

A small blast furnace of only fifty cubic meters is already extremely despicable in this era.

With a daily output of 20 tons, 7,300 tons of pig iron is produced every year, 15 tons per day, and 5,400 tons per year. Just one blast furnace is enough for the steel needed by the army.

On average, each soldier consumes 20 kilograms of steel, 5,400 tons of pig iron is enough to supply the steel consumption of 500,000 soldiers.

The blast furnace of the Royal Military Factory has great advantages in pig iron production efficiency, but the transportation cost is a drag. Iron ore and charcoal are all costly to transport. However, despite this, compared with pig iron in the south, there is still a great advantage in cost, at least one third lower than the pig iron production cost in the south.

Zhu Youxiao did not intend to use the Royal Military Factory as a test furnace for production, but planned to build another blast furnace near the iron ore.

The site selection of the steel production base is also planned. In later generations, Handan and Xingtai areas, Handan is one of the four major iron-rich ore-rich in China. Zhu Youxiao remembers this clearly. Xingtai areas seem to have low-sulfur coal, but the memory is very vague. Even if the low-sulfur coal cannot be found, the iron-rich ore in Handan is enough to make people excited. The high content of iron-rich ore and few impurities can not only reduce costs, but also smelting steel with higher quality.
Chapter completed!