On May 25, Li Zhi looked at a dozen crucible craftsmen from Texas and handed over two stones.
In the past, Li Zhi had always asked Cai Huaishui to go to Texas to buy crucibles for burning glass and making steel. In fact, Li Zhi had become the number one customer of the crucible craftsmen in Texas.
This time Li Zhi wanted to build a steelmaking converter, so he simply invited these people at a high price and asked them to come to Fanjiazhuang to build the converter lining for Li Zhi.
With Li Zhitian's large orders for crucibles over the years, these Texans have obviously become rich. At this time, the dozen or so craftsmen were all well-dressed and had rosy faces, and they looked like people living a wealthy life.
The crucible craftsmen looked at the stone Li Zhi handed over, squeezed it, and said, "Master Guo! These are dolomite and kaolinite!"
When Li Zhi heard these old words, he looked at these Texans with admiration and secretly thought that these were indeed craftsmen who had produced countless steel-making crucibles for themselves. In fact, Li Zhi spent a lot of money to find relatively pure dolomite and kaolinite.
We spent a lot of time and hired more than 20 people to look for minerals in Shandong. It took more than two years to find it.
With these two materials, Li Zhi can make a qualified converter lining.
More than a dozen crucible craftsmen passed Li Zhi's two stones to look at, and each one couldn't help but nod in praise. Li Zhi's two stones were of high purity, and were rare good ores, comparable to the ordinary ones that could be found in the mountains.
Ore is very different.
Li Zhi and other technicians looked at the ore before saying, "I want you to use these two ores to make a large blast furnace lining for me."
After listening to Li Zhi's words, a Texas craftsman asked curiously: "We understand that kaolinite is used as a furnace lining. This kaolinite is very tough when heated at high temperatures and is a good material for making crucibles. But why do we use dolomite?"
In fact, what people in the Ming Dynasty called dolomite is calcium magnesium carbonate. Although this ore can also withstand high temperatures, it is rarer and more difficult to process than kaolinite. The reason why Li Zhi chose this material and kaolin
Magnesium oxide is used as the converter lining together with magnesium oxide because it can withstand alkaline molten steel.
Phosphorus is one of the harmful impurities in steel. Steel containing more phosphorus is prone to brittleness when used at room temperature or lower, which is called "cold brittleness". The higher the carbon content in the steel, the greater the brittleness caused by phosphorus.
Serious. Generally, the phosphorus content in ordinary steel is not more than 0.045%, and high-quality steel requires less phosphorus.
However, there are very few iron ores in nature that do not contain phosphorus. Correspondingly, the steel-making material pig iron that Li Zhi can buy on the market in Ming Dynasty must also contain a large amount of phosphorus. These phosphorus elements will form alkalinity when dissolved in molten steel.
Environment. Only by using dolomite to make alkaline furnace lining can phosphorus be removed during the steelmaking process.
In the original history, Bessemer invented the acid converter steelmaking method in 1856. However, acid converter steelmaking cannot dephosphorize. In 1879, Thomas invented the alkaline converter steelmaking method that can handle high-phosphorus molten iron, which allowed European countries to
It can produce ordinary steel on a large scale. Li Zhi used this alkaline converter method.
However, Li Zhi was not prepared to explain these steelmaking knowledge in too much detail to the new craftsmen. Li Zhi said lightly: "My steelmaking blast furnace needs such a lining. You use this dolomite and kaolinite to make a lining that can withstand high temperatures."
The lining is."
The crucible craftsman played with the dolomite for a while, and finally said: "We may also use some black talc in the furnace lining."
Li Zhi nodded and said, "Okay!"
With Li Zhi's permission, the crucible craftsmen went to the carriage to pick up tools and materials, and prepared to build a furnace in a factory provided by Li Zhi and burn the blast furnace lining. Li Zhi stood aside and looked at it, and saw that they were bringing
There were a lot of tools and materials, including five carriages.
"How long does it take to make the inner wall of the converter?"
The leader of the crucible craftsman touched his head and said: "I'm afraid it will take a month!"
Li Zhi nodded and said no more.
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Li Zhi summoned thirty craftsmen who had worked in the crucible steelmaking workshop for many years, and erected a blackboard in the converter steel factory building that had not yet been equipped with equipment to teach the craftsmen new steelmaking knowledge.
These thirty people are Li Zhi's new team for converter steelmaking. Li Zhi intends to let them understand the principles of converter steelmaking, which will help them smelt steel better.
Li Zhi held up a piece of wrought iron and a piece of charcoal and said: "First of all, everyone needs to understand that iron contains carbon. The so-called wrought iron is iron with very low carbon content, while the so-called pig iron is iron with a carbon content of more than 100%.
2% of iron. And if the carbon content is between wrought iron and pig iron, we call it steel.”
The listeners have heard this truth from Li Zhi before, but they just heard it again now.
"So there are naturally two ways to make steel. One is to increase the carbon content of wrought iron. The other is to reduce the carbon content of pig iron. Our converter steelmaking method uses the second method, which is to reduce the carbon content of pig iron.
The carbon content is reduced.”
"We use a blower to blow air from the top into the molten iron. The carbon and impurities in the molten iron react with the air at high temperatures to generate carbon dioxide and other substances. The carbon dioxide will be taken away with the air, while other impurities will
Together with our slagging agent it forms slag.”
"These impurities release a lot of heat when they burn in the air, which will keep the entire molten iron in a boiling state. Therefore, you only need to heat the molten iron once during the entire steelmaking process, and then the molten iron will always be in a high-heat state. At this time
Adding calcium oxide and other slag-forming agents to create slagging can improve the quality of molten steel."
"Everyone knows that the so-called slag making is, in the final analysis, an operation to adjust the impurities in steel and iron. The purpose is to turn the impurities into slag, reduce sulfur and phosphorus below the upper limit of the planned steel type, and reduce the splash and noise during oxygen blowing.
The amount of slag spillage is reduced to a minimum.”
These thirty steel-making workers were all veteran workers in the crucible steel-making workshop. After listening to Li Zhi's words, they all basically understood the principles of converter steel-making. After Li Zhi finished speaking, he looked at the audience's reaction, and the workers
Keep nodding to show that they understand.
Li Zhi looked at his old workers and felt that he would not encounter too many problems in developing converter steelmaking. After all, his crucible steelmaking workshop had been in operation for so many years, and the workers had no idea how to manage the boiling molten iron and how to make slag.
Everyone has their own set of experiences. Li Zhi gives a little bit of advice, and these workers can draw inferences about other cases.
Li Zhi pressed the chalk on the blackboard a little harder and finally said: "Of course, when the molten steel is in a static state, inclusions rise and are removed slowly. Our blower has limited wind power, and the reaction cannot be completed quickly just by blowing from the top of the blower.
We have to use tools to stir the converter. So we need two steam engines for each converter. One is responsible for top blowing and the other is responsible for stirring."r
