How steel is made
This enlightenment book must be familiar to everyone, and he tells us with vivid examples how the iron will is forged on the road of revolution. This book is of great benefit to the shaping of children's character and personality.
I bought this book for my child during the summer vacation, and I plan to let her study it well. When I first got the book, the child asked me a crying question: "I don't want to go to the factory to make steel, what is this for?" ”。 this... I didn't know how to answer for a moment. Later, after careful consideration, he said to the child passionately: "Is steel hard?" Is steel useful? Do you want to have a will of steel? Do you want steel to be as indestructible as steel? Do you want to be a pillar of steel? If your answer is yes, read this book carefully! Then, with his eyes shining, the child went into the study with the book in his arms.
Presumably, many people will have similar problems when they first see this book when they are young. It is estimated that parents will have similar statements, so in this article, the profound connotation and educational significance I will not explore, today I will talk about the literal meaning of the sentence "how steel is made".
How did steel come about?
Turn stones into iron
Iron is smelted from iron ore
The basic chemical principle is a simple chemical equation
3CO + Fe2O3 == 2Fe + 3CO2
There are many kinds of iron ore: hematite [the main component is iron oxide (Fe2O3)], pyrite [the main component is ferrous sulfide (FeS2)], rhombite [the main component is ferrous carbonate (FeCO3)], magnetite [the main component is ferric oxide (Fe3O4)] and so on.
The chemical equation above is the smelting principle of hematite. At high temperatures, reducing carbon monoxide is reacted with iron oxide, which can generate elemental iron and carbon dioxide.
So where does carbon monoxide come from? When I was a child, there was no heating in the house, and when it was cold, I used a coal stove to heat it, and there was a long iron pipe on the coal stove that led to the window, which discharged the exhaust gas after the coal combustion to the outdoors. Under normal circumstances, the fire is burned during the day to cook and warm, the stove is open, and a large amount of oxygen is fully reacted with coal, and the exhaust gas produced at this time is carbon dioxide. At night, or when the family is out, the stove lid will be covered, at this time the amount of oxygen is reduced, the coal is not burned sufficiently, and a large amount of carbon monoxide will be generated. At that time, there were often incidents of gas poisoning.
The same is true of the carbon monoxide needed for ironmaking.
General ironmaking, the more common method is blast furnace ironmaking. The so-called blast furnace is the following look:
Ore, limestone coke is poured from the top of the furnace, the lower part of the furnace is drummed into hot air (above 1300 ° C), a redox reaction occurs with the material in the furnace body, the coke is oxidized to carbon monoxide, carbon monoxide will reduce the iron from the iron ore, flowing out from the bottom of the furnace in the form of molten iron, and the impurities in the limestone and iron ore react to form the slag floating on top of the molten iron and clearing out from the slag outlet.
Everyone pays attention to the three paths in the schematic diagram, purple is the process of producing reducing agent carbon monoxide, orange is the process of reducing iron ore from molten iron, and gray is the process of removing impurities.
At this time, iron is called "pig iron", which still contains more impurities (carbon content is greater than 2%, and there are many other impurities), which is brittle and easy to break, and it is still far from "steel".
Hundreds of steel
If pig iron is to be smelted into steel, it is also necessary to improve the impurity composition, and different impurities increase and decrease. The main one is to further reduce the carbon content to less than 2%.
Steelmaking, with the help of three types of equipment, converters, open hearths and electric furnaces
The working method of the converter is relatively simple, let's briefly introduce it.
At the beginning of steelmaking, 1200 ~ 1300 °C of liquid pig iron and a certain amount of scrap and quicklime are injected into the converter, and then the air is inflated and the converter is rotated to make it stand upright. In this process, the surface of liquid pig iron will react violently, so that silicon and manganese elements oxidize to form slag, and the reaction is fully carried out by convection. After a period of time, when there is only a small amount of silicon and manganese left in the molten steel, the carbon element begins to oxidize, generating carbon monoxide and releasing a large amount of heat, making the molten steel boil violently, and the carbon monoxide that overflows the furnace mouth will burn to produce a huge flame. Finally, phosphorus also undergoes oxidation reactions and further forms ferrous phosphate. Ferrous phosphate reacts with quicklime to form calcium phosphate and calcium sulfide to form slag. When the phosphorus and sulfur elements gradually decrease, the flame subsides, and brown iron tetroxide vapor appears at the mouth of the furnace, the steel has been smelted. Finally, the converter is turned to a horizontal position, the molten steel is poured into the molten steel ladle, and the deoxidizer is added for deoxygenation.
After experiencing a thousand hammers and hundreds of tempers in the blast furnace, and turning a thousand times in the converter, a good furnace of steel is really made.
How can people not be like this, the tempering of tribulations makes people firm, people's feelings make people retreat properly, good steel is not only strong, but also more resilient; people's hearts must be both internal and external.