The reason for the poor slag splashing effect of steelmaking converter

Your amount of scum is a bit small, but according to your description, since the scum is inactive after a minute, how can you still pour the slag? This is a problem, if your description is not problematic, it means that there is a problem with your slag sputter gun or furnace type. It can be analyzed in this way, the kinetic energy of nitrogen when you splash slag is certain, and under normal circumstances, it should be able to splash good slag, but it is not good in the near future, and there can only be two reasons.

First, the gun position is inaccurate, and it is higher than before. Second, the bottom of the furnace is deep. In fact, if your gun position has not changed, there is only one reason why the bottom of the furnace is eaten or the molten pool is too large, and if the molten pool is large, it will cause the liquid level to drop, resulting in a very poor slag splashing effect.

By the way, there is another point, since you pour the slag can't melt through, why splash the slag well? Is there such a situation, the slag is thicker when the furnace is poured, but it becomes muddy and foamy when the steel is tapped? If there is such a situation, it is basically that the molten pool is too large.

The problem of the bottom of the furnace is actually related to the molten pool, the molten pool is very easy to eat the bottom of the furnace, if you make the molten pool small by the method of mending the furnace or hanging slag, the bottom of the furnace will naturally not eat, in the past we need to melt the bottom of the furnace here, because the molten pool is small, the final slag alkalinity is high, and the final slag is too thick at the bottom of the furnace. Now because the slag is too small, the final slag is always muddy, and there is also such a situation, if necessary, it is necessary to make up the size of the surface and make the molten pool smaller, so that the bottom of the furnace will not be eaten, and the slag splashing effect will also be significantly improved.

According to my experience, compared with the converter furnace protection situation of our factory, the amount of dolomite added in your factory is too small, and it is estimated that the MGO content of converter final slag is too low, so it is recommended to add 100 150kg light burning when filling blowing, and about 100kg can be appropriately added when the tapping temperature is high and the slag is splashed. It's not easy for you to end up with a slag thin, whether it is a low carbon at the end point due to the variety structure requirements or other reasons. Only by finding the cause at the source can the furnace protection problem be solved.

The highest furnace age of 120t converter in our factory is 25784 furnaces.

Summary. The advantage is that slag retention is good for the maintenance of the converter and is not harmful. The final slag of the converter is a slag with a certain alkalinity and contains a certain amount of magnesium, and the slag will be blown in this furnace to make the slag have a certain alkalinity and magnesium oxide, which can reduce the erosion of the furnace lining, and another biggest advantage is that a layer of viscous slag can be hung on the large surface, so as to protect the large surface.

The advantage is that slag retention is good for the maintenance of the converter and is not harmful. The final slag of the converter is a certain alkalinity, and contains a certain amount of magnesium slag precursor, after the slag will be blown in this furnace to make the slag have a certain alkalinity and guess the magnesium oxide, which can reduce the erosion of the furnace lining, and another biggest advantage is that Huiyin can hang a layer of viscous slag on the large surface, so as to protect the large surface.

All in all, the advantage is that it can improve the metal yield, make the initial slag early, and the disadvantage is that it will increase the rise of the slag cavity.

How to judge the temperature based on the flame when making steel.

The basis for judging is the brightness and hardness of the flame, and if the illusion is excluded, the brighter the flame, the higher the temperature, and vice versa.

Generally, according to the composition of molten iron and the requirements of smelting steel, the method of forming a group and fighting slag is determined. At present, there are three types of slag making methods commonly used in domestic plants: single slag method, double slag method and double slag retention method. (1) The single slag method and the single slag method operation is that the slag is only made once in the smelting process, and the slag is not poured halfway until the end of the mill.

When the silicon, phosphorus and sulfur content in molten iron is lower than that of the collapse finger, and the steel grade does not have high requirements for phosphorus and sulfur, the single slag method can be used. The single slag method has a simple process, short smelting time and good working conditions. The dephosphorization efficiency of the single slag method is about 90%, and the desulfurization efficiency is 30% and 40%.

2) Double slag method The operation method of pouring out part (1 2 1 3) slag in the middle of blowing, and then adding slag material to make new slag is called double slag method. When the silicon content of molten iron (> is high and the phosphorus content (> is high, the double slag method is used to make a low alkalinity of the initial slag first, and at the end of silicon oxidation, most of the phosphorus enters the slag and then pours out part of the initial slag, and the slag is re-made, so as to improve the total dephosphorization efficiency and reduce the consumption of lime, which is conducive to the later production of high alkalinity slag and reduce the erosion of the furnace lining. When refining medium and high carbon steel, it is difficult to remove phosphorus to the required limit when the carbon is reduced to the required level of tapping by the single slag method, and the double slag method must be used.

Of course, the slag dumping operation takes up time. The removal rate of the double slag method can reach 92% to 95%, and the desulfurization rate is about 60%. (3) The slag retention method in which part or all of the final slag of the upper furnace is left in the furnace for the next furnace to be used by the slag retention method, which is called the slag retention method.

The final slag of the double slag method generally has a high alkalinity and a certain Fe0 content, and the temperature is high, and it has a certain ability to remove phosphorus and sulfur to the molten iron, and it also contains a large amount of physical heat. Therefore, it is of great practical value for blowing high and medium phosphorus molten iron. However, because the upper slag contains a large amount of Fe0, the slag retention method is easy to cause splashing when mixing with molten iron, so it must be operated with caution.

The desulfurization rate of the slag retention method is also high, up to 60% to 70%.

In the early stage of blowing, the main characteristics of the reaction in the furnace are the rapid oxidation of silicon in the molten iron, the rapid increase of acid oxide (SiO2) in the slag, and the temperature of the melt pool is still low. However, at this time, a large amount of lime should be added to form a slag with alkalinity not lower than that as soon as possible, so as to shorten the transition time of the acid slag, so as to reduce the loss of the furnace lining and increase the amount of phosphorus removal in the early stage. Therefore, a higher gun position should be used in the early stage of blowing to stabilize the iron oxide (FeO) in the slag at about 25%, and quickly form Cao Feo SiO2 with a melting point of only 1205 on the surface of the added lime to accelerate the melting and dissolution of lime.

If the gun position is too low, it will cause insufficient (FeO) in the slag and generate 2CaO2 with a melting point of up to 2130 on the surface of the lime block, which will hinder the melting of the lime. However, the gun position should not be too high, so as not to cause the concentration of (FeO) in the slag to be too large, and the slag will be seriously foamed and splashed.

The best position should be to properly froth the slag in the furnace, i.e. the emulsion rises to the vicinity of the furnace mouth without ejecting.

In actual production, the production conditions are ever-changing, and the gun position cannot be static, but should be adjusted accordingly according to the specific situation. It is mainly used to adjust the gun position in terms of the depth of the molten pool, the temperature and composition of the molten iron, the quality and dosage of lime, and the oxygen supply pressure.

Some of the reasons for running slag are because you leave too much slag, and some are because the slag is not good in the early stage, which leads to sudden and violent oxidation after dissolving. Generally speaking, the control gun position is at a low place, stand up, and if you can't stand it, add some white ash or magnesite to press it, and let it run a little bit, and it will be good for a while. If you run hard, you can only lift the gun, pour some scum, and continue to blow.

Running scum is like a human fever, you have to let it out this energy, all you can do is make it a little smaller.

In the early stage of blowing, the slag is used to see if the scrap steel added is slag waste.

When blowing, add all the lime to the light burn, plus half of the total amount.

Then prepare 200kg of lime to thicken the slag.

Look at the fire to see if the slag has melted or not.

Add 200kg on one side and lower the gun position a little.

Increase the depth of its impact.

It is best to control the oxygen supply pressure within a fixed range.

Try not to move during the blowing process, and in the later stage, the outlet pressure can be adjusted to facilitate the pulling of c.