Converter single-slag melting method of high-silicon molten iron

Abstract

The invention relates to a converter single-slag melting method of high-silicon molten iron. The method comprises the following steps of (1) heat balance calculation before oxygen blowing: before theoxygen blowing, according to the molten iron waste steel conditions, target temperature and carbon content control requirements, determining the consumption of lime and caustic calcined dolomite; then, calculating the ore addition total quantity according to the furnace turn test temperature; (2) material addition control: adding the materials into the furnace in three batches; (3) oxygen gun position control performed in four steps. The method provided by the invention achieves the goals of realizing the single slag operation of the high-silicon molten iron, shortening the melting time, achieving the melting balance without spraying and sputtering, reducing the melting time, the metal yield and improving the coal gas recovery and terminal residual manganese.

Description

technical field [0001] The invention relates to the technical field of converter steelmaking, in particular to a control method when the converter uses high-silicon molten iron (Si>0.6%) and adopts single slag smelting. Background technique [0002] The main metal materials for converter smelting are molten iron and steel scrap. The Si content in molten iron is an important heating element in the converter smelting process. The increase of the Si content can increase the heat source of the converter and increase the scrap ratio. At the same time, after the silicon content increases, the amount of molten iron slag increases, which is beneficial to dephosphorization and desulfurization. However, excessive silicon content in molten iron (generally refers to the silicon content of molten iron > 0.6%) brings great unfavorable factors to the operation of the converter, mainly as follows: [0003] 1) Oxidation of silicon produces a large amount of acidic SiO 2 , in order t...

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Problems solved by technology

[0003] 1) Oxidation of silicon produces a large amount of acidic SiO 2 , in order to ensure the alkalinity of the slag, a large amount of lime needs to be consumed;

[0004] 2) The amount of high-silicon slag is large, the loss of metal in the slag increases, and the metal yield decreases;

[0005] 3) The slag flows well during high-silicon smelting and is easy to splash, resulting in increased metal loss, serious environmental pollution, and hidden dangers to equipment and personnel safety;

[0006] 4) Prolong the oxygen blowing time, reduce the utilization rate of oxygen, and make it difficult to pull carbon at the end;

[0007] 5) When high-silicon molten iron is operated with double slag, the smelting time is longer, the amount of gas recovery is reduced, the normal production organization is disrupted, and the continuity and stability of production are affected

[0009] One is to turn over the pig iron block, and then put the pig iron block into the furnace in batches for use; this method divides the whole into parts and uses high-silicon molten iron to reduce the impact of high-silicon molten iron, but disrupts the normal production organization and affects the planned output the completion of

[0010] The second is to carry out pre-desilication treatment of molten iron; however, a special desulfurization device is required to increase the temperature drop of molten iron and the process time

[0011] The third is to mix the high-silicon and low-silicon molten iron through the iron mixing furnace; but it needs a special iron mixing furnace device, and at least the molten iron with low silicon and iron grades can be carried out. At present, the newly built steel mills are equipped with the iron mixing furnace device rare

[0012] Fourth, the converter desiliconizes through double "three stripping" or double slag; when using double "three stripping", special equipment and processes need to be configured to increase metal loss and high cost; when double slag is used for production, it can be effectively Avoid splashing, but it prolongs the smelting time and increases the oxygen consumption. When the slag is released in the early stage, the slag is seriously covered with iron. The iron is seriously oxidized at the moment of oxygen blowing and ignition. 2 o 3 Large smoke and dust, polluting the environment

[0013] To sum up, the disadvantages of high-silicon molten iron for converter smelting outweigh the advantages. The current four treatment methods can only partially solve the disadvantages of high-silicon molten iron for converter smelting, especially the method that needs to increase special equipment, increase substantial production costs