Method and improved device for argonoxygen refining of low-carbon ferrochrome

Abstract

The invention provides a method and an improved device for argonoxygen refining of low-carbon ferrochrome. In the method, high-carbon ferrochrome melt is subjected to argonoxygen refining under conditions of large oxygen volume blowing and a higher temperature, the high high-carbon ferrochrome melt is subjected to a violent and uniform oxidization reaction performed under large oxygen volume throughout an oxidization period by utilizing and controlling a splashing process in the oxidization period of the refining, and thus, the carbon reducing process of the melt is accelerated and the loss of chrome is reduced. To prevent serious splashing out of a furnace, a refining converter is improved. When the method and the device are used, low-carbon ferrochrome in which the carbon content (weight percentage) is lower than 0.15 percent can be obtained, and the loss (weight percentage) of the chrome is less than 5 percent. The control method adopted by the invention is favorable for productionoperation and realization of one-line automatic control.

Description

technical field [0001] The invention relates to a method for reducing carbon in high-carbon and high-chromium alloys, in particular to a method for refining high-carbon ferrochrome alloys into low-carbon ferrochrome alloys. Background technique [0002] Low-carbon ferrochrome alloy is an important raw material for smelting special steel and ultra-low-carbon alloy structural steel. The lower its carbon content and the higher its chromium content, the higher its economic value and use value. [0003] At present, the methods for smelting low-carbon ferrochrome alloys are mainly three-step method and "Perrin method". Carbon ferrochrome alloy is used as raw material to produce silicon chromium alloy, and then silicon chromium alloy is used as raw material to produce low carbon ferrochrome alloy, thereby obtaining low carbon ferrochrome alloy with carbon content (wt.%) lower than 0.5%. The disadvantage of this kind of method is that the process is long, the power consumption is h...

AI Technical Summary

Problems solved by technology

In order to reduce the oxidation loss of chromium, a large amount of aluminum, ferrosilicon, chrome ore, etc. are usually added to reduce the chromium oxide in the slag in the later stage of refining, but because the chromium content in the ferrochromium alloy melt is high and the chromium oxide content in the slag is also high , the addition of aluminum and ferrosilicon can only partially reduce the chromium oxide in the slag, and a large amount of aluminum and ferrosilicon will be consumed to increase the refining cost

Adding chrome ore can properly supplement the chromium in the ferrochrome alloy melt, but it cannot reduce the content of chromium oxide in the slag, and at the same time, it will increase the content of harmful impurities such as carbon, sulfur and phosphorus in the ferrochrome alloy melt

In addition, before adding a large amount of aluminum and ferrosilicon, it is necessary to add a large amount of slagging materials such as calcium oxide and auxiliary slag-forming materials during the oxidation period of argon-oxygen refining to increase the alkalinity of the slag and prepare for the later addition of ferrosilicon to reduce chromium oxide , but adding a large amount of calcium oxide and other slag materials will form a thicker and more viscous slag layer on the surface of the melt, which hinders the discharge of oxidizing gases in the melt. For example, a thicker and more viscous slag layer on the surface will greatly affect the oxidation reaction of carbon and cause a large amount of oxidation of chromium

Moreover, increasing the amount of slag will also reduce the concentration of chromium oxide in the slag, making it more difficult to reduce chromium oxide.

[0011] 2) Due to the high carbon content in the high-carbon ferrochrome alloy melt, a large amount of oxygen blowing is required for decarburization, and a long blowing time is required, and a large amount of oxygen blowing and long-time blowing will not only reduce production efficiency, but also easily cause a large amount of chromium oxidation loss

[0014] 5) A large amount of top and bottom re-blowing of oxygen will cause a violent oxidation reaction with carbon, which will increase the temperature of the melt and generate a large amount of reaction gas, which can easily cause the gas in the ferrochromium alloy melt and slag with high viscosity Boiling occurs when the content increases, resulting in splashing hazards. Generally, efforts should be made to avoid the occurrence of splashing

Reducing the amount of top and bottom blowing oxygen can avoid and reduce its splashing, but it will make it difficult for top blowing oxygen to rush into the viscous slag and ferrochrome melt, making it difficult to reduce carbon

[0015] In addition, the furnace mouth of the current converter and AOD furnace is small and short. When the ferrochrome alloy melt and slag boil and splash, it is easy to cause a large amount of ferrochrome alloy melt and slag to overflow and splash out of the furnace mouth, causing danger and loss

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