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

An argon-oxygen refining and low-carbon chromium technology, which is applied in the field of refining high-carbon ferrochrome alloys into low-carbon ferrochrome alloys, can solve problems such as difficulty in reducing carbon, increasing difficulty in reducing chromium oxide, and increasing refining costs

Inactive Publication Date: 2011-09-21
CHANGCHUN UNIV OF TECH
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  • Abstract
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  • Claims
  • Application Information

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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 am

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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] In the experiment, a top-bottom double-blown converter with a production capacity of 5 tons was used as the refining furnace. The top lance 1 was composed of 3 water-cooled nozzles arranged in a triangle; Auxiliary furnace body 2 with a height of 1.5 meters can be removed; an exhaust channel that can move up and down is installed above the auxiliary furnace body 2. Pa (Pa) exhaust fan.

[0059] 4 tons of carbon content (wt.%) is 8.2%, chromium content (wt.%) is 70% primary smelt to transfer in the converter, measure its temperature to be 1575 ℃, add 35 kilograms of light calcined calcium oxide powder and Add 1.5 kg of iron oxide and 1.5 kg of manganese oxide, then top and bottom blowing argon (nitrogen) / oxygen to start pre-oxidation of the melt.

[0060] Start the top-blowing argon (nitrogen) / oxygen, first set the top-blowing flow rate to 8.0 cubic meters per minute, the top-blowing argon (nitrogen) / oxygen mixing ratio to 6:4, and set the height between the nozzle of t...

Embodiment 2

[0070] Still using the above-mentioned 5 tons of top and bottom double-blown converters, 4 tons of carbon content (wt.%) is 7.9%, chromium content (wt.%) is 68% of the primary smelt into the converter, and its temperature is measured as 1570°C, after adding 20 kg of lightly burned calcium oxide powder, start blowing argon (nitrogen) / oxygen at the top and bottom again, set the flow rate of top blowing to 6.0 cubic meters per minute, and the mixing ratio of top blowing argon (nitrogen) / oxygen to 5: 5. The height of the nozzle of the top lance from the still liquid level of the melt is set to 0.25 meters, the flow rate of the bottom blowing is set to 1.8 cubic meters per minute, and the mixing ratio of the bottom blowing argon (nitrogen) / oxygen is 3:7.

[0071] After 20 minutes, the melt temperature was measured to be 1680°C, the top blowing flow rate was adjusted to 9.5 cubic meters per minute, the top blowing argon (nitrogen) / oxygen mixing ratio was adjusted to 3:7, and the heig...

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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 production operation 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...

Claims

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Application Information

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IPC IPC(8): C21C7/068
Inventor 吴化王淮尤文张德江
Owner CHANGCHUN UNIV OF TECH
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