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Processing method for stockpiled EAF stainless steel slag

A technology of stainless steel slag and a treatment method, which is applied in the treatment field of EAF stainless steel slag, and achieves the effects of simple process, cost saving of harmless treatment and easy operation.

Inactive Publication Date: 2015-11-11
NORTH CHINA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Its disadvantage is that the stability of cement and concrete is caused by the volume expansion of chrome slag after cement solidification.

Method used

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  • Processing method for stockpiled EAF stainless steel slag
  • Processing method for stockpiled EAF stainless steel slag

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Embodiment 1: collect the EAF stainless steel slag of stockpiling more than one year, the main chemical composition and content of this stockpile EAF stainless steel slag are: CaO40%, MgO8%, SiO 2 20%, Al 2 o 3 5%, FeO8%, MnO2%, Cr 2 o 3 2%, the above contents are all weight contents. The above-mentioned stockpiled EAF stainless steel slag is placed in a drying oven at 105°C for 6 hours and then cooled to room temperature. The tailings after magnetic separation and extraction of magnetic substances are packed in paper or plastic bags and transported to the refining workshop for use. Mix according to the mass ratio of LF refining slag: stockpiled EAF stainless steel slag = 97:3, put the mixed slag into the LF refining furnace, and form the final refining slag after refining at 1500°C for 50 minutes in a reducing atmosphere. After the LF refining is completed, the final refined slag is transported to the slag treatment workshop through the slag tank, and the post-trea...

Embodiment 2

[0027] Embodiment 2: Collect the EAF stainless steel slag that has been stockpiled for more than one year. The main components and contents of the stockpiled EAF stainless steel slag are: CaO50%, MgO10%, SiO 2 30%, Al 2 o 3 10%, FeO22%, MnO3%, Cr 2 o 3 10%, and the above contents are all weight contents. The above-mentioned stockpiled EAF stainless steel slag was dried in a drying oven at 105°C for 5 hours and then cooled to room temperature. The tailings after magnetic separation and extraction of magnetic substances were packed in paper or plastic bags and transported to the refining workshop for use. Mix according to the mass ratio of LF refining slag: stockpiled EAF stainless steel slag = 95:5, put the mixed slag into the LF refining furnace, and form the final refining slag after refining at 1540°C for 40 minutes in a reducing atmosphere. After the LF refining is completed, the final refined slag is transported to the slag treatment workshop through the slag tank, and...

Embodiment 3

[0028] Embodiment 3: Collect the EAF stainless steel slag that has been stockpiled for more than one year. The main components and contents of the stockpiled EAF stainless steel slag are: CaO45%, MgO9%, SiO 2 26%, Al 2 o 3 7.5%, FeO15%, MnO2.5%, Cr 2 o 3 6%, the above contents are all weight contents. The above stockpiled EAF stainless steel slag is placed in a drying oven at 100°C for 5.5 hours and then cooled to room temperature. The tailings after magnetic separation and extraction of magnetic substances are packed in paper or plastic bags and transported to the refining workshop for use. According to LF Refining slag: stockpiled EAF stainless steel slag = 93:7 mass ratio mixed, put the mixed slag into the LF refining furnace, and form the final refined slag after refining at 1560°C for 35 minutes in a reducing atmosphere. After the LF refining is completed, the final refined slag is transported to the slag treatment workshop through the slag tank, and the post-treatmen...

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Abstract

The invention discloses a processing method for stockpiled EAF stainless steel slag. According to the processing method, the stockpiled EAF stainless steel slag and LF refining slag are mixed; the final refining slag is formed through refining under the reducing atmosphere; and after the final refining slag is post-processed, the processed refining slag can be obtained. According to the processing method for stockpiled EAF stainless steel slag, the high temperature and the reducing atmosphere for LF refining are sufficiently utilized so that Cr6+ in the stockpiled EAF stainless steel slag can be reduced to be Cr3+. According to the method, due to the fact that the characteristic that generation of spinel is facilitated through the high content of Al2O3 in the LF refining slag is fully used and the Cr6+ in the stockpiled EAF stainless steel slag is promoted to be reduced to be Cr3+ through the high temperature and the reducing atmosphere for LF refining, a small amount of Cr2O3 entering the refining slag enters the spinel to be solidified and sealed; and the leaching concentration of the Cr6+ of the processed refining slag is several micrograms per liter and is far lower than the standard limit value in Identification for Leaching Toxicity of Identification Standards for Hazardous Wastes (GB5085.3-2007), and therefore harmless processing of the stockpiled EAF stainless steel slag is achieved. The processing method is simple in technology and easy and convenient to operate, and the harmless processing cost is further reduced.

Description

technical field [0001] The invention relates to a method for processing steel slag, in particular to a method for processing stockpiled EAF stainless steel slag. Background technique [0002] In 2014, China's crude stainless steel output was 21.692 million tons, a year-on-year increase of 14.27%. Assuming that every 3 tons of stainless steel produces 1 ton of chromium-containing waste (mainly including stainless steel slag, stainless steel pickling sludge, etc.), the annual production of chromium-containing waste exceeds 7 million tons. At present, the main production equipment of stainless steel is electric arc furnace (Electric Arc Furnace, EAF) and argon oxygen decarburization furnace (Argon Oxygen Decarburization, AOD), so stainless steel slag mainly includes EAF slag and AOD slag. The main elements of stainless steel slag are Ca, Si, Mg, Al, Fe, etc. However, due to the high content of heavy metals such as Cr in stainless steel slag, its resource utilization must compr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21B3/06
CPCY02W30/50
Inventor 李俊国曾亚南
Owner NORTH CHINA UNIVERSITY OF SCIENCE AND TECHNOLOGY