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Synergistic treatment method of stockpiled eaf stainless steel slag and lf refining slag

A stainless steel slag and collaborative processing technology, which is applied in the field of steel slag processing, can solve the problems of the number of times of hot refining slag recycling and processing rate constraints, and achieve the goal of improving the processing effect, reducing processing energy consumption, and saving processing costs Effect

Inactive Publication Date: 2017-08-25
NORTH CHINA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Hot state recycling is mainly to return hot refining slag to the electric furnace or converter process to replace lime desulfurization and dephosphorization to reduce lime consumption in the steelmaking process, and at the same time effectively recycle the heat of the residue to reduce energy consumption and Pollution to the environment; however, due to the enrichment of sulfur and phosphorus in the slag, the number of recycling of hot refining slag is restricted
Cold treatment is to mix cold refining slag with iron-containing materials, binders and other materials, and then return to blast furnace ironmaking or converter steelmaking after cold pressing; but this method can only use the flux of refining slag, and the treatment rate is limited. restrict

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Embodiment 1: collect the EAF stainless steel slag that stockpiles more than one year, the main chemical composition and content of this stockpile EAF stainless steel slag are: CaO 40%, MgO 8%, SiO 2 20%, Al 2 o 3 5%, FeO 8%, MnO 2%, Cr 2 o 3 2%, and the above-mentioned contents are weight proportions. Collect cold LF refining slag, the main chemical composition and content of the LF refining slag are: CaO 30%, MgO 7%, SiO 2 6%, Al 2 o 310%, FeO 0.3%, Fe 0.3%, the above contents are weight ratio. Stored EAF stainless steel slag, LF refining slag and coke powder were placed in a drying oven at 100°C for 6 hours and then cooled to room temperature. After mixing the materials evenly, put them into a ceramic crucible, then put the ceramic crucible into a microwave oven, keep warm with slag wool around the crucible, heat it for 90 minutes under 150W microwave power, turn off the microwave oven, open the furnace door, take out the material and cool it to room temper...

Embodiment 2

[0028] Embodiment 2: collect the EAF stainless steel slag that stockpiles more than one year, the main chemical composition and content of this stockpile EAF stainless steel slag are: CaO 50%, MgO 10%, SiO 2 30%, Al 2 o 3 10%, FeO 22%, MnO 3%, Cr 2 o 3 10%, and the above-mentioned contents are weight proportions. Collect cold LF refining slag, the main chemical composition and content of the LF refining slag are: CaO 70%, MgO 16%, SiO 2 30%, Al 2 o 3 45%, FeO 2.5%, Fe 2.5%, the above contents are weight ratio. Stored EAF stainless steel slag, LF refining slag and coal powder were placed in a drying oven at 105°C for 5.5 hours and then cooled to room temperature. Mass ratio, after mixing the materials evenly, put them into a ceramic crucible, then put the ceramic crucible into a microwave oven, keep warm with slag wool around the crucible, heat it under 300W microwave power for 70min, turn off the microwave oven, open the furnace door, take out the material and cool...

Embodiment 3

[0029] Embodiment 3: collect the EAF stainless steel slag that stockpiles more than one year, the main chemical composition and content of this stockpile EAF stainless steel slag are: CaO 45%, MgO 9%, SiO 2 25%, Al 2 o 3 7.5%, FeO 15%, MnO 2.5%, Cr 2 o 3 6%, and the above-mentioned contents are weight proportions. Collect cold LF refining slag, the main chemical composition and content of the LF refining slag are: CaO 50%, MgO 12%, SiO 2 18%, Al 2 o 3 23%, FeO 1.4%, Fe 1.4%, the above contents are weight ratio. Stored EAF stainless steel slag, LF refining slag and coke powder were placed in a drying oven at 110°C for 4.5 hours and then cooled to room temperature. Mass ratio, after mixing the materials evenly, put them into a ceramic crucible, then put the ceramic crucible into a microwave oven, keep warm with slag wool around the crucible, heat it under 450W microwave power for 50min, turn off the microwave oven, open the furnace door, take out the material and coo...

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Abstract

The invention discloses a synergistic processing method of stacked EAF stainless steel slag and LF refining slag. The method comprises the following steps: uniformly mixing the stacked EAF stainless steel slag, the LF refining slag and coke powder and / or pulverized coal to form mixed slag, and then heating, cooling and post-processing the mixed slag to obtain the processed refined slag. Under the high temperature effect, carbon in the coke powder or pulverized coal is used for reducing Cr<6+> in the EAF stainless steel slag to Cr<3+>; by sufficiently utilizing the characteristic that the high content of Al2O3 in the LF refining slag facilitates the generation of spinel, the reduced Cr2O3 enters the spinel to be cured and sealed, the leaching concentration of Cr<6+> in the refining slag is several micrograms per liter and is far less than a standard limit value of the national standard dangerous waste identification standard leaching toxicity identification (GB5085.3-2007), the harmless treatment of the stacked EAF stainless steel slag is effectively realized, and the harmless treatment of the EAF stainless steel slag and synergistic treatment on the cold-state LF refining slag can be realized; the process is simple, the waste is treated by virtue of waste, and the harmless treatment cost is saved; the method has characteristics of energy conservation, environmental protection and good treatment effect.

Description

technical field [0001] The invention relates to a processing method for steel slag, in particular to a cooperative processing method for stockpiling EAF stainless steel slag and LF refining 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, i...

Claims

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Application Information

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