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Method for lowering chromium pollution risk in electric furnace slag

A technology for electric furnace steel slag and chromium pollution, applied in the field of metallurgy, can solve problems such as low cooling rate and pollution, and achieve the effects of low energy consumption, treatment cost advantages, and thorough detoxification

Inactive Publication Date: 2019-05-24
WISDRI ENG & RES INC LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] Aiming at the problem of chromium pollution in stainless steel slag, the object of the present invention is to provide a treatment method for inhibiting the dissolution of chromium from stainless steel slag, by adding a modifier to the molten stainless steel slag, and then treating it with a suitable cooling method to achieve a lower cooling rate. The rate is lowered below 1300°C to realize the enrichment of chromium to the stable spinel phase and promote the crystal growth of the spinel phase. Because the spinel phase structure is very stable, it can effectively fix the chromium in the stainless steel slag and obtain chromium-free stainless steel slag

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] After the stainless steel slag produced by the electric furnace is normally discharged, put the molten stainless steel slag into the slag tank. The main components of the stainless steel slag are CaO 46.8%, SiO 2 31.2%, MgO 10%, Al 2 o 3 4%, FeO 3%, Cr 2 o 3 5%.

[0026] Will Al 2 o 3 The modifier is added to the molten stainless steel slag, and the stainless steel slag and Al 2 o 3 Additives are mixed evenly to form molten mixed slag, in which Al 2 o 3 The mass of the additive is 8% of the molten stainless steel slag. Al 2 o 3 Grinding to a particle size of ≤74 mesh.

[0027] Lower the molten stainless steel slag at 3°C / min to below 1300°C to obtain a slag in which chromium mainly occurs in the spinel phase; The leaching concentration is lower than 0.01mg / L.

Embodiment 2

[0029] After the stainless steel slag produced by the electric furnace is normally discharged, put the molten stainless steel slag into the slag pot. The main components of the stainless steel slag are CaO 48%, SiO 2 32%, MgO 8%, Al 2 o 3 4%, FeO 3%, Cr 2 o 3 5%.

[0030] FeC 2 o 4 2H 2 O is added to the molten stainless steel slag, and the stainless steel slag and FeC are mixed by stirring 2 o 4 2H 2 O additives are mixed evenly to form molten mixed slag, wherein the added amount of FeO after conversion is 6% of the molten stainless steel slag. FeC 2 o 4 2H 2 The O additive is ground to a particle size of ≤74 mesh.

[0031] Lower the molten stainless steel slag at 3°C / min to below 1300°C to obtain a slag in which chromium mainly occurs in the spinel phase; The leaching concentration is lower than 0.10mg / L.

Embodiment 3

[0033] After the stainless steel slag produced by the electric furnace is normally discharged, put the molten stainless steel slag into the slag pot. The main components of the stainless steel slag are CaO 48%, SiO 2 32%, MgO 8%, Al 2 o 3 4%, FeO 3%, Cr 2 o 3 5%.

[0034] The MnO powder is added to the molten stainless steel slag, and the stainless steel slag and the MnO additive are mixed evenly by stirring to form a molten mixed slag, wherein the added amount of MnO is 8% of the molten stainless steel slag. MnO is ground to a particle size of ≤74 mesh.

[0035] Lower the molten stainless steel slag at 3°C / min to below 1300°C to obtain a slag in which chromium mainly occurs in the spinel phase; The leaching concentration is lower than 0.12mg / L.

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Abstract

The invention discloses a method for lowering chromium pollution risk in electric furnace slag. The method includes: putting molten stainless steel slag into a slag tank, adding a modifier, and stirring to enable the modifier and the molten stainless steel slag to be mixed well; cooling at a cooling speed of smaller than 20 DEG C / min to below 1300 DEG C to realize chromium-direct-stable spinel phase enrichment; performing hot braising on the slag. The stainless steel slag is thorough in detoxification; after the molten stainless steel slag is well mixed with the modifier, cooling is performed,so that chromium-direction-stable spinel phase enrichment can be realized, and environmental discharging standards can be met completely. The treatment process is low in energy consumption, sensibleheat of the molten stainless steel slag is utilized, and external adding of energy consumption and equipment is not needed, so that the method has great advantage in the aspect of treatment cost. Treated stainless steel slag can be further recycled, and hot-braised stainless steel slag can be safely used in products like cement and roadbed materials.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for reducing the risk of chromium pollution in electric furnace steel slag. Background technique [0002] The iron and steel industry is the basic industry for the development of the national economy and an important material guarantee for the realization of my country's modernization drive. In recent years, my country's stainless steel industry has made great progress and has become a veritable stainless steel production country. As of 2017, my country's stainless steel output reached 2577 tons. Calculated on the basis of approximately 0.25 tons of stainless steel slag produced per ton of steel, the current annual output of stainless steel slag is close to 6 million tons. [0003] During the stainless steel smelting process, due to oxygen decarburization, the chromium in the molten steel will inevitably be oxidized and enter the slag. Chromium is a hea...

Claims

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Application Information

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IPC IPC(8): C04B20/02C04B18/14
CPCY02W30/91
Inventor 操龙虎
Owner WISDRI ENG & RES INC LTD
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