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Recovery method of chromium in high chromium-content slag in steel making-LF (ladle furnace) working procedure
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A recovery method, -LF technology, applied in the direction of improving process efficiency, etc., can solve the problems of chromium slag polluting the environment and so on
Active Publication Date: 2014-11-26
CHENGDE JIANLONG SPECIAL STEEL
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[0008] The object of the present invention is to propose a method for recovering chromium in high chromium slag in the steelmaking-LF process, to solve the problem of chromium slag polluting the environment
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specific Embodiment 1
[0024] A method for recovering chromium in high chromium slag in the steelmaking LF process, comprising the following steps:
[0025] (1) Make a mixture of dry high-chromium slag and carbon powder, and the ratio of high-chromium slag and carbon powder is 10:1. This step is to mix the raw materials to ensure the reduction effect;
[0026] (2) During the period from converter steelmaking tapping to ladle arriving at LF station, add the dry mixture into the ladle;
[0027] (3) Blow inert gas into the molten steel in the ladle to stir and heat it in LF. In the high-temperature reducing atmosphere, reduce the hexavalent chromium in the heavy chromium slag to metallic chromium in molten steel;
[0028] As a preference, the inert gas is argon;
[0029] In particular, the reducing atmosphere is that the oxygen potential of the molten steel in the ladle is as low as Cr 6+ Conditions that can be reduced, the oxygen content in the steel finally reaches 10ppm;
specific Embodiment 2
[0030] (1) Make a mixture of dry high-chromium slag and carbon powder, wherein the ratio of high-chromium slag and carbon powder is 15:1. This step is to mix the raw materials to ensure the quality of the reduction;
[0031] (2) During the period from converter steelmaking tapping to ladle arriving at LF station, add the dry mixture into the ladle;
[0032] (3) Blow inert gas into the molten steel in the ladle to stir and heat it in LF. In the high-temperature reducing atmosphere, reduce the hexavalent chromium in the heavy chromium slag to metallic chromium in molten steel;
[0033] As a preference, the inert gas is argon;
[0034] In particular, the reducing atmosphere is that the oxygen potential of the molten steel in the ladle is as low as Cr 6+ Reducible conditions, the oxygen content in the steel finally reaches 7ppm;
specific Embodiment 3
[0035] (1) Make a mixture of dry high-chromium slag and carbon powder, wherein the ratio of high-chromium slag and carbon powder is 20:1. This step is to mix the raw materials to ensure the quality of the reduction;
[0036] (2) During the period from converter steelmaking tapping to ladle arriving at LF station, add the dry mixture into the ladle;
[0037] (3) Blow inert gas into the molten steel in the ladle to stir and heat it in LF. In the high-temperature reducing atmosphere, reduce the hexavalent chromium in the heavy chromium slag to metallic chromium in molten steel;
[0038] As a preference, the inert gas is argon;
[0039] In particular, the reducing atmosphere is that the oxygen potential of the molten steel in the ladle is as low as Cr 6+ The conditions that can be reduced, the oxygen content in the steel finally reaches 5ppm.
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Abstract
The invention discloses a recovery method of chromium in high chromium-content slag in a steel making-LF (ladle furnace) working procedure. The recovery method comprises the following steps: (1) mixing dried high chromium-content slag and carbon powder to form a mixture, and enabling a ratio of the high chromium-content slag and the carbon powder to be 10:1-20:1; (2) adding the dried mixture in a steel ladle in a period from converter steelmaking and tapping to steel ladle arriving in an LF station; and (3) blowing inert gases in liquid steel in the steel ladle, stirring and heating in an LF, and reducing hexavalent chromium in the high chromium-content slag to be chromium metal in liquid steel in a high temperature reducing atmosphere. The recovery method has the advantages that the dried high chromium-content slag and the carbon powder form the mixture, then the mixture is put in the steel ladle in the period from converter steelmaking and tapping to steel ladle arriving in the LF station, argon is blew in the steel ladle, and an inside of the steel ladle is in the reducing atmosphere, thereby prompting the hexavalent chromium in the high chromium-content slag to have a chemical reaction, the hexavalent chromium is reduced to be the chromium metal to blend in the liquid steel, and high-carbon chrome-containing steel is formed.
Description
technical field [0001] The invention relates to a method for reducing high-valent chromium, in particular to a method for recovering chromium in high-chromium slag in the steelmaking-LF process. Background technique [0002] In 1973, the World Health Organization (WHO) announced 14 kinds of essential trace elements for human body, and chromium (Cr) is one of them. Trivalent chromium in a low-oxygen state is an essential trace element for the human body and has important nutritional functions, while hexavalent chromium is a highly toxic teratogenic and mutagenic agent, and the toxicity of hexavalent chromium is 100 times that of trivalent chromium. It is one of the 129 key pollutants recognized by the US EPA. The maximum allowable value of chromium in the air is 0.lmg / m 3 The World Health Organization stipulates that the limit value of hexavalent chromium in drinking water is 0.05mg / l. For wastewater discharged into rivers or lakes, the limit value of trivalent chromium is ...
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