Method for extracting iron from converter steel slag through online reduction

Abstract

The invention provides a method for extracting iron from converter steel slag through online reduction, which comprises the following steps of: (1) after the converter tapping is finished, pouring slag into a slag tank in batches, and adding coke powder into the slag tank after each batch of steel slag is poured into the slag tank; (2) hoisting the slag tank to a tank seat with an electromagnetic device; the liquid iron in the slag ladle is settled by a magnetic field generated by starting the electromagnetic device, so that the slag and the iron in the steel slag are separated; (3) when the liquid iron in the slag ladle is settled through the magnetic field, adding an iron-containing cold charge into the slag ladle, and in the process that the iron-containing cold charge settles under the action of gravity and the magnetic field, enabling molten iron in the steel slag to be attached to the iron-containing cold charge for separation; and (4) the slag ladle is cooled, the cooled slag ladle is inversely buckled on the ground, and slag and iron in the steel slag can be naturally separated. According to the method, the repeated utilization rate of the iron element in the converter slag can be increased, recycling of resources is achieved, generation of solid waste is reduced, and environmental pollution is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of iron and steel metallurgy, and in particular to a method for online reduction of converter slag to extract iron. Background Art

[0002] As a byproduct of steelmaking, converter slag contains a lot of metal oxides, the crystal phase is unstable, and the utilization rate is very low. At present, the utilization rate of converter slag is only 20% to 30%, and the rest can only be piled up as waste, occupying a large amount of land resources and polluting the environment. The iron content of converter slag is 20% to 30%. If it cannot be utilized, it will also cause a waste of resources. At the same time, the huge heat energy of up to 1600℃ during production will not be utilized. Summary of the invention

[0003] In order to improve the resource utilization rate of converter slag and reduce environmental pollution, the present invention provides a method for online reduction and iron extraction of converter slag.

[0004] The technical means adopted by the present invention are as follows:

[0005] A method for online reduction of converter slag to extract iron, specifically comprising:

[0006] (1) After the converter is finished tapping, the slag is poured into the slag pot in batches, and coke powder is added to the slag pot after each batch of slag is poured;

[0007] (2) After the slag in the converter is completely emptied and the coke powder in the slag pot no longer reacts with the slag, the slag pot is hoisted onto a pot stand with an electromagnetic device; the magnetic field generated by the electromagnetic device is activated to cause the liquid iron in the slag pot to settle, thereby separating the slag and iron in the slag;

[0008] (3) while the liquid iron in the slag pot is being settled by the magnetic field, a cold iron material is added into the slag pot. During the process of the cold iron material settling under the action of gravity and the magnetic field, the molten iron in the steel slag adheres to the cold iron material and is separated;

[0009] (4) Cool the slag pot and turn it upside down on the ground. The slag and iron in the steel slag can be separated naturally.

[0010] Furthermore, the amount of coke powder added is 5wt% to 10wt% of the total amount of steel slag.

[0011] Furthermore, after adding coke powder each time, wait until the foam on the surface of the slag pot dissipates before continuing to pour slag into the slag pot.

[0012] Furthermore, the magnetic field acceleration generated by the electromagnetic device is greater than 10m / s 2 , start the electromagnetic device and then shut it down after at least 10 minutes.

[0013] Furthermore, the particle size of the added iron-containing cold material is 20 mm to 50 mm.

[0014] Furthermore, the relationship between the amount of iron-containing cold material added and the weight of the steel slag in the slag pot is: 30kg / t to 60kg / t.

[0015] Furthermore, cooling the slag pot specifically includes: after the electromagnetic device is turned off, the slag pot is suspended to cool in the air for 2 hours to 6 hours; and then the slag pot is cooled by a water bath or water is sprayed on the outer wall of the slag pot for cooling for not less than 24 hours.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The method for online reduction and iron extraction of converter steel slag provided by the present invention can increase the reuse rate of iron elements in converter slag to more than 50%, realize resource recycling and reuse, reduce the generation of solid waste, and reduce environmental pollution; and the phosphorus element in the separated slag is convenient to be extracted by wet leaching, which can be used for the continued recycling of resources; the whole process will not generate secondary pollution.

[0018] Based on the above reasons, the present invention can be widely promoted in the field of iron and steel metallurgy. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The present invention provides a method for online reduction of converter slag for iron extraction, which specifically comprises:

[0021] (1) After the converter is finished tapping, the slag is poured into the slag pot in batches, and coke powder is added to the slag pot after each batch of slag is poured. The coke powder reacts with the acidic oxides in the slag to produce CO gas foaming (C reacts with FeO to produce CO and Fe, and Fe is liquid iron). The thermal energy of the slag can provide the thermodynamic conditions for the reduction reaction;

[0022] (2) After the slag in the converter is completely emptied and the coke powder in the slag pot no longer reacts with the slag, the slag pot is hoisted onto a pot stand with an electromagnetic device; the magnetic field generated by the electromagnetic device is activated to cause the liquid iron in the slag pot to settle, thereby separating the slag and iron in the slag;

[0023] (3) while the liquid iron in the slag pot is being settled by the magnetic field, a cold iron material is added into the slag pot. During the process of the cold iron material settling under the action of gravity and the magnetic field, the molten iron in the steel slag adheres to the cold iron material and is separated;

[0024] (4) Cool the slag pot and turn it upside down on the ground. The slag and iron in the steel slag can be separated naturally.

[0025] By adopting the method for online reduction and iron extraction of converter steel slag of the present invention, phosphorus element is still retained in the slag after separation, which is convenient for wet leaching of phosphorus element in the slag, and can be used for continued recycling of resources. In other methods such as the slag leaching method, phosphorus, calcium and iron are mixed together, and most of the phosphorus element is together with the iron element during the recovery process.

[0026] Furthermore, the iron-containing cold material used is slag steel, granular iron, pig iron block, crushed material, cold-rolled coil, hot-rolled coil or scrap steel.

[0027] Furthermore, the amount of coke powder added is 5wt% to 10wt% of the total amount of steel slag.

[0028] Furthermore, after each addition of coke powder, the slag is poured into the slag pot after the foam on the surface of the slag pot dissipates, and the gravitational potential energy of the steel slag is used to generate kinetic conditions, which can enable the unreacted coke powder to further react with the steel slag.

[0029] Furthermore, the magnetic field acceleration generated by the electromagnetic device is greater than 10m / s 2 , start the electromagnetic device and then shut it down after at least 10 minutes.

[0030] Furthermore, the electromagnetic device includes magnetic poles arranged on the left and right sides of the slag pot. After the electromagnetic device is started, a variable magnetic field can be generated between the magnetic poles on both sides, so that the liquid iron and iron-containing cold material moving downward under the action of gravity in the slag pot cut the magnetic field to generate a vertically downward Lorentz force. The vertically downward Lorentz force can help the liquid iron and iron-containing cold material to sink better, thereby separating the slag and iron in the steel slag.

[0031] Furthermore, the method for generating a variable magnetic field between the magnetic poles on both sides can be: changing the magnitude of the alternating current passed through the magnetic poles on both sides to generate a variable magnetic field, or installing one of the magnetic poles on a track that can be transmitted in a vertical direction, and generating a variable magnetic field by changing the positional relationship of the magnetic poles on both sides.

[0032] Furthermore, the particle size of the added iron-containing cold material is 20 mm to 50 mm.

[0033] Furthermore, the relationship between the amount of iron-containing cold material added and the weight of the steel slag in the slag pot is: 30kg / t to 60kg / t.

[0034] Furthermore, cooling the slag pot specifically includes: after the electromagnetic device is turned off, the slag pot is hoisted to a cooling position and cooled in the air for 2 hours to 6 hours; then the slag pot is cooled in a water bath or water is sprayed on the outer wall of the slag pot for cooling for not less than 24 hours.

[0035] Example 1

[0036] This embodiment takes a 200t converter as an example, adopts the method for online reduction and iron extraction of converter slag of the present invention, the converter slag amount is 10t / furnace, the converter tapping temperature is 1650°C, and the slag temperature at the end of tapping is 1600°C;

[0037] Specifically include:

[0038] (1) Prepare 500kg coke powder;

[0039] After the converter is finished tapping, pour the slag into the slag pot in batches: after the first batch of slag covers the bottom of the pot, add 200kg of coke powder into the slag pot, add 100kg of coke powder into the slag pot after the foam on the surface of the slag pot dissipates, and slowly pour in the remaining slag. If the slag surface floats seriously, stop pouring the slag and add slag pressing materials to press the slag; add the remaining coke powder after the foam on the surface of the slag pot dissipates;

[0040] (2) After the slag in the converter is emptied (the weight of the slag in the slag pot is 10 tons) and the coke powder in the slag pot no longer reacts with the slag, the slag pot is hoisted onto a pot stand with an electromagnetic device; the electromagnetic device is activated to generate an acceleration of 11 m / s 2 The magnetic field causes the liquid iron in the slag pot to settle, thereby separating the slag and iron in the steel slag. The electromagnetic device is turned off after 12 minutes of startup.

[0041] (3) while the liquid iron in the slag pot is being settled by the magnetic field, 500 kg of cold iron-containing material is added into the slag pot;

[0042] (4) Cooling the slag pot: After the electromagnetic device is turned off, the slag pot is lifted to a cooling position and cooled for 6 hours; then the slag pot is cooled in a water bath or water is poured on the outer wall of the slag pot for 26 hours; the cooled slag pot is turned upside down on the ground, and the slag and iron in the steel slag can be naturally separated; the utilization rate of the iron element in the converter slag in this embodiment can reach more than 50%.

[0043] Example 2

[0044] This embodiment takes a 200t converter as an example, adopts the method for online reduction and iron extraction of converter slag of the present invention, the converter slag amount is 12t / furnace, the converter tapping temperature is 1670°C, and the slag temperature at the end of tapping is 1620°C;

[0045] Specifically include:

[0046] (1) Prepare 600kg coke powder;

[0047] After the converter is finished tapping, pour the slag into the slag pot in batches: after the first batch of slag covers the bottom of the pot, add 300kg of coke powder into the slag pot, add 100kg of coke powder into the slag pot after the foam on the surface of the slag pot dissipates, and slowly pour in the remaining slag. If the slag surface floats seriously, stop pouring the slag and add slag pressing materials to press the slag; add the remaining coke powder after the foam on the surface of the slag pot dissipates;

[0048] (2) After the slag in the converter is emptied (the weight of the slag in the slag pot is 12 tons) and the coke powder in the slag pot no longer reacts with the slag, the slag pot is hoisted onto a pot stand with an electromagnetic device; the electromagnetic device is activated to generate an acceleration of 13 m / s 2 The magnetic field causes the liquid iron in the slag pot to settle, thereby separating the slag and iron in the steel slag. The electromagnetic device is turned off after 13 minutes of activation.

[0049] (3) while the liquid iron in the slag pot is being settled by the magnetic field, 400 kg of cold iron-containing material is added into the slag pot;

[0050] (4) Cooling the slag pot: After the electromagnetic device is turned off, the slag pot is lifted to the cooling position and cooled for 5 hours; then the slag pot is cooled in a water bath or by spraying water on the outer wall of the slag pot for 27 hours; the cooled slag pot is turned upside down on the ground, and the slag and iron in the steel slag can be naturally separated;

[0051] (5) Comparing the FeO content in the slag sample before and after treatment, the FeO content before treatment was 23% and the FeO content after treatment was 8%.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for online reduction of converter slag for iron extraction, characterized in that: Specifically include: (1) After the converter is finished tapping, the slag is poured into the slag pot in batches, and coke powder is added to the slag pot after each batch of slag is poured; (2) After the slag in the converter is completely emptied and the coke powder in the slag pot no longer reacts with the slag, the slag pot is hoisted onto a pot stand with an electromagnetic device; the magnetic field generated by the electromagnetic device is activated to cause the liquid iron in the slag pot to settle, thereby separating the slag and iron in the slag; (3) while the liquid iron in the slag pot is being settled by the magnetic field, a cold iron material is added into the slag pot. During the process of the cold iron material settling under the action of gravity and the magnetic field, the molten iron in the steel slag adheres to the cold iron material and is separated; (4) Cool the slag pot and turn it upside down on the ground. The slag and iron in the steel slag can be separated naturally.

2. The method for online reduction of converter slag for iron extraction according to claim 1, characterized in that: The amount of coke powder added is 5wt% to 10wt% of the total slag.

3. The method for online reduction of converter slag for iron extraction according to claim 1, characterized in that: After adding coke powder each time, wait until the foam on the surface of the slag pot dissipates before continuing to pour slag into the slag pot.

4. The method for online reduction of converter slag for iron extraction according to claim 1, characterized in that: The magnetic field acceleration generated by the electromagnetic device is greater than 10m / s 2 , start the electromagnetic device and then shut it down after at least 10 minutes.

5. The method for online reduction of converter slag for iron extraction according to claim 1, characterized in that: The particle size of the added iron-containing cold material is 20mm to 50mm.

6. The method for online reduction of converter slag for iron extraction according to claim 1, characterized in that: The relationship between the amount of iron-containing cold material added and the weight of the steel slag in the slag pot is: 30kg / t~60kg / t.

7. The method for online reduction of converter slag for iron extraction according to claim 1, characterized in that: The cooling of the slag pot specifically includes: after the electromagnetic device is turned off, the slag pot is hoisted to a cooling position and cooled in the air for 2 hours to 6 hours; then the slag pot is cooled in a water bath or water is sprayed on the outer wall of the slag pot for cooling for no less than 24 hours.