Sectional type smelting equipment for low-lean iron ore and operation method of sectional type smelting equipment

Abstract

The invention relates to sectional type smelting equipment for low-lean iron ore and an operation method of the sectional type smelting equipment. The sectional type smelting equipment comprises a hydrogen shaft furnace; the melting separation furnace is arranged below the hydrogen shaft furnace; the pellet inlet is formed in the lower portion of the hydrogen shaft furnace, inserted into the side wall of the melt separation furnace and communicated with the melt separation furnace. The retaining wall is arranged in the melt separation furnace, the first-section melt separation furnace is arranged on the side, close to the hydrogen shaft furnace, of the retaining wall, and the second-section melt separation furnace is arranged on the side, away from the hydrogen shaft furnace, of the retaining wall; the gas supply assembly is arranged on the side wall and the bottom wall of the melt separation furnace; the heating piece is arranged on the top wall of the first-section melting separation furnace; the mechanical stirrer is arranged in the second-section melting separation furnace; the slag modifier bin is arranged above the second-section melting separation furnace; an iron outlet is formed in the side wall of the first-section melting separation furnace; and the slag outlet is formed in the side wall of the second-section melting separation furnace. According to the method, the pre-reduced pellets are subjected to final reduction in the first-section smelting separation furnace, the slag and the molten iron are obtained, the slag exceeding the retaining wall flows into the second-section smelting separation furnace, and the slag in the low-lean iron ore is fully utilized through slag adjustment.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a segmented smelting device for low-lean iron ore and an operating method thereof. Background Art

[0002] With the gradual depletion of high-quality mineral resources that are easy to select and smelt iron and easy to select and extract aluminum, the external dependence and prices of iron ore and bauxite continue to rise, which poses a major hidden danger to the development of my country's national economy. As the world's largest iron ore consumer, China has long been in a passive position in the bargaining power of iron ore imports, which has greatly affected the healthy development of the domestic steel industry. Therefore, comprehensive utilization of mineral resources and innovation of metallurgical processes are particularly important. Improving the utilization rate of mineral resources through scientific and technological innovation, especially for low-grade lean ores and polymetallic co-existing ores, can significantly increase the overall value of resources and reduce dependence on high-grade ore resources.

[0003] In the current existing technology, two technical means are generally used for the application of low-poor iron ore. The first is to rely on the ore dressing process to screen the low-poor iron ore, improve the grade of iron ore by flotation or magnetic separation, and use the low-poor iron ore for ironmaking by grinding, reduction, roasting and other processes. However, such technical means will cause some low-poor iron ore to be wasted in the screening process because it does not meet the screening conditions, and the low-poor iron ore cannot be fully utilized; the second is to directly reduce the low-poor iron ore, melt the reduced raw materials in an electric furnace, then add slag-making agents, separate molten iron and slag, and use the molten iron, but the slag will be discarded. For example, the Chinese patent named a low-carbon steelmaking method and system using low-grade direct reduced iron as raw material, the publication number is CN117535464A. This patent transfers liquid molten iron to an electric arc furnace or a converter for blowing into primary molten steel. The primary molten steel is directly cast on a continuous casting machine or refined by a refining device and then sent to a continuous casting machine for casting according to the requirements of the steel grade. Both the molten iron slag and the steel slag are transported to a slag treatment plant for treatment.

[0004] To this end, the present application provides a segmented smelting equipment for low-lean iron ore and an operating method thereof. Summary of the invention

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a segmented smelting equipment for low-lean iron ore and an operation method thereof, thereby solving the technical problems in the prior art of dependence on high-grade ore resources, inability to fully utilize low-lean iron ore, and slag being discarded.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a segmented smelting equipment for low-lean iron ore, including: a hydrogen vertical furnace; a smelting furnace, which is arranged below the hydrogen vertical furnace; a pellet inlet, which is arranged below the hydrogen vertical furnace and inserted into the side wall of the smelting furnace and connected with the smelting furnace; a retaining wall, which is arranged inside the smelting furnace, and the side of the retaining wall close to the hydrogen vertical furnace is the first-stage smelting furnace, and the side of the retaining wall away from the hydrogen vertical furnace is the second-stage smelting furnace; an air supply assembly, which is arranged on the side wall and bottom wall of the smelting furnace; a heating element, which is arranged on the top wall of the first-stage smelting furnace; a mechanical stirring, which is arranged inside the second-stage smelting furnace; a flux silo, which is arranged on the top of the first-stage smelting furnace and connected with the inside of the first-stage smelting furnace; a slag regulating agent silo, which is arranged above the second-stage smelting furnace; an iron outlet, which is opened on the side wall of the first-stage smelting furnace; and a slag outlet, which is opened on the side wall of the second-stage smelting furnace.

[0007] Optionally, the air supply assembly includes: a side-blowing lance, which is arranged on the side wall of the first-section smelting furnace and is connected with the interior of the first-section smelting furnace, and the insertion position of the side-blowing lance on the side wall of the smelting furnace is higher than the pellet inlet; the vertical depth of the insertion of the side-blowing lance is 1 / 3 to 1 / 2 of the thickness of the slag layer in the smelting furnace, and the vertical depth of the insertion of the pellet inlet is 1 / 2 to 1 of the thickness of the slag layer in the smelting furnace; a bottom-blowing lance, which is arranged at the bottom of the first-section smelting furnace and the second-section smelting furnace, and is connected with the interior of the first-section smelting furnace and the second-section smelting furnace.

[0008] Optionally, the total number of side-blowing spray guns is 3-9; along the width direction of the first-section melting furnace, 1-3 side-blowing spray guns are evenly arranged on the side wall of each first-section melting furnace; the insertion angle of the side-blowing spray gun is 0°-60°; 6-10 bottom-blowing spray guns are evenly arranged at the bottom of the first-section melting furnace, and 2-4 bottom-blowing spray guns are evenly arranged at the bottom of the second-section melting furnace.

[0009] Optionally, the height of the retaining wall is 3 to 8 times the depth of the molten iron layer in the first-stage smelting furnace.

[0010] Optionally, a dispersion nozzle is arranged between the slag conditioning agent silo and the second-stage smelting furnace to spray the slag conditioning agent into the second-stage smelting furnace; the number of the dispersion nozzles is 1-6.

[0011] Optionally, the dispersion nozzle includes: a nozzle outer cylinder, which is arranged below a slag adjusting agent bin and is communicated with the slag adjusting agent bin; a nozzle inner cylinder, which is arranged inside the nozzle outer cylinder, is connected to the nozzle outer cylinder, and is communicated with an air supply assembly through a pipeline, and a slag adjusting agent channel is formed between the nozzle inner cylinder and the nozzle outer cylinder; a flow guide is arranged inside the nozzle inner cylinder, is connected to the nozzle outer cylinder, and a gas channel is formed between the flow guide and the nozzle inner cylinder.

[0012] The deflector includes: an internal connector, which is arranged inside the nozzle inner cylinder and connected to the nozzle inner cylinder, and the lower edge of the internal connector is lower than the lower edge of the nozzle inner cylinder; a guide plate, which is a circular plate, is arranged at the bottom of the internal connector, so that an annular gas channel is formed between the lower edge of the nozzle inner cylinder and the edge of the guide plate, and the diameter of the guide plate is 1 to 1.5 times the diameter of the nozzle inner cylinder.

[0013] Optionally, the guide device also includes: the angle between the lower edge of the nozzle inner tube and the horizontal plane is ∠α, 0°≤∠α≤45°; the angle between the plane of the guide plate facing the nozzle inner tube and the side of the guide plate is ∠β, 135°≤∠β≤180°.

[0014] Optionally, a recovery system is arranged at one side of the hydrogen vertical furnace and is connected to the gas outlet of the hydrogen vertical furnace through a pipeline.

[0015] The second aspect of the present invention provides an operating method of a segmented smelting device for low-lean iron ore, which is used for the segmented smelting device for low-lean iron ore in the first aspect. The steps of the operating method specifically include:

[0016] S1: crushing and grinding the low-poor iron ore, and then manufacturing pellets;

[0017] S2: The pellets are preheated and sent to a hydrogen vertical furnace for pre-reduction, which produces furnace top gas and pre-reduced pellets;

[0018] S3: The top gas produced by pre-reduction passes through the recovery system, and the separated hydrogen is introduced into the melting furnace for reuse;

[0019] S4: The pre-reduced pellets enter the melting furnace through the pellet inlet:

[0020] In the first stage of the melting furnace, the pellets directly enter the slag, and the heat provided by the heating element and the hydrogen sprayed by the gas supply assembly further melt and reduce the pre-reduced pellets to obtain an upper layer of slag and a lower layer of molten iron;

[0021] The slag that is higher than the retaining wall flows into the second stage melting furnace, and the slag adjusting agent is added through the slag adjusting agent silo to adjust the composition, and the gas supply component and mechanical stirring are used for stirring. After the slag composition is uniform, it is discharged through the slag outlet;

[0022] The lower layer of molten iron is discharged through the taphole, realizing the comprehensive utilization of low-lean iron ore.

[0023] Optionally, in step S1, the low-lean iron ore includes: one or a combination of high-aluminum iron ore, low-grade iron ore, high-iron dust ash or high-iron alumina red mud.

[0024] The beneficial effects of the present invention are:

[0025] (1) Comprehensively utilizing existing low-grade iron ore resources or metallurgical solid waste to produce molten iron and high-value-added slag will help my country get rid of its high dependence on high-priced imported iron ore and improve production efficiency.

[0026] (2) According to the long-term experience of molten iron production process, in order to achieve a higher yield of iron elements, the ironmaking process has higher requirements for the slag-making system. By designing a two-stage smelting furnace, the slag-making system for producing molten iron in the first stage smelting furnace can be guaranteed, and the sensible heat of the slag can be used to continue to adjust the target slag in the second stage smelting furnace, and finally obtain two products, molten iron and target slag. The target slag is used as a raw material to further extract valuable elements or produce microcrystalline glass. In addition, by setting the smelting furnace as the first stage smelting furnace and the second stage smelting furnace, the sensible heat of the high-temperature slag can be fully utilized, the energy loss caused by the slag during transportation or complete cooling can be reduced, and the overall energy utilization rate of the segmented smelting equipment can be improved.

[0027] (3) Since the slag layer is the reaction space where the pellets are further reduced and melted, the present application limits the thickness of the slag layer in the smelting furnace by limiting the height of the retaining wall, thereby ensuring the reduction and melting effect of the pellets.

[0028] (4) In the first-stage melting furnace, a side-blowing lance is placed above the entrance of the pre-reduced pellets. The gas introduced by the side-blowing lance helps to evenly disperse the pellets in the slag, accelerates the melting and reaction rates, and solves the problem of the pellets floating on the surface of the slag layer and agglomerating in the prior art. Above the second-stage melting furnace, a dispersion nozzle is set so that a slag regulating agent bin can add small-particle slag regulating agents into the second-stage melting furnace through the dispersion nozzle, so that the slag regulating agents are evenly dispersed and fall into the melting furnace, thereby avoiding the reduction of the reaction rate and the melting rate caused by the agglomeration of the slag regulating agents, making full use of the volume of the melting furnace and improving the reaction efficiency.

[0029] (5) The present invention provides a side-blowing lance and a bottom-blowing lance of the gas supply assembly. On the one hand, hydrogen is used as a reducing agent. On the other hand, after the hydrogen enters the smelting furnace through the gas supply assembly, gas stirring can be performed in the smelting furnace, which not only effectively reduces the carbon emissions of the steel enterprise, but also increases the reaction rate in the smelting furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of the segmented smelting equipment of the present invention;

[0031] Figure 2 It is a schematic diagram of the structure of the dispersion nozzle of the present invention;

[0032] Figure 3 It is a schematic diagram of the process flow of the operating method of the segmented smelting equipment of the present invention.

[0033] Description of reference numerals:

[0034] 1. Hydrogen vertical furnace;

[0035] 2. Melting furnace; 21. First stage melting furnace; 22. Second stage melting furnace;

[0036] 3. Pellet entrance;

[0037] 4. Retaining wall;

[0038] 5. Air supply assembly; 51. Side blowing spray gun; 52. Bottom blowing spray gun;

[0039] 6. Heating element;

[0040] 7. Solvent silo;

[0041] 8. Mechanical stirring;

[0042] 9. Taphole;

[0043] 10. Slag outlet;

[0044] 11. Recovery system; 111. Filtering and dust removal device; 112. Heat exchange device; 113. Gas separation device; 114. Water electrolysis device; 115. Converging valve;

[0045] 12. Raw material warehouse;

[0046] 13. dispersion nozzle; 131. nozzle outer cylinder; 132. nozzle inner cylinder; 133. flow guide; 1331. internal connecting piece; 1332. flow guide plate;

[0047] 14. Slag conditioning agent silo;

[0048] 15. The second heat exchange device. DETAILED DESCRIPTION

[0049] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0050] Example:

[0051] This embodiment provides a segmented smelting equipment for low-lean iron ore, such as Figure 1As shown, it includes: a hydrogen vertical furnace 1; a smelting furnace 2, which is arranged below the hydrogen vertical furnace 1; a pellet inlet 3, which is arranged below the hydrogen vertical furnace 1 and inserted into the side wall of the smelting furnace 2 and is connected to the smelting furnace 2; a retaining wall 4, which is arranged inside the smelting furnace 2, and the side of the retaining wall 4 close to the hydrogen vertical furnace 1 is the first stage smelting furnace 21, and the side of the retaining wall 4 away from the hydrogen vertical furnace 1 is the second stage smelting furnace 22; a gas supply component 5, which is arranged on the side of the smelting furnace 2 wall and bottom wall; a heating element 6 is arranged on the top wall of the first-stage smelting furnace 21; a flux silo is arranged on the top of the first-stage smelting furnace 21 and is connected to the inside of the first-stage smelting furnace 21; a mechanical stirring 8 is arranged inside the second-stage smelting furnace 22; a slag regulating agent silo 14 is arranged above the second-stage smelting furnace 22; an iron outlet 9 is opened on the side wall of the first-stage smelting furnace 21; a slag outlet 10 is opened on the side wall of the second-stage smelting furnace 22.

[0052] In this embodiment, the raw material bin 12 is used to transport the pre-prepared pellets to the hydrogen vertical furnace 1, and the pellets are pre-reduced in the hydrogen vertical furnace 1. In the first-stage smelting furnace 21, the pre-reduced pellets are finally reduced by the hydrogen-rich gas transported by the gas supply component 5. The heat required by the smelting furnace 2 is provided by the heating element 6, and finally an upper layer of slag and a lower layer of molten iron are obtained; part of the upper layer of slag flows into the second-stage smelting furnace 22, and a small-particle slag regulating agent is added to the second-stage smelting furnace 22 by using the dispersion nozzle 13 on the top of the second-stage smelting furnace 22. The second-stage smelting furnace 22 is stirred by mechanical stirring 8 and blowing of the gas supply component 5 at the bottom, so that the added slag regulating agent is further evenly distributed in the second-stage smelting furnace 22 and can accelerate its reaction and melting speed, thereby realizing full utilization of the slag in the low-lean iron ore.

[0053] Exemplarily, the pre-reduced pellets are transported to the smelting furnace 2, i.e., the first-stage smelting furnace 21 and the second-stage smelting furnace 22, and are melted by electrode heating in the first-stage smelting furnace 21, and a reducing solvent is added to the first-stage smelting furnace 21 through the solvent silo 7, thereby completing the final reduction of the pellets, and the reduction temperature is 1450°C to 1650°C. The molten iron with a higher density is discharged through the iron outlet 9; the upper slag with a liquid level higher than the retaining wall 4 flows into the second-stage smelting furnace 22, and slag adjustment is performed in the second-stage smelting furnace 22, and slag adjustment agents are added to the second-stage smelting furnace 22 through the slag adjustment agent silo 14, and the gas supply component 5 and the mechanical stirring 8 are used to accelerate the melting and chemical reaction rate of the slag adjustment agent, and make the slag composition uniform, and the slag composition is uniform. After the slag composition is uniform, it is discharged through the slag outlet 10. Among them, the mechanical stirring 8 mainly stirs the middle and bottom of the second-stage smelting furnace 22, and the gas supply component 5 performs auxiliary stirring on the bottom of the second-stage smelting furnace 22 by supplying hydrogen, so that the slag in the second-stage smelting furnace 22 is evenly stirred, ensuring the efficient utilization of the slag in the low-lean iron ore.

[0054] Exemplarily, the height of the retaining wall 4 is 3-8 times the height of the molten iron layer in the first-stage smelting furnace 21, thereby ensuring that the molten iron is normally discharged through the iron outlet 9 on the side wall of the first-stage smelting furnace 21, and that the molten iron passes over the retaining wall 4 and enters the second-stage smelting furnace 22 is slag, so that the slag can be evenly stirred and slag-adjusted in the second-stage smelting furnace 22, and the slag directly enters the second-stage smelting furnace 22 for slag adjustment. This arrangement makes full use of the sensible heat of the slag itself, and avoids the possibility of impurities being mixed into the slag during transportation, thereby achieving efficient utilization of slag in low-lean iron ore.

[0055] In a possible embodiment, Figure 1 As shown, the air supply assembly 5 includes: a side-blowing lance 51, which is arranged on the side wall of the first-stage smelting furnace 21 and is connected with the interior of the first-stage smelting furnace 21, and the insertion position of the side-blowing lance 51 on the side wall of the smelting furnace 2 is higher than the pellet inlet 3; the vertical depth of the insertion of the side-blowing lance 51 is 1 / 3 to 1 / 2 of the thickness of the slag layer in the smelting furnace 2, and the vertical depth of the insertion of the pellet inlet 3 is 1 / 2 to 1 of the thickness of the slag layer in the smelting furnace 2; a bottom-blowing lance 52, which is arranged at the bottom of the first-stage smelting furnace 21 and the second-stage smelting furnace 22, and is connected with the interior of the first-stage smelting furnace 21 and the second-stage smelting furnace 22.

[0056] Exemplarily, under the premise of ensuring that the side-blowing lance 51 is placed above the pre-reduced pellet inlet 3, the vertical depth of the side-blowing lance 51 insertion is limited to 1 / 3 of the thickness of the slag layer in the smelting furnace 2, and the vertical depth of the pellet inlet 3 insertion is limited to 1 / 2 of the thickness of the slag layer in the smelting furnace 2, so that the gas introduced by the side-blowing lance 51 helps the pellets to be evenly dispersed in the slag. This arrangement will not affect the molten iron layer due to the vertical depth of the side-blowing lance 51 being too deep, nor will the effect of the gas introduced on the pellets be too small due to the vertical depth of the side-blowing lance 51 being too shallow, thereby ensuring that the gas introduced helps the pellets to be evenly dispersed in the slag, accelerating the melting and reaction rate of the pellets, and solving the technical problem of the pellets floating on the surface of the slag layer and agglomerating in the prior art.

[0057] Illustratively, by arranging the bottom blowing lance 52 at the bottom of the smelting furnace 2, that is, the bottom blowing lance 52 is arranged at the bottom of the first-stage smelting furnace 21 and the bottom of the second-stage smelting furnace 22, when the hydrogen passes through the smelting furnace 2, it not only serves as a reducing agent, but also the heat of the smelting furnace 2 can heat the gas, so that the hydrogen entering the hydrogen vertical furnace 1 has a certain temperature, and there is no need to supply additional heat for the hydrogen.

[0058] In a possible embodiment, Figure 1As shown, the total number of side-blowing spray guns 51 is 3 to 9; along the width direction of the first-section smelting furnace 21, 1 to 3 side-blowing spray guns 51 are evenly arranged on the side wall of each first-section smelting furnace 21; the insertion angle of the side-blowing spray gun 51 is 0° to 60°; 6 to 10 bottom-blowing spray guns 52 are evenly arranged at the bottom of the first-section smelting furnace 21, and 2 to 4 bottom-blowing spray guns 52 are evenly arranged at the bottom of the second-section smelting furnace 22.

[0059] For example, Figure 1 As shown, the number of side-blowing lances 51 in this embodiment is 3, which are arranged on the side wall of the first-stage melting furnace 21. The hydrogen sprayed by the side-blowing lance 51 not only plays a reducing role, but also can make the pellets evenly dispersed in the slag layer. The number of bottom-blowing lances 52 is 8, 6 of which are arranged at the bottom of the first-stage melting furnace 21, and 2 are evenly arranged at the bottom of the second-stage melting furnace 22. They are respectively arranged at the bottom of the first-stage melting furnace 21 and the bottom of the second-stage melting furnace 22. The hydrogen provided by the side-blowing lance 51 and the bottom-blowing lance 52 not only acts as a reducing gas, but also plays an auxiliary stirring role, which is conducive to improving the uniformity of the slag composition.

[0060] In a possible embodiment, Figure 1 As shown, the height of the retaining wall 4 is 3 to 8 times the depth of the molten iron layer in the first-stage smelting furnace 21 .

[0061] For example, by limiting the height of the retaining wall 4, it is ensured that the slag layer in the first stage smelting furnace 21 has a certain thickness, rather than the entire slag layer passing over the retaining wall 4 to enter the second stage smelting furnace 22. Because the slag layer is the reaction space for the pellets to be further reduced and melted, if the entire slag layer passes over the retaining wall 4, it will be detrimental to the reaction of the pellets. Therefore, the height of the retaining wall 4 is limited to 3 to 8 times the depth of the molten iron layer in the first stage smelting furnace 21, which not only reserves the reaction space for the pellets to be further reduced and melted, but also allows the slag that needs to be adjusted to enter the second stage smelting furnace 22.

[0062] In a possible embodiment, Figure 1 As shown, the dispersion nozzle 13 is disposed between the slag adjusting agent bin 14 and the second-stage smelting furnace 22 to spray the slag adjusting agent into the second-stage smelting furnace 22; the number of the dispersion nozzles 13 is 1-6.

[0063] Exemplarily, the number of the dispersion nozzles 13 in this embodiment is 4, and the 4 dispersion nozzles 13 are arranged along the length direction or the width direction of the second-stage smelting furnace 22, that is, the 4 dispersion nozzles 13 are arranged in a row along a straight line, thereby making full use of the internal volume of the second-stage smelting furnace 22, and adding small-particle slag adjusting agent into the second-stage smelting furnace 22 through the dispersion nozzles 13, so that the slag adjusting agent is evenly dispersed and falls into the second-stage smelting furnace 22.

[0064] Exemplarily, the number of the dispersion nozzles 13 in this embodiment is 5, and the 5 dispersion nozzles 13 are arranged along the circumferential direction of the discharge port below the slag adjusting agent silo 14, that is, the 5 dispersion nozzles 13 are arranged in a circle along the circumference of the discharge port, and the slag adjusting agent with small particle size is added into the second-stage smelting furnace 22 through the dispersion nozzles 13, so that the slag adjusting agent is evenly dispersed and falls into the second-stage smelting furnace 22.

[0065] In a possible embodiment, Figure 1 and Figure 2 As shown, the dispersion nozzle 13 includes: a nozzle outer cylinder 131, which is arranged below the slag adjusting agent bin 14 and is connected to the slag adjusting agent bin 14; a nozzle inner cylinder 132, which is arranged inside the nozzle outer cylinder 131, connected to the nozzle outer cylinder 131, and connected to the air supply component 5 through a pipeline, and a slag adjusting agent channel is formed between the nozzle inner cylinder 132 and the nozzle outer cylinder 131; a flow guide 133, which is arranged inside the nozzle inner cylinder 132, connected to the nozzle inner cylinder 132, and a gas channel is formed between the flow guide 133 and the nozzle inner cylinder 132, and the diameter of the flow guide plate 1332 is 1 to 1.5 times the diameter of the nozzle inner cylinder 132.

[0066] Exemplarily, the dispersion nozzle 13 in this embodiment is a cylindrical structure as a whole, and the nozzle outer tube 131, the nozzle inner tube 132, the guide device 133 and the slag regulating agent bin 14 can be welded. The dispersion nozzle 13 comprises, from the outside to the inside, a nozzle outer tube 131, a nozzle inner tube 132 and a guide vane 133. A slag regulating agent channel is located between the nozzle inner tube 132 and the nozzle outer tube 131, and a gas channel is formed between the guide vane 133 and the nozzle inner tube 132. That is, along the radial direction of the dispersion nozzle 13, the gas channel is arranged relatively inwardly, and the slag regulating agent channel is arranged relatively outwardly. The gas provided through the gas channel has a gas velocity of 20m / s-100m / s, and the slag regulating agent transported by the slag regulating agent channel is then sprayed and dispersed, which not only effectively utilizes the hydrogen recovered by the recovery system 11, but also more evenly disperses the slag regulating agent in the second-stage smelting furnace 22, allowing sufficient contact between the slag regulating agent and the slag, avoiding the reduction in reaction rate and melting rate caused by agglomeration of the slag regulating agent, and is beneficial to improving the reaction efficiency in the second-stage smelting furnace 22.

[0067] The deflector 133 includes: an internal connecting piece 1331, which is arranged inside the nozzle inner tube 132 and connected to the nozzle outer tube 131, and the lower edge of the internal connecting piece 1331 is lower than the lower edge of the nozzle inner tube 132; a guide plate 1332, which is a circular plate, is arranged at the bottom of the internal connecting piece 1331, and an annular gas channel is formed between the lower edge of the nozzle inner tube 132 and the edge of the guide plate 1332.

[0068] Exemplarily, the internal connecting member 1331 is in the shape of a long column, the guide plate 1332 is in the shape of a circular plate, the internal connecting member 1331 and the guide plate 1332 are welded together, and the nozzle inner cylinder 132 is arranged outside the internal connecting member 1331. Therefore, an annular gas channel is formed between the lower edge of the nozzle inner cylinder 132 and the edge of the guide plate 1332, which can provide blowing gas for the slag adjusting agent in the circumferential direction, thereby improving the uniform dispersion effect of the slag adjusting agent in the second-stage smelting furnace 22.

[0069] In a possible embodiment, Figure 2 As shown, the guide 133 also includes: the angle between the lower edge of the nozzle inner cylinder 132 and the horizontal plane is ∠α, 0°≤∠α≤45°; the angle between the plane of the guide plate 1332 facing the nozzle inner cylinder 132 and the side of the guide plate 1332 is ∠β, 135°≤∠β≤180°.

[0070] Exemplarily, through the above definition, the inclination angle of the edge of the guide plate 1332 and the inclination angle of the edge of the nozzle inner tube 132 are both closer to horizontal, which makes the angle of the gas sprayed in the annular gas channel between the guide plate 1332 and the nozzle inner tube 132 closer to horizontal, and the sprayed gas is sprayed out from the annular gas channel in a diffused state, so that the area of ​​the slag adjusting agent diffused by the sprayed gas in the horizontal direction is larger, and the slag adjusting agent will not directly enter the second stage smelting furnace 22 in the vertical direction, thereby improving the dispersion effect of the slag adjusting agent.

[0071] In a possible embodiment, Figure 1 As shown, the recovery system 11 is arranged at one side of the hydrogen vertical furnace 1 and is connected to the gas outlet of the hydrogen vertical furnace 1 through a pipeline.

[0072] Illustratively, by setting up the recovery system 11, the coal gas discharged from the hydrogen vertical furnace 1 can be recycled. On the one hand, the hydrogen in the coal gas can be separated and continued to be used as reducing gas, and circulated to the hydrogen vertical furnace 1 and the smelting furnace 2; on the other hand, its physical heat can be recovered, which reduces energy consumption and improves the overall economic benefits of the staged smelting equipment.

[0073] For example, Figure 1 As shown, the recovery system 11 of this embodiment includes: a filtering and dust removal device 111, which is connected to the top of the hydrogen vertical furnace 1 through a pipeline; a heat exchange device 112, which is arranged below the filtering and dust removal device 111 and is connected to the filtering and dust removal device 111 through a pipeline; a gas separation device 113, which is arranged below the heat exchange device 112 and is connected to the heat exchange device 112 through a pipeline; a confluence valve 115, which is arranged between the gas separation device 113 and the gas supply component 5; a water electrolysis device 114, which is arranged below the gas separation device 113, and is connected to the gas separation device 113 and the confluence valve 115 through a pipeline.

[0074] Exemplarily, the furnace top gas generated by pre-reduction is continuously processed by the filtering and dust removal device 111, the heat exchange device 112, and the gas separation device 113, and the waste heat is used in the pellet preheating process. The water vapor obtained after separation by the gas separation device 113 is passed through the water electrolysis device 114 to produce hydrogen, and the produced hydrogen is then combined with the hydrogen separated by the gas separation device 113 through the confluence valve 115, and then supplied to the bottom blowing lance 52 and the side blowing lance 51 of the smelting furnace 2, thereby realizing the recycling of the furnace top gas.

[0075] The embodiment of the present invention also provides an operation method of a segmented smelting device for low-lean iron ore, such as Figure 2 As shown, the operation method includes:

[0076] S1: crushing and grinding the low-poor iron ore, and then manufacturing pellets;

[0077] S11: crushing the low-lean iron ore into ore powder of 2mm to 5mm, and then grinding the ore powder, wherein the ore powder particles ground to less than 200 meshes account for more than 85% of the total ore powder;

[0078] S12: the mineral powder ground in step S11 is made into pellets by adding water through a disc pelletizing machine, and a binder such as bentonite, slaked lime, quicklime, modified starch, etc. is added during the manufacturing process;

[0079] The amount of binder added is 1%-5% of the total mass of the pellets to prevent the pellets from cracking.

[0080] S2: The pellets are preheated and sent to a hydrogen vertical furnace 1 for pre-reduction, which produces furnace top gas and pre-reduced pellets;

[0081] In step S2, the pre-reduction conditions are: the temperature is set at 700°C to 1050°C; the reduction time is 30 minutes to 180 minutes; and the metallization rate of the pre-reduced pellets is 40% to 90%.

[0082] S3: The top gas generated by the pre-reduction passes through the recovery system 11, and the separated hydrogen is introduced into the smelting furnace 2 for reuse;

[0083] S31: The furnace top gas is continuously processed by the filtering and dust removal device 111, the heat exchange device 112, and the gas separation device 113 in sequence;

[0084] S32: the waste heat obtained by the heat exchange device 112 is used for preheating the pellets in step S2;

[0085] S33: After separation by the gas separation device 113, water vapor and hydrogen are obtained, wherein the water vapor is used to produce hydrogen through the electrolytic cell, and the hydrogen separated by the gas separation device 113 and the hydrogen produced by electrolysis are combined through the confluence valve 115 and supplied to the gas supply component 5 of the smelting furnace 2;

[0086] S4: The pre-reduced pellets enter the melting furnace 2 through the pellet inlet 3:

[0087] In the first stage melting furnace 21, the pellets directly enter the slag, and the heat provided by the heating element 6 and the hydrogen sprayed by the gas supply assembly 5 further melt and reduce the pre-reduced pellets to obtain an upper layer of slag and a lower layer of molten iron;

[0088] The reduction temperature of the final reduction operation is 1450°C to 1650°C;

[0089] The slag with a height exceeding the retaining wall 4 flows into the second stage melting furnace 22, and the slag adjusting agent is added through the slag adjusting agent silo 14 to adjust the composition, and is stirred by the gas supply component 5 and the mechanical stirring 8. After the slag composition is uniform, it is discharged through the slag outlet 10;

[0090] The lower layer of molten iron is discharged through the tap hole 9, thus realizing the comprehensive utilization of low-lean iron ore.

[0091] In a possible embodiment, Figure 2 As shown, in step S1, the low-lean iron ore includes: one or a combination of high-aluminum iron ore, low-grade iron ore, high-iron dust ash or high-iron alumina red mud.

[0092] For example, depending on the specific type of low-lean iron ore, slag adjustment is performed in the second stage smelting furnace 22. If high-aluminum iron ore is used, self-pulverized calcium aluminate slag with C / A=1.4 and C / S=2.0 can be prepared for leaching and extracting aluminum; if low-grade iron ore or high-iron dust ash and other raw materials with low aluminum content are used, wollastonite slag with a silicon dioxide content of 50% to 58%, aluminum oxide of 7% to 9%, and calcium oxide of 16% to 24% can be prepared for the preparation of microcrystalline glass.

[0093] Illustratively, the method for comprehensive utilization of low-lean iron ore in this embodiment can widely utilize one or a combination of high-aluminum iron ore, low-grade iron ore, high-iron dust ash, and high-iron alumina red mud, including a variety of complex low-grade iron-containing raw materials, and does not require mineral processing. It has a low dependence on high-priced imported iron ore, can significantly reduce production costs, and realize the comprehensive utilization of low-lean iron ore.

[0094] Exemplarily, the particle size of the slag conditioning agent in this embodiment is less than 5 mm, and the slag conditioning agent includes: one or a combination of silica, quicklime, slaked lime, fluorite or iron tailings.

[0095] Illustratively, the binary basicity of the slag in this embodiment is 0.9 to 1.3.

[0096] For example, Figure 2As shown, in step S2, the pre-reduction conditions are: the temperature is set at 700°C to 1050°C; the reduction time is 30 minutes to 180 minutes; and the metallization rate of the pre-reduced pellets is 40% to 90%.

[0097] The smelting furnace 2 in the following embodiments 1 to 3 includes a first-stage smelting furnace 21 and a second-stage smelting furnace 22 , and therefore the smelting furnace is referred to as a two-stage smelting furnace 2 .

[0098] Embodiment 1:

[0099] Low-grade iron ore produced in Liaoning Province was used as raw material, which was crushed, ground, and then manufactured into pellets. The chemical composition of the pellets is shown in Table 1.

[0100] Table 1 Composition of low-grade iron ore pellets produced in Liaoning Province (wt%)

[0101]

[0102] Under stable production conditions, for every 4100kg of low-poor iron ore pellets added to the hydrogen shaft furnace 1, 3675kg of pre-reduced pellets with a temperature of 850°C and a metallization rate of 80% can be produced. 3675kg of metallized pellets are directly pressed into the slag of the two-stage smelting furnace 2 through the pellet inlet 3, and 4134kg of limestone and 2720kg of dolomite are added at the same time, which can produce about 6500kg of slag with a temperature of 1500°C and 1000kg of molten iron. The binary basicity of the slag is 1.15, and the slag composition is shown in Table 2. The hydrogen content of the coal gas produced at the gas outlet above the hydrogen shaft furnace 1 is about 60%. After being treated by the second heat exchange device 15, the 850°C coal gas is introduced into the hydrogen shaft furnace 1 as the reducing coal gas. About 250 kg of silica is added to the second stage melting furnace 22 as a slag adjusting agent, and stirred by using the gas supply component 5 and the mechanical stirring 8. After the reaction, about 6700 kg of microcrystalline glass primary slag can be obtained. The composition of the microcrystalline glass primary slag is shown in Table 3.

[0103] Table 2 Composition of initial slag after iron extraction from low-grade iron ore pellets produced in Liaoning Province (wt%)

[0104]

[0105] Table 3 Composition of low-grade iron ore slag glass-ceramics produced in Liaoning Province (wt%)

[0106]

[0107] Embodiment 2:

[0108] Low-grade iron ore produced in Sichuan Province was used as raw material, which was crushed, ground, and then manufactured into pellets. The chemical composition of the pellets is shown in Table 4.

[0109] Table 4 Composition of low-grade iron ore pellets produced in Sichuan Province (wt%)

[0110]

[0111] Under stable production conditions, 2800 kg of pre-reduced pellets with a temperature of 850°C and a metallization rate of 90% can be produced for every 3130 kg of low-poor iron ore pellets added to the hydrogen vertical furnace 1. 2800 kg of metallized pellets are directly pressed into the slag of the two-stage smelting furnace 2 through the pellet inlet 3, and 1200 kg of limestone and 720 kg of dolomite are added at the same time, so that about 2800 kg of slag with a temperature of 1500°C and 1000 kg of molten iron can be obtained. The binary basicity of the slag is 1.15, and the slag composition is shown in Table 5. The hydrogen content of the coal gas produced at the gas outlet above the hydrogen vertical furnace 1 is about 80%. After being treated by the second heat exchange device 15, the 850°C coal gas is obtained and introduced into the hydrogen vertical furnace 1 as the reducing coal gas. About 100 kg of silica is added to the second stage melting furnace 22 as a slag adjusting agent, and stirred by using the gas supply component 5 and the mechanical stirring 8. After the reaction, about 2900 kg of microcrystalline glass slag can be obtained. The composition of the microcrystalline glass slag is shown in Table 6.

[0112] Table 5 Composition of initial slag after iron extraction from low-grade iron ore pellets produced in Sichuan Province (wt%)

[0113]

[0114] Table 6 Composition of low-grade iron ore slag glass-ceramics produced in Sichuan Province (wt%)

[0115]

[0116] Embodiment 3:

[0117] High aluminum iron ore is used as raw material, crushed, ground, and then manufactured into pellets. The chemical composition of the pellets is shown in Table 7.

[0118] Table 7 High aluminum iron ore pellet composition (wt%)

[0119]

[0120] Under stable production conditions, 3,450 kg of pre-reduced pellets with a temperature of 850°C and a metallization rate of 90% can be produced for every 3,920 kg of high-aluminum iron ore pellets added to the hydrogen vertical furnace 1. 3,450 kg of metallized high-aluminum iron ore pellets are directly pressed into the slag of the two-stage smelting furnace 2 through the pellet inlet 3, and 2,450 kg of limestone, 2,890 kg of dolomite and 1,700 kg of silica are added at the same time, which can produce about 6,700 kg of slag with a temperature of 1,500°C and 1,000 kg of molten iron. The binary basicity of the slag is 1.15, and the slag composition is shown in Table 8. The hydrogen content of the coal gas produced at the gas outlet above the hydrogen vertical furnace 1 is about 80%. After being treated by the second heat exchange device 15, the 850°C coal gas is introduced into the hydrogen vertical furnace 1 as the reducing coal gas. About 2700 kg of quicklime is added to the second stage melting furnace 22 as a slag conditioning agent, and the gas supply assembly 5 and the mechanical stirring 8 are used for stirring. After the reaction, the ratio of CaO to SiO2 in the slag can reach 2, and the ratio of CaO to Al2O3 can reach 1.4, and about 9400 kg of self-powdering high-aluminum slag is obtained. The composition of the self-powdering high-aluminum slag is shown in Table 9. The slag can be self-powdered by the subsequent temperature control system, which is convenient for the subsequent aluminum extraction process.

[0121] Table 8: Composition of initial slag after iron extraction from high-aluminum iron ore pellets (wt%)

[0122]

[0123] Table 9 Composition of self-pulverized high-aluminum slag (wt%)

[0124]

[0125] In the above-mentioned Example 1, every 4100kg of low-grade iron ore pellets can produce not only 1000kg of molten iron, but also about 6700kg of microcrystalline glass slag after being processed by the segmented smelting equipment for low-lean iron ore and its operating method of this example; in Example 2, every 3130kg of low-grade iron ore pellets can produce 1000kg of molten iron and about 2900kg of microcrystalline glass slag; in Example 3, every 3920kg of high-aluminum iron ore pellets can produce 1000kg of molten iron and about 9400kg of self-pulverizing high-aluminum slag. Compared with the existing mature blast furnace ironmaking technology, the blast furnace uses high-grade iron ore. Usually, 250kg-500kg of slag will be produced for every 1000kg of molten iron produced. The blast furnace with a daily iron production of more than 10,000 tons may produce more than 4,000 tons of slag per day. However, this part of the slag is generally piled up as waste after water cooling or partially used as cement ingredients, concrete admixtures or made into slag bricks. During water cooling, not only the sensible heat of the blast furnace slag is lost, but also its added value is not fully improved. It can be seen that through the above-mentioned embodiments 1, 2 and 3, the slag in the low-lean iron ore is well comprehensively utilized through the segmented smelting equipment for low-lean iron ore and its operation method of this embodiment.

[0126] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0127] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0128] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A segmented smelting equipment for low-lean iron ore, characterized in that: include: Hydrogen vertical furnace; A smelting furnace, arranged below the hydrogen vertical furnace; A pellet inlet is arranged below the hydrogen vertical furnace and inserted into the side wall of the smelting furnace to communicate with the smelting furnace; A retaining wall is arranged inside the smelting furnace, the side of the retaining wall close to the hydrogen vertical furnace is the first stage smelting furnace, and the side of the retaining wall away from the hydrogen vertical furnace is the second stage smelting furnace; A gas supply assembly is arranged on the side wall and the bottom wall of the smelting furnace; A heating element is arranged on the top wall of the first-stage melting furnace; A flux silo is disposed on the top of the first-stage smelting furnace and is communicated with the interior of the first-stage smelting furnace; Mechanical stirring is provided inside the second-stage melting furnace; A slag conditioning agent silo is arranged above the second-stage smelting furnace; An iron outlet is provided on the side wall of the first-stage smelting furnace; The slag outlet is opened on the side wall of the second-stage smelting furnace.

2. The segmented smelting equipment for low-lean iron ore according to claim 1, characterized in that: The air supply assembly comprises: A side-blowing lance is disposed on the side wall of the first-stage melting furnace and is connected to the interior of the first-stage melting furnace, wherein the insertion position of the side-blowing lance on the side wall of the melting furnace is higher than the pellet inlet; The vertical depth of the side-blowing lance insertion is 1 / 3 to 1 / 2 of the thickness of the slag layer in the smelting furnace, and the vertical depth of the pellet inlet insertion is 1 / 2 to 1 of the thickness of the slag layer in the smelting furnace; The bottom blowing lance is arranged at the bottom of the first-stage melting furnace and the second-stage melting furnace, and is connected with the interior of the first-stage melting furnace and the second-stage melting furnace.

3. The segmented smelting equipment for low-lean iron ore according to claim 2, characterized in that: The total number of side-blowing spray guns is 3 to 9; Along the width direction of the first-stage melting furnace, 1 to 3 side-blowing spray guns are evenly arranged on the side wall of each first-stage melting furnace; The insertion angle of the side-blowing spray gun is 0°-60°; The bottom blowing spray guns are evenly arranged in 6 to 10 pieces at the bottom of the first-stage melting furnace, and 2 to 4 pieces are evenly arranged at the bottom of the second-stage melting furnace.

4. The segmented smelting equipment for low-lean iron ore according to claim 1, characterized in that: The height of the retaining wall is 3 to 8 times the depth of the molten iron layer in the first smelting furnace.

5. The segmented smelting equipment for low-lean iron ore according to claim 1, characterized in that: Also includes: A dispersion nozzle is disposed between the slag-adjusting agent bin and the second-stage smelting furnace to spray the slag-adjusting agent into the second-stage smelting furnace; The number of the dispersing nozzles is 1 to 6.

6. The segmented smelting equipment for low-lean iron ore according to claim 5, characterized in that: The dispersion nozzle comprises: The nozzle outer cylinder is arranged below the slag conditioning agent bin and is connected with the slag conditioning agent bin; The nozzle inner cylinder is arranged inside the nozzle outer cylinder, connected to the nozzle outer cylinder, and communicated with the air supply assembly through a pipeline, and a slag regulating agent channel is formed between the nozzle inner cylinder and the nozzle outer cylinder; A flow guide is arranged inside the nozzle inner cylinder and connected to the nozzle inner cylinder, and a gas channel is formed between the flow guide and the nozzle inner cylinder; The deflector comprises: An internal connecting piece is arranged inside the nozzle inner cylinder and connected to the nozzle inner cylinder, and a lower edge of the internal connecting piece is lower than a lower edge of the nozzle inner cylinder; The guide plate is a circular plate, which is arranged at the bottom of the internal connecting piece, so that an annular gas channel is formed between the lower edge of the nozzle inner tube and the edge of the guide plate, and the diameter of the guide plate is 1 to 1.5 times the diameter of the nozzle inner tube.

7. The segmented smelting equipment for low-lean iron ore according to claim 6, characterized in that: The deflector also includes: The angle between the lower edge of the nozzle inner tube and the horizontal plane is ∠α, 0°≤∠α≤45°; The angle between the plane of the guide plate facing the nozzle inner cylinder and the side surface of the guide plate is ∠β, and 135°≤∠β≤180°.

8. The segmented smelting equipment for low-lean iron ore according to claim 1, characterized in that: Also includes: The recovery system is arranged at one side of the hydrogen vertical furnace and is connected with the gas outlet of the hydrogen vertical furnace through a pipeline.

9. An operating method for a segmented smelting device for low-lean iron ore, used for the segmented smelting device for low-lean iron ore as claimed in any one of claims 1 to 8, characterized in that: The operation method comprises: S1: crushing and grinding the low-poor iron ore, and then manufacturing pellets; S2: The pellets are preheated and sent to a hydrogen vertical furnace for pre-reduction, which produces furnace top gas and pre-reduced pellets; S3: The top gas produced by pre-reduction passes through the recovery system, and the separated hydrogen is introduced into the melting furnace for reuse; S4: The pre-reduced pellets enter the melting furnace through the pellet inlet: In the first stage melting furnace, the required heat in the furnace is provided by the heating element, and the pre-reduced pellets are further melted and reduced by the hydrogen sprayed by the gas supply assembly. The high-temperature molten slag and iron are naturally separated due to their different densities to obtain the upper layer of molten slag and the lower layer of molten iron. The slag that is higher than the retaining wall flows into the second stage melting furnace, and the slag adjusting agent is added through the slag adjusting agent silo to adjust the composition, and the gas supply component and mechanical stirring are used for stirring. After the slag composition is uniform, it is discharged through the slag outlet; The lower layer of molten iron is discharged through the taphole, realizing the comprehensive utilization of low-lean iron ore.

10. The method for operating the segmented smelting equipment for low-lean iron ore according to claim 9, characterized in that: In the step S1, the low-lean iron ore includes: one or a combination of high-aluminum iron ore, low-grade iron ore, high-iron dust ash or high-iron alumina red mud.

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