Iron ore concentrate sintering method

Abstract

The invention relates to an iron ore concentrate sintering method, and belongs to the technical field of ferrous metallurgy sintering. The method comprises the steps that part of iron ore concentrate and a calcium flux are subjected to first mixing, and a first mixed material is obtained; carrying out compression molding on the first mixed material to obtain a molded block mass; the remaining iron ore concentrate, mineral-containing materials and auxiliaries are subjected to second mixing, and a second mixed material is obtained; the second mixed material is subjected to granulation, and granulated pellets are obtained; distributing the pelletized small balls above the formed block mass to obtain a material to be treated; and sintering the to-be-treated material to obtain the sintered ore. According to the method, the mode of combining sintering and briquetting is fully considered to improve the iron ore concentrate sintering and pelletizing process, so that the sintering and mineralizing performance of the iron ore concentrate is improved.

Description

Technical Field

[0001] The present application relates to the technical field of iron and steel metallurgy sintering, and in particular to a method for sintering iron ore concentrate. Background Art

[0002] Sintered ore is the main raw material for blast furnace ironmaking. In the process of blast furnace ironmaking in steel enterprises, more than 70% of iron ore needs to be sintered first. Sintering raw materials include fine-grained iron concentrate, coarse-grained iron ore powder, fuel, flux, return ore, etc. There are many types, and most of the iron ore after beneficiation is fine-grained iron concentrate. When sintering high-proportion concentrate, the high proportion of concentrate will lead to slower water diffusion in the granulation process, reduce the granulation effect, and also have an adverse effect on the permeability of the subsequent sintering material layer.

[0003] Therefore, there is an urgent need for a method for sintering iron ore concentrate to improve the performance of iron ore concentrate sintering. Summary of the invention

[0004] The present application provides a method for sintering iron ore concentrate to solve the following technical problem: how to improve the performance of sintering iron ore concentrate.

[0005] In a first aspect, the present application provides a method for sintering iron ore concentrate, the method comprising:

[0006] Mixing part of the iron ore concentrate with the calcium flux to obtain a first mixed material;

[0007] Pressing the first mixed material into a molded mass to obtain a molded mass;

[0008] The remaining iron ore concentrate, mineral-containing material and additives are mixed for a second time to obtain a second mixed material;

[0009] Granulating the second mixed material to obtain granulated pellets;

[0010] Distributing the granulated balls above the formed agglomerates to obtain a material to be processed;

[0011] The material to be processed is sintered to obtain sintered ore.

[0012] Optionally, the weight of the iron ore concentrate is ≥ 60% of the total weight of the first mixture and the second mixture.

[0013] Optionally, the weight of part of the iron ore concentrate is 6% to 12% of the total weight of the iron ore concentrate.

[0014] Optionally, the calcareous flux includes at least one of the following: limestone and dolomite.

[0015] Optionally, the basicity of the first mixed material is 1.2 to 1.6.

[0016] Optionally, the moisture content of the first mixed material is 5.0% to 7.0%.

[0017] Optionally, the pressing pressure is 0.3 t / mm to 0.5 t / mm.

[0018] Optionally, the strength of the formed agglomerates is ≥200N / agglomerate.

[0019] Optionally, the size of the formed mass is Φ10×h15mm to Φ15×h20mm.

[0020] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0021] The method for sintering iron ore provided in an embodiment of the present application comprises: first mixing part of the iron ore concentrate with a calcium flux to obtain a first mixed material; pressing the first mixed material to obtain a formed agglomerate; second mixing the remaining iron ore concentrate, mineral-containing material and additives to obtain a second mixed material; granulating the second mixed material to obtain granulated balls; distributing the granulated balls above the formed agglomerate to obtain a material to be processed; and sintering the material to be processed to obtain a sintered ore. Part of the iron ore concentrate is diverted and mixed with the calcium flux for the first time, which can reduce the content of fine-grained iron ore concentrate in the second mixed material, so that the second mixed material can have a suitable ratio of core particles to iron ore concentrate, and then the second mixed material is more evenly distributed, thereby achieving a good granulation effect; the first mixed material is pressed and formed into a molded agglomerate, which can avoid the re-firing of the sintered ore; the molded agglomerate is used as a base material, and the granulation balls are distributed above the molded agglomerate, and the good air permeability of the granulation balls and the good supporting performance of the molded agglomerate can be utilized. During the sintering process, the air flow can first pass through the ball layer, so that the fuel in the balls is fully burned to generate heat, and then the heat is transferred to the molded agglomerate below to promote the sintering of the molded agglomerate; at the same time, the liquid calcium ferrite produced by the balls during the sintering process can penetrate downward into the agglomerate, further enhancing the integrity and strength of the entire sintered ore; therefore, the molded agglomerate makes full use of the automatic heat storage effect of the granulation balls, and the molded agglomerate is located at the bottom under high heat conditions, which is conducive to the oxidation and mineralization of the molded agglomerate. In summary, the performance of iron ore sintering is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1 A schematic flow chart of a method for sintering iron ore concentrate provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0026] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0027] In this application, unless otherwise specified, the directional words used, such as "upper" and "lower", refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of this application, the terms "include", "comprise", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0028] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0029] At present, the main methods for strengthening the sintering of high-proportion concentrates are strengthening the granulation process and diverting the treatment of difficult-to-granulate concentrates. The strengthening granulation process is to use strong mixing and other processes to improve the mixing effect of the sintering raw materials and strengthen the subsequent granulation process. This process can reduce the powder loss rate of the sintered mixture after granulation and improve the air permeability of the sintered material layer. Diverting treatments include pre-wetting fine-grained concentrates, partial pre-granulation, and small ball sintering, all of which play a certain role in strengthening the sintering of fine concentrates. However, the above processes have not considered the combination of sintering and briquetting to improve the sintering granulation process of fine concentrates. Therefore, in the first aspect, the present application provides a method for sintering iron concentrates. Figure 1 A schematic diagram of a method for sintering iron ore concentrate provided in an embodiment of the present application; see Figure 1 , the method comprising:

[0030] S1. performing a first mixing of a portion of the iron ore concentrate and a calcium flux to obtain a first mixed material;

[0031] In some embodiments, the weight of the iron ore concentrate is ≥ 60% of the total weight of the first mixed material and the second mixed material.

[0032] In some embodiments, the weight of the portion of the iron ore concentrate is 6% to 12% of the total weight of the iron ore concentrate.

[0033] In the embodiment of the present application, the weight of the iron concentrate is ≥60% of the total weight of the first mixed material and the second mixed material, which plays a role in strengthening the sintering of the high-proportion concentrate. For example, the weight of the iron concentrate can be 60%, 61%, 62%, 63%, 64%, 65%, 66%, etc. of the total weight of the first mixed material and the second mixed material.

[0034] Part of the iron concentrate is used for forming agglomerates, and part of it is used for pelletizing. The iron concentrate is an adhesive powder with a particle size of -0.5 mm, so it has a certain adhesiveness. The iron concentrate used for pelletizing is 88% to 94% of the total weight of the iron concentrate. A large amount of iron concentrate is concentrated for pelletizing to achieve efficient pelletizing. The weight of part of the iron concentrate can be 6% to 12% of the total weight of the iron concentrate, so as to balance the calcium-iron molar ratio and the core-powder ratio (the ratio of core particles to adhesive powder) of the pelletizing process. The exemplary weight of this part of the iron concentrate can be 6%, 7%, 8%, 9%, 10%, 11%, 12%, etc. of the total weight of the iron concentrate.

[0035] In some embodiments, the calcareous flux includes at least one of the following: limestone and dolomite.

[0036] In the embodiment of the present application, the calcium flux can ensure the basicity of the formed agglomerates. Exemplarily, the calcium flux can be one or both of limestone and dolomite.

[0037] In some embodiments, the basicity of the first mixed material is 1.2-1.6.

[0038] In the embodiment of the present application, the basicity of the first mixed material can be 1.2 to 1.6, so that the subsequent formed agglomerates have suitable basicity and calcium-iron molar ratio, which is conducive to the formation of calcium ferrite liquid phase, and has a good forming effect and the effect of serving as a base material for subsequent sintering. Exemplarily, the basicity of the first mixed material can be 1.2, 1.3, 1.4, 1.5, 1.6, etc.

[0039] In some embodiments, the moisture content of the first mixed material is 5.0% to 7.0%.

[0040] In the embodiment of the present application, the moisture content of the first mixed material can be 5.0% to 7.0%, so as to ensure the molding effect of the first mixed material and then ensure the strength of the subsequent formed agglomerates. Exemplarily, the moisture content of the first mixed material can be 5.0%, 5.2%, 5.4%, 5.6%, 5.8%, 6.0%, 6.2%, 6.4%, 6.6%, 6.8%, 7.0%, etc.

[0041] S2, pressing and molding the first mixed material to obtain a molded mass;

[0042] In some embodiments, the compression molding pressure is 0.3 t / mm to 0.5 t / mm.

[0043] In the embodiment of the present application, the pressure of the pressing molding can be 0.3t / mm to 0.5t / mm, which can make the formed agglomerate have suitable strength. The pressure of the pressing molding can be 0.3t / mm, 0.35t / mm, 0.4t / mm, 0.45t / mm, 0.5t / mm, etc.

[0044] In some embodiments, the strength of the formed agglomerates is ≥200N / piece.

[0045] In the embodiments of the present application, the strength of the formed blocks can be 200 N / piece, 205 N / piece, 210 N / piece, 215 N / piece, 220 N / piece, 225 N / piece, etc.

[0046] In some embodiments, the size of the formed agglomerates is Φ10×h15mm to Φ15×h20mm.

[0047] In the embodiments of the present application, the sizes of the formed blocks may be Ф10×h15mm, Ф11×h16mm, Ф12×h17mm, Ф13×h18mm, Ф14×h19mm, or Ф15×h20mm.

[0048] S3, performing a second mixing on the remaining iron ore concentrate, mineral-containing material and additive to obtain a second mixed material;

[0049] S4, granulating the second mixed material to obtain granulated balls;

[0050] In the embodiment of the present application, the mineral-containing material may include coarse-grained iron ore powder and return ore, and the auxiliary agent may include fuel and flux, and the flux is generally quicklime, and the coarse-grained iron ore powder and iron concentrate are both classified as iron ore. Part of the iron concentrate is shunted and mixed with the calcium flux for the first time, which can reduce the content of iron concentrate (-0.5mm particle size adhesion powder) in the second mixed material, so that the second mixed material can have a suitable ratio of core particles to iron concentrate, and then the second mixed material is more evenly distributed, so as to achieve a good granulation effect. The above-mentioned partial concentrate is shunted, so that more quicklime enters the mixed granulation process, and the granulation ball (metallogenic area alkalinity) is controlled at a higher level, so that the sintering process metallogenic area (adhesion layer) CaO / Fe2O3 molar ratio tends to a normal level, accelerates the generation of calcium ferrite liquid phase in the sintering mineralization process, strengthens the sintering mineralization process, thereby helping to improve the sintering yield and reduce energy consumption.

[0051] S5, distributing the granulated balls above the formed agglomerates to obtain materials to be processed;

[0052] In an embodiment of the present application, the first mixed material is pressed and formed into a molded agglomerate, which can avoid the re-firing of the sintered ore; the molded agglomerate is used as a base material, and the granulated balls are distributed above the molded agglomerate, making full use of the good air permeability of the granulated balls and the good supporting performance of the molded agglomerate. During the sintering process, the air flow can first pass through the ball layer, so that the fuel in the balls can be fully burned to generate heat, and then the heat is transferred to the molded agglomerate below, promoting the sintering of the molded agglomerate; at the same time, the liquid calcium ferrite produced by the balls during the sintering process can penetrate downward into the molded agglomerate, further enhancing the integrity and strength of the entire sintered ore.

[0053] S6. Sintering the material to be processed to obtain sintered ore.

[0054] In the embodiment of the present application, sintering the above-mentioned material to be processed having a layered material structure in which granulation balls are distributed above the formed agglomerates is beneficial to improving the sintering yield, reducing sintering energy consumption and solving the problem of re-burning of sintered ore, and the above-mentioned iron concentrate is used for diversion molding, which helps to maintain an appropriate core particle ratio in the granulation process and strengthen the sintering granulation process. Therefore, the iron concentrate can play a role in strengthening the sintering mineralization process as an adhesion layer, thereby improving the yield and quality of the sintered ore.

[0055] In summary, the method for sintering iron ore concentrate provided in this application has the following advantages:

[0056] 1. Improved granulation effect

[0057] The diversion and mixing of part of the iron concentrate reduces the content of fine-grained iron concentrate in the second mixed material, ensures a proper ratio of core particles to iron concentrate, makes the second mixed material more evenly distributed, and finally achieves a good granulation effect. A good granulation effect is conducive to improving the quality and performance of sintered ore, such as improving air permeability and material reactivity.

[0058] 2. Avoid re-burning

[0059] The shaped agglomerates obtained by pressing the first mixed material can avoid the phenomenon of re-firing of the sintered ore. Re-firing may cause the quality of the sintered ore to deteriorate, and cause structural damage, uneven composition and other problems. This characteristic of the shaped agglomerates helps to maintain the stable performance of the sintered ore.

[0060] 3. Heat transfer and utilization

[0061] The good air permeability of pellets and the good support performance of the formed agglomerates work together during the sintering process. The airflow first passes through the pellet layer to fully burn the fuel, and the generated heat is transferred to the formed agglomerates below. This heat transfer mechanism improves the heat utilization efficiency and makes the entire sintering process more stable and efficient.

[0062] 4. Enhance the integrity and strength of sintered ore

[0063] The liquid calcium ferrite produced by the pellets during the sintering process penetrates downward into the agglomerate, further enhancing the integrity and strength of the entire sintered ore. This means that the sintered ore is less likely to break during subsequent transportation and use, improving its durability and quality.

[0064] 5. Oxidation and mineralization of formed masses

[0065] The formed agglomerates make full use of the automatic heat storage effect of the granulating balls, which is conducive to the oxidation and mineralization of the formed agglomerates under the condition of being located at the bottom and with high heat, further optimizing the performance of the sintered ore and improving the conversion efficiency and quality of the iron ore.

[0066] In summary, this iron ore concentrate sintering method improves the performance of iron ore concentrate sintering in many aspects, such as granulation effect, avoiding re-firing, heat utilization and enhancing the strength of sintered ore, through the synergistic effect of various steps.

[0067] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for the unrecorded specific conditions in the following examples are usually measured according to national standards. If there is no corresponding national standard, then carry out according to general international standards, normal conditions or according to the conditions recommended by the manufacturer.

[0068] A method for sintering iron ore concentrate provided in an embodiment of the present application comprises:

[0069] S11, performing a first mixing of a portion of the iron ore concentrate and a calcium flux to obtain a first mixed material;

[0070] S21, pressing and molding the first mixed material to obtain a molded mass;

[0071] S31, performing a second mixing on the remaining iron ore concentrate, the mineral-containing material and the additive to obtain a second mixed material; wherein the mineral-containing material is iron ore powder and return ore, and the additive is fuel and quicklime;

[0072] S41, granulating the second mixed material to obtain granulated balls;

[0073] S51, distributing the granulated balls above the formed agglomerates to obtain materials to be processed;

[0074] S61, sintering the material to be processed to obtain sintered ore. Please refer to Table 1 for the raw material composition of the sintering in the embodiment, and Table 2 for the process parameters of the pressing and forming.

[0075] Table 1 Composition of raw materials for sintering of the embodiment

[0076]

[0077]

[0078] Table 2 Briquetting process parameters

[0079] Serial number Raw material alkalinity Mixed material moisture / % Pressing machine pressure / t / mm Agglomerate strength / N Example 1 1.3 6.0 0.4 263 Example 2 1.6 6.0 0.4 329 Example 3 1.9 6.0 0.4 287

[0080] Comparative Example

[0081] The present application provides a method for sintering an iron ore concentrate, comprising:

[0082] The iron ore concentrate, mineral-containing materials and additives are mixed to obtain a mixed material; wherein the mineral-containing materials are iron ore powder and return ore, and the additives are fuel and quicklime;

[0083] Granulating the mixed material to obtain granulated balls;

[0084] The pelletized balls are distributed on the top of the sintered ore to obtain the material to be processed;

[0085] The material to be processed is sintered to obtain sintered ore. Please refer to the raw material composition of the sintering of the comparative example shown in Table 3.

[0086] Table 3 Composition of sintered raw materials for comparative example

[0087]

[0088] The properties of the sintered ores prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested, see Table 4.

[0089] Table 4 Properties of sintered ore

[0090]

[0091]

[0092] It can be seen from Table 4 that the embodiments of the present application fully consider the combination of sintering and briquetting to improve the sintering and granulation process of iron ore concentrate, thereby improving the performance of sintering and mineralization of iron ore concentrate.

[0093] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0094] (1) By diverting part of the iron ore concentrate, the proportion of iron ore concentrate in the pelletizing balls to the total raw materials is reduced, so that the high-proportion concentrate can have a suitable ratio of core particles to adhesive powder during the pelletizing process, and the material distribution is more uniform, thereby achieving a good pelletizing effect.

[0095] (2) By diverting part of the iron ore concentrate, more quicklime can be introduced into the mixed granulation process, and the alkalinity of the mineralization area can be controlled at a higher level, so that the CaO / Fe2O3 molar ratio in the mineralization area (adhesion layer) of the sintering process tends to a normal level, accelerating the formation of calcium ferrite liquid phase in the sintering mineralization process, strengthening the sintering mineralization process, and being conducive to improving the sintering yield and reducing energy consumption;

[0096] (3) By diverting part of the concentrate, adding calcium flux to the pelletizing process, and replacing the base material with agglomerates of suitable size, the problem of excessive adhesion powder in the sintering process of high-proportion concentrate is solved. Replacing the base material can also solve the problem of re-firing of sintered ore. The pelletizing agglomerates make full use of the heat storage function of the pelletizing balls. The pelletizing agglomerates are located at the bottom under high heat conditions, which is conducive to the oxidation and mineralization of the pellets.

[0097] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for sintering iron ore concentrate, the method comprising: Mixing part of the iron ore concentrate with the calcium flux to obtain a first mixed material; Pressing the first mixed material into a molded mass to obtain a molded mass; The remaining iron ore concentrate, mineral-containing material and additives are mixed for a second time to obtain a second mixed material; Granulating the second mixed material to obtain granulated pellets; Distributing the granulated balls above the formed agglomerates to obtain a material to be processed; The material to be processed is sintered to obtain sintered ore.

2. The method according to claim 1, characterized in that The weight of the iron ore concentrate is ≥60% of the total weight of the first mixed material and the second mixed material.

3. The method according to claim 1, characterized in that The weight of part of the iron ore concentrate is 6% to 12% of the total weight of the iron ore concentrate.

4. The method according to claim 1, characterized in that: The calcareous flux comprises at least one of the following: limestone and dolomite.

5. The method according to claim 1 or 4, characterized in that: The basicity of the first mixed material is 1.2-1.

6.

6. The method according to claim 1, characterized in that The moisture content of the first mixed material is 5.0% to 7.0%.

7. The method according to claim 1, characterized in that The pressure of the pressing molding is 0.3 t / mm to 0.5 t / mm.

8. The method according to claim 1 or 7, characterized in that: The strength of the formed agglomerates is ≥200N / piece.

9. The method according to claim 1, characterized in that: The size of the formed agglomerate is Φ10×h15mm to Φ15×h20mm.

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