A method for pre-wetting sintering materials using pipeline concentrate

Abstract

This invention relates to the field of iron ore agglomeration, specifically disclosing a method for pre-wetting sintering materials using pipeline concentrate. The method includes the following steps: adding iron concentrate, sintering return ore, blast furnace return ore, dust collector ash, and gas ash to a mixer and stirring to obtain a premixed material; performing a primary and secondary mixing and granulation of the premixed material and other ingredients to obtain a mixture, which is then sintered. After implementation of this invention, ultra-large particles in the sintered mixture disappear, the proportion of particles larger than 8mm is significantly reduced, the proportion of particles smaller than 1mm is reduced, the proportion of intermediate-sized particles in the mixture increases significantly, the proportion of particles larger than 3mm increases somewhat, the proportion of particles in the 3-5mm range increases significantly, the overall particle size increases, particle size uniformity improves, and the air permeability index of the mixture is significantly improved.

Description

Technical Field

[0001] This invention specifically relates to the field of iron ore agglomeration, and more specifically to a method for pre-wetting sintering materials using pipeline concentrate. Background Technology

[0002] During the sintering and granulation process, the capillary force generated by capillary water is mainly used as the binding force. However, the capillary water needs time to absorb water. Dry materials such as sintering return ore, blast furnace return ore, and dust removal ash are directly added to the cylindrical granulator. Due to the short capillary water absorption time, the total capillary water content in the mixture is affected, which will reduce the granulation performance of the mixture.

[0003] When pipeline concentrate, a material with very high moisture content, is directly added to a cylindrical pellet mill, it preferentially combines with and digests the activated ash inside the mill, forming an ultra-high alkalinity mixture with pelletizing performance far exceeding that of a mixture mainly composed of pipeline concentrate and activated ash. This mixture then rapidly grows into ultra-large particles. These ultra-large particles are not only difficult to burn through during sintering, negatively impacting the sinter drum index, but they also significantly increase the alkalinity difference between different particle sizes, reducing the alkalinity and silicon-calcium levels of the suitable particle size for the sintered mixture, thereby affecting the quality and technical indicators of the sintered ore.

[0004] Pipeline transportation is a cost-effective medium- and short-distance iron concentrate transportation method in inland areas compared to road and rail transportation. How to better utilize pipeline concentrate and eliminate its negative impact on the sintering process is of great practical significance. Summary of the Invention

[0005] The purpose of this invention is to provide a method for pre-wetting sintering materials using pipeline concentrate, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for pre-wetting sintering materials using pipeline concentrate includes the following steps:

[0008] Step 1: Add iron concentrate, sintered return ore, blast furnace return ore, dust collector ash and gas ash to a mixer and mix to obtain a premixed homogeneous material;

[0009] Step 2: After mixing the premixed material and the ingredients once and twice, granulate the mixture to obtain the mixture, and then sinter the mixture.

[0010] As a further aspect of the present invention: in step one, the moisture content of the iron concentrate is 10%-15%.

[0011] As a further embodiment of the present invention: in step one, the moisture content of the sintered return ore is 0%; the moisture content of the blast furnace return ore is 0%; and the moisture content of the dust collector ash is 0%.

[0012] As a further aspect of the present invention: in step one, the moisture content of the gas ash is 3%-4%.

[0013] As a further embodiment of the present invention: in step one, the mass ratio of iron concentrate, sinter return ore, blast furnace return ore, dust removal ash, and gas ash is (30-50):(20-30):(20-30):(0-2):(0-4).

[0014] As a further aspect of the present invention: in step one, the moisture content of the premixed material is 5%-7%.

[0015] As a further aspect of the present invention: in step one, the iron concentrate is pipeline concentrate, which includes Baima concentrate and Pingchuan concentrate.

[0016] As a further aspect of the present invention: in step two, the ingredients include Australian ore, screened material, coke powder, 58% high-quality ore, limestone and activated ash.

[0017] As a further embodiment of the present invention: in step two, the first mixing time is 5 minutes and the second mixing and granulation time is 5 minutes.

[0018] As a further aspect of the present invention: In step two, the method for sintering the mixture is as follows: the mixture is spread on a sintering trolley, with a base material of 3 kg, a base material particle size of 10-16 mm, a material layer thickness of 750 mm, and the ignition temperature controlled at 1050℃, the ignition time at 2 min, the ignition negative pressure at 6 kPa, and the sintering negative pressure at 12 kPa.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: After implementation of the present invention, the ultra-large particles in the sintering mixture disappear, the proportion of particles larger than 8mm is significantly reduced, the proportion of particles smaller than 1mm is reduced, the proportion of intermediate particles in the mixture is significantly increased, the proportion of particles larger than 3mm is somewhat increased, the proportion of particles in the 3-5mm range is significantly increased, the overall particle size is larger, and the particle size uniformity is improved. The permeability index (JPU) of the mixture is significantly improved. The yield of sintered ore, the drum index, and the sintering utilization coefficient are all significantly improved, and the overall technical and economic indicators of sintering are significantly improved. The stability rates of TFe, FeO, and R0 in sintered ore are all improved to varying degrees, especially the improvement in the R0 stability rate is particularly significant. Overall, the present invention has significant effects on strengthening the granulation of sintering mixtures and improving the quality indicators of sintered ore. Attached Figure Description

[0020] Figure 1 This is a flowchart of a method for pre-wetting sintering materials using pipeline concentrate. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] When pipeline concentrate, a material with very high moisture content, is directly added to a cylindrical granulator, it preferentially combines with and digests activated ash within the granulator, forming an ultra-high alkalinity mixture with granulation performance far exceeding that of a mixture mainly composed of pipeline concentrate and activated ash. This mixture then rapidly grows into ultra-large particles. These ultra-large particles not only have difficulty being fully burned during sintering, negatively impacting the drum index of the sinter, but also significantly increase the alkalinity difference between different particle sizes, reducing the suitable alkalinity and silica-calcium levels for the sintered mixture, thus affecting the quality and technical indicators of the sintered ore. Pipeline transportation is a cost-effective method for transporting iron concentrate over short to medium distances in inland areas compared to road and rail transport. Therefore, how to better utilize pipeline concentrate and eliminate its negative impact on the sintering process is of significant practical importance.

[0023] Based on this, please refer to Figure 1 A method for pre-wetting sintering materials using pipeline concentrate includes the following steps: Step 1: Iron concentrate with a moisture content of 10%-15% is added to a mixer along with sintering return ore with a moisture content of 0%, blast furnace return ore with a moisture content of 0%, dust collector ash with a moisture content of 0%, and gas ash with a moisture content of 3%-4% at a mass ratio of (30-50):(20-30):(20-30):(0-2):(0-4). After mixing, a premixed material is obtained, wherein the moisture content of the premixed material is 5%-7%.

[0024] Furthermore, in step one, the iron concentrate is pipeline concentrate, including Baima concentrate and Pingchuan concentrate. Step two involves primary and secondary mixing and granulation of this premixed material and the batching materials to obtain a mixture. This mixture is then sintered. Primary mixing is used to mix the premixed material with the batching materials, wet it, and preheat it. Secondary mixing is used to granulate the moistened and mixed sintered material and add moisture. In addition, the batching materials include Australian ore, undersize material, coke powder, 58% high-quality ore, limestone, and activated ash. The specific batching scheme is shown in Table 1.

[0025] Table 1

[0026]

[0027]

[0028] In addition, during the mixing and granulation process, the first mixing time is 5 minutes and the second mixing and granulation time is 5 minutes.

[0029] Furthermore, in step two, the method for sintering the mixture is as follows: the mixture is spread on the sintering trolley, with a base material of 3 kg, a base material particle size of 10-16 mm, a material layer thickness of 750 mm, and the ignition temperature controlled at 1050℃, the ignition time at 2 min, the ignition negative pressure at 6 kPa, and the sintering negative pressure at 12 kPa.

[0030] Example 1

[0031] In this embodiment of the invention, a method for pre-wetting sintering materials using pipeline concentrate includes the following steps:

[0032] Step 1: Add pipeline concentrate with a moisture content of 10.5% and sintered return ore with a moisture content of 0%, blast furnace return ore with a moisture content of 0%, dust collector ash with a moisture content of 0%, and gas ash with a moisture content of 3.7% to a mixer in a mass ratio of (30-50):(20-30):(20-30):(0-2):(0-4). After mixing, a premixed material with a moisture content of 6.1% is obtained.

[0033] Step 2: After mixing the premixed material and the ingredients once and twice, granulation is performed to obtain a mixture. The mixture is then sintered. The ingredients include Australian ore, undersize material, coke powder, 58% high-quality ore, limestone, and activated ash.

[0034] In addition, during the mixing and granulation process, the first mixing time is 5 minutes and the second mixing and granulation time is 5 minutes.

[0035] Furthermore, in step two, the method for sintering the mixture is as follows: the mixture is spread on the sintering trolley, with a base material of 3kg, a base material particle size of 10-16mm, a material layer thickness of 750mm, an ignition temperature of 1050℃, an ignition time of 2min, an ignition negative pressure of 6kPa, and a sintering negative pressure of 12kPa.

[0036] Example 2

[0037] In this embodiment of the invention, a method for pre-wetting sintering materials using pipeline concentrate includes the following steps:

[0038] Step 1: Pipeline concentrate with a moisture content of 12.3% is added to a mixer along with sintered return ore with a moisture content of 0%, blast furnace return ore with a moisture content of 0%, dust collector ash with a moisture content of 0%, and gas ash with a moisture content of 3.7% at a mass ratio of (30-50):(20-30):(20-30):(0-2):(0-4). After mixing, a premixed material is obtained with a moisture content of 6.6%.

[0039] Step 2: After mixing the premixed material and the ingredients once and twice, granulation is performed to obtain a mixture. The mixture is then sintered. The ingredients include Australian ore, undersize material, coke powder, 58% high-quality ore, limestone, and activated ash.

[0040] In addition, during the mixing and granulation process, the first mixing time is 5 minutes and the second mixing and granulation time is 5 minutes.

[0041] Furthermore, in step two, the method for sintering the mixture is as follows: the mixture is spread on the sintering trolley, with a base material of 3kg, a base material particle size of 10-16mm, a material layer thickness of 750mm, an ignition temperature of 1050℃, an ignition time of 2min, an ignition negative pressure of 6kPa, and a sintering negative pressure of 12kPa.

[0042] Example 3

[0043] In this embodiment of the invention, a method for pre-wetting sintering materials using pipeline concentrate includes the following steps:

[0044] Step 1: Pipeline concentrate with a moisture content of 14.7% is added to a mixer along with sintered return ore with a moisture content of 0%, blast furnace return ore with a moisture content of 0%, dust collector ash with a moisture content of 0%, and gas ash with a moisture content of 3.7% at a mass ratio of (30-50):(20-30):(20-30):(0-2):(0-4). After mixing, a premixed material is obtained with a moisture content of 7.0%.

[0045] Step 2: After mixing the premixed material and the ingredients once and twice, granulation is performed to obtain a mixture. The mixture is then sintered. The ingredients include Australian ore, undersize material, coke powder, 58% high-quality ore, limestone, and activated ash.

[0046] In addition, during the mixing and granulation process, the first mixing time is 5 minutes and the second mixing and granulation time is 5 minutes.

[0047] Furthermore, in step two, the method for sintering the mixture is as follows: the mixture is spread on the sintering trolley, with a base material of 3kg, a base material particle size of 10-16mm, a material layer thickness of 750mm, an ignition temperature of 1050℃, an ignition time of 2min, an ignition negative pressure of 6kPa, and a sintering negative pressure of 12kPa.

[0048] Comparative Example 1

[0049] In the comparative example, the sintering virgin material and the returned ore were added together to the first mixing and granulation process, and then entered the second mixing process to obtain the sintering mixture. The moisture content of the sintering virgin material and the returned ore was the same as that in Example 1.

[0050] Comparative Example 2

[0051] In the comparative example, the sintering virgin material and the returned ore were added together to the first mixing and granulation process, and then entered the second mixing process to obtain the sintering mixture. The moisture content of the sintering virgin material and the returned ore was the same as that in Example 2.

[0052] Comparative Example 3

[0053] In the comparative example, the sintering virgin material and the returned ore were added together to the first mixing and granulation process and then entered the second mixing process to obtain the sintering mixture. The moisture content of the sintering virgin material and the returned ore was the same as that in Example 3.

[0054] The air permeability index of the sintered metal in Examples 1-3 was calculated using the following formula: In the formula, JPU represents the permeability index of the material layer, which is the gas flow rate per unit area under a unit pressure gradient; Q represents the air volume passing through the material layer, in m3 / min; A represents the grate area, in m2; h represents the material layer height, in mm; Δp represents the material layer resistance, in Pa; and n represents the coefficient, which is taken as 0.6.

[0055] The JPU of the sintered mixture was measured using a sintered mixture permeability measuring device. The container holding the mixture had an inner diameter of 95 mm and a material layer height of 300 mm. Q and Δp were automatically recorded by the device, and the JPU of the mixture was automatically calculated. The particle size distribution and JPU of the mixture are shown in Table 2. The technical and economic indicators and component stability of the sintered ore are shown in Tables 2-4.

[0056] Table 2

[0057]

[0058] Table 3

[0059] name Finished product yield, % Drum index, % Using the coefficient, t·(m2·h)⁻¹ Comparative Example 1 73.48 53.27 1.213 Example 1 76.93 55.67 1.375 Comparative Example 2 74.55 53.31 1.221 Example 2 78.12 56.21 1.406 Comparative Example 3 77.21 53.41 1.237 Example 3 81.33 56.84 1.472

[0060] Table 4

[0061] name TFe stability FeO stability R0*Stability Comparative Example 1 91.25 63.88 84.35 Example 1 95.78 65.81 90.72 Comparative Example 2 92.51 64.82 84.72 Example 2 96.65 66.88 91.48 Comparative Example 3 93.36 65.26 85.95 Example 3 97.27 67.93 92.16

[0062] In Table 4, R0 represents the basicity of sintered ore, R0 = ω(CaO) / ω(SiO2).

[0063] As shown in Table 2 above, after the implementation of this invention, the proportion of particles larger than 8 mm in the sintered mixture is significantly reduced (mainly due to the elimination of ultra-large particles, which significantly reduces the proportion of particles larger than 8 mm), the proportion of particles smaller than 1 mm is reduced, the proportion of intermediate particles is significantly increased, the proportion of particles larger than 3 mm is increased, the proportion of particles in the 3-5 mm range is significantly increased, the overall particle size is larger, the particle size uniformity is improved, and the air permeability index (JPU) of the mixture is significantly improved.

[0064] As shown in Table 3 above, after the implementation of this invention, the yield of sintered ore, the drum index, and the sintering utilization coefficient have all been significantly improved, and the overall technical and economic indicators of sintering have been significantly improved.

[0065] As shown in Table 4 above, after the implementation of the present invention, the stability rates of TFe, FeO and R0 in sintered ore have all increased to varying degrees, especially the improvement in the stability rate of R0.

[0066] In summary, after implementing this invention, ultra-large particles in the sintering mixture disappear, the proportion of particles larger than 8mm is significantly reduced, the proportion of particles smaller than 1mm is reduced, the proportion of intermediate-sized particles in the mixture increases significantly, the proportion of particles larger than 3mm increases somewhat, and the proportion of particles between 3-5mm increases significantly. Overall, the particle size increases, and particle size uniformity improves. The permeability index (JPU) of the mixture is significantly improved. The yield of sintered ore, drum index, and sintering utilization coefficient all show significant improvements, resulting in a marked improvement in overall sintering technical and economic indicators. The stability rates of TFe, FeO, and R0 in sintered ore all increase to varying degrees, with the improvement in R0 stability being particularly significant. Overall, this invention has a significant effect on enhancing granulation of sintering mixtures and improving the quality indicators of sintered ore.

[0067] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0068] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method of prewetting sintering material using pipe concentrate, characterized by, It comprises the following steps: Step one, iron ore concentrate, sintered return ore, blast furnace return ore, dust and gas ash are added into a stirrer to be stirred to obtain premixed uniform material; the moisture content of the premixed uniform material is 5%-7%; the moisture content of the iron ore concentrate is 10%-15%; the iron ore concentrate is pipeline concentrate; the moisture content of the sintered return ore is 0%; the moisture content of the blast furnace return ore is 0%; the moisture content of the dust is 0%; the moisture content of the gas ash is 3%-4%; the mass ratio of the iron ore concentrate, sintered return ore, blast furnace return ore, dust and gas ash is (30-50):(20-30):(20-30):(0-2):(0-4) Step two, the premixed uniform material and ingredients are mixed once and granulated twice to obtain mixed material, and the mixed material is sintered; the ingredients include Australian ore, undersize material, coke powder, 58-country high, limestone and active ash.

2. The method of using pipe concentrate prewetted sintered material according to claim 1, characterized in that, In step two, the first mixing time is 5 min, and the second mixing and granulating time is 5 min.

3. The method of using pipe concentrate prewetted sintered material according to claim 1, characterized in that, In step two, the method for sintering the mixed material is that the mixed material is distributed on a sintering trolley, 3 kg of bottom material is laid, the particle size of the bottom material is 10-16 mm, the material layer thickness is 750 mm, the ignition temperature is controlled at 1050℃, the ignition time is 2 min, the ignition negative pressure is 6 kPa, and the sintering negative pressure is 12 kPa.

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