Experimental method for improving strength of sinter drum by adjusting proportion of calcium flux in sintering

Abstract

The invention discloses an experimental method for improving the drum strength of sintered ore by adjusting the proportion of a calcium flux in sintering, which comprises the following steps: mixing 37% of self-produced concentrate, 48% of iron ore powder A, 7% of iron ore powder B, 8% of iron ore C, 0-9.8% of limestone, 2-3% of light-burned dolomite, 0.1-0.6% of serpentine, 0-7% of quick lime and 4.15% of coke powder in percentage by mass; adding water into the raw materials, mixing and granulating to obtain a mixture; distributing, igniting and sintering the mixture to obtain sintered ore; the drum strength of the sintered ore is further improved by adjusting the proportion of calcium flux quicklime and limestone at the same time, and the purpose of the invention is to improve the drum strength of the sintered ore and improve the quality of the sintered ore by adjusting the proportion of the calcium flux quicklime, limestone and the like in the sintering process.

Description

Technical Field

[0001] The invention belongs to the technical field of sintering, and in particular relates to an experimental method for improving the drum strength of sintered ore by adjusting the proportion of calcium flux in sintering. Background Art

[0002] Sintering is the process of mixing various iron-containing powdered raw materials with appropriate amount of fuel and flux, adding appropriate amount of water, mixing and pelletizing, and then making a series of physical and chemical changes in the materials on the sintering equipment to bond the ore powder particles into blocks. Sintered ore is currently the most important raw material for blast furnaces. The quality of sintered ore directly affects the changes in blast furnace indicators. The indicators for measuring the quality of sintered ore include particle size composition, drum strength, metallurgical properties, etc. Among them, drum strength directly reflects the hardness and wear resistance of sintered ore. It is an important indicator for evaluating the quality of sintered ore, which is directly related to the quality of the product and plays a vital role in the stable and smooth operation of the blast furnace.

[0003] The calcium flux used in the sintering process is mainly quicklime, slaked lime and limestone. The calcium flux used by Baosteel is quicklime and limestone. Under the condition that the raw materials and sintering parameters are consistent, the calcium fluxes such as quicklime and limestone in sintering have different sintering ratios, which have a certain influence on the strength of the sintered ore. The present invention improves the drum strength of the sintered ore and the quality of the sintered ore by adjusting the ratio of quicklime and limestone in sintering, thereby laying a raw material foundation for the stable and smooth operation of the blast furnace. Summary of the invention

[0004] The purpose of the present invention is to provide an experimental method for improving the drum strength of sintered ore by adjusting the ratio of calcium flux in sintering, and to improve the drum strength of sintered ore and the quality of sintered ore by adjusting the ratio of calcium flux such as quicklime and limestone in the sintering process.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The invention discloses an experimental method for improving the drum strength of sintered ore by adjusting the proportion of calcium flux in sintering. According to the mass percentage, 37% of self-produced concentrate, 48% of iron ore powder A, 7% of iron ore powder B, 8% of iron ore C, 0% to 9.8% of limestone, 2% to 3% of light-burned dolomite, 0.1% to 0.6% of serpentine, 0% to 7% of quicklime and 4.15% of coke powder are added with water and granulated to obtain a mixture; the mixture is distributed, ignited and sintered to obtain a sintered ore;

[0007] in:

[0008] The components of the self-produced concentrate include, by mass percentage: 64.5-66.5% TFe, 25-29% FeO, 0.5-1.5% CaO, 1-3% SiO2, 0.5-1.5% MgO, 0.05-0.2% Na2O, 0.1-0.4% F, 0.5-1.5% S, 0.05-0.2% K2O, with a particle size of -200 mesh and a content of >90%;

[0009] The components of the iron ore powder A include, by mass percentage, 59-62% TFe, <1% FeO, <0.2% CaO, 3-6% SiO2, <0.1% MgO, <0.1% S, and the components of Ig include, by mass percentage, 2-7%, and the content of particle size -1mm <45%;

[0010] The components of the iron ore powder B include, by mass percentage, 57-61% TFe, <1% FeO, <0.2% CaO, 0-6% SiO2, <0.2% MgO, <0.2% S, and the components of Ig include, by mass percentage, 2-7%, and a particle size of -1 mm and a content of <30%;

[0011] The composition of the iron ore powder C includes, by mass percentage, 55-60% TFe, <5% FeO, 1-3% CaO, 8-16% SiO2, <2% MgO, <0.3% Na2O, <2% S, <0.2% K2O, and the content of -1mm particle size is <40%;

[0012] By adjusting the ratio of calcium flux quicklime in sintering: 0-7%, the adjustment step is 1%, and the basicity of the sintered ore is controlled at 2.0±0.1. The ratio of calcium flux limestone in sintering is adjusted to: 9.8%, 8.5%, 7.1%, 5.0%, 4.3%, 2.9%, 1.3%, 0% corresponding to the ratio of quicklime. By adjusting the ratio of calcium flux quicklime and limestone at the same time, the drum strength of the sintered ore is further improved.

[0013] Furthermore, the components of the limestone include, by mass percentage: 45-55% CaO, 4-6% SiO2, <5% MgO, and the components of Ig include, by mass percentage: <50%, and the particle size is -3mm and the content is >90%.

[0014] Furthermore, the components of the quicklime include, by mass percentage: >75% CaO, 4-6% SiO2, <5% MgO, and the components of Ig include, by mass percentage: <20%, and the particle size is -3mm and the content is >90%.

[0015] Furthermore, the light-burned dolomite and serpentine in the mixture are used as fluxes in sintering to adjust the SiO2 and MgO contents of the sintered ore. The SiO2 content is controlled to be 5.2±0.1, and the MgO content is controlled to be 2.0±0.1 in terms of mass percentage.

[0016] Furthermore, the mass percentage of water in the mixture is 6.5% to 7.5%.

[0017] Furthermore, the mixed material is granulated in a mixing device, and the process control time is 3-5 minutes.

[0018] Furthermore, the pelletized mixed material is subjected to a distributing operation.

[0019] Furthermore, the mixed material arranged in the sintering device was ignited, the ignition temperature was controlled at 1000° C., the ignition negative pressure was controlled at 6 KPa, and the ignition time was 2 min.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are:

[0021] The invention further improves the drum strength of the sintered ore and improves the quality of the sintered ore by simultaneously adjusting the proportion of quicklime and limestone, which are calcium fluxes in sintering. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with embodiments:

[0023] In this embodiment, under the same iron material configuration structure, by adjusting the ratio of calcium flux quicklime and limestone during sintering, a sintering cup test is carried out to measure the drum strength under different ratios of calcium flux quicklime and limestone. The specific chemical composition of the raw materials used in the test and the sintering raw material configuration scheme are shown in Tables 1 and 2:

[0024] Table 1 Chemical analysis results of sintering test raw materials

[0025]

[0026] Table 2 Sintering test ratio scheme

[0027]

[0028] As shown in Table 2, under the condition that the iron ore configuration remains unchanged in all sintering tests, the sintering basicity is controlled to be 2.0±0.1, and the proportion of calcium flux quicklime is adjusted from 0% to 7%, with a step size of 1% each time. The corresponding proportions of calcium flux limestone are adjusted to: 9.8%, 8.5%, 7.1%, 5.0%, 4.3%, 2.9%, 1.3%, and 0%.

[0029] The ratio of light-burned dolomite and serpentine in the mixture is calculated according to the sintering batching formula, the SiO2 component is controlled at 5.2±0.1 in mass percentage, and the MgO component is controlled at 2.0±0.1 in mass percentage.

[0030] The raw materials are mixed according to the raw material ratio shown in Table 2. The raw materials are mixed with water in the primary mixer, and the moisture content is controlled to be 7.5-8.5%; then the raw materials are granulated in the secondary mixer, and the granulation time is 3 minutes; the granulated mixture is evenly distributed to the sintering device through the distributor, and the material layer thickness is 700mm. It is ignited by the sintering igniter, and the ignition fuel is natural gas. The ignition time is 120s. At the same time, the bottom of the sintering device begins to evacuate, and a certain negative pressure is formed under the grate. The ignition negative pressure is 6kPa. After ignition, the air is evacuated from top to bottom through the sintering material layer. The sintering evacuation negative pressure is 10kPa. After ignition, the burning zone on the surface of the material layer gradually moves to the lower material layer as the upper fuel is burned. When the burning zone reaches the grate, the sintering process ends and sintered ore is obtained. The quality performance indicators of sintered ore are shown in Table 3.

[0031] Table 3 Changes in the drum strength of sintered ore with calcium flux adjustment

[0032]

[0033] It can be seen from Table 3 that when the ratio of quicklime, a calcium flux, is increased from 0 to 7% during sintering, the drum strength of the sintered ore shows a trend of first decreasing and then increasing. When the ratio of quicklime is 6% and the ratio of limestone is 1.3%, the drum strength of the sintered ore reaches the highest value, and when the ratio of quicklime is 4% and the ratio of limestone is 4.3%, the drum strength reaches the lowest value. Therefore, it is shown that under the condition that the configuration of sintering iron materials remains unchanged, by adjusting the ratio of quicklime and limestone, the drum strength of the sintered ore can be improved and the quality of the sintered ore can be improved.

[0034] The invention increases the drum strength of the sintered ore by simultaneously adjusting the proportion of quicklime and limestone, a calcium flux in sintering, thereby improving the quality of the sintered ore, increasing the yield rate and reducing the sintering cost.

[0035] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An experimental method for improving the drum strength of sintered ore by adjusting the ratio of calcium flux during sintering, characterized in that: According to the percentage by mass, the following raw materials are added with water, mixed and granulated to obtain a mixed material: 37% of self-produced concentrate, 48% of iron ore powder A, 7% of iron ore powder B, 8% of iron ore C, 0% to 9.8% of limestone, 2% to 3% of light-burned dolomite, 0.1% to 0.6% of serpentine, 0% to 7% of quicklime, and 4.15% of coke powder; The mixed material is distributed, ignited, and sintered to obtain sintered ore; in: The components of the self-produced concentrate include, by mass percentage, 64.5-66.5% TFe, 25-29% FeO, 0.5-1.5% CaO, 1-3% SiO2, 0.5-1.5% MgO, 0.05-0.2% Na2O, 0.1-0.4% F, 0.5-1.5% S, 0.05-0.2% K2O, with a particle size of -200 mesh and a content of >90%; The components of the iron ore powder A include, by mass percentage, 59-62% TFe, <1% FeO, <0.2% CaO, 3-6% SiO2, <0.1% MgO, <0.1% S, and the components of Ig include, by mass percentage, 2-7%, and the content of particle size -1mm <45%; The components of the iron ore powder B include, by mass percentage, 57-61% TFe, <1% FeO, <0.2% CaO, 0-6% SiO2, <0.2% MgO, <0.2% S, and the components of Ig include, by mass percentage, 2-7%, and a particle size of -1 mm and a content of <30%; The composition of the iron ore powder C includes, by mass percentage, 55-60% TFe, <5% FeO, 1-3% CaO, 8-16% SiO2, <2% MgO, <0.3% Na2O, <2% S, <0.2% K2O, and the content of -1mm particle size is <40%; By adjusting the ratio of calcium flux quicklime in sintering: 0-7%, the adjustment step is 1%, and the basicity of the sintered ore is controlled at 2.0±0.

1. The ratio of calcium flux limestone in sintering is adjusted to: 9.8%, 8.5%, 7.1%, 5.0%, 4.3%, 2.9%, 1.3%, 0% corresponding to the ratio of quicklime. By adjusting the ratio of calcium flux quicklime and limestone at the same time, the drum strength of the sintered ore is further improved.

2. The experimental method for improving the drum strength of sintered ore by adjusting the calcium flux ratio during sintering according to claim 1, characterized in that: The components of the limestone include, by mass percentage, 45-55% CaO, 4-6% SiO2, <5% MgO, and the components of Ig include, by mass percentage, <50%, and the particle size is -3mm and the content is >90%.

3. The experimental method for improving the drum strength of sintered ore by adjusting the calcium flux ratio during sintering according to claim 1, characterized in that: The components of the quicklime include, by mass percentage: >75% CaO, 4-6% SiO2, <5% MgO, and the components of Ig include, by mass percentage: <20%, and the particle size is -3mm with a content of >90%.

4. The experimental method for improving the drum strength of sintered ore by adjusting the calcium flux ratio during sintering according to claim 1, characterized in that: The light-burned dolomite and serpentine in the mixture are used as fluxes in sintering to adjust the SiO2 and MgO contents of the sintered ore. The SiO2 content is controlled to be 5.2±0.1, and the MgO content is controlled to be 2.0±0.1 in terms of mass percentage.

5. The experimental method for improving the drum strength of sintered ore by adjusting the calcium flux ratio during sintering according to claim 1, characterized in that: The mass percentage of water in the mixture is 6.5% to 7.5%.

6. The experimental method for improving the drum strength of sintered ore by adjusting the calcium flux ratio during sintering according to claim 1, characterized in that: The mixed material is granulated in a mixing device, and the process control time is 3-5 minutes.

7. The experimental method for improving the drum strength of sintered ore by adjusting the calcium flux ratio during sintering according to claim 1, characterized in that: The granulated mixture is then placed in the distribution operation.

8. The experimental method for improving the drum strength of sintered ore by adjusting the calcium flux ratio during sintering according to claim 1, characterized in that: The mixed material arranged in the sintering device is ignited, the ignition temperature is controlled at 1000°C, the ignition negative pressure is controlled at 6KPa, and the ignition time is 2min.

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