Method for improving sintered ore quality in FMG ultra-fine powder sintering process

Abstract

The invention discloses a method for improving the quality of sintered ore in the FMG ultra-fine powder sintering process. The method comprises the steps that S1, sintering burdening is conducted, specifically, mixed ore is prepared from 20%-40% of FMG ultra-fine powder, 5%-20% of fine-grain magnet fine powder, 15%-30% of Brazil powder, 1%-3% of oxidized iron scale, 5%-15% of PB powder, 5%-15% of Mecanum powder, 5%-15% of Newman powder, 15%-20% of return ore and the balance recycled fly ash and lump ore undersize powder; s2, the sintering distribution thickness is 900-1000 mm, the surface layer materials are pressed after distribution, and the rolling reduction of the materials on the edge of the trolley is larger than that of the materials in the center of the trolley; s3, the sintering ignition temperature ranges from 1000 DEG C to 1050 DEG C; s4, gas fuel is injected to the surface layer material of the trolley after sintering ignition, and the gas fuel injection amount of the edge material is higher than that of the center material; and S5, the sintering end point is controlled at the penultimate air bellow or the first air bellow. By the adoption of the control method, when FMG ultra-fine powder is used for sintering, the quality of the sintered ore can be effectively improved, the drum index of the sintered ore can reach 78% or above, the low-temperature reduction degradation index RDI + 3.15 is larger than or equal to 68%, the index requirement of a blast furnace for the sintered ore is met, and meanwhile sintering solid fuel consumption is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of sintering, and in particular relates to a method for improving the quality of sintered ore during the sintering process of FMG super special powder. Background Art

[0002] Sintered ore is one of the main raw materials for blast furnaces. The proportion of sintered ore in the blast furnace charge of domestic steel enterprises usually reaches more than 70-80%. The cost and quality of sintered ore directly affect the cost and production smoothness of the blast furnace.

[0003] FMG super-special powder is a kind of ore with high cost performance in recent years. However, due to its high burning loss, high crystal water, and high shrinkage after sintering, it will cause the strength of sintered ore to decrease and fuel consumption to increase after sintering, which will restrict the quality and cost of sintered ore and molten iron. The proportion of sintered ore in the blast furnace of the applicant is about 80%. In order to reduce the production cost of sintered ore and molten iron, it is decided to increase the proportion of FMG super-special powder in sintering. How to improve the quality of sintered ore during the sintering process of FMG super-special powder is the primary issue.

[0004] Invention patent content

[0005] In view of the problems existing in the prior art, the present invention provides a method for improving the quality of sintered ore during the sintering process of FMG super special powder, which can effectively improve the quality of sintered ore, reduce sintering fuel consumption, and meet the index requirements of blast furnace for sintered ore.

[0006] The present invention is achieved by a method for improving the quality of sintered ore in the sintering process of FMG super-special powder, characterized in that the composition of the finished sintered ore is controlled as follows: the Al2O3 content of the sintered ore is ≤2.3%, the MgO / Al2O3 of the sintered ore is 1.00-1.10, the Al2O3 / SiO2 of the sintered ore is ≤0.4, the binary basicity of the sintered ore CaO / SiO2 is ≥1.87, and the FeO content of the sintered ore is 9.0-9.5%; comprising the following steps:

[0007] S1. Sintering ingredients: The mixed ore is composed of 20-40% FMG super powder, 5-20% fine magnetite powder, 15-30% Brazilian powder, 1-3% iron oxide scale, 5-15% PB powder, Mike powder and Newman powder, 15-20% return ore, and the rest is recycled dust and lump ore undersize powder, with a total ratio of 100%; the sintering flux is limestone, quicklime and magnesite, with a ratio of 2-10%; the sintering fuel is coke powder and / or coal powder, with a ratio of 2-6%;

[0008] S2. The thickness of the sintering material is 900-1000mm. After the material is laid, the surface material is pressed, and the pressing amount of the material at the edge of the trolley is greater than the pressing amount of the material in the center of the trolley;

[0009] S3, sintering ignition temperature is 1000~1050℃;

[0010] S4. After sintering and ignition, gas fuel is sprayed on the surface material of the trolley, and the gas fuel spraying amount of the edge material is higher than the gas fuel spraying amount of the center material;

[0011] S5. The sintering endpoint is controlled at the second to last bellows or the first bellows; the sintering endpoint temperature is 380-480°C.

[0012] Further preferably, the proportion of -200 mesh in the particle size composition of the fine-grained magnetite concentrate is ≥90%, the TFe content in the composition is ≥69%, and the FeO content is ≥28%.

[0013] Preferably, the gas fuel injected into the surface material is coke oven gas, and the injection volume is 0-1500m 3 / h.

[0014] The beneficial effects of the present invention: After adopting the present invention, by optimizing the batching structure and using fine-grained magnetite powder and Brazilian powder to mix with FMG super-special powder, the assimilation of the material and the liquid phase fluidity can be improved, the generation of large-pore thin-walled structures during the sintering of FMG super-special powder can be reduced, and the strength of the sintered ore can be improved; by controlling the component content of the sintered ore, the generation of high-quality liquid phase calcium ferrite (especially needle-shaped calcium ferrite) can be promoted, the bonding phase strength can be improved, and thus the strength of the sintered ore can be improved; by controlling the cloth thickness, ignition temperature, terminal temperature, spraying gas fuel on the surface material, and differentially controlling the pressure and heat input of the edge material and the center material, the quality uniformity of the sintered ore along the width direction and longitudinal direction of the sintering machine trolley can be improved, and at the same time, the use of gas fuel to replace part of the solid fuel can reduce solid fuel consumption and fuel costs. Through the above operations, the quality of the sintered ore can be effectively improved when using FMG super-special powder for sintering, the drum index of the sintered ore reaches more than 78%, and the low-temperature reduction pulverization index RDI +3.15 ≥68%, which meets the blast furnace's demand for sintered ore and reduces sintering solid fuel consumption and fuel costs. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments.

[0017] The invention discloses a method for improving the quality of sintered ore in the sintering process of FMG super-special powder. The composition of the finished sintered ore is controlled as follows: the Al2O3 content of the sintered ore is ≤2.3%, the MgO / Al2O3 of the sintered ore is 1.00-1.10, the Al2O3 / SiO2 of the sintered ore is ≤0.4, the binary basicity CaO / SiO2 of the sintered ore is ≥1.87, and the FeO content of the sintered ore is 9.0-9.5%. The method comprises the following steps:

[0018] 1. Sintering ingredients: The mixed ore is composed of 20-40% FMG super powder, 5-20% fine magnetite powder, 15-30% Brazilian powder, 1-3% iron oxide scale, 5-15% PB powder, Mike powder, and Newman powder, 15-20% return ore, and the rest is recycled dust and lump ore underscreen powder, with a total ratio of 100%. The sintering flux is limestone, quicklime, and magnesite, with a ratio of 2-10%. The sintering fuel is coke powder and / or coal powder, with a ratio of 2-6%.

[0019] 2. The thickness of the sintering cloth is 900-1000mm. After the cloth is laid, the surface material is pressed, and the amount of material pressed down at the edge of the trolley is greater than the amount of material pressed down at the center of the trolley.

[0020] 3. The sintering ignition temperature is 1000-1050℃.

[0021] 4. After sintering and ignition, gas fuel is sprayed on the surface material of the trolley, and the gas fuel spraying amount of the edge material is higher than that of the center material.

[0022] 5. The sintering end point is controlled at the second to last bellows or the first bellows; the sintering end point temperature is 380-480℃.

[0023] Furthermore, the proportion of -200 mesh in the particle size composition of the fine-grained magnetite concentrate is ≥90%, the TFe content in the composition is ≥69%, and the FeO content is ≥28%.

[0024] Furthermore, the gas fuel injected into the surface material is preferably coke oven gas, and the injection volume is 0 to 1500m 3 / h.

[0025] Example 1: A method for improving the quality of sintered ore during the sintering process of FMG super special powder: comprising the following steps:

[0026] 1. Sintering ingredients: The mixed ore is composed of 30% FMG super powder, 10% fine magnetite powder, 14% Brazilian coarse powder, 5% Brazilian card powder, 3% iron oxide, 10% PB powder, 5% Mike powder, 19% return ore, 1% recycled dust, and 3% lump ore undersize powder. The fine magnetite powder has a particle size composition of -200 mesh of 95%, TFe content of 69.70%, and FeO content of 29.88%. The sintering flux is 4.7% limestone, 5.2% quicklime, and 3.1% magnesite. The fuel is coke powder, with a ratio of 4.3%.

[0027] 2. The thickness of the sintering cloth is 950mm. After the cloth is laid, the surface material is pressed. The pressing amount of the material at the edge of the trolley is greater than the pressing amount of the material in the center of the trolley.

[0028] 3. The sintering ignition temperature is 1050℃.

[0029] 4. After sintering and ignition, spray coke oven gas on the surface of the trolley with a spray volume of 200m 3 / h, and at the same time control the coke oven gas injection amount of the edge material to be higher than the coke oven gas injection amount of the center material.

[0030] 5. Control the sintering end point at the penultimate wind box, and the end point temperature is 420℃.

[0031] After the above steps, the sintered ore with the following technical indicators can be obtained:

[0032] A. Composition of finished sintered ore

[0033] <![CDATA[Al2O3(%)]]> MgO(%) <![CDATA[SiO2(%)]]> FeO(%) <![CDATA[CaO / SiO2(R)]]> <![CDATA[Al2O3 / SiO2]]> <![CDATA[MgO / Al2O3]]> 2.09 2.1 5.4 9.5 1.9 0.387 1.00

[0034] B. Sinter quality indicators and metallurgical properties

[0035] Drum index (%) Screening index (%) <10mm ratio (%) <![CDATA[RDI +3.15 (%)]]> 78.67 1.6 22.6 69.1

[0036] Example 2: A method for improving the quality of sintered ore during the sintering process of FMG super special powder: comprising the following steps:

[0037] 1. Sintering ingredients: The mixed ore is composed of 35% FMG super powder, 15% fine magnetite powder, 18% Brazilian coarse powder, 6% Brazilian card powder, 2% iron oxide, 5% PB powder, 18% return ore, and 1% recycled dust. The fine magnetite powder has a particle size of -200 mesh of 96%, a TFe content of 69.20%, and a FeO content of 29.50%. The sintering flux is 4.2% limestone, 6.0% quicklime, and 2.85% magnesite. The fuel is pulverized coal, with a ratio of 4.1%.

[0038] 2. The thickness of the sintering material is 980mm. After the material is laid, the surface material is pressed, and the pressing amount of the material at the edge of the control trolley is greater than the pressing amount of the material in the center of the trolley.

[0039] 3. The sintering ignition temperature is 1030℃.

[0040] 4. After sintering and ignition, coke oven gas is sprayed on the surface material of the trolley, with a spray volume of 800m 3 / h, and at the same time control the coke oven gas injection amount of the edge material to be higher than the coke oven gas injection amount of the center material.

[0041] 5. Control the sintering end point at the second to last wind box, and the end point temperature is 440℃.

[0042] After the above steps, the sintered ore with the following technical indicators can be obtained:

[0043] A. Composition of finished sintered ore

[0044] <![CDATA[Al2O3(%)]]> MgO(%) <![CDATA[SiO2(%)]]> FeO(%) <![CDATA[CaO / SiO2(R)]]> <![CDATA[Al2O3 / SiO2]]> <![CDATA[MgO / Al2O3]]> 1.98 2.00 5.44 9.30 1.95 0.36 1.01

[0045] B. Sinter quality indicators and metallurgical properties

[0046] Drum index (%) Screening index (%) <10mm ratio (%) <![CDATA[RDI +3.15 (%)]]> 79.33 1.5 27.8 72.3

[0047] Example 3: A method for improving the quality of sintered ore during the sintering process of FMG super special powder: comprising the following steps:

[0048] 1. Sintering ingredients: The mixed ore is composed of 20% FMG super powder, 5% fine magnetite powder, 12% Brazilian coarse powder, 14% Brazilian card powder, 3% iron oxide, 10% Mike powder, 14% Newman powder, 18% return ore, 2% recycled dust, and 2% lump ore undersize powder. Among them, the proportion of -200 mesh in the particle size composition of fine magnetite powder is 97.5%, the TFe content is 69.58%, and the FeO content is 29.00%. The sintering flux is 4.5% limestone, 5.7% quicklime, and 3.4% magnesite. The fuel is coke powder and coal powder in a ratio of 1:1, with a ratio of 1.95% respectively, and the total fuel ratio is 3.9%.

[0049] 2. The thickness of the sintering material is 960mm. After the material is laid, the surface material is pressed, and the pressing amount of the material at the edge of the control trolley is greater than the pressing amount of the material in the center of the trolley.

[0050] 3. The sintering ignition temperature is 1045℃.

[0051] 4. After sintering and ignition, coke oven gas is sprayed on the surface material of the trolley, with a spray volume of 1200m 3 / h, and at the same time control the coke oven gas injection amount of the edge material to be higher than the coke oven gas injection amount of the center material.

[0052] 5. Control the sintering end point at the penultimate wind box, and the end point temperature is 400℃.

[0053] After the above steps, the sintered ore with the following technical indicators can be obtained:

[0054] A. Composition of finished sintered ore

[0055] <![CDATA[Al2O3(%)]]> MgO(%) <![CDATA[SiO2(%)]]> FeO(%) <![CDATA[CaO / SiO2(R)]]> <![CDATA[Al2O3 / SiO2]]> <![CDATA[MgO / Al2O3]]> 2.08 2.20 5.21 9.45 2.05 0.40 1.06

[0056] B. Sinter quality indicators and metallurgical properties

[0057] Drum index (%) Screening index (%) <10mm ratio (%) <![CDATA[RDI +3.15 (%)]]> 78.33 1.8 30.5 68.6

[0058] Example 4: A method for improving the quality of sintered ore during the sintering process of FMG super special powder: comprising the following steps:

[0059] 1. Sintering ingredients: The mixed ore is composed of 40% FMG super powder, 15% fine magnetite powder, 8% Brazilian coarse powder, 13% Brazilian card powder, 1% iron oxide, 5% PB powder, and 18% return ore. Among them, the particle size composition of fine magnetite powder is -200 mesh, the content of TFe is 69.11%, and the content of FeO is 29.10%. The sintering flux is 4.5% limestone, 5.9% quicklime, and 3.2% magnesite. The fuel is coke powder and coal powder in a ratio of 1:1, with a total ratio of 4.0%.

[0060] 2. The thickness of the sintering material is 980mm. After the material is laid, the surface material is pressed, and the pressing amount of the material at the edge of the control trolley is greater than the pressing amount of the material in the center of the trolley.

[0061] 3. The sintering ignition temperature is 1050℃.

[0062] 4. After sintering and ignition, coke oven gas is sprayed on the surface material of the trolley, with a spray volume of 950m 3 / h, and at the same time control the coke oven gas injection amount of the edge material to be higher than the coke oven gas injection amount of the center material.

[0063] 5. Control the sintering end point at the second to last wind box, and the end point temperature is 390℃.

[0064] After the above steps, the sintered ore with the following technical indicators can be obtained:

[0065] A. Composition of finished sintered ore

[0066] <![CDATA[Al2O3(%)]]> MgO(%) <![CDATA[SiO2(%)]]> FeO(%) <![CDATA[CaO / SiO2(R)]]> <![CDATA[Al2O3 / SiO2]]> <![CDATA[MgO / Al2O3]]> 2.04 2.10 5.20 9.20 2.05 0.39 1.03

[0067] B. Sinter quality indicators and metallurgical properties

[0068] Drum index (%) Screening index (%) <10mm ratio (%) <![CDATA[RDI +3.15 (%)]]> 79 1.6 29.9 70.1

[0069] It can be seen from the above examples that when FMG super powder is added during the sintering process, through the implementation of this method, the drum index of the sintered ore can reach more than 78%, the screening index is less than 3%, the proportion of sintered ore particle size <10mm can be less than 33%, and the low temperature reduction powder index RDI can reach 100%. +3.15 Reaching more than 68%, it can meet the material needs of blast furnaces. At the same time, by injecting coke oven gas, it replaces part of the solid fuel, which also reduces solid fuel consumption and fuel costs.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the patent protection scope of the present invention.

Claims

1. A method for improving the quality of sintered ore during the sintering process of FMG super special powder, characterized in that: The composition of the finished sintered ore is controlled as follows: the Al2O3 content of the sintered ore is ≤2.3%, the MgO / Al2O3 of the sintered ore is 1.00-1.10, the Al2O3 / SiO2 of the sintered ore is ≤0.4, the binary basicity of the sintered ore CaO / SiO2 is ≥1.87, and the FeO content of the sintered ore is 9.0-9.5%; the following steps are included: S1. Sintering ingredients: The mixed ore is composed of 20-40% FMG super powder, 5-20% fine magnetite powder, 15-30% Brazilian powder, 1-3% iron oxide scale, 5-15% PB powder, Mike powder and Newman powder, 15-20% return ore, and the rest is recycled dust and lump ore undersize powder, with a total ratio of 100%; the sintering flux is limestone, quicklime and magnesite, with a ratio of 2-10%; the sintering fuel is coke powder and / or coal powder, with a ratio of 2-6%; S2. The thickness of the sintering material is 900-1000mm. After the material is laid, the surface material is pressed, and the pressing amount of the material at the edge of the trolley is greater than the pressing amount of the material in the center of the trolley; S3, sintering ignition temperature is 1000~1050℃; S4. After sintering and ignition, gas fuel is sprayed on the surface material of the trolley, and the gas fuel spraying amount of the edge material is higher than the gas fuel spraying amount of the center material; S5. The sintering endpoint is controlled at the second to last bellows or the first bellows; the sintering endpoint temperature is 380-480°C.

2. The method for improving the quality of sintered ore during the sintering process of FMG super special powder according to claim 1, characterized in that: The proportion of -200 mesh in the particle size composition of the fine-grained magnetite concentrate is ≥90%, the TFe content in the composition is ≥69%, and the FeO content is ≥28%.

3. The method for improving the quality of sintered ore during the sintering process of FMG super special powder according to claim 1, characterized in that: The gas fuel injected into the surface material is coke oven gas, and the injection volume is 0~1500m 3 / h.