Method for improving air permeability of sintered material layer

Abstract

The invention belongs to the technical field of sintering processes in the metallurgical industry, and particularly relates to a method for improving the air permeability of a sintered material layer, which comprises the following steps: before a sintering machine distributes materials, bedding materials are firstly laid; sintered ore sintered by the sintering machine enters the circular cooler to be cooled, and steam released in the process is introduced into the secondary mixing device and the mixing trough so as to increase the temperature value of sintered materials to a set value. The method has the beneficial effects that the quick lime with the activity being greater than 300mL and the CaO content being 85-91% is added into the batching bin; hot water is distributed to a first mixing device, so that the content of the hot water in a sintered material layer is 7.9-9.3%; introducing steam into a secondary mixing device and a mixing trough so as to increase the material temperature to 88-96 DEG C; sintering ore with the particle size of 12-20 mm is screened out to serve as a grate-layer material, and the thickness is 30-40 mm; and the gap between the grate bars of the sintering machine is 5-7mm, and a plurality of parameters in the sintering process are adjusted, so that the air permeability of a sintered material layer is improved, the sintering speed is increased by about 5%, and a better economic effect is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of sintering process in metallurgical industry, and in particular relates to a method for improving the air permeability of a sintering material layer. Background Art

[0002] In the sintering production process, the permeability of the mixture is the most core control parameter in the sintering process, which directly affects the output and quality of the sintered ore. If the permeability index is too high, the vertical sintering speed is fast, the residence time in the high temperature zone of the sintering process is short, and the amount of liquid phase formed is small, resulting in a decrease in the strength of the sintered ore. If the permeability index is too low, the vertical sintering speed is slow and the sintered ore is easy to overburn, reducing the output of the sintered ore. Therefore, the appropriate permeability of the sintering mixture is the premise for stabilizing the sintering end position and ensuring the output and quality of the sintered ore.

[0003] At present, the typical method to improve the air permeability of the sintering material layer is to strengthen the granulation or add various additives to the sintering mixture. In essence, these methods are to make certain adjustments to the sintering materials, thereby changing the strength of the sintered ore. The existing sintering machines are mostly composed of a circular track composed of head and tail star wheels. The rotation of the star wheels drives the sintering machine trolley to run straight on the fixed track. As the sintering material layer continues to increase, the air permeability of the sintering material layer during the sintering process is very poor, which will greatly affect the product quality of the sintered ore. Summary of the invention

[0004] In order to solve the above-mentioned technical problems, the present invention provides a method for improving the air permeability of a sintering material layer, thereby solving the technical problem that the existing sintering material has poor air permeability during the sintering process, thereby affecting the sintering quality.

[0005] The technical solution adopted in the embodiment of the present invention is: a method for improving the air permeability of a sintered material layer, characterized in that it comprises the following steps:

[0006] The sintering machine lays the base material before spreading the material;

[0007] The sintered ore after sintering in the sintering machine enters the ring cooler for cooling. The steam released in this process is introduced into the secondary mixing device and the mixing tank to increase the material temperature of the sintering material to the set value.

[0008] Furthermore, the base material comes from the sintered ore after screening.

[0009] Furthermore, the sintered ore is cooled by the ring cooler and then enters a screening device for screening, and the sintered ore meeting the particle size requirement is used as the base material.

[0010] Furthermore, the paving material has a particle size of 12 to 20 mm and a thickness of 30 to 40 mm.

[0011] Furthermore, the set value is 88-96°C.

[0012] Furthermore, the sintering material in the batching bin passes through the first mixing device, the second mixing device and the strong mixing device in sequence and then enters the mixing tank.

[0013] Furthermore, heating water is added to the first mixing device so that the hot water content in the sintering material layer is 7.9-9.3%.

[0014] Furthermore, after laying the base material, the material is laid so that the thickness of the entire material layer is controlled within the range of 1000 mm to 1050 mm.

[0015] Furthermore, quicklime with an activity greater than 300 mL and a CaO content of 85-91% is added to the batching bin.

[0016] Furthermore, the grate bar gap of the sintering machine is 5 to 7 mm.

[0017] The advantages and positive effects of the present invention are as follows: quicklime with an activity of more than 300 mL and a CaO content of 85-91% is added to a batching bin; during the stirring process of the first mixer, hot water is added to the first mixing device to make the hot water content in the sintering material layer be 7.9-9.3%; the steam released during the cooling process of the ring cooler is introduced into the second mixing device and the mixing material tank to increase the material temperature to 88-96°C; sintered ore with a particle size of 12-20 mm is screened out for use as a base material, the thickness of the base material is 30-40 mm, and the material layer thickness is controlled to be 1000 mm-1050 mm; the grate gap of the sintering machine is 5-7 mm, and by adjusting multiple parameters in the sintering process, the sintering speed is increased by about 5% while the air permeability of the sintering material layer is improved, thereby achieving better economic effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of an embodiment provided by the present invention. DETAILED DESCRIPTION

[0019] An embodiment of the present invention provides a method for improving the air permeability of a sintering material layer, which is described below with reference to the accompanying drawings.

[0020] Reference Figure 1 As shown, a method for improving the air permeability of a sintered material layer comprises the following steps:

[0021] The sintering machine lays the base material before spreading the material;

[0022] After sintering by the sintering machine, the sintered ore enters the annular cooler for cooling. The steam released in this process is introduced into the secondary mixing device and the mixing tank to increase the material temperature of the sintered material to the set value. The suitable particle size and thickness of the base material can prevent the fine particles or sintered ore from clogging and sticking to the clearing bar, so that the air flow distribution of the sintered material is uniform. Increasing the temperature of the mixed sintered material to above the dew point temperature can significantly and effectively reduce the over-humidity phenomenon formed by the condensation of water vapor in the material layer, thereby reducing the resistance of the air flow in the over-humidified layer, improving the air permeability of the material layer, increasing the amount of air passing through the material layer to accelerate the combustion speed, reduce the thickness of the combustion zone, accelerate the cooling speed of the melt, and reduce the air flow resistance. This technical solution makes full use of the heat released during the cooling process of the annular cooler, and introduces part of the heat into the secondary mixing device for preheating, and the other part into the mixing tank for re-preheating to increase the temperature of the mixed sintered material. At the same time, the particle size and thickness of the base material are adjusted, which greatly improves the air permeability of the material layer. In addition, the steam released during the operation of the annular cooler is fully utilized to improve the rational use of energy and achieve energy conservation and emission reduction in the sintering process.

[0023] Preferably, the bottom material comes from the sieved sintered ore. When in use, before placing the sintered material on the sintering machine trolley, a layer of bottom material is first placed. The bottom material with appropriate particle size and thickness can prevent fine particles or sintered ore from clogging and sticking to the settling bars, keep the effective exhaust area of ​​the furnace tube bars unchanged, make the air flow evenly distributed, reduce the exhaust resistance, maintain good air permeability, and accelerate the sintering process. In addition, the bottom material also has the function of protecting the equipment.

[0024] Preferably, the sintered ore is cooled in a ring cooler and then enters a screening device for screening, and the sintered ore that meets the particle size requirement is used as a base material, thereby realizing the reuse of the returned ore, improving the utilization rate of the returned ore, and achieving the purpose of saving energy and cost.

[0025] Preferably, the screening device is a screen with different apertures to screen the sintered ore. It should be noted that screening the sintered ore by using multiple screens is a routine operation and choice for those skilled in the art, and its structure and specific function will not be elaborated in depth.

[0026] Preferably, the particle size of the bed material is 12-20 mm and the thickness is 30-40 mm. In this embodiment, the mesh size of the screening device is changed to match the particle size of the bed material, and the sintered ore with a particle size of 12-20 mm is screened out to form the bed material. The thickness of the bed material is 30-40 mm, which improves the air permeability of the mixture.

[0027] Preferably, the set value is 88-96°C. After preheating the sintering mixtures of different raw material particle sizes, the output of sintered ore is improved to varying degrees, and the finer the particle size, the more obvious the effect of preheating the sintering mixture. The mixed sintering material output from the drum of the sintering second mixing device is transported to the strong mixing device for stirring, which can further improve the dispersion effect of the sintering material and improve the degree of multiphase flow mixing. In this embodiment, the mixed steam above 200°C is introduced into the second mixing device and the mixing tank respectively, and the material temperature is increased to 88-96°C.

[0028] Preferably, the sintering material in the batching bin enters the mixing tank after passing through a mixing device, a second mixing device and a strong mixing device in sequence. In the present embodiment, the first mixing device and the second mixing device are respectively a first mixer and a second mixer, so as to stir the mixed sintering material. The strong mixing device is a strong mixer, and a strong mixing device is added after the first mixing device and the second mixing device. A straight-blade disc turbine propeller is provided inside the strong mixing device, which is more suitable for stirring the mixture, enhancing the mixing and pelletizing effects, thereby improving the air permeability of the mixture, and the air permeability of the mixture is improved by fully stirring the sintering material. It should be noted that the first mixer, the second mixer and the strong mixer are structures and methods of use that can be understood by those skilled in the art, and no further elaboration is made here.

[0029] Preferably, hot water is added to a mixing device so that the hot water content in the sintering material layer is 7.9-9.3%. When in use, hot water above 80°C is added to the drum of the mixing device, and the hot water and the sintering material are mixed and stirred to form a mixture. The content of hot water in the entire material layer is 7.9-9.3%. The hot water has a heat transfer effect in the material layer, which can improve the heat permeability in the sintering mixture.

[0030] Preferably, after laying the base material, the material is laid so that the thickness of the entire material layer is controlled within the range of 1000 mm to 1050 mm.

[0031] Preferably, quicklime with an activity of more than 300 mL and a CaO content of 85-91% is added to the batching bin. The higher the activity, the better the quality of the quicklime. As the amount of quicklime added increases, the permeability of the sintering material layer will continue to improve, thereby increasing the sintering ore output.

[0032] Preferably, the grate gap of the sintering machine is 5 to 7 mm. In the actual sintering production process, the grate blockage of the sintering machine mainly refers to the gradual sticking of materials on the grate bars and the insulation frame. The more materials stick, the smaller the gap between the grate bars and the insulation frame becomes, the grate bars become difficult to move, and the grate bars of the entire trolley are gradually blocked. After the small-sized mixed material is spread on the sintering machine trolley, a large amount of dust is formed in the drying zone and the over-wet zone as the sintering process proceeds. At the same time, the air is drawn through the gap between the grate bars, which aggravates the blockage. Enlarging the gap between the grate bars within a certain range can effectively improve the air permeability of the material layer.

[0033] Embodiment 1:

[0034] After the sintering material passes through the batching bin, it passes through the first mixer, the second mixer and the strong mixer in sequence and then enters the mixing tank. During the stirring process of the first mixer, hot water is added to the first mixing device to make the hot water content in the sintering material layer 8%. The mixed sintering material enters the sintering machine through the mixing tank for sintering. The sintered ore enters the ring cooler for cooling. The sintered ore enters the screening device for screening. The sintered ore with a particle size of 12-25mm is filtered into the silo for storing the bottom material. Before the sintering material is placed on the sintering machine trolley, the bottom material in the above silo is spread to a thickness of 20-40mm, so that the thickness of the entire material layer after the material is placed is controlled at 1000mm-1050mm. The gap between the grate bars of the sintering machine is 3-5mm, and some of the sintered ore is sent back to the batching bin and the mixing tank for reuse. The sintered ore that meets the requirements enters the blast furnace for production.

[0035] Embodiment 2:

[0036] Different from the first embodiment, in this embodiment, after the sintering material enters the batching bin, quicklime with an activity of more than 300mL and a CaO (calcium oxide) content of 85-91% is simultaneously input into the batching bin by wind power; during the stirring process of the first mixer, hot water is added to a mixing device to make the hot water content in the sintering material layer 8.5%; mixed steam above 200°C is sprayed into the mixing tank to increase the material temperature to 88-96°C; the sintered ore with a particle size of 12-20mm is filtered into a silo specifically for storing the bottom material, and before the sintering material is placed on the sintering machine trolley, the bottom material in the above silo is spread to a thickness of 30-40mm, so that the thickness of the entire material layer after the material is placed is controlled to be 1000mm-1050mm. The grate gap of the sintering machine is 5-7mm. Compared with the first embodiment, the technical solution used in this embodiment increases the sintering speed of the sintering machine by about 5%, with good economic effect.

[0037] In the actual sintering production process, after the sintering material enters the batching bin, quicklime with an activity of more than 300mL and a CaO (calcium oxide) content of 85-91% is input into the batching bin by wind. After passing through the batching bin, the sintering material passes through the first mixer, the second mixer and the strong mixer in sequence and then enters the mixing tank. During the stirring process of the first mixer, hot water is added to the first mixing device so that the hot water content in the sintering material layer is 7.9-9.3%.

[0038] The mixed sintering material enters the sintering machine through the mixing trough for sintering. The sintered ore enters the ring cooler for cooling. The steam released in this process is introduced into the secondary mixing device and the mixing trough to increase the material temperature of the sintering material to 88-96°C.

[0039] The sintered ore enters the screening device for screening, and the sintered ore with a particle size of 12 to 20 mm is filtered into a silo specifically used to store the bottom material. Before the sintered material is placed on the sintering machine trolley, the bottom material in the silo is spread to a thickness of 30 to 40 mm. The gap between the grate bars of the sintering machine is 5 to 7 mm. Some of the sintered ore is sent back to the batching silo and the mixing trough for reuse, and the sintered ore that meets the requirements enters the blast furnace for production.

[0040] The advantages and positive effects of the present invention are as follows: quicklime with an activity of more than 300 mL and a CaO content of 85-91% is added to a batching bin; during the stirring process of the first mixer, hot water is added to the first mixing device to make the hot water content in the sintering material layer be 7.9-9.3%; the steam released during the cooling process of the ring cooler is introduced into the second mixing device and the mixing material tank to increase the material temperature to 88-96°C; sintered ore with a particle size of 12-20 mm is screened out for use as a base material, the thickness of the base material is 30-40 mm, and the material layer thickness is controlled to be 1000 mm-1050 mm; the grate gap of the sintering machine is 5-7 mm, and by adjusting multiple parameters in the sintering process, the sintering speed is increased by about 5% while the air permeability of the sintering material layer is improved, thereby achieving better economic effects.

[0041] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for improving the air permeability of a sintering material layer, characterized in that: The steps include: The sintering machine lays the base material before spreading the material; The sintered ore after sintering in the sintering machine enters the ring cooler for cooling. The steam released in this process is introduced into the secondary mixing device and the mixing tank to increase the material temperature of the sintering material to the set value.

2. The method for improving the air permeability of a sintered material layer according to claim 1, characterized in that: The bed material comes from the sintered ore after screening.

3. The method for improving the air permeability of a sintered material layer according to claim 2, characterized in that: The sintered ore is cooled by the ring cooler and then enters a screening device for screening. The sintered ore with a satisfactory particle size is used as the base material.

4. The method for improving the air permeability of a sintering material layer according to claim 3, characterized in that: The granularity of the base material is 12-20 mm and the thickness is 30-40 mm.

5. The method for improving the air permeability of a sintering material layer according to claim 1, characterized in that: The set value is 88-96°C.

6. The method for improving the air permeability of a sintering material layer according to any one of claims 1 to 5, characterized in that: The sintering material in the batching bin passes through the first mixing device, the second mixing device and the strong mixing device in sequence and then enters the mixing tank.

7. The method for improving the air permeability of a sintering material layer according to claim 6, characterized in that: The first mixing device is provided with hot water so that the hot water content in the sintering material layer is 7.9-9.3%.

8. The method for improving the air permeability of a sintering material layer according to claim 7, characterized in that: After the base material is laid, the material is laid so that the thickness of the entire material layer is controlled within the range of 1000 mm to 1050 mm.

9. The method for improving the air permeability of a sintering material layer according to claim 8, characterized in that: Quicklime with an activity of more than 300 mL and a CaO content of 85-91% is added to the batching bin.

10. The method for improving the air permeability of a sintering material layer according to any one of claims 7 to 9, characterized in that: The grate bar gap of the sintering machine is 5 to 7 mm.

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