A pre-treatment dust removal system for pellet iron concentrate

Abstract

The pellet iron concentrate pretreatment dust removal system disclosed in the application comprises a first dust removal assembly and a second dust removal assembly, the first dust removal assembly is communicated with a dust generation point of a dryer through a first dust removal pipeline, the second dust removal assembly is communicated with a dust generation point of a high-pressure roller mill, a dust generation point of an auxiliary material bin, a dust generation point of a metering scale and a dust generation point of a mixer through a second dust removal pipeline, and the dust discharge port of the first dust remover and the dust discharge port of the second dust remover are respectively communicated with the material conveying pipeline of the pellet iron concentrate pretreatment system. The pellet iron concentrate pretreatment dust removal system adopts a double-branch dust removal assembly design, can solve the problem that a single dust removal device cannot adapt to complex dust working conditions in the whole process, can improve the conditions of condensation blockage of the dust removal pipeline, hardening and damage of the filter material, and fluctuation of the dust removal effect, and meanwhile, the dust discharge ports of the first dust remover and the second dust remover are communicated with the material conveying pipeline of the pellet iron concentrate pretreatment system, which can improve the recycling rate of dust.

Description

Technical Field

[0001] This application relates to the field of dust removal technology, and more specifically, to a dust removal system for pretreatment of iron concentrate pellets. Background Technology

[0002] Iron pellets are an important raw material for blast furnace ironmaking, and their production process typically includes multiple stages such as iron concentrate pretreatment, batching and mixing, pelletizing, drying and preheating, and roasting and solidification. The iron concentrate pretreatment stage involves multiple processes such as crushing, screening, drying, conveying, weighing, and grinding. Large amounts of dust-laden gas are generated at the inlet / outlet, transfer points, and discharge points of each process. If these dust-laden gases are not effectively controlled, it will not only cause serious dust pollution and endanger the health of workers, but also lead to the loss and waste of a significant amount of iron concentrate resources.

[0003] Currently, the dust-laden gas generated in the iron concentrate pretreatment stage of pellet plants is mainly treated by filtration dust removal equipment. This approach has the following problems: First, because the dust contains temperature and moisture, the dust removal pipes are very prone to clogging and caking; second, the filter material is easily damaged prematurely due to dust adhesion and caking, increasing operation and maintenance costs; and third, the dust recovery and utilization rate is low.

[0004] Therefore, how to balance the operational stability of the dust removal system with the resource utilization of the recovered dust has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a dust removal system for pretreatment of iron ore pellets, so as to balance the operational stability of the dust removal system and the resource utilization of the recovered dust.

[0006] To achieve the above objectives, this application provides the following technical solution: A dust removal system for pretreatment of iron ore pellets, comprising a dryer, a buffer weighing hopper, a high-pressure roller mill, an auxiliary material silo, a weighing scale, and a mixer, wherein the dryer, the buffer weighing hopper, the high-pressure roller mill, and the mixer are arranged sequentially along the material flow direction, and the weighing scale is located at the discharge port of the auxiliary material silo and upstream of the mixer; The dust removal system includes a first dust removal component and a second dust removal component. The first dust removal component is connected to the dust generation point of the dryer through a first dust removal pipeline. The second dust removal component is connected to the dust generation point of the high-pressure roller mill, the dust generation point of the auxiliary material silo, the dust generation point of the weighing scale, and the dust generation point of the mixer through a second dust removal pipeline. The first dust removal component includes a first dust collector, and the second dust removal component includes a second dust collector. The ash discharge ports of the first dust collector and the second dust collector are respectively connected to the material conveying pipeline of the pellet iron concentrate pretreatment system.

[0007] Optionally, in the above-mentioned pellet iron concentrate pretreatment dust removal system, the first dust removal component includes a first dust collector and a first fan. The first fan is connected to the air outlet of the first dust collector. The dryer has a feed inlet, a discharge outlet, and a pressure relief outlet. The feed inlet, the discharge outlet, and the pressure relief outlet are respectively connected to the first dust removal pipeline.

[0008] Optionally, in the above-mentioned pellet iron concentrate pretreatment dust removal system, the second dust removal component includes a second dust collector and a second fan. The second fan is connected to the air outlet of the second dust collector along the gas flow direction. The second dust collector includes an inertial separation module and a filtration module.

[0009] Optionally, in the above-mentioned pellet iron concentrate pretreatment dust removal system, the filter module is a modified fiber composite filter layer.

[0010] Optionally, in the above-mentioned pellet iron concentrate pretreatment dust removal system, the second dust removal component includes a first dust collection hood, which is a closed hood, and the high-pressure roller mill is housed inside the first dust collection hood. The first dust collection hood is connected to the second dust removal pipeline, and the second dust removal pipeline is connected to the second dust collector.

[0011] Optionally, in the above-mentioned pellet iron concentrate pretreatment dust removal system, the second dust removal component includes a second dust collection hood. The discharge port of the auxiliary material silo, the conveying area of ​​the metering scale, and the discharge port of the metering scale are respectively provided with the second dust collection hood, and each of the second dust collection hoods is connected to the second dust removal pipeline.

[0012] Optionally, in the above-mentioned pellet iron concentrate pretreatment dust removal system, the first dust collector is a bag filter.

[0013] Optionally, in the above-mentioned pellet iron concentrate pretreatment dust removal system, the pellet iron concentrate pretreatment dust removal system includes a detection component and a control system. The detection component is installed at the dust generation point of the dryer, the dust generation point of the high-pressure roller mill, the dust generation point of the auxiliary material silo, the dust generation point of the metering scale, and the dust generation point of the mixer. The system also includes a first dust removal pipeline, a second dust removal pipeline, a first dust collector, and a second dust collector. The detection component includes at least a dust concentration detection element, a temperature detection element, a pressure detection element, and an airflow detection element, for collecting dust concentration, temperature, airflow, and pressure parameters of the dust-laden gas. The concentration detection element, the temperature detection element, the pressure detection element, and the airflow detection element are respectively connected to the control system signal.

[0014] Optionally, in the above-mentioned pellet iron concentrate pretreatment dust removal system, the first fan of the first dust removal component and the second fan of the second dust removal component are respectively connected to the control system. The control system controls the operating frequency of the first fan and / or the second fan according to the detection signals of the air volume detection element and / or the pressure detection element. When the real-time operating parameters indicate an increase in dust load or insufficient suction capacity, the operating frequency of the corresponding fan should be increased. When the real-time operating parameters indicate a decrease in dust generation load and excessive suction, the operating frequency of the corresponding fan is reduced.

[0015] As can be seen from the above scheme, the dust removal system for pretreatment of iron concentrate pellets disclosed in this application adopts a dual-branch dust removal component design with differentiated dust removal for different processes. The first dust removal component is adapted for dust with high temperature, high humidity, and large particle size in the drying process, while the second dust removal component is adapted for dust with high humidity, fine, and high viscosity in the roller pressing and mixing process. This can solve the problem that a single dust removal device cannot adapt to the complex dust conditions of the entire process, and can improve the situation of condensation and blockage in dust removal pipelines, filter material caking and damage, and fluctuations in dust removal effect. At the same time, the ash discharge ports of the first and second dust collectors are connected to the material conveying pipeline of the pretreatment system for iron concentrate pellets, which can recover and utilize iron concentrate dust, thereby reducing the loss of iron concentrate and improving the dust recovery and utilization rate. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the dust removal system for pretreatment of iron concentrate pellets disclosed in an embodiment of this application.

[0018] The annotations in the attached figures are explained as follows: 10 Dryer, 20 Buffer Weighing Hopper, 30 High-Pressure Roller Mill, 40 Auxiliary Material Silo, 50 Measuring Scale, 60 Mixer, 70 Gas Furnace; 100 First dust removal component, 110 First dust collector, 120 First fan, 130 First dust removal pipeline, 140 First chimney, 150 First dust recovery pipeline; 200 Second dust removal component, 210 Second dust collector, 220 Second fan, 230 First dust collection hood, 240 Second dust collection hood, 250 Third dust collection hood, 260 Second chimney, 270 Second dust removal pipeline, 280 Second dust recovery pipeline, 290 Fourth dust collection hood. Detailed Implementation

[0019] The core of this application is to disclose a dust removal system for pretreatment of iron ore pellets, so as to balance the operational stability of the dust removal system and the resource utilization of the recovered dust.

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Iron pellets are an important raw material for blast furnace ironmaking, and their production process typically includes multiple stages such as iron concentrate pretreatment, batching and mixing, pelletizing, drying and preheating, and roasting and consolidation. Among these, iron concentrate pretreatment is a crucial step in processing iron concentrate raw materials into materials that meet pelletizing requirements. This involves multiple processes such as crushing, screening, drying, batching, and grinding, and includes equipment such as dryers, buffer weighing hoppers, high-pressure roller mills, and high-intensity mixers. During the pretreatment process, large amounts of dust-laden gas are generated at the inlet and outlet of each piece of equipment, the material discharge point, and the material transfer point. If these dust-laden gases are not effectively treated, they will not only cause serious dust pollution, endangering the health of workers, but also lead to the loss and waste of a large amount of iron concentrate resources. Furthermore, since the dust-laden gas from iron concentrate usually has a certain temperature and humidity, existing dust removal equipment suffers from problems such as easy pipe blockage and filter media damage, affecting the continuity and economy of production. This application is an improvement based on the above background.

[0022] First, the iron concentrate pretreatment system will be introduced, such as... Figure 1 As shown, along the material flow direction, the dryer, buffer weighing hopper, high-pressure roller mill and mixer are arranged in sequence. The weighing scale is set at the discharge port of the auxiliary material silo and is located upstream of the mixer so that the auxiliary material enters the mixer after being weighed and is mixed with the iron concentrate after being roller-pressed. The gas furnace 70 provides a continuous and stable heat source for the dryer to control the drying temperature and drying rate.

[0023] like Figure 1As shown in the figure, this application discloses a dust removal system for pretreatment of iron ore pellets, including a first dust removal component 100 and a second dust removal component 200. The first dust removal component 100 is connected to the dust generation point of the dryer 10 through a first dust removal pipeline 130 and is used to treat the dust-laden gas generated by the dryer 10. The second dust removal component 200 is connected to the dust generation point of the high-pressure roller mill 30, the dust generation point of the auxiliary material silo 40, and the dust generation point of the mixer 60 through a second dust removal pipeline 270 and is used to treat the dust-laden gas generated by the high-pressure roller mill 30, the auxiliary material silo 40, the weighing scale 50, and the mixer 60.

[0024] The dust-laden gas in the drying process is characterized by high temperature, high humidity, large particle size, and high dust concentration. In contrast, the dust-laden gas in the rolling, batching, and mixing processes is characterized by normal temperature, high humidity, fine dust particles, and strong adhesion. Therefore, this application divides the drying process and the rolling, batching, and mixing processes into different dust removal branches. By adopting a dual-branch dust removal structure, the dust-laden gas under different operating conditions can enter the corresponding dust removal components separately, avoiding the problem of uneven air volume distribution and local blockage caused when all dust-generating points share the same dust removal branch.

[0025] Furthermore, the first dust removal assembly 100 includes a first dust collector 110, and the second dust removal assembly 200 includes a second dust collector 210. The ash discharge ports of the first dust collector 110 and the second dust collector 210 are respectively connected to the material conveying pipeline of the pellet iron concentrate pretreatment system. Specifically, the ash discharge port of the first dust collector 110 is connected to the material conveying pipeline of the pellet iron concentrate pretreatment system through a first dust recovery pipeline 150, and the ash discharge port of the second dust collector 210 is connected to the material conveying pipeline of the pellet iron concentrate pretreatment system through a second dust recovery pipeline 280. The iron concentrate dust collected by the first dust collector 110 and the second dust collector 210 can be returned to the material conveying path of the pretreatment system instead of being discharged as waste dust. Since the recovered dust still enters the subsequent batching, rolling, or mixing processes, it helps to reduce the loss of iron concentrate.

[0026] The pellet iron concentrate pretreatment dust removal system disclosed in this application adopts a dual-branch dust removal component design. The first dust removal component 100 is adapted for dust with high temperature, high humidity, and large particle size in the drying process, while the second dust removal component 200 is adapted for dust with high humidity, fine, and high viscosity in the roller pressing and mixing process. This can solve the problem that a single dust removal device cannot adapt to the complex dust conditions of the entire process, and can improve the situation of condensation and blockage in the dust removal pipeline, filter material caking and damage, and fluctuation in dust removal effect. At the same time, the ash discharge ports of the first dust collector 110 and the second dust collector 210 are connected to the material conveying pipeline of the pellet iron concentrate pretreatment system, which can recover and utilize iron concentrate dust, thereby reducing the loss of iron concentrate and improving the dust recovery and utilization rate. Since the first dust removal component 100 and the second dust removal component 200 form collection, conveying, filtering and recycling paths for different processes, the dust-laden gas is introduced into the dust removal system near the dust generation point. After being collected by the dust collector, the dust flows back to the material conveying pipeline. Therefore, the dust removal system can take into account both dust control and resource recovery.

[0027] In some specific embodiments of this application, such as Figure 1 As shown, the dryer 10 can be a cylindrical dryer. Specifically, the dryer 10 has a feed inlet, a discharge outlet, and a pressure relief port, all of which can serve as dust-generating points. A first dust collection pipeline 130 is connected to the feed inlet, discharge outlet, and pressure relief port, ensuring that dust-laden gas generated during feeding, discharging, and internal pressure fluctuations in the dryer 10 is drawn into the first dust collection pipeline 130. Because multiple dust-generating points of the dryer 10 are connected to the first dust collector 110, the dust-laden gas is collected in its initial stage, preventing dust from easily spreading into the workshop environment.

[0028] Specifically, such as Figure 1 As shown, the first dust removal assembly 100 includes a first dust collector 110 and a first fan 120. The first fan 120 is connected to the outlet of the first dust collector 110. During operation, the first fan 120 creates a negative pressure within the first dust collector 110 and the first dust removal pipeline 130. Dust-laden gas at the dust generation point of the dryer 10 enters the first dust collector 110 through the first dust removal pipeline 130. The dust is intercepted by the first dust collector 110, and the purified gas is discharged to the first chimney 140 through the first fan 120. Since the first fan 120 is located on the outlet side of the first dust collector 110, a stable suction airflow can be formed on the inlet side of the first dust collector 110, allowing dust-laden gas near the feed inlet, discharge outlet, and pressure relief port of the dryer 10 to enter the first dust collector 110 along a predetermined path, thereby reducing the unorganized dispersion of dust-laden gas.

[0029] In some embodiments, the first dust collector 110 is preferably a baghouse dust collector, which contains filter bags. When dust-laden gas passes through the filter bags, the dust is trapped on the outer surface of the filter bags, and the purified gas enters the clean air chamber. Exemplarily, the filter bags can be made of waterproof and oil-resistant membrane-coated polytetrafluoroethylene (PTFE) filter material, i.e., waterproof and oil-resistant membrane-coated PTFE filter material. Because the surface of the membrane-coated filter material is relatively dense and the intermolecular adhesion of PTFE material to dust is extremely weak, moist dust is not easily embedded deep into the filter material, making it easier for dust to detach from the filter material surface during cleaning. Therefore, it can reduce the impact of dust adhesion and caking on the air permeability of the filter material.

[0030] Furthermore, the filtration velocity of the first dust collector 110 can be no greater than 0.85 m / min, for example, it can be 0.65 m / min, 0.75 m / min, 0.85 m / min, or any two of the above values. By controlling the filtration velocity within a lower range, the dust-laden gas load per unit area of ​​the filter material is reduced, and the accumulation rate of dust on the filter material surface is correspondingly slowed down; under the same dust removal conditions, the upward trend of the filter bag pressure difference is slower, which is beneficial to improving the operational stability of the first dust collector 110; at the same time, the lower velocity can reduce the scouring and wear of high-speed dust particles on the filter material surface, further extending the service life of the filter bags.

[0031] In some embodiments of this application, the outer wall of the first dust removal pipeline 130 is provided with a heat tracing structure. This heat tracing structure may include an insulation layer covering the outside of the first dust removal pipeline 130 and a heat tracing element disposed inside the insulation layer or outside the pipeline wall. The heat tracing element may be an electric heat tracing cable, a steam heat tracing pipe, a hot water heat tracing pipe, or other structures capable of providing heat to the first dust removal pipeline 130. For example, the heat tracing temperature of the first dust removal pipeline 130 may be controlled between 65°C and 85°C, such as 70°C, 75°C, or 80°C. Since the first dust removal pipeline 130 carries warm, humid gas generated by the dryer 10, the heat tracing structure can reduce the possibility of condensation caused by the pipeline wall temperature falling below the dew point, making it less likely for dust to adhere to the pipeline wall due to moisture condensation.

[0032] Furthermore, the negative pressure within the first dust removal pipeline 130 can be from -800Pa to -1200Pa, for example, -900Pa, -1000Pa, or -1100Pa, preferably -1000Pa. By maintaining the first dust removal pipeline 130 within the aforementioned negative pressure range, sufficient collecting airflow can be formed at the dust generation point of the dryer 10; at the same time, compared to operating with excessively high negative pressure, this negative pressure range can prevent excessive suction from causing a large amount of material to be carried out of the dryer 10, thus balancing dust collection and stable material conveying.

[0033] In some specific embodiments of this application, the ash discharge port of the first dust collector 110 is equipped with a first ash discharge device. Specifically, the first ash discharge device can be a rotary valve, a flap valve, or other airlock ash discharge equipment, or a conveying device such as a screw conveyor. For example, the first ash discharge device is a rotary automatic ash discharge device, and the ash discharge frequency can be 5 to 15 minutes per cycle, for example, 8 minutes per cycle, 10 minutes per cycle, or 12 minutes per cycle. The outlet of the first ash discharge device can be connected to the material conveying pipeline of the pellet iron concentrate pretreatment system, for example, it can be connected to the discharge port of the dryer 10, so that the dust collected by the first dust collector 110 flows back to the material conveying pipeline of the pellet iron concentrate pretreatment system. Because the ash discharge device can maintain a relatively sealed state at the bottom of the first dust collector 110 during ash discharge, the first dust collector 110 is less prone to significant air leakage due to ash discharge, which is beneficial to maintaining the stable negative pressure of the first dust collection assembly 100.

[0034] In some specific embodiments of this application, such as Figure 1 As shown, the second dust removal assembly 200 includes a second dust collector 210 and a second fan 220. The second fan 220 is connected to the outlet of the second dust collector 210. Specifically, the second dust removal pipeline 270 is connected to the dust generation points of the high-pressure roller mill 30, the auxiliary material silo 40, the metering scale 50, and the mixer 60, respectively. During operation, the second fan 220 creates a negative pressure within the second dust collector 210 and the second dust removal pipeline 270. The dust-laden gas generated by the high-pressure roller mill 30, the auxiliary material silo 40, the metering scale 50, and the mixer 60 enters the second dust collector 210 through the second dust removal pipeline 270, and the purified gas is discharged to the second chimney 260 through the second fan 220.

[0035] Specifically, along the gas flow direction, the second dust collector 210 includes an inertial separation module and a filtration module. The inertial separation module is located at the front end of the second dust collector 210, and the filtration module is located at the rear end of the inertial separation module. Dust-laden gas first enters the inertial separation module, where the airflow direction and velocity change. Larger dust particles with higher diameters and masses are separated from the main airflow due to inertia. Subsequently, the gas containing fine dust enters the filtration module, where the fine dust is further trapped. Because larger dust particles are partially separated before entering the filtration module, the dust load on the filtration module is reduced, thus mitigating filter clogging and pressure differential increases.

[0036] For example, the inertial separation module includes multiple sets of separation elements arranged sequentially along the airflow direction. These separation elements are selected from one or more combinations of inclined louvered blades, corrugated baffles, and hook-shaped blades. As the dust-laden gas flows through the separation elements, it is forced to change direction multiple times. Coarse dust particles deviate from the airflow direction due to inertia, impact the surface of the separation elements, lose kinetic energy, and slide down the surface to the dust collection area below, thus achieving gas-solid separation. Preferably, the gap between adjacent separation elements is adjustable to accommodate the collection requirements of dust particles of different sizes. In one possible implementation, taking baffles as an example, the ends of the baffles are bolted to the side plate of the inertial separation module's housing. The side plate has adjustment holes extending along the airflow direction. Bolts pass through these adjustment holes and can slide and lock along them to adjust the gap between adjacent baffles. Because coarse particles in the airflow are separated upstream, the downstream filtration module mainly handles smaller dust particles, resulting in a more uniform dust layer on the filter surface and relatively reduced pressure fluctuations required for cleaning.

[0037] Furthermore, the module velocity within the inertial separation module can be between 2.0 m / s and 2.5 m / s, for example, 2.1 m / s, 2.3 m / s, or 2.5 m / s. By maintaining an appropriate flow velocity of the gas within the inertial separation module, the dust-laden gas can generate sufficient inertial separation without causing the settled dust to be re-entrained due to excessive flow velocity, thereby improving the stability of the coarse separation in the front-end inertial separation module.

[0038] In some embodiments of this application, the filtration module is a modified fiber composite filter layer. Exemplarily, along the gas flow direction, the modified fiber composite filter layer includes a dust-receiving layer, a filter layer, and a support layer arranged sequentially. The dust-receiving layer is a water- and oil-repellent modified fiber layer, which can be made of polyester fiber impregnated with a fluorinated finishing agent. The filter layer is an ultrafine fiber layer, specifically made of polyphenylene sulfide fiber using a melt-blown process. The support layer is a base fabric layer, specifically made of polyester fiber using a needle-punching process. The layers are bonded together by hot-pressing or adhesive bonding. It should be noted that the above structure is merely an example, and this application is not limited thereto. The specific materials and manufacturing processes of each layer can be adapted to the actual working conditions. Due to the high humidity, high viscosity, and fine characteristics of the dust in the rolling, batching, and mixing processes, the modified fiber composite filter layer can form multi-level interception channels between the fibers, allowing fine dust to be captured on the filter layer surface. Simultaneously, the modification treatment reduces the adhesion strength between the dust and the fiber surface, making it easier for the dust to fall off during cleaning.

[0039] Furthermore, the filtration velocity of the filter module can be from 0.7 m / min to 0.85 m / min, for example, 0.72 m / min, 0.78 m / min or 0.82 m / min, preferably 0.8 m / min. When this filtration velocity is used in conjunction with the modified fiber composite filter layer, it can relatively increase the residence time of dust-laden gas in the filter layer, increasing the chance of fine dust being trapped. At the same time, the lower filtration velocity can reduce the tendency of dust to embed deep into the filter layer, which is beneficial to maintaining the cleanability of the filter module. It can improve the situation of traditional bag dust collectors that are prone to bag clogging, easy to caking, and rapid filter material wear, and improve the purification efficiency of complex dust and the stability of equipment operation.

[0040] The ash discharge port of the second dust collector 210 is connected to the material conveying pipeline of the pellet iron concentrate pretreatment system. In one possible implementation, the dust collected by the second dust collector 210 is returned to the feed end of the mixer 60 through the second dust recovery pipeline 280. Since the second dust collector 210 mainly collects dust from the rolling, batching, and mixing processes, returning it to the feed end of the mixer 60 allows the dust to enter the mixing process along with the iron concentrate, eliminating the need for a separate dust removal and treatment process.

[0041] In some embodiments of this application, the second dust collection assembly 200 includes a first dust collection hood 230. Preferably, the first dust collection hood 230 is a closed hood, and the high-pressure roller mill 30 is housed inside the first dust collection hood 230. The first dust collection hood 230 is connected to a second dust collection pipeline 270, and the second dust collection pipeline 270 is connected to a second dust collector 210. Exemplarily, the first dust collection hood 230 surrounds the outside of the high-pressure roller mill 30, so that the feed inlet, rolling area, and discharge outlet of the high-pressure roller mill 30 are all located within the dust collection space defined by the first dust collection hood 230. Figure 1 The structure of the dust collection hood shown is merely an illustrative example of this application and does not constitute a specific limitation on the structure of the dust collection hood in this application.

[0042] Furthermore, the interior of the first dust collection hood 230 can maintain a slight negative pressure of -150 Pa to -300 Pa, for example, -180 Pa, -220 Pa, or -260 Pa, preferably -200 Pa. Since the high-pressure roller mill 30 generates localized dust during material rolling, the enclosed space formed by the first dust collection hood 230 restricts the dust diffusion boundary. Simultaneously, the slight negative pressure inside the hood causes the airflow direction at the hood gaps to tend from the outside to the inside; therefore, even if there are gaps in the first dust collection hood 230, dust-laden gas is not easily dispersed from the hood into the workshop. Preferably, the first dust collection hood 230 is equipped with an inspection window and an observation window for convenient maintenance and observation.

[0043] During the operation of the high-pressure roller mill 30, the dried iron concentrate is subjected to strong extrusion and deformation. The high-temperature and humid air trapped inside the material is instantly and rapidly released, expands, and overflows, generating a large amount of high-concentration, high-humidity, fine-particle dust. The dust concentration generated in this process is approximately 800 mg / Nm³. 3 The dust moisture content is approximately 12% to 15%, which falls under the category of high-temperature, high-humidity, and high-viscosity dust that is difficult to handle. This type of dust has strong suspension properties and a rapid diffusion rate, making it the most significant source of high-pollution dust in the pretreatment workshop. This application employs a fully enclosed first dust collection hood 230 to completely cover the high-pressure roller mill 30, implementing sealed air collection at the discharge port, crushing and dropping point, and cake transfer point. This effectively blocks the dust escape channels and provides stable air collection conditions for efficient dust removal at the downstream end.

[0044] In some specific embodiments of this application, such as Figure 1 As shown, the second dust removal component 200 includes a second dust collection hood 240. Specifically, the discharge port of the auxiliary material silo 40, the conveying area of ​​the weighing scale 50, and the discharge port of the weighing scale 50 are each equipped with a second dust collection hood 240, and each second dust collection hood 240 is connected to the second dust removal pipeline 270. The second dust collection hood 240 is preferably a sealed dust collection hood. It should be noted that the sealed dust collection hood here refers to a collection device that can form a closed negative pressure space with the dust source equipment. Specifically, the sealed dust collection hood can be a partially sealed hood, a ring hood, or a special-shaped hood adapted to the equipment interface, etc.; in the case of limited installation space, a side suction hood or an upper suction hood with a soft curtain enclosure can also be used to enable it to have a sealed air collection function. When the auxiliary material enters the weighing scale 50 from the discharge port of the auxiliary material silo 40, the impact and drop of the material will cause air disturbance and generate dust; by setting the second dust collection hood 240 at the discharge port, the dust raised is sucked in at the initial stage of diffusion. After the second dust collection hood 240 is installed in the conveying area of ​​the weighing scale 50, the fine dust generated during the weighing and conveying process can be confined within the hood. After the second dust collection hood 240 is installed at the material discharge port of the weighing scale 50, the dust-laden gas generated by the material discharge impact is introduced into the second dust removal pipeline 270, thereby reducing the escape of dust from the batching area.

[0045] During the feeding, metering, conveying, and impact of auxiliary materials, fine dry dust is easily generated. The dust particle size is concentrated between about 5μm and 20μm. This dust mixes with the wet dust emitted from the front roller pressing, forming a complex dry-wet mixed dust system. Conventional dust removal equipment is difficult to collect stably. By setting a second dust collection hood 240, the dust generated throughout the entire batching process can be collected uniformly and sent to the second dust removal branch, realizing the dust collection of the batching process. In some specific embodiments, the dust collection rate can reach 99.5%.

[0046] Furthermore, the vent velocity of the second dust collection hood 240 can be from 1.2 m / s to 1.8 m / s, for example, 1.3 m / s, 1.5 m / s, or 1.7 m / s, preferably 1.5 m / s. By maintaining the vent velocity as described above, the second dust collection hood 240 can form a collecting airflow towards the inside of the hood around the dust generation point. At the same time, this airflow velocity will not excessively suck up normally falling material, thus achieving a balance between dust collection and material metering stability.

[0047] In some embodiments of this application, such as Figure 1 As shown, the second dust removal component 200 includes a third dust collection hood 250. Specifically, the top of the mixer 60 and the discharge port of the mixer 60 are respectively equipped with third dust collection hoods 250, which are connected to the second dust removal pipeline 270. The iron concentrate powder cake after high-pressure roller pressing and the precisely proportioned auxiliary materials are simultaneously fed into the mixer 60 for high-speed and powerful stirring and homogenization, so that the main materials and auxiliary materials are fully integrated to obtain a pelletizing mixture with uniform composition, moisture, and particle size, which meets the requirements of the oxidized pelletizing process. During the high-speed stirring process of the mixer 60, the materials violently tumble, collide, and rub, which continuously generates a large amount of fine suspended dust. Moreover, the dust in the mixing process has high humidity and strong viscosity, which easily adheres to the surface of the filter material and causes caking and blockage. By setting the third dust collection hoods 250 at the top of the mixer 60 and the discharge port respectively, the dust can be captured by airflow during the mixing process and the discharge process, so that the dust generated at different stages enters the second dust removal pipeline 270.

[0048] It should be noted that the first dust collection hood 230, the second dust collection hood 240, and the third dust collection hood 250 can be installed simultaneously, or at least one of them can be selected based on the distribution of dust generation points. For production lines with high dust levels from the high-pressure roller mill 30, the first dust collection hood 230 can be prioritized; for production lines with large drop differences in auxiliary material batching or significant dust generation in the metering area, the second dust collection hood 240 can be added; for production lines with strong discharge impact from the mixer 60, the third dust collection hood 250 can be added. This modular combination allows the dust removal system to adapt to pellet production lines of different scales and equipment layouts.

[0049] In some embodiments of this application, the negative pressure within the second dust removal pipeline 270 can be from -1500 Pa to -2200 Pa, for example -1700 Pa, -1900 Pa, or -2100 Pa, preferably -1800 Pa. Since the dust-generating points of the high-pressure roller mill 30, auxiliary material silo 40, metering scale 50, and mixer 60 are relatively dispersed, maintaining the aforementioned negative pressure range in the second dust removal pipeline 270 can create a stable suction airflow at multiple dust collection points, allowing the dust-laden gas to preferentially enter the dust collection hood and the second dust removal pipeline 270, without diffusing into the external environment.

[0050] In some specific embodiments of this application, such as Figure 1 As shown, the second dust removal assembly 200 includes a fourth dust collection hood 290, which is used to collect dust from the outlet pipe of the dryer 10. A check valve is installed on the outlet pipe of each dust collection hood.

[0051] In some specific embodiments of this application, the dust removal system for pretreatment of iron ore concentrate pellets includes a detection component and a control system. Specifically, the detection component is installed at the dust generation points of the dryer 10, the high-pressure roller mill 30, the auxiliary material silo 40, the weighing scale 50, and the mixer 60, and is also installed in the first dust removal pipeline 130, the second dust removal pipeline 270, the first dust collector 110, and the second dust collector 210. The detection component includes at least a dust concentration detection element, a temperature detection element, a pressure detection element, and an airflow detection element to collect the dust concentration, temperature, airflow, and pressure parameters of the dust-laden gas. The dust concentration detection element, temperature detection element, pressure detection element, and airflow detection element are respectively connected to the control system signal.

[0052] Specifically, dust concentration detection elements can be installed near each dust-generating point, at the outlet of the first dust collector 110, at the outlet of the second dust collector 210, or in the clean air chamber of the corresponding dust collector to monitor dust generation intensity and emission concentration changes; temperature detection elements can be installed at the inlets of the first dust removal pipeline 130, the second dust removal pipeline 270, and the first dust collector 110 and the second dust collector 210 to determine whether the temperature of the dust-laden gas is within a suitable range; pressure detection elements can be installed at the inlets and outlets of each dust removal pipeline, each dust collection hood, and each dust collector to monitor pipeline negative pressure and hood negative pressure; air volume detection elements can be installed in the main or branch pipes of the first dust removal pipeline 130 and the second dust removal pipeline 270 to monitor the air volume distribution of each branch.

[0053] Because the detection components can establish multi-location detection at dust generation points, within each dust collection pipeline, and inside each dust collector, the control system can determine the amount of dust generated, the flow status of the pipeline, and the operating status of the filter media based on the detection signals from different locations. For example, when the pressure and airflow of the first dust collection pipeline 130 continuously decrease, the control system can determine that there is a risk of blockage in the pipeline; when the dust concentration at the outlet of the first dust collector 110 or the second dust collector 210 increases abnormally, the control system can determine that the filter media is damaged or at risk of sealing failure. Therefore, faults can be detected and repaired promptly.

[0054] The first fan 120 of the first dust removal component 100 and the second fan 220 of the second dust removal component 200 are respectively connected to the control system. The control system is configured to adjust the operating frequency of the first fan and / or the second fan according to the real-time operating parameters of each dust-generating point. When the real-time operating parameters indicate an increase in dust generation load or insufficient suction capacity, the operating frequency of the corresponding fan is increased. When the real-time operating parameters indicate a decrease in dust generation load and excessive suction, the operating frequency of the corresponding fan is decreased.

[0055] When the dust concentration at a dust-generating point increases or the airflow in the corresponding dust collection pipeline falls below a preset airflow threshold, the control system increases the operating frequency of the corresponding fan to enhance the suction capacity of that dust collection branch and strengthen dust collection. When the dust concentration at the dust-generating point decreases and the negative pressure in the corresponding dust collection pipeline exceeds a preset negative pressure threshold, the control system reduces the operating frequency of the corresponding fan to avoid energy waste caused by excessive suction. Through this adjustment method based on actual working conditions, the fan does not need to operate at its highest frequency for extended periods, thus reducing unnecessary energy consumption. Simultaneously, when dust generation intensity increases, the fan can promptly increase its suction capacity, ensuring that the dust-laden gas still enters the corresponding dust collector along the dust collection hood and dust collection pipeline.

[0056] For example, both the first fan 120 and the second fan 220 can be variable frequency fans, and the frequency range of the fans can be 30Hz to 50Hz, such as 35Hz, 40Hz, 45Hz or 50Hz, preferably 40Hz.

[0057] Furthermore, the response delay time of the control system can be no more than 2 seconds. Here, the response delay can be understood as the time between the detection component acquiring an abnormal signal and the control system outputting a corresponding control command. Since the feeding, rolling, and mixing processes in the pellet iron concentrate pretreatment process have certain instantaneous fluctuations, a shorter response delay time allows the fan frequency, dust removal parameters, or alarm signals to quickly follow changes in operating conditions, preventing the escape of high-concentration dust in a short period of time.

[0058] In some specific embodiments of this application, the first dust collector 110 and the second dust collector 210 are equipped with automatic dust removal mechanisms. Specifically, the automatic dust removal mechanism can be a pulse jet cleaning mechanism, a reverse air cleaning mechanism, a rapping cleaning mechanism, or a combination of the above. For example, the automatic dust removal interval can be 8 to 20 minutes, such as 10 minutes, 15 minutes, or 18 minutes; the pulse jet pressure can be controlled between 0.25 MPa and 0.35 MPa, such as 0.28 MPa, 0.30 MPa, or 0.33 MPa. By removing the dust layer from the filter media surface at set intervals, the pressure difference across the filter media can be maintained within an allowable range. When the detection component detects an increase in the filter layer pressure difference, the control system can also shorten the dust removal interval or increase the jet intensity, so that the dust removal action matches the change in dust load.

[0059] In some specific embodiments of this application, the control system includes a pipeline blockage early warning module, a filter media damage alarm module, and a fault self-diagnosis module. The pipeline blockage early warning module is signal-connected to an airflow detection element and / or a pressure detection element, and is used to output a pipeline dust accumulation early warning signal when the fan frequency increases and the pipeline airflow decreases. The filter media damage alarm module is signal-connected to a dust concentration detection element, and is used to output an alarm signal indicating filter media damage or sealing failure when the dust concentration at the dust collector outlet exceeds a preset threshold and the duration exceeds a preset time. The fault self-diagnosis module is signal-connected to each detection element, and is used to distinguish and output fault types such as pipeline blockage, filter media clogging, fan malfunction, or poor ash discharge based on the correlation and change trends of the parameters.

[0060] Specifically, when the fan operating frequency increases, but the pipeline air volume decreases and the pipeline pressure increases, it is judged as pipeline blockage; when the total differential pressure of the dust collector continues to increase, and the differential pressure falls back at a rate lower than the preset value after the dust removal jet action, while the pipeline air volume decreases, it is judged as filter bag clogging; when the frequency command output by the fan inverter is inconsistent with the actual speed feedback value of the corresponding fan drive motor, and is accompanied by abnormal fluctuations in the current of the fan drive motor, it is judged as fan malfunction; when the temperature detection value in the ash hopper below the dust collector is higher than the preset temperature threshold, or the operating current of the ash discharge valve drive motor below the ash hopper is continuously lower than the preset no-load current threshold, it is judged as ash discharge not being smooth.

[0061] The pelletized iron concentrate pretreatment dust removal system disclosed in this application can ensure that the concentration of fugitive dust in the workshop is no greater than 0.8 mg / Nm³ and the dust concentration at the dust collector outlet is no greater than 10 mg / Nm³. It should be noted that the above values ​​are achievable operating indicators obtained under specific test conditions and should not be construed as limiting the scope of protection of this application. The pellet iron concentrate pretreatment dust removal system disclosed in this application operates as follows: First, after grinding and beneficiation, lean and fine iron ore is processed to obtain wet iron concentrate raw material with a moisture content exceeding 10%. The wet raw material is transported to dryer 10 for drying. During the operation of dryer 10, warm and humid dust-laden gas is generated at the feed inlet, discharge outlet, and pressure relief outlet. The first fan 120 is started, creating a negative pressure in the first dust collector 110 and the first dust removal pipeline 130. The dust-laden gas enters the first dust collector 110 through the first dust removal pipeline 130. Because the outer wall of the first dust removal pipeline 130 is equipped with a heat-tracing and insulation structure, the humid gas inside the pipeline is less likely to condense due to the decrease in pipe wall temperature during transportation, and dust is less likely to adhere and clump on the pipe wall due to moisture. Subsequently, the filter media in the first dust collector 110 intercepts the dust, and the purified gas is discharged by the first fan 120. The collected dust is returned to the material conveying pipeline of the pellet iron concentrate pretreatment system through the ash discharge port of the first dust collector 110.

[0062] The low-moisture iron concentrate, dried by dryer 10, is conveyed to buffer weighing hopper 20 for sealed temporary storage and weighing. After weighing, it is fed into high-pressure roller mill 30 at a uniform speed and in a quantitative manner. High-pressure roller mill 30 performs high-pressure extrusion and crushing on the loose, dry iron concentrate, pressing the loose powder into a dense cake, while refining the particle size and specific surface area of ​​the material, improving the overall homogeneity and pelletizing performance of the iron concentrate raw material. The dust generated during the roller pressing process in high-pressure roller mill 30 is confined within the closed enclosure by the first dust collection hood 230. The second fan 220 creates a negative pressure in the second dust removal pipeline 270, maintaining a slightly negative pressure inside the first dust collection hood 230. Because the pressure inside the hood is lower than the external ambient pressure, an air supply path from the outside to the inside is formed at the gaps in the hood, preventing the roller pressing dust from escaping outwards, but instead allowing it to enter the second dust removal pipeline 270 with the airflow. The dust generated in the conveying pipeline from dryer 10 to buffer weighing hopper 20 is collected by the fourth dust collection hood 290.

[0063] The auxiliary material silo 40 stores bentonite, binder, flux, and other auxiliary materials specifically for pelletizing. These materials are metered and quantitatively fed in real time via a bottom-mounted weighing scale, ensuring a precise ratio between the main material (iron concentrate) and the auxiliary materials, guaranteeing uniform composition and stable performance of the subsequent mixture. Second dust collection hoods 240 are installed at the discharge port of the auxiliary material silo 40, the conveying area of ​​the weighing scale 50, and the discharge port of the weighing scale 50 to capture dust-laden gases generated during material discharge and conveying. Because the air velocity at the opening of the second dust collection hood 240 matches the material discharge characteristics, the raised dust is carried into the second dust removal pipeline 270 by the collected airflow, while the iron concentrate continues to fall along the predetermined path and complete weighing and conveying.

[0064] Subsequently, the iron concentrate and auxiliary materials enter the mixer 60 for mixing. A third dust collection hood 250, installed at the top and outlet of the mixer 60, collects the dust generated during the mixing and discharging processes, respectively. The dust-laden gas enters the second dust collector 210 through the second dust removal pipeline 270. First, it passes through an inertial separation module, where coarse dust particles are separated due to inertia. Then, the gas containing fine dust enters the filtration module and is further filtered by a modified fiber composite filter layer. Because the coarse dust particles have been separated at the front end, the dust load on the filtration module is reduced, and the rate of increase in the filter layer pressure differential slows down accordingly, allowing the dust removal mechanism to operate within a more stable pressure differential range.

[0065] The dust collected by the second dust collector 210 flows back to the feed end of the mixer 60 or the material conveying pipeline of other pellet iron concentrate pretreatment systems through the ash discharge port, and re-enters the subsequent processing flow with the iron concentrate. During the above process, the detection component continuously collects dust concentration, temperature, airflow, and pressure parameters, and sends the detection signals to the control system. The control system adjusts the operating frequency of the first fan 120 and the second fan 220 according to changes in dust concentration, pipeline negative pressure, and airflow at each dust-generating point. When abnormalities occur in pipeline pressure, airflow, or dust concentration at the dust collector outlet, the control system outputs a blockage warning, filter media damage alarm, or other fault diagnosis information. Through a closed-loop control process of detection, judgment, and adjustment, the dust removal system can adjust its suction capacity and cleaning strategy according to the actual dust generation intensity, avoiding increased energy consumption due to long-term high-load operation and reducing dust escape caused by low-airflow operation.

[0066] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0067] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0068] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0069] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A dust removal system for pretreatment of iron ore pellets, used for dust removal in the pretreatment system of iron ore pellets, characterized in that, The pellet iron concentrate pretreatment system includes a dryer (10), a buffer weighing hopper (20), a high-pressure roller mill (30), an auxiliary material silo (40), a weighing scale (50), and a mixer (60). Along the material flow direction, the dryer (10), the buffer weighing hopper (20), the high-pressure roller mill (30), and the mixer (60) are arranged in sequence. The weighing scale (50) is located at the outlet of the auxiliary material silo (40) and is located upstream of the mixer (60). The dust removal system includes a first dust removal component (100) and a second dust removal component (200). The first dust removal component (100) is connected to the dust generation point of the dryer (10) through a first dust removal pipeline (130). The second dust removal component (200) is connected to the dust generation point of the high-pressure roller mill (30), the dust generation point of the auxiliary material silo (40), the dust generation point of the weighing scale (50), and the dust generation point of the mixer (60) through a second dust removal pipeline (270). The first dust removal component (100) includes a first dust collector (110), and the second dust removal component (200) includes a second dust collector (210). The ash discharge port of the first dust collector (110) and the ash discharge port of the second dust collector (210) are respectively connected to the material conveying pipeline of the pellet iron concentrate pretreatment system.

2. The pelletized iron concentrate pretreatment dust removal system as described in claim 1, characterized in that, The first dust removal assembly (100) includes a first dust collector (110) and a first fan (120). The first fan (120) is connected to the air outlet of the first dust collector (110). The dryer (10) has a feed inlet, a discharge outlet and a pressure relief outlet. The feed inlet, the discharge outlet and the pressure relief outlet are respectively connected to the first dust removal pipeline (130).

3. The pelletized iron concentrate pretreatment dust removal system as described in claim 1, characterized in that, The second dust removal assembly (200) includes the second dust collector (210) and the second fan (220). The second fan (220) is connected to the outlet of the second dust collector (210). Along the gas flow direction, the second dust collector (210) includes an inertial separation module and a filter module.

4. The pelletized iron concentrate pretreatment dust removal system as described in claim 3, characterized in that, The filtration module is a modified fiber composite filter layer.

5. The pelletized iron concentrate pretreatment dust removal system as described in claim 3, characterized in that, The second dust removal assembly (200) includes a first dust collection hood (230), which is a closed hood. The high-pressure roller mill (30) is housed inside the first dust collection hood (230). The first dust collection hood (230) is connected to the second dust removal pipeline (270), and the second dust removal pipeline (270) is connected to the second dust collector (210).

6. The pelletized iron concentrate pretreatment dust removal system as described in claim 5, characterized in that, The second dust removal component (200) includes a second dust collection hood (240). The discharge port of the auxiliary material silo (40), the conveying area of ​​the metering scale (50), and the discharge port of the metering scale (50) are respectively provided with the second dust collection hood (240). Each of the second dust collection hoods (240) is connected to the second dust removal pipeline (270).

7. The pelletized iron concentrate pretreatment dust removal system as described in claim 5, characterized in that, The second dust removal assembly (200) includes a third dust collection hood (250). The third dust collection hood (250) is provided on the top of the mixer (60) and at the discharge port of the mixer (60). The third dust collection hood (250) is connected to the second dust removal pipeline (270).

8. The pelletized iron concentrate pretreatment dust removal system according to any one of claims 1-7, characterized in that, The first dust collector (110) is a bag filter.

9. The pelletized iron concentrate pretreatment dust removal system according to any one of claims 1-8, characterized in that, The pellet iron concentrate pretreatment dust removal system includes a detection component and a control system. The detection component is set at the dust generation point of the dryer (10), the dust generation point of the high-pressure roller mill (30), the dust generation point of the auxiliary material silo (40), the dust generation point of the weighing scale (50), the dust generation point of the mixer (60), the first dust removal pipeline (130), the second dust removal pipeline (270), the first dust collector (110), and the second dust collector (210). The detection component includes at least a dust concentration detection element, a temperature detection element, a pressure detection element, and an airflow detection element, for collecting dust concentration, temperature, airflow, and pressure parameters of the dust-laden gas. The concentration detection element, the temperature detection element, the pressure detection element, and the airflow detection element are respectively connected to the control system signal.

10. The pelletized iron concentrate pretreatment dust removal system as described in claim 9, characterized in that, The first fan (120) of the first dust removal component (100) and the second fan (220) of the second dust removal component (200) are respectively connected to the control system. The control system is configured to adjust the operating frequency of the first fan and / or the second fan according to the real-time operating parameters of each dust-generating point. When the real-time operating parameters indicate an increase in dust load or insufficient suction capacity, the operating frequency of the corresponding fan should be increased. When the real-time operating parameters indicate a decrease in dust generation load and excessive suction, the operating frequency of the corresponding fan is reduced.

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