Low-dust barite powder closed dry processing production system

Abstract

This invention relates to the field of non-metallic mineral powder processing technology, specifically a low-dust, closed-loop dry processing system for barite powder. The system comprises a raw material pretreatment unit, a selective grinding unit, a modifier quantitative dosing unit, a segmented differential pressure control module, a circulating air temperature and humidity control module, an airflow classification unit, an adaptive dust collection unit, and a finished product sealed packaging unit, all connected sequentially through a fully enclosed pipeline. This invention reduces ultrafine dust generation at the source through selective grinding, utilizes grinding mechanical force to achieve in-situ dry particle modification and reduce airborne particles, employs segmented gradient differential pressure to construct an orderly airflow organization, combines closed-loop circulating air temperature and humidity control to weaken electrostatic effects, and integrates load-adaptive pulse dust collection to improve end-of-pipe dust removal efficiency. This multi-dimensional process synergy achieves comprehensive dust control throughout the entire process. No modifications to the main equipment structure are required, making it easy to promote and apply industrially.

Description

Technical Field

[0001] This invention relates to the field of non-metallic mineral powder processing technology, specifically a closed-loop dry processing system for low-dust barite powder. Background Technology

[0002] Barite is an important non-metallic mineral resource, mainly composed of barium sulfate. It possesses characteristics such as high density, chemical stability, non-magnetic properties, and non-toxicity, and is widely used in oil and gas drilling mud weighting agents, chemical fillers, coatings, pharmaceuticals, rubber and plastics, and other fields. With the increasing demands for fineness and purity from downstream industries, dry grinding has become the mainstream process for barite powder production due to its advantages such as short process flow, low production cost, and strong adaptability.

[0003] However, existing dry processing technology for barite powder faces numerous technical bottlenecks in actual production. Firstly, dust pollution is a significant problem. Barite powder has a fine particle size, easily generating large amounts of ultrafine dust during crushing, grinding, grading, and packaging. Traditional processes rely solely on end-of-pipe baghouse dust collectors, which cannot address issues such as air leakage at equipment seals and secondary dust generation from pipe accumulation. High concentrations of fugitive dust within the workshop result in emissions at the plant boundary failing to meet the "Integrated Emission Standard for Air Pollutants" and the latest environmental control requirements. Furthermore, dust diffusion leads to material waste and increased equipment wear, raising production and maintenance costs. Secondly, over-grinding during grinding is severe. Existing processes generally use universal grinding parameters without tailoring adjustments based on the hardness differences between barite and associated impurities. This results in the generation of large amounts of useless ultrafine particles, increasing the difficulty of dust control, causing a wide product particle size distribution, low yield of qualified products, and indirectly increasing production energy consumption and raw material losses.

[0004] Third, there is an inherent contradiction between system airtightness and operating energy consumption. To suppress dust escape, existing production lines typically adopt a high negative pressure operation mode throughout the process, leading to a significant increase in system air leakage rate and fan energy consumption. At the same time, high air velocity exacerbates wear and tear on pipes and equipment, shortening equipment lifespan. On the other hand, reducing negative pressure introduces environmental risks of dust escape. It is difficult to balance these two aspects, and the industry has always lacked an effective solution that can balance airtight dust suppression and energy saving. Fourth, during dry processing, static electricity is easily generated by friction between powder and equipment walls and airflow. Fine particles are adsorbed onto the inner walls of pipes and equipment, forming material accumulation. This not only affects heat exchange efficiency but also easily causes material blockage. The cleaning process generates a large amount of secondary dust, affecting the continuous and stable operation of the system and increasing manual labor intensity and safety risks.

[0005] Currently, existing technologies for dust control in the dry processing of barite powder mostly focus on single aspects such as upgrading dust removal equipment and improving equipment sealing structures. Examples include adding multi-stage dust collectors and improving equipment sealing structures. However, these improvements are all end-of-pipe treatments or structural modifications, resulting in high costs and limited effectiveness in reducing dust generation at the source, failing to meet increasingly stringent environmental requirements. Some technologies employ wet processing to fundamentally avoid dust, but wet processes require dehydration and drying, leading to long processes, high energy consumption, and large investments. Furthermore, the moisture content of the product is difficult to control, making it unsuitable for downstream applications with strict moisture content requirements, thus limiting its application.

[0006] In summary, existing technologies have not yet formed a complete system solution for dry processing of barite powder that can simultaneously achieve dust reduction at the source, dust control during the process, and efficient dust collection, while also taking into account product quality, operating energy consumption, and system stability. The various technical means lack synergy and cannot achieve a significant improvement in overall performance, resulting in obvious technological gaps and application limitations. Summary of the Invention

[0007] To address the shortcomings of existing dry barite powder processing systems, such as high dust emissions, severe over-grinding, high energy consumption, poor system stability, and lack of synergistic effects among various technologies, this invention provides a low-dust, closed-loop dry barite powder processing system. Through the synergy of multi-dimensional process methods and control modules, dust is controlled throughout the entire process, from source to end, while simultaneously improving product quality and reducing production energy consumption. This system achieves low-dust, high-efficiency, and low-cost dry barite powder production without requiring modifications to the main equipment structure.

[0008] The technical solution adopted by the present invention to solve its technical problem is: a closed dry processing production system for low dust barite powder, including a raw material pretreatment unit, a selective grinding unit, a modifier quantitative addition unit, a segmented pressure difference control module, a circulating air temperature and humidity control module, an airflow classification unit, an adaptive dust collection unit, and a finished product closed packaging unit, which are connected in sequence through a fully closed pipeline. The raw material pretreatment unit is used to crush and screen the barite ore step by step to obtain the material to be ground with a maximum particle size of less than 5 mm and a particle size uniformity coefficient of not less than 0.7. The selective grinding unit is a fully enclosed dry ball mill filled with alumina ceramic grinding media. By adjusting the media gradation, filling rate and mill operating speed, selective dissociation grinding of barite and associated impurities is achieved. The modifier quantitative addition unit is set at the feed end of the grinding unit and is equipped with a weightless precision feeding device for continuously adding compound dry modifier into the mill, thereby achieving in-situ surface modification of barite particles by utilizing the mechanochemical action of the grinding process. The segmented differential pressure control module includes multiple variable frequency fans and electric regulating valves, which are used to divide the system into four independent pressure zones along the material flow direction, forming a directional airflow organization with a gradient decrease. The circulating air temperature and humidity control module includes heating, humidification, and dehumidification components and multiple sets of detection nodes, which are used to adjust the temperature and humidity parameters of the circulating airflow in real time, reduce the static electricity of the powder, and prevent the material from sticking to the wall. The airflow classification unit is used for particle size classification, and the coarse powder is returned to the grinding unit; the adaptive dust collection unit is equipped with a load adaptive dust removal module, which dynamically adjusts the pulse dust removal strategy according to the operating parameters. The finished product sealed packaging unit is used for the collection and packaging of finished products in a fully enclosed environment.

[0009] Specifically, in the selective grinding unit, the grinding media is alumina ceramic cylindrical media, which is mixed in three diameter specifications (large, medium, and small) at a mass ratio of 3:4:3. The media filling rate is 35% to 45% of the effective volume of the mill, and the mill operating speed is 65% to 75% of the critical speed. The critical speed is calculated according to the ball mill formula nc=42.3 / √D, where D is the inner diameter of the mill cylinder.

[0010] Specifically, the weightless feeding device of the modifier quantitative addition unit is interlocked with the mill feed; the compound dry modifier is composed of calcium stearate and fumed silica in a mass ratio of 7:3, the average particle size of the modifier is less than 1μm, and the addition amount is 0.1% to 0.5% of the mass of the material to be ground.

[0011] Specifically, the segmented differential pressure control module includes three variable frequency centrifugal fans and matching electric air volume regulating valves. The gauge pressures of the four pressure ranges along the material flow direction are as follows: feeding unit +50~+100Pa, grinding unit -800~-1200Pa, classification unit -400~-600Pa, and dust collection unit -100~-200Pa. The pressure deviation of each range is controlled within ±10%.

[0012] Specifically, the circulating air temperature and humidity control module includes a pipeline electric heating module, a micro-ultrasonic humidification module, a condensation dehumidification module, and multiple sets of detection nodes. The circulating air temperature is controlled at 25℃~45℃, and the relative humidity is controlled at 35%~55%. When the electrostatic voltage of the powder exceeds 5kV, the relative humidity is increased. When the moisture content of the material exceeds 0.5%, the temperature is increased and dehumidification is started.

[0013] Specifically, the load-adaptive dust removal module collects real-time data on the inlet and outlet pressure difference of the dust collector, the powder concentration at the graded outlet, and the product particle size. The parameter adjustment priority is: pressure difference rise rate > powder concentration > particle size distribution. When the pressure difference rise rate is ≥20Pa / h or the proportion of fine powder increases, the blowing interval is shortened and the blowing pressure is increased. When the pressure difference rise rate is ≤5Pa / h and the concentration is stable, the blowing interval is extended and the blowing pressure is reduced.

[0014] Specifically, the raw material pretreatment unit includes a jaw crusher, a cone crusher and a linear vibrating screen connected in stages, and the particle size uniformity coefficient of the material to be ground is characterized by the uniformity index of the RRB distribution model.

[0015] Specifically, the airflow classification unit is a variable frequency turbine airflow classifier with a classification accuracy index of not less than 1.2. The classified coarse powder is returned to the grinding unit for further grinding through a closed pipeline.

[0016] Specifically, the entire system adopts a closed-loop circulating air structure, with a circulating air utilization rate of no less than 90%, and only a small amount of fresh air is added to maintain the system pressure balance.

[0017] Specifically, the particle size D97 of the finished barite powder can be adjusted within the range of 10μm to 45μm, and the concentration of fugitive dust emissions at the system boundary is less than 0.5mg / m³. 3 .

[0018] The beneficial effects of this invention are: (1) Dust suppression is achieved through a synergistic process throughout the entire process, resulting in extremely low dust emissions. Selective grinding reduces the generation of ultrafine particles at the source, in-situ dry modification reduces the inherent airborne properties of the particles, segmented gradient pressure differentials create directional and orderly airflow to block the escape path, and circulating air temperature and humidity control weakens the electrostatic adsorption effect of particles. These four elements form a closed-loop synergistic system of "source dust reduction - process dust control - end-of-pipe dust collection." At the same time, the laminar airflow formed by the gradient pressure differential can avoid secondary dust generation caused by turbulence, and temperature and humidity control further enhances the dust suppression effect of the modification. The multiple effects are superimposed and synergistic. Ultimately, the concentration of fugitive dust emissions at the plant boundary can be reduced to 0.5 mg / m³. 3 The following standards are far below national environmental protection standards, thoroughly improving the production and operation environment.

[0019] (2) Improved product quality and yield. Selective grinding and in-situ modification form a core synergy: Selective grinding causes barite to dissociate along cleavage planes, generating a large number of fresh active surfaces. Combined with the surface activation effect of grinding mechanical force, the particle coating rate can be increased by more than 15% compared with in-situ modification alone, and the coating layer is more uniform and firm. The tendency of particle agglomeration is significantly reduced after modification. Combined with temperature and humidity control to eliminate electrostatic agglomeration effect, the air classification accuracy can be greatly improved, the product particle size distribution is more concentrated, and the classification accuracy index reaches more than 1.2. The yield of qualified products is increased by more than 8% compared with traditional processes. At the same time, the powder dispersibility is significantly improved, the downstream application processing performance is better, and the added value of the product is higher.

[0020] (3) Significantly reduced production energy consumption. Segmented gradient pressure control, closed-loop circulating air, and adaptive dust collection work synergistically: the gradient pressure mode replaces the traditional full-process high negative pressure, which can reduce the system air leakage rate by more than 30%, and the circulating air utilization rate exceeds 90%, greatly reducing the ineffective energy consumption of the fan; at the same time, the gradient pressure reduces the interference of external temperature and humidity, which can reduce the operating load of the temperature and humidity control module; the load adaptive dust removal dynamically adjusts the injection parameters according to the real-time load, reducing compressed air energy consumption by about 20%. Under the synergistic effect of multi-dimensional energy-saving measures, the energy consumption per ton of product is reduced by 15%~20% compared with the traditional dry process, and the energy-saving effect is significant.

[0021] (4) The system's operational stability is significantly enhanced. Closed-loop temperature and humidity control works synergistically with in-situ modification and differential pressure control: on the one hand, temperature and humidity control keeps the grinding chamber temperature stable within the applicable range of the modifier, preventing the modifier from melting and failing, while optimizing the molecular motion activity of the modifier and improving the bonding strength and stability of the coating layer; on the other hand, temperature and humidity control weakens the static electricity of the powder, and in conjunction with orderly airflow, reduces adsorption on the particle wall, thus alleviating the problem of material accumulation and blockage in the pipeline from the root. The continuous operation cycle of the system is more than twice as long as that of the traditional process, greatly reducing the frequency of downtime for cleaning, and reducing maintenance costs and labor intensity.

[0022] (5) Low modification cost and easy to promote industrialization. The core innovation of this invention focuses on process parameter matching and control module optimization. It does not require modification of the main structure of the existing production line equipment. Only a small number of detection elements and control modules need to be added to achieve the upgrade. It is compatible with most existing dry grinding production lines. The modification cycle is short, the investment cost is low, and the prospects for industrial application are broad. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is an architecture diagram of the closed-loop dry processing system for low-dust barite powder provided by the present invention. Figure 2A schematic diagram of the segmented pressure differential gradient control pressure distribution of the low-dust barite powder closed dry processing production system provided by the present invention. Figure 3 The diagram shows the closed-loop control logic for circulating air temperature and humidity in the low-dust barite powder closed-loop dry processing production system provided by this invention. Detailed Implementation

[0025] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0026] like Figures 1-3 As shown, the low-dust barite powder closed-loop dry processing production system of the present invention includes a raw material pretreatment unit, a selective grinding unit, a modifier quantitative dosing unit, a segmented differential pressure control module, a circulating air temperature and humidity control module, an airflow classification unit, an adaptive dust collection unit, and a finished product closed packaging unit, which are connected sequentially through fully enclosed pipelines. The specific structure and operation mode of each unit are as follows: Raw material pretreatment unit: The raw material pretreatment unit consists of a jaw crusher, a cone crusher, and a linear vibrating screen connected in a closed, sequential manner. The discharge port of the jaw crusher is connected to the feed port of the cone crusher via a closed chute. The discharge port of the cone crusher is connected to the feed end of the linear vibrating screen via a closed bucket elevator. The material oversizes is returned to the cone crusher for further crushing via a return chute, while the material undersizes is sent to the feed buffer bin of the grinding unit via a closed screw conveyor. The linear vibrating screen adopts a double-layer screen structure with 5mm mesh openings. The upper layer removes large impurities, while the lower layer precisely controls the maximum discharge particle size.

[0027] This unit is used to crush and screen barite ore in stages to remove oversized particles and fine mud impurities, and obtain grinding material with a maximum particle size ≤5mm and a particle size uniformity coefficient ≥0.7. This provides stable and uniform feeding conditions for subsequent selective grinding and avoids unstable grinding conditions and over-grinding caused by fluctuations in feed particle size.

[0028] Selective grinding unit: The selective grinding unit is a horizontal, fully enclosed dry ball mill. Both ends of the mill employ a combination of labyrinth seals and packing seals to ensure the grinding chamber remains completely sealed, eliminating any dust overflow channels. The mill is filled with alumina ceramic cylindrical grinding media, which combines high wear resistance with low iron contamination, preventing the introduction of iron impurities during the grinding process from affecting the product's whiteness and purity.

[0029] The grinding media are configured in three sizes: large (φ30×30mm cylinder), medium (φ20×20mm cylinder), and small (φ10×10mm cylinder), and are uniformly mixed in a mass ratio of 3:4:3. By combining different sized media, the effects of coarse particle impact crushing and fine particle grinding and dissociation are balanced. The media filling rate is controlled at 35%~45% of the effective volume of the mill, and the mill operating speed is set at 65%~75% of the critical speed.

[0030] Within this parameter range, the grinding force combines low-to-medium intensity impact with abrasive action. Utilizing the hardness difference between barite (Mohs hardness 3-3.5) and associated impurities such as quartz and calcite (Mohs hardness 5 and above), barite preferentially dissociates and breaks along cleavage planes, while high-hardness impurities are less likely to be over-ground. This significantly reduces the generation of ultrafine, useless particles and lowers the total dust production. The grinding endpoint is determined by a barite monomer liberation degree ≥90%. The liberation degree is detected offline using optical microscopy, combined with real-time monitoring of the discharge particle size using an online particle size analyzer to ensure stable grinding performance.

[0031] Modifier quantitative dosing unit: The modifier quantitative dosing unit is located at the feed end of the grinding unit and consists of a modifier storage bin, a fluidized feed device, and a loss-in-weight precision feed scale. The loss-in-weight feed scale is interlocked with the mill feed screw conveyor. When the feed rate fluctuates, the feed device synchronously adjusts the dosing rate according to the set ratio, with a response delay of ≤2s, ensuring a constant modifier dosing ratio. When the system starts, modifier dosing begins 10s before material feeding, and when the system stops, modifier dosing stops 30s after material feeding, ensuring that all material flowing through the mill can come into contact with the modifier.

[0032] The modifier is a dry modifier composed of calcium stearate and fumed silica in a mass ratio of 7:3. The modifier itself is an ultrafine powder with an average particle size of less than 1μm. It is pre-mixed evenly by a mixer and stored in a storage silo. The dosage is controlled to be 0.1% to 0.5% of the mass of the material to be ground.

[0033] The modifier enters the sealed mill along with the material. Under the intense mechanical collision and friction of the grinding process, the modifier molecules are uniformly adsorbed and coated on the surface of the barite particles through mechanochemical effects, forming a dense organic-inorganic composite coating layer. This coating layer can significantly reduce the surface energy of the barite particles, weaken the tendency of fine particles to agglomerate, and improve the classification accuracy and product yield in subsequent classification processes. Furthermore, it can alter the surface properties of the particles, reduce their aerodynamic flyability, and increase their settling velocity, thereby reducing dust suspension and diffusion at the process level. This unit does not require additional dedicated modification equipment; in-situ modification can be completed using the mechanical force of the existing grinding process, resulting in a simple process flow and low modification costs.

[0034] Segmented differential pressure control module: The segmented differential pressure control module includes three variable frequency centrifugal fans, multiple sets of split-leaf electric air volume regulating valves, and pressure sensors. The three fans are a grinding discharge fan, a classifying induced draft fan, and a dust collection induced draft fan, which are arranged sequentially in the outlet pipes of the grinding unit, the classifying unit, and the dust collection unit. One pressure detection point is set at the inlet and outlet of each pressure range, and the average value of the two points is taken as the basis for range pressure control.

[0035] The module employs a PID closed-loop control algorithm, with control parameters set to a proportional coefficient of 0.8, an integral time of 120s, and a derivative time of 30s. By adjusting the fan speed and valve opening, the pressure in each zone is independently regulated, achieving a steady-state regulation accuracy better than ±10%. Along the material and airflow direction, the entire system is divided into four independent pressure control zones: a feeding unit, a grinding unit, a classification unit, and a dust collection unit, forming a pressure field with a gradually decreasing gradient.

[0036] The specific pressure settings for each section are as follows: the feed unit is controlled at a slightly positive pressure of +50~+100Pa to prevent disorderly entry of outside air into the system, which would bring in moisture and impurities, and at the same time prevent dust from escaping backward from the feed inlet; the grinding unit is controlled at a strong negative pressure of -800~-1200Pa to provide sufficient airflow power for material conveying and grinding discharge, and to promptly carry out the fine powder generated during grinding; the classification unit is controlled at a medium negative pressure of -400~-600Pa to maintain a stable flow field within the classifier and ensure classification accuracy; and the dust collection unit is controlled at a slightly negative pressure of -100~-200Pa to reduce the face velocity of the filter bags, improve gas-solid separation efficiency, and at the same time reduce the operating load of the fan.

[0037] Each pressure zone is connected by a sealed pipeline, and with the wear-resistant rubber sealing structure of the flange, a directional and orderly airflow is formed. Dust always flows forward with the airflow, with no reverse escape path. Compared with the traditional full-process high negative pressure mode, this gradient pressure difference control method can reduce the system leakage rate by more than 30%, significantly reducing the energy consumption of the fan while ensuring the sealing and dust suppression effect.

[0038] Circulating air temperature and humidity control module: The circulating air temperature and humidity control module is installed in the system's circulating air path and includes a duct-type electric heating module, a micro-ultrasonic humidification module, a condensation dehumidification module, and temperature and humidity sensors, electrostatic sensors, and material moisture content detection points arranged at the grinding outlet, classification inlet, and dust collection inlet. The duct-type electric heating module is arranged in the circulating air return section, and its heating power is adjustable in stages; the micro-ultrasonic humidification module is arranged in the air path between the grinding outlet and the classification inlet, with an atomization frequency of 1.7MHz and an atomization particle size of 1~3μm, vaporizing into gaseous water throughout the process, with no liquid water droplets contacting the powder; the condensation dehumidification module is arranged in the circulating return air section at the dust collection outlet and adopts an air-cooled condensation structure.

[0039] The module employs PID closed-loop control logic to stably control the circulating air temperature between 25℃ and 45℃, and the relative humidity between 35% and 55%. Specifically, the control logic is as follows: when the detected powder electrostatic voltage exceeds 5kV, the system automatically activates the micro-ultrasonic humidification module. For every 1kV increase in electrostatic voltage, the relative humidity increases by 3%, up to a maximum of 55%. This increases the air moisture content to weaken the electrostatic effect of the particles, reducing material buildup and airborne particles caused by electrostatic adsorption. When the detected material moisture content exceeds 0.5%, the system automatically activates the electric heating module to increase the circulating air temperature. For every 0.1% increase in moisture content, the temperature increases by 2℃, up to a maximum of 45℃. Simultaneously, the condensation dehumidification module is activated to remove excess moisture from the circulating air. This airflow drying reduces the material moisture content, preventing particle agglomeration and adhesion to the walls, thus avoiding material blockage.

[0040] The system is equipped with an interlock protection mechanism: when the grinding chamber temperature exceeds 120℃, the circulating air volume is automatically increased and the standby duty cycle of the heating module is adjusted to ensure that the grinding chamber temperature does not exceed 130℃, which is lower than the melting point of calcium stearate (approximately 150℃), ensuring that the modifier remains in a stable solid state and preventing melting and agglomeration failure. This temperature and humidity control, in conjunction with the aforementioned in-situ modification steps, can further improve the uniformity of the modifier coating and the dust suppression effect, while ensuring long-term stable operation of the system.

[0041] Airflow classification unit and adaptive dust collection unit: The air classifying unit is a variable frequency turbine air classifier, which adjusts the speed of the classifying wheel by frequency conversion to precisely control the particle size of the product; a coarse powder return pipe is set at the bottom of the classifier, and the coarse powder returns to the mill for re-grinding under the action of centrifugal force through the closed pipe, forming a closed-loop grinding cycle.

[0042] The adaptive dust collection unit is a pulse bag dust collector. The filter bag is made of coated polyester needle-punched felt, and the filtration velocity is controlled in the range of 0.8~1.2m / min. The dust collector is equipped with a load adaptive cleaning module, which uses a PLC controller. The data acquisition frequency is 1 time / 10s, and the parameter adjustment priority is: pressure difference rise rate > powder concentration > particle size distribution.

[0043] The module collects three types of data in real time: the pressure difference between the inlet and outlet of the dust collector, the powder mass concentration at the outlet of the classifier, and the product D97 particle size. It uses multi-parameter coupled control logic to dynamically adjust the cleaning parameters. Under the baseline condition, the blowing interval is 60s and the blowing pressure is 0.4MPa. The adjustable range of the blowing interval is 30s~120s, and the adjustable range of the blowing pressure is 0.3MPa~0.6MPa. The single adjustment step is 5s and 0.05MPa, respectively.

[0044] The specific control rules are as follows: When the rate of increase of the dust collector's differential pressure is ≥20Pa / h, or the powder concentration at the stage outlet increases by more than 20%, the blowing interval is automatically shortened by 15% and the blowing pressure is increased by 0.05MPa to promptly clean the powder accumulated on the filter bag surface; when the rate of increase of the dust collector's differential pressure is ≤5Pa / h and the powder concentration fluctuation is less than 5%, the blowing interval is automatically extended by 20% and the blowing pressure is reduced by 0.05MPa to reduce compressed air consumption and secondary dust generation; when the product D97 decreases by more than 10%, i.e., the proportion of fine powder increases, the blowing interval is further shortened by 10% on the basis of the above adjustments. This adaptive control method can keep the filter bag resistance within a reasonable range, and compared with traditional timed and pressured dust removal, the dust collection efficiency is improved by more than 5%, and the compressed air energy consumption is reduced by about 20%.

[0045] Finished product sealed packaging unit: The finished product sealed packaging unit includes a sealed screw conveyor, a finished product silo, and a sealed valve-type packaging machine. The finished product powder collected by the dust collector is sent into the finished product silo via the sealed screw conveyor, and then packaged by the sealed packaging machine. The packaging station is equipped with a partial sealed hood, and the top of the sealed hood is connected to the dust collection air duct to form a slight negative pressure, preventing dust from escaping during the packaging process and realizing a fully sealed production process.

[0046] To facilitate accurate reproduction of the technical solution by those skilled in the art, the technical parameters involved in this document are uniformly defined as follows: Particle size uniformity coefficient: The uniformity index n in the Rosin-Rammler-Bennett (RRB) distribution model is used to characterize the uniformity of the particle size distribution of the material. The larger the value of n, the more concentrated the particle size distribution. Grading accuracy index: Calculated using the formula (D75 / D25)^0.5. The closer the value is to 1, the higher the grading accuracy and the narrower the particle size distribution of the product. Critical speed of the mill: Calculated according to the formula nc=42.3 / √D, where D is the inner diameter of the mill cylinder (unit: m) and nc is the critical speed (unit: r / min). Recirculating air utilization rate: The volume percentage of recirculated air volume to the total air volume handled by the system; Particle coating rate: The activation index method is used to detect the modified powder. The modified powder is placed in deionized water, stirred and allowed to stand. The percentage of floating powder mass to total powder mass is the activation index, which is used to characterize the degree of surface modification and coating of particles. System air leakage rate: Calculated using the air volume balance method, air leakage rate = (system outlet air volume - system inlet air volume) / system inlet air volume × 100%; Powder electrostatic voltage: The non-contact electrostatic voltmeter is used to dynamically detect the voltage at the center axis of the pipeline, and the average value of the test is taken for 10 consecutive minutes.

[0047] Example 1:

[0048] This embodiment describes the specific application of producing 325-mesh (D97≈45μm) general-purpose barite powder. The low-dust barite powder closed dry processing production system is configured as follows: the raw material pretreatment unit is equipped with a jaw crusher, cone crusher, and linear vibrating screen, with the equipment connected in a completely closed manner; the selective grinding unit is a closed dry ball mill with a cylinder diameter of 1.5m and a calculated critical speed of 34.5r / min; the modifier quantitative dosing unit is equipped with a loss-in-weight feed scale with an accuracy of ±0.5%, interlocked with the feed screw; the segmented differential pressure control module is equipped with three variable frequency centrifugal fans and a double-leaf electric regulating valve; the circulating air temperature and humidity control module is equipped with a pipeline electric heater, an ultrasonic humidifier, and a condensation dehumidifier; the airflow classification unit is a turbine variable frequency classifier; the adaptive dust collection unit is a pulse bag dust collector, equipped with a PLC multi-parameter adaptive dust removal module; and the finished product closed packaging unit is equipped with a closed screw conveyor and a valve-type packaging machine.

[0049] The raw material used in this embodiment is barite ore from Kaili, Guizhou Province. Testing revealed that its main component is BaSO4, with a content of 95.2%. Associated impurities are mainly quartz and calcite. The raw ore has a Mohs hardness of 3.3, and the initial particle size is 200mm~300mm. The specific operating process is as follows: The first step is raw material pretreatment: the raw ore is coarsely crushed to below 50mm using a jaw crusher, then fed into a cone crusher through a closed chute for fine crushing to below 5mm, and finally sent to a linear vibrating screen for screening via an elevator. Particles oversize are returned to the fine crushing process, while undersize material is fed into the feed buffer silo via a closed screw conveyor. Testing showed that the maximum particle size of the material to be ground was 4.8mm, the particle size uniformity coefficient calculated using the RRB model was 0.76, and the moisture content was 0.28%, meeting the feed requirements.

[0050] The second step is selective grinding operation: Alumina ceramic cylindrical grinding media are used, with three diameter specifications: large media φ30×30mm, medium media φ20×20mm, and small media φ10×10mm. These are uniformly mixed in a mass ratio of 3:4:3 and then loaded into the mill, with the media filling rate controlled at 40% of the mill's effective volume. The frequency of the mill's main motor is adjusted to achieve a mill operating speed of 24.2 r / min, which is 70% of the critical speed. The mill feed rate is set at 2 t / h, and the material is uniformly fed into the mill through a closed screw feeder. Under these parameters, the grinding force is mainly low-to-medium intensity grinding and impact, with barite minerals preferentially dissociating along cleavage planes, while high-hardness quartz impurities are less likely to be over-grinded, reducing the generation of ultrafine dust at the source. Optical microscopy analysis shows that the degree of dissociation of barite monomers in the ground product is 92.1%, meeting the dissociation requirements.

[0051] The third step is the in-situ dry modification addition: Upon system startup, the modifier feeding device is activated first, followed by the mill feed screw 10 seconds later. A compound dry modifier, composed of calcium stearate and fumed silica in a 7:3 mass ratio, is continuously added to the mill feed inlet using a loss-in-weight precision feed scale. The modifier has an average particle size of 0.75 μm and is added at 0.2% of the mass of the material to be ground. The feed rate is adjusted synchronously to compensate for fluctuations in the feed rate, with deviations controlled within ±2%. The modifier enters the mill along with the material and, under the continuous mechanical collision and friction during the grinding process, uniformly coats the surface of the barite particles through mechanochemical effects. Using the activation index method, the particle coating rate reaches 92.3%, significantly higher than the 79% achieved by the single modification process.

[0052] The fourth step is segmented differential pressure gradient control: After system startup, the segmented differential pressure control module automatically runs the PID control program, stabilizing the pressure in each section by adjusting the speed of the three fans and the valve opening: the gauge pressure of the feeding unit is stably controlled at +80Pa, with a deviation of no more than ±5Pa; the gauge pressure of the grinding unit is stably controlled at -1000Pa, with a deviation of no more than ±30Pa; the gauge pressure of the classification unit is stably controlled at -500Pa, with a deviation of no more than ±20Pa; and the gauge pressure of the dust collection unit is stably controlled at -150Pa, with a deviation of no more than ±10Pa. Seamless sealed pipes are used between each unit, and wear-resistant rubber gaskets are used to seal the flange connections. The overall air leakage rate of the system, detected using the airflow balance method, is 7.2%, far lower than the leakage rate of over 20% in traditional processes.

[0053] Step 5: Circulating air temperature and humidity control: The control benchmarks are set at 35℃ and 45% relative humidity, with an electrostatic voltage warning threshold of 5kV. During system operation, three detection nodes collect data in real time and automatically adjust: when the temperature is lower than the set value, the pipeline electric heater is activated for supplemental heating; when the relative humidity is lower than the set value, the micro-ultrasonic humidification module is activated for supplemental humidification; when the electrostatic voltage exceeds 5kV, the relative humidity is automatically increased to 50%. In this embodiment, during continuous operation, the circulating air temperature fluctuates between 33℃ and 37℃, and the relative humidity fluctuates between 42% and 48%. The highest electrostatic voltage detected by the non-contact electrostatic voltmeter is 3.2kV, which remains within a stable range; the temperature inside the grinding chamber is stable between 95℃ and 110℃, which is lower than the melting point of the modifier, indicating that the modifier is in a stable state.

[0054] Step 6, Airflow Classification and Adaptive Dust Collection: Adjust the variable frequency speed of the classifier to 1200 r / min, corresponding to a classification particle size of 325 mesh, with a calculated classification accuracy index of 1.32. Qualified fine powder enters the pulse bag filter dust collector with the airflow. The dust collector's adaptive cleaning module collects operating data every 10 seconds and adjusts parameters according to priority. In this embodiment, the initial pressure difference of the dust collector is 800 Pa. When the pressure difference rises at a rate of 22 Pa / h, the system automatically shortens the blowing interval from 60 s to 51 s and increases the blowing pressure from 0.4 MPa to 0.45 MPa. When the pressure difference falls back to 900 Pa and the rate of rise slows to 4 Pa / h, the parameters are automatically adjusted back to a blowing interval of 72 s and a blowing pressure of 0.35 MPa. During operation, the dust collector pressure difference remains stable within the range of 850~1050 Pa without significant fluctuations.

[0055] Step 7, Sealed Collection and Packaging of Finished Products: The finished powder falling from the dust collector filter bag is sent into the finished product silo by a sealed screw conveyor, and then packaged by a valve-type sealed packaging machine. The packaging station is equipped with a partial sealed cover and connected to the dust collection air duct, so there is no visible dust escaping during the packaging process.

[0056] The product and operational indicators of this embodiment were tested: the finished powder D97 was 42.8 μm, the classification accuracy index was 1.34, and the product yield was 92.3%; the concentration of fugitive dust downwind of the plant boundary was 0.32 mg / m³. 3 The power consumption per ton of product is 28.6 kWh, which is 18.2% lower than that of a traditional production line of the same scale. After the system has been running continuously for 72 hours, the inner wall of the pipe was inspected and there was no obvious powder accumulation or blockage. The system has excellent operational stability.

[0057] Example 2:

[0058] This embodiment describes the specific application of producing 1250 mesh (D97≈10μm) ultrafine barite powder. The main system configuration and raw materials are the same as in Embodiment 1. The operating parameters of each unit are optimized to meet the production requirements of ultrafine powder. The specific implementation process is as follows: The first step is raw material pretreatment: the crushing and screening process is the same as in Example 1, and the maximum particle size of the material to be ground is 4.5 mm. The particle size uniformity coefficient is calculated to be 0.78 using the RRB model, and the moisture content is 0.26%.

[0059] The second step, selective grinding operation: To meet the demands of ultrafine powder production, grinding parameters were optimized: the grinding media remained alumina ceramic cylindrical media, but the gradation was adjusted to large:medium:small = 2:4:4, increasing the proportion of small media to enhance fine grinding; the media filling rate was increased to 45%, the mill operating speed was adjusted to 25.9 r / min (75% of the critical speed), and the mill feed rate was set to 1.2 t / h. Under this parameter combination, the grinding effect was enhanced, achieving ultrafine dissociation of barite while retaining selective grinding characteristics, preventing impurities from being over-ground and mixed into the product. Testing showed that the degree of barite monomer dissociation in the ground product was 93.5%.

[0060] The third step is in-situ dry modification and addition: Due to the finer particle size and larger specific surface area of ​​the product, the amount of modifier added is increased to 0.4% of the mass of the material to be ground. The modifier ratio and material are the same as in Example 1. It is precisely added using a loss-in-weight feeder, interlocked with the feed. During the grinding process, the ultrafine particles come into full contact with the modifier, resulting in more thorough mechanochemical interaction and further improved coating uniformity, effectively inhibiting the agglomeration and dispersion of ultrafine particles. The particle coating rate was 94.1% as determined by the activation index method.

[0061] The fourth step is segmented differential pressure gradient control: Considering the tendency of ultrafine powder to become airborne, the absolute value of the negative pressure in each section is appropriately increased: the feeding unit maintains a slight positive pressure of +80Pa; the grinding unit's gauge pressure is adjusted to -1200Pa to enhance the fine powder conveying capacity; the classification unit's gauge pressure is adjusted to -600Pa to ensure a stable classification flow field; and the dust collection unit's gauge pressure is adjusted to -200Pa to increase the filter bag's filtration driving force. The pressure deviation in each section is controlled within ±8%, and the system leakage rate is measured at 8.1% using the airflow balance method.

[0062] Step 5: Temperature and humidity control of circulating air: Due to the stronger electrostatic effect of ultrafine particles, the temperature and humidity control benchmark is adjusted to 40℃ and 50% relative humidity, and the electrostatic warning threshold is lowered to 4kV. During operation, when the electrostatic voltage is detected to be close to the threshold, the humidification amount is automatically fine-tuned to maintain the relative humidity in the range of 48%~52%. At the same time, the grinding chamber temperature is monitored and controlled to not exceed 45℃ to avoid thermal decomposition of the modifier. During the operation of this embodiment, the highest electrostatic voltage of the powder was 3.5kV, and no electrostatic exceedance occurred; the temperature inside the grinding chamber was stable at 100℃~115℃, and the modifier was stable.

[0063] Step 6, Airflow Classification and Adaptive Dust Collection: The classifier speed is increased to 3200 r / min, corresponding to a classification particle size of 1250 mesh, with a calculated classification accuracy index of 1.28. In the dust collector's adaptive cleaning model, the weighting of fine powder concentration is increased. When the fine powder concentration at the classification outlet increases, the cleaning parameters are adjusted in advance to avoid filter bag clogging. During operation in this embodiment, the dust collector pressure differential is stable in the range of 950~1150 Pa. The cleaning frequency is higher than in Embodiment 1, but still lower than the traditional timed cleaning mode, and the compressed air consumption is reduced by 17%.

[0064] Step 7, sealed collection and packaging of finished products: Same as in Example 1, sealed conveying and sealed packaging are adopted, and the sealing performance of the sealed cover at the packaging station is strengthened to ensure that the ultrafine powder does not escape.

[0065] The indicators of this embodiment were tested as follows: the finished powder D97 was 9.7 μm, the classification accuracy index was 1.30, the product yield was 88.1%, and the concentration of fugitive dust at the plant boundary was 0.41 mg / m³. 3 The power consumption per ton of product is 47.3 kWh, which is 16.4% lower than that of a traditional ultrafine powder production line of the same scale. The system can run continuously for 48 hours without any material blockage. There is only a very thin layer of floating powder on the inner wall of the pipe, which does not require shutdown for cleaning.

[0066] Example 3:

[0067] This embodiment is for the processing of low-grade, high-impurity barite ore. The main system configuration is the same as in Embodiment 1. The raw material is barite ore from Hengyang, Hunan Province, with a BaSO4 content of 90.5% and high levels of associated impurities such as quartz, calcite, and clay. The hardness of the raw ore fluctuates significantly. The specific implementation process is as follows: The first step is raw material pretreatment: the crushing and screening process is the same as in Example 1, and the maximum particle size of the material to be ground is 5mm. The particle size uniformity coefficient is calculated to be 0.72 using the RRB model, and the moisture content is 0.35%. Due to the high impurity content of the raw material, an air separation process is added in the pretreatment stage to remove some of the light clay impurities and reduce the load on subsequent grinding and classification.

[0068] The second step, selective grinding operation: For high-impurity raw materials, the selective liberation effect is enhanced: the grinding media gradation is adjusted to large:medium:small = 4:3:3, increasing the proportion of large media and strengthening the impact crushing effect of coarse particles; the media filling rate is reduced to 35%, and the mill operating speed is adjusted to 22.4 r / min, which is 65% of the critical speed, reducing grinding intensity and avoiding over-crushing of high-hardness impurities. The feed rate is set to 1.8 t / h to provide sufficient liberation space for the material within the mill. Under these parameters, barite and impurities are fully liberated, and the impurity particles are generally larger than barite particles, facilitating subsequent classification and removal. Testing showed that the degree of liberation of barite was 90.8%.

[0069] The third step is in-situ dry modification and addition: the modifier dosage is 0.3% of the material mass, with the same ratio as in Example 1, and the feeding device is interlocked with the feed. Due to the high impurity content, in addition to coating the barite particles, the modifier also modifies the surface of the impurity particles, reducing the overall powder's airborne properties and improving its flowability, thus reducing material accumulation in the pipeline. Testing showed that the powder activation index was 89.6%.

[0070] The fourth step is segmented differential pressure gradient control: the pressure settings are adapted to the conveying characteristics of high impurity materials, with the feeding unit at +70Pa, the grinding unit at -900Pa, the classification unit at -450Pa, and the dust collection unit at -120Pa. The air leakage rate of the system is detected to be 7.8% using the air volume balance method.

[0071] Step 5: Temperature and humidity control of circulating air: Due to the high clay content of the raw material, it is prone to absorbing moisture and sticking to the walls. The control benchmark is adjusted to a temperature of 40℃ and a relative humidity of 40%. The temperature is appropriately increased and the humidity is reduced to prevent clay impurities from absorbing water and clumping. When the material moisture content is detected to exceed 0.6%, the heating power is automatically increased to raise the circulating air temperature to 45℃. At the same time, the condensation dehumidification module is activated to remove excess moisture and accelerate material drying. During the operation of this embodiment, the material moisture content remained stable in the range of 0.3%~0.4%, and no material sticking or clogging occurred; the temperature inside the grinding chamber remained stable in the range of 105℃~118℃.

[0072] Step 6, Airflow Classification and Adaptive Dust Collection: The classifier speed is adjusted to 1500 r / min, and the target product D97 ≈ 38 μm. Because the impurity particles are relatively coarse, they are returned to the mill along with the coarse powder during the classification process. After gradual enrichment, they can be periodically discharged, thereby improving product purity. The dust collector's adaptive cleaning mode is the same as in Example 1, and the pressure difference remains stable in the range of 800~1000 Pa during operation.

[0073] Step 7: Sealed collection and packaging of finished products: Same as in Example 1.

[0074] The indicators of this embodiment were tested: the purity of the finished powder BaSO4 was increased to 96.1%, showing a significant purification effect; D97 was 37.5 μm, the classification accuracy index was 1.27, and the product yield was 89.7%; the concentration of fugitive dust at the plant boundary was 0.35 mg / m³. 3 The power consumption per ton of product is 30.2 kWh, which is 15.8% lower than that of traditional processes; the system can run continuously for 60 hours without significant material blockage and its operation is stable.

[0075] Compare with Example 1: This comparative example uses a traditional dry processing system for barite powder. The raw materials and target product are the same as in Example 1, namely, the production of 325-mesh barite powder. The system configuration is as follows: after crushing, the raw materials are directly fed into a conventional steel ball media mill with a media filling rate of 45% and a rotational speed of 80% of the critical speed; the system uses constant negative pressure control throughout the process, with a negative pressure of -1200Pa in the grinding section; there is no in-situ modification addition unit or temperature and humidity control module; the dust collector uses timed pulse cleaning with a pulse interval of 60 seconds and a pulse pressure of 0.5MPa; and the packaging uses ordinary open-top packaging.

[0076] Testing revealed that the finished product D97 of control example 1 was 45.2 μm, with a grading accuracy index of 1.08 and a relatively wide distribution; the product yield was 81.5%; and the concentration of fugitive dust at the plant boundary was 2.87 mg / m³. 3 The power consumption per ton of product is 34.9 kWh; after 24 hours of continuous operation, the pipeline shows obvious powder accumulation, and after 48 hours, local blockage occurs, requiring shutdown for cleaning.

[0077] Compare with Example 2: This comparative example, based on the traditional process system, only upgraded the end-of-pipe dust collection equipment, adopting a high-efficiency membrane filter bag dust collector; all other conditions remained the same as in Comparative Example 1. The measured fugitive dust concentration at the plant boundary of Comparative Example 2 was 1.21 mg / m³. 3 Although there are improvements, they are still far higher than those in the embodiments of the present invention; and due to the increased resistance of the filter bag, the negative pressure of the system increases, and the power consumption per ton of product rises to 41.8 kWh, which is 19.8% higher than that of control example 1, resulting in a significant increase in energy consumption; there is no significant improvement in product yield and particle size distribution, and the problem of material accumulation and blockage in the pipeline still exists.

[0078] Compare with Example 3: This comparative example, based on the traditional process system, only adds an in-situ dry modification dosing unit. The type and amount of modifier are the same as in Example 1, and all other conditions are the same as in Comparative Example 1. The concentration of fugitive dust at the plant boundary of Comparative Example 3 was measured to be 1.53 mg / m³. 3The product yield increased to 84.2%, but dust emissions were still much higher than those in the embodiment of the present invention. Although the accumulation of dust in the pipeline was alleviated due to the lack of differential pressure gradient control and temperature and humidity regulation, the problem of electrostatic adhesion to the wall still existed, and the continuous operation time of the system was only increased to 36 hours. The particle coating rate was only 78.7%, which was much lower than 92.3% in Example 1.

[0079] Compare with Example 4: This comparative example, based on the traditional process system, adds a selective grinding unit and an in-situ modification dosing unit. The parameters are the same as in Example 1, but it lacks the segmented differential pressure control module and temperature and humidity control module. All other conditions are the same as in Comparative Example 1. Testing showed that the product yield of Comparative Example 4 increased to 87.6%, and the dust concentration at the plant boundary decreased to 1.12 mg / m³. 3 The particle coating rate is 83.5%; however, due to the lack of gradient pressure control, the system air leakage rate is as high as 19.2%, and the power consumption per ton of product is 33.7 kWh, which is only slightly reduced; moreover, the lack of temperature and humidity control leads to serious electrostatic adhesion to the walls, and the system needs to be cleaned after 38 hours of continuous operation. The overall performance is far lower than that of the embodiment of the present invention.

[0080] As can be seen from the above comparative examples, a single end-of-pipe dust removal upgrade, a single modification or improvement, or a combination of only some units cannot simultaneously achieve the comprehensive effects of low dust, high yield, low energy consumption, and high stability. This invention, through the synergistic combination of multiple technical units, produces an unexpected synergistic effect, with the improvement in various performance aspects far exceeding the simple summation of the effects of individual technical means, demonstrating significant technological progress.

[0081] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A closed-loop dry processing system for low-dust barite powder, characterized in that, It includes a raw material pretreatment unit, a selective grinding unit, a modifier quantitative addition unit, a segmented differential pressure control module, a circulating air temperature and humidity control module, an airflow classification unit, an adaptive dust collection unit, and a finished product sealed packaging unit, all connected sequentially through fully enclosed pipelines. The raw material pretreatment unit is used to crush and screen the barite ore step by step to obtain the material to be ground with a maximum particle size of less than 5 mm and a particle size uniformity coefficient of not less than 0.

7. The selective grinding unit is a fully enclosed dry ball mill filled with alumina ceramic grinding media. By adjusting the media gradation, filling rate and mill operating speed, selective dissociation grinding of barite and associated impurities is achieved. The modifier quantitative addition unit is set at the feed end of the grinding unit and is equipped with a weightless precision feeding device for continuously adding compound dry modifier into the mill, thereby achieving in-situ surface modification of barite particles by utilizing the mechanochemical action of the grinding process. The segmented differential pressure control module includes multiple variable frequency fans and electric regulating valves, which are used to divide the system into four independent pressure zones along the material flow direction, forming a directional airflow organization with a gradient decrease. The circulating air temperature and humidity control module includes heating, humidification, and dehumidification components and multiple sets of detection nodes, which are used to adjust the temperature and humidity parameters of the circulating airflow in real time, reduce the static electricity of the powder, and prevent the material from sticking to the wall. The airflow classification unit is used for particle size classification, and the coarse powder is returned to the grinding unit; the adaptive dust collection unit is equipped with a load adaptive dust removal module, which dynamically adjusts the pulse dust removal strategy according to the operating parameters. The finished product sealed packaging unit is used for the collection and packaging of finished products in a fully enclosed environment.

2. The low-dust barite powder closed-loop dry processing system according to claim 1, characterized in that: In the selective grinding unit, the grinding media are alumina ceramic cylindrical media, which are mixed in three diameter specifications (large, medium, and small) at a mass ratio of 3:4:

3. The media filling rate is 35% to 45% of the effective volume of the mill, and the mill operating speed is 65% to 75% of the critical speed. The critical speed is calculated according to the ball mill formula nc=42.3 / √D, where D is the inner diameter of the mill cylinder.

3. The low-dust barite powder closed-loop dry processing system according to claim 1, characterized in that: The weightless feeding device of the modifier quantitative addition unit is interlocked with the mill feed. The compound dry modifier is composed of calcium stearate and fumed silica in a mass ratio of 7:

3. The average particle size of the modifier is less than 1 μm, and the dosage is 0.1% to 0.5% of the mass of the material to be ground.

4. The low-dust barite powder closed-loop dry processing system according to claim 1, characterized in that: The segmented differential pressure control module includes three variable frequency centrifugal fans and matching electric air volume regulating valves. The gauge pressures of the four pressure ranges along the material flow direction are as follows: feeding unit +50~+100Pa, grinding unit -800~-1200Pa, classification unit -400~-600Pa, and dust collection unit -100~-200Pa. The pressure deviation of each range is controlled within ±10%.

5. The low-dust barite powder closed-loop dry processing system according to claim 1, characterized in that: The circulating air temperature and humidity control module includes a duct-type electric heating module, a micro-ultrasonic humidification module, a condensation dehumidification module, and multiple sets of detection nodes. The circulating air temperature is controlled at 25℃~45℃, and the relative humidity is controlled at 35%~55%. When the electrostatic voltage of the powder exceeds 5kV, increase the relative humidity; when the moisture content of the material exceeds 0.5%, increase the temperature and start dehumidification.

6. The low-dust barite powder closed-loop dry processing system according to claim 1, characterized in that: The load adaptive dust removal module collects real-time data on the inlet and outlet pressure difference of the dust collector, the powder concentration at the stage outlet, and the product particle size. The parameter adjustment priority is: pressure difference rise rate > powder concentration > particle size distribution. When the rate of increase of differential pressure is ≥20Pa / h or the proportion of fine powder increases, shorten the injection interval and increase the injection pressure; When the rate of increase in differential pressure is ≤5Pa / h and the concentration is stable, extend the injection interval and reduce the injection pressure.

7. The low-dust barite powder closed-loop dry processing system according to claim 1, characterized in that: The raw material pretreatment unit includes a jaw crusher, a cone crusher and a linear vibrating screen connected in stages. The particle size uniformity coefficient of the material to be ground is characterized by the uniformity index of the RRB distribution model.

8. The low-dust barite powder closed-loop dry processing system according to claim 1, characterized in that: The air classifying unit is a variable frequency turbine air classifier with a classification accuracy index of not less than 1.

2. The classified coarse powder is returned to the grinding unit for further grinding through a closed pipeline.

9. The low-dust barite powder closed-loop dry processing system according to claim 1, characterized in that: The entire system adopts a closed-loop air circulation structure, with a circulation air utilization rate of no less than 90%, and only a small amount of fresh air is added to maintain the system pressure balance.

10. The low-dust barite powder closed-loop dry processing system according to claim 1, characterized in that: The particle size D97 of the finished barite powder can be adjusted within the range of 10μm to 45μm, and the concentration of fugitive dust emissions at the system boundary is less than 0.5mg / m³. 3 .

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