Superfine fraction ore grading process and system

Abstract

The invention discloses a superfine fraction ore grading process and system, and the process comprises the following steps: step 1, drying and magnetic separation: drying coarse particle ore grains through a dryer, and then carrying out magnetic separation I treatment to remove magnetic impurities; the size fraction of the coarse ore grains is-30 + 150 meshes; step 2, grading pretreatment: step 1, grinding, namely grinding the dried and magnetically separated materials in a ball mill; 3, grading treatment is conducted, specifically, superfine-fraction mineral powder meeting the particle size requirement is discharged through a discharging port in the upper end of the grading machine, and coarse mineral particles not meeting the particle size requirement descend to a discharging port in the lower end of the grading machine to be discharged; the granularity is required to be-200 meshes, and the passing rate is 95%; step 4, collecting the superfine mineral powder, feeding the material discharged from a discharge port at the upper end of the classifier into a collector, and conveying the material discharged from a discharge port at the lower part of the collector to a buffer bin through a conveyor to store the superfine mineral powder; step 5, packaging the superfine mineral powder; and 6, coarse ore grain circulation is conducted, and materials discharged from a discharging opening in the lower end of the classifier are returned to the step 2 again. Through core technologies such as dry magnetic separation-grading coupling, dynamic parameter regulation and control, closed loop optimization and the like, efficient, energy-saving and clean treatment of superfine fraction ore is achieved, grading precision is greatly improved, and the-200-mesh passing rate is larger than or equal to 95%.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing, and in particular to an ultra-fine ore classification process and equipment, which are used for efficiently classifying mineral particles. Background Art

[0002] Nepheline is a feldspar-like mineral in the framework silicate. It is formed under the condition of unsaturated silicon dioxide. It is a characteristic mineral in alkaline rocks rich in sodium and poor in silicon. It is often found in alkaline volcanic rocks such as nepheline syenite, nepheline syenite, and nepheline pyroxene. Natural nepheline is similar to quartz in appearance and alkaline feldspar in properties. Its theoretical chemical composition contains 44% SiO2 and 33% A12O3. It is a mineral raw material that has been widely used in the glass and ceramic industry. The particle size of existing nepheline products is generally (-30+150 mesh), and the iron content is ≤0.30%. Compared with market demand, the iron content is relatively high and the particle size is relatively coarse, resulting in weak market competitiveness. Therefore, it is necessary to carry out deep processing of the minerals so that the product particle size reaches 200 mesh or above. In the mineral processing process, particle grading and grinding are key steps, especially for the grading of ultrafine particles. Traditional grading processes usually use a single grading equipment, which makes it difficult to achieve efficient grading effects, and the particle size control is not precise enough, resulting in unstable product quality. Existing grading equipment often has problems such as low grading efficiency, high energy consumption, and uneven product particle size distribution when processing ultrafine particles. Therefore, there is an urgent need for a process and equipment that can efficiently and accurately perform ultrafine particle grading.

[0003] Although traditional classification equipment such as hydrocyclones and inclined plate thickeners can achieve initial particle size separation, their treatment effect on fine-grained ores is limited, resulting in a large amount of useful minerals being lost with tailings, causing a waste of resources. For example, the invention patent for an inclined plate overflow slurry classification system and slurry classification process (CN105233971B) uses wet sorting, through a combination of multi-stage cyclones and inclined plate classification, which has a complex secondary sorting process and a problem of wastewater treatment due to wet sorting.

[0004] In addition, the reprocessing process of coarse particles in the existing process mostly relies on traditional grinding equipment, resulting in high energy consumption and costs. The existing invention patent, a magnetite ultra-fine crushing-classification magnetic separation method (CN105855019B), proposes to achieve ultra-fine crushing of ore through high-pressure roller mills, combined with magnetic screening and sorting to recover dissociated minerals in advance. Although it reduces the energy consumption of grinding, it involves multi-stage magnetic separation and screening, the system operation cost is high, and it is difficult to adapt to the classification requirements of high-purity ultra-fine particles.

[0005] In summary, the traditional equipment has high energy consumption for the coarse particle regrinding process, and the product classification efficiency for -200 mesh particles is insufficient. It needs to rely on multi-stage wet classification, which increases costs and environmental pollution risks, and the overall classification efficiency is low. Summary of the invention

[0006] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an ultrafine particle classification process and equipment, which can effectively solve the problems of low classification efficiency and inaccurate particle size control in the prior art, and achieve efficient and energy-saving ultrafine particle classification.

[0007] In a first aspect, the present application provides an ultra-fine ore classification process, comprising: Step 1: Drying and magnetic separation: the coarse particles are dried by a dryer and then transported to a magnetic separator I for magnetic separation to remove magnetic impurities. The coarse ore particles have a particle size of -30+150 mesh; The magnetic separation I is dry magnetic separation; Step 2: hierarchical pretreatment, the hierarchical pretreatment steps include: The first step: grinding, the material after drying and magnetic separation enters the ball mill for grinding; Step 3: Classification treatment, adjusting the primary air intake of the classifier, the material after the classification pretreatment is driven by the primary air intake, and moves at high speed from the inlet at the lower end of the classifier to the classification area along with the rising air flow, and is classified once under the strong centrifugal force generated by the high-speed rotating classification wheel in the classification area, and the ultra-fine particle-grade mineral powder that meets the particle size requirements is discharged from the discharge port at the upper end of the classifier through the blade gap of the classification wheel, and the coarse particles carry part of the fine particles and collide with them, and then fall along the wall of the classifier barrel to the coarse particle sedimentation area, and the secondary air intake is adjusted in the coarse particle sedimentation area. Under the strong washing effect of the secondary air intake, the coarse and fine particles are further separated, and the fine particles rise to the classification area for secondary classification, while the coarse ore particles that do not meet the particle size requirements fall to the discharge port at the lower end of the classifier for discharge; The particle size requirement is -200 mesh pass rate 95%; Step 4: Collecting ultrafine-grained mineral powder. The material discharged from the discharge port at the upper end of the classifier enters a collector. The ultrafine-grained mineral powder is separated and collected from the airflow by the centrifugal sedimentation principle in the collector. The material discharged from the discharge port at the lower part of the collector is conveyed to the buffer silo by a conveyor to store the ultrafine-grained mineral powder. Step 5: Ultrafine mineral powder packaging: The ultrafine mineral powder in the buffer silo is packaged in a standardized manner using a packaging machine; Step 6: The coarse ore particles are circulated, and the material discharged from the discharge port at the lower end of the classifier is returned to step 2 again.

[0008] Furthermore, the step 2 further comprises: Step 2: Magnetic separation after grinding, the ground material is transported to magnetic separator II through a conveyor for magnetic separation II; The magnetic separation II is dry magnetic separation.

[0009] Furthermore, the conveying device is a conveyor belt, and a magnetic device is arranged above the conveyor belt, and the magnetic device forms a pre-magnetic selection area above the conveyor belt through a magnetic block; the size of the pre-magnetic selection area matches the size of the conveyor belt; The magnetic block is located in the area 5-10 cm above the conveyor belt; Before the magnetic separation II, the material is passed through a pre-magnetic separation area and then through a magnetic separator II for magnetic separation II.

[0010] Furthermore, a vibration device is provided on the conveyor belt, and the vibration device allows the materials on the conveyor belt to vibrate up and down.

[0011] Furthermore, detachable baffles are provided on both sides of the conveyor belt, and a material dispersion area is formed between the conveyor belt, the baffles and the magnetic device. The material on the conveyor belt shakes up and down in the material dispersion area to prevent the material from overflowing.

[0012] Furthermore, in step 3, the classification process is controlled by adjusting the rotation speed of the classification wheel and the primary air intake volume and the secondary air intake volume; The rotation speed of the classifying wheel is 1200-1500 rpm, which increases the centrifugal force of the first classification; The primary air intake volume is 5000~6000 m³ / h to reduce the carrying of coarse particles; The secondary air volume accounts for 20% to 30% of the total air volume, which fully washes the fine powder in the coarse particles.

[0013] Furthermore, in step 4, a dust removal module is connected in series after the collector, and the dust removal module performs secondary capture on the ultrafine particle-grade mineral powder escaping from the collector. The material after secondary capture is conveyed to a buffer silo by a conveyor to store the ultrafine particle-grade mineral powder.

[0014] Furthermore, in step 5, a fully automatic packaging machine is used to isolate air and moisture through vacuum packaging or nitrogen sealing to maintain the fluidity of the powder.

[0015] Furthermore, in step 6, the material discharged from the discharge port at the lower end of the classifier is returned to step 2 again through the air chute.

[0016] On the other hand, the present application provides an ultrafine ore classification system, including: a drying and magnetic separation module, a classification pretreatment module, a classification treatment module, an ultrafine ore powder collection module, an ultrafine ore powder packaging module, and a coarse ore particle circulation module; The drying and magnetic separation module includes a dryer and a magnetic separator. The coarse ore particles are dried by the dryer and then subjected to magnetic separation by a magnetic separator to remove magnetic impurities. The coarse ore particles have a particle size of -30+150 mesh; The magnetic separator is a dry magnetic separator; The classification pretreatment module includes a ball mill; The steps of the graded pretreatment include: The first step: grinding, the material after drying and magnetic separation enters the ball mill for grinding; The grading processing module includes a classifier, and the primary air intake of the classifier is adjusted. The material after the grading pretreatment is driven by the primary air intake and moves at high speed from the inlet at the lower end of the classifier to the grading area along with the rising air flow. In the grading area, the material is classified once under the strong centrifugal force generated by the high-speed rotating grading wheel. The ultra-fine particle-grade mineral powder that meets the particle size requirements is discharged from the discharge port at the upper end of the classifier through the blade gap of the grading wheel, and the coarse particles carry part of the fine particles and collide with them, and then fall along the wall of the classifier barrel to the coarse particle sedimentation area. The secondary air intake is adjusted in the coarse particle sedimentation area. Under the strong washing effect of the secondary air intake, the coarse and fine particles are further separated, and the fine particles rise to the grading area for secondary classification, while the coarse ore particles that do not meet the particle size requirements fall to the discharge port at the lower end of the classifier for discharge; The particle size requirement is -200 mesh pass rate 95%; The ultra-fine particle size mineral powder collection module includes a collector, a conveyor, and a buffer silo; The material discharged from the discharge port at the upper end of the classifier enters the collector, where the ultrafine ore powder is separated and collected from the airflow by the centrifugal sedimentation principle, and the material discharged from the discharge port at the lower part of the collector is conveyed to the buffer silo by a conveyor to store the ultrafine ore powder; The ultra-fine-grained mineral powder packaging module includes a packaging machine, through which the ultra-fine-grained mineral powder in the buffer silo is packaged in a standardized manner; The coarse ore particle circulation module comprises a circulation device, which returns the material discharged from the discharge port at the lower end of the classifier to step 2 again.

[0017] The beneficial effects of the present invention are: (1) In order to improve the product grade, this scheme uses core technologies such as dry magnetic separation-classification coupling, dynamic parameter control, and closed-loop optimization to achieve efficient, energy-saving, and clean processing of ultra-fine ore. The classification accuracy is greatly improved, and the pass rate of -200 mesh is ≥95%.

[0018] (2) Through the use of dry magnetic separation in double stages, water consumption and pollution are reduced. After drying, magnetic separation I performs dry magnetic separation on coarse particles (-30+150 mesh) to remove magnetic impurities (such as iron filings and magnetite residues) in advance to avoid wear of subsequent grinding equipment; magnetic separation II (after grinding) combines the conveyor belt pre-magnetic separation area and the vibration device to effectively separate the newly generated magnetic impurities after grinding through the pre-magnetic separation area and material dispersion, and the magnetic content of the concentrate is reduced to less than 0.5%, reducing the subsequent sorting load. This solution replaces the traditional wet process with dry magnetic separation throughout the process, reducing water resource consumption by more than 90% and eliminating wastewater discharge problems.

[0019] (3) Closed-loop circulation and air chute work together to reduce energy consumption. The coarse particle return material is fluidized and transported through the air chute. Compared with the screw conveyor, the energy consumption is greatly reduced. The closed-loop design of the grading system reduces the circulation load to below 150%, and the unit energy consumption of the ball mill is reduced by 20% to 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0021] Figure 1 The figure is a process flow chart of ultra-fine ore classification.

[0022] Figure 2 A process flow chart of ultrafine ore classification is provided for another embodiment.

[0023] Figure 3 The figure is a block diagram of the composition of an ultra-fine ore classification system.

[0024] Figure 4 This is a diagram of the device composition of an ultra-fine ore classification system.

[0025] In the figure: 1-drying machine; 2-magnetic separator I; 3-ball mill; 4-classifier; 5-collector, 6-conveyor, 7-buffer silo; 8-packaging machine; 9-circulation device. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0027] like Figure 1 , Figure 4 As shown, an embodiment of the present invention provides an ultra-fine ore classification process, comprising the following steps: Step 1: Drying and magnetic separation: the coarse particles are dried by the dryer 1 and then transported to the magnetic separator I2 for magnetic separation I to remove magnetic impurities; The particle size of coarse ore particles is -30+150 mesh; magnetic separation I is dry magnetic separation.

[0028] In this embodiment, the coarse-grained mineral particles with a particle size of -30+150 mesh are first dried by a direct single-drum rotary dryer and then subjected to magnetic separation I. After drying, the material passes through a dry magnetic separator (magnetic field strength ≥1.2T) to separate magnetic impurities such as iron filings and mechanical wear debris in advance (removal rate > 95%), thereby effectively reducing the magnetic impurity content of the coarse-grained mineral particles.

[0029] Step 2: hierarchical pretreatment. The steps of hierarchical pretreatment include: The first step: grinding, the material after drying and magnetic separation enters the ball mill 3 for grinding.

[0030] Step 3: Classification treatment, adjust the primary air intake of the classifier 4. Driven by the primary air intake, the material after classification pretreatment moves from the inlet at the lower end of the classifier 4 to the classification area with the rising air flow at high speed. In the classification area, the material is classified once under the strong centrifugal force generated by the high-speed rotating classification wheel. The ultra-fine particle-grade mineral powder that meets the particle size requirements is discharged from the discharge port at the upper end of the classifier 4 through the blade gap of the classification wheel, and the coarse particles carry some fine particles and collide with them, and then fall along the wall of the classifier 4 to the coarse particle sedimentation area. In the coarse particle sedimentation area, adjust the secondary air intake. Under the strong washing effect of the secondary air intake, the coarse and fine particles are further separated, and the fine particles rise to the classification area for secondary classification, while the coarse ore particles that do not meet the particle size requirements fall to the discharge port at the lower end of the classifier 4 for discharge; the particle size requirement is -200 mesh pass rate 95%.

[0031] Step 4: Collecting ultrafine-grained mineral powder. The material discharged from the discharge port at the upper end of the classifier 4 enters the collector 5. The ultrafine-grained mineral powder is separated and collected from the airflow by the centrifugal sedimentation principle in the collector 5. The material discharged from the discharge port at the lower part of the collector 5 is conveyed to the buffer silo 7 through the conveyor 6 for storage of the ultrafine-grained mineral powder.

[0032] Step 5: ultra-fine-grained mineral powder packaging, the ultra-fine-grained mineral powder in the buffer silo is standardizedly packaged by the packaging machine 8.

[0033] Step 6: The coarse ore particles are circulated, and the material discharged from the discharge port at the lower end of the classifier 4 returns to step 2 again.

[0034] like Figure 2 As shown in the figure, the coarse-grained ore particles of -30+150 mesh are dried and magnetically separated in turn, and then further refined by grading pretreatment. The refined materials are graded by the classifier to obtain ultrafine ore powder that meets the particle size requirements and coarse ore particles that do not meet the particle size requirements. The two products are subsequently processed through two different processes. The processing flow of the ultrafine ore powder that meets the particle size requirements is shown by the blue process line in the figure, and the processing flow of the coarse ore particles that do not meet the particle size requirements is shown by the red process line in the figure.

[0035] The ultra-fine ore powder that meets the particle size requirements proceeds to the next step 4, and the coarse ore particles that do not meet the particle size requirements are fed back to step 2 through step 6.

[0036] In this embodiment, the coarse-grained ore particles (-30+150 mesh) are sequentially subjected to drying (dryer 1) and magnetic separation (magnetic separator I), classification pretreatment (ball mill 3), classification treatment (classifier 4), ultrafine-grained ore powder collection (collector 5, conveyor 6, buffer silo 7), ultrafine-grained ore powder packaging (packaging machine 8), and coarse ore particle circulation (circulation device 9) to achieve classification treatment of coarse-grained ore particles (-30+150 mesh). In order to improve the product grade, this scheme uses core technologies such as dry magnetic separation-classification coupling, dynamic parameter control, and closed-loop cycle optimization to achieve efficient, energy-saving, and clean processing of ultrafine-grained ores, and the classification accuracy is greatly improved, with a -200-mesh pass rate ≥95%.

[0037] Step 2 is classification pretreatment. Grinding can further refine the coarse particles. The refined coarse particles release impurities due to the degranulation operation. In order to improve the purity of the product, Figure 2 As shown, step 2 also includes: Step 2: Magnetic separation after grinding. The ground material is transported to magnetic separator II through a conveyor for magnetic separation II; Magnetic separation II is dry magnetic separation.

[0038] Through the use of dry magnetic separation in double stages, water consumption and pollution are reduced. Magnetic separation I performs dry magnetic separation on coarse particles (-30+150 mesh) after drying to remove magnetic impurities (such as iron filings and magnetite residues) in advance to avoid wear of subsequent grinding equipment; Magnetic separation II (after grinding), combined with the conveyor belt pre-magnetic separation area and the vibration device, effectively separates the newly formed magnetic impurities after grinding through the pre-magnetic separation area and material dispersion, and reduces the magnetic content of the concentrate to less than 0.5%, reducing the subsequent sorting load. In this embodiment, dry magnetic separation replaces the traditional wet process throughout the process, reducing water resource consumption by more than 90%, and there is no wastewater discharge problem.

[0039] In the second step, the ground material is transported to the magnetic separator II through a conveying device for magnetic separation II. In order to further improve the impurity removal efficiency, this embodiment performs preliminary screening of the material during the conveying process of the ground material.

[0040] Screw conveyors, belt conveyors, etc. are common conveying devices. Screw conveyors are suitable for particles <30 mm, and belt conveyors have no strict restrictions. In this embodiment, the material particle size is <30 mm, and the conveying distance is short. Considering the conveying cost, in this embodiment, the conveying device is a conveyor belt, and a magnetic device is arranged above the conveyor belt. The magnetic device forms a pre-magnetic selection zone above the conveyor belt through a magnetic block; the size of the pre-magnetic selection zone matches the size of the conveyor belt.

[0041] The material can be initially cleaned of impurities during the conveying process. The magnetic block is located above the conveyor belt. If the magnetic block is far away from the conveyor belt, the impurity removal ability is low. If the magnetic block is close to the conveyor belt, material transportation will be hindered. In this embodiment, the magnetic block is located in the area 5-10 cm above the conveyor belt. Before magnetic separation II, the material passes through the pre-magnetic separation area and then passes through the magnetic separator II for magnetic separation II.

[0042] In order to further improve the efficiency of impurity removal, a vibration device is installed on the conveyor belt, which allows the materials on the conveyor belt to shake up and down.

[0043] In this embodiment, the vibration on the conveyor belt causes the material to be monolayered (coverage ≤ 80%), the magnetic particles are fully exposed to the magnetic field of the pre-magnetic separation area, and the removal rate of non-magnetic impurities is increased to more than 98%. On the other hand, the vibration of the device destroys the van der Waals force and capillary force between the particles, the agglomeration rate is reduced by 70% to 90%, and the thickness of the loosened material layer is uniform (thickness difference <10%), thereby improving the subsequent magnetic separation II efficiency by 15% to 20%.

[0044] The traditional conveyor belt is open or semi-closed and has a vibration device, which results in a large amount of dust and serious material loss. In this embodiment, detachable baffles are provided on both sides of the conveyor belt to form a material dispersion zone between the conveyor belt, the baffle and the magnetic device. The material on the conveyor belt shakes up and down in the material dispersion zone to prevent the material from overflowing.

[0045] In step 3, the classification process is controlled by adjusting the rotation speed of the classification wheel and the primary air intake volume and the secondary air intake volume.

[0046] The classifying wheel is the core component of the classifier 4. Its rotation speed directly affects the strength of the centrifugal field and determines whether the particles can pass through the gap between the blades of the classifying wheel and enter the fine particle collection system.

[0047] The primary air intake is the power source that drives the material to rise to the classification area, which directly affects the airflow drag and particle suspension state.

[0048] The secondary air volume acts on the coarse particle settling area, separating the entrained fine particles through elutriation and optimizing the classification efficiency.

[0049] Specifically, the classifier 4 controls the centrifugal separation accuracy through the speed of the classifying wheel, the primary air intake adjusts the particle conveying capacity, and the secondary air intake optimizes the separation efficiency of coarse and fine particles. The three work together to form a dynamic balance. Through the fine adjustment of the parameter combination, continuous classification from coarse particles (-30+150 mesh) to ultrafine particles (-200 mesh) can be accurately achieved to meet the particle size requirements of different mineral processing stages, while reducing energy consumption and over-grinding risks.

[0050] In order to achieve precise control of particle size, it is necessary to comprehensively adjust the classifying wheel speed, primary air intake and secondary air intake. For high-fineness products that meet the particle size requirements (-200 mesh ≥ 95%), the control strategy is: The speed of the classifying wheel is 1200~1500rpm, which increases the centrifugal force of the first classification; The primary air volume is 5000~6000 m³ / h, which reduces the carrying of coarse particles; The secondary air intake accounts for 20% to 30% of the total air volume, which can fully wash the fine powder from the coarse particles.

[0051] For medium-fine products (-200 mesh ≈ 80%), the control strategy is: Moderately reduce the speed of the classifying wheel to 800~1000 rpm; Increase the primary air volume to 7000~8000 m³ / h to allow some coarse particles to pass through; Reduce the secondary air intake to 10% to 15% of the total air volume to reduce energy consumption.

[0052] In order to reduce energy consumption and improve classification efficiency, this embodiment adopts dynamic balance adjustment technology. Specifically, frequency conversion control technology is used to real-time link the classifying wheel motor and the primary air intake and secondary air intake control modules. For example, when the feed particle size fluctuates, the classifying wheel speed and the primary air intake and secondary air intake are automatically compensated; the adjustment parameters are fed back through an online particle size analyzer (such as a laser particle size analyzer).

[0053] Step 4 is the collection of ultrafine particle-grade mineral powder. In this step, material collection is achieved through the collector 5. In this embodiment, a cyclone collector is used to collect material. If the draft fan has too strong a suction force or the collector is not designed properly (such as the cyclone barrel has a large diameter), fine particles may not be effectively captured.

[0054] In order to improve the material collection rate, in this embodiment, in step 4, a dust removal module is connected in series after the collector 5, and the dust removal module performs secondary capture of the ultrafine particle-grade mineral powder escaping from the collector. The material after secondary capture is conveyed to the buffer silo 7 through the conveyor 6 for storage of the ultrafine particle-grade mineral powder.

[0055] Step 5 packages the materials in the buffer silo 7. In the ultra-fine ore sorting process, the packaging machine 8, as the terminal equipment of the production process, plays a key role in the standardized packaging of finished products (such as ultra-fine ore powder, magnetic separation concentrate, etc.). Its core function is not only simple material packaging, but also ensures product quality stability and transportation safety through automation, sealing and environmental control.

[0056] In this embodiment, a fully automatic packaging machine is used in step 5 to isolate air and moisture through vacuum packaging or nitrogen sealing to maintain the fluidity of the powder.

[0057] Ultrafine ore (such as -200 mesh) has a large specific surface area and is easy to absorb moisture, agglomerate or oxidize and deteriorate. The packaging machine uses vacuum packaging or nitrogen sealing to isolate air and moisture and maintain powder fluidity and chemical stability.

[0058] Particle size maintenance: Use a flexible feeding system (such as screw conveying + vibration mixing) to avoid secondary crushing or agglomeration of particles due to mechanical extrusion during the packaging process, ensuring that the products leaving the factory meet the nominal particle size (such as -200 mesh pass rate 95%).

[0059] Quantitative weighing: Through high-precision sensors (error ≤ 0.5%), fast packaging of specifications such as 25kg / bag and 1 ton / big bag can be achieved, matching the production capacity of the upstream grading system (such as processing 10 to 20 tons per hour).

[0060] Continuous operation: The dual-station or rotary packaging head design is adopted to achieve seamless bag change, avoid production line interruption due to bag change, and improve the overall process continuity.

[0061] Linked with the collection system: The feeding port of the packaging machine is directly connected to the discharge valve of the cyclone collector or dust collector, and dust-free connection is achieved through pneumatic conveying or gravity feeding, reducing material loss in the intermediate transfer link (loss rate <0.1%).

[0062] Data intercommunication: Integrated PLC control system, real-time reception of production and particle size data from upstream equipment, dynamic adjustment of packaging parameters (such as sealing temperature, filling speed) to adapt to the characteristics of different batches of products.

[0063] In an ultrafine ore classification process, coarse ore particles that do not meet the particle size requirements are discharged through the discharge port at the lower end of the classifier 4. In order to recycle this part of the coarse ore particles, in this embodiment, in step 6, the material discharged from the discharge port at the lower end of the classifier is returned to step 2 again through the air chute.

[0064] In this embodiment, the air chute fluidizes the material through low-pressure airflow to achieve efficient and low-energy continuous transportation, and is used for horizontal or slightly inclined transportation of the material discharged from the discharge port at the lower end of the classifier. The material is transported to step 2, so that the coarse particles are further sorted through classification pretreatment, classification treatment, ultrafine particle size mineral powder collection, ultrafine particle size mineral powder packaging, and coarse ore particle circulation. The closed-loop circulation and the air chute work together to reduce energy consumption. The coarse particle return material is fluidized and transported through the air chute. Compared with the screw conveyor, the energy consumption is greatly reduced. The closed-loop design of the classification system reduces the circulation load to below 150%, and the unit energy consumption of the ball mill is reduced by 20% to 30%.

[0065] On the other hand, the present application provides an ultra-fine ore classification system, such as Figure 3 As shown, it includes: drying and magnetic separation module, classification pretreatment module, classification treatment module, ultrafine particle size ore powder collection module, ultrafine particle size ore powder packaging module, and coarse particle size circulation module; Specifically, each module device is as follows Figure 4 As shown, the drying and magnetic separation module includes a dryer 1 and a magnetic separator 12. The coarse ore particles are dried by the dryer 1 and then subjected to magnetic separation 1 by the magnetic separator 12 to remove magnetic impurities. The particle size of coarse ore particles is -30+150 mesh; Magnetic separator I is a dry magnetic separator; The classification pretreatment module includes a ball mill 3; The steps of graded pretreatment include: Step 1: Grinding: the material after drying and magnetic separation enters the ball mill 3 for grinding; The grading processing module includes a classifier 4, and the primary air intake of the classifier 4 is adjusted. Under the drive of the primary air intake, the material after grading pretreatment moves at high speed from the inlet at the lower end of the classifier 4 to the grading area along with the rising air flow. In the grading area, the material is graded once under the strong centrifugal force generated by the high-speed rotating grading wheel. The ultra-fine particle-grade mineral powder that meets the particle size requirements is discharged from the discharge port at the upper end of the classifier 4 through the blade gap of the grading wheel, and the coarse particles carry part of the fine particles and collide with them, and then fall along the wall of the classifier 4 to the coarse particle sedimentation area. In the coarse particle sedimentation area, the secondary air intake is adjusted. Under the strong washing effect of the secondary air intake, the coarse and fine particles are further separated, and the fine particles rise to the grading area for secondary classification, while the coarse ore particles that do not meet the particle size requirements fall to the discharge port at the lower end of the classifier 4 for discharge; The particle size requirement is -200 mesh with a pass rate of 95%; The ultra-fine particle size mineral powder collection module includes a collector 5, a conveyor 6, and a buffer silo 7; The material discharged from the discharge port at the upper end of the classifier 4 enters the collector 5, where the ultrafine ore powder is separated and collected from the airflow by the centrifugal sedimentation principle. The material discharged from the discharge port at the lower part of the collector 5 is conveyed to the buffer silo 7 by the conveyor 6 for storage of the ultrafine ore powder. The ultra-fine-grained mineral powder packaging module includes a packaging machine 8, through which the ultra-fine-grained mineral powder in the buffer silo is packaged in a standardized manner; The coarse ore particle circulation module includes a circulation device 9, which returns the material discharged from the discharge port at the lower end of the classifier 4 to step 2 again.

[0066] In order to improve the product grade, this system adopts core technologies such as dry magnetic separation-classification coupling, dynamic parameter control, and closed-loop optimization to achieve efficient, energy-saving, and clean processing of ultra-fine ore. The classification accuracy is greatly improved, and the pass rate of -200 mesh is ≥95%.

[0067] Magnetic separation I After drying, the coarse particles (-30+150 mesh) are subjected to dry magnetic separation to remove magnetic impurities (such as iron filings and magnetite residues) in advance to avoid wear of subsequent grinding equipment; under the action of the fan suction force, the material moves from the lower end inlet of the classifier to the classification area with the rising air flow at high speed. Under the strong centrifugal force generated by the high-speed rotating classification turbine, the material is separated, and the fine particles that meet the particle size requirements (-200 mesh pass rate 95%) enter the cyclone collection system through the gap between the classifying wheel blades. The coarse particles carry some fine particles and disappear after collision, and fall along the cylinder wall to the secondary air outlet. After the strong washing effect of the secondary air, the coarse and fine particles are separated, the fine particles rise to the classification area for secondary classification, and the coarse particles fall to the discharge port and are discharged to the air chute to enter the ball mill for grinding again. Closed-loop circulation and air chute work together to reduce energy consumption. The coarse particle return material is fluidized and transported through the air chute. Compared with the screw conveyor, the energy consumption is greatly reduced. The closed-loop design of the grading system reduces the circulation load to below 150%, and the unit energy consumption of the ball mill is reduced by 20%~30%.

[0068] The above embodiments are preferred implementation schemes of the present invention. Without departing from the inventive concept of the present invention, any obvious replacements are within the protection scope of the present invention.

Claims

1. A superfine ore classification process, characterized in that: include: Step 1: Drying and magnetic separation: the coarse particles are dried by a dryer and then transported to a magnetic separator I for magnetic separation to remove magnetic impurities. The coarse ore particles have a particle size of -30+150 mesh; The magnetic separation I is dry magnetic separation; Step 2: hierarchical pretreatment, the hierarchical pretreatment steps include: The first step: grinding, the material after drying and magnetic separation enters the ball mill for grinding; Step 3: Classification treatment, adjusting the primary air intake of the classifier, the material after the classification pretreatment is driven by the primary air intake, and moves at high speed from the inlet at the lower end of the classifier to the classification area along with the rising air flow, and is classified once under the strong centrifugal force generated by the high-speed rotating classification wheel in the classification area, and the ultra-fine particle-grade mineral powder that meets the particle size requirements is discharged from the discharge port at the upper end of the classifier through the blade gap of the classification wheel, and the coarse particles carry part of the fine particles and collide with them, and then fall along the wall of the classifier barrel to the coarse particle sedimentation area, and the secondary air intake is adjusted in the coarse particle sedimentation area. Under the strong washing effect of the secondary air intake, the coarse and fine particles are further separated, and the fine particles rise to the classification area for secondary classification, while the coarse ore particles that do not meet the particle size requirements fall to the discharge port at the lower end of the classifier for discharge; The particle size requirement is -200 mesh pass rate 95%; Step 4: Collecting ultrafine-grained mineral powder. The material discharged from the discharge port at the upper end of the classifier enters a collector. The ultrafine-grained mineral powder is separated and collected from the airflow by the centrifugal sedimentation principle in the collector. The material discharged from the discharge port at the lower part of the collector is conveyed to the buffer silo by a conveyor to store the ultrafine-grained mineral powder. Step 5: Ultrafine mineral powder packaging: The ultrafine mineral powder in the buffer silo is packaged in a standardized manner using a packaging machine; Step 6: The coarse ore particles are circulated, and the material discharged from the discharge port at the lower end of the classifier is returned to step 2 again.

2. The ultra-fine ore classification process according to claim 1, characterized in that: The step 2 also includes: Step 2: Magnetic separation after grinding, the ground material is transported to magnetic separator II through a conveyor for magnetic separation II; The magnetic separation II is dry magnetic separation.

3. The ultra-fine ore classification process according to claim 2, characterized in that: The conveying device is a conveyor belt, and a magnetic device is arranged above the conveyor belt. The magnetic device forms a pre-magnetic selection area above the conveyor belt through a magnetic block; the size of the pre-magnetic selection area matches the size of the conveyor belt; The magnetic block is located in a region 5-10 cm above the conveyor belt.

4. The ultra-fine ore classification process according to claim 3, characterized in that: The conveyor belt is provided with a vibration device, and the vibration device enables the materials on the conveyor belt to shake up and down.

5. The ultra-fine ore classification process according to claim 4, characterized in that: Detachable baffles are arranged on both sides of the conveyor belt, and a material dispersion area is formed between the conveyor belt, the baffles and the magnetic device. The material on the conveyor belt shakes up and down in the material dispersion area to prevent the material from overflowing.

6. The ultra-fine ore classification process according to claim 1, characterized in that: In step 3, the classification process is controlled by adjusting the rotation speed of the classification wheel and the primary air intake volume and the secondary air intake volume; The rotation speed of the classifying wheel is 1200-1500 rpm, which increases the centrifugal force of the first classification; The primary air intake volume is 5000~6000 m³ / h to reduce the carrying of coarse particles; The secondary air volume accounts for 20% to 30% of the total air volume, which fully washes the fine powder in the coarse particles.

7. The ultra-fine ore classification process according to claim 1, characterized in that: In step 4, a dust removal module is connected in series after the collector, and the dust removal module performs secondary capture on the ultrafine-grained mineral powder escaping from the collector. The material after secondary capture is conveyed to a buffer silo by a conveyor to store the ultrafine-grained mineral powder.

8. The ultra-fine ore classification process according to claim 1, characterized in that: In step 5, a fully automatic packaging machine is used to isolate air and moisture through vacuum packaging or nitrogen sealing to maintain the fluidity of the powder.

9. The ultra-fine ore classification process according to claim 1, characterized in that: In step 6, the material discharged from the discharge port at the lower end of the classifier is returned to step 2 again through the air chute.

10. An ultra-fine ore classification system, comprising: Drying and magnetic separation module, classification pretreatment module, classification treatment module, ultrafine particle size ore powder collection module, ultrafine particle size ore powder packaging module, coarse particle size circulation module; The drying and magnetic separation module includes a dryer and a magnetic separator. The coarse ore particles are dried by the dryer and then subjected to magnetic separation by a magnetic separator to remove magnetic impurities. The coarse ore particles have a particle size of -30+150 mesh; The magnetic separator is a dry magnetic separator; The classification pretreatment module includes a ball mill; The steps of the graded pretreatment include: The first step: grinding, the material after drying and magnetic separation enters the ball mill for grinding; The grading processing module includes a classifier, and the primary air intake of the classifier is adjusted. The material after the grading pretreatment is driven by the primary air intake and moves at high speed from the inlet at the lower end of the classifier to the grading area along with the rising air flow. In the grading area, the material is classified once under the strong centrifugal force generated by the high-speed rotating grading wheel. The ultra-fine particle-grade mineral powder that meets the particle size requirements is discharged from the discharge port at the upper end of the classifier through the blade gap of the grading wheel, and the coarse particles carry part of the fine particles and collide with them, and then fall along the wall of the classifier barrel to the coarse particle sedimentation area. The secondary air intake is adjusted in the coarse particle sedimentation area. Under the strong washing effect of the secondary air intake, the coarse and fine particles are further separated, and the fine particles rise to the grading area for secondary classification, while the coarse ore particles that do not meet the particle size requirements fall to the discharge port at the lower end of the classifier for discharge; The particle size requirement is -200 mesh pass rate 95%; The ultra-fine particle size mineral powder collection module includes a collector, a conveyor, and a buffer silo; The material discharged from the discharge port at the upper end of the classifier enters the collector, where the ultrafine ore powder is separated and collected from the airflow by the centrifugal sedimentation principle, and the material discharged from the discharge port at the lower part of the collector is conveyed to the buffer silo by a conveyor to store the ultrafine ore powder; The ultra-fine-grained mineral powder packaging module includes a packaging machine, through which the ultra-fine-grained mineral powder in the buffer silo is packaged in a standardized manner; The coarse ore particle circulation module comprises a circulation device, which returns the material discharged from the discharge port at the lower end of the classifier to step 2 again.

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