A process for the pneumatic purification of sheet minerals

Abstract

The application discloses a flaky mineral air separation purification process, which comprises the following steps: high-pressure roller grinding of raw ore, then self-grinding; adding the self-ground raw ore into an air separation device to perform rough separation, obtaining rough concentrate and rough tailings; regrinding the obtained rough tailings, then adding the regrinded rough tailings into the air separation device to perform scavenging, obtaining tailings and scavenging middlings; combining the rough concentrate and the scavenging middlings, then performing one-time regrinding and one-time cleaning, obtaining concentrate and middlings; performing several times of regrinding and cleaning on the concentrate, obtaining required concentrate products. Through the self-grinding of the material after high-pressure roller grinding and the regrinding and rolling pressure of the grinding mode, the material can be in a fully dispersed state without damaging the flaky mineral, so that the flaky mineral is effectively protected; through the air separation device, the flaky mineral and the granular gangue mineral can be effectively separated and purified.

Description

Technical Field

[0001] This invention relates to the field of mineral purification technology, specifically to a process for air separation purification of flaky minerals. Background Technology

[0002] Non-metallic minerals possess unique properties such as adsorption, thermal conductivity, heat insulation, electrical conductivity, insulation, and shielding, enabling them to be widely used in numerous industrial sectors and playing a vital role in national economic and social development. These unique properties are closely related to their structure, such as granular, flaky, fibrous, and needle-like forms. Therefore, how to improve the alcohol extraction of non-metallic minerals while protecting their structure is an important research direction for the processing and utilization of non-metallic minerals.

[0003] Platy minerals refer to minerals with a platy granular structure, such as mica, talc, vermiculite, and graphite. Due to their unique structure, dry air classification is an important method and process for purifying platy minerals. It not only preserves the platy structure of the minerals but also has a relatively simple process, does not require water, and has a wider range of applications. However, current air classification processes for platy minerals such as mica, talc, vermiculite, and graphite have the following problems:

[0004] (1) Full liberation is a prerequisite for effective sorting. However, current liberation processes such as crushing and grinding severely damage platy structures, especially minerals with large platy structures;

[0005] (2) The current dry air separation efficiency is not high, especially for large-scale minerals; the larger the platy minerals are, the greater the influence of gravity and the less the influence of wind, making it more difficult to separate them from granular gangue minerals, resulting in poor purification effect.

[0006] Therefore, a process for purifying flaky minerals by air separation is designed to ensure that the material is fully dispersed without damaging the flaky minerals. The air separation device can achieve efficient separation and purification of flaky minerals and granular gangue minerals, which has broad application prospects. Summary of the Invention

[0007] The purpose of this invention is to provide a process for air separation and purification of flaky minerals.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a process for air classification and purification of flaky minerals, comprising the following steps:

[0009] (1) The raw ore is subjected to high-pressure roller milling and then auto-grinding;

[0010] (2) The auto-grinding raw ore is added to an air classifier for roughing to obtain rough concentrate and rough tailings;

[0011] (3) The coarse tailings obtained in step (2) are regrinded and then added to the air classifier for scavenging to obtain tailings and scavenged ore;

[0012] (4) Combine the rough concentrate with the scavenged middlings obtained in step (3), and then regrind and refine them to obtain concentrate and middlings;

[0013] (5) The concentrate is subjected to several regrinding and refining operations until a concentrate product that meets the requirements is obtained.

[0014] Preferably, the specific method of self-grinding in step (1) includes: adding the raw ore that has been subjected to high-pressure roller mill into the mill without adding grinding media, and using the gravity of the ore particles in the raw ore and the mutual friction between the ore particles to fully disperse the raw material.

[0015] As mentioned above, high-pressure roller mills not only possess the advantages of roller mills, such as minimal damage to flaky minerals during crushing, but also generate numerous microcracks within the ore particles during crushing, significantly improving the grindability of the material. However, a disadvantage of high-pressure roller mills is that the crushed material tends to clump together. Auto-grinding the material after high-pressure roller milling utilizes the gravity of the ore particles in the original ore and the mutual friction between the ore particles. This not only disperses the clumps but also liberates the ore with microcracks after roller pressing, thereby achieving the most liberated state of the raw material. Furthermore, it minimizes the damage to flaky minerals, especially large flaky minerals, during the crushing process.

[0016] Preferably, in step (1), the raw ore is crushed by a jaw crusher and then subjected to high-pressure roller milling. Preferably, the crushing scheme can be adjusted according to the actual particle size of the raw ore. If the particle size of the raw ore is relatively fine, it can be directly subjected to high-pressure roller milling without jaw crushing. If the particle size of the raw ore is relatively coarse, it needs to be crushed by a jaw crusher and then subjected to high-pressure roller milling.

[0017] In the above text, when the diameter of the raw ore particles is ≤3cm, it can be directly subjected to high-pressure roller mill without jaw crushing; when the diameter of the raw ore particles is >3cm, it needs to be crushed by jaw crusher and then subjected to high-pressure roller mill.

[0018] Preferably, the regrinding in steps (3), (4) and (5) is performed by compaction grinding.

[0019] Preferably, the specific method of the grinding and crushing includes: adding at least one long rod as grinding medium into the grinding tank of the mill; when the external tank is slowly rotated by mechanical means, the grinding medium rolls in the tank, thereby producing a grinding effect of crushing on the raw material in the tank.

[0020] Preferably, the air separation device includes a feeding system and an air separation system. The feeding system is used to convey materials to the air separation system, and the air separation system is used to separate and purify flaky minerals. The air separation system includes an air separation chamber, a material system, and an exhaust system. The material system and the exhaust system are both connected to the air separation chamber. The material system includes a feed inlet and at least two discharge outlets, and the exhaust system includes an air inlet and several air outlets.

[0021] Preferably, the feeding system includes a feeding hopper, a vibrating feeder, and a feeding shaking table. The vibrating feeder is located between the feeding shaking table and the feeding hopper, and the feeding shaking table is located between the vibrating feeder and the air separation system. After passing through the vibrating feeder, the material forms a uniformly distributed material layer with a suitable thickness on the feeding shaking table.

[0022] Preferably, the feeding shaking table moves horizontally toward or away from the air classification system, while simultaneously vibrating horizontally in a direction perpendicular to its direction of movement. The feeding shaking table can adjust the material conveying speed according to the different particle sizes of the material, thereby allowing the material entering the air classification chamber to have different initial lateral velocities.

[0023] Preferably, the greater the initial lateral velocity and the greater the lateral wind force, the more beneficial it is for the air separation and purification of large particles.

[0024] Preferably, each air outlet is connected to an exhaust fan.

[0025] Preferably, the air outlet includes a horizontal air inlet and a vertical air inlet; the airflow trajectory between the horizontal air inlet and the air inlet is parallel to the horizontal plane, and the airflow trajectory at the vertical air inlet is perpendicular to the horizontal plane.

[0026] The horizontal air inlet can be adjusted to regulate the horizontal airflow inside the air separator.

[0027] The longitudinal air inlet is used to create an upward longitudinal airflow in the air separation chamber, and the airflow intensity can be adjusted at the longitudinal air inlet.

[0028] Preferably, the air classifier is used for raw material air classification and purification. The upper part of the air classifier is connected to the feed inlet and the longitudinal air inlet, the left side of the air classifier is connected to the air inlet, the right side is connected to the transverse air inlet, and the lower part is connected to the discharge outlet.

[0029] Preferably, the methods for coarse selection, sweeping selection, and fine selection all include the following steps:

[0030] S1. The feeding system conveys materials to the air separation system. During the conveying process, the feeding speed is adjusted and controlled to ensure that the materials are fully dispersed.

[0031] S2. Turn on the air intake system to create negative pressure in the air intake, and introduce the dispersed material into the air separation chamber through the feed inlet. Under the combined action of natural gravity and wind, particles of different shapes form different motion trajectories in the air separation chamber and are discharged from different outlets, thus achieving separation.

[0032] The materials after auto-grinding or regrinding include granular minerals and flaky minerals. Granular minerals are less affected by wind force and move a shorter distance laterally, and are discharged from the outlet below the feed inlet. Flaky minerals are more affected by wind force in the air classifier chamber and move a relatively longer distance laterally.

[0033] Preferably, in step S1, the material is first added to the feeding hopper, and the feeding speed is adjusted and controlled. After passing through the vibrating feeder, a uniformly distributed material layer of suitable thickness is formed on the feeding shaker, so that the material is as dispersed as possible on the feeding shaker. The feeding shaker can vibrate left and right while conveying the raw material forward, which can further disperse the material on the shaker. After passing through the vibrating feeder and the feeding shaker, the material is in a fully dispersed state and then enters the air separation system.

[0034] The smaller the flaky mineral, the greater the impact of wind, the longer the lateral movement, and the farther it is discharged from the outlet.

[0035] Preferably, in step S2, the induced draft fan is turned on to generate negative pressure in the horizontal and vertical induced draft vents, and air enters the air separation chamber from the air inlet and then exits from the horizontal and vertical induced draft vents respectively.

[0036] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0037] 1. This invention utilizes the gravity of the ore particles and the mutual friction between them to auto-grind the material after high-pressure roller milling. This grinding method not only disperses agglomerated ore particles but also dissociates micro-cracked ore after roller pressing, thus achieving the most possible dissociation state for the raw material. Moreover, the damage to flaky minerals, especially large flaky minerals, is minimized during the crushing process. The regrinding and rolling method also effectively avoids the crushing of flaky minerals by the grinding media, effectively protecting the flaky minerals and ensuring that the material is fully dispersed without damaging them.

[0038] 2. This invention uses an air separation device for air separation. The feeding shaking table in the air separation device has a left and right vibration function, which can make the material fully dispersed. At the same time, the feeding shaking table can adjust the material conveying speed according to the different particle sizes of the material, so that the material entering the air separation chamber has different lateral initial speeds, which can meet the air separation requirements of the material.

[0039] 3. This invention incorporates a longitudinal air inlet within the air separation chamber, generating an upward longitudinal airflow that provides an upward lifting force to large, flaky minerals. This overcomes the effects of gravity, increases their lateral movement distance, and thus achieves separation from granular minerals. Therefore, the opening and closing of the longitudinal air inlet and the airflow intensity can be controlled according to the particle size of the material, enabling effective separation of flaky minerals.

[0040] 4. The present invention has a simple structure and a simple method, which can effectively separate minerals and achieve good separation results, making it suitable for widespread use. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a flowchart illustrating Embodiment 1 of the invention.

[0043] Figure 2 This is a flowchart illustrating Embodiment 2 of the invention.

[0044] Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0045] Among them, 1. Feed hopper; 2. Vibrating feeder; 3. Feeding shaking table; 4-1. Air classifier chamber; 4-2. Feed inlet; 4-3. First discharge outlet; 4-4. Second discharge outlet; 4-5. Third discharge outlet; 4-6. Air inlet; 4-7. Horizontal air inlet; 4-8. Vertical air inlet. Detailed Implementation

[0046] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] like Figure 1 As shown, this embodiment relates to a process for air classification and purification of flaky minerals, including the following steps:

[0049] (1) The raw ore is subjected to high-pressure roller milling and then auto-grinding;

[0050] (2) The auto-grinding raw ore is added to an air classifier for roughing to obtain rough concentrate and rough tailings;

[0051] (3) The coarse tailings obtained in step (2) are regrinded and then added to the air classifier for scavenging to obtain tailings and scavenged ore;

[0052] (4) Combine the rough concentrate with the scavenged medium obtained in step (3), and perform a regrinding and a fine cleaning to obtain the first concentrate and the first medium.

[0053] (5) The first concentrate is regrinded and refined again to obtain a concentrate product that meets the requirements.

[0054] Furthermore, the specific method of self-grinding in step (1) includes: adding the raw ore that has been subjected to high-pressure roller mill into the mill without adding grinding media, and using the gravity of the ore particles in the raw ore and the mutual friction between the ore particles to fully disperse the raw material.

[0055] As mentioned above, high-pressure roller mills not only possess the advantages of roller mills, such as minimal damage to flaky minerals during crushing, but also generate numerous microcracks within the ore particles during crushing, significantly improving the grindability of the material. However, a disadvantage of high-pressure roller mills is that the crushed material tends to clump together. Auto-grinding the material after high-pressure roller milling utilizes the gravity of the ore particles in the original ore and the mutual friction between the ore particles. This not only disperses the clumps but also liberates the ore with microcracks after roller pressing, thereby achieving the most liberated state of the raw material. Furthermore, it minimizes the damage to flaky minerals, especially large flaky minerals, during the crushing process.

[0056] In this embodiment, in step (1), the raw ore is crushed by a jaw crusher and then subjected to a high-pressure roller mill.

[0057] In other preferred embodiments, the crushing process can be adjusted according to the actual particle size of the raw ore. For example, if the raw ore particle size is fine, it can be directly subjected to high-pressure roller milling without jaw crushing. If the raw ore particle size is coarse, it needs to be crushed by jaw crusher before high-pressure roller milling. Specifically, when the diameter of the raw ore particles is ≤3cm, it can be directly subjected to high-pressure roller milling without jaw crushing; when the diameter of the raw ore particles is >3cm, it needs to be crushed by jaw crusher before high-pressure roller milling.

[0058] Furthermore, the regrinding in steps (3), (4) and (5) is carried out by crushing grinding.

[0059] Furthermore, the specific method of the grinding and crushing process includes: adding at least one long rod as grinding medium into the grinding tank of the mill; when the external tank is rotated slowly by mechanical means, the grinding medium rolls within the tank, thereby producing a grinding and crushing effect on the raw materials within the tank.

[0060] Example 2

[0061] like Figure 2 As shown, this embodiment relates to a process for air classification and purification of flaky minerals, including the following steps:

[0062] (1) The raw ore is subjected to high-pressure roller milling and then auto-grinding;

[0063] (2) The auto-grinding raw ore is added to an air classifier for roughing to obtain rough concentrate and rough tailings;

[0064] (3) The coarse tailings obtained in step (2) are regrinded and then added to the air classifier for scavenging to obtain tailings and scavenged ore;

[0065] (4) Combine the rough concentrate with the scavenged middlings obtained in step (3), and perform a regrinding and a fine cleaning to obtain concentrate and middlings;

[0066] (5) The concentrate obtained in the previous step is regrinded and refined again to obtain the concentrate and middlings in this step;

[0067] (6) Repeat step (5) at least once until the desired concentrate product is obtained.

[0068] Example 3

[0069] This embodiment is based on the above embodiment one or two, and the similarities with the above embodiments will not be repeated.

[0070] like Figure 3 As shown, this embodiment relates to an air separation device in a process for purifying flaky minerals by air separation. The air separation device includes a feeding system and an air separation system. The feeding system is used to convey materials to the air separation system, and the air separation system is used to separate and purify flaky minerals. The air separation system includes an air separation chamber 4-1, a material system, and an exhaust system. The material system and the exhaust system are both connected to the air separation chamber. The material system includes an inlet 4-2 and at least two outlets. The exhaust system includes an air inlet 4-6 and several air outlets.

[0071] Furthermore, the feeding system includes a feeding hopper 1, a vibrating feeder 2, and a feeding shaking table 3. The vibrating feeder is located between the feeding shaking table and the feeding hopper, and the feeding shaking table is located between the vibrating feeder and the air separation system. After passing through the vibrating feeder, the material forms a uniformly distributed material layer with a suitable thickness on the feeding shaking table.

[0072] Furthermore, the feeding shaking table moves horizontally toward or away from the air classification system, while simultaneously vibrating horizontally in a direction perpendicular to its direction of movement. The feeding shaking table can adjust the material conveying speed according to the different particle sizes of the material, thereby allowing the material entering the air classification chamber to have different initial lateral velocities.

[0073] Furthermore, the greater the initial lateral velocity and the greater the lateral wind force, the more beneficial it is for the air separation and purification of large particles.

[0074] Furthermore, each air outlet is connected to an exhaust fan.

[0075] Furthermore, the air outlet includes a horizontal air inlet 4-7 and a vertical air inlet 4-8; the airflow trajectory between the horizontal air inlet and the air inlet is parallel to the horizontal plane, and the airflow trajectory at the vertical air inlet is perpendicular to the horizontal plane.

[0076] The horizontal air inlet can be adjusted to regulate the horizontal airflow inside the air separator.

[0077] The longitudinal air inlet is used to create an upward longitudinal airflow in the air separation chamber, and the airflow intensity can be adjusted at the longitudinal air inlet.

[0078] In this embodiment, the discharge port includes a first discharge port 4-3, a second discharge port 4-4, and a third discharge port 4-5; the first discharge port is located below the inlet, the third discharge port is located away from the first discharge port and close to the transverse air vent, and the second discharge port is located between the first discharge port and the third discharge port.

[0079] In other preferred embodiments, the number of discharge ports may be set to 2 or at least 4, depending on the number of mineral subcategories.

[0080] Furthermore, the air separation chamber is used for raw material air separation and purification. The upper part of the air separation chamber is connected to the feed inlet and the longitudinal air inlet. The left side of the air separation chamber is connected to the air inlet, the right side is connected to the transverse air inlet, and the lower part is connected to the discharge outlet.

[0081] Furthermore, the methods for coarse selection, sweeping selection, and fine selection all include the following steps:

[0082] S1. The feeding system conveys materials to the air separation system. During the conveying process, the feeding speed is adjusted and controlled to ensure that the materials are fully dispersed.

[0083] S2. Turn on the air intake system to create negative pressure in the air intake, and introduce the dispersed material into the air separation chamber through the feed inlet. Under the combined action of natural gravity and wind, particles of different shapes form different motion trajectories in the air separation chamber and are discharged from different outlets, thus achieving separation.

[0084] The materials after auto-grinding or regrinding include granular minerals and flaky minerals. Granular minerals are less affected by wind force and move a shorter distance laterally, and are discharged from the outlet below the feed inlet. Flaky minerals are more affected by wind force in the air classifier chamber and move a relatively longer distance laterally.

[0085] Furthermore, in step S1, the material is first added to the feeding hopper, and the feeding speed is adjusted and controlled. After passing through the vibrating feeder, it forms a uniformly distributed material layer of suitable thickness on the feeding shaker, so that the material is as dispersed as possible on the feeding shaker. The feeding shaker can vibrate left and right while conveying the raw material forward, which can further disperse the material on the shaker. After passing through the vibrating feeder and the feeding shaker, the material is in a fully dispersed state and then enters the air separation system.

[0086] The smaller the flaky mineral, the greater the impact of wind, the longer the lateral movement, and the farther it is discharged from the outlet.

[0087] Furthermore, in step S2, the exhaust fan is turned on to create negative pressure in the horizontal and vertical exhaust vents. Air enters the air separation chamber from the air inlet and then exits from the horizontal and vertical exhaust vents respectively.

[0088] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A process for air classification and purification of flaky minerals, characterized in that, Includes the following steps: (1) The raw ore is subjected to high-pressure roller milling and then auto-grinding; (2) The auto-grinding raw ore is added to an air classifier for roughing to obtain a rough concentrate and a rough tailings; (3) The coarse tailings obtained in step (2) are regrinded and then added to the air classifier for scavenging to obtain tailings and scavenged ore; (4) Combine the rough concentrate with the scavenged middlings obtained in step (3), and then regrind and refine them to obtain concentrate and middlings; (5) The concentrate is subjected to several regrinding and cleaning operations until a concentrate product that meets the requirements is obtained; The specific method of self-grinding in step (1) includes: adding the raw ore that has been subjected to high-pressure roller mill into the mill without adding grinding media, and using the gravity of the ore particles in the raw ore and the mutual friction between the ore particles to fully disperse the raw material. The regrinding in steps (3), (4) and (5) is performed by compaction grinding. The specific method of the crushing and grinding includes: adding at least one long rod as a grinding medium into the grinding tank of the mill; when the external tank is driven to rotate slowly by the machine, the grinding medium rolls in the tank, thereby producing a crushing grinding effect on the raw material in the tank. The air separation device includes a feeding system and an air separation system; the air separation system includes an air separation chamber, a material system and an exhaust system, and the exhaust system includes an air inlet and several air outlets. The air outlet includes a horizontal air inlet and a vertical air inlet; the airflow trajectory between the horizontal air inlet and the air inlet is parallel to the horizontal plane, and the airflow trajectory at the vertical air inlet is perpendicular to the horizontal plane. The horizontal air inlet can be adjusted to regulate the horizontal airflow inside the air separator. The longitudinal air inlet is used to create an upward longitudinal airflow in the air separation chamber, and the airflow intensity can be adjusted at the longitudinal air inlet.

2. The air classification and purification process for flaky minerals according to claim 1, characterized in that, In step (1), the raw ore is crushed by a jaw crusher and then subjected to a high-pressure roller mill.

3. The air classification and purification process for flaky minerals according to claim 1, characterized in that, The air separation device includes a feeding system and an air separation system. The feeding system is used to convey materials to the air separation system, and the air separation system is used to separate and purify flaky minerals. The air separation system includes an air separation chamber, a material system, and an exhaust system. The material system and the exhaust system are both connected to the air separation chamber. The material system includes a feed inlet and at least two discharge outlets. The exhaust system includes an air inlet and several air outlets. An exhaust fan is connected to each air outlet.

4. The air classification and purification process for flaky minerals according to claim 3, characterized in that, The feeding system includes a feeding hopper, a vibrating feeder, and a feeding shaking table. The vibrating feeder is located between the feeding shaking table and the feeding hopper, and the feeding shaking table is located between the vibrating feeder and the air separation system. After passing through the vibrating feeder, the material forms a uniformly distributed material layer with a suitable thickness on the feeding shaking table.

5. The air classification and purification process for flaky minerals according to claim 4, characterized in that, The feeding shaking table moves horizontally toward or away from the air classifier system, and simultaneously vibrates horizontally in a direction perpendicular to its direction of movement. The feeding shaking table can adjust the material conveying speed according to the different particle sizes of the material, so that the material entering the air classifier chamber has different initial lateral velocities.

6. The air classification and purification process for flaky minerals according to any one of claims 1-5, characterized in that, The methods for rough selection, sweep selection, and fine selection all include the following steps: S1. The feeding system conveys materials to the air separation system. During the conveying process, the feeding speed is adjusted and controlled to ensure that the materials are fully dispersed. S2. Turn on the air intake system to create negative pressure in the air intake, and introduce the dispersed material into the air separation chamber through the feed inlet. Under the combined action of natural gravity and wind, particles of different shapes form different motion trajectories in the air separation chamber and are discharged from different outlets, thus achieving separation.

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