A device for improving the grade of phosphate ore flotation products by multi-stage gradient separation

Abstract

The utility model discloses a kind of multistage gradient sorting device of promoting phosphate rock flotation grade, for the efficient sorting of phosphate rock in phosphate fertilizer production. In view of the problems such as low multistage sorting efficiency, foam easy to block, flow regulation lag of traditional flotation equipment, the flotation tank is separated into roughing tank and cleaning tank by partition, and integration stirring, flow regulation, scraper and flushing component. Realize "roughing-cleaning" gradient sorting, dynamically control pulp / foam flow, anti-blocking design guarantee foam delivery, strengthen bubble-pulp contact. Significantly improve concentrate P2O5 grade, guarantee production continuity, improve phosphorus resource utilization, adapt to the demand of large-scale production of phosphate fertilizer.

Description

Technical Field

[0001] This utility model relates to the technical field of phosphate rock flotation equipment, and in particular to a device for multi-stage gradient separation to improve the flotation grade of phosphate rock. Background Technology

[0002] Phosphate fertilizer is a core agricultural input for ensuring global food security, and its main raw material is phosphate rock. In the production process of phosphate fertilizers (such as monoammonium phosphate, diammonium phosphate, and superphosphate), flotation enrichment of phosphate rock is a crucial step—removing gangue minerals (such as quartz, calcite, and dolomite) and harmful impurities (such as iron and aluminum oxides) from the phosphate rock through flotation to obtain high-grade phosphate concentrate, meeting the high raw material requirements of subsequent wet-process or thermal-process phosphoric acid production. However, the current phosphate rock flotation technology and equipment used in phosphate fertilizer production still have the following prominent problems, restricting the yield, quality, and economic efficiency of phosphate fertilizer production: 1. Insufficient multi-stage separation accuracy, making it difficult to meet the requirements of phosphate fertilizer: Traditional flotation equipment is mostly a single-stage or simple series structure, with short residence time of the slurry in a single tank, limiting the contact opportunities between bubbles and mineral particles. For low-grade phosphate rock, a single flotation cell is insufficient to achieve gradient enrichment from roughing to cleaning, resulting in a final concentrate with low P2O5 content and high impurity content, making it unsuitable for direct use in high-quality phosphate fertilizer production. 2. Foam conveying is prone to clogging, affecting the continuity of phosphate fertilizer production: During the foam transfer process between the roughing and cleaning cells, fine-grained mineral particles often adhere to the surface of the phosphate rock foam, which can easily clog the guide ports or connecting pipes after long-term operation. Frequent shutdowns for cleaning not only reduce equipment utilization but also disrupt phosphate fertilizer production, impacting order delivery and market supply. 3. Lagging flow rate adjustment and large fluctuations in separation conditions: Existing flotation equipment relies heavily on manual valve adjustment of slurry / foam flow rates. Limited by operator experience, it's difficult to dynamically adjust the flow rate based on phosphate ore properties. Unstable flow rates lead to fluctuations in slurry level, bubble concentration, and mineralization time within the flotation cell, affecting concentrate quality uniformity and increasing the difficulty of batching for subsequent phosphate fertilizer production. 4. Low bubble-slurry contact efficiency and reduced resource utilization: Some flotation equipment's agitation devices can only achieve overall slurry circulation, failing to specifically enhance slurry disturbance in the bubble generation zone. This results in low collision probability and poor adhesion efficiency between bubbles and mineral particles. For difficult-to-process phosphate ores, this defect further reduces the recovery rate of useful minerals (recovery loss can reach 5-8%), indirectly increasing phosphate ore consumption and production costs.

[0003] Therefore, there is an urgent need for a phosphate rock flotation device that is adapted to the needs of phosphate fertilizer production, has multi-stage gradient separation capabilities, and operates stably, in order to solve the above-mentioned technical bottlenecks and improve the quality of raw materials and economic benefits of phosphate fertilizer production. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the defects of the prior art and provide a device for multi-stage gradient separation to improve the flotation grade of phosphate rock.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: This utility model discloses a device for improving the grade of phosphate rock flotation through multi-stage gradient separation. It includes a flotation cell with a vertically fixed partition. The bottom of the partition is sealed to the bottom of the flotation cell, and its top is spaced apart from the top of the flotation cell, dividing the flotation cell into adjacent roughing and cleaning cells. A slurry inlet is located on the lower part of one side wall of the flotation cell, and a slurry outlet is located on the lower part of the opposite side wall. Both the roughing and cleaning cells have independently installed stirring components at their tops, and flow regulating components are installed on the side walls corresponding to the stirring components. A foam tank, communicating with the top of the cleaning cell, is located on the top side of the roughing cell and connected to the top of the cleaning cell via a guide port. An overflow trough is located at the top edge of the cleaning cell. A scraper assembly is also provided at the top of the cleaning cell to scrape foam into the overflow trough. A flushing component is located on the other side wall of the foam tank opposite the guide port to clean mineral deposits at the guide port outlet.

[0006] As a preferred embodiment of this utility model, the stirring assembly includes a flotation column vertically fixed at the top opening of the flotation cell, the top end of the flotation column extending to the outside of the flotation cell and fixedly connected to a top support; a rotatable rotating shaft is coaxially arranged inside the flotation column, the bottom end of the rotating shaft passing through the bottom end of the flotation column and being sealed and rotatably connected to a bearing seat in the middle of the flotation column; a guide impeller is fixedly connected to the bottom end of the rotating shaft, the guide impeller having a helical blade structure, the helical direction of which matches the rotation direction of the rotating shaft, for driving the slurry to circulate axially along the flotation column; An air inlet pipe is fixed on the middle side wall of the flotation column. The top end of the air inlet pipe extends to the outside of the flotation column and is connected to a blower, while the bottom end extends into the lower part of the flotation column to inject air bubbles into the slurry. The top end of the rotating shaft is connected to the output shaft of the stirring drive assembly fixed to the top of the flotation column via a coupling. A slurry inlet pipe is provided at the bottom of the side of the flotation column. One end of the slurry inlet pipe is connected to the inside of the flotation column, and the other end is connected to the slurry area in the flotation cell. A reagent inlet is provided at the lower part of the side of the flotation column. The reagent inlet is connected to the inside of the flotation column to inject flotation reagents.

[0007] As a preferred embodiment of this utility model, the flow regulation component includes a regulating groove vertically arranged along the side wall of the flotation cell, the regulating groove being vertically continuous and communicating with the interior of the flotation cell, and the position of the regulating groove being opposite to the outer wall of the flotation column of the stirring component; a flow regulation plate is rotatably arranged inside the regulating groove, the flow regulation plate being a rectangular flat plate, the outer wall of which is tightly fitted with the inner wall of the regulating groove, used to adjust the cross-sectional area of ​​the slurry or foam flow between the flotation cell and the stirring component; an adjusting fixing seat is fixed to the outside of the regulating groove, and two opposing rotating seats are rotatably arranged on the adjusting fixing seat, the rotating seats being connected to the regulating groove via fixed bearings. The section is rotatably connected to the fixed base; the outer wall of the flow regulating plate is fixedly connected to the inner end faces of the two rotating seats; a rotating shaft is fixedly connected to the outer wall of the rotating seat, and one end of the rotating shaft is connected to the output shaft of the angle drive motor fixed to one side of the adjusting fixed base; multiple positioning holes are evenly opened in a ring on the outer wall of the rotating seat, and an elastic pin is fixed on the outer wall of the adjusting fixed base. The elastic pin can be inserted into any one of the positioning holes to lock the rotation angle of the rotating seat; the regulating groove is also provided with a distance sensor relative to the position of the flow regulating plate. The distance sensor is used to measure the rotation angle of the flow regulating plate and feed it back to the control system.

[0008] As a preferred embodiment of this utility model, the scraper assembly includes a rotating scraper rotatably disposed on the top of both side walls of the refining tank. The rotating scraper is an elastic rubber plate, and its lower end face is in contact with the liquid surface in the refining tank. Both ends of the rotating scraper are rotatably connected to the side walls of the refining tank through bearings with seats. A scraper drive motor assembly is fixed on the top of one side wall of the refining tank. The output shaft of the scraper drive motor assembly is connected to the rotating shaft belt at one end of the rotating scraper through a reducer, for driving the rotating scraper to rotate at a uniform speed and scraping the foam into the overflow tank.

[0009] As a preferred technical solution of this utility model, the flushing assembly includes a flushing nozzle fixed on the outer wall of the foam tank. The flushing nozzle is a fan-shaped nozzle, and the spray range covers the outlet area of ​​the guide port. The flushing nozzle is connected to an external water source through a flushing water pipe. A solenoid valve is fixed on the flushing water pipe. The solenoid valve is electrically connected to the PLC control system of the flotation cell and is used to control the flushing frequency and flushing duration to remove mineral particles adhering to the outlet of the guide port.

[0010] As a preferred embodiment of this utility model, the width of the control tank is 20-50mm, and the depth matches the depth of the slurry in the flotation cell; the thickness of the flow regulating plate is 3-8mm, the material is stainless steel, and the surface is provided with a wear-resistant coating to improve service life.

[0011] As a preferred technical solution of this utility model, the number of rinsing nozzles is 1-3, arranged horizontally along the outer wall of the foam tank, and the spray pressure is 0.2-0.5MPa. The rinsing intensity can be adjusted according to the degree of mineral adhesion.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. Multi-stage gradient separation for precise matching of phosphate fertilizer raw material requirements: The flotation cell is divided into an independent roughing cell and a cleaning cell by a partition, forming a two-stage gradient separation structure of "roughing-cleaning". The roughing cell is used for preliminary enrichment of low-grade phosphate ore, removing most of the gangue minerals; the cleaning cell further purifies the froth from the roughing cell, removing residual impurities, and finally obtaining high-grade phosphate concentrate with a P2O5 content ≥32%. Compared with traditional single-stage flotation, this device increases the P2O5 content of the concentrate by 8-10% and reduces the impurity content by 3-5%, fully meeting the high standard requirements of high-end phosphate fertilizer raw materials; 2. Dynamic flow regulation ensures continuous and uniform phosphate fertilizer production: The flow regulation component, through the coordinated action of an angle-driven motor and a distance sensor, can adjust the slurry / foam flow cross-sectional area between the flotation cell and the agitation component in real time according to the properties of the phosphate ore. For example, when the raw ore grade is low, the flow cross-sectional area is increased to prolong the slurry residence time; when the raw ore has a high impurity content, the cross-sectional area is decreased to improve the foam separation accuracy. This design avoids the lag of manual adjustment, making the liquid level, bubble concentration, and mineralization time in the flotation cell stable and controllable. The deviation of concentrate P2O5 content can be reduced to within 0.5 percentage points, significantly improving the uniformity of raw material quality in phosphate fertilizer production. 3. Anti-clogging design improves the utilization rate of phosphate fertilizer equipment: The flushing components installed on the side wall of the foam tank can perform high-pressure flushing of the outlet area of ​​the guide port through a PLC control system on a timed or on-demand basis. Actual test data shows that this design can extend the clogging cycle of the guide port from the traditional 7-10 days to 30-45 days, reduce the average monthly downtime for maintenance to 2-3 hours, and increase the equipment utilization rate by more than 15%, effectively ensuring the continuity of phosphate fertilizer production; 4. Enhanced bubble-slurry contact for improved phosphorus resource utilization: The guide impeller in the agitator assembly employs a helical blade structure, matched to the rotation direction of the rotating shaft. This drives the slurry to circulate axially along the flotation column, enhancing slurry disturbance in the bubble generation zone below the air inlet pipe. This design increases the collision probability between bubbles and mineral particles by over 40%. For refractory phosphate rock, the recovery rate of useful minerals increases from the traditional 75-80% to 85-90%, while reducing phosphate rock consumption by 5-7%, significantly lowering the raw material costs for phosphate fertilizer production. Attached Figure Description

[0013] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a top view of the present invention; Figure 3 This is a cross-sectional structural diagram of the present invention; Figure 4 This is a cross-sectional structural schematic diagram (b) of this utility model; In the diagram: 1. Flotation cell; 2. Agitator assembly; 3. Flow rate regulating assembly; 4. Scraper assembly; 5. Flushing assembly; 11. Baffle plate; 12. Roughing cell; 13. Cleaning cell; 14. Slurry inlet; 15. Slurry outlet; 16. Foam tank; 17. Overflow tank; 21. Flotation column; 22. Rotating shaft; 23. Slurry inlet pipe; 24. Reagent inlet; 25. Guide impeller; 26. Air inlet pipe; 27. Agitator drive assembly; 31. Control tank. 32. Flow regulating plate; 33. Adjusting fixed seat; 34. Rotating seat; 35. Angle drive motor; 36. Rotating shaft; 37. Positioning hole; 38. Elastic pin; 39. Distance sensor; 41. Rotating scraper; 42. Scraper drive motor assembly; 43. Reducer; 44. Bearing with seat; 51. Flushing nozzle; 52. Flushing water pipe; 53. Solenoid valve; 161. Flow guide port; 221. Bearing seat; 341. Fixed bearing. Detailed Implementation

[0014] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0015] In the attached diagram, all identical reference numerals refer to the same components.

[0016] Example 1: Sorting process of conventional low-grade phosphate rock like Figure 1-4 The apparatus shown includes a flotation cell 1, which is internally divided into an adjacent roughing cell 12 and a cleaning cell 13 by a vertically fixed partition 11. A pulp inlet 14 is provided on the lower part of one side wall of the flotation cell 1, and a pulp outlet 15 is provided on the lower part of the opposite side wall, for receiving low-grade phosphate rock pulp (P2O5 content of about 20%) to be separated.

[0017] Agitation Component 2: Agitation component 2 is installed at the top of both the roughing cell 12 and the cleaning cell 13. Taking the roughing cell 12 as an example, a flotation column 21 is fixed at its top opening. The top of the flotation column 21 is connected to the top support, and a rotatable rotating shaft 22 is installed coaxially inside. The bottom end is sealed and supported in the middle of the flotation column 21 by a bearing seat 221. A guide impeller 25 with a spiral blade structure is fixed at the bottom of the rotating shaft 22, matching the rotation direction of the rotating shaft 22 (for example, when rotating clockwise, the guide impeller 25 drives the slurry to flow downward along the axial direction of the flotation column 21, and then circulates upward after being reflected from the bottom). An air inlet pipe 26 is provided on the middle side wall of the flotation column 21, and the bottom end extends into the slurry area and is connected to the blower to inject air bubbles; a slurry inlet pipe 23 is provided at the bottom of the side, which is connected to the slurry area in the flotation cell 1; a reagent inlet 24 is provided at the lower part of the side for adding flotation reagents (such as collectors and frothers). The top of the rotating shaft 22 is connected to the output shaft of the stirring drive assembly 27 (such as a motor) via a coupling, driving the guide impeller 25 to rotate.

[0018] Flow regulation component 3: A regulating tank 31 (connected vertically and internally to the flotation tank 1) is provided on the sidewalls of the coarsening tank 12 and the finer tank 13 relative to the outer wall of the flotation column 21 of the stirring component 2. A flow regulation plate 32 (rectangular flat plate, with its outer wall in contact with the inner wall of the regulating tank 31) is installed inside the regulating tank 31. It rotates via rotating seats 34 on both sides (fixed to the regulating seat 33), which are driven by an angle drive motor 35 (the rotating shaft 36 is connected to the motor output shaft). A distance sensor 39 is installed on the outside of the regulating tank 31 to measure the rotation angle (i.e., flow cross-sectional area) of the flow regulation plate 32 in real time and feeds it back to the control system for dynamic adjustment.

[0019] Foam sorting and collection: A foam trough 16 is provided on the top side of the roughing tank 12, which is connected to the top of the cleaning tank 13 through a guide port 161. During roughing, the slurry comes into full contact with the bubbles under the action of the stirring component 2. Useful minerals adhere to the bubbles and float to the surface to form roughing foam, which flows into the cleaning tank 13 through the foam trough 16. An overflow trough 17 is provided at the top edge of the cleaning tank 13 to collect the high-grade concentrate foam from secondary enrichment; rotating scrapers 41 (elastic rubber plates with their lower end in contact with the liquid surface) are provided on the top of both side walls. The scraper is driven by a motor assembly 42 through a reducer 43 to rotate, scraping the foam into the overflow trough 17 at a uniform speed.

[0020] Anti-clogging design: The outer wall of the foam tank 16 is equipped with a flushing assembly 5, including a fan-shaped flushing nozzle 51 (the spray range covers the outlet of the guide port 161), which is connected to an external water source through a flushing water pipe 52. A solenoid valve 53 (controlled by a PLC) is installed on the water pipe. When mineral particles are detected adhering to the guide port 161, the solenoid valve 53 opens, and a high-pressure water flow (0.2-0.5MPa) flushes away the adhering particles, ensuring smooth foam delivery.

[0021] In this embodiment, the roughing tank 12 completes the initial enrichment of low-grade phosphate rock (removing 70-80% of gangue minerals), the fine tank 13 further purifies it (removing the remaining 20-30% of impurities), and finally the concentrate collected by the overflow tank 17 has a P2O5 content of more than 32%, which meets the production requirements of food-grade diammonium phosphate.

[0022] Example 2: Sorting process of refractory phosphate rock (fine particle size, high impurity content) The structure of this device is the same as that of Example 1, with a focus on enhancing the slurry circulation of the stirring component 2 and the anti-clogging function of the flushing component 5 to meet the sorting challenges of collophane (where useful minerals and gangue minerals are closely interspersed and the particles are fine).

[0023] The stirring assembly 2 is optimized as follows: the angle of the spiral blades of the guide impeller 25 is increased (steeper than in Example 1), and the rotational speed of the rotating shaft 22 is increased (from 50 rpm to 70 rpm), enhancing the circulation velocity of the slurry along the axial direction of the flotation column 21 (the slurry velocity is increased from 0.1 m / s to 0.15 m / s). Branch nozzles (2-3 in number) are added to the air inlet pipe 26, evenly distributed at the bottom of the flotation column 21, injecting finer bubbles (the bubble diameter is reduced from 2-3 mm to 1-2 mm), increasing the probability of collision between bubbles and fine-grained phosphate minerals.

[0024] The flushing assembly 5 was enhanced: the number of flushing nozzles 51 was increased to 3 (arranged horizontally along the outer wall of the foam tank 16), the spray pressure was increased to 0.5 MPa (an increase of 0.1 MPa compared to Example 1), and the flushing frequency was shortened from once every 2 hours to once every 1 hour (automatically controlled by the PLC based on the mineral adhesion sensor signal at the guide port 161). Actual test data showed that during phosphate rock sorting, the clogging cycle of the guide port 161 was extended from 7 days in conventional equipment to 40 days, ensuring continuous sorting.

[0025] In this embodiment, the roughing tank 12 enhances mineralization through strong circulation and dense bubbles, allowing fine-grained useful minerals (accounting for about 40%) in the collophane to fully adhere to the bubbles; the cleaning tank 13, through secondary enrichment, increases the P2O5 content of the concentrate from 20% (collophane ore) to more than 35%, and reduces the impurity (such as MgO) content to below 1.5% (conventional equipment can only reduce it to 2.5%), meeting the production requirements of high-end monoammonium phosphate.

[0026] Example 3: Adaptive multi-mineral sorting with dynamic flow regulation This device is designed for scenarios where the grade of phosphate rock ore fluctuates greatly (such as P2O5 content fluctuating between 15-25%), and focuses on demonstrating the dynamic control function of the flow regulation component 3.

[0027] The working process of the flow regulating component 3 is as follows: When the P2O5 content of the slurry entering through the slurry inlet 14 is less than 20% (low grade), the distance sensor 39 detects the initial angle of the flow regulating plate 32 (corresponding to a smaller flow cross-sectional area), and the control system commands the angle drive motor 35 to rotate the rotating seat 34 counterclockwise, increasing the rotation angle of the flow regulating plate 32 (increasing the flow cross-sectional area by 20%), and extending the residence time of the slurry in the mixing component 2 (from 8 minutes to 10 minutes), ensuring that low-grade minerals are fully separated; when the P2O5 content of the slurry is higher than 22% (high grade), the flow regulating plate 32 rotates in the opposite direction (reducing the flow cross-sectional area by 15%), shortening the residence time (from 8 minutes to 6.5 minutes), avoiding waste of reagents and increase of concentrate impurities caused by over-separation.

[0028] In this embodiment, the dynamic response time of the flow regulation component 3 is ≤5 seconds, which enables the concentrate P2O5 content to be ≥32% (fluctuation ≤0.5 percentage points) during the sorting process of phosphate rock of different grades (15-25% P2O5), significantly improving the uniformity of raw material quality in phosphate fertilizer production.

[0029] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A device for improving the grade of phosphate rock flotation through multi-stage gradient separation, comprising a flotation cell (1), wherein a partition (11) is vertically fixed inside the flotation cell (1), the bottom end of the partition (11) is sealed to the bottom of the flotation cell (1), and the top end is spaced apart from the top of the flotation cell (1), dividing the flotation cell (1) into adjacent roughing cells (12) and cleaning cells (13); a slurry inlet (14) is provided at the lower part of one side wall of the flotation cell (1), and a slurry outlet (15) is provided at the lower part of the opposite side wall; both the roughing cell (12) and the cleaning cell (13) are independently provided with stirring components (2) at the top, and the side walls are connected to the stirring components (2). Each of the corresponding positions is provided with a flow regulating component (3); the top side of the coarse selection tank (12) is provided with a foam tank (16) that communicates with the top of the fine selection tank (13), and the foam tank (16) is connected to the top of the fine selection tank (13) through a guide port (161); the top edge of the fine selection tank (13) is provided with an overflow tank (17); the top of the fine selection tank (13) is also provided with a scraper component (4) for scraping foam into the overflow tank (17); the foam tank (16) is provided with a flushing component (5) on the other side wall opposite to the guide port (161) for cleaning the mineral adhering at the outlet of the guide port (161).

2. The apparatus for improving the grade of phosphate rock flotation through multi-stage gradient separation according to claim 1, characterized in that, The stirring assembly (2) includes a flotation column (21) vertically fixed at the top opening of the flotation cell (1). The top end of the flotation column (21) extends to the outside of the flotation cell (1) and is fixedly connected to the top support. A rotatable rotating shaft (22) is coaxially arranged inside the flotation column (21). The bottom end of the rotating shaft (22) passes through the bottom end of the flotation column (21) and is sealed and rotatably connected to the bearing seat (221) in the middle of the flotation column (21). A guide impeller (25) is fixedly connected to the bottom end of the rotating shaft (22). The guide impeller (25) has a spiral blade structure, and its spiral direction matches the rotation direction of the rotating shaft (22), which is used to drive the slurry to circulate along the axial direction of the flotation column (21). The middle of the flotation column (21) An air inlet pipe (26) is fixed on the side wall. The top end of the air inlet pipe (26) extends to the outside of the flotation column (21) and is connected to the blower. The bottom end extends into the lower part of the flotation column (21) for injecting air bubbles into the slurry. The top end of the rotating shaft (22) is connected to the output shaft of the stirring drive assembly (27) fixed to the top of the flotation column (21) through a coupling. A slurry inlet pipe (23) is provided at the bottom of the side of the flotation column (21). One end of the slurry inlet pipe (23) is connected to the inside of the flotation column (21), and the other end is connected to the slurry area in the flotation cell (1). A reagent inlet (24) is provided at the lower part of the side of the flotation column (21). The reagent inlet (24) is connected to the inside of the flotation column (21) for injecting flotation reagents.

3. The apparatus for improving the grade of phosphate rock flotation through multi-stage gradient separation according to claim 1, characterized in that, The flow regulating component (3) includes a regulating groove (31) vertically arranged along the side wall of the flotation cell (1). The regulating groove (31) is vertically connected and communicates with the interior of the flotation cell (1). The position of the regulating groove (31) is opposite to the outer wall of the flotation column (21) of the stirring component (2). A flow regulating plate (32) is rotatably arranged inside the regulating groove (31). The flow regulating plate (32) is a rectangular plate, and its outer wall is tightly fitted with the inner wall of the regulating groove (31). It is used to adjust the cross-sectional area of ​​the slurry or foam flow between the flotation cell (1) and the stirring component (2). An adjusting fixing seat (33) is fixed on the outside of the regulating groove (31). Two opposing rotating seats (34) are rotatably arranged on the adjusting fixing seat (33). The rotating seats (34) are rotatably connected to the adjusting fixing seat (33) through a fixed bearing (341). The outer wall of the flow regulating plate (32) is fixedly connected to the inner end faces of the two rotating seats (34); a rotating shaft (36) is fixedly connected to the outer wall of the rotating seat (34), and one end of the rotating shaft (36) is connected to the output shaft of the angle drive motor (35) fixed on one side of the adjusting fixed seat (33); a plurality of positioning holes (37) are evenly opened along the annular shape on the outer wall of the rotating seat (34), and an elastic pin (38) is fixed on the outer wall of the adjusting fixed seat (33). The elastic pin (38) can be inserted into any one of the positioning holes (37) to lock the rotation angle of the rotating seat (34); a distance sensor (39) is also provided in the regulating groove (31) relative to the position of the flow regulating plate (32). The distance sensor (39) is used to measure the rotation angle of the flow regulating plate (32) and feed it back to the control system.

4. The apparatus for improving the grade of phosphate rock flotation through multi-stage gradient separation according to claim 1, characterized in that, The scraper assembly (4) includes a rotating scraper (41) rotatably mounted on the top of the two side walls of the selection tank (13). The rotating scraper (41) is an elastic rubber plate, and its lower end face is in contact with the liquid surface in the selection tank (13). The two ends of the rotating scraper (41) are rotatably connected to the side wall of the selection tank (13) through bearings (44). A scraper drive motor assembly (42) is fixed on the top of one side wall of the selection tank (13). The output shaft of the scraper drive motor assembly (42) is connected to the rotating shaft belt at one end of the rotating scraper (41) through a reducer (43) to drive the rotating scraper (41) to rotate at a uniform speed and scrape the foam into the overflow tank (17).

5. The apparatus for improving the grade of phosphate rock flotation through multi-stage gradient separation according to claim 1, characterized in that, The flushing assembly (5) includes a flushing nozzle (51) fixed on the outer wall of the foam tank (16). The flushing nozzle (51) is a fan-shaped nozzle, and the spray range covers the outlet area of ​​the guide port (161). The flushing nozzle (51) is connected to an external water source through a flushing water pipe (52). A solenoid valve (53) is fixed on the flushing water pipe (52). The solenoid valve (53) is electrically connected to the PLC control system of the flotation cell (1) to control the flushing frequency and flushing duration, and to remove mineral particles adhering to the outlet of the guide port (161).

6. The apparatus for improving the grade of phosphate rock flotation through multi-stage gradient separation according to claim 3, characterized in that, The width of the control tank (31) is 20-50mm, and the depth matches the depth of the slurry in the flotation tank (1); the thickness of the flow regulating plate (32) is 3-8mm, the material is stainless steel, and the surface is provided with a wear-resistant coating to improve service life.

7. The apparatus for improving the grade of phosphate rock flotation through multi-stage gradient separation according to claim 5, characterized in that: The number of the flushing nozzles (51) is 1-3, arranged horizontally along the outer wall of the foam tank (16), and their spray pressure is 0.2-0.5MPa. The flushing intensity can be adjusted according to the degree of mineral adhesion.

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