A tailings concentration system

Abstract

The application provides a tailing concentration system, which comprises a horizontal screw centrifuge and a plate-and-frame filter press in sequence along a tailing conveying direction, the horizontal screw centrifuge is arranged to concentrate tailings with an initial concentration to form tailings with a target concentration and fluidity, a medicament adding part is arranged on the horizontal screw centrifuge, and the medicament adding part is arranged to add a medicament capable of clarifying separated liquid during dehydration of the tailings by the horizontal screw centrifuge. The tailing concentration system uses the horizontal screw centrifuge for tailing concentration, and uses the horizontal screw centrifuge as a front process of the plate-and-frame filter press. Compared with a single plate-and-frame filter press, the tailing concentration system shortens the processing time and improves the dehydration efficiency. Compared with a single dehydration horizontal screw centrifuge, the tailing concentration system has low energy consumption and large processing capacity.

Description

Technical Field

[0001] This invention relates to the field of tailings concentration technology, and more particularly to a tailings concentration system. Background Technology

[0002] Tailings are generated during ore washing and beneficiation operations, with low content of useful components and relatively low economic value. In my country, tailings are classified as industrial solid waste. Tailings have a high moisture content and are in a fluid state. Previously, a simple method of direct discharge into tailings dams was used for disposal. While this method was inexpensive, it carried significant safety risks, and the tailings dams had limited capacity. Therefore, it is necessary to compress the tailings volume by first dewatering them to reduce their moisture content before piling them into tailings dams.

[0003] Traditional tailings dewatering uses plate and frame filter presses. This equipment operates intermittently and is inefficient. For processing volumes of thousands of cubic meters per hour, a large number of filter presses are required, resulting in a large footprint, high labor intensity, and the need for high concentrations in the filter presses to reduce pressing time. Large horizontal screw centrifuges can also be used for tailings dewatering, but the equipment has high energy consumption and the dewatering dryness is lower than that of plate and frame filter presses. Therefore, both types of equipment have drawbacks.

[0004] Therefore, in order to solve the problems of low processing efficiency of plate and frame filter presses and high energy consumption of horizontal screw centrifuges in the existing technologies, this invention proposes a tailings concentration system. Summary of the Invention

[0005] To address the problems existing in the application of current tailings dewatering equipment, this invention provides a tailings concentration system.

[0006] According to one objective of the present invention, a tailings concentration system is provided, comprising, in sequence along the tailings conveying direction, a horizontal screw centrifuge and a plate and frame filter press, wherein the horizontal screw centrifuge is configured to concentrate tailings of initial concentration into tailings of target concentration and with fluidity, and the horizontal screw centrifuge is provided with a reagent dosing section, wherein the reagent dosing section is configured to add a reagent capable of clarifying the separated liquid during the tailings dewatering process in the horizontal screw centrifuge;

[0007] A controller is configured to adjust the dosage of the reagent in the reagent dosing unit and the rotation speed of the horizontal screw centrifuge in real time based on the concentration value of the tailings output by the horizontal screw centrifuge, so as to maintain the tailings output by the horizontal screw centrifuge at the target concentration.

[0008] Preferably, the initial concentration of the tailings is 10-15%, and the target concentration is 45-55% of the initial concentration.

[0009] Preferably, the horizontal decanter centrifuge includes a separation straight section and a separation conical section arranged sequentially along its length. The separation straight section and the separation conical section are integrally connected, and the inner and outer sides of the separation straight section and the separation conical section are continuously arranged.

[0010] Preferably, the included angle between the separating conical segment and the separating straight segment is in the range of 15 to 20°.

[0011] Preferably, the horizontal decanter centrifuge is model LW350, the angle between the separating cone section and the separating straight section is 15°, and the effective volume of the rotor in the horizontal decanter centrifuge is 83.4L.

[0012] Preferably, the horizontal decanter centrifuge is made of 2304 duplex stainless steel with a yield strength of 400MPa and a drum wall thickness of 10mm. The rotor drive mode of the horizontal decanter centrifuge is a single motor mode, and the operating energy consumption of the horizontal decanter centrifuge is 2kWh.

[0013] Preferably, there is a gap between the inner wall of the drum and the spiral pusher blades of the horizontal screw centrifuge, and the gap is no greater than 0.3 mm.

[0014] Preferably, the controller adjusts the reagent dosage in the reagent dosing section and the rotation speed of the horizontal screw centrifuge in real time based on the concentration value of the tailings output by the horizontal screw centrifuge, so as to maintain the tailings output by the horizontal screw centrifuge at the target concentration, specifically including the following steps:

[0015] S1. Determine whether the concentration of the tailings output from the horizontal screw centrifuge is higher than the target concentration;

[0016] If the concentration of the tailings output by the decanter centrifuge is higher than the target concentration, the controller reduces the speed of the decanter centrifuge; conversely, if the concentration of the tailings output by the decanter centrifuge is lower than the target concentration, the controller increases the speed of the decanter centrifuge.

[0017] S2. After a preset time, determine again whether the concentration of the tailings output by the horizontal screw centrifuge is higher than the target concentration;

[0018] If the concentration of the tailings output by the horizontal screw centrifuge is higher than the target concentration, the controller controls the reagent dosing unit to reduce the dosage; conversely, if the concentration of the tailings output by the horizontal screw centrifuge is lower than the target concentration, the reagent dosing unit increases the dosage.

[0019] S3. Determine again whether the concentration of the tailings output from the horizontal screw centrifuge is higher than the target concentration;

[0020] If the judgment result is the same as the judgment result in steps S1 and S2, an alarm will be triggered indicating that manual intervention is required.

[0021] Preferably, the dosage range of the agent addition section is 0.8 to 1.1 kg of dry powder agent per ton of absolutely dry mud, and the separation factor range of the horizontal screw centrifuge is 900 to 1300 g.

[0022] Preferably, the tailings concentration system further includes an alarm, and the controller is configured to start and stop the alarm based on the concentration value of the tailings output by the horizontal screw centrifuge;

[0023] The horizontal screw centrifuge has a collection tank at its sludge outlet, and a concentration meter is installed on the tank body. The concentration meter is electrically connected to the controller.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This tailings thickening system uses a horizontal screw centrifuge for tailings thickening as a pre-process of plate and frame filter press. The horizontal screw centrifuge is used to initially thicken the tailings, which are then sent to the plate and frame filter press for dewatering. Compared with a single plate and frame filter press, the processing time is shortened and the dewatering efficiency is improved. Compared with a horizontal screw centrifuge used for dewatering alone, the horizontal screw centrifuge used for thickening has lower energy consumption and larger processing capacity.

[0026] Furthermore, the controller adjusts the dosage of the reagent in the reagent addition section and the rotation speed of the decanter centrifuge in real time based on the concentration value of the tailings output by the decanter centrifuge, so as to maintain the tailings output by the decanter centrifuge at the target concentration, so that the tailings fed into the plate and frame filter press have a certain fluidity, and realize the continuous processing of tailings.

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a schematic cross-sectional view of a horizontal screw centrifuge in a tailings concentration system according to the present invention;

[0029] Figure 2 This is a schematic diagram showing the connection between the separation cone section and the separation straight section of a horizontal screw centrifuge in a tailings concentration system according to the present invention;

[0030] Figure 3 This is a schematic diagram showing the connection between the separating cone section and the separating straight section of a conventional horizontal screw centrifuge.

[0031] Figure 4 This is a schematic diagram of the control logic of a tailings concentration system controller according to the present invention. Detailed Implementation

[0032] The following description is intended to provide a detailed account of the invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0033] This invention provides a technical solution: a tailings concentration system, which, along the tailings conveying direction, sequentially includes: a horizontal screw centrifuge and a plate and frame filter press, wherein the horizontal screw centrifuge is used for tailings concentration as a pre-process of the plate and frame filter press;

[0034] The horizontal screw centrifuge is configured to concentrate tailings of initial concentration to a target concentration, wherein the tailings of the target concentration are fluid.

[0035] Preferably, the concentration of the tailings after concentration by the horizontal screw centrifuge, i.e., the target concentration, is controlled at 45-55% of the initial concentration to give it a certain degree of fluidity. The concentrated tailings need to be pumped into a plate and frame filter press, so the concentration of the concentrated tailings needs to be controlled. It cannot be too high, which would prevent the pump from delivering the material, and it cannot be too low, which would affect the efficiency. In this embodiment, the initial concentration of the tailings is 10-15%, and the target concentration of the tailings is 50% of the initial concentration.

[0036] When in use, this tailings thickening system uses a horizontal screw centrifuge to thicken the tailings as a pre-process of plate and frame filter press. The horizontal screw centrifuge concentrates the tailings with a concentration of about 10-15% to about 50%. At this point, the tailings still have a certain degree of fluidity. Then, it is sent to the plate and frame filter press for dewatering. This shortens the plate and frame pressing time, increases the hourly processing capacity, and improves the dewatering efficiency by more than 100%. Compared with the horizontal screw centrifuge used for dewatering, the thickening centrifuge has lower energy consumption and a larger processing capacity.

[0037] See Figure 1 ,exist Figure 1 In the diagram, D is the diameter of the drum, L is the effective length of the drum, L1 is the length of the straight section (i.e., the separation straight section 100), a is the angle between the separation cone section 200 and the separation straight section 100, d is the diameter of the spiral shaft, and H is the depth of the liquid pool.

[0038] The horizontal decanter centrifuge includes a separating straight section 100 and a separating conical section 200 arranged sequentially along its length. The inner and outer sides of the separating straight section 100 and the separating conical section 200 are continuously arranged. The included angle α between the separating conical section 200 and the separating straight section 100 is greater than 8°. Preferably, the included angle α between the separating conical section 200 and the separating straight section 100 is in the range of 15° to 20°.

[0039] In this embodiment, the horizontal screw centrifuge is model LW350. Compared with the traditional LW350 centrifuge, the included angle α between the separation cone section 200 and the separation straight section 100 is changed from the common 8° to 15°, the diameter of the screw shaft is reduced by 10mm, and the effective volume of the rotor in the horizontal screw centrifuge is increased from 71L to 83.4L, an increase of about 17%. Under the same feed rate, the centrifuge separation factor is reduced from 1300g to about 1000g.

[0040] By increasing the angle α between the straight separation section 100 and the conical separation section 200, the length of the straight separation section 100 is increased, thus increasing the separation section length. Simultaneously, the diameter d of the helical shaft is reduced, thereby increasing the liquid pool depth H. The combination of these two factors increases the effective volume of the rotor.

[0041] Further, see Figure 1 and 2 The straight separating section 100 and the conical separating section 200 are integrally connected, which is consistent with the prior art. (See also...) Figure 3 The flange bolt fixing method of the separation straight section 100 and separation conical section 200 has been changed to a straight-conical integrated type to reduce the impact of wind resistance and reduce weight.

[0042] Furthermore, the decanter centrifuge, while reducing the rotational speed, utilizes high-strength materials. In this embodiment, the decanter centrifuge is model LW350. The original LW350 centrifuge used 321 stainless steel with a yield strength of 205 MPa, while this embodiment uses 2304 duplex stainless steel with a yield strength of 400 MPa. The drum wall thickness is reduced from 12 mm to 10 mm, nearly doubling the material strength. This reduction in wall thickness does not affect the rotor's strength or rigidity. With the reduced wall thickness, the rotor's mass decreases by nearly 10%, and the moment of inertia decreases proportionally. The rotor drive mode is changed from a dual-motor mode to a single-motor mode, and the screw drive shaft is fixed to maintain a high differential speed. Considering all factors, the unit operating energy consumption is ultimately reduced to 2 kWh. While meeting strength requirements, the screw blade pitch is increased by 20%, allowing for faster solid transport and clearer liquid transport.

[0043] Furthermore, there is a gap between the inner wall of the drum and the spiral pusher blades of the horizontal screw centrifuge. This gap is unavoidable due to the relative motion between the drum and the spiral. Material will remain in the gap. The smaller the gap, the better the concentration effect and solid conveying. Preferably, the gap is no greater than 0.3 mm. In this embodiment, the gap is controlled at 0.3 mm.

[0044] In this embodiment, the horizontal screw centrifuge is provided with a reagent dosing section, which is configured to add a reagent that can clarify the separated liquid during the dewatering process of tailings in the horizontal screw centrifuge;

[0045] The tailings concentration system also includes:

[0046] A controller is configured to adjust the dosage of the reagent in the reagent dosing section and the rotation speed of the horizontal screw centrifuge in real time based on the concentration value of the tailings output by the horizontal screw centrifuge, so as to maintain the tailings output by the horizontal screw centrifuge at the target concentration.

[0047] An alarm, wherein the controller is configured to activate or deactivate the alarm based on the concentration value of the tailings output from the horizontal screw centrifuge.

[0048] The horizontal screw centrifuge has a collection tank at its sludge outlet. A concentration meter is installed on the tank body to monitor the concentration in real time. The concentration meter is electrically connected to the controller.

[0049] Specifically, if the concentration of the tailings output by the decanter centrifuge is higher than the target concentration, the controller reduces the speed of the decanter centrifuge. After a period of time, if the concentration of the tailings output by the decanter centrifuge does not decrease, the controller controls the reagent dosing unit to reduce the dosage and then checks again whether the concentration of the tailings output by the decanter centrifuge is higher than the target concentration. If the concentration of the tailings output by the decanter centrifuge is still higher than the target concentration, the controller activates the alarm, prompting manual intervention. Conversely, if the concentration of the tailings output by the decanter centrifuge is lower than the target concentration, the controller increases the speed of the decanter centrifuge and the dosage of the reagent dosing unit.

[0050] More specifically, the control logic of the controller is described in [reference needed]. Figure 4 The controller adjusts the dosage of the reagent in the reagent dosing section and the rotation speed of the decanter centrifuge in real time based on the concentration of the tailings output by the decanter centrifuge, so as to maintain the tailings output by the decanter centrifuge at the target concentration. Specifically, this includes the following steps:

[0051] S1. Determine whether the concentration of the tailings output from the horizontal screw centrifuge is higher than the target concentration;

[0052] If the concentration of the tailings output by the decanter centrifuge is higher than the target concentration, the controller reduces the speed of the decanter centrifuge; conversely, if the concentration of the tailings output by the decanter centrifuge is lower than the target concentration, the controller increases the speed of the decanter centrifuge.

[0053] S2. After a preset time, determine again whether the concentration of the tailings output by the horizontal screw centrifuge is higher than the target concentration;

[0054] If the concentration of the tailings output by the horizontal screw centrifuge is higher than the target concentration, the controller controls the reagent dosing unit to reduce the dosage; conversely, if the concentration of the tailings output by the horizontal screw centrifuge is lower than the target concentration, the reagent dosing unit increases the dosage.

[0055] S3. Determine again whether the concentration of the tailings output from the horizontal screw centrifuge is higher than the target concentration;

[0056] If the judgment result is the same as the judgment result in steps S1 and S2, an alarm will be triggered indicating that manual intervention is required.

[0057] In this embodiment, the dosage of the agent added in the agent addition section is 0.8 to 1.1 kg of dry powder agent per ton of absolutely dry mud, and the separation factor of the horizontal screw centrifuge is 900 to 1300 g.

[0058] Traditional centrifuges require the addition of a certain amount of reagent to clarify the separated liquid during tailings dewatering. Simultaneously, high-speed rotation forces the dry tailings through a BD plate inside the centrifuge and out. The BD plate's function is to intercept the liquid while providing a pressure difference, facilitating the smoother discharge of solids. The magnitude of the pressure difference is determined by the centrifuge's rotational speed; higher speeds result in higher pressure differences, which is more conducive to solid discharge. High rotational speeds (separation factor above 1500g) are typically maintained to ensure effective dewatering. Due to the high-speed rotation of the centrifuge, it consumes a large amount of electrical energy. It is estimated that the operating energy consumption for processing one ton of 10% concentration wet tailings is approximately 2.2 kWh. In this embodiment, the horizontal screw centrifuge used for tailings concentration, based on a new structural design, eliminates the BD plate, reduces the operating speed, and decreases the unit operating energy consumption.

[0059] The embodiments described above are only used to illustrate the technical ideas and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The scope of patent application of the present invention should not be limited by these embodiments. That is, any equivalent changes or modifications made in accordance with the spirit disclosed in the present invention still fall within the patent scope of the present invention.

Claims

1. A tailings concentration system, characterized in that, Along the tailings conveying direction, the tailings concentration system sequentially includes: a horizontal screw centrifuge and a plate and frame filter press. The horizontal screw centrifuge is configured to concentrate tailings of initial concentration into tailings of target concentration and with fluidity. The horizontal screw centrifuge is equipped with a reagent addition section, which is configured to add a reagent that can clarify the separated liquid during the tailings dewatering process in the horizontal screw centrifuge. A controller is configured to adjust the dosage of the reagent in the reagent dosing section and the rotation speed of the horizontal screw centrifuge in real time based on the concentration value of the tailings output by the horizontal screw centrifuge, so as to maintain the tailings output by the horizontal screw centrifuge at the target concentration. The controller adjusts the reagent dosage in the reagent dosing section and the rotation speed of the horizontal screw centrifuge in real time based on the concentration value of the tailings output by the horizontal screw centrifuge, so as to maintain the tailings output by the horizontal screw centrifuge at the target concentration. Specifically, it includes the following steps: S1. Determine whether the concentration of the tailings output from the horizontal screw centrifuge is higher than the target concentration; If the concentration of the tailings output by the decanter centrifuge is higher than the target concentration, the controller reduces the speed of the decanter centrifuge; conversely, if the concentration of the tailings output by the decanter centrifuge is lower than the target concentration, the controller increases the speed of the decanter centrifuge. S2. After a preset time, determine again whether the concentration of the tailings output by the horizontal screw centrifuge is higher than the target concentration; If the concentration of the tailings output by the horizontal screw centrifuge is higher than the target concentration, the controller controls the reagent dosing unit to reduce the dosage; conversely, if the concentration of the tailings output by the horizontal screw centrifuge is lower than the target concentration, the reagent dosing unit increases the dosage. S3. Determine again whether the concentration of the tailings output from the horizontal screw centrifuge is higher than the target concentration; If the judgment result is the same as the judgment result in steps S1 and S2, an alarm will be triggered indicating that manual intervention is required.

2. A tailings concentration system according to claim 1, characterized in that, The initial concentration of the tailings is 10-15%, and the target concentration is 45-55% of the initial concentration.

3. A tailings concentration system according to claim 1, characterized in that, The horizontal screw centrifuge includes a separation straight section and a separation conical section arranged sequentially along its length. The separation straight section and the separation conical section are integrally connected, and the inner and outer sides of the separation straight section and the separation conical section are continuously arranged.

4. A tailings concentration system according to claim 3, characterized in that, The included angle between the separating conical segment and the separating straight segment is in the range of 15 to 20°.

5. A tailings concentration system according to claim 4, characterized in that, The horizontal decanter centrifuge is model LW350, the angle between the separating cone section and the separating straight section is 15°, and the effective volume of the rotor in the horizontal decanter centrifuge is 83.4L.

6. A tailings concentration system according to claim 5, characterized in that, The horizontal decanter centrifuge is made of 2304 duplex stainless steel with a yield strength of 400MPa and a drum wall thickness of 10mm. The rotor of the horizontal decanter centrifuge is driven by a single motor and the operating energy consumption of the horizontal decanter centrifuge is 2kWh.

7. A tailings concentration system according to claim 1, characterized in that, There is a gap between the inner wall of the rotating drum and the spiral pusher blades of the horizontal screw centrifuge, and the gap is no greater than 0.3 mm.

8. A tailings concentration system according to claim 1, characterized in that, The dosage range of the reagent addition section is 0.8 to 1.1 kg of dry powder reagent per ton of absolutely dry mud, and the separation factor range of the horizontal screw centrifuge is 900 to 1300 g.

9. A tailings concentration system according to claim 1, characterized in that, The tailings concentration system also includes an alarm, and the controller is configured to start and stop the alarm based on the concentration value of the tailings output by the horizontal screw centrifuge. The horizontal screw centrifuge has a collection tank at its sludge outlet, and a concentration meter is installed on the tank body. The concentration meter is electrically connected to the controller.

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