Jet flow and vortex coupling pre-mineralization flotation device and method

Abstract

The invention provides a jet flow and vortex coupling pre-mineralization flotation device and method, and relates to the technical field of flotation. The device comprises a stirring barrel, a circulating pump, a pre-mineralization pipe and a column floating tank body, ore pulp in the stirring barrel is conveyed to the pre-mineralization pipe through the circulating pump, high-pressure jet flow is formed in the pre-mineralization pipe, meanwhile, pre-mineralization of the ore pulp is completed based on the vortex effect generated by a vortex generator in the pre-mineralization pipe, and the bottom of the pre-mineralization pipe is connected with the column floating tank body; and flotation of ore pulp is completed in the column flotation tank body. The device is simple in structure, can effectively improve the recovery rate of-10 [mu] m fine-fraction minerals, and has remarkable industrial value for improving the recovery rate of superfine target minerals in a dressing plant.

Description

Technical Field

[0001] This invention relates to the field of flotation technology, and in particular to a jet vortex coupled pre-mineralization flotation device and method. Background Technology

[0002] In recent years, the increasing characteristics of mineral resources—namely, their scarcity, fineness, and complexity—have brought new challenges to the resource utilization of minerals, and at the same time, have placed higher demands on flotation equipment. In conventional flotation machines, both the mineralization and separation zones are located inside the tank. The stirring intensity directly affects the separation performance; weak turbulence results in poor mineralization in the mineralization zone, while high turbulence easily induces the desorption of mineral particles from the surface of mineralization bubbles. Traditional flotation columns, due to the needs of mineralization and separation, have relatively large column height and diameter, making it easy for mineral particles attached to the surface to detach during the rising of mineralization bubbles.

[0003] Currently, there are many methods to enhance the flotation of fine-grained minerals, mainly including micro / nano bubble flotation, coarse-grained carrier flotation, flotation column technology, interface control and reagent optimization, and hydrodynamic enhancement. In practical industrial applications, micro / nano bubble flotation, coarse-grained carrier flotation, and flotation column technology are the most common. With the current level of technology, although these three mainstream technologies can effectively improve the recovery rate of fine particles (e.g., carrier flotation in the Fankou lead-zinc mine increases the recovery rate of fine slime by 15%–20%), they still have significant limitations: for example, micro / nano bubble technology relies on energy-intensive equipment (such as pressurized dissolved air tanks), and ore pulp ions can easily interfere with bubble stability; coarse-grained carrier flotation is limited by the natural particle size distribution of the ore, requires artificial addition of carriers for "lean, fine, and impurity" ores, and carries the risk of non-selective entrainment. Summary of the Invention

[0004] To address the technical problem of low separation efficiency for ultrafine minerals in existing technologies, this invention provides a jet-vortex coupled pre-mineralization flotation device and method. The technical solution is as follows:

[0005] A jet eddy current coupled pre-mineralization flotation device includes: a stirring tank, a circulating pump, a nozzle base, a pre-mineralization pipe, a column flotation tank, and a support. The mixing tank is placed flat on the support base, and the circulation pump is placed on the support partition above the mixing tank. The bottom of the premineralized pipe extends into the column float tank, and the bottom outlet of the premineralized pipe is located in the lower middle position of the column float tank. The premineralized pipe and the column float tank are fixed to the support vertical rod by clamps. The inlet pipe of the circulating pump extends into the mixing tank, and the outlet pipe of the circulating pump is connected to the slurry inlet of the nozzle base. The nozzle base is sealed at the bottom with a pre-mineralization tube; The nozzle base is provided with an air inlet on the side, which is connected to an air inlet pipe (based on the Venturi effect, the jet generates negative pressure, and the gas is drawn into the pre-mining pipe device by itself; here, the air intake only needs to be controlled by a gas flow meter). The pre-mineralized tube contains uniformly distributed eddy current generators.

[0006] The ring pump is a variable frequency multistage centrifugal pump with a flow range of 2-20 m³ / h. 3 / h, with a head of 20-60 m, the slurry jet pressure can be changed by altering the frequency of the circulating pump to adapt to different slurry properties; A pressure gauge is installed on the outlet pipe of the circulating pump.

[0007] The nozzle base includes a slurry inlet, a nozzle, an air inlet, and a flange. The flange is located at the bottom of the nozzle base, and the nozzle base is fixed to the top of the pre-mineralized pipe by the flange. The top of the nozzle base is a slurry inlet, which is connected to the nozzle inside the nozzle base; The air inlet is located in the middle of the side of the cylindrical nozzle base, and the bottom outlet of the nozzle is flush with the axis of the air inlet. The nozzle base cylinder has 2-8 air inlets evenly distributed on its side, and the air inlet pipe connected to the air inlet is equipped with a gas flow meter.

[0008] The inner wall of the premineralized pipe is embedded with vortex generators. 2-8 vortex generators are evenly distributed in each layer around the inner wall of the premineralized pipe. The vortex generators in adjacent layers are staggered in the premineralized pipe with a distance of 5-20cm between layers. Spiral guide vanes are installed at the bottom of the premineralized pipe.

[0009] The ratio of the inner diameter to the height of the nozzle base is 1:1.5, the inner diameter of the nozzle outlet is in the range of 3-12mm, the ratio of the inner diameter of the nozzle to the inner diameter of the nozzle base is in the range of 1:10 to 1:12, and the ratio of the inner diameter of the air inlet to the inner diameter of the nozzle base is 1:15.

[0010] The eddy current generator is a conical eddy current generator or a wedge-shaped eddy current generator, and the ratio of the length, width and height of the eddy current generator to the inner diameter of the premineralized pipe is 3:3:4:12. The diameter of the spiral guide vane is the same as the inner diameter of the premineralized pipe, the blade rotation is 90°-180°, and the height is 50-200mm.

[0011] The column-floating trough includes an overflow weir, a trough body, a flow stabilizer, and a ore separator. The trough is a structure with a cylindrical upper part and a conical lower part. The ratio of the inner diameter of the trough to the height of the cylindrical part is 1:3, and the ratio of the height of the cone to the height of the cylinder is 1:5. The bottom of the cone has a bottom flow discharge port, and the side of the cone has a middlings discharge port located two-thirds of the way from the bottom. The middlings discharge port is connected to the bottom outlet of the separator via a flexible hose.

[0012] The top of the tank is an overflow weir, and the bottom of the overflow weir has an outlet for foam products. A flow stabilizing plate is installed 10-20cm above the bottom outlet of the pre-mineralized pipe in the tank. The flow stabilizing plate has a central circular hole in the center. The flow stabilizing plate is sleeved on the pre-mineralized pipe through the central circular hole. The flow stabilizing plate has gradually expanding holes from the central circular hole. The diameter of the central circular hole is 50-80cm. The inner layer of the gradually expanding holes is the smallest in diameter, which is 2-10mm, and the diameter ratio between adjacent layers is 1:1.2. A ore separator is installed at the junction of the cylindrical and conical parts of the trough. The upper part of the ore separator is conical, with the top of the cone 5-15cm away from the bottom outlet of the pre-mineralization pipe. The bottom of the cone passes through a disc with a thickness of 5-10mm. The opening pattern of the disc is the same as that of the flow stabilizer plate. The diameter of the disc is the same as the inner diameter of the cylindrical part of the trough. The center line of the upper opening of the cone coincides with the center line of the pre-mineralization pipe.

[0013] The method of applying the device includes the following steps: S1. Turn on the agitator of the mixing tank and feed the slurry at a uniform speed. At the same time, add different types of flotation reagents (conditioner, collector and frother) in sequence. After the mixing tank reaches the required liquid level, turn on the circulation pump to feed the slurry into the premineralization pipe. S2. Adjust the gas flow meter on the air inlet pipe to control the slurry level in the premineralization pipe to a distance of 50-200mm from the nozzle by controlling the air intake. S3. Adjust the valves of the middlings discharge port and the tailings discharge port to control the thickness of the foam layer and the flow rate of middlings and tailings; S4. Real-time sampling and testing of foam products. Stop operation when the ore loading of foam products is lower than the flotation requirements.

[0014] The ore in S3 is returned to the mixing tank for continued circulation.

[0015] The operation process of the device of this invention is as follows: stirring tank → circulating pump → pre-mineralization pipe (gas injection + eddy current mineralization) → column flotation tank (steady flow separation).

[0016] This invention, based on the principles of strong turbulent mineralization and weak turbulent flotation, designs a jet-vortex coupled pre-mineralization flotation device. The principle involves a circulating pump driving the slurry through a pre-mineralization pipe with a built-in vortex generator array, forming a 0.1-0.5 MPa high-pressure jet. Air is introduced using a self-priming Venturi structure and sheared by the high-speed slurry, generating controllable microbubbles of 10-1000 μm. In a high-intensity turbulent field with a Reynolds number Re > 4000, mineral particles collide with the bubbles at high frequencies. Then, based on the swirling effect generated by the vortex generator, the bubble-particle adhesion efficiency is increased by 20%-30%, achieving mineralization within 0.1-1.5 seconds before the slurry enters the flotation cell. This method not only effectively improves the collision and adhesion between particles and bubbles but also reduces the turbulence intensity of the mineralization bubble flotation environment, preventing the detachment of mineral particles from the surface of the mineralization bubbles.

[0017] The beneficial effects of the technical solutions provided by the embodiments of the present invention include at least the following: The above scheme adds a vortex generator device inside the premineralization tube, which, combined with the strong turbulent environment generated by the slurry jet, significantly improves the collision and adhesion effect between mineral particles and bubbles. A spiral guide vane is added to the end of the premineralization tube, allowing hydrophilic minerals to be classified into coarse and fine grades. A conical separator within the column flotation tank separates the hydrophilic minerals into coarse and fine grades. Based on the grade of the target minerals in the coarse and fine grades, the underflow is divided into middlings and tailings. A flow stabilizing plate is installed within the column flotation tank to reduce the turbulence intensity of the mineralization bubble flotation environment, effectively preventing the desorption of mineral particles from the surface of the mineralization bubbles. A middlings circulation system is added to the jet-vortex coupled premineralization flotation device, effectively improving the recovery rate of the target minerals. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a jet eddy current coupled pre-mineralization flotation device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the nozzle base structure in a jet vortex coupled pre-mineralization flotation device provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the premineralization tube structure in a jet vortex coupled premineralization flotation device provided in an embodiment of the present invention, wherein (a) is a conical vortex generator, (b) is a wedge-shaped vortex generator, and (c) is a spiral guide vane; Figure 4 This is a schematic diagram of the column flotation tank structure in a jet vortex coupled pre-mineralization flotation device provided in an embodiment of the present invention.

[0020] Wherein: 1-Agitator; 2-Circulating pump; 3-Gas flow meter; 4-Pressure gauge; 5-Nozzle base; 6-Nozzle; 7-Pre-mineralization pipe; 8-Overflow weir; 9-Foam product outlet; 10-Column flotation tank; 11-Flow stabilizer plate; 12-Ore separator; 13-Mid-flow discharge outlet; 14-Bottom flow discharge outlet; 15-Support; 16-Tank body; 51-Slurry inlet; 52-Air inlet; 53-Flange; 71-Conical vortex generator; 72-Wedge-shaped vortex generator; 73-Helical guide vane. Detailed Implementation

[0021] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0022] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0023] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0024] This invention provides a jet-vortex coupled pre-mineralization flotation device and method. For example... Figure 1 The schematic diagram shown is of a jet vortex coupled pre-mineralization flotation device, which includes:

[0025] 1. Mixing tank, 2. Circulating pump, 5. Nozzle base, 7. Pre-mineralization pipe, 10. Column float tank and 15. The mixing tank 1 is placed flat on the base of the support 15, and the circulation pump 2 is placed on the support partition above the mixing tank 1. The bottom of the premineralized pipe 7 extends into the column float trough 10, and the bottom outlet of the premineralized pipe is located in the lower middle position of the column float trough. The premineralized pipe 7 and the column float trough 10 are fixed to the support vertical rod by clamps. The inlet pipe of the circulating pump 2 extends into the mixing tank 1, and the outlet pipe of the circulating pump 2 is connected to the slurry inlet 51 of the nozzle base 5. The nozzle base 5 is sealed at the bottom and connected to the pre-mineralization tube 7. The nozzle base 5 is provided with an air inlet 52 on its side, and the air inlet 52 is connected to an air inlet pipe; Eddy current generators are evenly distributed inside the premineralized tube 7.

[0026] Pressure gauge 4 is installed on the outlet pipe of the circulating pump.

[0027] like Figure 2 The nozzle base includes a slurry inlet 51, a nozzle 6, an air inlet 52, and a flange 53. The flange 53 is located at the bottom of the nozzle base 5, and the nozzle base 5 is fixed to the top of the pre-mineralized pipe 7 by the flange 53. The top of the nozzle base 5 is a slurry inlet 51, which is connected to the nozzle 6 inside the nozzle base. The air inlet 52 is located in the middle of the side of the cylindrical nozzle base 5, and the bottom outlet of the nozzle 6 is flush with the axis of the air inlet 52. The nozzle base cylinder has 2-8 air inlets 52 evenly distributed on its side. In this embodiment, 4 air inlets are designed. A gas flow meter 3 is installed on the air inlet pipe connected to the air inlet.

[0028] like Figure 3 The inner wall of the premineralized pipe is inlaid with vortex generators. 2-8 vortex generators are evenly distributed in each layer around the inner wall of the premineralized pipe. The vortex generators in adjacent layers are staggered in the premineralized pipe with a distance of 5-20cm between layers. Spiral guide vanes 73 are installed at the bottom of the premineralized pipe.

[0029] The eddy current generator is a conical eddy current generator or a wedge-shaped eddy current generator, and the ratio of the length, width and height of the eddy current generator to the inner diameter of the premineralized pipe is 3:3:4:12. The diameter of the spiral guide vane is the same as the inner diameter of the premineralized pipe, the blade rotation is 90°-180°, and the height is 50-200mm.

[0030] like Figure 4 The column-floating trough includes an overflow weir 8, a trough body 16, a flow stabilizing plate 11, and a ore separator 12. The trough is a structure with a cylindrical upper part and a conical lower part. The ratio of the inner diameter of the trough to the height of the cylindrical part is 1:3, and the ratio of the height of the cone to the height of the cylinder is 1:5. The bottom of the cone has a bottom flow discharge port 14, and the side of the cone has a middlings discharge port 13 located two-thirds of the way from the bottom. The middlings discharge port is connected to the bottom outlet of the separator via a flexible hose.

[0031] The top of the tank 16 is an overflow weir 8, and the bottom of the overflow weir 8 has a foam product outlet 9. A flow stabilizing plate 11 is installed inside the tank 16 10-20cm above the bottom outlet of the premineralization pipe. The flow stabilizer plate 11 has a central circular hole, and gradually expanding holes are formed outward from the central circular hole. The diameter of the central circular hole is 50-80cm. The inner layer of the gradually expanding holes is the smallest in diameter, which is 2-10mm, and the diameter ratio between adjacent layers is 1:1.2. A ore separator 12 is installed at the junction of the cylindrical and conical parts of the trough. The upper part of the ore separator is conical, and the bottom of the cone passes through a disc. The disc is 5-10mm thick. The opening pattern of the disc is the same as that of the flow stabilizer plate. The diameter of the disc is the same as the inner diameter of the cylindrical part of the trough. The center line of the upper opening of the cone coincides with the center line of the pre-mineralization pipe.

[0032] The following description, in conjunction with specific embodiments, illustrates this point.

[0033] Example 1 This embodiment provides a jet eddy current coupled pre-mineralization flotation device and its application process.

[0034] This jet-vortex coupled pre-mineralization flotation device consists of a stirring tank, a circulating pump, a pre-mineralization tube, and a column flotation tank. The pre-mineralization tube is the core of the system, used to increase the collision and adhesion probability between mineral particles and air bubbles. The circulating pump feeds the slurry into the pre-mineralization tube in a jet manner. The pre-mineralization tube is divided into a particle-air bubble collision zone and an adhesion zone; this zone is the bubble-controlled mineralization zone, and its specific structure is as follows... Figure 1 As shown.

[0035] A copper mine in a foreign country has a fresh tailings with a copper grade of 0.12%. The tailings are diverted from the tailings pipeline to the mixing tank as flotation feed, and the slurry concentration is 300 kg / m³.

[0036] S1. While the fresh tailings from the concentrator are being diverted to the mixing tank, the agitator is turned on, and a peristaltic pump is used to add isopropyl xanthate and frother to the mixing tank at dosages of 10g / t and 5g / t, respectively.

[0037] S2. After ensuring the liquid level in the mixing tank is stable, turn on the circulation pump and adjust the circulation pump frequency to 0.2 MPa for the slurry jet pressure. By controlling the air inlet valve, stabilize the liquid level in the pre-mineralization pipe at a distance of 50-200 mm from the nozzle.

[0038] S3. The slurry that has been mineralized in the pre-mineralization pipe is fed into the column flotation tank through the spiral guide plate. The height of the foam layer is controlled by adjusting the middlings and underflow valves. After the system is running stably, the flotation foam product (concentrate) and underflow product (tailings) are sampled at the same time, once every 30 minutes. The three samples are mixed into one product.

[0039] Copper grade was determined in both concentrate and tailings products. Results: The copper grade in the reprocessing tailings decreased to 0.07%, while the copper grade in the concentrate remained above 1.0%.

[0040] Calculations show that after jet vortex coupled pre-mineralization flotation, the copper recovery rate of fresh tailings in the concentrator can reach over 20%. Combined with the concentrator's production indicators and the results of closed-circuit tests on tailings reprocessing concentrate in the laboratory, the copper recovery rate can be increased by more than 1 percentage point, and the recovery rate of ultrafine copper minerals can reach over 70%. Therefore, the device and method of this invention can effectively improve the copper recovery rate in the concentrator.

[0041] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A jet-vortex coupled pre-mineralization flotation device, characterized in that, The device includes: a mixing tank, a circulating pump, a nozzle base, a pre-mineralization pipe, a column float tank, and a support. The mixing tank is placed flat on the support base, and the circulation pump is placed on the support partition above the mixing tank. The bottom of the premineralized pipe extends into the column float tank, and the bottom outlet of the premineralized pipe is located in the lower middle position of the column float tank. The premineralized pipe and the column float tank are fixed to the support vertical rod by clamps. The inlet pipe of the circulating pump extends into the mixing tank, and the outlet pipe of the circulating pump is connected to the slurry inlet of the nozzle base. The nozzle base is sealed at the bottom with a pre-mineralization tube; The nozzle base is provided with an air inlet on its side, and the air inlet is connected to an air inlet pipe; The pre-mineralized tube contains uniformly distributed eddy current generators.

2. The jet eddy current coupled pre-mineralization flotation device according to claim 1, characterized in that, The circulating pump is a variable frequency multistage centrifugal pump with a flow rate range of 2-20 m³ / h. 3 / h, with a head of 20-60 m, the slurry jet pressure is changed by altering the frequency of the circulating pump; A pressure gauge is installed on the outlet pipe of the circulating pump.

3. The jet eddy current coupled pre-mineralization flotation device according to claim 1, characterized in that, The nozzle base includes a slurry inlet, a nozzle, an air inlet, and a flange. The flange is located at the bottom of the nozzle base, and the nozzle base is fixed to the top of the pre-mineralized pipe by the flange. The top of the nozzle base is a slurry inlet, which is connected to the nozzle inside the nozzle base; The air inlet is located in the middle of the side of the cylindrical nozzle base, and the bottom outlet of the nozzle is flush with the axis of the air inlet. The nozzle base cylinder has 2-8 air inlets evenly distributed on its side, and the air inlet pipe connected to the air inlet is equipped with a gas flow meter.

4. The jet eddy current coupled pre-mineralization flotation device according to claim 1, characterized in that, The inner wall of the premineralized pipe is embedded with vortex generators. 2-8 vortex generators are evenly distributed in each layer around the inner wall of the premineralized pipe. The vortex generators in adjacent layers are staggered in the premineralized pipe with a distance of 5-20cm between layers. Spiral guide vanes are installed at the bottom of the premineralized pipe.

5. The jet eddy current coupled pre-mineralization flotation device according to claim 3, characterized in that, The ratio of the inner diameter to the height of the nozzle base is 1:1.5, the inner diameter of the nozzle outlet is in the range of 3-12mm, the ratio of the inner diameter of the nozzle to the inner diameter of the nozzle base is in the range of 1:10 to 1:12, and the ratio of the inner diameter of the air inlet to the inner diameter of the nozzle base is 1:

15.

6. The jet eddy current coupled pre-mineralization flotation device according to claim 4, characterized in that, The eddy current generator is a conical eddy current generator or a wedge-shaped eddy current generator, and the ratio of the length, width and height of the eddy current generator to the inner diameter of the premineralized pipe is 3:3:4:

12. The diameter of the spiral guide vane is the same as the inner diameter of the premineralized pipe, the blade rotation is 90°-180°, and the height is 50-200mm.

7. The jet eddy current coupled pre-mineralization flotation device according to claim 1, characterized in that, The column-floating trough includes an overflow weir, a trough body, a flow stabilizer, and a ore separator. The trough is a structure with a cylindrical upper part and a conical lower part. The ratio of the inner diameter of the trough to the height of the cylindrical part is 1:3, and the ratio of the height of the cone to the height of the cylinder is 1:

5. The bottom of the cone has a bottom flow discharge port, and the side of the cone has a mid-flow discharge port located two-thirds of the way from the bottom. The mid-flow discharge port is connected to the bottom outlet of the separator via a flexible hose.

8. The jet eddy current coupled pre-mineralization flotation device according to claim 7, characterized in that, The top of the tank is an overflow weir, and the bottom of the overflow weir has an outlet for foam products. A flow stabilizing plate is installed inside the tank 10-20cm above the bottom outlet of the pre-mineralization pipe. The flow stabilizer plate has a central circular hole, which is then fitted onto the pre-mineralized pipe. The flow stabilizer plate has gradually expanding holes that extend outward from the central circular hole. The diameter of the central circular hole is 50-80 cm. The innermost layer of the gradually expanding holes, which is closest to the central circular hole, has the smallest diameter, which is 2-10 mm. The ratio of the diameters of adjacent holes is 1:1.

2. A ore separator is installed at the junction of the cylindrical and conical parts of the trough. The upper part of the ore separator is conical, with the top of the cone 5-15cm away from the bottom outlet of the pre-mineralization pipe. The bottom of the cone passes through a disc with a thickness of 5-10mm. The opening pattern of the disc is the same as that of the flow stabilizer plate. The diameter of the disc is the same as the inner diameter of the cylindrical part of the trough. The center line of the upper opening of the cone coincides with the center line of the pre-mineralization pipe.

9. The application method of the jet eddy current coupled pre-mineralization flotation device according to claim 1, characterized in that, The steps include the following: S1. Turn on the agitator of the mixing tank and feed the slurry at a uniform speed. At the same time, add different types of flotation reagents in sequence. After the mixing tank reaches the required liquid level, turn on the circulation pump to feed the slurry into the pre-mineralization pipe. S2. Adjust the gas flow meter on the air inlet pipe to control the slurry level in the premineralization pipe to a distance of 50-200mm from the nozzle by controlling the air intake. S3. Adjust the valves of the middlings discharge port and the tailings discharge port to control the thickness of the foam layer and the flow rate of middlings and tailings; S4. Real-time sampling and testing of foam products. Stop operation when the ore loading of foam products is lower than the flotation requirements.

10. The application method of the jet eddy current coupled pre-mineralization flotation device according to claim 9, characterized in that, The ore in S3 is returned to the mixing tank for continued circulation.

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