Multistage centrifugal washing device for vanadic acid leaching residue and residue washing process thereof

Abstract

The present application relates to a vanadic acid leaching residue multistage centrifugal washing device and a residue washing process thereof, and belongs to the technical field of solid-liquid separation of vanadium ore hydrometallurgy, comprising an outer cylinder, an inner centrifugal cylinder driven to rotate by a driving assembly is arranged in the inner cylinder, the inner centrifugal cylinder is divided into a first centrifugal cavity, a second centrifugal cavity and a third centrifugal cavity arranged in sequence from top to bottom by two groups of upper and lower partition plates, a plurality of liquid-permeable holes are formed on the outer wall of the inner centrifugal cylinder corresponding to each centrifugal cavity, and the washing assembly comprises a first washing part for washing the leaching residue in the second centrifugal cavity; the present application adopts a single-cylinder inner three-stage series centrifugal cavity to sequentially complete preliminary liquid throwing, intermediate staggered spray washing and final spray washing, the leaching residue liquid is separated and transported downward step by step by relying on the self weight and centrifugal force, the equipment has high integration degree, does not need to be arranged in series by multiple centrifugal machines, reduces the equipment floor area and reduces the equipment investment.

Description

Technical Field

[0001] This invention belongs to the field of solid-liquid separation technology in vanadium hydrometallurgy, specifically relating to a multi-stage centrifugal washing device for vanadium acid leaching residue and its washing process. Background Technology

[0002] Vanadium in vanadium ores often occurs isomorphously within layered silicate minerals such as illite, montmorillonite, kaolinite, chlorite, and mica. The Laojunya vanadium deposit is a representative example of carbonate-based coal-vanadium ores. The ore grade is 2.05%, and the main minerals are quartz (63.6%), mica (7.7%), potassium feldspar (6.4%), illite (5.0%), kaolinite (4.9%), dolomite (4.8%), montmorillonite (3.5%), chlorite (2.0%), and calcite (1.4%). The ore was crushed and ground to a particle size of -0.075 mm (92.31%), and a direct sulfuric acid leaching process was adopted: sulfuric acid dosage 60%, liquid-to-solid ratio 1.2:1, potassium chlorate 2% as oxidant, calcium fluoride 2% as fluorine-containing leaching aid, leaching temperature 95℃, stirring speed 400 r / min, leaching time 10 h; after acid leaching, vanadium-containing leachate and vanadium acid leaching residue were obtained.

[0003] The vanadate leaching residue produced by acid leaching has a high clay mineral content, and the internal pores of the residue adsorb a large amount of soluble vanadium salts, calcium sulfate, magnesium sulfate, and residual free sulfuric acid. Clay-type filter cakes are prone to cracking, channeling, and washing short-circuiting problems during the washing process. Conventional intermittent single-stage centrifuge washing has drawbacks such as high water consumption, incomplete elution of soluble vanadium, and low degree of automation. The existing intermittent washing method using a single centrifuge with multiple manual water additions, stirring, and centrifugation has the following main problems: ① Intermittent washing operations, low automation, long batch processing cycles, and high manual labor intensity; ② Clay filter cake is prone to cracking and channeling during washing, resulting in washing short circuits, incomplete leaching of soluble vanadium adsorbed on the slag surface and inside the pores, and high residual soluble vanadium in the leaching residue after washing, causing vanadium resource loss; ③ Multiple repeated washings consume a large amount of water, and the washing water is not graded and reused, resulting in high overall water consumption and a heavy load on subsequent wastewater treatment; ④ The washing filtrates from each stage are collected together, with the raw solution, intermediate washing water, and final washing wastewater mixed together. High-vanadium raw solution cannot be directly returned to the main vanadium extraction process, and medium- and low-vanadium washing water cannot be internally recycled and reused, resulting in serious waste of material and water resources. Therefore, a multi-stage centrifugal washing device and its washing process for vanadium acid leaching residue are needed. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-stage centrifugal washing device and its washing process for vanadate leaching residue that has high integration, good washing effect, and filtrate separation and reuse in order to solve the above problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] A multi-stage centrifugal washing device for vanadate leaching residue includes an outer cylinder containing an inner centrifuge cylinder driven to rotate by a drive assembly. The inner centrifuge cylinder is divided into a first centrifuge chamber, a second centrifuge chamber, and a third centrifuge chamber arranged sequentially from top to bottom by two sets of upper and lower baffles. Multiple liquid permeation holes are provided on the outer wall of the inner centrifuge cylinder corresponding to each centrifuge chamber. A lower discharge port for leaching residue flow is provided in the middle of each baffle to achieve progressive downward transfer of the leaching residue. The device also includes:

[0007] The washing assembly includes a first washing section for washing the residue in the second centrifuge chamber. The first washing section includes a third annular tube and a second annular tube arranged vertically. Multiple first nozzles are installed in an annular array on the tube bodies of the second annular tube and the third annular tube.

[0008] Adjacent first nozzles on the same annular tube are staggered along the axial direction. The two first nozzles that are vertically aligned are arranged in an inward or outward V-shape in the vertical direction, and the angle between the two vertically aligned first nozzles is 30-120°.

[0009] As a further optimization of the present invention, the distance between the liquid permeation hole at the bottom of the first centrifuge chamber and the upper partition is greater than the distance between the liquid permeation hole at the bottom of the second centrifuge chamber and the lower partition.

[0010] As a further optimization of the present invention, each of the partitions is provided with a lower discharge port for the flow of leaching residue at the middle.

[0011] As a further optimization of the present invention, a cavity is provided between the inner wall of the outer cylinder and the outer wall of the inner centrifuge cylinder, and a discharge device is provided in the cavity for discharging the liquid in the first centrifuge chamber and the second centrifuge chamber respectively.

[0012] As a further optimization of the present invention, the discharge component includes an annular plate fixed to the inner wall of the outer cylinder, the annular plate having a guide hole, and the bottom end of the guide hole being connected to an upper discharge pipe extending to the outside of the outer cylinder.

[0013] As a further optimization of the present invention, the bottom end of the outer wall of the outer cylinder is connected to a bottom drain pipe.

[0014] As a further optimization of the present invention, the washing assembly further includes a first annular tube disposed around the periphery of the third centrifugal chamber, wherein a plurality of second nozzles are installed in an annular array on the inner wall of the first annular tube.

[0015] As a further optimization of the present invention, the washing assembly further includes a four-way pipe, the three liquid outlets of which are respectively connected to a first annular pipe, a second annular pipe and a third annular pipe, the liquid inlet of which is connected to a water supply pipe, and a valve is installed on each liquid outlet of the four-way pipe.

[0016] As a further optimization of the present invention, the bottom end of the inner centrifuge cylinder is provided with a slag discharge pipe, and the top end of the outer cylinder is provided with a feeding hopper.

[0017] This invention also proposes a slag washing process, employing the aforementioned multi-stage centrifugal washing device for vanadate leaching slag, comprising the following steps:

[0018] S1. Vanadate leaching residue is fed into the inner centrifuge cylinder through the feeding hopper. The drive component drives the inner centrifuge cylinder to rotate at high speed. Under the action of centrifugal force, the leaching residue causes the leaching liquid to be distributed on the inner wall of the first centrifuge chamber, and the solid and liquid are initially separated. The filtrate enters the cavity through the liquid permeation hole and is discharged through the upper drain pipe.

[0019] S2. The leaching residue in the first centrifugal chamber falls into the second centrifugal chamber through the lower outlet in the middle of the partition, and continues to adhere to the wall of the second centrifugal chamber by centrifugal force.

[0020] S3. Open the valves on the four-way pipe corresponding to the second and third ring pipes. The washing water is sent into the four-way pipe through the water supply pipe and then distributed to the second and third ring pipes. The first nozzle sprays the residue in the second centrifuge chamber in a ring-shaped staggered manner for washing. Under the action of centrifugal force, the washing liquid passes through the liquid permeation hole and is discharged, completing the secondary solid-liquid separation.

[0021] S4. After washing, the leaching residue falls into the third centrifuge chamber through the lower outlet on the partition. The valve corresponding to the first annular pipe is opened, and the washing water is delivered to the first annular pipe. The second nozzle performs final spray washing on the leaching residue in the third centrifuge chamber. The washing filtrate passes through the liquid permeation hole and collects at the bottom of the outer cylinder, and is discharged through the bottom drain pipe.

[0022] S5. After the multi-stage washing is completed, the drive assembly is stopped, and the washed leaching residue in the third centrifuge chamber is discharged from the bottom slag discharge pipe, completing the entire vanadate leaching residue washing operation.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. This invention uses a single-cylinder body with three-stage series centrifuge chambers to sequentially complete the initial raw liquid removal, intermediate staggered spray washing, and final spray washing. The leaching residue is separated and transported downwards by gravity and centrifugal force. The equipment has a high degree of integration, does not require multiple centrifuges to be arranged in series, reduces the equipment footprint, and lowers equipment investment.

[0025] 2. In this invention, the second centrifugal chamber is equipped with two sets of annular tubes, one above the other. The nozzles are arranged in a staggered, inward / outward V-shape configuration, with fan-shaped atomizing nozzles impacting the clay leaching residue filter cake at multiple angles. This can effectively improve the problems of cracking, channeling, and short-circuiting during clay filter cake washing, increase the elution efficiency of soluble vanadium salts adsorbed inside the pores of the leaching residue, reduce the residual soluble vanadium in the leaching residue after washing, and reduce the loss of vanadium resources.

[0026] 3. In this invention, the high-vanadium raw liquid in the first centrifuge chamber is returned to the main vanadium extraction process; the intermediate washing filtrate in the second centrifuge chamber can be reverse-flowed back for use as washing makeup water; the low-vanadium final washing filtrate in the third centrifuge chamber is sent to wastewater treatment; a countercurrent washing process mode can be implemented, thereby reducing the consumption of fresh washing water and alleviating the pressure on subsequent wastewater treatment. Attached Figure Description

[0027] Figure 1 This is a cross-sectional structural schematic diagram of the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of the invention after the outer cylinder and the feeding hopper are removed;

[0029] Figure 3 This is a schematic diagram of the overall appearance structure of the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of the drive assembly, inner centrifuge cylinder, and washing assembly of the present invention;

[0031] Figure 5 This is a cross-sectional view of the inner centrifuge cylinder of the present invention;

[0032] Figure 6 This is a schematic diagram of the washing assembly of the present invention;

[0033] Figure 7 This is a top view of the outer cylinder, inner centrifuge cylinder, and partition of the present invention.

[0034] In the diagram: 1. Outer cylinder; 2. Feed hopper; 3. Bottom drain pipe; 4. Drive assembly; 41. Drive motor; 42. Belt connector; 5. Inner centrifuge cylinder; 51. First centrifuge chamber; 52. Second centrifuge chamber; 53. Third centrifuge chamber; 6. Baffle plate; 61. Lower outlet; 7. Liquid permeation hole; 8. Annular plate; 9. Upper drain pipe; 10. Washing assembly; 101. First annular pipe; 102. Second annular pipe; 103. Third annular pipe; 104. First nozzle; 105. Four-way pipe; 106. Water supply pipe; 107. Valve; 108. Second nozzle; 11. Slag discharge pipe; 12. Cavity. Detailed Implementation

[0035] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0036] Example 1: As Figures 1 to 7 As shown, this invention proposes a multi-stage centrifugal washing device for processing vanadium acid leaching residue produced from the direct acid leaching of Laojunya carbonate shale vanadium ore; the raw ore The grade is 2.05%, and the mineral composition is 63.6% quartz, 7.7% mica, 6.4% potassium feldspar, 5.0% illite, 4.9% kaolinite, 4.8% dolomite, 3.5% montmorillonite, 2.0% chlorite, and 1.4% calcite. The ore was ground to a particle size of 0.075 mm, accounting for 92.31%. The sulfuric acid content was 60%, the liquid-to-solid ratio was 1.2:1, 2% potassium chlorate was used as an oxidant, and 2% calcium fluoride was used as a fluorine-containing leaching aid. The leaching temperature was 95℃, the stirring speed was 400 r / min, and the leaching time was 10 h. After acid leaching, solid-liquid separation was performed to obtain vanadium acid leaching residue to be washed. The residue had a high clay mineral content and adsorbed soluble vanadium salts, calcium sulfate, magnesium sulfate, and free sulfuric acid.

[0037] This device specifically includes an outer cylinder 1, with a feeding hopper 2 installed at the top of the outer cylinder 1. The feeding hopper 2 is responsible for feeding the wet vanadate leaching residue after acid leaching. Inside the outer cylinder 1, there is an inner centrifuge cylinder 5 driven to rotate by a drive assembly 4. The inner centrifuge cylinder 5 rotates at high speed, relying on centrifugal force to complete solid-liquid separation. The bottom of the inner centrifuge cylinder 5 is equipped with a slag discharge pipe 11, through which the completely washed slag is finally discharged. The interior of the inner centrifuge cylinder 5 is divided into a first centrifuge chamber 51, a second centrifuge chamber 52, and a third centrifuge chamber 53 arranged sequentially from top to bottom by two sets of partitions 6. The second centrifuge chamber 52 and the third centrifuge chamber 53 are washing stations. The bottom of the feeding hopper 2 is connected to a feeding device. The discharge end of the feed pipe is not directly opposite the center of the partition 6, but close to the edge of the partition 6. Each partition 6 has a lower discharge port 61 for the flow of leaching residue in the middle, so as to realize the leaching residue is transferred downward in stages. The lower discharge pipe is connected to the bottom of the lower discharge port 61. The discharge end of the lower discharge pipe avoids the lower discharge port 61 below, so that the discharge end of the lower discharge pipe falls near the edge of the partition 6. This allows the wet leaching residue to fall directly to the partition 6 near the cylinder wall. Centrifugal force is used to quickly throw the leaching liquid out of the cylinder wall, avoiding the material from falling directly into the lower discharge port 61 and causing material cross-contamination. The leaching residue falls downward into the next centrifugal chamber by its own weight. Multiple liquid permeation holes 7 are opened on the outer wall of the inner centrifugal cylinder 5 of each centrifugal chamber.

[0038] like Figure 5 As shown, the distance H between the bottom liquid permeation hole 7 of the first centrifuge chamber 51 and the upper partition 6 is greater than the distance N between the bottom liquid permeation hole 7 of the second centrifuge chamber 52 and the lower partition 6. The material processed in the first centrifuge chamber 51 is a wet leaching residue with high water content after acid leaching. The material has a high liquid content, and a larger distance can reserve more liquid phase buffer space, reducing the probability that solid fine residue particles will be directly thrown out of the liquid permeation hole 7 under high-speed centrifugation conditions. The material in the second centrifuge chamber 52 and the third centrifuge chamber 53 has undergone preliminary dehydration and the water content has decreased. Therefore, the distance between the liquid permeation hole 7 and the partition 6 can be reduced to improve the utilization rate of the chamber space.

[0039] The aforementioned drive assembly 4 includes a drive motor 41 and a belt connector 42. The drive motor 41 drives the inner centrifuge cylinder 5 to rotate at high speed through the belt connector 42. The rotation speed can be adjusted according to the physical properties of the leaching residue.

[0040] The diameter of the liquid permeation hole 7 is set according to the particle size of the vanadate leaching residue. The diameter can be selected from 0.05 to 0.10 mm. A corrosion-resistant filter cloth liner can be fixedly installed on the inner wall of the inner centrifuge cylinder 5. The filter cloth is made of polypropylene cloth that is resistant to strong sulfuric acid corrosion. The filter cloth can block solid slag particles from passing through the liquid permeation hole 7 and only allow liquid phases such as leaching solution and washing filtrate to permeate outward, effectively preventing the loss of fine slag.

[0041] See Figure 1 and Figure 3 As shown, a cavity 12 is provided between the inner wall of the outer cylinder 1 and the outer wall of the inner centrifuge cylinder 5, so as not to interfere with the rotation of the inner centrifuge cylinder 5. The cavity 12 is provided with a discharge device for discharging the liquid in the first centrifuge chamber 51 and the second centrifuge chamber 52 respectively.

[0042] The discharge component includes an annular plate 8 fixed to the inner wall of the outer cylinder 1. The annular plate 8 has a guide hole, and the bottom end of the guide hole is connected to an upper drain pipe 9 extending to the outside of the outer cylinder 1. The raw liquid ejected from the first centrifuge chamber 51 and the intermediate washing filtrate ejected from the second centrifuge chamber 52 are intercepted and collected by the annular plate 8 and discharged outward through the guide hole and the upper drain pipe 9. The bottom end of the outer wall of the outer cylinder 1 is connected to a bottom drain pipe 3. The final washing filtrate ejected from the third centrifuge chamber 53 is collected downward to the bottom cavity of the outer cylinder 1 and discharged outward through the bottom drain pipe 3. The graded discharge can realize the collection of filtrate by quality. The raw liquid discharged from the first centrifuge chamber 51 can be returned to the main vanadium extraction process to recover vanadium. The intermediate washing filtrate from the second centrifuge chamber 52 can be recycled as pre-washing water. The final washing filtrate with low vanadium content from the third centrifuge chamber 53 is sent to wastewater for neutralization treatment, realizing the utilization of filtrate by quality and reducing the overall washing water consumption.

[0043] The discharge unit has two sets, one above the other. The upper discharge pipe 9 of the upper discharge unit is used to discharge the filtrate centrifuged from the first centrifuge chamber 51, and the upper discharge pipe 9 of the lower discharge unit is used to discharge the filtrate centrifuged from the second centrifuge chamber 52. The two streams of filtrate do not mix.

[0044] See Figure 1 - Figure 2 as well as Figure 4 - Figure 6As shown, the device also includes a washing assembly 10, which includes a first washing section for washing the leaching residue in the second centrifuge chamber 52. The first washing section includes a third annular tube 103 and a second annular tube 102 arranged vertically. Multiple first nozzles 104 are installed in an annular array on the tube bodies of the second annular tube 102 and the third annular tube 103. Two adjacent first nozzles 104 on the same annular tube are staggered along the axial direction. Two vertically aligned first nozzles 104 are arranged in an inward or outward V-shape in the vertical direction. One inward or outward V-shape constitutes a group. Two adjacent groups of first nozzles 104 are arranged alternately in the inward and outward V-shapes. The angle between two vertically aligned first nozzles 104 is 30-120°. The staggered nozzles and V-shaped spray structure allow the washing water to impact the clay-type leaching residue in the inner centrifuge chamber from multiple angles, which can improve the elution efficiency of soluble vanadium and sulfate adsorbed inside the filter cake.

[0045] The washing assembly 10 also includes a first annular tube 101 disposed around the third centrifugal chamber 53, and a plurality of second nozzles 108 are installed in an annular array on the inner wall of the first annular tube 101.

[0046] The washing assembly 10 also includes a four-way pipe 105. The three liquid outlets of the four-way pipe 105 are respectively connected to the first annular pipe 101, the second annular pipe 102 and the third annular pipe 103. The liquid inlet of the four-way pipe 105 is connected to a water supply pipe 106, and each liquid outlet of the four-way pipe 105 is equipped with a valve 107. Through each independent valve 107, the water supply on / off and water flow of the two-stage annular pipe of the second centrifugal chamber 52 and the first annular pipe 101 of the third centrifugal chamber 53 can be controlled respectively. The water supply medium can be process water. The entire washing assembly 10 can be made of Hastelloy corrosion-resistant material to resist the acid corrosion caused by vanadate leaching residue.

[0047] The first annular tube 101, the second annular tube 102, and the third annular tube 103 of the washing assembly 10 are all fixed to the inner wall of the outer cylinder 1 and do not rotate with the inner centrifugal cylinder 5. The first nozzle 104 and the second nozzle 108 spray washing water into the leaching residue from the outside to the inside in the direction of reverse centrifugal force through the liquid permeation hole 7 and the filter cloth liner. Since the high-speed rotation of the inner centrifugal cylinder 5 generates centrifugal hydraulic pressure, the external spray must overcome this pressure difference. According to the centrifugal hydraulic pressure formula ΔP=0.5×ρ×ω×(r2²−r1²) (ρ is the liquid density, ω is the angular velocity, and r is the radius), if the radius is set to 0.2m and the working speed is 1000-1500r / min, the centrifugal hydraulic pressure is about 0.1-0.35MPa. Therefore, the spray pressure is set to 0.3-1.0MPa (preferably 0.4-0.6MPa) to ensure that the jet can penetrate the filter cloth in the reverse direction.

[0048] As described above, in practical use, the leaching residue to be centrifuged and washed is added from the feeding hopper 2 and falls onto the partition 6. Under the action of high-speed centrifugal force, the leaching liquid is thrown out from the liquid permeation hole 7, and the leaching residue remains on the partition 6. After centrifugation for a period of time, the speed is reduced, the centrifugal force is reduced, and under the action of gravity separation, the leaching residue can slide through the lower discharge port 61 on the partition 6 and fall into the next centrifugal chamber. At this time, the speed is also increased to achieve centrifugal washing of this layer of centrifugal chamber. When the speed is reduced to allow the leaching residue after centrifugation at the top layer to fall, the leaching residue to be centrifuged and washed can be added from the feeding hopper 2 at the same time to replenish the upper centrifugal chamber. In this way, the continuous operation of the three layers of centrifugal chambers can be achieved, improving the centrifugal washing efficiency.

[0049] This invention also proposes a slag washing process, employing the aforementioned multi-stage centrifugal washing device for vanadium acid leaching slag. The material being processed is the vanadium acid leaching slag produced from the direct acid leaching of carbonate shale vanadium ore. The slag adsorbs soluble vanadium, calcium sulfate, magnesium sulfate, and free sulfuric acid, and includes the following steps:

[0050] S1. Vanadate leaching residue is fed into the inner centrifuge cylinder 5 through the feeding hopper 2. The driving component 4 drives the inner centrifuge cylinder 5 to rotate at high speed. Under the action of centrifugal force, the leaching residue causes the leaching liquid to be distributed on the inner wall of the first centrifuge chamber 51, and the solid and liquid are initially separated. The filtrate enters the cavity 12 through the liquid permeation hole 7 and is discharged through the upper drain pipe 9.

[0051] S2. After the solid-liquid separation in the first centrifuge chamber 51 is maintained for 2-5 minutes, the rotation speed is reduced or the valve at the lower discharge port 61 is opened. The leaching residue in the first centrifuge chamber 51 falls into the second centrifuge chamber 52 through the lower discharge port 61 in the middle of the partition 6 and continues to adhere to the cylinder wall of the second centrifuge chamber 52 by centrifugal force.

[0052] S3. Open the valve 107 on the four-way pipe 105 corresponding to the second annular pipe 103 and the third annular pipe 102. The washing water is sent into the four-way pipe 105 through the water supply pipe 106 and then diverted to the second annular pipe 103 and the third annular pipe 102. The first nozzle 104 performs annular staggered spray washing on the slag in the second centrifugal chamber 52. Under the action of centrifugal force, the washing liquid passes through the liquid permeation hole 7 and is discharged, completing the secondary solid-liquid separation.

[0053] S4. After washing, the leaching residue falls into the third centrifugal chamber 53 through the lower outlet 61 on the partition 6. The valve 107 corresponding to the first annular pipe 101 of the four-way pipe 105 is opened, and the washing water is delivered to the first annular pipe 101. The second nozzle 108 performs final spray washing on the leaching residue in the third centrifugal chamber 53. The washing filtrate passes through the liquid permeation hole 7 and collects at the bottom of the outer cylinder 1, and is discharged through the bottom drain pipe 3.

[0054] S5. After the multi-stage washing is completed, the drive component 4 is stopped, and the washed leaching residue in the third centrifugal chamber 53 is discharged from the bottom slag discharge pipe 11, completing the entire vanadate leaching residue washing operation.

[0055] In addition, an automated control unit is also provided, which is linked to drive motor 41, etc. Based on the online detection data of vanadium ion concentration and pH of the filtrate flowing out of the upper drain pipe 9 and the bottom drain pipe 3, the washing time of each chamber, the opening of the water supply valve 107, and the washing water pressure are automatically adjusted; when the concentration of soluble vanadium ions in the filtrate is detected to drop to the set threshold, it is determined that the washing of that chamber meets the standard.

[0056] The design of the upper and lower outlets 61 of the aforementioned partition 6 can be explained in the following detail:

[0057] Implementation Method 1: The lower discharge port 61 is preferably funnel-shaped with an arc transition at the upper opening. The baffle 6 gradually slopes upward from the center to the surrounding area at an angle of 5-10°, making the center low so that the leaching residue can slide down after the centrifugal force decreases. The lower discharge port 61 can be in a normally open state without a valve. At this time, under the action of a large centrifugal force, more liquid of the added leaching residue moves outward and is discharged. More leaching residue can be discharged through the lower discharge port 61 to the next centrifuge chamber, thus realizing a three-stage continuous feeding centrifugation operation.

[0058] Implementation Method 2: An openable gate can be installed at the lower outlet 61. The gate is closed during the centrifugation operation and opened after the solid-liquid separation in this chamber is completed. Considering that the inner centrifuge cylinder 5 needs to rotate, it would be difficult to achieve this if the valve rotates with it. In this case, the gate body (gate plate, rotating shaft, seal) can be considered to rotate together with the inner centrifuge cylinder 5 and the partition 6. However, the driving power source (motor / swing cylinder) is fixed on the outer cylinder 1 and does not rotate, and does not rotate with the cylinder. The power is transmitted through the cylinder wall via magnetic coupling (magnetic coupling) to transmit torque.

[0059] Specifically, 1. Each lower discharge port 61 is equipped with a rotating corrosion-resistant gate plate. The gate plate is hinged and installed at the lower discharge port 61 position of the partition 6. The gate plate and the rotating shaft rotate synchronously with the partition 6 and the inner centrifuge 5. The inner end of the gate plate rotating shaft is fixedly connected to the built-in permanent magnet (inner magnetic rotor), and the whole is located in the acidic medium space inside the inner centrifuge.

[0060] 2. On the inner centrifuge cylinder 5, at the radially outer position corresponding to each gate shaft, a thin-walled, non-magnetic Hastelloy alloy isolation sleeve is made on the cylinder wall (non-magnetic, acid-resistant, completely isolates the inner and outer cavities, without openings, and without shafts passing through the cylinder wall); an outer magnetic rotor is arranged on the outer side of the isolation sleeve (inside cavity 12, belonging to the outer cylinder 1 side, a static space). The outer magnetic rotor is driven by a swing angle servo motor / swing cylinder that is stationary on the inner wall of the outer cylinder 1. The outer magnetic rotor is a stationary mechanism and does not rotate with the inner centrifuge cylinder.

[0061] Working principle: When the inner centrifuge drum 5 rotates at high speed, the inner magnetic rotor (rotating with the drum) and the outer magnetic rotor (stationary) rotate relative to each other. When it is necessary to switch the gate opening / closing state, the speed of the inner centrifuge drum is reduced to a low speed (100-400r / min). At this time, the inner and outer magnetic rotors are magnetically coupled and meshed. The external stationary pendulum motor rotates at a set angle, and the magnetic force drives the gate shaft inside the drum to rotate through the thin-walled isolation sleeve, completing the gate opening / closing action. After the action is completed, the external motor returns to its original position, and the centrifuge operating speed is increased again.

[0062] The gate switch is activated only at low speeds; during the high-speed centrifugal washing stage, the gate does not operate, and the inner and outer magnets are allowed to slip relative to each other without interfering with the high-speed rotation of the inner cylinder.

[0063] Example 2: Processing vanadium acid leaching residue from carbonate shale vanadium ore using a combined beneficiation-leaching process; the raw ore is subjected to low-shear desliming screening using a wet desliming screening drum; the undersize slurry is adjusted and dispersed under high shear to adjust the total concentration of Ca²⁺ and +Mg²⁺ to 40-100 mg / L; weak anionic polyacrylamide is added for selective sedimentation to obtain vanadium-containing clay overflow and underfill; the underfill is washed and deagglomerated, and then residual vanadium in the underfill is recovered by flotation; the overflow, washed overflow, and flotation vanadium concentrate are combined to obtain a comprehensive vanadium concentrate; the comprehensive vanadium concentrate is pre-acidified and degassed, and then an oxidant and a fluorine-containing leaching aid, sulfuric acid, are added to enhance acid leaching; solid-liquid separation yields vanadium acid leaching residue to be washed.

[0064] The slag washing process adopts a counter-current washing mode: fresh washing water is only supplied to the third centrifuge chamber 53; after the final washing filtrate produced by the third centrifuge chamber 53 is simply filtered to remove fine residue, it is used as the washing water supply for the second centrifuge chamber 52, and no additional large amount of fresh water is introduced into the second centrifuge chamber 52; the remaining process operation, speed, time, and nozzle pressure parameters are the same as in Example 1.

[0065] Through the countercurrent washing mode, under the same washing standards, the consumption of fresh washing water can be reduced compared to using all fresh water; the high vanadium raw solution in the first centrifuge chamber 51 is returned to the leaching process of the sorting-leaching combined process; the intermediate washing water in the second centrifuge chamber 52 is internally circulated; a small amount of final washing filtrate in the third centrifuge chamber 53 is sent to wastewater treatment; the leaching residue has a high adsorption and elution rate of soluble vanadium, and the soluble vanadium residue in the leaching residue is reduced.

[0066] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A multi-stage centrifugal washing device for vanadate leaching residue, comprising an outer cylinder (1), wherein an inner centrifugal cylinder (5) is provided inside which is driven to rotate by a drive assembly (4), characterized in that, The inner centrifuge cylinder (5) is divided into a first centrifuge chamber (51), a second centrifuge chamber (52), and a third centrifuge chamber (53) arranged sequentially from top to bottom by two sets of upper and lower partitions (6). Multiple liquid permeation holes (7) are provided on the outer wall of the inner centrifuge cylinder (5) corresponding to each centrifuge chamber. A lower discharge port (61) for the leaching residue is provided in the middle of the partition (6) to achieve the step-by-step downward transfer of the leaching residue. The system also includes: The washing assembly (10) includes a first washing section for washing the leaching residue in the second centrifuge chamber (52). The first washing section includes a third annular tube (103) and a second annular tube (102) arranged vertically. Multiple first nozzles (104) are installed in an annular array on the tube bodies of the second annular tube (102) and the third annular tube (103). The adjacent first nozzles (104) on the same annular tube are staggered along the axial direction. The two first nozzles (104) that are aligned vertically are arranged in an inward or outward V-shape in the vertical direction, and the angle between the two first nozzles (104) that are aligned vertically is 30-120°.

2. The multi-stage centrifugal washing device for vanadate leaching residue according to claim 1, characterized in that, The distance between the liquid permeation hole (7) at the bottom of the first centrifuge chamber (51) and the adjacent partition (6) is greater than the distance between the liquid permeation hole (7) at the bottom of the second centrifuge chamber (52) and the adjacent partition (6) below it.

3. The multi-stage centrifugal washing device for vanadate leaching residue according to claim 1, characterized in that, Each of the aforementioned partitions (6) has a lower discharge port (61) in the middle for the flow of leaching residue.

4. The multi-stage centrifugal washing device for vanadate leaching residue according to claim 1, characterized in that, A cavity (12) is provided between the inner wall of the outer cylinder (1) and the outer wall of the inner centrifuge cylinder (5). The cavity (12) is provided with a discharge device for discharging the liquid in the first centrifuge chamber (51) and the second centrifuge chamber (52) respectively.

5. The multi-stage centrifugal washing device for vanadate leaching residue according to claim 4, characterized in that, The discharge component includes an annular plate (8) fixed to the inner wall of the outer cylinder (1), and a guide hole is provided on the annular plate (8). The bottom end of the guide hole is connected to an upper discharge pipe (9) extending to the outside of the outer cylinder (1).

6. The multi-stage centrifugal washing device for vanadate leaching residue according to claim 4, characterized in that, The bottom of the outer wall of the outer cylinder (1) is connected to a bottom drain pipe (3).

7. The multi-stage centrifugal washing device for vanadate leaching residue according to claim 1, characterized in that, The washing assembly (10) also includes a first annular tube (101) disposed around the third centrifugal chamber (53), and a plurality of second nozzles (108) are installed in an annular array on the inner wall of the first annular tube (101).

8. The multi-stage centrifugal washing device for vanadate leaching residue according to claim 7, characterized in that, The washing assembly (10) also includes a four-way pipe (105), the three liquid outlets of which are connected to the first annular pipe (101), the second annular pipe (102) and the third annular pipe (103) respectively. The liquid inlet of the four-way pipe (105) is connected to a water supply pipe (106), and a valve (107) is installed on each liquid outlet of the four-way pipe (105).

9. The multi-stage centrifugal washing device for vanadate leaching residue according to claim 1, characterized in that, The bottom end of the inner centrifuge cylinder (5) is provided with a slag discharge pipe (11), and the top end of the outer cylinder (1) is provided with a feeding hopper (2).

10. A slag washing process, employing the multi-stage centrifugal washing device for vanadate leaching slag as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Vanadate leaching residue is fed into the inner centrifuge cylinder (5) through the feeding hopper (2). The driving component (4) drives the inner centrifuge cylinder (5) to rotate at high speed. Under the action of centrifugal force, the leaching residue is distributed on the inner wall of the first centrifuge chamber (51), and the solid and liquid are initially separated. The filtrate enters the cavity (12) through the liquid permeation hole (7) and is discharged through the upper drain pipe (9). S2. The leaching residue in the first centrifugal chamber (51) falls into the second centrifugal chamber (52) through the lower discharge port (61) in the middle of the partition (6), and continues to adhere to the cylinder wall of the second centrifugal chamber (52) by centrifugal force. S3. Open the valve (107) on the four-way pipe (105) corresponding to the second ring pipe (102) and the third ring pipe (103). The washing water is sent into the four-way pipe (105) through the water supply pipe (106) and then diverted to the second ring pipe (103) and the third ring pipe (102). The first nozzle (104) sprays the residue in the second centrifuge chamber (52) in a ring-shaped staggered spray and washes it. Under the action of centrifugal force, the washing liquid passes through the liquid permeation hole (7) and is discharged, completing the secondary solid-liquid separation. S4. After washing, the leaching residue falls into the third centrifuge chamber (53) through the lower outlet (61) on the partition (6). The valve (107) of the four-way pipe (105) corresponding to the first ring pipe (101) is opened, and the washing water is delivered to the first ring pipe (101). The second nozzle (108) performs the final spray washing on the leaching residue in the third centrifuge chamber (53). The washing filtrate passes through the liquid permeation hole (7) and collects at the bottom of the outer cylinder (1), and is discharged through the bottom drain pipe (3). S5. After the multi-stage washing is completed, the drive assembly (4) is stopped, and the washed leaching residue in the third centrifugal chamber (53) is discharged from the bottom slag discharge pipe (11), completing the entire vanadate leaching residue washing operation.

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