Process for producing ammonium paratungstate by treating tungsten minerals with nitric acid

Abstract

The invention discloses a process for producing ammonium paratungstate by treating tungsten minerals with nitric acid, and relates to the technical field of ammonium paratungstate processing, the process comprises the following operation steps: S1, leaching: crushing, screening and removing impurities from tungsten mineral raw materials to obtain concentrate powder, and mixing the concentrate powder with a nitric acid solution for reaction by using a reaction kettle to obtain leachate and residues; and S2, filtering and separating: separating the leachate from residues through a filter press, and enabling the leachate to enter a subsequent treatment process. According to the technology for producing ammonium paratungstate by treating tungsten minerals with nitric acid, the inner wall of the centrifugal inner cylinder is arranged to be in a wavy shape, the effects of increasing centrifugal force, stabilizing particle distribution, evenly distributing mechanical stress and the like are achieved, the outer diameter of the cleaning ring can be adaptively changed according to the inner wall of the centrifugal inner cylinder, and the inner wall of the centrifugal inner cylinder is pushed and scraped in the vertical moving process; and meanwhile, in the outer diameter changing process of the cleaning ring, the arc pipe and the arc plate can swing back and forth, impurities can be conveniently shaken off, and the cleaning effect is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of ammonium paratungstate processing, in particular to a process for producing ammonium paratungstate by treating tungsten minerals with nitric acid. Background Art

[0002] Ammonium paratungstate is a chemical substance, mainly white crystals, in the form of flakes or needles. It is used to make tungsten trioxide or blue tungsten oxide to make metallic tungsten powder. It is also used to make ammonium metatungstate and other tungsten compounds, and is used as an additive in the petrochemical industry. With the continuous development of high-performance tungsten materials and tungsten alloys, the application prospects of high-purity ammonium paratungstate will be even broader. Therefore, the research on the preparation process of high-purity ammonium paratungstate has attracted people's attention.

[0003] In the process of producing ammonium paratungstate by treating tungsten minerals with nitric acid, centrifugal equipment is required to separate the crude ammonium paratungstate from the mother liquor. However, when the centrifugal equipment is used, solid materials tend to adhere to the inner wall of the inner cylinder and usually need to be manually handled using tools such as scrapers, which affects the separation efficiency.

[0004] Therefore, it is necessary to propose a process for producing ammonium paratungstate by treating tungsten minerals with nitric acid to solve the above problems. Summary of the Invention

[0005] The present invention aims to provide a process for producing ammonium paratungstate by treating tungsten minerals with nitric acid, so as to solve the problem that solid materials are easily attached to the inner wall of the inner cylinder when the centrifugal equipment is used, and usually need to be manually handled using tools such as scrapers, which affects the separation efficiency.

[0006] To achieve the above object, the present invention provides the following technical solution: a process for producing ammonium paratungstate by treating tungsten minerals with nitric acid, comprising the following steps:

[0007] S1. Leaching: The tungsten ore raw material is crushed, screened, and impurity-removed to obtain concentrate powder. The concentrate powder is mixed with nitric acid solution in a reactor to react to obtain leachate and residue;

[0008] S2, filtration separation: the leachate is separated from the residue by a filter press, and the leachate enters the subsequent processing process;

[0009] S3. Redox: Add a reducing agent to the leachate and react under stirring to reduce the high-valent tungsten ions in the leachate to low-valent tungsten ions to obtain a reduced solution;

[0010] S4, ion exchange: the reduced solution is passed through a strong acid cation exchange resin column to remove impurity ions and obtain a purified solution;

[0011] S5, precipitation crystallization: adding ammonia water to the purified liquid, standing in a crystallization kettle for crystallization to obtain crude ammonium paratungstate;

[0012] S6. Centrifugal separation: Separate the crude ammonium paratungstate from the mother liquor using centrifugal equipment, and obtain the finished ammonium paratungstate after drying the crude product;

[0013] The centrifugal device comprises a centrifugal outer cylinder with a centrifugal inner cylinder arranged therein, wherein the inner wall of the centrifugal inner cylinder is wavy along the vertical direction;

[0014] A cleaning ring for scraping the inner wall of the centrifugal inner cylinder is provided inside the centrifugal outer cylinder, and the outer diameter of the cleaning ring varies adaptively according to the inner wall of the centrifugal inner cylinder;

[0015] The cleaning ring is provided with elastic scraping strips for rotating and scraping the inner wall of the centrifugal inner cylinder.

[0016] Preferably, the cleaning ring includes an arc tube, a plurality of the arc tubes are provided, and an arc plate is slidably provided between two adjacent arc tubes.

[0017] Preferably, a sliding groove is provided on the inner wall of both ends of the arc tube, and a protrusion is slidably provided inside the sliding groove, and the protrusion is fixedly connected to the corresponding arc plate.

[0018] Preferably, a vertical rod is provided inside the cleaning ring, and an elastic telescopic rod is provided between the bottom end of the vertical rod and the arc tube, one end of the elastic telescopic rod is fixedly connected to the vertical rod, and the other end of the elastic telescopic rod is fixedly connected to the arc tube.

[0019] Preferably, a control mechanism cooperating with the vertical rod is provided above the cleaning ring, and the control mechanism includes an electric push rod and a first motor. The motor is fixedly connected to the telescopic end of the electric push rod, and the vertical rod is fixedly connected to the driving shaft of the motor.

[0020] Preferably, the top of the centrifugal outer cylinder is equipped with a cover plate, a square groove is formed through the cover plate, and the electric push rod is fixedly connected to the inner wall of the square groove.

[0021] Preferably, a circular groove is provided on the cover plate, a feed pipe is fixedly connected to the inside of the circular groove, and the feed pipe cooperates with the centrifugal inner cylinder.

[0022] Preferably, the bottom end of the centrifugal outer cylinder is connected to a discharge pipe.

[0023] Preferably, a driving mechanism for driving the centrifugal inner cylinder to rotate is provided at the bottom end of the centrifugal outer cylinder, and the driving mechanism includes a rotating arm, a first pulley, a bracket, a second motor, a second pulley and a belt.

[0024] Preferably, the centrifugal inner cylinder is provided with a plurality of through holes.

[0025] The technical effects and advantages of the present invention are as follows:

[0026] 1. The present invention achieves the effects of increasing centrifugal force, stabilizing particle distribution, and evenly distributing mechanical stress by setting the inner wall of the centrifugal inner cylinder in a wavy shape. The outer diameter of the cleaning ring can be adaptively changed according to the inner wall of the centrifugal inner cylinder. During the up and down movement, the inner wall of the centrifugal inner cylinder is pushed and scraped to assist the operator in cleaning. At the same time, during the change of the outer diameter of the cleaning ring, the arc tube and arc plate can swing back and forth to facilitate the shaking off of impurities and ensure the cleaning effect.

[0027] 2. The first motor drives the cleaning ring to rotate through the vertical rod and the elastic telescopic rod. The elastic scraper is attached to the inner wall of the centrifugal inner cylinder and rotates to push and scrape. Since the elastic scraper has a certain elasticity, the elastic scraper can adapt to the inner wall of the centrifugal inner cylinder to ensure the pushing and scraping effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a process flow chart of producing ammonium paratungstate by treating tungsten ore with nitric acid according to the present invention.

[0029] Figure 2 It is a schematic structural diagram of the centrifugal device of the present invention.

[0030] Figure 3 It is a structural schematic diagram of the centrifugal outer cylinder and the centrifugal inner cylinder of the present invention.

[0031] Figure 4 For the present invention Figure 3 A magnified schematic diagram of the structure in the middle.

[0032] Figure 5 This is a schematic diagram of the arc tube and arc plate structure of the present invention.

[0033] Figure 6 It is a schematic structural diagram of the vertical rod and the elastic telescopic rod of the present invention.

[0034] Figure 7 This is a schematic diagram of the vertical rod and arc tube structure of the present invention.

[0035] Figure 8 For the present invention Figure 7 Enlarged schematic diagram of the structure at point B in the middle.

[0036] In the figure: 1. Centrifugal outer cylinder; 2. Cover plate; 3. Centrifugal inner cylinder; 4. Cleaning ring; 401. Arc tube; 402. Arc plate; 403. Slide groove; 404. Bump; 5. Vertical rod; 6. Elastic telescopic rod; 7. Elastic scraper; 8. Square groove; 9. Electric push rod; 10. First motor; 11. Circular groove; 12. Feed pipe; 13. Discharge pipe; 14. Locking piece; 15. Rotating arm; 16. First pulley; 17. Bracket; 18. Second motor; 19. Second pulley; 20. Belt; 21. Through hole; 22. Base frame. DETAILED DESCRIPTION

[0037] The present invention provides Figures 1 to 8 The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid includes the following steps:

[0038] S1. Leaching: The tungsten ore raw material is crushed, screened, and impurity-removed to obtain concentrate powder. The concentrate powder is mixed with nitric acid solution in a reactor to react to obtain leachate and residue;

[0039] The concentrate powder is mixed with nitric acid solution in a mass ratio of 1:3 to 1:5, and reacted in a reactor at a temperature of 80°C to 100°C for 30 to 60 minutes;

[0040] S2, filtration separation: The leachate is separated from the residue by a filter press, and the leachate enters the subsequent processing process;

[0041] S3. Redox: Add a reducing agent to the leachate and react under stirring to reduce the high-valent tungsten ions in the leachate to low-valent tungsten ions to obtain a reduced solution;

[0042] wherein the reaction is carried out at a temperature of 60° C. to 80° C. for 15 to 30 minutes under stirring conditions;

[0043] S4, ion exchange: the reduced solution is passed through a strong acidic cation exchange resin column to remove impurity ions and obtain a purified solution;

[0044] S5, precipitation crystallization: adding ammonia water to the purified liquid, adjusting the pH value to 8 to 9, and standing in a crystallization kettle for crystallization to obtain crude ammonium paratungstate;

[0045] wherein the crystallization is allowed to stand in a crystallization kettle at a temperature of 40° C. to 60° C. for 24 to 48 hours;

[0046] S6. Centrifugal separation: Separate the crude ammonium paratungstate from the mother liquor using centrifugal equipment, and obtain the finished ammonium paratungstate after drying the crude product;

[0047] The centrifuge apparatus includes a centrifuge outer cylinder 1 with a centrifuge inner cylinder 3 disposed therein. A base frame 22 is fixedly connected to the bottom of the centrifuge outer cylinder 1. Multiple base frames 22 are provided, evenly distributed around the axis of the centrifuge outer cylinder 1. A cover plate 2 is fitted on the top of the centrifuge outer cylinder 1, and a lock 14 is provided between the cover plate 2 and the centrifuge outer cylinder 1. The lock 14 includes a latch and other structures. During centrifugal operation, the lock 14 secures the cover plate 2 to the centrifuge outer cylinder 1.

[0048] The centrifugal inner cylinder 3 is provided with a plurality of through holes 21 for the mother liquid to be thrown out and enter the position between the outer wall of the centrifugal inner cylinder 3 and the inner wall of the centrifugal outer cylinder 1 .

[0049] In order to improve the centrifugal effect, the inner wall of the centrifugal inner cylinder 3 is wavy along the vertical direction. Setting the inner wall of the centrifugal inner cylinder 3 to be wavy has the following effects:

[0050] Increase the centrifugal force: The wavy inner wall can increase the area of action of the centrifugal force, so that the solid material (crude ammonium paratungstate) adheres more tightly to the centrifugal inner cylinder 3 during the centrifugation process, thereby improving the separation efficiency;

[0051] Stable particle distribution: The wavy structure helps stabilize the distribution of solid materials, reduces the movement and redistribution of materials during centrifugation, and ensures the consistency of separation effect;

[0052] Reduce eddy currents and turbulence: The wavy inner wall can guide the flow of the mother liquid, reduce the generation of eddy currents and turbulence, make the mother liquid discharge more smoothly, and improve the separation speed and efficiency;

[0053] Improve particle morphology: The wavy structure helps maintain the shape of solid materials, reduce material breakage and deformation, and improve product quality;

[0054] Uniform distribution of mechanical stress: The wavy inner wall can evenly distribute the mechanical stress generated during the centrifugal process, reduce local stress concentration, and improve the stability and service life of the equipment;

[0055] Reduce vibration: The wavy structure helps reduce vibration during the centrifugal process, improve the smoothness of equipment operation, and reduce noise and equipment loss.

[0056] By setting the inner wall of the centrifugal inner cylinder 3 to be wavy, the effects of increasing centrifugal force, stabilizing particle distribution, and uniformly distributing mechanical stress can be achieved.

[0057] Taking into account that the inner wall of the centrifugal inner cylinder 3 is wavy in the vertical direction, in order to assist the operator in cleaning the inside of the centrifugal inner cylinder 3, a cleaning ring 4 for scraping the inner wall of the centrifugal inner cylinder 3 is provided inside the centrifugal outer cylinder 1. The cleaning ring 4 includes an arc tube 401. There are multiple arc tubes 401. An arc plate 402 is slidingly provided between two adjacent arc tubes 401. The end of the arc plate 402 is slidingly provided inside the corresponding arc tube 401. Since the arc plate 402 can slide inside the arc tube 401, the outer diameter of the cleaning ring 4 adapts to the inner wall of the centrifugal inner cylinder 3, thereby adapting to the wavy inner wall of the centrifugal inner cylinder 3.

[0058] In order to ensure the stability of the sliding of the arc plate 402 and prevent it from sliding out directly from the end of the arc tube 401, a sliding groove 403 is opened on the inner wall of both ends of the arc tube 401. A protrusion 404 is slidingly provided inside the sliding groove 403. The protrusion 404 is fixedly connected to the corresponding arc plate 402. When the arc plate 402 slides inside the arc tube 401, the protrusion 404 slides inside the sliding groove 403.

[0059] A vertical rod 5 is provided inside the cleaning ring 4, and an elastic telescopic rod 6 is provided between the bottom end of the vertical rod 5 and the arc tube 401. One end of the elastic telescopic rod 6 is fixedly connected to the vertical rod 5, and the other end of the elastic telescopic rod 6 is fixedly connected to the arc tube 401.

[0060] When the cleaning ring 4 is controlled to move downward by the vertical rod 5, when the cleaning ring 4 corresponds to the protruding portion of the inner wall of the centrifugal inner tube 3, the arc tube 401 moves toward the vertical rod 5 direction under the extrusion of the inner wall, and the elastic telescopic rod 6 contracts. At this time, the arc plate 402 is recovered to the inside of the arc tube 401, and the outer diameter of the cleaning ring 4 becomes smaller, which is convenient for scraping the protruding portion of the inner wall of the centrifugal inner tube 3; when the cleaning ring 4 corresponds to the concave portion of the inner wall of the centrifugal inner tube 3, the arc plate 402 is affected by the reset elastic force of the elastic telescopic rod 6, and the arc tube 401 moves and resets towards the principle vertical rod 5 direction. At this time, the part of the arc plate 402 that was originally recovered to the inside of the arc tube 401 slides out, and the arc plate 402 exposed to the outside recovers, and the outer diameter of the cleaning ring 4 becomes larger, which is convenient for scraping the concave portion of the inner wall of the centrifugal inner tube 3.

[0061] Since the outer diameter of the cleaning ring 4 can be adaptively changed according to the inner wall of the centrifugal inner cylinder 3, the inner wall of the centrifugal inner cylinder 3 is pushed and scraped during the up and down movement, thereby assisting the operator in cleaning.

[0062] In addition, during the change of the outer diameter of the cleaning ring 4, the arc tube 401 and the arc plate 402 can swing back and forth, so as to facilitate the shaking off of impurities and ensure the cleaning effect.

[0063] The cleaning ring 4 is provided with an elastic scraper 7 for rotating and scraping the inner wall of the centrifugal inner cylinder 3, and the elastic scraper 7 is fixedly connected to the arc tube 401. The elastic scraper 7 has a certain elasticity. In the initial state, the end of the elastic scraper 7 away from the arc tube 401 is tilted in the direction away from the axis of the cleaning ring 4.

[0064] A control mechanism cooperating with the vertical rod 5 is provided above the cleaning ring 4. The control mechanism includes an electric push rod 9 and a first motor 10. The first motor 10 is fixedly connected to the telescopic end of the electric push rod 9, and the vertical rod 5 is fixedly connected to the drive shaft of the first motor 10; a square groove 8 is opened through the cover plate 2, and the electric push rod 9 is fixedly connected to the inner wall of the square groove 8.

[0065] The electric push rod 9 drives the cleaning ring 4 to move up and down, and during this movement, the cleaning ring 4 pushes and scrapes the inner wall of the centrifugal inner cylinder 3. At the same time, the first motor 10 drives the cleaning ring 4 to rotate through the vertical rod 5 and the elastic telescopic rod 6, and the elastic scraping strip 7 is attached to the inner wall of the centrifugal inner cylinder 3 and rotates to scrape. Since the elastic scraping strip 7 has a certain degree of elasticity, the elastic scraping strip 7 can adapt to the inner wall of the centrifugal inner cylinder 3 to ensure a good scraping effect.

[0066] A circular groove 11 is provided on the cover plate 2, and a feed pipe 12 is fixedly connected to the inside of the circular groove 11, and the feed pipe 12 cooperates with the centrifugal inner cylinder 3; the bottom end of the centrifugal outer cylinder 1 is connected to a discharge pipe 13, which is used to feed the material and discharge the mother liquor from the discharge pipe 13.

[0067] The bottom end of the centrifugal outer cylinder 1 is provided with a driving mechanism for driving the centrifugal inner cylinder 3 to rotate, and the driving mechanism includes a rotating arm 15, a first pulley 16, a bracket 17, a second motor 18, a second pulley 19 and a belt 20. The rotating arm 15 is rotatably arranged at the bottom end of the centrifugal outer cylinder 1, the centrifugal inner cylinder 3 is fixedly connected to the top of the rotating arm 15, the first pulley 16 is fixedly connected to the bottom end of the rotating arm 15, the bracket 17 is fixedly connected to the outer wall of the centrifugal outer cylinder 1, the second motor 18 is fixedly connected to the top of the bracket 17, the second pulley 19 is fixedly connected to the drive shaft of the second motor 18, and the first pulley 16 and the second pulley 19 are connected by a belt 20.

[0068] Specifically, the second motor 18 drives the second pulley 19 to rotate. Since the first pulley 16 and the second pulley 19 are connected through the belt 20, the first pulley 16 drives the rotating arm 15 to rotate, and the rotating arm 15 drives the centrifugal inner cylinder 3 to realize centrifugal operation.

Claims

1. A process for producing ammonium paratungstate by treating tungsten minerals with nitric acid, characterized in that: The following steps are included: S1. Leaching: The tungsten ore raw material is crushed, screened, and impurity-removed to obtain concentrate powder. The concentrate powder is mixed with nitric acid solution in a reactor to react to obtain leachate and residue; S2, filtration separation: the leachate is separated from the residue by a filter press, and the leachate enters the subsequent processing process; S3. Redox: Add a reducing agent to the leachate and react under stirring to reduce the high-valent tungsten ions in the leachate to low-valent tungsten ions to obtain a reduced solution; S4, ion exchange: the reduced solution is passed through a strong acid cation exchange resin column to remove impurity ions and obtain a purified solution; S5, precipitation crystallization: adding ammonia water to the purified liquid, standing in a crystallization kettle for crystallization to obtain crude ammonium paratungstate; S6. Centrifugal separation: Separate the crude ammonium paratungstate from the mother liquor using centrifugal equipment, and obtain the finished ammonium paratungstate after drying the crude product; The centrifugal device comprises a centrifugal outer cylinder (1) in which a centrifugal inner cylinder (3) is arranged, and the inner wall of the centrifugal inner cylinder (3) is wavy along the vertical direction; A cleaning ring (4) for scraping the inner wall of the centrifugal inner cylinder (3) is provided inside the centrifugal outer cylinder (1), and the outer diameter of the cleaning ring (4) is adaptively changed according to the inner wall of the centrifugal inner cylinder (3); The cleaning ring (4) is provided with an elastic scraping strip (7) for rotating and scraping the inner wall of the centrifugal inner cylinder (3).

2. The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid according to claim 1, characterized in that: The cleaning ring (4) comprises an arc tube (401), a plurality of the arc tubes (401) are provided, and an arc plate (402) is slidably provided between two adjacent arc tubes (401).

3. The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid according to claim 2, characterized in that: Slide grooves (403) are provided on the inner walls of both ends of the arc tube (401), and protrusions (404) are slidably provided inside the slide grooves (403), and the protrusions (404) are fixedly connected to the corresponding arc plates (402).

4. The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid according to claim 2, characterized in that: A vertical rod (5) is provided inside the cleaning ring (4); an elastic telescopic rod (6) is provided between the bottom end of the vertical rod (5) and the arc tube (401); one end of the elastic telescopic rod (6) is fixedly connected to the vertical rod (5), and the other end of the elastic telescopic rod (6) is fixedly connected to the arc tube (401).

5. The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid according to claim 4, characterized in that: A control mechanism cooperating with the vertical rod (5) is provided above the cleaning ring (4), and the control mechanism comprises an electric push rod (9) and a first motor (10). The first motor (10) is fixedly connected to the telescopic end of the electric push rod (9), and the vertical rod (5) is fixedly connected to the drive shaft of the first motor (10).

6. The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid according to claim 5, characterized in that: The top of the centrifugal outer cylinder (1) is matched with a cover plate (2), a square groove (8) is penetrated through the cover plate (2), and the electric push rod (9) is fixedly connected to the inner wall of the square groove (8).

7. The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid according to claim 6, characterized in that: A circular groove (11) is provided on the cover plate (2), a feed pipe (12) is fixedly connected to the inside of the circular groove (11), and the feed pipe (12) cooperates with the centrifugal inner cylinder (3).

8. The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid according to claim 1, characterized in that: The bottom end of the centrifugal outer cylinder (1) is connected to a discharge pipe (13).

9. The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid according to claim 1, characterized in that: The bottom end of the centrifugal outer cylinder (1) is provided with a driving mechanism for driving the centrifugal inner cylinder (3) to rotate, and the driving mechanism includes a rotating arm (15), a first pulley (16), a bracket (17), a second motor (18), a second pulley (19) and a belt (20).

10. The process for producing ammonium paratungstate by treating tungsten minerals with nitric acid according to claim 1, characterized in that: The centrifugal inner cylinder (3) is provided with a plurality of through holes (21).

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