Process for producing ammonium paratungstate by treating scheelite with sulfuric acid

Abstract

The invention discloses a process for producing ammonium paratungstate by treating scheelite with sulfuric acid, and relates to the technical field of ammonium paratungstate production, the process comprises the following operation steps: S1, acid leaching decomposition: mixing scheelite powder with sulfuric acid by using mixing equipment, and reacting under normal pressure to dissolve tungsten in the form of phosphotungstic heteropolyacid to generate a tungsten-containing leachate; s2, purification and precipitation, wherein ammonium salt is added into the leachate to separate out ammonium phosphotungstate precipitate; s3, evaporative crystallization: concentrating and crystallizing the purified ammonium tungstate solution to obtain an ammonium paratungstate product; and S4, recovering by-products. According to the technology for producing ammonium paratungstate through sulfuric acid treatment of scheelite, the rotating pipe, the collecting box, the scraping strip and other structures are arranged, the pushing, scraping, cleaning and collecting effects are achieved at the same time, during mixing and stirring, the collecting box does not make continuous contact with the bottom of the mixing barrel, the scraping strip does not make continuous contact with the inner wall of the mixing barrel, abrasion is reduced, and the service life is prolonged. And the processing efficiency of the process for producing ammonium paratungstate by treating scheelite with sulfuric acid is improved.

Description

Technical Field

[0001] The invention relates to the technical field of ammonium paratungstate production, in particular to a process for producing ammonium paratungstate by treating scheelite with sulfuric acid. Background Art

[0002] Ammonium paratungstate is an inorganic compound with the appearance of monoclinic small transparent crystals or white crystals. Its aqueous solution is weakly acidic. When heated in air, it begins to remove some ammonia molecules below 100°C. When heated strongly, all ammonia molecules and crystal water are removed, and it turns into yellow tungsten trioxide powder.

[0003] In the production process of ammonium paratungstate, mixing equipment is required to mix scheelite powder with sulfuric acid. During mixing, residues are likely to remain on the inner wall of the mixing barrel. In the existing technology, this is usually cleaned manually. However, due to the certain depth of the mixing barrel, cleaning becomes more difficult and the efficiency needs to be improved.

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

[0005] The purpose of the present invention is to provide a process for producing ammonium paratungstate by treating scheelite with sulfuric acid, so as to solve the problem in the prior art that cleaning is usually performed manually, the mixing barrel has a certain depth, which increases the difficulty of cleaning and the efficiency of use needs to be improved.

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

[0007] S1. Acid leaching decomposition: Scheelite powder is mixed with sulfuric acid using a mixing device and reacted under normal pressure to dissolve tungsten in the form of phosphotungstic heteropoly acid to generate a tungsten-containing leachate;

[0008] The mixing device includes a mixing barrel, a rotating tube is provided inside the mixing barrel, a collecting box is provided at the bottom end of the rotating tube, and a scraper is provided on the side of the rotating tube. When the rotating tube moves downward, the collecting box abuts against the bottom of the mixing barrel, and at the same time drives the scraper to adhere to the inner wall of the mixing barrel;

[0009] S2. Purification and precipitation: ammonium salt is added to the leachate to precipitate ammonium phosphotungstate, which is then dissolved in ammonia water and then chemically precipitated to remove impurities;

[0010] S3, evaporation crystallization: the purified ammonium tungstate solution is concentrated and crystallized to obtain ammonium paratungstate product;

[0011] S4. By-product recovery: Separate the calcium sulfate or calcium fluoride in the leaching residue and recycle the tungsten resources in the mother liquor.

[0012] Preferably, a sliding column is provided for sliding inside the rotating tube, and the sliding column passes through the bottom end of the rotating tube, a fixed block is fixedly connected to the inner wall of the rotating tube, the bottom end of the fixed block is fixedly connected to a spring, the sliding column is fixedly connected to the bottom end of the spring, the collecting box is fixedly connected to the bottom end of the sliding column, a horizontal cylinder is fixedly connected to the side wall of the rotating tube, an air hole is opened on the side wall of the rotating tube, the rotating tube is connected to the horizontal cylinder through the air hole, a horizontal column is provided for sliding inside the horizontal cylinder, the horizontal column passes through one end of the horizontal cylinder away from the rotating tube, and the scraper cooperates with the horizontal column using a connecting assembly.

[0013] Preferably, the connecting assembly includes a circular shaft, a rotating block and a first torsion spring, the circular shaft is fixedly connected to the horizontal column, one end of the rotating block is fixedly connected to the scraper strip, the other end of the rotating block is rotatably connected to the circular shaft, and the first torsion spring is sleeved on the circular shaft.

[0014] Preferably, a square groove is opened on the side of the collection box, a round rod is fixedly connected to the inner wall of the collection box, a square plate is rotatably connected to the round rod, the square plate cooperates with the square groove, and a second torsion spring is mounted on the round rod.

[0015] Preferably, a scraper is fixedly connected to the bottom end of the side wall of the collecting box.

[0016] Preferably, a frame is provided on the outside of the mixing barrel, a guide rod is fixedly connected to the frame, a lifting frame is slidably provided on the guide rod, a first drive motor is installed on the lifting frame, and the rotating tube is fixedly connected to the drive shaft of the first drive motor.

[0017] Preferably, the top of the mixing barrel is equipped with a cover plate, the cover plate is provided with a through slot for the rotating pipe to pass through, a support frame is rotatably provided on the rotating pipe, and the support frame is fixedly connected to the top of the cover plate.

[0018] Preferably, a lead screw is rotatably provided on the frame, a threaded hole cooperating with the lead screw is provided on the lifting frame, and a first driving mechanism cooperating with the lead screw is provided on the top of the frame.

[0019] Preferably, a rotating shaft is rotatably provided on the lifting frame, a through hole for the rotating shaft to pass through is provided on the cover plate, a stirring ring is fixedly connected to the bottom end of the rotating shaft, the stirring ring cooperates with the scraper, and a second driving mechanism cooperating with the rotating shaft is provided on the lifting frame.

[0020] Preferably, universal wheels are installed at the four corners of the bottom of the mixing barrel.

[0021] Technical effects and advantages of the present invention:

[0022] 1. The present invention achieves the effects of pushing, scraping, cleaning, and collecting simultaneously by providing a rotating tube, a collecting box, and a scraping bar. During mixing and stirring, the collecting box does not continuously contact the bottom of the mixing barrel, and the scraping bar does not continuously contact the inner wall of the mixing barrel, thereby reducing wear and improving the processing efficiency of the process for producing ammonium paratungstate by treating scheelite with sulfuric acid.

[0023] 2. By setting up structures such as connecting components, the scraper strip produces a shaking effect, so that the residue on the scraper strip is shaken off;

[0024] 3. During mixing, the square groove is at the rear end of the collection box's rotation direction, and the square plate closes the square groove, so the raw materials will not enter the collection box at will. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a process flow chart of producing ammonium paratungstate by treating scheelite with sulfuric acid according to the present invention.

[0026] Figure 2 Schematic diagram of the structure of the mixing device of the present invention.

[0027] Figure 3 For the present invention Figure 2 A magnified schematic diagram of the structure in the middle.

[0028] Figure 4 It is a schematic diagram of the rotating tube and rotating shaft structure of the present invention.

[0029] Figure 5 For the present invention Figure 4 A magnified schematic diagram of the structure at point B in the middle.

[0030] Figure 6 For the present invention Figure 4 Enlarged schematic diagram of the structure at point C in the middle.

[0031] Figure 7 For the present invention Figure 4 Enlarged schematic diagram of the structure at point D in the middle.

[0032] Figure 8 This is a schematic diagram of the square plate and square groove structure of the present invention.

[0033] In the figure: 1. frame; 2. mixing barrel; 3. cover plate; 4. through groove; 5. rotating tube; 6. sliding column; 7. collecting box; 8. square plate; 9. scraper; 10. fixed block; 11. spring; 12. horizontal cylinder; 13. horizontal column; 14. circular shaft; 15. rotating block; 16. first torsion spring; 17. scraper; 18. air hole; 19. square groove; 20. round rod; 21. second torsion spring; 22. lifting frame; 23. guide rod; 24. screw; 25. first driving mechanism; 26. first driving motor; 27. second driving mechanism; 28. rotating shaft; 29. stirring ring; 30. universal wheel; 31. supporting frame; 32. magnetic block; 33. electromagnet; 34. fixing frame. DETAILED DESCRIPTION

[0034] The present invention provides Figures 1 to 8 The process for producing ammonium paratungstate by treating scheelite with sulfuric acid shown includes the following steps:

[0035] S1. Acid leaching decomposition: Scheelite powder is mixed with sulfuric acid using a mixing device and reacted under normal pressure to dissolve tungsten in the form of phosphotungstic heteropoly acid to generate a tungsten-containing leachate;

[0036] S2. Purification and precipitation: ammonium salt is added to the leachate to precipitate ammonium phosphotungstate, which is then dissolved in ammonia water and then chemically precipitated to remove impurities;

[0037] S3, evaporation crystallization: the purified ammonium tungstate solution is concentrated and crystallized to obtain ammonium paratungstate product;

[0038] S4. By-product recovery: Separate the calcium sulfate or calcium fluoride in the leaching residue and recycle the tungsten resources in the mother liquor.

[0039] Reference Figure 2 、 Figure 4 As shown in the figure, the mixing equipment includes a mixing barrel 2, a rotating tube 5 is provided inside the mixing barrel 2, a collecting box 7 is provided at the bottom end of the rotating tube 5, a square groove 19 is opened on the side of the collecting box 7, and a scraper 9 is fixedly connected to the bottom end of the side wall of the collecting box 7, and the scraper 9 and the square groove 19 are located on the same side of the collecting box 7; a scraper bar 17 is provided on the side of the rotating tube 5 for pushing and scraping to clean the bottom of the mixing barrel 2; a sliding column 6 is slidingly provided inside the rotating tube 5, and the sliding column 6 passes through the bottom end of the rotating tube 5, a fixed block 10 is fixedly connected to the inner wall of the rotating tube 5, and the bottom end of the fixed block 10 is fixedly connected to a spring 11, the sliding column 6 is fixedly connected to the bottom end of the spring 11, and the collecting box 7 is fixedly connected to the bottom end of the sliding column 6.

[0040] During specific use, a heating device (not shown in the figure) can be set outside the mixing barrel 2, including a heating barrel, a coil and other structures, so that during the mixing operation, the mixing barrel 2 is at a certain temperature to improve the mixing efficiency, which can be adjusted according to specific usage.

[0041] Reference Figure 2 、 Figure 4 、 Figure 6 As shown in the figure, a horizontal cylinder 12 is fixedly connected to the side wall of the rotating tube 5, and an air hole 18 is opened on the side wall of the rotating tube 5. The rotating tube 5 is connected to the horizontal cylinder 12 through the air hole 18; a horizontal column 13 is slidingly provided inside the horizontal cylinder 12, and the horizontal column 13 passes through the end of the horizontal cylinder 12 away from the rotating tube 5, and the scraper 17 cooperates with the horizontal column 13 using a connecting assembly.

[0042] When the interior of the mixing barrel 2 needs to be cleaned, the rotating tube 5 moves downward, and the collecting box 7 abuts against the bottom of the mixing barrel 2. At the same time, the collecting box 7 squeezes the sliding column 6 and retracts it into the interior of the rotating tube 5, pressing the gas inside the rotating tube 5 into the interior of the transverse cylinder 12, pushing the transverse column 13 to slide outward, so that the scraper 17 fits against the inner wall of the mixing barrel 2. The rotating tube 5 is controlled to rotate, driving the collecting box 7 and the scraper 17 to rotate synchronously, with the square groove 19 at the front end of the rotation direction of the collecting box 7; the scraper 17 pushes and scrapes the inner wall of the mixing barrel 2, and the residue falls to the bottom of the mixing barrel 2. The scraper 17 then pushes and scrapes the residue at the bottom of the mixing barrel 2, and the residue enters the interior of the collecting box 7 through the square groove 19, achieving the effect of pushing, scraping, cleaning and collecting at the same time.

[0043] In addition, during mixing and stirring, the collecting box 7 does not continuously contact the bottom of the mixing barrel 2, and the scraper 17 does not continuously contact the inner wall of the mixing barrel 2, thereby reducing wear.

[0044] Reference Figure 2 As shown in the figure, a frame 1 is provided on the outside of the mixing barrel 2, a guide rod 23 is fixedly connected to the frame 1, a lifting frame 22 is slidably provided on the guide rod 23, a first drive motor 26 is installed on the lifting frame 22, and a rotating tube 5 is fixedly connected to the drive shaft of the first drive motor 26. The first drive motor 26 drives the collecting box 7 and the scraper 17 to rotate synchronously through the rotating tube 5.

[0045] The top of the mixing drum 2 is fitted with a cover plate 3, which features a slot 4 for a rotating tube 5 to pass through. A support frame 31 is rotatably mounted on the rotating tube 5 and fixedly connected to the top of the cover plate 3. The rotating tube 5, support frame 31, and cover plate 3 can move up and down synchronously. A latch (not shown) can be installed between the cover plate 3 and the mixing drum 2 to prevent the cover plate 3 from rotating during mixing, but allow it to move up and down. Furthermore, the cover plate 3 is equipped with a main feed port and a closing plate for feeding.

[0046] A screw 24 is rotatably provided on the frame 1, a threaded hole is provided on the lifting frame 22 to cooperate with the screw 24, and a first driving mechanism 25 is provided on the top of the frame 1 to cooperate with the screw 24. The first driving mechanism 25 includes a motor and other structures for driving the screw 24 to rotate.

[0047] In actual use, the first driving mechanism 25 drives the screw 24 to rotate, and under the limiting action of the guide rod 23, the lifting frame 22 moves up and down. After the mixing is completed, the collection box 7, scraper 17 and other structures are pulled out from the inside of the mixing barrel 2 for easy cleaning.

[0048] Reference Figure 4As shown in FIG, a rotating shaft 28 is rotatably provided on the lifting frame 22, and a through hole for the rotating shaft 28 to pass through is provided on the cover plate 3. A stirring ring 29 is fixedly connected to the bottom end of the rotating shaft 28. The stirring ring 29 is provided with a protrusion on the outside. The stirring ring 29 cooperates with the scraper 17. A second driving mechanism 27 that cooperates with the rotating shaft 28 is provided on the lifting frame 22. The second driving mechanism 27 includes a motor, a belt, and other structures. During mixing, scheelite powder and sulfuric acid are poured into the interior of the mixing barrel 2. The second driving mechanism 27 drives the rotating shaft 28 to rotate, thereby driving the stirring ring 29 to rotate, stirring and mixing the scheelite powder and sulfuric acid.

[0049] Reference Figure 7 As shown in FIG, the connecting assembly includes a circular shaft 14, a rotating block 15, and a first torsion spring 16. The circular shaft 14 is fixedly connected to the horizontal column 13. One end of the rotating block 15 is fixedly connected to the scraper 17, and the other end of the rotating block 15 is rotatably connected to the circular shaft 14. The first torsion spring 16 is sleeved on the circular shaft 14. When the scraper 17 is not in contact with the inner wall of the mixing barrel 2, it is tilted.

[0050] The rotating tube 5 is controlled to move downward so that the scraper 17 contacts the inner wall of the mixing barrel 2, and the scraper 17 is adjusted from an inclined shape to a vertical shape. Then the rotating tube 5 is controlled to move upward so that the scraper 17 breaks contact with the inner wall of the mixing barrel 2, and the scraper 17 returns to an inclined shape. The reciprocating operation is repeated many times, and the scraper 17 produces a shaking effect, so that the residue on the scraper 17 is shaken off.

[0051] A round rod 20 is fixedly connected to the inner wall of the collecting box 7 , and a square plate 8 is rotatably connected to the round rod 20 . The square plate 8 cooperates with the square groove 19 , and a second torsion spring 21 is sleeved on the round rod 20 .

[0052] During mixing and stirring, the square groove 19 is at the rear end of the rotation direction of the collecting box 7, and the square plate 8 closes the square groove 19, so that the raw materials will not enter the interior of the collecting box 7 at will; during cleaning, the square groove 19 is at the front end of the rotation direction of the collecting box 7, and is squeezed by the residue, the square plate 8 flips, and the residue enters the interior of the collecting box 7 through the square groove 19.

[0053] Reference Figure 7 As shown in FIG, universal wheels 30 are installed at the four corners of the bottom of the mixing barrel 2 to facilitate the movement of the mixing barrel 2. A fixing bracket 34 is fixedly connected to the frame 1, and an electromagnet 33 is installed on the fixing bracket 34. A magnetic block 32 is fixedly connected to the mixing barrel 2. The magnetic block 32 cooperates with the electromagnet 33. When the mixing barrel 2 moves to a position below the cover plate 3, the electromagnet 33 is activated, and the magnetic properties of the side of the magnetic block 32 and the electromagnet 33 that are close to each other are controlled to be opposite. Under the action of the mutual attraction, the position of the mixing barrel 2 is fixed, ensuring the stability of mixing and stirring.

[0054] Working principle: During mixing and stirring, scheelite powder and sulfuric acid are poured into the interior of the mixing barrel 2, and the second driving mechanism 27 drives the rotating shaft 28 to rotate, thereby driving the stirring ring 29 to rotate, stirring and mixing the scheelite powder and sulfuric acid.

[0055] When the interior of the mixing barrel 2 needs to be cleaned, the rotating tube 5 moves downward, and the collecting box 7 abuts against the bottom of the mixing barrel 2. At the same time, the collecting box 7 squeezes the sliding column 6 and retracts it into the interior of the rotating tube 5, pressing the gas inside the rotating tube 5 into the interior of the transverse cylinder 12, pushing the transverse column 13 to slide outward, so that the scraper 17 fits against the inner wall of the mixing barrel 2. The rotating tube 5 is controlled to rotate, driving the collecting box 7 and the scraper 17 to rotate synchronously, with the square groove 19 at the front end of the rotation direction of the collecting box 7; the scraper 17 pushes and scrapes the inner wall of the mixing barrel 2, and the residue falls to the bottom of the mixing barrel 2. The scraper 17 then pushes and scrapes the residue at the bottom of the mixing barrel 2, and the residue enters the interior of the collecting box 7 through the square groove 19, achieving the effect of pushing, scraping, cleaning and collecting at the same time.

[0056] The first driving mechanism 25 drives the lead screw 24 to rotate, and under the limiting action of the guide rod 23, the lifting frame 22 moves up and down. After the mixing is completed, the collecting box 7, scraper 17 and other structures are pulled out from the inside of the mixing barrel 2 for easy cleaning.

Claims

1. A process for producing ammonium paratungstate by treating scheelite with sulfuric acid, characterized by: The following steps are included: S1. Acid leaching decomposition: Scheelite powder is mixed with sulfuric acid using a mixing device and reacted under normal pressure to dissolve tungsten in the form of phosphotungstic heteropoly acid to generate a tungsten-containing leachate; The mixing device comprises a mixing barrel (2), a rotating tube (5) is provided inside the mixing barrel (2), a collecting box (7) is provided at the bottom end of the rotating tube (5), and a scraper (17) is provided on the side of the rotating tube (5); when the rotating tube (5) moves downward, the collecting box (7) abuts against the bottom of the mixing barrel (2), and at the same time drives the scraper (17) to fit against the inner wall of the mixing barrel (2); S2. Purification and precipitation: ammonium salt is added to the leachate to precipitate ammonium phosphotungstate, which is then dissolved in ammonia water and then chemically precipitated to remove impurities; S3, evaporation crystallization: the purified ammonium tungstate solution is concentrated and crystallized to obtain ammonium paratungstate product; S4. By-product recovery: Separate the calcium sulfate or calcium fluoride in the leaching residue and recycle the tungsten resources in the mother liquor.

2. The process for producing ammonium paratungstate by treating scheelite with sulfuric acid according to claim 1, characterized in that: The rotating tube (5) is provided with a sliding column (6) for sliding inside, and the sliding column (6) passes through the bottom end of the rotating tube (5); a fixed block (10) is fixedly connected to the inner wall of the rotating tube (5); the bottom end of the fixed block (10) is fixedly connected to the spring (11); the sliding column (6) is fixedly connected to the bottom end of the spring (11); the collecting box (7) is fixedly connected to the bottom end of the sliding column (6); a transverse cylinder (12) is fixedly connected to the side wall of the rotating tube (5); an air hole (18) is provided on the side wall of the rotating tube (5); the rotating tube (5) is connected to the transverse cylinder (12) through the air hole (18); a transverse column (13) is provided inside the transverse cylinder (12) for sliding, and the transverse column (13) passes through one end of the transverse cylinder (12) away from the rotating tube (5); the scraper (17) cooperates with the transverse column (13) by using a connecting assembly.

3. The process for producing ammonium paratungstate by treating scheelite with sulfuric acid according to claim 2, characterized in that: The connecting assembly comprises a circular shaft (14), a rotating block (15) and a first torsion spring (16); the circular shaft (14) is fixedly connected to the transverse column (13); one end of the rotating block (15) is fixedly connected to the scraper strip (17); the other end of the rotating block (15) is rotatably connected to the circular shaft (14); and the first torsion spring (16) is sleeved on the circular shaft (14).

4. The process for producing ammonium paratungstate by treating scheelite with sulfuric acid according to claim 1, characterized in that: A square groove (19) is provided on the side of the collection box (7), a round rod (20) is fixedly connected to the inner wall of the collection box (7), a square plate (8) is rotatably connected to the round rod (20), the square plate (8) cooperates with the square groove (19), and a second torsion spring (21) is sleeved on the round rod (20).

5. The process for producing ammonium paratungstate by treating scheelite with sulfuric acid according to claim 1, characterized in that: A scraper (9) is fixedly connected to the bottom end of the side wall of the collecting box (7).

6. The process for producing ammonium paratungstate by treating scheelite with sulfuric acid according to claim 1, characterized in that: A frame (1) is provided outside the mixing barrel (2), a guide rod (23) is fixedly connected to the frame (1), a lifting frame (22) is slidably provided on the guide rod (23), a first drive motor (26) is installed on the lifting frame (22), and the rotating tube (5) is fixedly connected to the drive shaft of the first drive motor (26).

7. The process for producing ammonium paratungstate by treating scheelite with sulfuric acid according to claim 6, characterized in that: The top end of the mixing barrel (2) is matched with a cover plate (3), the cover plate (3) is provided with a through slot (4) for the rotating tube (5) to pass through, the rotating tube (5) is rotatably provided with a support frame (31), and the support frame (31) is fixedly connected to the top end of the cover plate (3).

8. The process for producing ammonium paratungstate by treating scheelite with sulfuric acid according to claim 7, characterized in that: A lead screw (24) is rotatably provided on the frame (1), a threaded hole cooperating with the lead screw (24) is provided on the lifting frame (22), and a first driving mechanism (25) cooperating with the lead screw (24) is provided on the top of the frame (1).

9. The process for producing ammonium paratungstate by treating scheelite with sulfuric acid according to claim 7, characterized in that: A rotating shaft (28) is rotatably provided on the lifting frame (22), a through hole for the rotating shaft (28) to pass through is provided on the cover plate (3), a stirring ring (29) is fixedly connected to the bottom end of the rotating shaft (28), and the stirring ring (29) cooperates with the scraper (17), and a second driving mechanism (27) is provided on the lifting frame (22) to cooperate with the rotating shaft (28).

10. The process for producing ammonium paratungstate by treating scheelite with sulfuric acid according to claim 1, characterized in that: Universal wheels (30) are installed at the four corners of the bottom of the mixing barrel (2).

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