Sodium sulfate freezing continuous crystallization device

Abstract

The utility model provides a sodium sulfate freezing continuous crystallization device which is characterized in that a crystallizer comprises a crystallization chamber, a thickener comprises a thickener body, the top end of the thickener body is fixedly provided with a driving motor II, the lower end of the driving motor II is rotatably connected with a stirring shaft II, and the middle end of the top of the crystallization chamber is fixedly provided with a driving motor I; the bottom end of the first driving motor is rotationally connected with a first stirring shaft through a coupler, first rotating blades are installed on the first stirring shaft in a surrounding mode, a fixed shaft is fixedly installed at the bottom end of the first stirring shaft, a plurality of rotating plates are fixedly connected to the upper end and the lower end of the outer side of the second stirring shaft, and a plurality of stirring blades are fixedly connected to the middle end of the outer side of the second stirring shaft. The sodium sulfate freezing continuous crystallization device can achieve the effects of fully crystallizing materials, removing a sodium sulfate crystallization layer on the inner wall of the freezing crystallizer, avoiding scaling of the freezing crystallizer, enabling a thickener to discharge materials smoothly, ensuring that clear liquid is free of solid impurities and preventing crystallized materials from being attached to the inner wall of the thickener.

Description

Technical Field

[0001] The utility model relates to the technical field of continuous freezing and crystallization of sodium sulfate in wastewater in the gold smelting industry, and more specifically to a sodium sulfate freezing and continuous crystallization device. Background Art

[0002] The recovery of copper and cyanide from wastewater in the existing gold smelting field requires the addition of lime, chlorine alkali, acidification, SO2 and other methods. The treated wastewater still contains salts such as carbonates and sodium sulfate. The salinity of the wastewater increases over a long period of operation, affecting production efficiency and affecting the compliance with emission standards. Therefore, these discharged wastewaters need to be further treated.

[0003] In response to the above problems, after a lot of searching, we found a sodium sulfate freezing continuous crystallization device with patent number CN210993085U. This utility model adopts a shell and tube forced circulation heat exchanger and a cooling crystallizer for crystallization to prevent crystallization from clogging the equipment, and the equipment has a low failure rate.

[0004] The existing external circulation continuous freezing crystallization equipment does not have special components to enhance heat transfer outside the heat exchanger, making it difficult to improve heat transfer efficiency and cold capacity utilization; in addition, the pipeline between the heat exchanger and the crystallization chamber is too long, which can easily cause crystals to precipitate on the pipe wall, causing difficulty in material flow.

[0005] In response to the above problems, after a lot of searches, a continuous production double-circulation freezing crystallizer with patent number CN106823445A was found; this invention can realize continuous production of freezing crystallization, with high heat exchange efficiency and cold capacity utilization, and can effectively solve the problems of easy blockage of crystallizer pipes and long emptying and cleaning cycles. However, the technical solution provided by this patent does not have a stirring device, and the material cannot be quickly and fully crystallized. The freezing crystallization device is prone to scaling and adheres to the inner wall, which is not conducive to the removal of sodium sulfate in the long run.

[0006] The bottom of the existing thickener is prone to sedimentation, which leads to blockage of the discharge port.

[0007] In response to the above problems, after a lot of searches, we found a thickener for secondary washing of salt slurry with patent number CN213555513U; this utility model can scrape the inside of the thickener body and the first row of salt pipes to prevent the formation of hard scale and improve the utilization rate of the clear liquid. However, the technical solution provided by this patent may cause solid impurities in the clear liquid flowing into the overflow pipe, the upper end of the inner wall of the barrel cannot be scraped and hard scale is easily generated, the sediment is easily deposited in the conical bottom aggregate area, and the discharge is difficult and prone to blockage.

[0008] The utility model can make the material fully crystallize, remove the sodium sulfate crystal layer on the inner wall of the freezing crystallizer, avoid scaling of the freezing crystallizer, make the thickener discharge unobstructed, ensure that there are no solid impurities in the clear liquid, and prevent the crystallized material from adhering to the inner wall of the thickener. Utility Model Content

[0009] The utility model aims to solve the technical problems raised by the above-mentioned background technology and provides a sodium sulfate freezing continuous crystallization device.

[0010] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a sodium sulfate freezing continuous crystallization device, comprising: a feeding pump, a crystallizer, a cooling circulation pump, a refrigerant heat exchanger, a discharging pump, a thickener, a centrifuge, a mother liquor tank, a mother liquor pump, and a cyclone. The crystallizer includes a crystallization chamber, a discharge pipe is fixedly installed at the bottom end of the crystallization chamber, a material circulation pipe is connected to the lower end of the left side wall of the crystallization chamber, the upper pipe mouth of the material circulation pipe is connected to the top of the crystallization chamber, a material circulation pump is installed at the second 90-degree corner of the lower end of the material circulation pipe, a heat exchanger is fixedly installed above the material circulation pump, a guide tube is set in the middle of the crystallization chamber, the thickener includes a thickener body, and a drive motor is fixedly installed on the top of the thickener body. 2. The lower end of the driving motor 2 is rotatably connected to the stirring shaft 2, the bottom end of the thickener body is connected to a discharge pipe 1, the bottom right end of the discharge pipe 1 is connected to the discharge pipe 2, and the upper right end of the thickener body is connected to the overflow pipe. The top middle end of the crystallization chamber is fixedly installed with a driving motor 1, the bottom end of the driving motor 1 is rotatably connected to the stirring shaft 1 through a coupling, a rotating blade 1 is installed around the stirring shaft 1, the bottom end of the stirring shaft 1 is fixedly installed with a fixed shaft, and a number of connecting rods are fixedly installed on the fixed shaft, and a brush plate is installed at the end of the connecting rod, and a brush is provided on the brush plate. The upper and lower ends of the outer side of the stirring shaft 2 are fixedly connected to a number of rotating plates, and the outer middle end of the stirring shaft 2 is fixedly connected to a number of stirring blades.

[0011] A further preferred solution: the rotating blade 1 is a spiral-type rotating blade, the rotating blade 1 is hollow inside, the rotating blade 1 is connected to the stirring shaft 1 through a plurality of support rods, the support rods are fixed at the maximum diameter of the rotating blade 1, and the outer diameter of the rotating blade 1 is smaller than the inner diameter of the guide tube.

[0012] A further preferred solution is that the number of the connecting rods is 4, which are circumferentially distributed on the fixed shaft; the brush plate is an isosceles trapezoid; the rotating diameter of the brush plate is smaller than the inner diameter of the lower end of the crystallization chamber; the brush is in contact with the inner wall of the inverted terrace at the lower end of the crystallization chamber.

[0013] A further preferred solution: the number of the rotating plates is 8, the length of the rotating plate at the upper end of the second stirring shaft is different from that of the rotating plate at the lower end of the second stirring shaft, a scraper is fixedly installed on the end of the rotating plate away from the second stirring shaft, the scraper is in contact with the inner wall of the thickener body, a corner is provided in the middle of the scraper, and the number of the scrapers is 4.

[0014] A further preferred embodiment: the number of the stirring blades is 12, and the stirring blades are circumferentially distributed in three layers on the stirring shaft 2. The rotation diameter of the stirring blades distributed at the lower end of the stirring shaft 2 is smaller than the rotation diameter of the stirring blades distributed at the upper and middle ends of the stirring shaft 2, and the stirring blades form an angle of 75 degrees with the stirring shaft 2 toward the lower end.

[0015] A further preferred solution: a rotating blade 2 is installed around the lower end of the stirring shaft 2, and the diameter of the rotating blade 2 is the largest near the end of the rotating plate. The diameter of the rotating blade 2 gradually decreases along the stirring shaft 2 downward to the inlet of the discharge pipe 1, and the diameter of the rotating blade 2 remains unchanged inside the discharge pipe 1.

[0016] A further preferred solution is that a filter screen is provided on the left side of the overflow pipe, and the filter screen surrounds the inlet of the overflow pipe. The diameter of the filter screen is larger than the diameter of the overflow pipe, and the height of the overflow pipe is higher than the liquid outlet surface of the feed pipe at the upper left end of the thickener body.

[0017] Beneficial effects:

[0018] 1. A drive motor, a stirring shaft, a rotating blade, a support rod, a fixed shaft, a connecting rod, a brush plate and a brush are provided. When the material flows into the guide tube from the upper pipe opening of the material circulation pipe, the drive motor provides a rotational power to drive the stirring shaft to rotate, and the stirring shaft drives the support rod and the connecting rod to rotate, and the rotating blade and the brush plate also rotate accordingly, thereby achieving stirring of the material, accelerating the crystallization speed, making the material fully crystallized, and removing the sodium sulfate crystal layer on the inner wall of the freezing crystallizer to avoid scaling of the freezing crystallizer;

[0019] 2. By providing a rotating plate, a scraper, a stirring blade and a second rotating blade, when the drive motor is started, it drives the stirring shaft to rotate, causing the rotating plate, the stirring blade and the second rotating blade to rotate accordingly. The rotating plate in turn drives the scraper to rotate, which prevents the crystallized material from sticking to the inner wall of the thickener and ensures unobstructed discharge of the thickener;

[0020] 3. By setting up a filter screen, when the clear liquid after the material settles is discharged through the overflow pipe, the solid impurities mixed in the clear liquid are filtered out through the filter screen, effectively preventing the solid impurities mixed in the clear liquid from entering the next link and affecting the operation of the next link;

[0021] 4. In summary, the sodium sulfate freezing continuous crystallization device, by being provided with a drive motor 1, a stirring shaft 1, a rotating blade 1, a support rod, a fixed shaft, a connecting rod, a brush plate, a brush, a rotating plate, a scraper, a stirring blade, a rotating blade 2 and a filter screen, plays the role of fully crystallizing the material, removing the sodium sulfate crystal layer on the inner wall of the freezing crystallizer, avoiding scaling of the freezing crystallizer, making the thickener discharge unobstructed, ensuring that there are no solid impurities in the clear liquid and preventing the crystallized material from sticking to the inner wall of the thickener. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the crystallizer of the present utility model.

[0023] Figure 2 It is a structural schematic diagram of the thickener of the present utility model.

[0024] Figure 3 For the utility model Figure 2 Enlarged structural diagram at point A in the middle.

[0025] Figure 4 It is a partial enlarged structural diagram of the rotary blade 1 of the present invention.

[0026] Figure 5 It is a schematic diagram of the three-dimensional structure of the scraper of the present utility model.

[0027] Figure 1-5 In: 1-crystallization chamber, 2-discharge pipe, 3-material circulation pump, 4-material circulation pipe, 5-heat exchanger, 6-guide tube, 7-driving motor 1, 8-coupling, 9-stirring shaft 1, 10-rotating blade 1, 101-support rod, 11-fixed shaft, 12-connecting rod, 13-brush plate, 14-brush, 15-thickener body, 16-driving motor 2, 17-stirring shaft 2, 18-discharge pipe 1, 19-discharge pipe 2, 20-overflow pipe, 21-rotating plate, 22-scraper, 23-stirring blade, 24-rotating blade 2, 25-filter. DETAILED DESCRIPTION

[0028] The following is a combination of the appended examples of the present invention Figure 1-Figure 5 , clearly and completely describe the technical solutions in the embodiments of the present utility model.

[0029] See also Figure 1-5In the embodiment of the utility model, a sodium sulfate freezing continuous crystallization device includes: a feeding pump, a crystallizer, a cooling circulation pump, a refrigerant heat exchanger, a discharging pump, a thickener, a centrifuge, a mother liquor tank, a mother liquor pump, and a cyclone. The crystallizer includes a crystallization chamber 1, a discharge pipe 2 is fixedly installed at the bottom end of the crystallization chamber 1, a material circulation pipe 4 is connected to the lower end of the left side wall of the crystallization chamber 1, the upper pipe mouth of the material circulation pipe 4 is connected to the top of the crystallization chamber 1, a material circulation pump 3 is installed at the second 90-degree corner of the lower end of the material circulation pipe 4, a heat exchanger 5 is fixedly installed above the material circulation pump 3, a guide tube 6 is set in the middle of the crystallization chamber 1, the thickener includes a thickener body 15, a drive motor 2 16 is fixedly installed on the top of the thickener body 15, and the lower end of the drive motor 2 16 is rotated and connected It is connected to a stirring shaft 17, the bottom end of the thickener body 15 is connected to a discharge pipe 18, the bottom right end of the discharge pipe 19 is connected to a discharge pipe 2 19, and the upper right end of the thickener body is connected to an overflow pipe 20. A driving motor 7 is fixedly installed on the top middle end of the crystallization chamber 1, and the bottom end of the driving motor 7 is rotatably connected to a stirring shaft 9 through a coupling 8. A rotating blade 10 is installed around the stirring shaft 9, and a fixed shaft 11 is fixedly installed on the bottom end of the stirring shaft 9. A number of connecting rods 12 are fixedly installed on the fixed shaft 11, and a brush plate 13 is installed at the end of the connecting rod 12. A brush 14 is provided on the brush plate 13. The upper and lower ends of the outer side of the stirring shaft 2 17 are fixedly connected to a number of rotating plates 21, and the middle end of the outer side of the stirring shaft 2 17 is fixedly connected to a number of stirring blades 23.

[0030] In the embodiment of the present invention, the rotating blade 10 is a spiral-belt rotating blade. The rotating blade 10 is hollow inside. The rotating blade 10 is connected to the stirring shaft 9 through a number of support rods 101. The support rods 101 are fixed at the maximum diameter of the rotating blade 10. The outer diameter of the rotating blade 10 is smaller than the inner diameter of the guide tube 6. When the material flows into the guide tube 6 from the upper pipe mouth of the material circulation pipe 4, the stirring shaft 9 is driven to rotate by the driving motor 7, and the stirring shaft 9 drives the support rods 101 to rotate, and the rotating blade 10 also rotates accordingly, thereby achieving stirring of the material. The spiral-belt rotating blade will neither occupy too much position in the crystallization chamber 1 nor easily clog the material in the blade, and can accelerate the crystallization speed of the material.

[0031] In the embodiment of the present utility model, the number of connecting rods 12 is 4, which are circumferentially distributed on the fixed shaft 11. The brush plate 13 is an isosceles trapezoid. The rotating diameter of the brush plate 13 is smaller than the inner diameter of the lower end of the crystallization chamber 1. The brush 14 is in contact with the inner wall of the inverted terrace at the lower end of the crystallization chamber 1. When the driving motor 7 drives the stirring shaft 9 to rotate, the rotating blade 10 rotates accordingly to stir the material, and the fixed shaft 11 also drives the brush plate 13 to rotate accordingly through the connecting rod 12, thereby cleaning the sodium sulfate crystal layer on the inner wall of the lower end of the crystallization chamber 1 to prevent the entrance of the discharge pipe 2 from being blocked.

[0032] In the embodiment of the present invention, the number of rotating plates 21 is 8, and the length of the rotating plate 21 at the upper end of the stirring shaft 17 is different from that of the rotating plate 21 at the lower end of the stirring shaft 17. A scraper 22 is fixedly installed at the end of the rotating plate 21 away from the stirring shaft 17. The scraper 22 is in contact with the inner wall of the thickener body 15, and a corner is provided in the middle of the scraper 22. The number of scrapers 22 is 4. When the material flows into the thickener body 15 through the feed pipe at the upper left end of the thickener body 15, the stirring shaft 17 is driven to rotate by the driving motor 16, thereby driving the scraper 22 to rotate along the upper and lower inner walls of the thickener body 15 through the rotating plate 21. The area covered by the scraper 22 during rotation is large, thereby preventing high-viscosity materials from sticking to the wall to a large extent.

[0033] In the embodiment of the present invention, the number of stirring blades 23 is 12, and the stirring blades 23 are circumferentially distributed in three layers on the stirring shaft 17. The rotation diameter of the stirring blades 23 distributed at the lower end of the stirring shaft 17 is smaller than the rotation diameter of the stirring blades 23 distributed at the upper and middle ends of the stirring shaft 17. The stirring blades 23 form a 75-degree angle with the stirring shaft 17 toward the lower end. The spacing between the rotating plates 21 at the upper and lower ends of the stirring shaft 17 is large. When the material flows into the range between the rotating plates 21 at the upper and lower ends of the stirring shaft 17, the material cannot be stirred, which may cause the material to accumulate at the bottom end of the thickener body 15 and cause blockage. The inclined stirring blades 23 can both stir the material and make the material flow down along the inclined side of the stirring blades 23, preventing the material from remaining in the stirring blades 23 and affecting the next use of the thickener body 15.

[0034] In the embodiment of the present invention, a rotating blade 24 is installed around the lower end of the stirring shaft 17. The diameter of the rotating blade 24 is the largest at the end close to the turn plate 21. The diameter of the rotating blade 24 gradually decreases along the stirring shaft 17 downward to the entrance of the discharge pipe 18. The diameter of the rotating blade 24 remains unchanged in the discharge pipe 18. When the material flows into the bottom end of the thickener body 15 after stirring, the rotating blades 24 with different diameters are used to send the material from the bottom end of the thickener body 15 into the discharge pipe 18, and then from the discharge pipe 18 to the discharge pipe 2 19 inclined to the right, so as to prevent the material from accumulating in the discharge pipe 18.

[0035] In the embodiment of the present invention, a filter screen 25 is provided on the left side of the overflow pipe 20. The filter screen 25 surrounds the inlet of the overflow pipe 20. The diameter of the filter screen 25 is larger than the diameter of the overflow pipe 20. The height of the overflow pipe 20 is higher than the liquid outlet surface of the feed pipe at the upper left end of the thickener body 15. When the clear liquid after the material settles is discharged through the overflow pipe 20, the solid impurities mixed in the clear liquid are filtered out by the filter screen 25, so that the discharged clear liquid can be used for the next operation.

[0036] Working principle: The material enters the material circulation pipe 4 through the feed port on the material circulation pipe 4, contacts with a large amount of low-temperature circulating liquid in the material circulation pipe 4, and enters the top of the heat exchanger 5 together with the material circulation pump 3. The material after heat exchange and cooling enters the guide tube 6 in the crystallization chamber 1, and is driven by the driving motor 7 to drive the stirring shaft 9 to rotate, and the stirring shaft 9 drives the support rod 101 to rotate, and the rotating blade 10 and the brush plate 13 also rotate accordingly, thereby achieving the stirring of the material and removing the sodium sulfate crystal layer on the inner wall of the frozen crystallizer to avoid scaling of the frozen crystallizer. The precipitated grains settle downward, and the separation of the clear liquid and the slurry is achieved at the lower edge of the truncated cone guide tube 6, and the material containing crystals is removed. The material enters the discharge pump and then enters the cyclone. Part of the cyclone enters the thickener body 15, and the other part enters the crystallization chamber 1. The drive motor 2 16 on the thickener body 15 is started, and the rotational power provided by the drive motor 2 16 drives the stirring shaft 2 17 to rotate, so that the rotating plate 21, the stirring blade 23 and the rotating blade 2 24 also rotate. The rotating plate 21 drives the scraper 22 to rotate, which prevents the crystallized material from sticking to the inner wall of the thickener and ensures that the thickener discharges smoothly. The clear liquid in the thickener body 15 is filtered by the filter screen 25 and then flows out of the overflow pipe 20 and enters the centrifuge to centrifuge out sodium sulfate. The mother liquor enters the mother liquor tank and then enters the mother liquor pump and returns to the crystallizer.

Claims

1. A sodium sulfate freezing continuous crystallization device, comprising: A feeding pump, a crystallizer, a cooling circulation pump, a refrigerant heat exchanger, a discharging pump, a thickener, a centrifuge, a mother liquor tank, a mother liquor pump, and a cyclone. The crystallizer includes a crystallization chamber (1), characterized in that: a discharge pipe (2) is fixedly installed at the bottom end of the crystallization chamber (1), a material circulation pipe (4) is connected to the lower end of the left side wall of the crystallization chamber (1), the upper pipe mouth of the material circulation pipe (4) is connected to the top of the crystallization chamber (1), a material circulation pump (3) is installed at the second 90-degree corner of the lower end of the material circulation pipe (4), a heat exchanger (5) is fixedly installed above the material circulation pump (3), a guide tube (6) is set in the middle of the crystallization chamber (1), the thickener includes a thickener body (15), a driving motor 2 (16) is fixedly installed at the top of the thickener body (15), and the lower end of the driving motor 2 (16) is rotatably connected to the stirring shaft 2 (17), the thickener body (1 5) is connected to a discharge pipe 1 (18) at the bottom, a discharge pipe 2 (19) is connected to the right end of the bottom side of the discharge pipe 1 (18), an overflow pipe (20) is connected to the upper right end of the thickener body, a drive motor 1 (7) is fixedly installed at the top middle end of the crystallization chamber (1), the bottom end of the drive motor 1 (7) is rotatably connected to a stirring shaft 1 (9) through a coupling (8), and a rotating blade 1 (10) is installed around the stirring shaft 1 (9). The bottom end of the stirring shaft (9) is fixedly mounted with a fixed shaft (11), a plurality of connecting rods (12) are fixedly mounted on the fixed shaft (11), a brush plate (13) is mounted at the end of the connecting rod (12), and a brush (14) is provided on the brush plate (13), the upper and lower ends of the outer side of the stirring shaft (17) are fixedly connected with a plurality of rotating plates (21), and the middle end of the outer side of the stirring shaft (17) is fixedly connected with a plurality of stirring blades (23).

2. A sodium sulfate freezing continuous crystallization device according to claim 1, characterized in that: The rotating blade (10) is a spiral-belt rotating blade. The rotating blade (10) is hollow inside. The rotating blade (10) is connected to the stirring shaft (9) through a plurality of support rods (101). The support rods (101) are fixed at the maximum diameter of the rotating blade (10). The outer diameter of the rotating blade (10) is smaller than the inner diameter of the guide tube (6).

3. A sodium sulfate freezing continuous crystallization device according to claim 1, characterized in that: The number of the connecting rods (12) is four and they are circumferentially distributed on the fixed shaft (11). The brush plate (13) is in the shape of an isosceles trapezoid. The diameter of the brush plate (13) is smaller than the inner diameter of the lower end of the crystallization chamber (1). The brush (14) is in contact with the inner wall of the inverted terrace at the lower end of the crystallization chamber (1).

4. A sodium sulfate freezing continuous crystallization device according to claim 1, characterized in that: The number of the rotating plates (21) is 8. The length of the rotating plate (21) at the upper end of the second stirring shaft (17) is different from that of the rotating plate (21) at the lower end of the second stirring shaft (17). A scraper (22) is fixedly installed at one end of the rotating plate (21) away from the second stirring shaft (17). The scraper (22) is in contact with the inner wall of the thickener body (15). A corner is provided in the middle of the scraper (22). The number of the scraper (22) is 4.

5. A sodium sulfate freezing continuous crystallization device according to claim 1, characterized in that: The number of the stirring blades (23) is 12, and the stirring blades (23) are circumferentially distributed in three layers on the stirring shaft (17). The rotation diameter of the stirring blades (23) distributed at the lower end of the stirring shaft (17) is smaller than the rotation diameter of the stirring blades (23) distributed at the upper end and the middle end of the stirring shaft (17). The stirring blades (23) form an angle of 75 degrees with the stirring shaft (17) toward the lower end.

6. A sodium sulfate freezing continuous crystallization device according to claim 1, characterized in that: A rotating blade 2 (24) is mounted around the lower end of the stirring shaft 2 (17). The diameter of the rotating blade 2 (24) is the largest at one end close to the rotating plate (21). The diameter of the rotating blade 2 (24) gradually decreases along the stirring shaft 2 (17) downward to the inlet of the discharge pipe 1 (18). The diameter of the rotating blade 2 (24) remains unchanged inside the discharge pipe 1 (18).

7. A sodium sulfate freezing continuous crystallization device according to claim 1, characterized in that: A filter screen (25) is provided on the left side of the overflow pipe (20), and the filter screen (25) surrounds the inlet of the overflow pipe (20). The diameter of the filter screen (25) is larger than the diameter of the overflow pipe (20), and the height of the overflow pipe (20) is higher than the liquid outlet surface of the feed pipe at the upper left end of the thickener body (15).

Images