Flocculant-free high-temperature sedimentation equipment

Abstract

The utility model discloses flocculant-free high-temperature settling equipment, which belongs to the technical field of high-temperature settling and comprises a settling tank, and a central feeding well is arranged in the settling tank. A plurality of nozzles are distributed on the edge of the central feeding well, and each nozzle is connected with a feeding pipe; a feeding hole extending out of the side part of the settling tank is formed in the outer end of the feeding pipe; the center of the settling tank is connected with a stirring shaft, and the stirring shaft extends to the lower part of the settling tank through the central feeding well; the lower end of the stirring shaft is connected with a raking machine; and the stirring shaft is connected with a conical fluid director below the bottom opening position of the central feeding well. The device disclosed by the utility model can directly and quickly settle without temperature and pressure reduction operation and addition of settling promoters such as a flocculating agent and the like, so that the production cost is reduced, the organic flocculating agent is prevented from entering a production system to cause organic matters to pollute production materials, and the energy consumption is reduced.

Description

Technical Field

[0001] The utility model relates to a flocculant-free high-temperature sedimentation device, belonging to the technical field of high-temperature sedimentation. Background Art

[0002] At present, with the continuous decline in the grade of alumina ore, high-carbon and other impurity-rich ores enter the alumina production system. High-carbon ore reacts with sodium aluminate solution to form carbonate. As carbonate in the system continues to accumulate, it has a great adverse impact on alumina production. The causticization of the side stream of the wash liquid has become a necessary process for the discharge of sodium carbonate.

[0003] In the washing liquid side stream causticizing system, the washing liquid is first pre-causticized, and after solid-liquid separation, the solid and washing liquid undergo a second causticizing high-temperature reaction. After the second causticizing high-temperature reaction, the mixed liquid needs to be settled and separated in a sedimentation tank into qualified sodium aluminate solution and causticizing slag, which are sent to different sections to meet the production liquid volume balance. Traditional sedimentation separation technology generally uses a large deep cone, flat bottom sedimentation tank and flocculant combined method to perform solid-liquid flocculation sedimentation separation.

[0004] The working temperature of traditional sedimentation scheme is usually below 100℃. In order to promote sedimentation, flocculants must be added to make tiny particles flocculate into large flocs to increase the sedimentation rate, so as to obtain reasonable sedimentation capacity and clear supernatant. Therefore, a large amount of flocculants are consumed, which increases production costs. At the same time, organic flocculants enter the production system, causing organic matter to pollute production materials. In addition, forced cooling will also cause energy loss and increase energy consumption. Therefore, under the condition of meeting production requirements at the same time, high-temperature sedimentation technology without flocculants is very meaningful. Utility Model Content

[0005] The utility model aims to provide a flocculant-free high-temperature sedimentation device to solve the problem that the traditional technology needs to consume a large amount of flocculants, which increases production costs and energy consumption.

[0006] The utility model solves the above technical problems with the following technical solutions: A flocculant-free high-temperature sedimentation device, comprising a sedimentation tank, wherein a central feed well is arranged inside the sedimentation tank; a plurality of nozzles are distributed on the edge of the central feed well, and each of the nozzles is connected to a feed pipe; a feed port extending from the side of the sedimentation tank is formed at the outer end of the feed pipe;

[0007] A stirring shaft is connected to the center of the sedimentation tank, and the stirring shaft extends to the lower part of the sedimentation tank through the central feed well; a rake is connected to the lower end of the stirring shaft; and a conical deflector is connected to the stirring shaft below the bottom opening position of the central feed well.

[0008] As a preferred solution for high-temperature sedimentation equipment without flocculants, the sedimentation tank includes a sedimentation cylinder, a closed top cover and a closed bottom cover; the closed top cover is formed on the top of the sedimentation cylinder, and the closed bottom cover is formed on the bottom of the sedimentation cylinder; the sedimentation cylinder is cylindrical, and the closed bottom cover is conical.

[0009] As a preferred solution for the flocculant-free high-temperature sedimentation equipment, a driving motor is connected to the top of the closed top cover, and a driving end of the driving motor is connected to the top of the stirring shaft.

[0010] As a preferred solution for the high-temperature sedimentation equipment without flocculants, the top end of the closed top cover is connected with a safety port, and the safety port is connected with a safety valve;

[0011] The upper end side of the sedimentation cylinder is connected with an overflow port, and the overflow port is connected with a discharge regulating valve.

[0012] As a preferred solution for the high-temperature sedimentation equipment without flocculants, the lower end of the closed bottom cover is connected with a discharge port, and the discharge port is connected with a discharge valve; one side of the closed bottom cover is provided with a circulation port, and the circulation port is connected with a circulation valve;

[0013] The discharge valve is connected to a variable frequency pump via a first conveying pipeline, and the variable frequency pump is connected to a discharge pipeline; the discharge pipeline is connected to the circulation valve via a second conveying pipeline; and a circulation control valve is provided on the second conveying pipeline.

[0014] As a preferred solution for the flocculant-free high-temperature sedimentation equipment, a central well support frame is connected between the side of the central feed well and the inner wall of the sedimentation tank.

[0015] As a preferred solution for the flocculant-free high-temperature sedimentation equipment, the diameter of the bottom opening of the central feed well is smaller than the maximum outer diameter of the conical guide.

[0016] As a preferred solution for the high-temperature sedimentation equipment without flocculants, the nozzles are provided with four nozzles, and the four nozzles are evenly distributed around the central feed well; the outside of each nozzle is connected to a feed pipe;

[0017] The diameter of the nozzle at one end close to the feed pipe is smaller than the diameter of the nozzle at one end close to the central feed well.

[0018] The beneficial effects of the utility model are as follows: it includes a sedimentation tank, a central feed well is arranged inside the sedimentation tank; a plurality of nozzles are distributed on the edge of the central feed well, each nozzle is connected to a feed pipe; a feed port extending from the side of the sedimentation tank is formed at the outer end of the feed pipe; a stirring shaft is connected to the center of the sedimentation tank, and the stirring shaft extends to the lower part of the sedimentation tank through the central feed well; a rake is connected to the lower end of the stirring shaft; and a conical flow guide is connected to the stirring shaft below the bottom opening of the central feed well. The utility model does not need to perform temperature reduction and pressure reduction operations, does not need to add flocculants and other sedimentation-promoting agents, can directly and quickly settle, reduce production costs, avoid organic flocculants entering the production system to cause organic matter to pollute production materials, and reduce energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the implementation or the prior art description. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0020] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment in size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0021] Figure 1 A schematic diagram showing the relationship between the sedimentation rate and temperature of the same solution concentration in the flocculant-free high-temperature sedimentation method provided by an embodiment of the utility model;

[0022] Figure 2 A schematic diagram of the structure of a flocculant-free high-temperature sedimentation device used in the flocculant-free high-temperature sedimentation method provided in an embodiment of the utility model;

[0023] Figure 3 A schematic diagram of the distribution of the feed pipe, the nozzle and the central feed well in the flocculant-free high-temperature sedimentation method provided by an embodiment of the utility model;

[0024] Figure 4 A schematic diagram of feeding in the flocculant-free high-temperature sedimentation method provided in an embodiment of the utility model.

[0025] In the figure, 1. sedimentation tank; 2. central feed well; 3. nozzle; 4. feed pipe; 5. feed port; 6. stirring shaft; 7. rake; 8. conical guide; 9. sedimentation cylinder; 10. closed top cover; 11. closed bottom cover; 12. drive motor; 13. safety port; 14. safety valve; 15. overflow port; 16. overflow regulating valve; 17. discharge port; 18. discharge valve; 19. circulation port; 20. circulation valve; 21. first conveying pipeline; 22. frequency conversion pump; 23. discharge pipeline; 24. second conveying pipeline; 25. circulation control valve; 26. central well support frame. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0028] The flocculant-free high-temperature sedimentation equipment provided in this embodiment makes use of the high temperature of the mixed liquid after the causticization reaction, and can directly carry out sedimentation and separation without cooling, thereby reducing the investment cost of cooling equipment and reducing energy consumption; at the same time, sedimentation is carried out at high temperature, because the viscosity and density of the solution decrease significantly with the increase of temperature, this property of the solution is very beneficial to increase the sedimentation rate, not only the sedimentation rate is faster, the volume of the sedimentation tank 1 can be reduced, the compression performance of the discharge from the bottom of the sedimentation tank 1 can be greatly improved, and the addition of sedimentation promoters such as flocculants can also be eliminated.

[0029] As we all know, the particle settling rate is mainly affected by the solid-liquid density difference, temperature, and viscosity. The Stokes still water particle free sedimentation formula is:

[0030] u=gd 2 (ρs-ρ) / 18μ①

[0031] Where u is the particle settling velocity (cm / s); ρs and ρ are the density of the particle and water, respectively (g / cm); g is the gravitational acceleration (cm / s 2 ), μ is the adhesion coefficient of water (Pa·s), and d is the particle diameter (cm).

[0032] By measuring the density of sodium aluminate solution, the calculation formula of the density of sodium aluminate solution is derived:

[0033] ρ 20℃ ={0 .5+(0.25+0.00144N+0.0009A+0.001865Nc)0.5}②

[0034] ρ x℃ ={0.5+(0.25+0.00144N+0.0009A+0.001865Nc)0.5}×(1.011-0.0005*x) ③

[0035] Where, N is the mass concentration of caustic soda (g / L); A is the mass concentration of alumina (g / L); Nc is the mass concentration of carbon alkali (g / L); ρ 20℃ is the density of sodium aluminate solution at 20°C.

[0036] Through experimental calculation and multivariate linear fitting, the relationship between the viscosity of sodium aluminate solution and temperature, alumina concentration, and solution rp was obtained:

[0037] Lnη=-1.554+1.139×1.645 / rp+0.0187×A-0.0503T④

[0038] Where rp is the mass ratio of alumina to caustic soda in the sodium aluminate solution; A is the mass concentration of alumina (g / L); η is the viscosity of the sodium aluminate solution (MPa·s); and T is the temperature of the sodium aluminate solution.

[0039] See also Figure 1 , is the relationship between the sedimentation rate and temperature at the same solution concentration (with 90°C as the reference point). Combining formulas ①, ③, and ④, the sedimentation rate of causticized slag in sodium aluminate solution is related to its own particle size, but in actual production, the particle size of the material is relatively stable, and the factor with the greatest impact is the solution temperature. The sedimentation rate at 150°C is 20 times that at 90°C, and the sedimentation rate at 200°C is 200 times that at 90°C. Therefore, the high-temperature sedimentation method without flocculant proposed in this embodiment is theoretically feasible. The following is the specific content of the embodiment of the utility model.

[0040] See also Figure 2 , Figure 3 and Figure 4In this embodiment, a flocculant-free high-temperature sedimentation equipment includes a sedimentation tank 1, and a central feed well 2 is arranged inside the sedimentation tank 1; a plurality of nozzles 3 are distributed on the edge of the central feed well 2, and each nozzle 3 is connected to a feed pipe 4; a feed port 5 extending from the side of the sedimentation tank 1 is formed at the outer end of the feed pipe 4; a stirring shaft 6 is connected to the center of the sedimentation tank 1, and the stirring shaft 6 extends to the lower part of the sedimentation tank 1 through the central feed well 2; a rake 7 is connected to the lower end of the stirring shaft 6; and a conical deflector 8 is connected to the stirring shaft 6 below the bottom opening position of the central feed well 2.

[0041] Based on the flocculant-free high-temperature sedimentation equipment of this embodiment, the mixed liquid formed by the sodium aluminate solution after the causticizing reaction and the causticizing slag is transported to the central feed well 2 inside the sedimentation tank 1 through the feed pipe 4; before the mixed liquid enters the central feed well 2, the energy of the mixed liquid is dispersed through the nozzle 3, so that the speed of the mixed liquid entering the central feed well 2 is reduced to no more than 1m / s, so as to reduce the disturbance of the sedimentation material inside the sedimentation tank 1 during the mixed liquid feeding process without adding flocculants.

[0042] In this embodiment, the sedimentation tank 1 includes a sedimentation cylinder 9, a closed top cover 10 and a closed bottom cover 11; the closed top cover 10 is formed at the top of the sedimentation cylinder 9, and the closed bottom cover 11 is formed at the bottom of the sedimentation cylinder 9; the sedimentation cylinder 9 is cylindrical, and the closed bottom cover 11 is conical. The top end of the closed top cover 10 is connected to a driving motor 12, and the driving end of the driving motor 12 is connected to the top of the stirring shaft 6. Thus, the material settled at the bottom of the sedimentation tank 1 can be stirred to change the rheological properties of the sedimentation material, and the liquid-solid ratio of the sedimentation material can be adjusted to prevent the bottom of the sedimentation tank 1 from being blocked.

[0043] In this embodiment, there are four nozzles 3, which are evenly distributed around the central feed well 2; a feed pipe 4 is connected to the outside of each nozzle 3; the caliber of the nozzle 3 near the feed pipe 4 is smaller than the caliber of the nozzle 3 near the central feed well 2. By adopting four evenly distributed decompression nozzles 3, each nozzle 3 is symmetrical along the axis of the feed center well and is provided with an energy dispersion function; when the high-temperature mixed liquid enters the central feed well 2, the speed of the slurry is reduced to no more than 1m / s, preferably less than 0.8m / s or 0.5m / s. Therefore, the speed and kinetic energy of the high-temperature mixed liquid are such that when it hits the settled solids already in the central feed well 2, it causes minimal interference to the settled solids in the sedimentation tank 1. The feeding method using the nozzle 3 can reduce the disturbance of the material inside the sedimentation tank 1 caused by the feed, and it is unnecessary to add flocculants and other sedimentation promoters.

[0044] In this embodiment, the temperature of the mixed solution formed by the sodium aluminate solution and the causticized slag after the causticizing reaction is controlled at 90-200°C. From the theoretical analysis and experiments above, it can be obtained that the sedimentation rate of the causticized slag in the sodium aluminate solution is related to the particle size itself, but in actual production, the particle size of the material is relatively stable, and the factor with the greatest influence is the solution temperature. The sedimentation rate at 150°C is 20 times that at 90°C, and the sedimentation rate at 200°C is 200 times that at 90°C. Therefore, it is better to control the temperature of the mixed solution at 90-200°C. With the help of the high temperature mixed solution itself, there is no need to perform cooling and pressure reduction operations, and no need to add flocculants or other sedimentation promoters, and it can be directly and quickly precipitated.

[0045] In this embodiment, the top of the closed top cover 10 is connected with a safety port 13, and the safety port 13 is connected with a safety valve 14; the safety port 13, the safety valve 14 and the pressure in the sedimentation tank 1 can realize the intrinsic safety of the equipment.

[0046] In this embodiment, the upper side of the settling cylinder 9 is connected with an overflow port 15, and the overflow port 15 is connected with an overflow regulating valve 16. The overflow regulating valve 16 automatically adjusts the outlet flow of the overflow port 15, which can effectively control the temperature and pressure in the settling tank 1 and more effectively ensure the settling speed.

[0047] In this embodiment, the lower end of the closed bottom cover 11 is connected with a discharge port 17, and the discharge port 17 is connected with a discharge valve 18; a circulation port 19 is provided on one side of the closed bottom cover 11, and the circulation port 19 is connected with a circulation valve 20; the discharge valve 18 is connected with a variable frequency pump 22 via a first conveying pipeline 21, and the variable frequency pump 22 is connected with a discharge pipeline 23; the discharge pipeline 23 is connected with the circulation valve 20 via a second conveying pipeline 24; and a circulation control valve 25 is provided on the second conveying pipeline 24.

[0048] Specifically, the material settled in the sedimentation tank 1 is stirred by the energy provided by the stirring shaft 6 to change the rheological properties of the bottom slurry, reduce the viscosity of the slurry, and improve the fluidity of the slurry to prevent blockage. The material output from the discharge port 17 is discharged through the first conveying pipeline 21 and the discharge pipeline 23. The second conveying pipeline 24 can be used to automatically adjust the liquid-solid ratio of the bottom discharge, and the possibility of blockage of the bottom discharge of the sedimentation tank 1 can be further prevented in combination with the circulation valve 20.

[0049] In this embodiment, a central well support frame 26 is connected between the side of the central feed well 2 and the inner wall of the sedimentation tank 1; the diameter of the bottom opening of the central feed well 2 is smaller than the maximum outer diameter of the conical deflector 8.

[0050] Specifically, the central well support frame 26 plays a role in fixing the central feed well 2, and a conical guide device 8 is set at the lower outlet of the central feed well 2, which can change the flow direction of the slurry discharged from the central feed well 2, avoid the slurry directly rushing to the already formed sedimentation layer, and prevent interference with sedimentation.

[0051] In a possible embodiment, the closed bottom cover 11 of the settling tank 1 has inclined sides, and these inclined sides form an angle between 30° and 45° with the horizontal plane. An angle of about 30° is preferred, which can provide a good solid flow from the settling cylinder 9.

[0052] In summary, the flocculant-free high-temperature sedimentation equipment adopted by the utility model comprises a sedimentation tank 1, wherein a central feed well 2 is arranged inside the sedimentation tank 1; a plurality of nozzles 3 are distributed on the edge of the central feed well 2, and each nozzle 3 is connected to a feed pipe 4; a feed port 5 extending from the side of the sedimentation tank 1 is formed at the outer end of the feed pipe 4; a stirring shaft 6 is connected to the center of the sedimentation tank 1, and the stirring shaft 6 extends to the lower part of the sedimentation tank 1 through the central feed well 2; a rake 7 is connected to the lower end of the stirring shaft 6; the stirring shaft 6 is at the bottom opening position of the central feed well 2. A conical flow guide 8 is connected below. The utility model method transports the mixed liquid formed by the sodium aluminate solution and the causticized slag after the causticization reaction to the central feed well 2 inside the sedimentation tank 1 through the feed pipe 4; before the mixed liquid enters the central feed well 2, the energy of the mixed liquid is dispersed through the nozzle 3, so that the speed of the mixed liquid entering the central feed well 2 is reduced to no more than 1m / s, so as to reduce the disturbance of the sedimentation materials inside the sedimentation tank 1 during the mixed liquid feeding process without adding flocculants. The utility model uses the temperature of the high-temperature mixed liquid itself, does not need to perform cooling and pressure reduction operations, does not need to add flocculants and other sedimentation promoters, can directly and quickly settle, reduce production costs, avoid organic flocculants entering the production system to cause organic matter to pollute production materials, and reduce energy consumption.

[0053] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A flocculant-free high-temperature sedimentation device, characterized in that: The invention comprises a sedimentation tank (1), wherein a central feed well (2) is provided inside the sedimentation tank (1); a plurality of nozzles (3) are distributed on the edge of the central feed well (2), and each of the nozzles (3) is connected to a feed pipe (4); and a feed port (5) extending from the side of the sedimentation tank (1) is formed at the outer end of the feed pipe (4); The center of the sedimentation tank (1) is connected to a stirring shaft (6), and the stirring shaft (6) extends to the lower part of the sedimentation tank (1) through the central feed well (2); the lower end of the stirring shaft (6) is connected to a rake (7); and the stirring shaft (6) is connected to a conical deflector (8) below the bottom opening of the central feed well (2).

2. The high temperature sedimentation equipment without flocculant according to claim 1, characterized in that: The sedimentation tank (1) comprises a sedimentation cylinder (9), a closed top cover (10) and a closed bottom cover (11); the closed top cover (10) is formed at the top of the sedimentation cylinder (9), and the closed bottom cover (11) is formed at the bottom of the sedimentation cylinder (9); the sedimentation cylinder (9) is cylindrical, and the closed bottom cover (11) is conical.

3. The high temperature sedimentation equipment without flocculant according to claim 2, characterized in that: The top end of the closed top cover (10) is connected to a drive motor (12), and the drive end of the drive motor (12) is connected to the top of the stirring shaft (6).

4. The high temperature sedimentation equipment without flocculant according to claim 2, characterized in that: The top end of the closed top cover (10) is connected to a safety port (13), and the safety port (13) is connected to a safety valve (14); The upper end side of the sedimentation cylinder (9) is connected to an overflow port (15), and the overflow port (15) is connected to a discharge regulating valve.

5. The high temperature sedimentation equipment without flocculant according to claim 2, characterized in that: The lower end of the closed bottom cover (11) is connected to a discharge port (17), and the discharge port (17) is connected to a discharge valve (18); a circulation port (19) is provided on one side of the closed bottom cover (11), and the circulation port (19) is connected to a circulation valve (20); The discharge valve (18) is connected to a variable frequency pump (22) via a first conveying pipeline (21), and the variable frequency pump (22) is connected to a discharge pipeline (23); the discharge pipeline (23) is connected to the circulation valve (20) via a second conveying pipeline (24); and a circulation control valve (25) is provided on the second conveying pipeline (24).

6. The high temperature sedimentation equipment without flocculant according to claim 1, characterized in that: A central well support frame (26) is connected between the side of the central feed well (2) and the inner wall of the sedimentation tank (1).

7. The high temperature sedimentation equipment without flocculant according to claim 1, characterized in that: The diameter of the bottom opening of the central feed well (2) is smaller than the maximum outer diameter of the conical flow guide (8).

8. The high temperature sedimentation equipment without flocculant according to claim 1, characterized in that: There are four nozzles (3), and the four nozzles (3) are evenly distributed around the central feed well (2); the outer side of each nozzle (3) is connected to a feed pipe (4); The diameter of the nozzle (3) at one end close to the feed pipe (4) is smaller than the diameter of the nozzle (3) at one end close to the central feed well (2).

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