System and method for efficiently recovering phosphorus from phosphorus sludge

Abstract

The invention discloses an efficient phosphorus recovery system and method for phosphorus sludge, and belongs to the technical field of phosphorus sludge treatment. The invention solves the problem that the equipment pipeline for conveying and treating the phosphorus sludge is easy to corrode and block when the grade of the phosphorus sludge is slightly higher. Phosphorus sludge and hot water are introduced into a vertical flow settling tank, so that the phosphorus sludge is subjected to layered settling after being impacted by the hot water; conveying the crude phosphorus deposited at the bottom of the vertical-flow settling tank to a crude phosphorus refining section to obtain a finished product yellow phosphorus, and inputting overflow water, slurry and hot water in the vertical-flow settling tank to a next-stage vertical-flow settling tank to carry out layered settling for multiple times until low-grade phosphorus sludge is obtained; and the low-grade phosphorus sludge is conveyed to a phosphorus sludge treatment section to be treated, and a yellow phosphorus product is obtained. According to the invention, the high-grade phosphorus sludge is subjected to multi-stage vertical flow sedimentation in combination with hot water impact sedimentation to separate phosphorus from the phosphorus sludge, so that the phosphorus content of the high-grade phosphorus sludge is reduced, and the start-up rate of the phosphorus sludge treatment device and the treatment capacity of the phosphorus sludge are greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge phosphorus treatment, and in particular relates to a sludge phosphorus efficient phosphorus recovery system and a phosphorus recovery method. Background Art

[0002] It is one of the main by-products produced in the production process of yellow phosphorus and is a hazardous solid waste in the phosphorus chemical industry. The treatment and utilization of mud phosphorus is a very important issue in the production of yellow phosphorus. It not only affects the phosphorus recovery rate and production cost in the yellow phosphorus industrial production, but also causes serious environmental pollution. Therefore, almost all domestic yellow phosphorus manufacturers are exploring the treatment and utilization of mud phosphorus in order to achieve good environmental, economic and social benefits.

[0003] The mainstream existing recovery technology is to heat and separate the mud phosphorus. However, when the grade of the mud phosphorus is slightly higher, the equipment and pipelines for transporting and processing the mud phosphorus will be seriously corroded and blocked, resulting in low processing capacity and start-up rate of the device and high energy consumption. Summary of the invention

[0004] Aiming at the problems that mud phosphorus is heated and separated in the prior art, but when the grade of mud phosphorus is slightly higher, the equipment pipelines for transporting and processing mud phosphorus are seriously corroded and blocked, the processing capacity and start-up rate of the device are low, and the energy consumption is high, the present invention provides a mud phosphorus efficient phosphorus recovery system and phosphorus recovery method.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for efficiently recovering phosphorus from phosphorus sludge comprises the following steps:

[0007] S1: Continuously passing the sludge phosphorus and hot water into the vertical flow sedimentation tank, so that the sludge phosphorus is subjected to the impact of hot water in the vertical flow sedimentation tank and then settles in layers;

[0008] S2: With the continuous introduction of hot water, the dephosphorized sludge in the upper vertical flow settling tank flows into the lower vertical flow settling tank in an overflow manner. At this time, the sludge phosphorus continues to be introduced into the upper vertical flow settling tank, and hot water is introduced into the lower vertical flow settling tank, so that the dephosphorized sludge is impacted by hot water and then stratified and settled again;

[0009] S3: The mud phosphorus is subjected to multiple layered sedimentation through vertical flow sedimentation tanks at various levels until low-grade mud phosphorus is obtained. The crude phosphorus deposited at the bottom of each vertical flow sedimentation tank is regularly transported to the crude phosphorus refining section to obtain finished yellow phosphorus;

[0010] S4: The obtained low-grade mud phosphorus is transported to the mud phosphorus treatment section for treatment to obtain crude phosphorus, and the obtained crude phosphorus is transported to the crude phosphorus refining section to obtain finished yellow phosphorus.

[0011] After adopting the technical scheme, the present invention separates phosphorus from the mud phosphorus by performing multi-stage vertical flow sedimentation tank combined with hot water impact sedimentation on high-grade mud phosphorus, thereby reducing the phosphorus content of the mud phosphorus, thereby effectively reducing the phosphorus content of the mud phosphorus treated by the mud phosphorus recovery and treatment device, greatly improving the start-up rate of the mud phosphorus treatment device and the treatment amount of mud phosphorus, and compared with direct heating to separate high-grade mud phosphorus, the recovery efficiency of yellow phosphorus in the mud phosphorus is greatly improved.

[0012] Preferably, in S3, the overflow water obtained by stratified sedimentation in the last stage vertical flow sedimentation tank is transported to the sedimentation separation equipment for sedimentation separation to obtain low-grade mud phosphorus and water, and the water is transported to the overflow water collection tank for use as impact water for the vertical flow sedimentation tank or as spray cooling water for the mud phosphorus treatment section.

[0013] After adopting this technical solution, the temperature of the overflow water obtained by the vertical flow sedimentation tank is 45-60°C. The overflow water obtained by the vertical flow sedimentation tank of the last stage is separated and used as hot water for impact of the vertical flow sedimentation tank or as spray cooling water for the mud phosphorus treatment section to reduce water consumption, save production costs, and reduce phosphorus loss. The required temperature of the spray cooling water is 45-60°C, so the water in the overflow water collection tank meets the temperature of the spray water and can be directly used for spraying.

[0014] Preferably, the processing steps of the mud phosphorus treatment section are:

[0015] S41: heating the obtained low-grade phosphorus mud to obtain phosphorus steam;

[0016] S42: spraying with cooling water to condense the phosphorus vapor to obtain a mixture of crude phosphorus and water;

[0017] S43: separating crude phosphorus from water;

[0018] S44: The crude phosphorus is transported to the crude phosphorus refining section for refining to obtain finished yellow phosphorus.

[0019] Preferably, S43 also includes using the separated water as hot water for impact of the vertical flow sedimentation tank or using the separated water as spray cooling water in S42.

[0020] After adopting this technical solution, the temperature of the separated water is about 55-70°C, which can be used as hot water for impact or as spray water.

[0021] Preferably, the temperature of the low-grade phosphorus mud after heating in S41 is greater than the boiling point of yellow phosphorus, the temperature of the spraying water in S42 is 45-60°C, and the gas-liquid ratio of the spraying is 200-300:1.

[0022] Preferably, the temperature of the hot water used for impact is 55-70° C., the flow rate is 0.5-1.5 m / s, and the sludge phosphorus stays in each level of vertical flow sedimentation tank 2 for not less than 0.5 h.

[0023] After adopting this technical solution, the mud phosphorus can be heated at this temperature to make it melt, which is conducive to destroying the colloidal structure of the mud phosphorus. The mud phosphorus stays in the vertical flow sedimentation tanks at each level for no less than 0.5h to ensure the phosphorus removal effect.

[0024] Preferably, the phosphorus content of the mud phosphorus before treatment is greater than or equal to 20%, and the phosphorus content of the obtained low-grade mud phosphorus is less than or equal to 10%.

[0025] A system for efficiently recovering phosphorus from mud phosphorus comprises a plurality of vertical flow sedimentation tanks connected in series in sequence, wherein the vertical flow sedimentation tanks at each stage are connected to a crude phosphorus refining section, the vertical flow sedimentation tank at the tail is connected to a sedimentation separation device, the sedimentation separation device is connected to a mud phosphorus treatment section and an overflow water collection tank, and the mud phosphorus treatment section is connected to a crude phosphorus refining section.

[0026] Preferably, the overflow water collection tank is connected to a spraying device via a pipeline provided with a second pump body, and the overflow water collection tank is connected to each level of vertical flow sedimentation tank via a pipeline provided with a third pump body;

[0027] The mud phosphorus treatment section includes a mud phosphorus storage tank connected to the sedimentation separation equipment, the mud phosphorus storage tank is connected to the mud phosphorus heating equipment through a pipeline provided with a first pump body, the mud phosphorus heating equipment pipeline is connected to the spraying equipment, the spraying equipment pipeline is connected to the spray storage tank, and the spray storage tank is connected to the crude phosphorus refining section through a pipeline;

[0028] The spray storage tank is respectively connected to the vertical flow sedimentation tank and the spray equipment through a pipeline provided with a fourth pump body.

[0029] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0030] The present invention separates phosphorus from the mud phosphorus by subjecting high-grade mud phosphorus to multi-stage vertical flow sedimentation tanks combined with hot water impact sedimentation, thereby reducing the phosphorus content of the mud phosphorus, thereby effectively reducing the phosphorus content of the mud phosphorus treated by a mud phosphorus recovery and treatment device, greatly improving the start-up rate of the mud phosphorus treatment device and the treatment amount of the mud phosphorus, and compared with direct heating to separate high-grade mud phosphorus, the recovery efficiency of yellow phosphorus in the mud phosphorus is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the system for efficiently recovering phosphorus from sludge phosphorus in the present invention;

[0032] Among them, 1-crude phosphorus refining section, 2-vertical flow sedimentation tank, 3-sedimentation separation equipment, 4-mud phosphorus storage tank, 5-overflow water collection tank, 6-first pump body, 7-second pump body, 8-third pump body, 9-mud phosphorus heating equipment, 10-spraying equipment, 11-spraying storage tank, 12-fourth pump body. DETAILED DESCRIPTION

[0033] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0034] In the description of the embodiments of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or are the positions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0035] Example 1

[0036] like Figure 1 As shown, a sludge phosphorus efficient phosphorus recovery system comprises a multi-stage vertical flow sedimentation tank 2 connected in series, each stage of the vertical flow sedimentation tank 2 is connected to a crude phosphorus refining section 1, the vertical flow sedimentation tank 2 at the tail is connected to a sedimentation separation device 3, the sedimentation separation device 3 is connected to a sludge phosphorus treatment section and an overflow water collection tank 5, and the sludge phosphorus treatment section is connected to the crude phosphorus refining section 1.

[0037] In this embodiment, the overflow water collecting tank 5 is connected to the spraying device 10 through a pipeline provided with a second pump body 7, and the overflow water collecting tank 5 is connected to the vertical flow sedimentation tanks 2 at each level through a pipeline provided with a third pump body 8;

[0038] The mud phosphorus treatment section includes a mud phosphorus storage tank 4 connected to a sedimentation separation device 3, the mud phosphorus storage tank 4 is connected to a mud phosphorus heating device 9 through a pipeline provided with a first pump body 6, the mud phosphorus heating device 9 is pipeline-connected to a spray device 10, the spray device 10 is pipeline-connected to a spray storage tank 11, and the spray storage tank 11 is connected to the crude phosphorus refining section 1 through a pipeline;

[0039] The spray storage tank 11 is connected to the vertical flow sedimentation tank 2 and the spray equipment 10 respectively through a pipeline provided with a fourth pump body 12 .

[0040] In this embodiment, the spraying equipment 10 is a spray tower.

[0041] In this embodiment, three vertical flow sedimentation tanks 2 are provided, and the overflow pipe of the previous vertical flow sedimentation tank 2 is connected in series with the feed pipe of the next vertical flow sedimentation tank 2, so that the overflow water containing mud separated by sedimentation in the previous vertical flow sedimentation tank 2 is transported to the next vertical flow sedimentation tank 2 for further sedimentation, thereby performing three sedimentation and stratification of the mud phosphorus.

[0042] The specific structure of the crude phosphorus refining section 1 is the same as that in the prior art, so its specific structure will not be described in detail here.

[0043] A method for efficiently recovering phosphorus from phosphorus sludge comprises the following steps:

[0044] S1: Passing the sludge phosphorus with a grade of 35.2% and hot water into the first-stage vertical flow sedimentation tank 2, so that the sludge phosphorus is subjected to hot water shock and then stratified and settled. The temperature of the hot water is 65° C. and the flow rate is 1.2 m / s. The amount of sludge phosphorus added is controlled according to the size of the vertical flow sedimentation tank 2 to ensure that the average residence time of the sludge phosphorus is not less than 0.5 h. In this embodiment, the sludge phosphorus is controlled to stay in the vertical flow sedimentation tank 2 for 0.5 h;

[0045] S2: With the continuous introduction of hot water, the dephosphorized slurry in the upper vertical flow sedimentation tank 2 flows into the lower vertical flow sedimentation tank 2 in an overflow manner. At this time, the slurry phosphorus continues to be introduced into the upper vertical flow sedimentation tank 2. The above process is repeated, and hot water with a temperature of 65°C and a flow rate of 1.2 m / s is introduced into the lower vertical flow sedimentation tank 2, so that the dephosphorized slurry is subjected to hot water shock and then stratified and settled again;

[0046] S3: The sludge phosphorus is subjected to multiple stratified sedimentation through the vertical flow sedimentation tanks of various levels, and the overflow water obtained from the last stage of the vertical flow sedimentation tank is transported to the sedimentation separation device 3 for stratified sedimentation to obtain low-grade sludge phosphorus (9.6%) and water, and the water is transported to the overflow water collecting tank 5 for storage. The temperature of the obtained overflow water is about 48° C. The overflow water obtained from the overflow water collecting tank 5 is heated to about 65° C. through a pipeline provided with a third pump body 8 and then used as hot water for impact of the vertical flow sedimentation tank or directly used as spray cooling water for the sludge phosphorus treatment section; the crude phosphorus deposited at the bottom of each vertical flow sedimentation tank 2 is regularly transported to the crude phosphorus refining section (1) to obtain finished yellow phosphorus;

[0047] S4: transporting the obtained low-grade mud phosphorus with a grade of 9.6% to the mud phosphorus treatment section for treatment to obtain crude phosphorus, and transporting the obtained crude phosphorus to the crude phosphorus refining section 1 to obtain finished yellow phosphorus;

[0048] The processing steps of the mud phosphorus treatment section are:

[0049] S41: transporting the low-grade mud phosphorus in the mud phosphorus storage tank 4 to the mud phosphorus heating device 9, and heating the obtained low-grade mud phosphorus by the mud phosphorus heating device 9 to obtain phosphorus steam;

[0050] S42: using the overflow water obtained in S3 or directly introducing external cooling water with a temperature of 45-60°C for spraying to condense the phosphorus vapor to obtain a mixture of crude phosphorus and water, the spraying gas-liquid ratio is 260:1;

[0051] S43: crude phosphorus and water are separated by sedimentation in the spray storage tank 11 to obtain crude phosphorus and water;

[0052] S44: The crude phosphorus is transported to the crude phosphorus refining section 1 for refining to obtain finished yellow phosphorus. The separated water has a temperature of 68°C. After the temperature drops to about 65°C, it is used as hot water for impact in the vertical flow sedimentation tank, or after the temperature drops to about 45-60°C, the separated water is used as spray cooling water for S42.

[0053] Comparative Example 1

[0054] This embodiment is basically the same as the embodiment 1, except that the impact hot water temperature is 55°C.

[0055] Comparative Example 2

[0056] This embodiment is basically the same as the embodiment 1, except that the impact hot water temperature is 70°C.

[0057] Comparative Example 3

[0058] This embodiment is basically the same as the embodiment 1, except that the impact hot water flow rate is 0.5 m / s.

[0059] Comparative Example 4

[0060] This embodiment is basically the same as the embodiment 1, except that the impact hot water flow rate is 1.5 m / s.

[0061] Comparative Example 5

[0062] This embodiment is basically the same as the embodiment 1, except that the impact hot water temperature is 50°C.

[0063] Comparative Example 6

[0064] This embodiment is basically the same as the embodiment 1, except that the impact hot water temperature is 80°C.

[0065] Comparative Example 7

[0066] This embodiment is basically the same as the embodiment 1, except that the impact hot water temperature is 70° C. and the flow rate is 1.5 m / s.

[0067] Comparative Example 8

[0068] This embodiment is basically the same as the embodiment 1, except that the impact hot water temperature is 70° C. and the flow rate is 0.5 m / s.

[0069] Comparative Example 9

[0070] This embodiment is basically the same as the embodiment 1, except that the impact hot water temperature is 55° C. and the flow rate is 1.5 m / s.

[0071] Comparative Example 10

[0072] This embodiment is basically the same as the embodiment 1, except that the impact hot water temperature is 55° C. and the flow rate is 0.5 m / s.

[0073] Comparative Example 11

[0074] This embodiment is basically the same as the embodiment 1, except that hot water is introduced into the vertical flow sedimentation tank 2 only twice for impact.

[0075] The mud phosphorus grades of Example 1 and Comparative Examples 1-11 before and after treatment are shown in Table 1 (in order to highlight the differences, the similarities between Comparative Examples 1-11 and Example 1 are not filled in):

[0076] Table 1

[0077]

[0078] As can be seen from Table 1, by introducing hot water shock, the grade of high-grade mud phosphorus can be effectively reduced after multiple sedimentation of the mud phosphorus. A good separation effect can be achieved when the hot water shock temperature is 55-70°C. When the hot water temperature is too high, the separation effect is not significantly improved, and it will affect the spraying effect of the spray water in the later stage. The separation effect is better when the hot water flow rate is 0.5-1.5m / s.

[0079] The start-up rate and the treatment amount of mud phosphorus before and after the use of this process are shown in Table 2:

[0080] Table 2

[0081] Driving rate Mud phosphorus treatment capacity Yellow phosphorus recovery rate Before treatment 70％ 0.5t / h 60％ After treatment 90％ 0.9 tons / h 87％

[0082] It can be seen from Table 2 that reducing the phosphorus content of high-grade mud phosphorus greatly improves the start-up rate of the mud phosphorus treatment device, the mud phosphorus treatment capacity and the recovery rate of yellow phosphorus.

[0083] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A method for efficiently recovering phosphorus from phosphorus sludge, characterized in that: The following steps are involved: S1: continuously passing the sludge phosphorus and hot water into the vertical flow sedimentation tank (2), so that the sludge phosphorus is subjected to the impact of the hot water in the vertical flow sedimentation tank (2) and then settles in layers; S2: As hot water is continuously introduced, the sludge that has undergone phosphorus removal in the upper vertical flow sedimentation tank (2) flows into the lower vertical flow sedimentation tank (2) in an overflow manner. At this time, the sludge phosphorus continues to be introduced into the upper vertical flow sedimentation tank (2), and hot water is introduced into the lower vertical flow sedimentation tank (2), so that the sludge that has undergone phosphorus removal is impacted by hot water and then sedimented in layers again; S3: The phosphorus mud is subjected to multiple layered sedimentation in vertical flow sedimentation tanks (2) at various levels until low-grade phosphorus mud is obtained, and the crude phosphorus deposited at the bottom of each vertical flow sedimentation tank (2) is regularly transported to the crude phosphorus refining section (1) to obtain finished yellow phosphorus; S4: The obtained low-grade mud phosphorus is transported to the mud phosphorus treatment section for treatment to obtain crude phosphorus, and the obtained crude phosphorus is transported to the crude phosphorus refining section (1) to obtain finished yellow phosphorus.

2. The method for efficiently recovering phosphorus from phosphorus sludge according to claim 1, characterized in that: In S3, the overflow water obtained by layered sedimentation in the last stage of the vertical flow sedimentation tank (2) is transported to the sedimentation separation equipment (3) for sedimentation separation to obtain low-grade mud phosphorus and water, and the water is transported to the overflow water collection tank (5) to be used as impact water for the vertical flow sedimentation tank (2) or as spray cooling water for the mud phosphorus treatment section.

3. A method for efficiently recovering phosphorus from phosphorus sludge according to claim 1, characterized in that: The processing steps of the mud phosphorus treatment section are: S41: heating the obtained low-grade phosphorus mud to obtain phosphorus steam; S42: spraying with cooling water to condense the phosphorus vapor to obtain a mixture of crude phosphorus and water; S43: separating crude phosphorus from water; S44: The crude phosphorus is transported to the crude phosphorus refining section (1) for refining to obtain finished yellow phosphorus.

4. A method for efficiently recovering phosphorus from phosphorus sludge according to claim 3, characterized in that: S43 also includes using the separated water as hot water for impact in the vertical flow sedimentation tank (2) or using the separated water as spray cooling water in S42.

5. A method for efficiently recovering phosphorus from phosphorus sludge according to claim 3, characterized in that: The temperature of the low-grade phosphorus mud after heating in S41 is greater than the boiling point of yellow phosphorus, the temperature of the spray water in S42 is 45-60°C, and the gas-liquid ratio of the spray is 200-300:

1.

6. A method for efficiently recovering phosphorus from phosphorus sludge according to any one of claims 1 to 5, characterized in that: The temperature of the hot water used for impact is 55-70°C, the flow rate is 0.5-1.5 m / s, and the sludge phosphorus stays in each level of vertical flow sedimentation tank (2) for not less than 0.5 h.

7. A method for efficiently recovering phosphorus from phosphorus sludge according to any one of claims 1 to 5, characterized in that: The phosphorus content of the mud phosphorus before treatment is greater than or equal to 20%, and the phosphorus content of the obtained low-grade mud phosphorus is less than or equal to 10%.

8. A system for efficiently recovering phosphorus from sludge phosphorus, characterized in that: The invention comprises a plurality of vertical flow sedimentation tanks (2) connected in series, each of the vertical flow sedimentation tanks (2) being connected to a crude phosphorus refining section (1), the vertical flow sedimentation tank (2) at the tail being connected to a sedimentation separation device (3), the sedimentation separation device (3) being connected to a sludge phosphorus treatment section and an overflow water collection tank (5), and the sludge phosphorus treatment section being connected to a crude phosphorus refining section (1).

9. A system for efficiently recovering phosphorus from sludge phosphorus according to claim 8, characterized in that: The overflow water collection tank (5) is connected to a spray device (10) via a pipeline provided with a second pump body (7), and the overflow water collection tank (5) is connected to each level of vertical flow sedimentation tanks (2) via a pipeline provided with a third pump body (8); The sludge phosphorus treatment section comprises a sludge phosphorus storage tank (4) connected to the sedimentation separation device (3); the sludge phosphorus storage tank (4) is connected to a sludge phosphorus heating device (9) via a pipeline provided with a first pump body (6); the sludge phosphorus heating device (9) is connected to a spray device (10) via a pipeline; the spray device (10) is connected to a spray storage tank (11) via a pipeline; and the spray storage tank (11) is connected to the crude phosphorus refining section (1) via a pipeline; The spray storage tank (11) is respectively connected to the vertical flow sedimentation tank (2) and the spray equipment (10) via a pipeline provided with a fourth pump body (12).

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