A system and method for efficiently recovering phosphorus from sludge

Abstract

The application discloses a kind of high-efficiency recovery phosphorus system and recovery phosphorus method of mud phosphorus, belong to mud phosphorus processing technical field.The application solves the problem that equipment pipeline is easily corroded, blocked and the like when the grade of mud phosphorus is slightly higher when conveying and processing mud phosphorus.The application passes into vertical flow settling tank by mud phosphorus and hot water, so that mud phosphorus is stratified after being impacted by hot water and then is settled;Coarse phosphorus deposited at the bottom of vertical flow settling tank is conveyed to coarse phosphorus refining section to obtain finished product yellow phosphorus, overflow water, slurry and hot water in vertical flow settling tank are input into next stage vertical flow settling tank for multiple stratified settling until low-grade mud phosphorus is obtained;Low-grade mud phosphorus is conveyed to mud phosphorus processing section for processing to obtain yellow phosphorus product.The application separates phosphorus from mud phosphorus by multiple vertical flow settling tanks combined with hot water impact settling for high-grade mud phosphorus, reduces the phosphorus content of high-grade mud phosphorus, greatly improves the start-up rate of mud phosphorus processing device and the processing capacity of mud phosphorus.

Description

Technical Field

[0001] This invention belongs to the field of mud phosphorus treatment technology, specifically relating to a high-efficiency phosphorus recovery system and method for mud phosphorus. Background Technology

[0002] Phosphorus mud is one of the main byproducts generated during the production of yellow phosphorus and is classified as a hazardous solid waste in the phosphorus chemical industry. The treatment and utilization of phosphorus mud 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 industry, but more seriously, it causes serious environmental pollution problems. Therefore, almost all domestic yellow phosphorus manufacturers are exploring the treatment and utilization of phosphorus mud in order to achieve good environmental, economic and social benefits.

[0003] The current mainstream recycling technology is to separate mud phosphorus by heating. However, when the mud phosphorus grade is slightly high, the equipment and pipelines used for conveying and processing mud phosphorus suffer from serious problems such as corrosion and blockage, resulting in low processing capacity and low start-up rate of the equipment, as well as high energy consumption. Summary of the Invention

[0004] In response to the problems of corrosion and blockage in the equipment and pipelines for conveying and processing mud phosphorus when the mud phosphorus grade is slightly high, which are caused by heating and separating mud phosphorus, resulting in low equipment throughput and operating rate and high energy consumption, this invention provides a high-efficiency mud phosphorus recovery system and method.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for efficient phosphorus recovery from mud phosphorus includes the following steps:

[0007] S1: The mud and phosphorus and hot water are continuously fed into the vertical flow settling tank, so that the mud and phosphorus settle in layers after being impacted by hot water in the vertical flow settling tank.

[0008] S2: As hot water continues to flow in, the slurry that has undergone dephosphorization in the previous vertical flow settling tank overflows into the next vertical flow settling tank. At this time, slurry and phosphorus are continuously introduced into the previous vertical flow settling tank, and hot water is introduced into the next vertical flow settling tank, so that the slurry that has undergone dephosphorization is subjected to hot water impact and settles in layers again.

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

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

[0011] By adopting this technical solution, the present invention separates phosphorus from high-grade mud phosphorus through multi-stage vertical flow settling tanks combined with hot water impact settling, thereby reducing the phosphorus content of mud phosphorus. This effectively reduces the phosphorus content of mud phosphorus treated by the mud phosphorus recovery and treatment device, greatly improving the start-up rate and processing capacity of the mud phosphorus treatment device. Compared with direct heating to separate high-grade mud phosphorus, the recovery efficiency of yellow phosphorus in mud phosphorus is greatly improved.

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

[0013] After adopting this technical solution, the temperature of the overflow water obtained from the stratified settling in the vertical flow settling tank is 45-60℃. The overflow water from the final stage of the vertical flow settling tank is separated and used as hot water for impact in the vertical flow settling tank or as spray cooling water for the sludge-phosphorus treatment section, thereby reducing water consumption, saving production costs, and reducing phosphorus loss. The required temperature for spray cooling water is 45-60℃; therefore, the water in the overflow water collection tank meets the temperature requirements for spray water and can be used directly for spraying.

[0014] As a preferred option, the treatment steps of the mud-phosphorus treatment section are as follows:

[0015] S41: The obtained low-grade mud phosphorus is heated to obtain phosphorus vapor;

[0016] S42: Cooling water is used for spraying to condense phosphorus vapor, resulting in a mixture of crude phosphorus and water;

[0017] S43: Separate crude phosphorus from water;

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

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

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

[0021] Preferably, the temperature of the low-grade mud phosphorus after heating in S41 is higher than the boiling point of yellow phosphorus, and the temperature of the spray water in S42 is 45-60℃, with a gas-liquid ratio of 200-300:1.

[0022] Preferably, the temperature of the hot water used for impact is 55-70℃, the flow rate is 0.5-1.5m / s, and the residence time of the mud and phosphorus in each level of vertical flow settling tank 2 is not less than 0.5h.

[0023] This technical solution allows for the heating of mud phosphorus at this temperature, moltenning it and facilitating the breakdown of its colloidal structure. The mud phosphorus remains in each stage of the vertical flow settling tank for at least 0.5 hours to ensure effective phosphorus removal.

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

[0025] A high-efficiency phosphorus recovery system for mud phosphorus includes multiple vertical flow settling tanks connected in series. Each vertical flow settling tank is connected to a crude phosphorus refining section. A settling separation device is connected to the tail vertical flow settling tank. The settling separation device is connected to the mud phosphorus treatment section and an overflow water collection tank. The mud phosphorus treatment section is connected to the crude phosphorus refining section.

[0026] Preferably, the overflow water collection tank is connected to a spraying device via a pipeline equipped with a second pump body, and the overflow water collection tank is connected to various levels of vertical flow settling tanks via a pipeline equipped with a third pump body.

[0027] The mud-phosphorus treatment section includes a mud-phosphorus storage tank connected to a sedimentation and separation device. The mud-phosphorus storage tank is connected to a mud-phosphorus heating device via a pipeline equipped with a first pump body. The mud-phosphorus heating device is connected to a spraying device via a pipeline. The spraying device is connected to a spraying storage tank via a pipeline. The spraying storage tank is connected to a crude phosphorus refining section via a pipeline.

[0028] The spray storage tank is connected to the vertical flow settling tank and the spraying equipment respectively through pipelines equipped 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] This invention separates phosphorus from high-grade mud phosphorus by using a multi-stage vertical flow settling tank combined with hot water impact settling, thereby reducing the phosphorus content of the mud phosphorus. This effectively reduces the phosphorus content of the mud phosphorus recovery and treatment device, greatly improving the start-up rate and processing capacity of the mud phosphorus treatment device. Compared with direct heating to separate high-grade mud phosphorus, the recovery efficiency of yellow phosphorus in mud phosphorus is greatly improved. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the efficient phosphorus recovery system in mud phosphorus of the present invention;

[0032] Among them, 1-crude phosphorus refining section, 2-vertical flow settling 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 Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0034] In the description of the embodiments of this application, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] Example 1

[0036] like Figure 1 As shown, a high-efficiency phosphorus recovery system for mud phosphorus includes a series of multi-stage vertical flow settling tanks 2 connected in series. Each stage of the vertical flow settling tank 2 is connected to a crude phosphorus refining section 1. The vertical flow settling tank 2 at the tail end is connected to a settling separation device 3, which is connected to a mud phosphorus treatment section and an overflow water collection tank 5. The mud phosphorus treatment section is connected to the crude phosphorus refining section 1.

[0037] In this embodiment, the overflow water collection tank 5 is connected to the spraying equipment 10 through a pipeline equipped with a second pump body 7, and the overflow water collection tank 5 is connected to the vertical flow settling tanks 2 of each stage through a pipeline equipped with a third pump body 8.

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

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

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

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

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

[0043] A method for efficient phosphorus recovery from mud phosphorus includes the following steps:

[0044] S1: 35.2% grade mud phosphorus and hot water are introduced into the first-stage vertical flow settling tank 2, so that the mud phosphorus settles in layers after being impacted by hot water. The temperature of the hot water is 65℃ and the flow rate is 1.2m / s. The amount of mud phosphorus added is controlled according to the size of the vertical flow settling tank 2 to ensure that the average residence time of the mud phosphorus is not less than 0.5h. In this embodiment, the mud phosphorus is controlled to stay in the vertical flow settling tank 2 for 0.5h.

[0045] S2: As hot water continues to flow in, the slurry that has undergone dephosphorization in the previous vertical flow settling tank 2 overflows into the next vertical flow settling tank 2. At this time, slurry and phosphorus are continuously introduced into the previous vertical flow settling tank 2, and the above process is repeated. Hot water at a temperature of 65℃ and a flow rate of 1.2m / s is introduced into the next vertical flow settling tank 2, so that the slurry that has undergone dephosphorization is subjected to hot water impact and settles in layers again.

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

[0047] S4: The low-grade mud phosphorus with a grade of 9.6% is transported to the mud phosphorus treatment section for processing to obtain crude phosphorus. The crude phosphorus is then transported to the crude phosphorus refining section 1 to obtain the finished yellow phosphorus.

[0048] The processing steps for the mud-phosphorus treatment section are as follows:

[0049] S41: The low-grade mud phosphorus in the mud phosphorus storage tank 4 is transported to the mud phosphorus heating equipment 9, and the obtained low-grade mud phosphorus is heated by the mud phosphorus heating equipment 9 to obtain phosphorus vapor;

[0050] S42: Spraying is performed using the overflow water obtained from S3 or directly introduced external cooling water at a temperature of 45-60℃ to condense phosphorus vapor and obtain a mixture of crude phosphorus and water. The gas-liquid ratio of the spray 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 the finished yellow phosphorus. The separated water is at a temperature of 68℃. After the temperature drops to about 65℃, it is used as hot water for impact in the vertical flow settling tank, or after the temperature drops to about 45-60℃, the separated water is used as spray cooling water for S42.

[0053] Comparative Example 1

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

[0055] Comparative Example 2

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

[0057] Comparative Example 3

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

[0059] Comparative Example 4

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

[0061] Comparative Example 5

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

[0063] Comparative Example 6

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

[0065] Comparative Example 7

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

[0067] Comparative Example 8

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

[0069] Comparative Example 9

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

[0071] Comparative Example 10

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

[0073] Comparative Example 11

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

[0075] Table 1 shows the mud phosphorus grade before and after treatment in Example 1 and Comparative Examples 1-11 (to highlight the differences, the similarities between Comparative Examples 1-11 and Example 1 are not listed):

[0076] Table 1

[0077]

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

[0079] Table 2 shows the start-up rate and processing capacity of the mud-phosphorus treatment unit before and after adopting this process:

[0080] Table 2

[0081] Driving rate mud phosphorus treatment volume Yellow phosphorus recovery rate Before processing 70％ 0.5 tons / h 60％ After processing 90％ 0.9 tons / h 87％

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

[0083] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A method for efficient recovery of phosphorus from sludge phosphorus, characterized by: Includes the following steps: S1: The mud and phosphorus and hot water are continuously fed into the vertical flow settling tank (2) so that the mud and phosphorus are stratified and settled after being impacted by hot water in the vertical flow settling tank (2); S2: As hot water continues to flow in, the slurry that has undergone dephosphorization in the upper vertical flow settling tank (2) overflows into the lower vertical flow settling tank (2). At this time, slurry and phosphorus are continuously introduced into the upper vertical flow settling tank (2), and hot water is introduced into the lower vertical flow settling tank (2) so that the slurry that has undergone dephosphorization is subjected to hot water impact and settles in layers again. S3: The mud phosphorus is subjected to multiple stratified sedimentation through vertical flow settling tanks (2) until low-grade mud phosphorus is obtained. The crude phosphorus deposited at the bottom of each vertical flow settling tank (2) is periodically transported to the crude phosphorus refining section (1) to obtain the finished yellow phosphorus. S4: The obtained low-grade mud phosphorus is transported to the mud phosphorus treatment section for processing to obtain crude phosphorus. The obtained crude phosphorus is then transported to the crude phosphorus refining section (1) to obtain the finished yellow phosphorus. The processing steps for the mud-phosphorus treatment section are as follows: S41: The obtained low-grade mud phosphorus is heated to obtain phosphorus vapor; S42: Cooling water is used for spraying to condense phosphorus vapor, resulting in a mixture of crude phosphorus and water; S43: Separate crude phosphorus from water; S44: The crude phosphorus is transported to the crude phosphorus refining section (1) for refining to obtain the finished yellow phosphorus; The temperature of the hot water used for impact is 55-70℃, the flow rate is 0.5-1.5m / s, and the mud and phosphorus stay in the vertical flow settling tanks (2) at each level for no less than 0.5h; The phosphorus content of the untreated mud phosphorus was greater than or equal to 20%, while the phosphorus content of the resulting low-grade mud phosphorus was less than or equal to 10%. In S3, the overflow water obtained from the stratified sedimentation of the last stage vertical flow sedimentation tank (2) is transported to the sedimentation separation equipment (3) for sedimentation separation to obtain low-grade mud and phosphorus and water. The water is transported to the overflow water collection tank (5) for use as impact water in the vertical flow sedimentation tank (2) or as spray cooling water in the mud and phosphorus treatment section. In S41, the temperature of the low-grade mud phosphorus after heating is higher than the boiling point of yellow phosphorus. In S42, the temperature of the spray water is 45-60℃, and the gas-liquid ratio of the spray is 200-300:

1. S43 also includes using the separated water as hot water for impact in the vertical flow settling tank (2) or as spray cooling water in S42.

2. A high-efficiency recovery of phosphorus system for sludge phosphorus, characterized in that: The method for efficient phosphorus recovery from mud phosphorus as described in claim 1 includes a series of multi-stage vertical flow settling tanks (2), each stage of which is connected to a crude phosphorus refining section (1). The vertical flow settling tank (2) at the tail end is connected to a settling separation device (3), which is connected to a mud phosphorus treatment section and an overflow water collection tank (5). The mud phosphorus treatment section is connected to the crude phosphorus refining section (1).

3. The system for efficient recovery of phosphorus from sludge according to claim 2, characterized in that: The overflow water collection tank (5) is connected to the spraying equipment (10) through a pipeline equipped with a second pump body (7), and the overflow water collection tank (5) is connected to the vertical flow settling tanks (2) at all levels through a pipeline equipped with a third pump body (8). 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) via a pipeline equipped with a first pump body (6). The mud-phosphorus heating device (9) is connected to a spraying device (10) via a pipeline. The spraying device (10) is connected to a spraying storage tank (11) via a pipeline. The spraying storage tank (11) is connected to the crude phosphorus refining section (1) via a pipeline. The spray storage tank (11) is connected to the vertical flow settling tank (2) and the spray equipment (10) respectively through a pipeline equipped with a fourth pump body (12).

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