Pretreatment system and method for high-salt ammonia-containing wastewater

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a pretreatment system and method for high-salt ammonia-containing wastewater. The system comprises a sulfuric acid mother liquor storage tank, a first-stage neutralization tank, a first-stage filter tank, a second-stage neutralization tank and a horizontal spiral centrifuge which are sequentially connected, a solid-phase discharge port of the horizontal spiral centrifuge is connected with the first-stage neutralization tank through a pulping mechanism, and spray cleaning devices are mounted at a rotary drum and a solid-phase discharge end of the horizontal spiral centrifuge. According to the invention, a two-stage neutralization process is adopted, so that the PH value of calcium sulfate is reduced; and a spiral centrifugal separation method is adopted, so that the process requirements are met, the working site environment is improved, the automation level of process equipment is improved, and the labor is reduced and the efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular relates to a pretreatment system and method for high-salt ammonia-containing wastewater. Background Art

[0002] In the process of treating high-salt and high-ammonia nitrogen wastewater, due to the high ammonia content in this type of wastewater, in order to facilitate deammoniation, it is often necessary to add calcium oxide to the wastewater to increase the pH value of the wastewater to about 11.3, and then filter it. The clear liquid after filtration is sent to the next stage for stripping and deammoniation, and the resulting ammonia water is recycled.

[0003] In this treatment method, after the pH value of the wastewater is adjusted to about 11.3, the pH value of the waste residue after filtration is too high, which is a highly alkaline hazardous substance, and is accompanied by a large amount of ammonia volatilization, which is difficult to handle. The commonly used filtering equipment for this treatment method is the plate and frame filter press. Although the plate and frame filter press has the advantages of simple structure, durable parts, easy operation and maintenance, it also has the following problems:

[0004] 1. Plate and frame filter presses are generally operated intermittently, require special personnel to supervise, and have a low degree of automation.

[0005] 2. Due to the high salt content in the slurry, during the filtration process, salt precipitates and scales on the filter cloth, causing the filter mesh holes on the filter cloth to be blocked, resulting in a decrease in filtration efficiency. The filter cloth needs to be frequently replaced or cleaned, which increases labor costs and operating costs. The replaced filter cloth has adhered materials and scale, and can only be treated as solid waste, increasing treatment costs and high operating costs.

[0006] Plate and frame filter (or belt filter) is semi-open production. The material is exposed to the outside during unloading. Under high alkalinity conditions (PH value 11.5), ammonia in the material is easily released into the air, polluting the environment, causing corrosion of on-site equipment, and seriously endangering the health of the operator.

[0007] Therefore, there is an urgent need for a pretreatment system and method for high-salt ammonia-containing wastewater to solve the above problems. Summary of the invention

[0008] In order to overcome the above defects in the prior art, the present invention provides a pretreatment system and method for high-salt ammonia wastewater. The present invention adopts a two-stage neutralization process to reduce the pH value of calcium sulfate and reduce the clogging of the centrifuge.

[0009] To achieve one of the above purposes, the present invention adopts the following technical solution:

[0010] A pretreatment system for high-salt ammonia-containing wastewater, the system comprises a sulfate mother liquor storage tank, a primary neutralization tank, a primary filtering tank, a secondary neutralization tank and a horizontal spiral centrifuge which are connected in sequence, the solid phase discharge port of the horizontal spiral centrifuge is connected to the primary neutralization tank through a pulping mechanism, and the drum and the solid phase discharge end of the horizontal spiral centrifuge are both equipped with spray cleaning devices.

[0011] Preferably, the liquid phase outlet of the horizontal spiral centrifuge is connected to the sedimentation tank through a clear liquid valve, the sedimentation outlet of the sedimentation tank is connected to the inlet of a raw pulp tank containing a flocculant through a sedimentation tank pump, and the outlet of the raw pulp tank is connected to the horizontal spiral centrifuge; the liquid phase outlet of the horizontal spiral centrifuge is also connected to a primary neutralization tank through a mixed liquid valve.

[0012] Preferably, the pulping mechanism includes a pulping tank A, a pulping tank B and a slurry storage tank connected in sequence, the feed port of the pulping tank A is connected to the solid phase discharge port of the horizontal spiral centrifuge, the discharge port of the pulping tank A is connected to the feed port of the pulping tank B, the discharge port of the pulping tank B is connected to the feed port of the slurry storage tank, and the discharge port of the slurry storage tank is connected to the primary neutralization tank.

[0013] Preferably, the liquid inlet end of the spray cleaning device is connected to the sulfate mother liquor storage tank, the nitric acid storage tank and the tap water pipe respectively, and the liquid outlet end of the spray cleaning device is arranged at the drum of the horizontal spiral centrifuge and above the solid phase discharge end.

[0014] Preferably, the feed port of pulping tank A is connected to the pulping rehydration tank via a pulping rehydration pump.

[0015] Preferably, a flow meter is installed at the outlet of the pulping and replenishing pump; a radar level meter is installed on the pulping tank B, and both the flow meter and the radar level meter are connected to the PLC control box.

[0016] Preferably, the horizontal spiral centrifuge, the sedimentation tank, the raw pulp tank and the beating mechanism are all connected to the ammonia spray absorption tower through a negative pressure absorption pipe.

[0017] To achieve the second purpose above, the present invention provides a method for pretreating high-salt ammonia-containing wastewater, and the specific steps are as follows:

[0018] S1, take a pool of sulfate mother liquor to be treated and pass it into the secondary neutralization tank, and add calcium oxide into the secondary neutralization tank until the pH value of the wastewater is 11.3, the neutralized wastewater is passed into a horizontal spiral centrifuge for centrifugation, and the solid phase after centrifugation is passed into a pulping mechanism and then into a primary neutralization tank;

[0019] S2. The remaining sulfate mother liquor to be treated is passed into a primary neutralization tank, and then flows through a primary filtration tank, a secondary neutralization tank, and a horizontal spiral centrifuge in sequence. The solid phase after centrifugation in the horizontal spiral centrifuge is passed into a pulping mechanism and then transported to the primary neutralization tank. The liquid phase after centrifugation is passed into a sedimentation tank. The clear liquid on the top of the sedimentation tank overflows to the next stripping section. The solid phase precipitated in the sedimentation tank is passed into a raw pulp tank for flocculation and then passed into a horizontal spiral centrifuge.

[0020] Preferably, in step S1, in the first 3 minutes, the mixed liquid valve at the liquid phase outlet of the horizontal spiral centrifuge is opened, the clear liquid valve is closed, and the liquid phase after centrifugation is passed into a primary neutralization tank; after 3 minutes, the clear liquid valve at the liquid phase outlet of the horizontal spiral centrifuge is opened, the mixed liquid valve is closed, and the liquid phase after centrifugation is passed into a sedimentation tank, the clear liquid at the top of the sedimentation tank overflows to the next stripping section, and the solid phase precipitated in the sedimentation tank is passed into a raw pulp tank for flocculation and then into the horizontal spiral centrifuge; in step S2, the clear liquid valve at the liquid phase outlet of the horizontal spiral centrifuge is opened, and the mixed liquid valve is closed.

[0021] Preferably, the spray cleaning device is turned on before step S1.

[0022] The advantages of the present invention are:

[0023] (1) The present invention adopts a two-stage neutralization process to reduce the pH value of calcium sulfate; and adopts a spiral centrifugal separation method to meet the process requirements, improve the work site environment, improve the automation level of process equipment, and reduce manpower and increase efficiency.

[0024] (2) A two-stage neutralization method is adopted. After the sulfate mother liquor and the high-pH sulfate slag produced by the secondary neutralization are slurried, the sulfate mother liquor is subjected to primary neutralization again, thereby reducing the pH value of the calcium sulfate slag and increasing the pH value of the mother liquor. The mother liquor then enters the secondary neutralization tank, and calcium oxide is added to raise the pH value to about 11.3 as required by the process. Since the pH value of the acidic mother liquor in the primary neutralization tank has been raised to about 7.5, the amount of calcium oxide used in the secondary neutralization is reduced, the cost is reduced, and the water-soluble calcium oxide in the secondary neutralization tank is also fully utilized. In addition, the calcium sulfate slag produced by the primary neutralization is neutral (pH value is about 7) and can be reused as a raw material for other chemical products. The secondary neutralization filtration of the present invention adopts a horizontal screw centrifugal separation method instead of a plate and frame filter press. The equipment operates continuously, is automatically operated, the processing capacity is adjustable and controllable, the process indicators are stable, and the equipment operation is stable and reliable.

[0025] (3) The present invention solves the difficult problems of process index control and scaling by improving the process and equipment, adopting two-stage neutralization, selecting a horizontal spiral centrifuge, adding a sedimentation device and a unique multiple automatic cleaning design, and automatically detecting and adjusting the feed amount, thereby meeting the process requirements, ensuring continuous and stable operation of the equipment, and achieving unmanned automatic operation.

[0026] (4) The pulping in the present invention can make the alkaline semi-solid material separated by the centrifuge react with the sulfate mother liquor used for cleaning in advance, that is, a small portion of the sulfate mother liquor that needs to enter the primary neutralization tank is separated to clean the centrifuge discharge end and then react with the alkaline semi-solid material separated by the centrifuge, which not only neutralizes a portion of the sulfate mother liquor in advance, reducing the amount of mother liquor to be treated in one neutralization, but also cleans the centrifuge; the use of a pulping mechanism is convenient for metering, transportation and storage, and the closed transportation of solid slag avoids ammonia exposure and overflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a pulping process diagram of the horizontal spiral centrifuge of the present invention, wherein the solid line is the direction of the liquid phase or slurry, and the dotted line is the direction of the gas phase pipe.

[0028] Figure 2 It is a schematic diagram of the process of the present invention, wherein the solid line is the solid phase slurry pipeline and the dotted line is the mother liquor pipeline.

[0029] The meanings of the symbols in the figure are as follows:

[0030] 1. Horizontal spiral centrifuge; 11. Clear liquid valve; 12. Mixed liquid valve; 2. Sedimentation tank; 21. Sedimentation tank pump; 3. Raw pulp tank; 41. Pulping tank A; 42. Pulping tank B; 43. Radar level gauge; 5. Slurry storage tank; 6. Pulping replenishment tank; 61. Pulping replenishment pump; 7. Nitric acid storage tank; 8. Sulfuric acid mother liquor storage tank; 9. Absorption tower; 10. Tap water pipe. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0032] like Figure 1-2 As shown, a pretreatment system for high-salt ammonia wastewater is as follows:

[0033] 1. Based on the structure of the horizontal spiral centrifuge 1 and the characteristics of the materials, there are still escaped solid materials in the liquid phase of the effluent of the horizontal spiral centrifuge 1, and the solid content of the liquid phase of the effluent is high, which cannot meet the process requirements. Therefore, this system adds a sedimentation and backfiltration process, that is, a sedimentation tank 2 is added to the liquid phase effluent end of the horizontal spiral centrifuge 1, so that the effluent is first precipitated in the sedimentation tank 2, and the upper clear liquid overflows to the next stripping section. After precipitation, the solid content of the effluent meets the process requirements. The precipitated material at the bottom of the sedimentation tank of the sedimentation tank 2 is regularly transported to the raw pulp tank 3 by the sedimentation tank pump 21 (using PLC control to start regularly), and after adding flocculant to the raw pulp tank 3, it is transported to the horizontal spiral centrifuge 1 through the delivery pump for centrifugal dehydration again, which makes up for the disadvantage that the liquid phase of the horizontal spiral centrifuge 1 is not clear.

[0034] 2. The liquid phase outlet of the horizontal spiral centrifuge 1 is provided with a clear liquid valve 11 and a mixed liquid valve 12, which are automatically switched by PLC. When the horizontal spiral centrifuge 1 is started, the outlet water contains a large amount of waste residues. The clear liquid valve 11 leading to the sedimentation tank 2 is closed, and the mixed liquid valve 12 is opened. The unclarified mother liquid outlet water flows to the primary neutralization tank through the waste liquid valve; after the equipment runs stably (set after 180s), the clear liquid valve 11 is automatically opened, the mixed liquid valve 12 is closed, and the clear liquid enters the sedimentation tank 2, reducing the waste liquid containing residues entering the sedimentation tank 2.

[0035] 3. Two pulping tanks are installed at the lower part of the solid phase discharge of the horizontal spiral centrifuge 1, namely pulping tank A 41 and pulping tank B 42, which are used for continuous pulping and conveying. The material moves in a gravity flow from high to low position, saving energy. The pulping and rehydration pump 61 replenishes the neutral mother liquor in the pulping and rehydration tank into the pulping tank A 41. The material coming out of the horizontal spiral centrifuge 1 is stirred into slurry in the pulping tank A 41. The material that is not completely dispersed continues to be stirred in the middle and lower parts due to gravity. The molten slurry overflows from the upper part into the pulping tank B 42, and is stirred and pulped again to ensure that the slurry is melted. A flow meter is installed at the outlet of the pulping and rehydration pump 61. The pulping concentration is adjusted according to the flow meter and the start and stop setting time of the pulping and rehydration pump 61. An appropriate amount of mother liquor is added to obtain a suitable slurry solid content. A radar level gauge 43 is installed on the pulping tank B 42, and both are connected to the PLC control box. The liquid level is set by the radar level gauge 43 to control the start and stop of the delivery pump 44. That is, the pulping pump automatically starts when the set liquid level is reached, and stops when the liquid level is lower than the liquid level, thereby ensuring that the liquid level of the pulping tank B 42 remains within the set range, achieving the effect of automatic pulping by two pulping tanks.

[0036] 4. Because the treated wastewater has high salt content, high alkalinity and easy adhesion, the centrifuge is prone to scaling and clogging, which in turn causes the horizontal spiral centrifuge 1 to vibrate more, increase the resistance during rotation, discharge jams, equipment damage, etc. The scaling and clogging mainly occur in three locations: inside the drum, outside the drum and at the discharge port.

[0037] Specifically, the scaling problem inside the centrifuge was solved by three methods: sulfuric acid cleaning, nitric acid cleaning, and tap water cleaning. The first step was to use sulfuric acid mother liquor for cleaning, which can wash away the softer scaling materials on the surface and serve as a pre-cleaning for the next step of nitric acid cleaning. Since sulfuric acid mother liquor is waste acid that needs to be treated in the later stage, the amount of nitric acid used is reduced; the second step is to use nitric acid to clean the harder scaling layer. Calcium sulfate reacts with nitric acid and dissolves in nitric acid, thereby achieving the purpose of thoroughly cleaning the calcium scale; the third step is to use tap water to clean the residual nitric acid on the equipment to ensure the safety of personnel during equipment operation and maintenance.

[0038] During operation, the solid phase material discharge end of the centrifuge is sticky and easy to accumulate and clog. To address the clogging problem in this area, this system is equipped with a special spray cleaning device, which uses PLC automatic control to spray this area with mother liquor of sulfate at regular intervals and in fixed quantities to keep the lining and materials moist, and to prevent the materials from sticking to the discharge lining and accumulating at the discharge port to cause clogging. In addition, mother liquor of sulfate is a by-product waste acid of the workshop, and the subsequent process needs to be neutralized with slurry. Spraying with mother liquor of sulfate will not increase the use of additional water, which not only saves costs, but also solves the clogging problem.

[0039] Operation mode and pipeline route: Under normal operation of the equipment, the discharge cleaning valve and the outlet valve of the sulfate mother liquor pump are opened, the sulfate mother liquor pump is started, and the sulfate mother liquor is transported to the spray cleaning device to spray the discharge end of the horizontal spiral centrifuge 1. The material accumulated at the discharge end is washed with the mother liquor and directly enters the pulping tank A 41 through the gate valve. The spray cleaning device uses PLC to open and close regularly to control the spray water volume to avoid excessive mother liquor reacting with calcium slag to generate a large amount of gas and foam. At this time, the mixed liquid valve 12 and the solid phase bypass valve are closed.

[0040] After the centrifuge has been running for a long time, the equipment will be scaled inside and the discharge will be blocked, which will cause the motor load to increase and the torque to increase. After the external scaling, the motor will vibrate greatly when rotating at high speed. Therefore, the torque, vibration value and equipment interlocking function are set in the PLC electric control box of the equipment. When the equipment detects that the torque is too high and the vibration is too large, the equipment will automatically slow down and stop feeding, and enter the cleaning mode (sulfuric acid mother liquor, nitric acid, tap water cleaning in turn). After the cleaning is completed, it will enter the feeding operation mode again.

[0041] Operation mode and pipeline route: When the sulfate mother liquor is cleaned, the sulfate mother liquor pump is started, the sulfate mother liquor pump outlet valve, discharge cleaning valve, external drum cleaning valve, and feed cleaning valve are opened, the mixed liquor valve 12, the solid phase bypass valve, and the waste liquid valve are opened, and the cleaned mother liquor flows to the primary neutralization tank.

[0042] When nitric acid is used for cleaning, the nitric acid pump is started, the nitric acid pump outlet valve, discharge cleaning valve, external drum cleaning valve and feed cleaning valve are opened, the solid phase bypass valve of the discharge water pipe, the mixed liquid valve 12 and the nitric acid recovery valve are opened, and the nitric acid after cleaning returns to the nitric acid tank for cyclic cleaning.

[0043] 5. To ensure the pressure of the spray head during cleaning, the spray control valves at the three parts of the drum, namely, the feed cleaning valve, the outer drum cleaning valve, and the discharge cleaning valve, are opened and closed in sequence according to the time set by the PLC, that is, only one of the three valves is opened. When setting the time, the cleaning setting time inside the drum is relatively long (feed cleaning valve), and the cleaning time outside is relatively short (outer drum cleaning valve).

[0044] If it involves opening the cover for inspection or cleaning, use tap water in manual control mode in advance for cleaning. The cleaning pipeline route is the same as sulfuric acid cleaning and is omitted.

[0045] 6. Due to the property of releasing ammonia gas from the material, negative pressure absorption pipes are installed in the horizontal spiral centrifuge 1, sedimentation tank 2, raw pulp tank 3, pulping tank B 42, and slurry storage tank 5 to draw the released ammonia gas into the absorption tower 9 for absorption and utilization. The absorption tower 9 uses sulfuric acid mother liquor wastewater for absorption to maintain a slight negative pressure inside the equipment and containers, and the production site environment is pollution-free.

[0046] 7. Since the wastewater from the workshop is processed, the acidity of each batch is different, so the concentration of the material, that is, the solid content of the original slurry, fluctuates greatly, resulting in uneven solid phase discharge. That is, at the same feed rate, due to the increase in solid content, the discharge volume increases, resulting in an increase in the pusher load inside the centrifuge, causing problems such as the pusher device being stuck. In order to maintain the stable operation of the equipment, automatic adjustment control measures are taken for the feed amount of the centrifuge. According to the pusher torque of the centrifuge collected by the equipment, the frequency of the feed pump is automatically adjusted to control the feed amount to maintain a stable solid feed amount. The equipment torque is within the set range, ensuring the stable operation of the centrifuge.

[0047] A method for pretreating high-salt ammonia-containing wastewater, the specific steps are as follows:

[0048] S1, take a pool of to-be-treated sulfate mother liquor and pass it into the secondary neutralization tank, and add calcium oxide into the secondary neutralization tank until the pH value of the waste water is 11.3, the neutralized waste water is passed into the horizontal spiral centrifuge 1 for centrifugation, and the solid phase after centrifugation is passed into the beating mechanism and then into the primary neutralization tank; in the first 3 minutes after the operation of the horizontal spiral centrifuge 1, due to the large amount of waste residue contained in the effluent, the mixed liquor valve 12 of the liquid phase outlet end of the horizontal spiral centrifuge 1 is opened, the clear liquor valve 11 is closed, and the liquid phase after centrifugation is passed into the primary neutralization tank, 3 minutes later, the clear liquor valve 11 of the liquid phase outlet end of the horizontal spiral centrifuge 1 is opened, the mixed liquor valve 12 is closed, and the liquid phase after centrifugation is passed into the sedimentation tank 2, and the clear liquid on the top of the sedimentation tank 2 overflows to the next stripping section, and the solid phase precipitated in the sedimentation tank 2 is passed into the original pulp tank 3 for flocculation and then passed into the horizontal spiral centrifuge 1;

[0049] S2, the remaining sulfate mother liquor to be treated is passed into a primary neutralization tank, and then flows through a primary filtration tank, a secondary neutralization tank, and a horizontal spiral centrifuge 1 in sequence. The solid phase after centrifugation in the horizontal spiral centrifuge 1 is passed into a pulping mechanism and then transported to the primary neutralization tank. The liquid phase after centrifugation is passed into a sedimentation tank 2. The clear liquid on the top of the sedimentation tank 2 overflows to the next stripping section. The solid phase precipitated in the sedimentation tank 2 is passed into a raw pulp tank 3 for flocculation and then passed into the horizontal spiral centrifuge 1; the clear liquid valve 11 at the liquid phase outlet end of the horizontal spiral centrifuge 1 is opened, and the mixed liquid valve 12 is closed.

[0050] The whole process of the pretreatment method is that the mother liquor of sulfate first enters the secondary neutralization tank, and a certain amount of calcium oxide fine powder adjusts the pH value of the mother liquor to 11.3. At this time, the sewage includes waste liquid and solids (unreacted calcium oxide, calcium hydroxide (powdered calcium oxide dissolved in water) and calcium sulfate), and enters the centrifuge for solid-liquid separation. In order to prevent the centrifuge from scaling, a spray cleaning device is set to clean the inside of the drum, the outside of the drum and the discharge port. The separated solids are slurried (for easy transportation, etc.) and transported to the primary neutralization tank. The calcium oxide and calcium hydroxide in the slurry neutralize the mother liquor of sulfate newly entering the primary neutralization tank. After neutralization, it is filtered through the primary filter tank to obtain a neutral calcium sulfate slag, so that the calcium oxide and calcium hydroxide can be reused. The existing "pH value of the filtered waste residue (i.e. calcium sulfate) is too high" is also caused by the presence of calcium oxide and calcium hydroxide.

[0051] The present invention adopts secondary neutralization to reduce the pH value of the by-product calcium sulfate slag, so that it can be processed as a resource, while reducing the consumption of calcium oxide and saving costs. The process is improved from the original manual intermittent operation to automated unmanned continuous operation. It relieves the employment pressure of enterprises and reduces staff and increases efficiency. The production process has a fully enclosed structure, and the on-site environment has been greatly improved, reducing environmental air pollution. The whole system runs automatically and continuously, which improves production capacity and saves electricity and energy consumption. The equipment is streamlined and the site utilization rate is greatly improved. The continuous operation is stable, the production process indicators are stable and controllable, and the solid content and pulping concentration of the effluent are better than the original manual intermittent operation.

[0052] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A pretreatment system for high-salinity ammonia-containing wastewater, characterized in that: The system comprises a sulfate mother liquid storage tank (8), a primary neutralization tank, a primary filtering tank, a secondary neutralization tank and a horizontal spiral centrifuge (1) which are connected in sequence, wherein the solid phase discharge port of the horizontal spiral centrifuge (1) is connected to the primary neutralization tank via a pulping mechanism, and a spray cleaning device is installed at the drum and the solid phase discharge end of the horizontal spiral centrifuge (1).

2. A pretreatment system for high-salinity ammonia-containing wastewater according to claim 1, characterized in that: The liquid phase water outlet of the horizontal spiral centrifuge (1) is connected to a sedimentation tank (2) via a clear liquid valve (11); the sedimentation outlet of the sedimentation tank (2) is connected to the inlet of a stock tank (3) containing a flocculant via a sedimentation tank pump (21); the outlet of the stock tank (3) is connected to the horizontal spiral centrifuge (1); and the liquid phase water outlet of the horizontal spiral centrifuge (1) is also connected to a primary neutralization tank via a mixed liquid valve (12).

3. A pretreatment system for high-salinity ammonia-containing wastewater according to claim 1, characterized in that: The beating mechanism comprises a beating tank A (41), a beating tank B (42) and a slurry storage tank (5) which are connected in sequence, the feed port of the beating tank A (41) is connected to the solid phase discharge port of the horizontal spiral centrifuge (1), the discharge port of the beating tank A (41) is connected to the feed port of the beating tank B (42), the discharge port of the beating tank B (42) is connected to the feed port of the slurry storage tank (5), and the discharge port of the slurry storage tank (5) is connected to the primary neutralization tank.

4. A pretreatment system for high-salinity ammonia-containing wastewater according to claim 1, characterized in that: The liquid inlet end of the spray cleaning device is respectively connected to a sulfate mother liquid storage tank (8), a nitric acid storage tank (7) and a tap water pipe (10).

5. A pretreatment system for high-salinity ammonia-containing wastewater according to claim 1, characterized in that: The feed port of the pulping tank A (41) is connected to the pulping rehydration tank (6) via a pulping rehydration pump (61).

6. A pretreatment system for high-salinity ammonia-containing wastewater according to claim 5, characterized in that: The outlet of the pulping and replenishing pump (61) is equipped with a flow meter; the pulping tank B (42) is equipped with a radar level meter (43), and both the flow meter and the radar level meter (43) are connected to the PLC control box.

7. A pretreatment system for high-salinity ammonia-containing wastewater according to claim 2, characterized in that: The horizontal spiral centrifuge (1), the sedimentation tank (2), the pulp tank (3) and the pulping mechanism are all connected to the absorption tower (9) via a negative pressure absorption pipe.

8. A method for pretreating high-salinity ammonia-containing wastewater, characterized in that: The sewage is treated by using the pretreatment system described in any one of claims 1 to 7, and the specific steps are as follows: S1, taking a pool of sulfate mother liquor to be treated and passing it into a secondary neutralization tank, and adding calcium oxide into the secondary neutralization tank until the pH value of the wastewater reaches 11.3, the neutralized wastewater is passed into a horizontal spiral centrifuge (1) for centrifugation, and the solid phase after centrifugation is passed into a pulping mechanism and then into a primary neutralization tank; S2, the remaining sulfate mother liquor to be treated is passed into a primary neutralization tank, and then flows through a primary filtration tank, a secondary neutralization tank, and a horizontal spiral centrifuge (1) in sequence. The solid phase after centrifugation in the horizontal spiral centrifuge (1) is passed into a pulping mechanism and then transported to the primary neutralization tank. The liquid phase after centrifugation is passed into a sedimentation tank (2). The clear liquid at the top of the sedimentation tank (2) overflows to the next stripping section. The solid phase precipitated in the sedimentation tank (2) is passed into a raw pulp tank (3) for flocculation and then passed into the horizontal spiral centrifuge (1).

9. A method for pretreating high-salt ammonia-containing wastewater according to claim 8, characterized in that: In step S1, in the first 3 minutes, the mixed liquid valve (12) at the liquid phase outlet of the horizontal spiral centrifuge (1) is opened, the clear liquid valve (11) is closed, and the liquid phase after centrifugation is passed into a primary neutralization tank. After 3 minutes, the clear liquid valve (11) at the liquid phase outlet of the horizontal spiral centrifuge (1) is opened, the mixed liquid valve (12) is closed, and the liquid phase after centrifugation is passed into a sedimentation tank (2). The clear liquid at the top of the sedimentation tank (2) overflows to the next stripping section. The solid phase precipitated in the sedimentation tank (2) is passed into a raw pulp tank (3) for flocculation and then passed into the horizontal spiral centrifuge (1). In step S2, the clear liquid valve (11) at the liquid phase outlet of the horizontal spiral centrifuge (1) is opened, and the mixed liquid valve (12) is closed.

10. The method for pretreating high-salinity ammonia-containing wastewater according to claim 8, characterized in that: Before step S1, the spray cleaning device is turned on.

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