A method for recycling tailings from production of high-polymerization degree ammonium polyphosphate

Abstract

The invention discloses a method for recycling tailings of ammonium polyphosphate production with high polymerization degree, comprising the following steps: S1: adding water to a reactor and putting in ammonium polyphosphate tailings; S2: slowly adding phosphoric acid from the bottom for incomplete hydrolysis reaction; S3: neutralizing with ventilation ammonia, and controlling the temperature to be lower than 60 degrees during neutralization; S4: the pH of the system to be reacted is 6.0-7.0, stopping ventilation ammonia, and obtaining an ammonium polyphosphate hydrolyzate; S5: after filtering the hydrolyzate, the filtrate is pumped to a storage tank; S6: the liquid in the storage tank is sent to the crop reactant of the ammonium polyphosphate liquid fertilizer production line. The present application invention hydrolyzes it by adding acid to generate a low-polymerization ammonium polyphosphate product that can be used as a liquid fertilizer containing ammonium polyphosphate, and finally realizes the full dissolution of effective materials without bringing in invalid impurities into the water-based fertilizer.

Description

Technical Field

[0001] The present application particularly relates to a method for recycling tailings from the production of high-polymerization degree ammonium polyphosphate. Background Art

[0002] The tailings generated during the production of high-polymerization ammonium polyphosphate have low whiteness, water solubility, and polymerization degree distribution, which cannot meet the requirements of flame retardants. Directly returning them to ammonium polyphosphate flame retardant products will affect product quality. Generally, they are treated as waste together with ammonium polyphosphate sweeping materials. Summary of the invention

[0003] In view of the above-mentioned defects, the present application provides a method for recycling high-polymerization degree ammonium polyphosphate production tailings, which hydrolyzes the high-polymerization degree ammonium polyphosphate production tailings by adding acid to generate a low-polymerization degree ammonium polyphosphate product that can be used in the production of ammonium polyphosphate-containing liquid fertilizer.

[0004] A method for recycling tailings from the production of high-polymerization ammonium polyphosphate comprises the following steps:

[0005] S1: Add water into the reactor and put in the ammonium polyphosphate tailings;

[0006] S2: slowly adding phosphoric acid from the bottom to perform an incomplete hydrolysis reaction;

[0007] S3: Ventilation ammonia neutralization, the temperature during neutralization is controlled below 60 degrees;

[0008] S4: When the pH of the reaction system reaches 6.0-7.0, stop aerating ammonia to obtain an ammonium polyphosphate hydrolyzate;

[0009] S5: After the hydrolyzate is filtered, the filtrate is pumped to a storage tank;

[0010] S6: The liquid in the storage tank is fed into the ammonium polyphosphate liquid fertilizer production line as crop reactant.

[0011] In one or more optional embodiments of the present invention, in S1, the ratio of ammonium polyphosphate to water is 1:2.5-1:4, and in S2, the mass ratio of phosphoric acid to ammonium polyphosphate is 1:0.8-1:1.5.

[0012] In one or more optional embodiments of the present invention, in S2, with the addition of phosphoric acid, the viscosity in the reaction system gradually increases from low to high, and then decreases from high. When the viscosity of the reaction system decreases from high to less than 200 mPa.s, the hydrolysis reaction is terminated.

[0013] In one or more optional embodiments of the present invention, the high-polymerization ammonium polyphosphate production tailings recycling device includes a reactor and a storage tank, the reactor is provided with a tailings feed port, the tailings feed port is located at the upper part of the reactor, the reactor is respectively connected with other material feed pipes, a post-reaction liquid discharge pipe and a tail gas pipe, one end of the other material feed pipe extends into the bottom of the inner cavity of the reactor, and the other end is located outside the wall of the reactor, the other material feed pipe is located outside the wall of the reactor, and the pipeline is respectively connected with a phosphoric acid feed pipe, an ammonia feed pipe and a reaction water pipe, the other end of the post-reaction liquid discharge pipe is located in the inner cavity of the storage tank, and the bottom of the storage tank is provided with an ammonium polyphosphate liquid fertilizer production line feed pipe.

[0014] In one or more optional embodiments of the present invention, the reactor is provided with a water cooling jacket for controlling the reaction temperature in the reactor, the cooling water inlet end of the water cooling jacket is located at the lower part of the reactor, and the cooling water outlet end of the water cooling jacket is located at the upper part of the reactor.

[0015] In one or more optional embodiments of the present invention, one end of the other material feed pipe located in the inner cavity of the reactor is connected to a horizontal liquid distributor, the reactor is provided with a turbine shearing agitator, and the horizontal liquid distributor is located below the stirring mechanism.

[0016] In one or more optional embodiments of the present invention, the reactor is connected to a first weighing bracket, a first weighing sensor is connected to the lower surface of the first weighing bracket, and the storage tank is connected to a second weighing bracket, a second weighing sensor is connected to the lower surface of the second weighing bracket.

[0017] In one or more optional embodiments of the present invention, the post-reaction liquid discharge pipe is provided with a centrifugal pump, and a submersible agitator is provided in the storage tank.

[0018] In one or more optional embodiments of the present invention, an online pH meter, a pressure sensor, an online viscometer and a temperature sensor are respectively provided in the reactor.

[0019] In one or more optional embodiments of the present invention, the high-polymerization degree ammonium polyphosphate production tailings recycling device is provided with a PLC controller, and pneumatic valves are provided on other material feed pipes, post-reaction liquid discharge pipes, tail gas pipes, cooling water inlet ends and ammonium polyphosphate liquid fertilizer production line feed pipes, and the PLC controller is respectively connected to the pneumatic valve, drive mechanism, first weighing sensor, online pH meter, pressure sensor, online viscometer, temperature sensor, submersible agitator, second weighing sensor, and centrifugal pump.

[0020] Principle and beneficial effects of the invention: The tailings generated during the production of high-polymerization ammonium polyphosphate cannot meet the requirements of flame retardants in terms of whiteness, water solubility, and polymerization degree distribution. Generally, they are treated as waste together with sweeping materials. The polymerization degree of this waste is greater than 1000 and contains polymerized nitrogen and phosphorus elements. The present invention partially hydrolyzes it by adding acid to generate liquid fertilizer containing ammonium polyphosphate for production and use, thereby obtaining a water-soluble fertilizer containing ammonium polyphosphate and improving the utilization efficiency of phosphorus on crops; the high-polymerization ammonium polyphosphate is hydrolyzed by chain breaking under acidic conditions to form low-polymerization ammonium polyphosphate with a polymerization degree of less than 20, which is neutralized by ammonia. As the pH value increases, the hydrolysis tends to become slower. During the neutralization process, the temperature of the water system is controlled to prevent excessive hydrolysis at high temperature, resulting in a low yield of low-polymerization products.

[0021] Glossary

[0022] High-polymerization ammonium polyphosphate - In the present invention, high-polymerization ammonium polyphosphate refers to ammonium polyphosphate with a polymerization degree greater than 1000.

[0023] Low-polymerization ammonium polyphosphate - In the present invention, low-polymerization ammonium polyphosphate refers to ammonium polyphosphate with a polymerization degree of less than 50. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of the high-polymerization ammonium polyphosphate production tailings recycling device of this application;

[0025] In the figure: 1, reactor, 11, water cooling jacket, 111, cooling water inlet, 112, cooling water outlet, 12, stirring system, 121, stirring mechanism, 122, rotating shaft, 123, driving mechanism, 13, tail material feed port, 14, phosphoric acid feed pipe, 15, gas ammonia feed pipe, 16, reaction water pipe, 17, liquid discharge pipe after reaction, 18, tail gas pipe, 191, horizontal liquid distributor, 192, first weighing bracket, 193, first weighing sensor, 194, online pH meter, 195, pressure sensor, 196, online viscometer, 197, temperature sensor, 2, storage tank, 21, ammonium polyphosphate liquid fertilizer production line feed pipe, 22, breathing valve, 23, submersible agitator, 24, second weighing bracket, 25, second weighing sensor, 3, first filter, 4, centrifugal pump, 5, second filter. DETAILED DESCRIPTION

[0026] The present application will be further described below.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inner", "outer", "front", "back", "top", "bottom" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the inventive product is usually placed when in use, and are only for the convenience of describing the present invention 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 limiting the present invention. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed", "opened", "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] A method for recycling tailings from the production of high-polymerization ammonium polyphosphate comprises the following steps:

[0030] S1: Add water to the reactor, add ammonium polyphosphate tailings (polymerization degree 1000-2000), stir evenly, and the ratio of ammonium polyphosphate to water is 1:2.5-1:4;

[0031] S2: Start stirring, slowly add phosphoric acid from the bottom to perform incomplete hydrolysis reaction, the mass ratio of phosphoric acid to ammonium polyphosphate is 1:0.8-1:1.5, and avoid patina when adding materials. In the hydrolysis reaction of this step, with the addition of phosphoric acid, the viscosity in the reaction system gradually increases from low to high, and then decreases from high. When the viscosity of the reaction system decreases from high to less than 200mPa.s, the hydrolysis reaction is terminated.

[0032] S3: Ventilate ammonia for neutralization, and control the temperature below 60 degrees during neutralization. During neutralization, when the temperature is higher than 50 degrees, reduce the ammonia flow rate.

[0033] S4: When the pH of the reaction system reaches 6.0-7.0, stop aerating ammonia to obtain ammonium polyphosphate hydrolyzate.

[0034] S5: After the hydrolyzate is filtered, the filtrate is pumped to a storage tank. The filter residue is impurities and solid ammonium polyphosphate. The degree of polymerization of the ammonium polyphosphate hydrolyzate after filtration is less than 20.

[0035] S6: The liquid in the storage tank is fed into the ammonium polyphosphate liquid fertilizer production line as crop reactant.

[0036] In the following Examples 1-3 and Comparative Examples 1-2, the phosphoric acid is 85.0% industrial phosphoric acid. Ammonium polyphosphate tailings: degree of polymerization 1300, polyphosphate content (in terms of P2O5) 72.54%.

[0037] Example 1

[0038] S1: Add 1200 kg of water into the reactor, put in 400 kg of ammonium polyphosphate tailings, and stir evenly;

[0039] S2: start stirring, slowly add 320 kg of phosphoric acid from the bottom to carry out hydrolysis reaction, when adding material, should avoid cladding, stirring is stirring at normal temperature. In this step hydrolysis reaction, along with the addition of phosphoric acid, the viscosity in the reaction system gradually increases from low, and then decreases from high, when the reaction system is reduced from high to less than 200mPa.s in viscosity, the hydrolysis reaction is terminated.

[0040] S3: Ventilate ammonia for neutralization. Turn on water cooling during neutralization and control the temperature below 60 degrees. During neutralization, when the temperature is higher than 50 degrees, reduce the ammonia flow rate.

[0041] S4: When the pH of the reaction system reaches 6.3, stop aerating ammonia to obtain ammonium polyphosphate hydrolyzate.

[0042] S5: After the hydrolyzate is filtered, the filtrate is pumped to a storage tank to obtain 1926 kg of filtrate, and the polyphosphate content (in terms of P 2 O 5 The total amount was 11.89%, and the polyphosphate recovery rate was 78.92%.

[0043] S6: The liquid in the storage tank is fed into the ammonium polyphosphate liquid fertilizer production line as crop reactant.

[0044] Example 2

[0045] S1: Add 1200 kg of water and 400 kg of ammonium polyphosphate tailings into the reactor and stir evenly;

[0046] S2: start stirring, slowly add 600 kg of phosphoric acid from the bottom to carry out hydrolysis reaction, when adding material, should avoid cladding, stirring is stirring at normal temperature. In this step hydrolysis reaction, along with the addition of phosphoric acid, the viscosity in the reaction system gradually increases from low, and then decreases from high, when the reaction system is reduced from high to less than 200mPa.s in viscosity, the hydrolysis reaction is terminated.

[0047] S3: Ventilate ammonia for neutralization. Turn on water cooling during neutralization and control the temperature below 60 degrees. During neutralization, when the temperature is higher than 50 degrees, reduce the ammonia flow rate.

[0048] S4: When the pH of the reaction system reaches 6.5, stop aerating ammonia to obtain ammonium polyphosphate hydrolyzate.

[0049] S5: After the hydrolyzate is filtered, the filtrate is pumped to a storage tank to obtain 2311 kg of filtrate, and the polyphosphate content (in terms of P 2 O 5 The total amount of phosphorus was 9.45%, and the polyphosphate recovery rate was 75.98%.

[0050] S6: The liquid in the storage tank is fed into the ammonium polyphosphate liquid fertilizer production line as crop reactant.

[0051] Example 3

[0052] S1: Add 1200 kg of water into the reactor, put in 400 kg of ammonium polyphosphate tailings, and stir evenly;

[0053] S2: start stirring, slowly add 400 kg of phosphoric acid from the bottom to carry out hydrolysis reaction, when adding material, should avoid cladding, stirring is stirring at normal temperature. In this step hydrolysis reaction, along with the addition of phosphoric acid, the viscosity in the reaction system gradually increases from low, and then decreases from high, when the reaction system is reduced from high to the viscosity less than 200mPa.s, the hydrolysis reaction is terminated.

[0054] S3: Ventilate ammonia for neutralization. Turn on water cooling during neutralization and control the temperature below 60 degrees. During neutralization, when the temperature is higher than 50 degrees, reduce the ammonia flow rate.

[0055] S4: When the pH of the reaction system reaches 6.3, stop aerating ammonia to obtain ammonium polyphosphate hydrolyzate.

[0056] S5: After the hydrolyzate is filtered, the filtrate is pumped to a storage tank to obtain 2062 kg of filtrate, and the polyphosphate content (in terms of P 2 O 5 The total amount of phosphorus was 12.87%, and the polyphosphate recovery rate was 91.46%.

[0057] S6: The liquid in the storage tank is fed into the ammonium polyphosphate liquid fertilizer production line as crop reactant.

[0058] Comparative Example 1

[0059] S1: Add 1200 kg of water into the reactor, put in 400 kg of ammonium polyphosphate tailings, and stir evenly;

[0060] S2: Start stirring, slowly add 200 kg of phosphoric acid from the bottom to carry out hydrolysis reaction, when adding material, should avoid cladding, stirring is stirring at normal temperature. In this step hydrolysis reaction, with the addition of phosphoric acid, the viscosity in the reaction system gradually increases from low, and then decreases from high, when the reaction system is reduced from high to less than 200mPa.s in viscosity, the hydrolysis reaction is terminated.

[0061] S3: Ventilate ammonia for neutralization, and control the temperature below 60 degrees during neutralization. During neutralization, when the temperature is higher than 50 degrees, reduce the ammonia flow rate.

[0062] S4: When the pH of the reaction system reaches 6.3, stop aerating ammonia to obtain ammonium polyphosphate hydrolyzate. Most of the ammonium polyphosphate product is in a solid state and suspended in the liquid.

[0063] S5: After the hydrolyzate is filtered, the filtrate is pumped to a storage tank to obtain 1683 kg of filtrate, and the polyphosphate content (in terms of P 2 O 5 The hydrolysis yield was low, and most of the solids were not hydrolyzed and entered the filter cake.

[0064] S6: The liquid in the storage tank is supplemented with fertilizer-grade ammonium polyphosphate and then fed into the ammonium polyphosphate liquid fertilizer production line as a crop reactant.

[0065] Comparative Example 2

[0066] S1: Add 1200 kg of water into the reactor, put in 400 kg of ammonium polyphosphate tailings, and stir evenly;

[0067] S2: start stirring, slowly add 700 kg of phosphoric acid from the bottom to carry out hydrolysis reaction, when adding material, should avoid cladding, stirring is stirring at normal temperature. In this step hydrolysis reaction, along with the addition of phosphoric acid, the viscosity in the reaction system gradually increases from low, and then decreases from high, when the reaction system is reduced from high to less than 200mPa.s in viscosity, the hydrolysis reaction is stopped.

[0068] S3: Ventilate ammonia for neutralization, and control the temperature below 60 degrees during neutralization. During neutralization, when the temperature is higher than 50 degrees, reduce the ammonia flow rate.

[0069] S4: When the pH of the reaction system reaches 6.3, stop aerating ammonia to obtain ammonium polyphosphate hydrolyzate.

[0070] S5: After the hydrolyzate is filtered, the filtrate is pumped to a storage tank to obtain 2417 kg of filtrate. The polyphosphate content (in terms of P 2 O 5 The hydrolysis yield was low, and the water was partially hydrolyzed into orthophosphate.

[0071] S6: The liquid in the storage tank is supplemented with fertilizer-grade ammonium polyphosphate and then fed into the ammonium polyphosphate liquid fertilizer production line as a crop reactant.

[0072] Comparative Example 3

[0073] S1: Add 1200 kg of water into the reactor, put in 400 kg of ammonium polyphosphate tailings, and stir evenly;

[0074] S2: Start stirring, slowly add 400 kg of phosphoric acid from the bottom to carry out complete hydrolysis reaction, when adding materials, avoid slurrying, stirring is stirring at room temperature. In this step, with the addition of phosphoric acid, the viscosity in the reaction system gradually increases from low, and then decreases from high until the viscosity does not change, stopping the hydrolysis reaction.

[0075] S3: Ventilate ammonia for neutralization, and control the temperature below 60 degrees during neutralization. During neutralization, when the temperature is higher than 50 degrees, reduce the ammonia flow rate.

[0076] S4: When the pH value of the reaction system reaches 6.3, stop aerating ammonia to obtain a hydrolyzate. The hydrolyzate does not contain ammonium polyphosphate and is an ammonium phosphate hydrolyzate, which cannot be used for the production of ammonium polyphosphate liquid fertilizer.

[0077] Please refer to Figure 1 , Figure 1 The present invention is a schematic diagram of the structure of the device for implementing the above-mentioned method for recycling tailings from the production of high-polymerization degree ammonium polyphosphate.

[0078] A high-polymerization ammonium polyphosphate production tailings recycling device comprises a reactor 1 and a storage tank 2, wherein the reactor 1 is provided with a tailings feed port 13, the tailings feed port 13 is located at the upper part of the reactor 1, and the reactor 1 is respectively connected with other material feed pipes, a post-reaction liquid discharge pipe 17 and a tail gas pipe 18, one end of the other material feed pipe extends into the bottom of the inner cavity of the reactor 1, and the other end is located outside the wall of the reactor 1, and the other material feed pipe is located outside the wall of the reactor 1. The pipes are respectively connected with a phosphoric acid feed pipe 14, a gas ammonia feed pipe 15 and a reaction water pipe 16, the other end of the post-reaction liquid discharge pipe 17 is located in the inner cavity of the storage tank 2, and the bottom of the storage tank 2 is provided with an ammonium polyphosphate liquid fertilizer production line feed pipe 21. The tail gas pipe 18 is used to discharge the ammonia overflowed during the reaction from the tail gas pipe 18 to prevent the ammonia from overflowing from other places and causing safety accidents.

[0079] In one or more specific embodiments of the present invention, the reactor 1 is connected to a first weighing bracket 192, a first weighing sensor 193 is connected to the lower surface of the first weighing bracket 192, and the storage tank 2 is connected to a second weighing bracket 24, and a second weighing sensor 25 is connected to the lower surface of the second weighing bracket 24. After the first weighing bracket 192, the first weighing sensor 193, the second weighing bracket 24 and the second weighing sensor 25 are set, when in use, the first weighing bracket 192 and the second weighing bracket 24 are placed on the platform, and through the first weighing sensor 193 and the second weighing sensor 25, the operator can pay attention to the weight changes of the reactor 1 and the storage tank 2 at any time, know how much reaction material is added, how much product is produced, and facilitate accurate reaction control.

[0080] In one or more specific embodiments of the present invention, the reactor 1 is provided with a water cooling jacket 11 for controlling the reaction temperature in the reactor 1 , the cooling water inlet end 111 of the water cooling jacket 11 is located at the lower part of the reactor 1 , and the cooling water outlet end 112 of the water cooling jacket 11 is located at the upper part of the reactor 1 .

[0081] In one or more specific embodiments of the present invention, the water cooling jacket 11 is a spiral water cooling jacket 11 .

[0082] In one or more specific embodiments of the present invention, the reactor 1 is provided with a stirring system 12, which is used to evenly distribute the liquid in the reactor 1. The stirring system 12 includes a driving mechanism 123, a rotating shaft 122 and a stirring mechanism 121. The driving mechanism 123 is located outside the reactor wall of the reactor 1, and the stirring mechanism 121 is located in the inner cavity of the reactor wall of the reactor 1. One end of the rotating shaft 122 is connected to the driving mechanism 123, and the other end is connected to the stirring mechanism 121. The driving mechanism 123 can be an electrically driven motor or a hydraulically driven hydraulic cylinder. The driving mechanism 123 is preferably an explosion-proof motor.

[0083] In one or more specific embodiments of the present invention, the local viscosity of the ammonium polyphosphate suspension will rise sharply after encountering phosphoric acid, causing patina and uneven reaction. Therefore, the other material feed pipes of the present application are located at one end of the inner cavity of the reactor 1 and are connected to a horizontal liquid distributor 191, and the horizontal liquid distributor 191 is located below the stirring mechanism 121, and the stirring mechanism 121 is a turbine shearing agitator. The phosphoric acid of the present invention flows in evenly from the lower part of the stirring blade of the turbine shearing agitator, and the turbine shearing agitator stirs. While ensuring the circulation of the system, the shearing function is increased, and the phosphoric acid is quickly dispersed. At the same time, the high-viscosity material near the phosphoric acid distribution port is quickly sheared and dispersed, ensuring the uniform reaction of the system. The liquid enters the reactor 1 from below the stirring liquid. The liquid distributor and the turbine shearing agitator finally solve the problem of patina.

[0084] In one or more specific embodiments of the present invention, a first filter 3 and a centrifugal pump 4 are provided on the post-reaction liquid discharge pipe 17 , and a second filter 5 is provided on the ammonium polyphosphate liquid fertilizer production line feed pipe 21 .

[0085] In one or more specific embodiments of the present invention, in order to observe the pH, pressure, viscosity and temperature in the reactor 1 at any time, an online pH meter 194, a pressure sensor 195, an online viscometer 196 and a temperature sensor 197 are respectively provided in the reactor 1. The pressure sensor 195 is used to control the pressure in the reactor to ensure that the pressure in the reactor is slightly negative pressure, which is convenient for smooth introduction of gaseous ammonia.

[0086] In one or more specific embodiments of the present invention, a breathing valve 22 is disposed on the top of the storage tank 2 , and a submersible mixer 23 is disposed inside the storage tank 2 .

[0087] In one or more specific embodiments of the present invention, an explosion-proof axial flow fan is installed on the tail gas pipe 18 .

[0088] In one or more specific embodiments of the present invention, a high-polymerization ammonium polyphosphate production tailings recycling device is provided with a PLC controller, and other material feed pipes, a post-reaction liquid discharge pipe 17, a tail gas pipe 18, a cooling water inlet end 111, and an ammonium polyphosphate liquid fertilizer production line feed pipe 21 are provided with pneumatic valves, and the PLC controller is respectively connected to the pneumatic valve, a drive mechanism 123, a first weighing sensor 193, an online pH meter 194, a pressure sensor 195, an online viscometer 196, a temperature sensor 197, a submersible agitator 23, a second weighing sensor 25, and a centrifugal pump 4. Through the control of the PLC controller, in addition to the tailings feeding, the automatic control of the entire process can be achieved. It should be known to those skilled in the art that the PLC controller is not the invention point of the present application, and the PLC controller is purchased from the market.

[0089] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for recycling tailings from the production of high-polymerization ammonium polyphosphate, comprising the following steps: S1: adding water into a reactor and adding ammonium polyphosphate tailings, wherein the degree of polymerization of the ammonium polyphosphate is greater than 1000; S2: starting stirring, stirring at room temperature, slowly adding phosphoric acid from the bottom to perform an incomplete hydrolysis reaction, with the addition of phosphoric acid, the viscosity in the reaction system gradually increases from low to high, and then decreases from high, when the viscosity of the reaction system decreases from high to less than 200 mPa·s, the hydrolysis reaction is terminated; S3: Ventilation ammonia neutralization, water cooling is turned on during neutralization, and the temperature is controlled below 60 degrees during neutralization; S4: When the pH of the reaction system reaches 6.0-7.0, stop aerating ammonia to obtain an ammonium polyphosphate hydrolyzate; S5: After the hydrolyzate is filtered, the filtrate is pumped to a storage tank; S6: The liquid in the storage tank is fed into the ammonium polyphosphate liquid fertilizer production line as a reactant.

2. The method for recycling tailings from the production of high-polymerization ammonium polyphosphate according to claim 1, characterized in that: In the S1, the mass ratio of ammonium polyphosphate to water is 1:2.5-1:4, and in S2, the mass ratio of phosphoric acid to ammonium polyphosphate is 1:0.8-1:1.

5.

3. The method for recycling tailings of high-polymerization ammonium polyphosphate production according to any one of claims 1-2, characterized in that: The high-polymerization degree ammonium polyphosphate production tailings recycling device used in the high-polymerization degree ammonium polyphosphate production tailings recycling method comprises a reactor and a storage tank, the reactor is provided with a tailings feed port, the tailings feed port is located at the upper part of the reactor, the reactor is respectively connected with other material feed pipes, a post-reaction liquid discharge pipe and a tail gas pipe, one end of the other material feed pipe extends into the bottom of the inner cavity of the reactor, and the other end is located outside the wall of the reactor, the other material feed pipe is located outside the wall of the reactor, and the pipeline is respectively connected with a phosphoric acid feed pipe, a gas ammonia feed pipe and a reaction water pipe, and the other end of the post-reaction liquid discharge pipe is located in the inner cavity of the storage tank; the bottom of the storage tank is provided with an ammonium polyphosphate liquid fertilizer production line feed pipe.

4. The method for recycling tailings of high-polymerization ammonium polyphosphate production according to claim 3, characterized in that: The reactor is provided with a water cooling jacket for controlling the reaction temperature in the reactor, the cooling water inlet end of the water cooling jacket is located at the lower part of the reactor, and the cooling water outlet end of the water cooling jacket is located at the upper part of the reactor.

5. The method for recycling tailings of high-polymerization ammonium polyphosphate production according to any one of claims 3-4, characterized in that: One end of the other material feed pipe located in the inner cavity of the reactor is connected to a horizontal liquid distributor. The reactor is provided with a turbine shearing agitator, and the horizontal liquid distributor is located below the stirring mechanism.

6. The method for recycling tailings from production of high-polymerization ammonium polyphosphate according to any one of claims 3 to 5, characterized in that: The reactor is connected to a first weighing bracket, a first weighing sensor is connected to the lower surface of the first weighing bracket, and the storage tank is connected to a second weighing bracket, a second weighing sensor is connected to the lower surface of the second weighing bracket.

7. The method for recycling tailings from production of high-polymerization ammonium polyphosphate according to any one of claims 3 to 6, characterized in that: The post-reaction liquid discharge pipe is provided with a centrifugal pump, and the storage tank is provided with a submersible agitator.

8. The method for recycling tailings from production of high-polymerization ammonium polyphosphate according to claim 6, characterized in that: An online pH meter, a pressure sensor, an online viscometer and a temperature sensor are respectively arranged in the reactor.

9. The method for recycling tailings from production of high-polymerization ammonium polyphosphate according to any one of claims 7-8, characterized in that: The high-polymerization degree ammonium polyphosphate production tail material recycling device is provided with a PLC controller, and pneumatic valves are provided on other material feed pipes, a post-reaction liquid discharge pipe, a tail gas pipe, a cooling water inlet end and an ammonium polyphosphate liquid fertilizer production line feed pipe. The PLC controller is respectively connected to the pneumatic valve, a drive mechanism, a first weighing sensor, an online pH meter, a pressure sensor, an online viscometer, a temperature sensor, a submersible agitator, a second weighing sensor, and a centrifugal pump.

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