An apparatus and method for preparing battery-grade iron phosphate based on a jet reactor

Abstract

This invention provides an apparatus and method for preparing battery-grade iron phosphate based on a jet reactor, belonging to the field of new energy material preparation. The apparatus includes a mixing tank, a jet loop oxidation reactor I, a jet loop oxidation reactor II, a gas-liquid separation tank, a jet loop precipitation reactor I, a jet loop precipitation reactor II, a jet washing tank I, a vacuum filter I, a jet washing tank II, a vacuum filter II, and a flash dryer. The jet reactor can form a sufficient gas-liquid (solid) mixing zone, effectively promoting heat transfer, mass transfer, and momentum transfer, thereby enhancing the reaction and improving the reaction rate and product yield. The battery-grade iron phosphate (FePO4·2H2O) prepared using steelmaking dust conforms to the HG / T 4701-2014 standard. This invention features mature technology, advanced equipment, continuous operation, high degree of automation, shortened reaction time, energy saving, improved production efficiency, and the transformation of steelmaking dust from waste into valuable resources, making it environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of new energy material preparation, specifically relating to an apparatus and method for preparing battery iron phosphate based on a jet reactor. Background Technology

[0002] my country has a large steel production volume, and on average, about 1% of the steel produced emits iron-containing dust, resulting in annual emissions of tens of millions of tons of this dust. Currently, the comprehensive utilization rate of these solid wastes is less than 20%, with most being stockpiled in factory areas. This not only occupies a large amount of land resources but also causes serious pollution to the factory area and surrounding environment due to the flying dust. The iron in steelmaking dust is predominantly trivalent iron (Fe3+). The typical composition of the sulfuric acid solution from steelmaking dust is 20g / L–25g / L sulfuric acid, 160g / L–180g / L ferrous sulfate, and 70g / L–80g / L ferrous sulfate. Using the iron resources in the sulfuric acid solution from steelmaking dust as the iron source for ferric phosphate production achieves resource recovery and utilization, to a certain extent realizing the goal of turning waste into treasure and reducing costs and increasing efficiency.

[0003] Meanwhile, during steel processing, acid is typically added to treat the oxide film on the surface, generating a large amount of pickling wastewater. Steel pickling wastewater is characterized by its strong acidity and high content of heavy metal ions, making it a difficult-to-treat industrial wastewater that cannot be directly discharged without treatment. Millions of tons of pickling wastewater are generated nationwide annually. The typical composition of pickling wastewater is 50g / L–60g / L sulfuric acid and 220g / L–230g / L ferrous sulfate. Using the iron resources in the steel pickling wastewater as the iron source for ferric phosphate production achieves resource recovery and utilization, to a certain extent realizing the goal of turning waste into treasure and reducing costs and increasing efficiency.

[0004] The industrial production methods for battery-grade iron phosphate generally include six processes: sodium process, ammonium process, iron powder process, fertilizer phosphoric acid process, iron oxide red process, and dicalcium phosphate process. Most of these processes employ batch processes, which cannot guarantee batch-to-batch stability and consistency. Furthermore, batch production equipment involves numerous reaction vessels, large floor space requirements, high material and energy consumption, low heat and mass transfer efficiency, numerous operating units, long reaction cycles, and high labor costs. The increased energy and material consumption in the battery-grade iron phosphate production process leads to higher costs, hindering industrial-scale production.

[0005] There is an urgent need in this field to find a low-energy-consumption, environmentally friendly process and equipment for preparing iron phosphate for batteries that can overcome the above-mentioned technical problems. Summary of the Invention

[0006] To address the aforementioned engineering problems and market demands, and to overcome the limitations of existing technologies, this invention provides an apparatus and method for preparing battery-grade iron phosphate based on a jet reactor. This invention features mature technology, advanced equipment, continuous operation, high automation, shortened reaction time, energy saving, improved production efficiency, and environmental friendliness.

[0007] The technical solution adopted by the present invention to solve its technical problem is: an apparatus for preparing battery iron phosphate based on a jet reactor, comprising a batching tank, a jet loop oxidation reactor I, a jet loop oxidation reactor II, a gas-liquid separation tank, a jet loop precipitation reactor I, a jet loop precipitation reactor II, a jet washing tank I, a vacuum filter I, a jet washing tank II, a vacuum filter II, and a flash dryer connected in sequence.

[0008] The mixing tank is used to mix the catalyst and iron source solution evenly. After the mixture reaches the reaction temperature, it enters the jet loop oxidation reactor I. The jet loop oxidation reactor I and jet loop oxidation reactor II are used to carry out the oxidation reaction, that is, to oxidize the ferrous sulfate in the iron source solution into ferric sulfate. The oxidized liquid after the oxidation reaction in jet loop oxidation reactor II enters the gas-liquid separator. The gas-liquid separator is used to separate the unreacted oxygen in the oxidized liquid. The oxidized liquid with separated oxygen enters the jet loop precipitation reactor I. The jet loop precipitation reactor I and jet loop precipitation reactor II are used to precipitate the ferric sulfate solution to generate ferric phosphate. The slurry liquid after the reaction in jet loop precipitation reactor II enters the jet washing tank I. The slurry liquid after the reaction is washed, separated into solid and liquid, and dried by jet washing tank I, vacuum filter I, jet washing tank II, vacuum filter II, and flash dryer to obtain ferric phosphate.

[0009] Furthermore, the device structure is specifically device one or device two;

[0010] Device 1:

[0011] The jet loop oxidation reactor I, jet loop oxidation reactor II, jet loop sedimentation reactor I, jet loop sedimentation reactor II, jet scrubbing tank I, and jet scrubbing tank II all use jet injectors for gas-liquid-solid mixing.

[0012] The jet generator includes a coupler and an ejector. The coupler is equipped with a power fluid inlet and a gas / liquid inlet. The outer walls of the batching tank, jet loop oxidation reactor I, jet loop oxidation reactor II, gas-liquid separator, jet loop sedimentation reactor I, jet loop sedimentation reactor II, jet washing tank I, and jet washing tank II are all fitted with jackets for introducing a heat medium for heating. Each of the jet loop oxidation reactor I, jet loop oxidation reactor II, jet loop sedimentation reactor I, and jet loop sedimentation reactor II is equipped with a heat exchanger. The material in the reactor is pumped to the heat exchanger for heating before entering the coupler.

[0013] Device 2:

[0014] A jet tube oxidation reactor is also provided between the batching tank and the jet loop oxidation reactor I. The jet tube oxidation reactor is used for the oxidation of ferrous sulfate in the iron source solution. The jet tube oxidation reactor, jet loop oxidation reactor I, jet loop oxidation reactor II, jet loop precipitation reactor I, jet loop precipitation reactor II, jet washing tank I, and jet washing tank II all use jet injectors for gas-liquid-solid mixing.

[0015] The jet-tube oxidation reactor includes an ejector, a jet impact chamber, and a tubular reactor; the jet impact chamber has an ellipsoidal structure, and the tubular reactor has an arc-shaped structure; the ejector is symmetrically arranged at both ends of the jet impact chamber, and the jet impact chamber is connected to the inner cavity of the tubular reactor; the outer wall of the tubular reactor is provided with a jacket; the jacket is used to introduce a heat medium for heating.

[0016] The jet generator includes a coupler and an ejector. The coupler is provided with a power fluid inlet and a gas / liquid inlet. The mixing tank, jet loop oxidation reactor I, jet loop oxidation reactor II, gas-liquid separator, jet loop sedimentation reactor I, jet loop sedimentation reactor II, jet washing tank I, and jet washing tank II are all equipped with jackets on their outer walls. The jet loop oxidation reactor I, jet loop oxidation reactor II, jet loop sedimentation reactor I, and jet loop sedimentation reactor II are all equipped with heat exchangers. The material in the reactor is transported to the heat exchanger by a fluid pump, heated, and then enters the coupler.

[0017] Furthermore, the device one or device two also includes an oxygen buffer tank, which is used to supply oxygen to the oxidation reactor in the device. The condenser of the gas-liquid separator is connected to the jet loop oxidation reactor I and the jet loop oxidation reactor II, and the oxygen in the condenser enters the jet loop oxidation reactor I and the jet loop oxidation reactor II.

[0018] Furthermore, in the first or second device, both the jet washing tank I and the jet washing tank II are equipped with a mother liquor buffer tank. The mother liquor buffer tank is used to collect the mother liquor separated by the vacuum filter I and the vacuum filter II, respectively. The mother liquor collected by the mother liquor buffer tank of the jet washing tank I is used for ammonium salt recovery, and the mother liquor collected by the mother liquor buffer tank of the jet washing tank II is used for filter cake washing of the vacuum filter I.

[0019] Both jet washing tank I and jet washing tank II are equipped with washing water buffer tanks. The washing water buffer tanks are used to collect the washing water from vacuum filter I and vacuum filter II, respectively. The collected washing water then enters jet washing tank I and jet washing tank II, respectively.

[0020] The present invention also provides a method for preparing battery-grade iron phosphate based on the above-mentioned apparatus, specifically comprising the following steps:

[0021] (1) Steelmaking flue dust acid solution and catalyst are added to the batching tank and mixed evenly under the action of mechanical stirring; the mixture reaches the reaction temperature under the heating of the heat medium and enters the jet loop oxidation reactor I through the batching tank discharge pump;

[0022] (2) The jacketed heat medium of the jet loop oxidation reactor I provides auxiliary heat for the oxidation reaction, and the heat exchanger provides the main heat for the oxidation reaction. The mixed liquid from the batching tank enters the jet loop oxidation reactor I, and enters the heat exchanger through the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in oxygen. The gas-liquid mixture from the coupler enters the ejector. The gas and liquid from the ejector enter the jet loop oxidation reactor I together. The gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together.

[0023] (3) The heat medium in the jacket and heat exchanger of the jet loop oxidation reactor II heats the mixed liquid to the oxidation reaction temperature; the gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together, and enter the heat exchanger through the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in oxygen; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reactor II together; the gas and liquid overflowing from the jet loop oxidation reactor II enter the gas-liquid separator tank together.

[0024] (4) The unreacted oxygen in the oxidizing liquid in the gas-liquid separator is separated out by the condenser under the action of mechanical stirring; the oxidizing liquid with separated oxygen enters the jet loop sedimentation reactor I through the gas-liquid separator discharge pump.

[0025] (5) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor I heats the oxidizing liquid to the precipitation reaction temperature; the ferric sulfate solution from the discharge pump of the gas-liquid separator and the phosphoric acid from the phosphoric acid tank enter the jet loop sedimentation reactor I, and enter the heat exchanger through the power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry liquid from the ejector enters the jet loop sedimentation reactor I; the slurry liquid overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II;

[0026] (6) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor II heats the slurry to the sedimentation reaction temperature; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II, enters the heat exchanger via a power fluid pump, and after being heated by the heat exchanger, enters the coupler while simultaneously drawing in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet loop sedimentation reactor II; the slurry overflowing from the jet loop sedimentation reactor II enters the jet washing tank I;

[0027] (7) The heat medium in the jacket of the jet washing tank I heats the slurry to the washing temperature; the slurry overflowing from the jet loop sedimentation reactor II enters the jet washing tank I, and enters the coupler through the power fluid pump while simultaneously drawing in washing water. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet washing tank I; the slurry from the jet washing tank I enters the vacuum filter I through the discharge pump of the jet washing tank I.

[0028] (8) The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry of jet washing tank I enters vacuum filter I through the discharge pump of jet washing tank I, and the filter cake of vacuum filter I enters jet washing tank II through screw conveyor.

[0029] (9) The heat medium in the jacket of the jet washing tank II heats the slurry to the washing temperature; the filter cake from the vacuum filter I enters the jet washing tank II via the screw conveyor; the ferric phosphate slurry in the jet washing tank II enters the coupler via the power fluid pump and simultaneously draws in washing water; the mixed liquid from the coupler enters the ejector; the slurry from the ejector enters the jet washing tank II; the slurry from the jet washing tank II enters the vacuum filter II via the discharge pump of the jet washing tank II.

[0030] (10) The vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry of jet washing tank II enters vacuum filter II through the discharge pump of jet washing tank II, and the filter cake of vacuum filter II enters flash dryer through screw conveyor.

[0031] (11) The iron phosphate and the drying exhaust gas after flash drying are separated by a cyclone separator and a bag filter. The separated iron phosphate powder enters the iron phosphate silo for batteries.

[0032] The present invention also provides a method for preparing battery-grade iron phosphate based on the above-described apparatus, specifically comprising the following steps:

[0033] 1) The pickling solution and catalyst from the steel plant are added to the mixing tank and mixed evenly under the action of mechanical stirring. The mixture reaches the reaction temperature under the heating of the heat medium and enters the jet tube oxidation reactor through the discharge pump of the mixing tank.

[0034] 2) The mixed liquid in the jet tube oxidation reactor reaches the oxidation reaction temperature under the heating of the jacket heat medium. The mixed liquid from the feed tank discharge pump enters the symmetrical coupler of the jet tube oxidation reactor, and oxygen is drawn in at the same time. The gas-liquid mixture from the coupler enters the ejector, is impacted in the jet impact chamber and then enters the tubular reactor. The oxidation mixture from the tubular reactor enters the jet loop oxidation reactor I.

[0035] 3) The heat medium in the jacket and heat exchanger of jet loop oxidation reactor I heats the mixed liquid to the oxidation reaction temperature; the gas and liquid from the jet tube oxidation reactor enter jet loop oxidation reactor I together, and are then pumped into the heat exchanger by a gas-liquid mixing power fluid pump. After being heated by the heat exchanger, the mixture enters the coupler and simultaneously draws in oxygen; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter jet loop oxidation reactor I together; the gas and liquid overflowing from jet loop oxidation reactor I enter jet loop oxidation reactor II together.

[0036] 4) The heat medium in the jacket and heat exchanger of the jet loop oxidation reactor II heats the mixed liquid to the oxidation reaction temperature; the gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together, and enter the heat exchanger through the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in oxygen; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reactor II together; the gas and liquid overflowing from the jet loop oxidation reactor II enter the gas-liquid separator tank together.

[0037] 5) The unreacted oxygen in the oxidizing liquid in the gas-liquid separator is separated out by the condenser under the action of mechanical stirring; the oxidizing liquid with separated oxygen enters the jet loop sedimentation reactor I through the gas-liquid separator discharge pump.

[0038] 6) The heat medium in the jacket and heat exchanger of jet loop sedimentation reactor I heats the oxidizing liquid to the precipitation reaction temperature; the ferric sulfate solution from the discharge pump of the gas-liquid separator and the phosphoric acid from the phosphoric acid tank enter the jet loop sedimentation reactor I, and are then pumped into the heat exchanger. After being heated by the heat exchanger, they enter the coupler and simultaneously draw in ammonia from the ammonia tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet loop sedimentation reactor I; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II;

[0039] 7) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor II heats the slurry to the sedimentation reaction temperature; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II, is pumped into the heat exchanger, is heated by the heat exchanger, and then enters the coupler while simultaneously drawing in ammonia from the ammonia tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet loop sedimentation reactor II; the slurry overflowing from the jet loop sedimentation reactor II enters the jet washing tank I;

[0040] 8) The jacketed heat transfer medium of jet washing tank I heats the slurry to the washing temperature; the slurry overflowing from the jet loop sedimentation reactor II enters jet washing tank I, and is pumped into the coupler by a power fluid pump while simultaneously drawing in washing water. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters jet washing tank I; the slurry from jet washing tank I enters vacuum filter I via the jet washing tank I discharge pump.

[0041] 9) The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry of jet washing tank I enters vacuum filter I through the discharge pump of jet washing tank I, and the filter cake of vacuum filter I enters jet washing tank II through screw conveyor;

[0042] 10) The heat transfer medium in the jacket of jet washing tank II heats the slurry to the washing temperature; the filter cake from vacuum filter I enters jet washing tank II via a screw conveyor; the ferric phosphate slurry in jet washing tank II enters the coupler via a power fluid pump and simultaneously draws in washing water; the mixed liquid from the coupler enters the ejector; the slurry from the ejector enters jet washing tank II; the slurry from jet washing tank II enters vacuum filter II via the discharge pump of jet washing tank II.

[0043] 11) The vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry of jet washing tank II enters vacuum filter II through the discharge pump of jet washing tank II, and the filter cake of vacuum filter II enters flash dryer through screw conveyor.

[0044] 12) After being dried by the flash dryer, the iron phosphate powder and the drying exhaust gas are separated by a cyclone separator and a bag filter. The separated iron phosphate powder enters the iron phosphate silo for batteries.

[0045] Further, in device one: the molar ratio of FeSO4 to H2SO4 in the acidic solution of steelmaking flue dust in step (1) is 1:0.5, and the molar ratio of FeSO4 to Fe2(SO4)3 is 1:0.85; the temperature in the mixing tank is 80℃~90℃, the pressure is 0.15MPa~0.2MPa, the catalyst is 1.4%~1.6% (mass) of FeSO4, the mass concentration of FeSO4 is 8.5%~9%, and the residence time of the material is 0.5h~0.75h;

[0046] Device 2: In step 1), the molar ratio of FeSO4 to H2SO4 in the steel plant pickling solution is 1:0.5; the temperature in the mixing tank is 80℃~90℃, the pressure is 0.15MPa~0.2MPa, the catalyst is 0.4%~0.45% (mass) of the pickling solution, the mass concentration of FeSO4 is 30%~35%, and the residence time of the material is 0.5h~0.75h.

[0047] Furthermore, the process conditions for the oxidation reaction in the device are as follows:

[0048] Device 1:

[0049] In step (2), the temperature inside the jet loop oxidation reactor I is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa. The material outlet temperature from the heat exchanger is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa. The feed oxygen to FeSO4 (based on the initial amount added from the mixing tank) to the coupler is (0.2~0.25):1 (molar ratio), i.e., (4.5~5.6) Nm³. 3 1 kmol; residence time of the material is 1 h to 1.5 h;

[0050] In step (3), the temperature inside the jet loop oxidation reactor II is 80℃~90℃, and the pressure is 0.4MPa~0.45MPa. The material outlet temperature from the heat exchanger is 80℃~90℃, and the pressure is 0.4MPa~0.45MPa. The feed oxygen to FeSO4 ratio (based on the initial amount added from the mixing tank) to the coupler is (0.2~0.25):1 (molar ratio), i.e., (4.5~5.6) Nm³. 3 1 kmol; residence time of the material is 1.5 h to 2 h;

[0051] Device 2:

[0052] In step 2), the temperature inside the jet tube oxidation reactor is 80℃~90℃, and the pressure is 0.5MPa~0.6MPa; the feed oxygen to FeSO4 (based on the initial amount added from the mixing tank) to the coupler is (0.15~0.2):1 (molar ratio), i.e. (3.4~4.5) Nm³. 3 1 kmol;

[0053] In step 3), the temperature inside the jet loop oxidation reactor I is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa. The material outlet temperature from the heat exchanger is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa. The feed oxygen to FeSO4 (based on the initial amount added from the mixing tank) to the coupler is (0.15~0.2):1 (molar ratio), i.e., (3.4~4.5) Nm³. 3 1 kmol; residence time of the material is 1 h to 1.5 h;

[0054] In step 4), the temperature inside the jet loop oxidation reactor II is 80℃~90℃, and the pressure is 0.4MPa~0.45MPa. The material outlet temperature from the heat exchanger is 80℃~90℃, and the pressure is 0.4MPa~0.45MPa. The feed oxygen to FeSO4 ratio (based on the initial amount added from the mixing tank) to the coupler is (0.15~0.2):1 (molar ratio), i.e., (3.4~4.5) Nm³. 3 1 kmol; residence time of the material is 1.5 h to 2 h.

[0055] Furthermore, the oxygen separated by the condenser of the gas-liquid separator in step (4) or step (5) enters the coupler of jet loop oxidation reactor I and jet loop oxidation reactor II; the jacket of the gas-liquid separator maintains the temperature of the oxidizing liquid at 70℃~80℃, and the pressure inside the tank is atmospheric pressure; the residence time of the material is 0.5h~1h.

[0056] Furthermore, the process conditions for the precipitation reaction in the apparatus are as follows:

[0057] Device 1:

[0058] In step (5), the temperature inside the jet loop sedimentation reactor I is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃~80℃; the feed mass concentration of 30% phosphoric acid:FeSO4 (based on the initial amount added to the batching tank) is 2.8:1~2.9:1 (molar ratio); the feed mass concentration of 20% ammonia water:FeSO4 (based on the initial amount added to the batching tank) to the coupler is 4.6:1~4.8:1 (molar ratio); the material residence time is 1.5h~2h;

[0059] In step (6), the temperature inside the jet loop sedimentation reactor II is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃~80℃; the feed mass concentration of ammonia water with a mass concentration of 20% to FeSO4 (based on the initial amount added from the batching tank) is 4.6:1~4.8:1 (molar ratio); the residence time of the material is 1.5h~2h;

[0060] Device 2:

[0061] In step 6), the temperature inside the jet loop sedimentation reactor I is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃~80℃; the feed mass concentration of 30% phosphoric acid:FeSO4 (based on the initial amount added to the mixing tank) is 1.03:1~1.05:1 (molar ratio); the feed mass concentration of 20% ammonia water:FeSO4 (based on the initial amount added to the mixing tank) to the coupler is 1.8:1~1.9:1 (molar ratio); the material residence time is 1.5h~2h.

[0062] In step 7), the temperature inside the jet loop sedimentation reactor II is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃~80℃; the feed mass concentration of ammonia water to FeSO4 (based on the initial amount added from the mixing tank) is 1.8:1~1.9:1 (molar ratio) to the coupler; the material residence time is 1.5h~2h.

[0063] Furthermore, the washing process conditions in the device are as follows:

[0064] In step (7) or step (8), the temperature inside the jet washing tank I is 60℃~70℃ and the pressure is atmospheric pressure; the washing water in the washing water buffer tank of the coupler feed vacuum filter I is 5:1~6:1 (mass ratio) of steelmaking flue dust acid solution / pickling liquid (based on the initial amount added to the batching tank); the residence time of the material is 1.0h~1.5h;

[0065] In step (8) or step (9), the slurry from jet washing tank I enters vacuum filter I via the discharge pump of jet washing tank I. The mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of jet washing tank I. Then, the mother liquor enters the ammonium salt mother liquor tank for ammonium salt recovery. The mother liquor from jet washing tank II washes the filter cake. The washing water of the filter cake is collected in the washing water buffer tank of vacuum filter I and then enters jet washing tank I. The filter cake from vacuum filter I enters jet washing tank II via a screw conveyor. The temperature of vacuum filter I is room temperature and the pressure is 0.02MPa to 0.01MPa. The ratio of mother liquor in jet washing tank II to steelmaking flue dust acid solution / pickling solution (based on the initial amount added to the batching tank) is 5:1 to 6:1 (mass ratio). The wet basis moisture content of the filter cake is 35% to 40%.

[0066] In step (9) or step (10), the temperature inside the jet washing tank II is 60℃~70℃ and the pressure is atmospheric pressure; the washing water in the washing water buffer tank of the coupler feed vacuum filter II is 5:1~6:1 (mass ratio) of steelmaking flue dust acid solution / pickling liquid (based on the initial amount added to the batching tank); the residence time of the material is 1.0h~1.5h;

[0067] In step (10) or step (11), the slurry from jet washing tank II enters vacuum filter II via the discharge pump of jet washing tank II. The mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of vacuum filter II. The filter cake is washed with process water, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter II and then enters jet washing tank II. The filter cake from vacuum filter II enters flash dryer via screw conveyor. The temperature of vacuum filter II is room temperature, and the pressure is 0.02MPa to 0.01MPa. The ratio of process water to steelmaking flue dust acid solution / pickling liquid (based on the initial amount added to the batching tank) is 5:1 to 6:1 (mass ratio). The wet basis moisture content of the filter cake is 35% to 40%.

[0068] Further, in step (11) or step 12), the fan of the flash dryer provides power air to the flash dryer, and the air heater provides heat source for the flash dryer; the filter cake of vacuum filter II enters the flash dryer via a screw conveyor; the air enters the flash dryer after passing through the air heater, and the dried iron phosphate and the drying exhaust gas are separated by a cyclone separator and a bag filter to separate the iron phosphate powder and the drying exhaust gas. The separated drying exhaust gas is released into the atmosphere, and the separated iron phosphate powder enters the iron phosphate silo for batteries via a star feeder; the outlet air temperature of the flash dryer air heater is 255℃~260℃, and the outlet gas temperature of the flash dryer is 115℃~120℃; the standard air volume is 11.5~12 (air volume kg / wet material kg), and the wet basis moisture content of the outlet dried material is less than 0.5%.

[0069] The apparatus and method for preparing battery-grade iron phosphate based on a jet reactor according to the present invention have the following advantages compared with the prior art:

[0070] 1. Effective utilization of steelmaking fumes / steel plant pickling waste liquid, turning waste into treasure; reuse of washing water, recovery of ammonium salts, and effective utilization of resources;

[0071] 2. The use of a jet reactor can create a sufficient gas-liquid (solid) mixing zone, which effectively promotes heat transfer, mass transfer, and momentum transfer, thereby enhancing the reaction and improving the reaction rate and product yield.

[0072] 3. The iron phosphate (FePO4·2H2O) for batteries prepared using steelmaking flue dust conforms to the HG / T 4701-2014 standard. The present invention features a mature process, advanced equipment, continuous operation, high degree of automation, shortened reaction time, energy saving, improved production efficiency, and environmental friendliness. Attached Figure Description

[0073] Figure 1 This is a schematic diagram of an apparatus for preparing battery-grade iron phosphate based on a jet reactor, according to Embodiment 1 of the present invention.

[0074] Figure 2 This is a schematic diagram of an apparatus for preparing battery-grade iron phosphate based on a jet reactor, according to Embodiment 2 of the present invention.

[0075] Figure 3 This is a schematic diagram of the jet tube oxidation reactor structure in Embodiment 2 of the present invention;

[0076] Attached reference numerals: 1. Batching tank; 1-1. Mechanical stirrer; 1-2. Jacket; 1-3. Batching tank discharge pump; 2. Jet loop oxidation reactor I; 2-1. Coupler; 2-2. Ejector; 2-3. Jacket; 2-4. Gas-liquid mixing power fluid pump; 2-5. Heat exchanger; 2-6. Oxygen buffer tank; 3. Jet loop oxidation reactor II; 3-1. Coupler; 3-2. Ejector; 3-3. Jacket; 3-4. Gas-liquid mixing power fluid pump; 3-5. Heat exchanger; 4. Gas-liquid separator; 4-1. Mechanical stirrer; 4-2. Jacket; 4- 3. Gas-liquid separator discharge pump; 4-4. Condenser; 5. Jet loop sedimentation reactor I; 5-1. Coupler; 5-2. Ejector; 5-3. Jacket; 5-4. Power fluid pump; 5-5. Heat exchanger; 5-6. Phosphoric acid tank; 5-7. Ammonia tank; 6. Jet loop sedimentation reactor II; 6-1. Coupler; 6-2. Ejector; 6-3. Jacket; 6-4. Power fluid pump; 6-5. Heat exchanger; 7. Jet scrubbing tank I; 7-1. Coupler; 7-2. Ejector; 7-3. Jacket; 7-4. Power fluid pump; 7-5. Jet scrubbing tank. 8. Vacuum Filter I, 8-1. Vacuum Chamber, 8-2. Jet Washing Tank I Mother Liquor Buffer Tank, 8-3. Vacuum Filter I Washing Water Buffer Tank, 8-4. Vacuum Pump, 8-5. Ammonium Salt Mother Liquor Tank, 8-6. Screw Conveyor; 9. Jet Washing Tank II, 9-1. Coupler, 9-2. Ejector, 9-3. Jacket, 9-4. Power Fluid Pump, 9-5. Jet Washing Tank II Discharge Pump; 10. Vacuum Filter II, 10-1. Vacuum Chamber, 10-2. Jet Washing Tank II Mother Liquor Buffer Tank, 10-3. Vacuum Filter II Washing Water Buffer Tank 10-4. Vacuum pump; 10-5. Jet washing tank II mother liquor pump; 10-6. Washing water pump; 10-7. Screw conveyor; 11. Flash dryer; 11-1. Fan; 11-2. Air heater; 11-3. Cyclone separator; 11-4. Rotary feeder; 11-5. Bag filter; 11-6. Rotary feeder; 11-7. Battery iron phosphate silo; 12. Jet tubular oxidation reactor; 12-1. Coupler; 12-2. Ejector; 12-3. Jet impact chamber; 12-4. Tubular reactor; 12-5. Jacket. Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0078] Example 1

[0079] like Figure 1As shown, an apparatus for preparing battery-grade iron phosphate based on a jet reactor is disclosed. The apparatus comprises, in sequence, a mixing tank 1, a jet loop oxidation reactor I 2, a jet loop oxidation reactor II 3, a gas-liquid separation tank 4, a jet loop precipitation reactor I 5, a jet loop precipitation reactor II 6, a jet washing tank I 7, a vacuum filter I 8, a jet washing tank II 9, a vacuum filter II 10, and a flash dryer 11. All three jet loop oxidation reactors (I, II, I, II, II, and II), jet washing tanks I and II) are jet reactors. Each of these reactors utilizes an ejector for gas-liquid-solid mixing. The ejector includes a coupler and an injector, with the coupler having a motive fluid inlet and a gas / liquid inlet.

[0080] The batching tank 1 includes a mechanical stirrer 1-1, a jacket 1-2, and a batching tank discharge pump 1-3. The batching tank is used to mix the catalyst and the purified and prepared steelmaking flue gas acid solution evenly under the action of mechanical stirring. The mixture reaches the reaction temperature under the heating of the heat medium and enters the jet loop oxidation reactor I through the batching tank discharge pump.

[0081] The jet-loop oxidation reactor I2 includes a coupler 2-1, an ejector 2-2, a jacket 2-3, a gas-liquid mixing power fluid pump 2-4, and a heat exchanger 2-5. The jet-loop oxidation reactor I is connected to an oxygen buffer tank 2-6. The jet-loop oxidation reactor I is used for an oxidation reaction, specifically oxidizing ferrous sulfate (FeSO4) in the acid solution of steelmaking flue gas to ferric sulfate (Fe2(SO4)3). The jacket of the jet-loop oxidation reactor I provides auxiliary heat for the oxidation reaction, while the heat exchanger provides the main heat. The mixed liquid from the batching tank enters the jet-loop oxidation reactor I, is pumped into the heat exchanger via the gas-liquid mixing power fluid pump, and after being heated by the heat exchanger, enters the coupler while simultaneously drawing in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator. The gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet-loop oxidation reactor I together. The gas and liquid overflowing from the jet-loop oxidation reactor I enter the jet-loop oxidation reactor II together.

[0082] The jet-loop oxidation reactor II 3 includes a coupler 3-1, an ejector 3-2, a jacket 3-3, a gas-liquid mixing power fluid pump 3-4, and a heat exchanger 3-5; the jet-loop oxidation reactor II is also connected to an oxygen buffer tank 2-6; the jet-loop oxidation reactor II is used to carry out an oxidation reaction, that is, to oxidize ferrous sulfate (FeSO4) in the acid solution of steelmaking flue dust to ferric sulfate (Fe2(SO4)3); the jacket of the jet-loop oxidation reactor II provides auxiliary heat for the oxidation reaction, and the heat exchanger provides the main heat for the oxidation reaction. Heat; the gas and liquid overflowing from jet loop oxidation reactor I enter jet loop oxidation reactor II together, and are then pumped by a gas-liquid mixing power fluid pump into a heat exchanger. After being heated by the heat exchanger, they enter the coupler while simultaneously drawing in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator. The gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter jet loop oxidation reactor II together. The gas and liquid overflowing from jet loop oxidation reactor II enter the gas-liquid separator together.

[0083] The gas-liquid separator 4 includes a mechanical stirrer 4-1, a jacket 4-2, a gas-liquid separator discharge pump 4-3, and a condenser 4-4. The gas-liquid separator is used to separate unreacted oxygen from the oxidation liquid. Under the action of mechanical stirring, the unreacted oxygen in the oxidation liquid in the gas-liquid separator is separated out by the condenser. The oxygen separated by the condenser of the gas-liquid separator enters the coupler of the jet loop oxidation reactor I and the coupler of the jet loop oxidation reactor II. The oxidation liquid with separated oxygen enters the jet loop sedimentation reactor I through the gas-liquid separator discharge pump.

[0084] The jet-loop precipitation reactor I 5 includes a coupler 5-1, an ejector 5-2, a jacket 5-3, a power fluid pump 5-4, and a heat exchanger 5-5. The jet-loop precipitation reactor I is also connected to a phosphoric acid tank 5-6 and an ammonia tank 5-7. The jet-loop precipitation reactor I is used for the precipitation reaction of ferric sulfate solution, phosphoric acid, and ammonia to produce ferric phosphate. The jacket of the jet-loop precipitation reactor I provides auxiliary heat for the precipitation reaction, and the heat exchanger provides the main heat for the precipitation reaction. Ferric sulfate solution from the gas-liquid separator discharge pump and phosphoric acid from the phosphoric acid tank enter the jet-loop precipitation reactor I, are pumped into the heat exchanger, and after being heated by the heat exchanger, enter the coupler while simultaneously drawing in ammonia from the ammonia tank. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet-loop precipitation reactor I. The slurry overflowing from the jet-loop precipitation reactor I enters the jet-loop precipitation reactor II.

[0085] The jet-loop precipitation reactor II 6 includes a coupler 6-1, an ejector 6-2, a jacket 6-3, a power fluid pump 6-4, and a heat exchanger 6-5. The jet-loop precipitation reactor II is also connected to an ammonia tank 5-7. The jet-loop precipitation reactor II is used for the precipitation reaction of ferric sulfate solution, phosphoric acid, and ammonia to produce ferric phosphate. The jacket of the jet-loop precipitation reactor II provides auxiliary heat for the precipitation reaction, and the heat exchanger provides the main heat for the precipitation reaction. The slurry overflowing from the jet-loop precipitation reactor I enters the jet-loop precipitation reactor II, is pumped into the heat exchanger, heated by the heat exchanger, and then enters the coupler while simultaneously drawing in ammonia from the ammonia tank. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet-loop precipitation reactor II. The slurry overflowing from the jet-loop precipitation reactor II enters the jet washing tank I.

[0086] The jet washing tank I 7 includes a coupler 7-1, an ejector 7-2, a jacket 7-3, and a power fluid pump 7-4. The jet washing tank I is connected to the washing water buffer tank 8-3 of the vacuum filter I. The jet washing tank I is used to wash out ammonium phosphate and ammonium sulfate from the ferric phosphate slurry. The jacket of the jet washing tank I provides heat for washing. The slurry overflowing from the jet loop sedimentation reactor II enters the jet washing tank I, and is pumped into the coupler via the power fluid pump, simultaneously drawing in washing water from the washing water buffer tank of the vacuum filter I. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet washing tank I. The slurry from the jet washing tank I is then pumped into the vacuum filter I via the jet washing tank I discharge pump.

[0087] The vacuum filter I includes a vacuum chamber 8-1, and a vacuum pump 8-4 provides vacuum to the vacuum filter I. The vacuum filter I is connected to a jet washing tank I mother liquor buffer tank 8-2 for collecting mother liquor, and a vacuum filter I washing water buffer tank 8-3 for collecting washing water. The jet washing tank I mother liquor buffer tank 8-2 is connected to an ammonium salt mother liquor tank 8-5. The vacuum filter I is also connected to a jet washing tank II mother liquor buffer tank 10-2. The vacuum filter I is used for solid-liquid separation of the washed ferric phosphate slurry. The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry from jet washing tank I enters vacuum filter I via the discharge pump of jet washing tank I, and the mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of jet washing tank I, and then the mother liquor enters the ammonium salt mother liquor tank for ammonium salt recovery; the mother liquor from jet washing tank II washes the filter cake, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter I, and then enters jet washing tank I; the filter cake of vacuum filter I enters jet washing tank II via screw conveyor 8-6;

[0088] The jet washing tank II 9 includes a coupler 9-1, an ejector 9-2, a jacket 9-3, and a power fluid pump 9-4. The jet washing tank II is connected to the washing water buffer tank 10-3 of the vacuum filter II. The jet washing tank II is used to wash the ferric phosphate filter cake filtered by the vacuum filter I, that is, to further wash out ammonium phosphate and ammonium sulfate from the ferric phosphate slurry. The jacket of the jet washing tank II provides heat for washing. The filter cake from the vacuum filter I enters the jet washing tank II via a screw conveyor. The ferric phosphate slurry in the jet washing tank II enters the coupler via the power fluid pump, simultaneously drawing in washing water from the washing water buffer tank of the vacuum filter II. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet washing tank II. The slurry from the jet washing tank II enters the vacuum filter II via the jet washing tank II discharge pump 9-5.

[0089] The vacuum filter II 10 includes a vacuum chamber 10-1, and a vacuum pump 10-4 provides vacuum to the vacuum filter II. The vacuum filter II is connected to a jet washing tank II mother liquor buffer tank 10-2 for collecting mother liquor and a washing water buffer tank 10-3 for collecting washing water. The jet washing tank II mother liquor buffer tank 10-2 is connected to the vacuum filter I via a jet washing tank II mother liquor pump 10-5, and the vacuum filter II washing water buffer tank 10-3 is connected to the jet washing tank II via a washing water pump 10-6. Air filter II is used for solid-liquid separation of the washed ferric phosphate slurry; the vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry from jet washing tank II enters vacuum filter II via the discharge pump of jet washing tank II, and the mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of vacuum filter II; the filter cake is washed with process water, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter II and then enters jet washing tank II; the filter cake of vacuum filter II enters flash dryer via screw conveyor 10-7;

[0090] The flash dryer 11 includes a fan 11-1 and an air heater 11-2. The flash dryer, cyclone separator 11-3, and bag filter 11-5 are connected in sequence. The cyclone separator and bag filter are connected to the battery iron phosphate silo 11-7 via star feeders 11-4 and 11-6, respectively. The flash dryer is used to dry the iron phosphate filter cake separated by the vacuum filter II. The fan of the flash dryer provides power air, and the air heater provides heat. The filter cake from the vacuum filter II enters the flash dryer via a screw conveyor. Air enters the flash dryer after passing through the air heater. The dried iron phosphate and drying exhaust gas are separated by the cyclone separator and bag filter, separating the iron phosphate powder and drying exhaust gas. The separated drying exhaust gas is vented, and the separated iron phosphate powder enters the battery iron phosphate silo via the star feeder.

[0091] The method for preparing battery-grade iron phosphate based on the above-mentioned apparatus specifically includes the following steps:

[0092] (1) The purified and prepared steelmaking flue dust acid solution and catalyst are added to the batching tank. Under the action of mechanical stirring, the purified and prepared steelmaking flue dust acid solution and catalyst are mixed evenly. The mixture reaches the reaction temperature under the heating of the heat medium and enters the jet loop oxidation reactor I through the batching tank discharge pump. The purified and prepared steelmaking flue dust acid solution (FeSO4 to H2SO4 molar ratio of 1:0.5, FeSO4 to Fe2(SO4)3 molar ratio of 1:0.85) and catalyst are added to the batching tank. The temperature in the batching tank is 80℃~90℃, the pressure is 0.15MPa~0.2MPa, the catalyst is 1.4%~1.6% (mass) of FeSO4, the mass concentration of FeSO4 is 8.5%~9%, and the residence time of the material is 0.5h~0.75h.

[0093] (2) The jacketed heat transfer medium of the jet loop oxidation reactor I provides auxiliary heat for the oxidation reaction, while the heat exchanger provides the main heat for the oxidation reaction. The mixed liquid from the feed tank enters the jet loop oxidation reactor I, and is then pumped into the heat exchanger via a gas-liquid mixing power fluid pump. After being heated by the heat exchanger, it enters the coupler, simultaneously drawing in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator. The gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reaction together. Gas and liquid overflowing from jet loop oxidation reactor I enter jet loop oxidation reactor II together; wherein, the temperature inside jet loop oxidation reactor I is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa, and the material exiting the heat exchanger is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa; the feed oxygen to FeSO4 (based on the initial amount added to the mixing tank) to the coupler is (0.2~0.25):1 (molar ratio), i.e. (4.5~5.6) Nm³. 3 1 kmol; residence time of the material is 1 h to 1.5 h;

[0094] (3) The heat medium in the jacket and heat exchanger of the jet loop oxidation reactor II heats the mixed liquid to the oxidation reaction temperature; the gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together, and enter the heat exchanger through the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop together. Oxidation reactor II; the gas and liquid overflowing from jet loop oxidation reactor II enter the gas-liquid separator together; wherein, the temperature inside the jet loop oxidation reactor II is 80℃~90℃, and the pressure is 0.4MPa~0.45MPa; the material outlet temperature from the heat exchanger is 80℃~90℃, and the pressure is 0.4MPa~0.45MPa; the feed oxygen to FeSO4 (based on the initial amount added from the batching tank) to the coupler is (0.2~0.25):1 (molar ratio), i.e., (4.5~5.6) Nm³. 3 1 kmol; residence time of the material is 1.5 h to 2 h;

[0095] (4) The heat transfer medium in the jacket of the gas-liquid separator maintains the oxidizing liquid at a certain temperature; the unreacted oxygen in the oxidizing liquid in the gas-liquid separator is separated out by the condenser under the action of mechanical stirring; the oxygen separated by the condenser of the gas-liquid separator enters the coupler of jet loop oxidation reactor I and jet loop oxidation reactor II, and the oxidizing liquid with separated oxygen enters the jet loop sedimentation reactor I through the gas-liquid separator discharge pump; wherein, the temperature in the gas-liquid separator is 70℃~80℃, the pressure is atmospheric pressure, and the residence time of the material is 0.5h~1h;

[0096] (5) The heat medium in the jacket and heat exchanger of the jet-loop sedimentation reactor I heats the oxidizing liquid to the precipitation reaction temperature; the ferric sulfate solution from the discharge pump of the gas-liquid separator and the phosphoric acid from the phosphoric acid tank enter the jet-loop sedimentation reactor I, and are then pumped into the heat exchanger. After being heated by the heat exchanger, they enter the coupler and simultaneously draw in ammonia from the ammonia tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet-loop sedimentation reactor I; the slurry overflowing from the jet-loop sedimentation reactor I enters the jet-loop sedimentation reactor... Jet-loop sedimentation reactor II; wherein, the temperature inside the jet-loop sedimentation reactor I is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃~80℃; the feed mass concentration of 30% phosphoric acid:FeSO4 (based on the initial amount added to the batching tank) is 2.8:1~2.9:1 (molar ratio); the feed mass concentration of 20% ammonia water:FeSO4 (based on the initial amount added to the batching tank) to the coupler is 4.6:1~4.8:1 (molar ratio); the material residence time is 1.5h~2h;

[0097] (6) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor II heats the slurry to the sedimentation reaction temperature; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II, enters the heat exchanger via a power fluid pump, and after being heated by the heat exchanger, enters the coupler while simultaneously drawing in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry liquid from the ejector enters the jet loop sedimentation reactor II; the slurry liquid overflowing from the jet loop sedimentation reactor II enters the jet washing tank I; wherein, the temperature inside the jet loop sedimentation reactor II is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃~80℃; the feed mass concentration of the coupler is 20% ammonia water:FeSO4 (based on the initial amount added from the batching tank) at a molar ratio of 4.6:1~4.8:1; the material residence time is 1.5h~2h;

[0098] (7) The jet washing tank I is jacketed with a heat transfer medium to heat the slurry to the washing temperature; the slurry overflowing from the jet loop sedimentation reactor II enters the jet washing tank I, and is pumped into the coupler by a power fluid pump while simultaneously drawing in washing water from the washing water buffer tank of the vacuum filter I; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet washing tank I; the slurry from the jet washing tank I enters the vacuum filter I via the discharge pump of the jet washing tank I; wherein, the temperature inside the jet washing tank I is 60℃~70℃, and the pressure is atmospheric pressure; the washing water from the washing water buffer tank of the vacuum filter I fed into the coupler is 5:1~6:1 (mass ratio) of steelmaking flue gas acid solution (based on the initial amount added to the batching tank); the residence time of the material is 1.0h~1.5h;

[0099] (8) The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry from jet washing tank I enters vacuum filter I through the discharge pump of jet washing tank I, and the mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of jet washing tank I, and then the mother liquor enters the ammonium salt mother liquor tank for ammonium salt recovery; the mother liquor from jet washing tank II washes the filter cake, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter I, and then enters jet washing tank I; the filter cake of vacuum filter I enters jet washing tank II through a screw conveyor; wherein, the temperature of vacuum filter I is room temperature and the pressure is 0.02MPa~0.01MPa; the ratio of mother liquor to steelmaking flue gas acid solution (based on the initial amount added to the batching tank) of jet washing tank II is 5:1~6:1 (mass ratio); the wet basis wet content of the filter cake is 35%~40%;

[0100] (9) The heat transfer medium in the jacket of jet washing tank II heats the slurry to the washing temperature; the filter cake from vacuum filter I enters jet washing tank II via a screw conveyor; the ferric phosphate slurry in jet washing tank II enters the coupler via a power fluid pump and simultaneously draws in washing water from the washing water buffer tank of vacuum filter II; the mixed liquid from the coupler enters the ejector; the slurry from the ejector enters jet washing tank II; the slurry in jet washing tank II enters vacuum filter II via the discharge pump of jet washing tank II; wherein, the temperature inside jet washing tank II is 60℃~70℃, and the pressure is atmospheric pressure; the washing water in the washing water buffer tank of vacuum filter II fed by the coupler: steelmaking flue gas acid solution (based on the initial amount added by the batching tank) is 5:1~6:1 (mass ratio); the residence time of the material is 1.0h~1.5h;

[0101] (10) The vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry of jet washing tank II enters vacuum filter II through the discharge pump of jet washing tank II, and the mother liquor is separated through the vacuum chamber and enters the mother liquor buffer tank of vacuum filter II; the filter cake is washed with process water, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter II and then enters jet washing tank II; the filter cake of vacuum filter II enters flash dryer through screw conveyor; wherein, the temperature of vacuum filter II is room temperature, the pressure is 0.02MPa~0.01MPa; the ratio of process water to steelmaking flue gas acid solution (based on the initial amount added to the batching tank) is 5:1~6:1 (mass ratio); the wet basis moisture content of the filter cake is 35%~40%;

[0102] (11) The fan of the flash dryer provides power air to the flash dryer, and the air heater provides heat source for the flash dryer; the filter cake of vacuum filter II enters the flash dryer through the screw conveyor; the air enters the flash dryer after passing through the air heater, and the dried iron phosphate and the drying exhaust gas are separated by the cyclone separator and bag filter to separate the iron phosphate powder and the drying exhaust gas. The separated drying exhaust gas is released into the atmosphere, and the separated iron phosphate powder enters the iron phosphate silo for batteries through the star feeder; wherein, the outlet air temperature of the flash dryer air heater is 255℃~260℃, the outlet gas temperature of the flash dryer is 115℃~120℃; the standard air volume is 11.5~12 (air volume kg / wet material kg), and the wet basis moisture content of the outlet dried material is less than 0.5%.

[0103] Example 2

[0104] like Figure 2As shown, an apparatus for preparing battery-grade iron phosphate based on steel plant pickling waste liquid includes a batching tank 1, a jet tube oxidation reactor 12, a jet loop oxidation reactor I 2, a jet loop oxidation reactor II 3, a gas-liquid separation tank 4, a jet loop precipitation reactor I 5, a jet loop precipitation reactor II 6, a jet washing tank I 7, a vacuum filter I 8, a jet washing tank II 9, a vacuum filter II 10, and a flash dryer 11, connected in sequence.

[0105] The difference between this embodiment and Embodiment 1 is that a jet tube oxidation reactor 17 is further provided between the mixing tank and the jet loop oxidation reactor I; the jet tube oxidation reactor uses an ejector for gas-liquid-solid mixing; as... Figure 3 As shown, the jet-tube oxidation reactor includes a jet injector (including a coupler 12-1 and an ejector 12-2), a jet impact chamber 12-3, and a tubular reactor 12-4; the jet impact chamber has an ellipsoidal structure, and the tubular reactor has an arc-shaped structure; the jet injectors are symmetrically arranged at both ends of the jet impact chamber, and the jet impact chamber is connected to the inner cavity of the tubular reactor; the outer wall of the tubular oxidation reactor is provided with a jacket 12-5; the jacket is used to introduce a heat medium for heating; the jet-tube oxidation reactor is connected to an oxygen buffer tank 2-6. The jet tube oxidation reactor is used to carry out an oxidation reaction, that is, to oxidize ferrous sulfate (FeSO4) in the pickling solution to ferric sulfate (Fe2(SO4)3). The jacket of the jet tube oxidation reactor provides heat for the oxidation reaction. The mixed liquid from the feed tank discharge pump enters the symmetrical coupler of the jet tube oxidation reactor, and at the same time, oxygen from the oxygen buffer tank is drawn in. The gas-liquid mixture from the coupler enters the ejector, is impacted in the jet impact chamber, and then enters the tubular reactor. The oxidation mixture from the tubular reactor enters the jet loop oxidation reactor I.

[0106] The connection method and function of the remaining devices in this embodiment are the same as in Embodiment 1.

[0107] The method for preparing battery-grade iron phosphate based on the apparatus described in Example 2 differs from that in Example 1 in that:

[0108] A. The raw materials are different; the raw material is purified and prepared steel mill pickling solution (the molar ratio of FeSO4 to H2SO4 is 1:0.5).

[0109] B. After being discharged from the mixing tank, the mixture first enters the jet tube oxidation reactor for reaction and then enters the jet loop oxidation reactor I. Specifically, the mixture entering the jet tube oxidation reactor through the mixing tank discharge pump reaches the oxidation reaction temperature under the heating of the jacket heat medium. The mixture exiting the mixing tank discharge pump enters the symmetrical coupler of the jet tube oxidation reactor, while simultaneously drawing in oxygen from the oxygen buffer tank. The gas-liquid mixture exiting the coupler enters the ejector, collides in the jet impact chamber, and then enters the tubular reactor. The oxidation mixture exiting the tubular reactor enters the jet loop oxidation reactor I.

[0110] C. Different process parameters: The temperature inside the batching tank is 80℃~90℃, the pressure is 0.15MPa~0.2MPa, the catalyst is 0.4%~0.45% (mass) of the pickling solution, the mass concentration of FeSO4 is 30%~35%, and the residence time of the material is 0.5h~0.75h;

[0111] The temperature inside the jet-tube oxidation reactor is 80℃~90℃, and the pressure is 0.5MPa~0.6MPa; the feed oxygen to FeSO4 (based on the initial amount added from the mixing tank) to the coupler is (0.15~0.2):1 (molar ratio), i.e. (3.4~4.5) Nm³. 3 The temperature inside the jet loop oxidation reactor I is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa. The material outlet temperature from the heat exchanger is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa. The feed oxygen to FeSO4 ratio (based on the initial amount added from the mixing tank) to the coupler is (0.15~0.2):1 (molar ratio), i.e., (3.4~4.5) Nm³. 3 1 kmol; the residence time of the material is 1 h to 1.5 h; the temperature inside the jet loop oxidation reactor II is 80℃ to 90℃, and the pressure is 0.4 MPa to 0.45 MPa; the material outlet temperature from the heat exchanger is 80℃ to 90℃, and the pressure is 0.4 MPa to 0.45 MPa; the feed oxygen to FeSO4 (based on the initial amount added from the mixing tank) to the coupler is (0.15 to 0.2):1 (molar ratio), i.e., (3.4 to 4.5) Nm³. 3 1 kmol; residence time of the material is 1.5 h to 2 h;

[0112] The temperature inside the gas-liquid separator is 70℃~80℃, and the pressure is atmospheric pressure; the residence time of the material is 0.5h~1h; the temperature inside the jet loop sedimentation reactor I is 70℃~80℃, and the pressure is atmospheric pressure; the material outlet temperature from the heat exchanger is 70℃~80℃; the feed mass concentration of 30% phosphoric acid:FeSO4 (based on the initial amount added from the mixing tank) is 1.03:1~1.05:1 (molar ratio); the coupler feed mass concentration of 20% ammonia water:FeSO4 ( The molar ratio of ammonia water to FeSO4 (based on the initial amount added from the mixing tank) is 1.8:1 to 1.9:1; the residence time of the material is 1.5h to 2h; the temperature inside the jet loop sedimentation reactor II is 70℃ to 80℃, the pressure is atmospheric pressure, and the temperature of the material exiting the heat exchanger is 70℃ to 80℃; the feed concentration of the coupler is 20% ammonia water:FeSO4 (based on the initial amount added from the mixing tank) at a molar ratio of 1.8:1 to 1.9:1; the residence time of the material is 1.5h to 2h.

[0113] The temperature inside the jet washing tank I is 60℃~70℃, and the pressure is atmospheric pressure; the washing water to pickling solution ratio (based on the initial amount added from the mixing tank) in the washing water buffer tank of the coupler-feed vacuum filter I is 5:1~6:1 (mass ratio); the material residence time is 1.0h~1.5h; the temperature of the vacuum filter I is ambient temperature, and the pressure is 0.02MPa~0.01MPa; the mother liquor to pickling solution ratio (based on the initial amount added from the mixing tank) in the jet washing tank II is 5:1~6:1 (mass ratio); the wet basis moisture content of the filter cake is 35%~4%. 0%; the temperature inside the jet washing tank II is 60℃~70℃, and the pressure is atmospheric pressure; the washing water to pickling solution (based on the initial amount added to the mixing tank) ratio in the washing water buffer tank of the coupler feed vacuum filter II is 5:1~6:1 (mass ratio); the material residence time is 1.0h~1.5h; the temperature of the vacuum filter II is ambient temperature, and the pressure is 0.02MPa~0.01MPa; the process water to pickling solution (based on the initial amount added to the mixing tank) ratio is 5:1~6:1 (mass ratio); the wet basis moisture content of the filter cake is 35%~40%;

[0114] The outlet air temperature of the flash dryer air heater is 255℃~260℃, and the outlet gas temperature of the flash dryer is 115℃~120℃; the standard air volume is 11.5~12 (air volume kg / wet material kg), and the wet basis moisture content of the dried material at the outlet is less than 0.5%.

[0115] In embodiments 1 and 2 of this invention, a jet reactor is used for oxidation and precipitation reactions. In the jet reactor, the high-speed ejection of the motive fluid via the ejector creates a negative pressure zone at the gas (liquid) inlet of the coupler, causing the gas (liquid) to be drawn in. Within this negative pressure zone, the gas (liquid) rapidly expands and is broken into tiny bubbles (droplets) by the motive fluid, entering the mixing chamber. At this point, the gas (liquid) and liquid are thoroughly mixed in the mixing chamber and accelerated outwards due to energy exchange, reaching speeds approaching sonic velocity. The diffusion chamber of the ejector further maximizes the potential energy of the mixture, enhancing mass and heat transfer, and significantly improving heat, mass, and momentum transfer during the process. Its strong micro-mixing characteristics enable rapid chemical reactions, and the turbulent state rapidly reduces the mixing scale. The vortices of different scales and their folding and collision enhance the turbulence intensity and energy diffusion, prompting molecules to reach more efficient high-energy collisions during chemical reactions. This effectively improves the mixing and mass transfer effect within the reactor and increases the reaction rate. The jet reactor used in this invention can form a sufficient gas (liquid)-liquid mixing zone, effectively promoting heat transfer, mass transfer, and momentum transfer, thereby strengthening the reaction and increasing the reaction rate and product yield. The prepared iron phosphate (FePO4·2H2O) for batteries conforms to the HG / T 4701-2014 standard.

[0116] In this invention, the various devices and equipment are connected via corresponding pipelines, attached Figure 1 , 2 When pipelines intersect on the drawing but do not actually intersect, they should be drawn according to the principle of vertical breaks but horizontal breaks.

[0117] Example 3

[0118] The method for producing battery-grade iron phosphate based on the apparatus for preparing battery-grade iron phosphate using a jet reactor as described in Example 1 includes the following steps:

[0119] (1) 1788 kg / h of purified and prepared steelmaking flue gas acid solution (FeSO4 to H2SO4 molar ratio of 1:0.5, FeSO4 to Fe2(SO4)3 molar ratio of 1:0.85) and 2.432 kg / h of catalyst were added to the mixing tank. The purified and prepared steelmaking flue gas acid solution and catalyst were mixed evenly under the action of mechanical stirring. The mixture reached the reaction temperature under the heating of the heat medium and entered the jet loop oxidation reactor I through the discharge pump of the mixing tank. The temperature in the mixing tank was 80℃, the pressure was 0.15 MPa, the catalyst was 1.6% (mass) of FeSO4, the mass concentration of FeSO4 was 8.5%, and the residence time of the material was 0.75 h.

[0120] (2) The jacket of the jet loop oxidation reactor I provides auxiliary heat for the oxidation reaction, while the heat exchanger provides the main heat for the oxidation reaction. The mixed liquid from the batching tank enters the jet loop oxidation reactor I, and after being heated by the gas-liquid mixing power fluid pump, it enters the heat exchanger and then enters the coupler, simultaneously drawing in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator. The gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reactor I together. The gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together. The temperature inside the jet loop oxidation reactor I is 80℃, and the pressure is 0.45MPa. The material outlet temperature from the heat exchanger is 80℃, and the pressure is 0.45MPa. The feed oxygen to FeSO4 (based on the initial amount added from the batching tank) to the coupler is 0.25:1 (molar ratio), i.e., 5.6Nm³. 3 1 kmol, oxygen 5.6 Nm 3 / h; The residence time of the material is 1.5h;

[0121] (3) The heat medium in the jacket and heat exchanger of the jet loop oxidation reactor II heats the mixed liquid to the oxidation reaction temperature; the gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together, and enter the heat exchanger through the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reactor II together; the gas and liquid overflowing from the jet loop oxidation reactor II enter the gas-liquid separator together; the temperature inside the jet loop oxidation reactor II is 80℃ and the pressure is 0.4MPa, the material outlet temperature from the heat exchanger is 80℃ and the pressure is 0.4MPa; the feed oxygen to FeSO4 (based on the initial amount added from the batching tank) to the coupler is 0.25:1 (molar ratio), i.e., 5.6Nm 3 1 kmol, oxygen 5.6 Nm 3 / h; The residence time of the material is 2h;

[0122] (4) The jacketed heat medium of the gas-liquid separator maintains the oxidizing liquid at a certain temperature; the unreacted oxygen in the oxidizing liquid in the gas-liquid separator is separated out by the condenser under the action of mechanical stirring; the oxygen separated by the condenser of the gas-liquid separator enters the coupler of jet loop oxidation reactor I and jet loop oxidation reactor II, and the oxidizing liquid with separated oxygen enters the jet loop sedimentation reactor I through the gas-liquid separator discharge pump; the temperature in the gas-liquid separator is 70℃ and the pressure is atmospheric pressure; the residence time of the material is 1h;

[0123] (5) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor I heats the oxidizing liquid to the precipitation reaction temperature; the ferric sulfate solution from the discharge pump of the gas-liquid separator and the phosphoric acid from the phosphoric acid tank enter the jet loop sedimentation reactor I, and are then pumped into the heat exchanger. After being heated by the heat exchanger, they enter the coupler and simultaneously draw in ammonia from the ammonia tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet loop sedimentation reactor I; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop. Precipitation reactor II; the temperature inside the jet loop precipitation reactor I is 70℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃; the feed mass concentration of 30% phosphoric acid:FeSO4 (based on the initial amount added to the batching tank) is 2.9:1 (molar ratio), resulting in a 30% phosphoric acid flow rate of 947 kg / h; the coupler feed mass concentration of 20% ammonia water:FeSO4 (based on the initial amount added to the batching tank) is 4.8:1 (molar ratio), resulting in a 20% ammonia water flow rate of 840 kg / h; the material residence time is 2 hours;

[0124] (6) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor II heats the slurry to the sedimentation reaction temperature; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II, enters the heat exchanger via a power fluid pump, and after being heated by the heat exchanger, enters the coupler while simultaneously drawing in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry liquid from the ejector enters the jet loop sedimentation reactor II; the slurry liquid overflowing from the jet loop sedimentation reactor II enters the jet washing tank I; the temperature inside the jet loop sedimentation reactor II is 70℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃; the feed to the coupler is 20% ammonia water:FeSO4 (based on the initial amount added from the batching tank) at a molar ratio of 4.8:1, with a 20% ammonia water concentration of 840 kg / h; the material residence time is 2 h;

[0125] (7) The jacketed heat medium of jet washing tank I heats the slurry to the washing temperature; the slurry overflowing from the jet loop sedimentation reactor II enters jet washing tank I, and is pumped into the coupler by a power fluid pump while simultaneously drawing in washing water from the washing water buffer tank of vacuum filter I. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters jet washing tank I; the slurry from jet washing tank I enters vacuum filter I via the discharge pump of jet washing tank I; the temperature inside jet washing tank I is 60℃, and the pressure is atmospheric pressure; the washing water of the washing water buffer tank of vacuum filter I fed into the coupler is 5:1 (mass ratio) of steelmaking flue gas acid solution (based on the initial amount added to the batching tank), and the washing water of the washing water buffer tank of vacuum filter I fed into the coupler is 8940 kg / h; the residence time of the material is 1.5 h;

[0126] (8) The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry of jet washing tank I enters vacuum filter I through the discharge pump of jet washing tank I, and the mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of jet washing tank I, and then the mother liquor enters the ammonium salt mother liquor tank for ammonium salt recovery; the mother liquor from jet washing tank II washes the filter cake, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter I, and then enters jet washing tank I; the filter cake of vacuum filter I enters jet washing tank II through the screw conveyor; the temperature of vacuum filter I is room temperature and the pressure is 0.02MPa; the mother liquor of jet washing tank II: steelmaking flue gas acid solution (based on the initial amount added to the batching tank) is 5:1 (mass ratio), the mother liquor of jet washing tank II is 8940kg / h; the wet basis wet content of the filter cake is 40%;

[0127] (9) The heat medium in the jacket of the jet washing tank II heats the slurry to the washing temperature; the filter cake from the vacuum filter I enters the jet washing tank II via a screw conveyor; the ferric phosphate slurry in the jet washing tank II enters the coupler via a power fluid pump and simultaneously draws in washing water from the washing water buffer tank of the vacuum filter II; the mixed liquid from the coupler enters the ejector; the slurry from the ejector enters the jet washing tank II; the slurry from the jet washing tank II enters the vacuum filter II via the discharge pump of the jet washing tank II; the temperature inside the jet washing tank II is 60℃ and the pressure is atmospheric pressure; the washing water in the washing water buffer tank of the vacuum filter II fed by the coupler is 5:1 (mass ratio) of steelmaking flue gas acid solution (based on the initial amount added to the batching tank); the washing water in the washing water buffer tank of the vacuum filter II fed by the coupler is 8940 kg / h; the residence time of the material is 1.5 h;

[0128] (10) The vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry of jet washing tank II enters vacuum filter II through the discharge pump of jet washing tank II, and the mother liquor is separated through the vacuum chamber and enters the mother liquor buffer tank of vacuum filter II; the filter cake is washed with process water, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter II and then enters jet washing tank II; the filter cake of vacuum filter II enters flash dryer through screw conveyor; the temperature of vacuum filter II is room temperature and the pressure is 0.02MPa; the ratio of process water to steelmaking flue gas acid solution (based on the initial amount added in the batching tank) is 5:1 (mass ratio), the process water is 8940kg / h; the wet basis moisture content of the filter cake is 40%;

[0129] (11) The fan of the flash dryer provides power air to the flash dryer, and the air heater provides heat source for the flash dryer; the filter cake from vacuum filter II enters the flash dryer via a screw conveyor; air enters the flash dryer after passing through the air heater, and the dried ferric phosphate and drying exhaust gas are separated by a cyclone separator and a bag filter to separate the ferric phosphate powder and drying exhaust gas. The separated drying exhaust gas is released into the atmosphere, and the separated ferric phosphate powder enters the battery ferric phosphate silo via a star feeder. The outlet air temperature of the flash dryer air heater is 260℃, and the outlet gas temperature of the flash dryer is 120℃; the standard air volume is 12 (air volume kg / wet material kg), and the standard air volume is 10048 kg / h, which is 7761 Nm³. 3 1 / h; the wet basis content of the dried material at the outlet is less than 0.5%. 485 kg / h of iron phosphate (FePO4·2H2O) for battery use is produced.

[0130] Example 4

[0131] The method for producing battery-grade iron phosphate based on the apparatus for preparing battery-grade iron phosphate using a jet reactor as described in Example 1 includes the following steps:

[0132] (1) 1689 kg / h of purified and prepared steelmaking flue gas acid solution (FeSO4 to H2SO4 molar ratio of 1:0.5, FeSO4 to Fe2(SO4)3 molar ratio of 1:0.85) and 2.128 kg / h of catalyst were added to the mixing tank. The purified and prepared steelmaking flue gas acid solution and catalyst were mixed evenly under the action of mechanical stirring. The mixture reached the reaction temperature under the heating of the heat medium and entered the jet loop oxidation reactor I through the discharge pump of the mixing tank. The temperature in the mixing tank was 90℃, the pressure was 0.2 MPa, the catalyst was 1.4% (mass) of FeSO4, the mass concentration of FeSO4 was 9%, and the residence time of the material was 0.5 h.

[0133] (2) The jacket of jet loop oxidation reactor I provides auxiliary heat for the oxidation reaction, and the heat exchanger provides the main heat for the oxidation reaction. The mixed liquid from the batching tank enters jet loop oxidation reactor I, and after being heated by the gas-liquid mixing power fluid pump, it enters the heat exchanger and then enters the coupler, simultaneously drawing in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator. The gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter jet loop oxidation reactor I together. The gas and liquid overflowing from jet loop oxidation reactor I enter jet loop oxidation reactor II together. The temperature inside jet loop oxidation reactor I is 90℃ and the pressure is 0.5MPa. The material outlet temperature from the heat exchanger is 90℃ and the pressure is 0.5MPa. The feed oxygen to FeSO4 (based on the initial amount added from the batching tank) to the coupler is 0.2:1 (molar ratio), i.e., 4.5Nm. 3 1 kmol, oxygen 4.5 Nm 3 / h; The residence time of the material is 1h;

[0134] (3) The heat medium in the jacket and heat exchanger of the jet loop oxidation reactor II heats the mixed liquid to the oxidation reaction temperature; the gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together, and enter the heat exchanger through the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reactor II together; the gas and liquid overflowing from the jet loop oxidation reactor II enter the gas-liquid separator together; the temperature inside the jet loop oxidation reactor II is 90℃ and the pressure is 0.45MPa, the material outlet temperature from the heat exchanger is 90℃ and the pressure is 0.45MPa; the feed oxygen to FeSO4 (based on the initial amount added from the batching tank) to the coupler is 0.2:1 (molar ratio), i.e., 4.5Nm 3 1 kmol, oxygen 4.5 Nm 3 / h; The residence time of the material is 1.5h;

[0135] (4) The jacketed heat medium of the gas-liquid separator maintains the oxidizing liquid at a certain temperature; the unreacted oxygen in the oxidizing liquid in the gas-liquid separator is separated out by the condenser under the action of mechanical stirring; the oxygen separated by the condenser of the gas-liquid separator enters the coupler of jet loop oxidation reactor I and jet loop oxidation reactor II, and the oxidizing liquid with separated oxygen enters the jet loop sedimentation reactor I through the gas-liquid separator discharge pump; the temperature in the gas-liquid separator is 80℃ and the pressure is atmospheric pressure; the residence time of the material is 0.5h;

[0136] (5) The heat medium in the jacket and heat exchanger of the jet-loop sedimentation reactor I heats the oxidizing liquid to the precipitation reaction temperature; the ferric sulfate solution from the discharge pump of the gas-liquid separator and the phosphoric acid from the phosphoric acid tank enter the jet-loop sedimentation reactor I, and are then pumped into the heat exchanger. After being heated by the heat exchanger, they enter the coupler and simultaneously draw in ammonia from the ammonia tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet-loop sedimentation reactor I; the slurry overflowing from the jet-loop sedimentation reactor I enters the jet-loop sedimentation reactor... Precipitation reactor II; the temperature inside the jet loop precipitation reactor I is 80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 80℃; the feed mass concentration of 30% phosphoric acid:FeSO4 (based on the initial amount added to the mixing tank) is 2.8:1 (molar ratio), resulting in a 30% phosphoric acid flow rate of 915 kg / h; the coupler feed mass concentration of 20% ammonia water:FeSO4 (based on the initial amount added to the mixing tank) is 4.6:1 (molar ratio), resulting in a 20% ammonia water flow rate of 805 kg / h; the material residence time is 1.5 h;

[0137] (6) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor II heats the slurry to the sedimentation reaction temperature; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II, enters the heat exchanger via a power fluid pump, and after being heated by the heat exchanger, enters the coupler while simultaneously drawing in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry liquid from the ejector enters the jet loop sedimentation reactor II; the slurry liquid overflowing from the jet loop sedimentation reactor II enters the jet washing tank I; the temperature inside the jet loop sedimentation reactor II is 80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 80℃; the feed mass concentration of ammonia water:FeSO4 (based on the initial amount added from the batching tank) to the coupler is 4.6:1 (molar ratio), and the mass concentration of 20% ammonia water is 805 kg / h; the residence time of the material is 1.5 h;

[0138] (7) The heat transfer medium in the jacket of the jet washing tank I heats the slurry to the washing temperature; the slurry overflowing from the jet loop sedimentation reactor II enters the jet washing tank I, and is pumped into the coupler by a power fluid pump while simultaneously drawing in washing water from the washing water buffer tank of the vacuum filter I. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet washing tank I; the slurry from the jet washing tank I enters the vacuum filter I via the discharge pump of the jet washing tank I; the temperature inside the jet washing tank I is 70℃, and the pressure is atmospheric pressure; the washing water in the washing water buffer tank of the vacuum filter I fed by the coupler is 6:1 (mass ratio) of steelmaking flue gas acid solution (based on the initial amount added to the batching tank), and the washing water in the washing water buffer tank of the vacuum filter I fed by the coupler is 10134 kg / h; the residence time of the material is 1.0 h;

[0139] (8) The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry of jet washing tank I enters vacuum filter I through the discharge pump of jet washing tank I, and the mother liquor is separated through the vacuum chamber and enters the mother liquor buffer tank of jet washing tank I, and then the mother liquor enters the ammonium salt mother liquor tank for ammonium salt recovery; the mother liquor from jet washing tank II washes the filter cake, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter I, and then enters jet washing tank I; the filter cake of vacuum filter I enters jet washing tank II through the screw conveyor; the temperature of vacuum filter I is room temperature and the pressure is 0.01MPa; the mother liquor of jet washing tank II: steelmaking flue gas acid solution (based on the initial amount added to the batching tank) is 6:1 (mass ratio), the mother liquor of jet washing tank II is 10134kg / h; the wet basis wet content of the filter cake is 35%;

[0140] (9) The heat medium in the jacket of the jet washing tank II heats the slurry to the washing temperature; the filter cake from the vacuum filter I enters the jet washing tank II via a screw conveyor; the ferric phosphate slurry in the jet washing tank II enters the coupler via a power fluid pump and simultaneously draws in washing water from the washing water buffer tank of the vacuum filter II; the mixed liquid from the coupler enters the ejector; the slurry from the ejector enters the jet washing tank II; the slurry from the jet washing tank II enters the vacuum filter II via the discharge pump of the jet washing tank II; the temperature inside the jet washing tank II is 70℃ and the pressure is atmospheric pressure; the washing water in the washing water buffer tank of the vacuum filter II fed by the coupler is 6:1 (mass ratio) of steelmaking flue gas acid solution (based on the initial amount added to the batching tank); the washing water in the washing water buffer tank of the vacuum filter II fed by the coupler is 10134 kg / h; the residence time of the material is 1.0 h;

[0141] (10) The vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry of jet washing tank II enters vacuum filter II through the discharge pump of jet washing tank II, and the mother liquor is separated through the vacuum chamber and enters the mother liquor buffer tank of vacuum filter II; the filter cake is washed with process water, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter II and then enters jet washing tank II; the filter cake of vacuum filter II enters flash dryer through screw conveyor; the temperature of vacuum filter II is room temperature and the pressure is 0.01MPa; the ratio of process water to steelmaking flue gas acid solution (based on the initial amount added to the batching tank) is 6:1 (mass ratio), the process water is 10134kg / h; the wet basis moisture content of the filter cake is 35%;

[0142] (11) The fan of the flash dryer provides power to the flash dryer, and the air heater provides heat to the flash dryer; the filter cake from vacuum filter II enters the flash dryer via a screw conveyor; air enters the flash dryer after passing through the air heater, and the dried ferric phosphate and drying exhaust gas are separated by a cyclone separator and a bag filter to separate the ferric phosphate powder and drying exhaust gas. The separated drying exhaust gas is released into the atmosphere, and the separated ferric phosphate powder enters the battery ferric phosphate silo via a star feeder. The outlet air temperature of the flash dryer air heater is 255℃, and the outlet gas temperature of the flash dryer is 115℃; the standard air volume is 11.5 (air volume kg / wet material kg), and the standard air volume is 8888 kg / h, which is 6865 Nm³. 3 1 / h; the wet basis content of the dried material at the outlet is less than 0.5%. 486 kg / h of iron phosphate (FePO4·2H2O) for battery use is produced.

[0143] Example 5

[0144] The method for producing battery-grade iron phosphate based on the apparatus for preparing battery-grade iron phosphate using a jet reactor as described in Example 2 includes the following steps:

[0145] 1) 507 kg / h of purified and prepared steel plant pickling solution (FeSO4 to H2SO4 molar ratio of 1:0.5) and 2.282 kg / h of catalyst are added to the mixing tank. Under mechanical stirring, the purified and prepared steel plant pickling solution and catalyst are mixed evenly. The mixture is heated to the reaction temperature by a heat transfer medium and then enters the jet tube oxidation reactor through the discharge pump of the mixing tank. The temperature in the mixing tank is 80℃, the pressure is 0.15 MPa, the catalyst is 0.45% (mass) of the pickling solution, the mass concentration of FeSO4 is 30%, and the residence time of the material is 0.75 h.

[0146] 2) The mixed liquid in the jet tube oxidation reactor reaches the oxidation reaction temperature under the heating of the jacketed heat medium. The mixed liquid from the feed tank discharge pump enters the symmetrical coupler of the jet tube oxidation reactor, while simultaneously drawing in oxygen from the oxygen buffer tank. The gas-liquid mixture from the coupler enters the ejector, collides in the jet impact chamber, and then enters the tubular reactor. The oxidation mixture from the tubular reactor enters the jet loop oxidation reactor I. The temperature inside the jet tube oxidation reactor is 80℃, and the pressure is 0.5MPa. The feed oxygen to FeSO4 (based on the initial amount added from the feed tank) to the coupler is 0.2:1 (molar ratio), i.e., 4.5Nm. 3 1 kmol; oxygen (mass content greater than 99%) feed 4.5 Nm 3 / h;

[0147] 3) The heat medium in the jacket and heat exchanger of jet loop oxidation reactor I heats the mixed liquid to the oxidation reaction temperature. Gas and liquid from the jet tube oxidation reactor enter jet loop oxidation reactor I together, and are then pumped into the heat exchanger via a gas-liquid mixing power fluid pump. After being heated by the heat exchanger, they enter the coupler, simultaneously drawing in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator. The gas-liquid mixture from the coupler enters the ejector, and gas and liquid from the ejector enter jet loop oxidation reactor I together. Gas and liquid overflowing from jet loop oxidation reactor I enter jet loop oxidation reactor II together. The temperature inside jet loop oxidation reactor I is 80℃, and the pressure is 0.45MPa. The material exiting the heat exchanger is at 80℃ and the pressure is 0.45MPa. The feed oxygen to FeSO4 (based on the initial amount added from the mixing tank) to the coupler is 0.2:1 (molar ratio), i.e., 4.5 Nm³. 3 1 kmol; oxygen (mass content greater than 99%) feed 4.5 Nm 3 / h; The residence time of the material is 1.5h;

[0148] 4) The heat medium in the jacket and heat exchanger of the jet loop oxidation reactor II heats the mixed liquid to the oxidation reaction temperature; the gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together, and are then pumped into the heat exchanger by a gas-liquid mixing power fluid pump. After being heated by the heat exchanger, the mixture enters the coupler, simultaneously drawing in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reactor II together; the gas and liquid overflowing from the jet loop oxidation reactor II enter the gas-liquid separator together; the temperature inside the jet loop oxidation reactor II is 80℃, and the pressure is 0.4MPa; the material outlet temperature from the heat exchanger is 80℃, and the pressure is 0.4MPa; the feed oxygen to FeSO4 (based on the initial amount added from the mixing tank) to the coupler is 0.2:1 (molar ratio), i.e., 4.5Nm³. 3 1 kmol; oxygen (mass content greater than 99%) feed 4.5 Nm 3 / h; The residence time of the material is 2h;

[0149] 5) The jacketed heat transfer medium in the gas-liquid separator maintains the oxidizing liquid at a certain temperature; under the action of mechanical stirring, the unreacted oxygen in the oxidizing liquid in the gas-liquid separator is separated out by the condenser; the oxygen separated by the condenser of the gas-liquid separator enters the coupler of jet loop oxidation reactor I and jet loop oxidation reactor II, and the oxidizing liquid with separated oxygen enters the jet loop sedimentation reactor I through the gas-liquid separator discharge pump; the temperature in the gas-liquid separator is 70℃, the pressure is atmospheric pressure, and the residence time of the material is 1 hour;

[0150] 6) The heat medium in the jacket and heat exchanger of jet loop sedimentation reactor I heats the oxidizing liquid to the precipitation reaction temperature; the ferric sulfate solution from the gas-liquid separator discharge pump and the phosphoric acid from the phosphoric acid tank enter jet loop sedimentation reactor I, and are then pumped into the heat exchanger. After being heated by the heat exchanger, they enter the coupler and simultaneously draw in ammonia from the ammonia tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters jet loop sedimentation reactor I; the slurry overflowing from jet loop sedimentation reactor I enters jet loop sedimentation reactor II. The temperature inside the jet loop sedimentation reactor I is 70℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃; the feed mass concentration of 30% phosphoric acid:FeSO4 (based on the initial amount added to the mixing tank) is 1.03:1 (molar ratio); the feed phosphoric acid (mass concentration 30%) is 337 kg / h; the coupler feed mass concentration of 20% ammonia water:FeSO4 (based on the initial amount added to the mixing tank) is 1.9:1 (molar ratio); the feed ammonia water (mass concentration 20%) is 332.5 kg / h; the material residence time is 2 h;

[0151] 7) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor II heats the slurry to the sedimentation reaction temperature; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II, is pumped into the heat exchanger, and after being heated by the heat exchanger, enters the coupler while simultaneously drawing in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry liquid from the ejector enters the jet loop sedimentation reactor II; the slurry liquid overflowing from the jet loop sedimentation reactor II enters the jet washing tank I; the temperature inside the jet loop sedimentation reactor II is 70℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃; the feed to the coupler is 20% ammonia water:FeSO4 (based on the initial amount added from the batching tank) at a molar ratio of 1.9:1; the feed ammonia water (20% mass concentration) is 332.5 kg / h; the material residence time is 2 h;

[0152] 8) The jacketed heat transfer medium in jet washing tank I heats the slurry to the washing temperature; the slurry overflowing from the jet loop sedimentation reactor II enters jet washing tank I, and is pumped into the coupler by a power fluid pump while simultaneously drawing in washing water from the washing water buffer tank of vacuum filter I; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters jet washing tank I; the slurry from jet washing tank I enters vacuum filter I via the discharge pump of jet washing tank I; the temperature inside jet washing tank I is 60℃, and the pressure is atmospheric pressure; the washing water to pickling solution (based on the initial amount added from the batching tank) of the washing water buffer tank of vacuum filter I fed by the coupler is 6:1 (mass ratio), and the washing water flow rate of the washing water buffer tank of vacuum filter I is 3042 kg / h; the residence time of the material is 1.5 h;

[0153] 9) The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry from jet washing tank I enters vacuum filter I via the discharge pump of jet washing tank I, and the mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of jet washing tank I, and then the mother liquor enters the ammonium salt mother liquor tank for ammonium salt recovery; the mother liquor from jet washing tank II washes the filter cake, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter I, and then enters jet washing tank I; the filter cake from vacuum filter I enters jet washing tank II via a screw conveyor; the temperature of vacuum filter I is room temperature and the pressure is 0.01 MPa; the mother liquor to pickling solution (based on the initial amount added to the batching tank) of jet washing tank II is 5:1 (mass ratio), and the feed rate of mother liquor to jet washing tank II is 2535 kg / h; the wet basis moisture content of the filter cake is 35%;

[0154] 10) The jet washing tank II heats the slurry to the washing temperature using a jacketed heat transfer medium; the filter cake from vacuum filter I enters jet washing tank II via a screw conveyor; the ferric phosphate slurry from jet washing tank II enters the coupler via a power fluid pump, simultaneously drawing in washing water from the washing water buffer tank of vacuum filter II; the mixed liquid from the coupler enters the ejector; the slurry from the ejector enters jet washing tank II; the slurry from jet washing tank II enters vacuum filter II via the jet washing tank II discharge pump; the temperature inside jet washing tank II is 60℃, and the pressure is atmospheric pressure; the washing water to pickling solution (based on the initial amount added from the batching tank) feeds into the washing water buffer tank of vacuum filter II at a ratio of 6:1 (mass ratio); the washing water flow rate to the washing water buffer tank of vacuum filter II is 3042 kg / h; the material residence time is 1.5 h;

[0155] 11) The vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry from jet washing tank II enters vacuum filter II via the discharge pump of jet washing tank II, and the mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of vacuum filter II; the filter cake is washed with process water, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter II and then enters jet washing tank II; the filter cake of vacuum filter II enters flash dryer via screw conveyor; the temperature of vacuum filter II is room temperature, and the pressure is 0.01 MPa; the ratio of process water to pickling solution (based on the initial amount added to the batching tank) is 5:1 (mass ratio), the feed process water is 2535 kg / h; the wet basis moisture content of the filter cake is 35%;

[0156] 12) The fan of the flash dryer provides power to the flash dryer, and the air heater provides heat to the flash dryer; the filter cake from vacuum filter II enters the flash dryer via a screw conveyor; air enters the flash dryer after passing through the air heater; the dried ferric phosphate and drying exhaust gas are separated by a cyclone separator and a bag filter to separate the ferric phosphate powder and drying exhaust gas; the separated drying exhaust gas is vented, and the separated ferric phosphate powder enters the battery ferric phosphate silo via a star feeder; the outlet air temperature of the flash dryer air heater is 255℃, and the outlet gas temperature of the flash dryer is 115℃; the standard air volume is 11.5 (air volume kg / wet material kg), and the standard air volume is 3292 kg / h, i.e., 2543 Nm³. 3 1 / h; the moisture content of the dried material at the outlet is less than 0.5%; the output of iron phosphate (FePO4·2H2O) for batteries is 181 kg / h.

[0157] Example 6

[0158] The method for producing battery-grade iron phosphate based on the apparatus for preparing battery-grade iron phosphate using a jet reactor as described in Example 2 includes the following steps:

[0159] 1) 434 kg / h of purified and prepared steel plant pickling solution (FeSO4 to H2SO4 molar ratio of 1:0.5) and 1.736 kg / h of catalyst are added to the mixing tank. Under mechanical stirring, the purified and prepared steel plant pickling solution and catalyst are mixed evenly. The mixture is heated to the reaction temperature by a heat transfer medium and then enters the jet tube oxidation reactor through the discharge pump of the mixing tank. The temperature in the mixing tank is 90℃, the pressure is 0.2 MPa, the catalyst is 0.4% (mass) of the pickling solution, the mass concentration of FeSO4 is 35%, and the residence time of the material is 0.5 h.

[0160] 2) The mixed liquid in the jet tube oxidation reactor reaches the oxidation reaction temperature under the heating of the jacketed heat medium. The mixed liquid from the feed tank discharge pump enters the symmetrical coupler of the jet tube oxidation reactor, while simultaneously drawing in oxygen from the oxygen buffer tank. The gas-liquid mixture from the coupler enters the ejector, collides in the jet impact chamber, and then enters the tubular reactor. The oxidation mixture from the tubular reactor enters the jet loop oxidation reactor I. The temperature inside the jet tube oxidation reactor is 90℃, and the pressure is 0.6MPa. The feed oxygen to FeSO4 (based on the initial amount added from the feed tank) to the coupler is 0.15:1 (molar ratio), i.e., 3.4Nm³. 3 1 kmol; oxygen (mass content greater than 99%) feed 3.4 Nm 3 / h;

[0161] 3) The heat medium in the jacket and heat exchanger of jet loop oxidation reactor I heats the mixed liquid to the oxidation reaction temperature. Gas and liquid from the jet tube oxidation reactor enter jet loop oxidation reactor I together, and are then pumped into the heat exchanger via a gas-liquid mixing power fluid pump. After being heated by the heat exchanger, they enter the coupler, simultaneously drawing in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator. The gas-liquid mixture from the coupler enters the ejector, and gas and liquid from the ejector enter jet loop oxidation reactor I together. Gas and liquid overflowing from jet loop oxidation reactor I enter jet loop oxidation reactor II together. The temperature inside jet loop oxidation reactor I is 90℃, and the pressure is 0.5MPa. The material exiting the heat exchanger is also at 90℃ and 0.5MPa. The feed oxygen to FeSO4 (based on the initial amount added from the mixing tank) to the coupler is 0.15:1 (molar ratio), i.e., 3.4 Nm³. 3 1 kmol; oxygen (mass content greater than 99%) feed 3.4 Nm 3 / h; The residence time of the material is 1h;

[0162] 4) The heat medium in the jacket and heat exchanger of the jet loop oxidation reactor II heats the mixed liquid to the oxidation reaction temperature; the gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together, and are then pumped into the heat exchanger by a gas-liquid mixing power fluid pump. After being heated by the heat exchanger, the mixture enters the coupler, simultaneously drawing in oxygen from the oxygen buffer tank and oxygen separated from the condenser of the gas-liquid separator; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reactor II together; the gas and liquid overflowing from the jet loop oxidation reactor II enter the gas-liquid separator together; the temperature inside the jet loop oxidation reactor II is 90℃, and the pressure is 0.45MPa; the material outlet temperature from the heat exchanger is 90℃, and the pressure is 0.45MPa; the feed oxygen to FeSO4 (based on the initial amount added from the mixing tank) to the coupler is 0.15:1 (molar ratio), i.e., 3.4Nm³. 3 1 kmol; oxygen (mass content greater than 99%) feed 3.4 Nm 3 / h; The residence time of the material is 1.5h;

[0163] 5) The jacketed heat transfer medium in the gas-liquid separator maintains the oxidizing liquid at a certain temperature; under the action of mechanical stirring, the unreacted oxygen in the oxidizing liquid in the gas-liquid separator is separated out by the condenser; the oxygen separated by the condenser of the gas-liquid separator enters the coupler of jet loop oxidation reactor I and jet loop oxidation reactor II, and the oxidizing liquid with separated oxygen enters the jet loop sedimentation reactor I via the gas-liquid separator discharge pump; the temperature in the gas-liquid separator is 80℃, the pressure is atmospheric pressure, and the residence time of the material is 0.5h;

[0164] 6) The heat medium in the jacket and heat exchanger of jet loop sedimentation reactor I heats the oxidizing liquid to the precipitation reaction temperature; the ferric sulfate solution from the gas-liquid separator discharge pump and the phosphoric acid from the phosphoric acid tank enter jet loop sedimentation reactor I, and are then pumped into the heat exchanger. After being heated by the heat exchanger, they enter the coupler and simultaneously draw in ammonia from the ammonia tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters jet loop sedimentation reactor I; the slurry overflowing from jet loop sedimentation reactor I enters jet loop sedimentation reactor II. The temperature inside the jet loop sedimentation reactor I is 80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 80℃; the feed mass concentration of 30% phosphoric acid:FeSO4 (based on the initial amount added to the mixing tank) is 1.05:1 (molar ratio); the feed phosphoric acid (mass concentration 30%) is 343 kg / h; the coupler feed mass concentration of 20% ammonia water:FeSO4 (based on the initial amount added to the mixing tank) is 1.8:1 (molar ratio); the feed ammonia water (mass concentration 20%) is 315 kg / h; the material residence time is 1.5 h;

[0165] 7) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor II heats the slurry to the sedimentation reaction temperature; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II, is pumped into the heat exchanger, and after being heated by the heat exchanger, enters the coupler while simultaneously drawing in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry liquid from the ejector enters the jet loop sedimentation reactor II; the slurry liquid overflowing from the jet loop sedimentation reactor II enters the jet washing tank I; the temperature inside the jet loop sedimentation reactor II is 80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 80℃; the feed to the coupler is 20% ammonia water:FeSO4 (based on the initial amount added from the batching tank) at a molar ratio of 1.8:1; the feed ammonia water (20% mass concentration) is 315 kg / h; the material residence time is 1.5 h;

[0166] 8) The jacketed heat transfer medium in jet washing tank I heats the slurry to the washing temperature; the slurry overflowing from the jet loop sedimentation reactor II enters jet washing tank I, and is pumped into the coupler by a power fluid pump while simultaneously drawing in washing water from the washing water buffer tank of vacuum filter I. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters jet washing tank I; the slurry from jet washing tank I enters vacuum filter I via the discharge pump of jet washing tank I; the temperature inside jet washing tank I is 70℃, and the pressure is atmospheric pressure; the washing water to pickling solution (based on the initial amount added from the batching tank) of the washing water buffer tank of vacuum filter I fed by the coupler is 5:1 (mass ratio), and the washing water flow rate of the washing water buffer tank of vacuum filter I is 2170 kg / h; the residence time of the material is 1.0 h;

[0167] 9) The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry from jet washing tank I enters vacuum filter I via the discharge pump of jet washing tank I, and the mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of jet washing tank I, and then the mother liquor enters the ammonium salt mother liquor tank for ammonium salt recovery; the mother liquor from jet washing tank II washes the filter cake, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter I, and then enters jet washing tank I; the filter cake from vacuum filter I enters jet washing tank II via a screw conveyor; the temperature of vacuum filter I is room temperature and the pressure is 0.02MPa; the mother liquor to pickling solution (based on the initial amount added to the batching tank) of jet washing tank II is 6:1 (mass ratio), and the feed rate of mother liquor to jet washing tank II is 2604kg / h; the wet basis moisture content of the filter cake is 40%;

[0168] 10) The jet washing tank II heats the slurry to the washing temperature using a jacketed heat transfer medium; the filter cake from vacuum filter I enters jet washing tank II via a screw conveyor; the ferric phosphate slurry from jet washing tank II enters the coupler via a power fluid pump, simultaneously drawing in washing water from the washing water buffer tank of vacuum filter II; the mixed liquid from the coupler enters the ejector; the slurry from the ejector enters jet washing tank II; the slurry from jet washing tank II enters vacuum filter II via the jet washing tank II discharge pump; the temperature inside jet washing tank II is 70℃, and the pressure is atmospheric pressure; the washing water to pickling solution (based on the initial amount added from the batching tank) feeds into the washing water buffer tank of vacuum filter II at a ratio of 5:1 (mass ratio); the washing water flow rate to the washing water buffer tank of vacuum filter II is 2170 kg / h; the material residence time is 1.0 h;

[0169] 11) The vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry from jet washing tank II enters vacuum filter II via the discharge pump of jet washing tank II, and the mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of vacuum filter II; the filter cake is washed with process water, and the washing water of the filter cake is collected in the washing water buffer tank of vacuum filter II and then enters jet washing tank II; the filter cake of vacuum filter II enters flash dryer via screw conveyor; the temperature of vacuum filter II is room temperature, and the pressure is 0.02 MPa; the ratio of process water to pickling solution (based on the initial amount added to the batching tank) is 6:1 (mass ratio), the feed process water is 2604 kg / h; the wet basis moisture content of the filter cake is 40%;

[0170] 12) The fan of the flash dryer provides power to the flash dryer, and the air heater provides heat to the flash dryer; the filter cake from vacuum filter II enters the flash dryer via a screw conveyor; air enters the flash dryer after passing through the air heater; the dried ferric phosphate and drying exhaust gas are separated by a cyclone separator and a bag filter to separate the ferric phosphate powder and drying exhaust gas; the separated drying exhaust gas is vented, and the separated ferric phosphate powder enters the battery ferric phosphate silo via a star feeder; the outlet air temperature of the flash dryer air heater is 260℃, and the outlet gas temperature of the flash dryer is 120℃; the standard air volume is 12 (air volume kg / wet material kg), and the standard air volume is 3721 kg / h, i.e., 2874 Nm³. 3 1 / h; the moisture content of the dried material at the outlet is less than 0.5%; the output of iron phosphate (FePO4·2H2O) for batteries is 180 kg / h.

[0171] This invention discloses an apparatus and method for preparing battery-grade iron phosphate based on a jet reactor. The prepared battery-grade iron phosphate (FePO4·2H2O) conforms to the HG / T 4701-2014 standard.

[0172] The above technical solutions illustrate the technical concept of the present invention, but should not be construed as limiting the scope of protection of the present invention. Any modifications or alterations made to the above technical solutions based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

Claims

1. An apparatus for preparing battery-grade iron phosphate based on a jet reactor, characterized in that: It includes, in sequence, a batching tank, a jet loop oxidation reactor I, a jet loop oxidation reactor II, a gas-liquid separation tank, a jet loop sedimentation reactor I, a jet loop sedimentation reactor II, a jet washing tank I, a vacuum filter I, a jet washing tank II, a vacuum filter II, and a flash dryer; The mixing tank is used to mix the catalyst and iron source solution evenly. After the mixture reaches the reaction temperature, it enters the jet loop oxidation reactor I. The jet loop oxidation reactor I and jet loop oxidation reactor II are used to carry out the oxidation reaction, that is, to oxidize the ferrous sulfate in the iron source solution into ferric sulfate. The oxidized liquid after the oxidation reaction in jet loop oxidation reactor II enters the gas-liquid separator. The gas-liquid separator is used to separate the unreacted oxygen in the oxidized liquid. The oxidized liquid with separated oxygen enters the jet loop precipitation reactor I. The jet loop precipitation reactor I and jet loop precipitation reactor II are used to precipitate the ferric sulfate solution to generate ferric phosphate. The slurry liquid after the reaction in jet loop precipitation reactor II enters the jet washing tank I. The slurry liquid after the reaction is washed, separated into solid and liquid, and dried by jet washing tank I, vacuum filter I, jet washing tank II, vacuum filter II, and flash dryer to obtain ferric phosphate.

2. The apparatus for preparing battery-grade iron phosphate based on a jet reactor according to claim 1, characterized in that: The device structure is specifically either Device One or Device Two; Device 1: The jet loop oxidation reactor I, jet loop oxidation reactor II, jet loop sedimentation reactor I, jet loop sedimentation reactor II, jet scrubbing tank I, and jet scrubbing tank II all use jet injectors for gas-liquid-solid mixing. The jet generator includes a coupler and an ejector. The coupler is equipped with a power fluid inlet and a gas / liquid inlet. The outer walls of the batching tank, jet loop oxidation reactor I, jet loop oxidation reactor II, gas-liquid separator, jet loop sedimentation reactor I, jet loop sedimentation reactor II, jet washing tank I, and jet washing tank II are all fitted with jackets for introducing a heat medium for heating. Each of the jet loop oxidation reactor I, jet loop oxidation reactor II, jet loop sedimentation reactor I, and jet loop sedimentation reactor II is equipped with a heat exchanger. The material in the reactor is pumped to the heat exchanger for heating before entering the coupler. Device 2: A jet tube oxidation reactor is also provided between the batching tank and the jet loop oxidation reactor I. The jet tube oxidation reactor is used for the oxidation of ferrous sulfate in the iron source solution. The jet tube oxidation reactor, jet loop oxidation reactor I, jet loop oxidation reactor II, jet loop precipitation reactor I, jet loop precipitation reactor II, jet washing tank I, and jet washing tank II all use jet injectors for gas-liquid-solid mixing. The jet-tube oxidation reactor includes an ejector, a jet impact chamber, and a tubular reactor; the jet impact chamber has an ellipsoidal structure, and the tubular reactor has an arc-shaped structure; the ejector is symmetrically arranged at both ends of the jet impact chamber, and the jet impact chamber is connected to the inner cavity of the tubular reactor; the outer wall of the tubular reactor is provided with a jacket; the jacket is used to introduce a heat medium for heating. The jet generator includes a coupler and an ejector. The coupler is provided with a power fluid inlet and a gas / liquid inlet. The mixing tank, jet loop oxidation reactor I, jet loop oxidation reactor II, gas-liquid separator, jet loop sedimentation reactor I, jet loop sedimentation reactor II, jet washing tank I, and jet washing tank II are all equipped with jackets on their outer walls. The jet loop oxidation reactor I, jet loop oxidation reactor II, jet loop sedimentation reactor I, and jet loop sedimentation reactor II are all equipped with heat exchangers. The material in the reactor is transported to the heat exchanger by a fluid pump, heated, and then enters the coupler.

3. The apparatus for preparing battery-grade iron phosphate based on a jet reactor according to claim 2, characterized in that: The device one or device two also includes an oxygen buffer tank, which is used to supply oxygen to the oxidation reactor in the device. The condenser of the gas-liquid separator is connected to the jet loop oxidation reactor I and the jet loop oxidation reactor II. The oxygen in the condenser enters the jet loop oxidation reactor I and the jet loop oxidation reactor II. In either device one or device two, both jet washing tank I and jet washing tank II are equipped with mother liquor buffer tanks. The mother liquor buffer tanks are used to collect the mother liquor separated by vacuum filter I and vacuum filter II, respectively. The mother liquor collected by the mother liquor buffer tank of jet washing tank I is used for ammonium salt recovery, and the mother liquor collected by the mother liquor buffer tank of jet washing tank II is used for filter cake washing of vacuum filter I. Both jet washing tank I and jet washing tank II are equipped with washing water buffer tanks. The washing water buffer tanks are used to collect the washing water from vacuum filter I and vacuum filter II, respectively. The collected washing water then enters jet washing tank I and jet washing tank II, respectively.

4. A method for preparing battery-grade iron phosphate based on the apparatus of claim 2, characterized in that: The method for preparing battery-grade iron phosphate using apparatus one specifically includes the following steps: (1) The steelmaking flue dust acid solution and catalyst are added to the batching tank and mixed evenly under the action of mechanical stirring; the mixture reaches the reaction temperature under the heating of the heat medium and enters the jet loop oxidation reactor I through the batching tank discharge pump; (2) The jacketed heat medium of the jet loop oxidation reactor I provides auxiliary heat for the oxidation reaction, and the heat exchanger provides the main heat for the oxidation reaction. The mixed liquid from the feed tank enters the jet loop oxidation reactor I, and enters the heat exchanger through the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in oxygen. The gas-liquid mixture from the coupler enters the ejector. The gas and liquid from the ejector enter the jet loop oxidation reactor I together. The gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together. (3) The heat medium in the jacket and heat exchanger of the jet loop oxidation reactor II heats the mixed liquid to the oxidation reaction temperature; the gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together, and enter the heat exchanger through the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in oxygen; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reactor II together; the gas and liquid overflowing from the jet loop oxidation reactor II enter the gas-liquid separator tank together. (4) The unreacted oxygen in the oxidizing liquid in the gas-liquid separator is separated out by the condenser under the action of mechanical stirring; the oxidizing liquid with separated oxygen enters the jet loop sedimentation reactor I through the gas-liquid separator discharge pump. (5) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor I heats the oxidizing liquid to the precipitation reaction temperature; the ferric sulfate solution from the discharge pump of the gas-liquid separator and the phosphoric acid from the phosphoric acid tank enter the jet loop sedimentation reactor I, and enter the heat exchanger through the power fluid pump. After being heated by the heat exchanger, it enters the coupler and simultaneously draws in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry liquid from the ejector enters the jet loop sedimentation reactor I; the slurry liquid overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II; (6) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor II heats the slurry to the sedimentation reaction temperature; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II, enters the heat exchanger via a power fluid pump, and after being heated by the heat exchanger, enters the coupler while simultaneously drawing in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet loop sedimentation reactor II; the slurry overflowing from the jet loop sedimentation reactor II enters the jet washing tank I; (7) The heat medium in the jacket of the jet washing tank I heats the slurry to the washing temperature; the slurry overflowing from the jet loop sedimentation reactor II enters the jet washing tank I, and enters the coupler through the power fluid pump while simultaneously drawing in washing water. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet washing tank I; the slurry from the jet washing tank I enters the vacuum filter I through the discharge pump of the jet washing tank I. (8) The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry of jet washing tank I enters vacuum filter I through the discharge pump of jet washing tank I, and the filter cake of vacuum filter I enters jet washing tank II through screw conveyor; (9) The heat medium in the jacket of the jet washing tank II heats the slurry to the washing temperature; the filter cake of vacuum filter I enters the jet washing tank II through the screw conveyor; the ferric phosphate slurry of jet washing tank II enters the coupler through the power fluid pump and simultaneously draws in washing water; the mixed liquid from the coupler enters the ejector; the slurry from the ejector enters the jet washing tank II; the slurry of jet washing tank II enters the vacuum filter II through the discharge pump of jet washing tank II. (10) The vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry of jet washing tank II enters vacuum filter II through the discharge pump of jet washing tank II, and the filter cake of vacuum filter II enters flash dryer through screw conveyor. (11) The iron phosphate and the drying exhaust gas after flash drying are separated by a cyclone separator and a bag filter. The separated iron phosphate powder enters the iron phosphate silo for batteries. The method for preparing battery-grade iron phosphate using apparatus two specifically includes the following steps: 1) The pickling solution and catalyst from the steel plant are added to the mixing tank and mixed evenly under the action of mechanical stirring. The mixture reaches the reaction temperature under the heating of the heat medium and enters the jet tube oxidation reactor through the discharge pump of the mixing tank. 2) The mixed liquid in the jet tube oxidation reactor reaches the oxidation reaction temperature under the heating of the jacket heat medium. The mixed liquid from the feed tank discharge pump enters the symmetrical coupler of the jet tube oxidation reactor, and oxygen is drawn in at the same time. The gas-liquid mixture from the coupler enters the ejector, is impacted in the jet impact chamber and then enters the tubular reactor. The oxidation mixture from the tubular reactor enters the jet loop oxidation reactor I. 3) The heat medium in the jacket and heat exchanger of jet loop oxidation reactor I heats the mixed liquid to the oxidation reaction temperature; the gas and liquid from the jet tube oxidation reactor enter jet loop oxidation reactor I together, and are then pumped into the heat exchanger by the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, the mixture enters the coupler and simultaneously draws in oxygen; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter jet loop oxidation reactor I together; the gas and liquid overflowing from jet loop oxidation reactor I enter jet loop oxidation reactor II together. 4) The heat medium in the jacket and heat exchanger of the jet loop oxidation reactor II heats the mixed liquid to the oxidation reaction temperature; the gas and liquid overflowing from the jet loop oxidation reactor I enter the jet loop oxidation reactor II together, and are then pumped into the heat exchanger by the gas-liquid mixing power fluid pump. After being heated by the heat exchanger, the mixture enters the coupler while simultaneously drawing in oxygen; the gas-liquid mixture from the coupler enters the ejector, and the gas and liquid from the ejector enter the jet loop oxidation reactor II together; the gas and liquid overflowing from the jet loop oxidation reactor II enter the gas-liquid separator tank together. 5) The unreacted oxygen in the oxidizing liquid in the gas-liquid separator is separated out by the condenser under the action of mechanical stirring; the oxidizing liquid with separated oxygen enters the jet loop sedimentation reactor I through the gas-liquid separator discharge pump. 6) The heat medium in the jacket and heat exchanger of jet loop sedimentation reactor I heats the oxidizing liquid to the precipitation reaction temperature; the ferric sulfate solution from the discharge pump of the gas-liquid separator and the phosphoric acid from the phosphoric acid tank enter the jet loop sedimentation reactor I, and are then pumped into the heat exchanger. After being heated by the heat exchanger, they enter the coupler and simultaneously draw in ammonia from the ammonia tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet loop sedimentation reactor I; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II; 7) The heat medium in the jacket and heat exchanger of the jet loop sedimentation reactor II heats the slurry to the sedimentation reaction temperature; the slurry overflowing from the jet loop sedimentation reactor I enters the jet loop sedimentation reactor II, is pumped into the heat exchanger, is heated by the heat exchanger, and then enters the coupler while simultaneously drawing in ammonia water from the ammonia water tank; the mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters the jet loop sedimentation reactor II; the slurry overflowing from the jet loop sedimentation reactor II enters the jet washing tank I; 8) The jacketed heat transfer medium in jet washing tank I heats the slurry to the washing temperature; the slurry overflowing from the jet loop sedimentation reactor II enters jet washing tank I, and is pumped into the coupler by a power fluid pump while simultaneously drawing in washing water. The mixed liquid from the coupler enters the ejector, and the slurry from the ejector enters jet washing tank I; the slurry from jet washing tank I enters vacuum filter I via the jet washing tank I discharge pump. 9) The vacuum pump of vacuum filter I provides vacuum for vacuum filter I; the slurry of jet washing tank I enters vacuum filter I through the discharge pump of jet washing tank I, and the filter cake of vacuum filter I enters jet washing tank II through screw conveyor; 10) The heat transfer medium in the jacket of jet washing tank II heats the slurry to the washing temperature; the filter cake from vacuum filter I enters jet washing tank II via a screw conveyor; the ferric phosphate slurry in jet washing tank II enters the coupler via a power fluid pump and simultaneously draws in washing water; the mixed liquid from the coupler enters the ejector; the slurry from the ejector enters jet washing tank II; the slurry from jet washing tank II enters vacuum filter II via the discharge pump of jet washing tank II. 11) The vacuum pump of vacuum filter II provides vacuum for vacuum filter II; the slurry of jet washing tank II enters vacuum filter II through the discharge pump of jet washing tank II, and the filter cake of vacuum filter II enters flash dryer through screw conveyor. 12) After being dried by the flash dryer, the iron phosphate powder and the drying exhaust gas are separated by a cyclone separator and a bag filter. The separated iron phosphate powder enters the iron phosphate silo for batteries.

5. The method for preparing battery-grade iron phosphate according to claim 4, characterized in that: Apparatus 1: In the acid solution of steelmaking flue dust in step (1), the molar ratio of FeSO4 to H2SO4 is 1:0.5, and the molar ratio of FeSO4 to Fe2(SO4)3 is 1:0.85; the temperature in the mixing tank is 80℃~90℃, the pressure is 0.15MPa~0.2MPa, the catalyst mass is 1.4%~1.6% of FeSO4, the mass concentration of FeSO4 is 8.5%~9%, and the residence time of the material is 0.5h~0.75h; Device 2: In step 1), the molar ratio of FeSO4 to H2SO4 in the steel plant pickling solution is 1:0.5; the temperature in the mixing tank is 80℃~90℃, the pressure is 0.15MPa~0.2MPa, the catalyst mass is 0.4%~0.45% of the pickling solution, the FeSO4 mass concentration is 30%~35%, and the material residence time is 0.5h~0.75h.

6. The method for preparing battery-grade iron phosphate according to claim 4, characterized in that: The process conditions for the oxidation reaction in the device are as follows: Device 1: The temperature in the step (2) jet flow loop oxidation reactor I is 80-90 DEG C, the pressure is 0.45-0.5 MPa, the material out of the heat exchanger is 80-90 DEG C, the pressure is 0.45-0.5 MPa; the oxygen and FeSO4 molar ratio of the coupling device feed is (0.2-0.25):1, namely (4.5-5.6) Nm 3 :1 kmol; the material residence time is 1-1.5 h; The temperature in the step (3) jet flow loop oxidation reactor II is 80-90°C, the pressure is 0.4-0.45 MPa, the material out of the heat exchanger is 80-90°C, the pressure is 0.4-0.45 MPa; the oxygen and FeSO4 molar ratio of the coupling device is (0.2-0.25):1, namely (4.5-5.6) Nm 3 :1 kmol; the material residence time is 1.5-2 h; Device 2: In step 2), the temperature inside the jet-tube oxidation reactor is 80℃~90℃, and the pressure is 0.5MPa~0.6MPa; the oxygen:FeSO4 molar ratio in the coupler feed is (0.15~0.2):1, i.e., (3.4~4.5) Nm³. 3 1 kmol; In step 3), the temperature inside the jet loop oxidation reactor I is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa. The material outlet temperature from the heat exchanger is 80℃~90℃, and the pressure is 0.45MPa~0.5MPa. The oxygen:FeSO4 molar ratio in the coupler feed is (0.15~0.2):1, i.e., (3.4~4.5) Nm³. 3 1 kmol; residence time of the material is 1 h to 1.5 h; In step 4), the temperature inside the jet loop oxidation reactor II is 80℃~90℃, and the pressure is 0.4MPa~0.45MPa. The material outlet temperature from the heat exchanger is 80℃~90℃, and the pressure is 0.4MPa~0.45MPa. The oxygen:FeSO4 molar ratio in the coupler feed is (0.15~0.2):1, i.e., (3.4~4.5) Nm³. 3 1 kmol; residence time of the material is 1.5 h to 2 h; FeSO4 is calculated based on the initial amount added to the mixing tank.

7. The method for preparing battery-grade iron phosphate according to claim 4, characterized in that: In step (4) or step (5), the oxygen separated by the condenser of the gas-liquid separator enters the coupler of jet loop oxidation reactor I and the coupler of jet loop oxidation reactor II; the jacket of the gas-liquid separator maintains the temperature of the oxidizing liquid at 70℃~80℃ and the pressure inside the tank is atmospheric pressure; the residence time of the material is 0.5h~1h.

8. The method for preparing battery-grade iron phosphate according to claim 4, characterized in that: The process conditions for the precipitation reaction in the apparatus are as follows: Device 1: In step (5), the temperature inside the jet loop sedimentation reactor I is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃~80℃; the feed mass concentration of 30% phosphoric acid: FeSO4 is 2.8:1~2.9:1 based on the initial amount added from the batching tank; the feed mass concentration of 20% ammonia water: FeSO4 to the coupler is 4.6:1~4.8:1 based on the initial amount added from the batching tank; the material residence time is 1.5h~2h. In step (6), the temperature inside the jet loop sedimentation reactor II is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature of the heat exchanger is 70℃~80℃; the feed mass concentration of ammonia water with a mass concentration of 20% to FeSO4 is 4.6:1~4.8:1 based on the initial amount added in the batching tank; the residence time of the material is 1.5h~2h. Device 2: In step 6), the temperature inside the jet loop sedimentation reactor I is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃~80℃; the feed mass concentration of 30% phosphoric acid: the molar ratio of FeSO4 is 1.03:1~1.05:1; the feed mass concentration of 20% ammonia water: the molar ratio of FeSO4 to the coupler is 1.8:1~1.9:1; and the material residence time is 1.5h~2h. In step 7), the temperature inside the jet loop sedimentation reactor II is 70℃~80℃, the pressure is atmospheric pressure, and the material outlet temperature from the heat exchanger is 70℃~80℃; the molar ratio of 20% ammonia water to FeSO4 in the feed to the coupler is 1.8:1~1.9:1; and the material residence time is 1.5h~2h. FeSO4 is calculated based on the initial amount added to the mixing tank.

9. The method for preparing battery-grade iron phosphate according to claim 4, characterized in that: The washing process conditions in the device are as follows: In step (7) or step (8), the temperature inside the jet washing tank I is 60℃~70℃ and the pressure is atmospheric pressure; the washing water in the washing water buffer tank of the coupler feed vacuum filter I has a mass ratio of steelmaking flue dust acid solution / pickling liquid of 5:1~6:1; the residence time of the material is 1.0h~1.5h. In step (8) or step (9), the slurry from jet washing tank I enters vacuum filter I via the discharge pump of jet washing tank I. The mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of jet washing tank I. Then, the mother liquor enters the ammonium salt mother liquor tank for ammonium salt recovery. The mother liquor from jet washing tank II washes the filter cake, and the washing water from the filter cake is collected in the washing water buffer tank of vacuum filter I and then enters jet washing tank I. The filter cake from vacuum filter I enters jet washing tank II via a screw conveyor. The temperature of vacuum filter I is room temperature, and the pressure is 0.02 MPa to 0.01 MPa. The mass ratio of the mother liquor in jet washing tank II to steelmaking flue dust acid solution / pickling solution is 5:1 to 6:

1. The wet basis moisture content of the filter cake is 35% to 40%. In step (9) or step (10), the temperature inside the jet washing tank II is 60℃~70℃ and the pressure is atmospheric pressure; the washing water in the washing water buffer tank of the coupler feed vacuum filter II has a mass ratio of steelmaking flue dust acid solution / pickling liquid of 5:1~6:1; the residence time of the material is 1.0h~1.5h. In step (10) or step (11), the slurry from jet washing tank II enters vacuum filter II via the discharge pump of jet washing tank II, and the mother liquor is separated in the vacuum chamber and enters the mother liquor buffer tank of vacuum filter II. The filter cake is washed with process water, and the wash water is collected in the wash water buffer tank of vacuum filter II, and then enters jet washing tank II; the filter cake from vacuum filter II enters flash dryer via screw conveyor; the temperature of vacuum filter II is room temperature, and the pressure is 0.02MPa~0.01MPa; the mass ratio of process water: steelmaking flue dust acid solution / pickling solution is 5:1~6:1; the wet basis moisture content of the filter cake is 35%~40%; Among them, the acid solution / pickling solution for steelmaking flue dust is calculated based on the initial amount added to the batching tank.

10. The method for preparing battery-grade iron phosphate according to claim 4, characterized in that: In step (11) or step (12), the fan of the flash dryer provides power to the flash dryer, and the air heater provides heat to the flash dryer; the filter cake of vacuum filter II enters the flash dryer via a screw conveyor; the air enters the flash dryer after passing through the air heater, and the dried iron phosphate and the drying exhaust gas are separated by a cyclone separator and a bag filter to separate the iron phosphate powder and the drying exhaust gas. The separated drying exhaust gas is released into the atmosphere, and the separated iron phosphate powder enters the iron phosphate silo for batteries via a star feeder; the outlet air temperature of the flash dryer air heater is 255℃~260℃, and the outlet gas temperature of the flash dryer is 115℃~120℃; the standard air volume is 11.5~12, and the air volume is kg / kg of wet material; the wet basis moisture content of the dried material at the outlet is less than 0.5%.

Images