A method and device for recovering phosphorus from lithium iron phosphate recovery slag

Abstract

The present invention discloses a phosphorus recovery method and device for lithium iron phosphate recovery slag, and relates to the technical field of pyrometallurgical phosphorus recovery equipment. The method and device comprise a blast furnace, a conveyor belt, a material addition component, and a reaction material addition cylinder. The reaction material addition cylinder is located between the blast furnace and the material addition component. The material addition component comprises a screening mechanism and a crushing mechanism. The screening mechanism comprises a screening box, and a feed hopper is provided on the top of the screening box. The present invention is provided with a material addition component on one side of the conveyor belt. The material addition component comprises a screening mechanism and a crushing mechanism. The material is screened by the screening mechanism, and the large material particles are crushed again by the crushing mechanism, thereby improving the crushing effect of the material and achieving the crushing of the material when adding the material. There is no need to purchase completely crushed lithium iron phosphate recovery slag, which not only reduces the recovery cost of the recovery slag, but also prevents the possible agglomeration of the lithium iron phosphate slag, increases the contact area between the recovery slag and the reaction material, and improves the production capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of pyrometallurgical phosphorus recovery, and in particular to a method and device for recovering phosphorus from lithium iron phosphate recovery slag. Background Art

[0002] In the process of pyrometallurgical phosphorus recovery, lithium iron phosphate recovery slag has a high value because of its low price and good safety.

[0003] Lithium iron phosphate recovery residue contains a large amount of iron phosphate. Existing methods for recovering lithium iron phosphate residue primarily use high-concentration inorganic acids such as sulfuric acid and phosphoric acid to dissolve the iron phosphate. Alkali is then added to the leachate to adjust the pH and precipitate the iron phosphate. However, this leaching and precipitation process requires large amounts of acid and alkali, resulting in high reagent costs, low economic returns, and a large amount of waste salt. Furthermore, strong acids are highly corrosive to equipment. Furthermore, the leaching rate of iron and phosphorus during strong acid leaching is low, resulting in a waste of iron and phosphorus resources.

[0004] In the prior art, phosphorus is obtained by heating the iron phosphate in lithium iron phosphate and reactants to produce phosphorus. To improve the reaction efficiency, reduce recovery time, and increase production capacity, commercially available lithium iron phosphate recovery slag is generally fully crushed to increase the contact area between the material and the reactants. However, the price of fully crushed lithium iron phosphate recovery slag is high, which increases the cost of phosphorus recovery from the lithium iron phosphate recovery slag. In addition, the recycled lithium iron phosphate slag may agglomerate, resulting in a small contact area between the recovery slag and the reactants, resulting in an incomplete reaction and reduced production capacity. Summary of the Invention

[0005] The object of the present invention is to provide a method and apparatus for recovering phosphorus from lithium iron phosphate recovery slag, so as to solve the problems raised in the above background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solutions: a method and apparatus for recovering phosphorus from lithium iron phosphate recovery slag, comprising a blast furnace, a conveyor belt, a material addition assembly, and a reaction material addition cylinder, wherein the reaction material addition cylinder is located between the blast furnace and the material addition assembly, and the material addition assembly comprises a screening mechanism and a crushing mechanism;

[0007] The screening mechanism includes a screening box, a feed hopper is provided on the top of the screening box, a filter assembly is provided inside the screening box, and the filter assembly includes a guide plate and a first filter plate. Both sides of the guide plate are fixed to the side walls of the screening box. The first filter plate is located on the top of the guide plate and is movably arranged in the screening box.

[0008] The crushing mechanism includes a crushing cylinder, a crushing assembly is provided on the top of the crushing cylinder, and the crushing assembly crushes the large particles of materials. The bottom of the crushing cylinder is fixedly connected to a discharge hopper, which is located just above the conveyor belt.

[0009] A first communicating groove and a second communicating groove are provided on one side of the pulverizing cylinder. The first filter plate is movably arranged in the first communicating groove. The bottom of the material guide plate is fixed to the bottom wall of the second communicating groove.

[0010] Furthermore, the material guide plate and the first filter plate divide the inner cavity of the screening box into a top cavity, a middle cavity and a bottom cavity, and dust removal components are provided outside the top cavity and the middle cavity.

[0011] Furthermore, the dust removal assembly includes a fan hole opened on the side of the screening box and connected to the top cavity and the middle cavity, an electronic fan is fixed in the fan hole, a dust cover is fixed outside the fan hole, the dust cover is connected to the air intake pipe through a connecting pipe, and the air intake pipe is connected to the bottom cavity;

[0012] Several filter screens are arranged in the bottom cavity, and an air outlet pipe is fixedly connected to the outside of the screening box. The gas enters the bottom cavity through the air inlet pipe, is filtered by the filter screen, and is discharged through the air outlet pipe.

[0013] Furthermore, the filter assembly also includes a plurality of support columns fixed on the top of the guide plate, a spring is fixed between the top of the support column and the first filter plate, and a vibration motor is fixed at the bottom of the first filter plate.

[0014] Furthermore, the crushing assembly includes a roller connected in a rolling manner to the crushing cylinder and a rotating motor fixed to the top of the crushing cylinder;

[0015] A plurality of connecting rods are fixed to the bottom of the roller, a sleeve shaft is fixed on the rod body of the connecting rod, a plurality of protrusions are arranged on the shaft body of the sleeve shaft, and the sleeve shaft is located at the bottom of the discharge port of the first filter plate.

[0016] Furthermore, a crushing assembly is provided at the bottom of the crushing assembly, and the crushing assembly includes a second filter plate and a crushing part.

[0017] Furthermore, the crushing part includes two support frames, and the first movable shaft and the second movable shaft are respectively connected in a rolling manner on the two support frames, the bottom end of the roller is fixed with a first gear, the top and bottom of the first movable shaft are respectively fixed with a second gear and a third gear, and the top and bottom of the second movable shaft are respectively fixed with a fourth gear and a U-shaped plate;

[0018] The first gear and the second gear are meshed, and the third gear and the fourth gear are meshed;

[0019] The bottom of the U-shaped plate is connected to a rolling roller;

[0020] The discharge side of the guide plate is located at the bottom of the second filter plate.

[0021] Furthermore, a top inclined plate and a bottom inclined plate are fixed to the bottom of the discharge hopper, and the length of the top inclined plate is smaller than that of the bottom inclined plate.

[0022] A method for recovering phosphorus from lithium iron phosphate recovery slag comprises the following steps:

[0023] Step 1: Open the feed pipe on the blast furnace, start the conveyor belt motor, put the lithium iron phosphate and the reaction material into the screening mechanism and the reaction material adding cylinder respectively, and the material and the reaction material fall onto the conveyor belt and are conveyed by the conveyor belt. Finally, they enter the blast furnace through the feed pipe. After the material addition is completed, close the feed pipe;

[0024] Step 2: Use an air pump to evacuate the inner cavity of the blast furnace to a vacuum;

[0025] Step 3: The mixed material is heated in a blast furnace at a temperature of - degrees Celsius for a time of - hours;

[0026] Step 4: The gas generated by heating the material is connected to the separation chamber through a pipeline;

[0027] Step 5: The temperature of the separation chamber is lowered to - degrees Celsius by a refrigeration device attached to the outside of the separation chamber. At this time, the phosphorus vapor solidifies to form solid phosphorus. The remaining gas in the separation chamber is pumped away by an air pump to obtain solid phosphorus.

[0028] Furthermore, the reaction material in step 1 is a mixture of carbon and silicon dioxide, and the mass ratio thereof is 1:(1-3).

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The phosphorus recovery method and device for lithium iron phosphate recovery slag are provided with a material adding component on one side of a conveyor belt. The material adding component includes a screening mechanism and a crushing mechanism. The material is screened by the screening mechanism and large material particles are crushed again by the crushing mechanism, thereby improving the crushing effect of the material and achieving crushing of the material when adding the material. There is no need to purchase completely crushed lithium iron phosphate recovery slag, which not only reduces the recovery cost of the recovery slag, but also prevents the possible agglomeration of the lithium iron phosphate slag, increases the contact area between the recovery slag and the reaction material, and improves the production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 A side axial view of the crushing mechanism and screening mechanism of the present invention;

[0033] Figure 3 Another side axial view of the crushing mechanism and screening mechanism of the present invention;

[0034] Figure 4 A half-section diagram of the crushing mechanism and screening mechanism of the present invention;

[0035] Figure 5 This is a cross-sectional view of the crushing mechanism and screening mechanism of the present invention.

[0036] In the figure: 1. blast furnace; 2. conveyor belt; 3. crushing mechanism; 301. discharge hopper; 4. screening mechanism; 401. feed hopper; 5. reaction material adding cylinder; 6. dust removal assembly; 601. dust hood; 602. exhaust pipe; 603. electronic fan; 604. filter screen; 701. guide plate; 702. support column; 703. vibration motor; 704. first filter plate; 801. roller; 802. rotating motor; 803. sleeve shaft; 804. protrusion; 805. second filter plate; 9. crushing assembly; 901. second gear; 902. fourth gear; 903. support frame; 904. U-shaped plate; 905. crushing roller; 101. top inclined plate; 102. bottom inclined plate. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] like Figure 1-Figure 5 As shown, the present invention provides a technical solution: a method and device for recovering phosphorus from lithium iron phosphate recovery slag, comprising a blast furnace 1, a conveyor belt 2, a material adding assembly and a reaction material adding cylinder 5, wherein the reaction material adding cylinder 5 is located between the blast furnace 1 and the material adding assembly, wherein the material adding assembly includes a screening mechanism 4 and a crushing mechanism 3;

[0039] like Figure 4 As shown, the screening mechanism 4 includes a screening box, the crushing mechanism 3 includes a crushing cylinder, a feed hopper 401 is provided on the top of the screening box, and a filter assembly for filtering lithium iron phosphate (hereinafter referred to as material) is provided inside the screening box, wherein the filter assembly includes a guide plate 701 and a first filter plate 704. It should be noted that both sides of the guide plate 701 are fixed to the side walls of the screening box, and the first filter plate 704 is located on the top of the guide plate 701 and is movably provided in the screening box;

[0040] A plurality of support columns 702 are fixed to the top of the guide plate 701 , a spring is fixed between the top of the support column 702 and the first filter plate 704 , and a vibration motor 703 is fixed to the bottom of the first filter plate 704 .

[0041] A first communicating groove and a second communicating groove are provided on one side of the pulverizing cylinder. The first filter plate 704 is movably arranged in the first communicating groove. The bottom of the guide plate 701 is fixed to the bottom wall of the second communicating groove.

[0042] Specifically, the material is put into the top of the first filter plate 704 through the feed hopper 401, and the controller controls the vibration motor 703 to start. Under the vibration force of the vibration motor 703 and the elastic force of the spring, the first filter plate 704 is vibrated, and the material moves downward on the first filter plate 704. During the movement, small particles of material fall into the guide plate 701 through the filter holes of the first filter plate 704, and enter the crushing mechanism 3 through the guide plate 701.

[0043] like Figure 4 and Figure 5 As shown, a crushing assembly is provided on the top of the crushing cylinder. It can be understood that the crushing assembly crushes large particles of material. A discharge hopper 301 is fixedly connected to the bottom of the crushing cylinder. The discharge hopper 301 is located directly above the conveyor belt 2. In this way, the crushed material falls onto the conveyor belt 2 through the discharge hopper 301 for transportation.

[0044] In order to clean up the dust generated by the materials and reduce environmental pollution, such as Figure 2 、 Figure 3 and Figure 5 As shown, the material guide plate 701 and the first filter plate 704 divide the inner cavity of the screening box into a top cavity, a middle cavity and a bottom cavity, and a dust removal assembly 6 is provided outside the top cavity and the middle cavity.

[0045] Among them, the dust removal component 6 includes a fan hole opened on the side of the screening box and connected to the top cavity and the middle cavity. An electronic fan 603 is fixed in the fan hole, and a dust cover 601 is fixed on the outside of the fan hole. The dust cover 601 is connected to the air inlet pipe connected to the bottom cavity through a connecting pipe. In order to filter the dust, no less than two filter screens 604 are arranged in the bottom cavity. The filter apertures of the filter screens 604 decrease from left to right to achieve graded filtration and improve the filtration effect. An outlet pipe 602 is fixedly connected to the outside of the screening box. The gas enters the bottom cavity through the air inlet pipe, and is discharged through the outlet pipe 602 after being filtered by the filter screen 604.

[0046] like Figure 2 As shown, a door is provided on the left side of the screening box. After filtering for a period of time, the door is opened and the filter 604 and the dust in the bottom cavity are manually cleaned.

[0047] In order to crush the large particles flowing down from the first filter plate 704, thereby increasing the contact area between the materials and the reaction materials and improving the phosphorus recovery efficiency, Figure 4 and Figure 5As shown, the crushing assembly includes a roller 801 that is rollingly connected to the crushing cylinder and a rotating motor 802 fixed to the top of the crushing cylinder, and the output end of the rotating motor 802 is fixed to the top of the roller 801;

[0048] Four connecting rods are fixed in a ring shape at the bottom of the roller 801, and a sleeve 803 is fixed on the rod body of the connecting rod. Several protrusions 804 are provided on the shaft body of the sleeve 803. The protrusions 804 are provided to increase the impact force on the material and improve the crushing effect. It can be known that the sleeve 803 is located at the bottom of the discharge port of the first filter plate 704.

[0049] Specifically, the controller controls the rotating motor 802 to start, and the rotating motor 802 drives the sleeve shaft 803 to rotate rapidly around the roller 801 axis. The large particle material passes through the first filter plate 704 and enters the crushing barrel. When falling, the protrusion 804 collides with the material, thereby crushing the material.

[0050] In order to further improve the crushing effect, Figure 4 and Figure 5 As shown, a crushing assembly 9 is provided at the bottom of the crushing assembly, and the crushing assembly 9 includes a second filter plate 805 and a crushing part.

[0051] Among them, Figure 5 As shown, the crushing part includes two support frames 903, and the first movable shaft and the second movable shaft are respectively connected in a rolling manner on the two support frames 903. The bottom end of the roller 801 is fixed with a first gear, the top and bottom of the first movable shaft are respectively fixed with a second gear 901 and a third gear, and the top and bottom of the second movable shaft are respectively fixed with a fourth gear 902 and a U-shaped plate 904. It can be seen that the first gear and the second gear 901 are meshed with each other, and the third gear and the fourth gear 902 are meshed with each other. The gear ratio of the first gear, the second gear 901, the third gear and the fourth gear 902 is: 1: (3-10): 1: (3-10);

[0052] A rolling roller 905 is connected to the bottom of the U-shaped plate 904 in a rolling manner;

[0053] It can be known that the four gears cooperate with each other to achieve deceleration of the rolling roller 905, thereby preventing the rolling roller 905 from rotating too fast and affecting the passage of materials through the second filter plate 805.

[0054] The discharge side of the guide plate 701 is located at the bottom of the second filter plate 805. In this way, the material filtered by the first filter plate 704 will directly enter the bottom of the crushing cylinder, reducing the working intensity of the crushing part.

[0055] Specifically, the material crushed by the sleeve shaft 803 falls onto the top of the second filter plate 805, the small particle material falls into the discharge hopper 301 through the filter hole, and a small part of the large particle material is blocked by the second filter plate 805. Through the mutual cooperation of the four gears, the rolling roller 905 rotates around the second movable axis, and the rolling roller 905 rolls the large particle material on the second filter plate 805, thereby achieving the crushing of the large particle material and improving the mixing effect of the material and the reaction material.

[0056] To prevent material accumulation, such as Figure 5 As shown, a top inclined plate 101 and a bottom inclined plate 102 are fixed at the bottom of the discharge hopper 301 , and the length of the top inclined plate 101 is smaller than that of the bottom inclined plate 102 .

[0057] In this way, the material falls to the top of the top inclined plate 101 through the discharge hopper 301, and the material moves downward through the top inclined plate 101. During the falling process, the material can be spread flat on the top of the bottom inclined plate 102, and finally transported by the conveyor belt 2. When the material is transported to the bottom of the reaction material addition cylinder 5, the controller controls the material valve at the bottom of the reaction material addition cylinder 5 to open, and the reaction material falls to the top of the conveyor belt 2 and contacts with the material. The setting of the top inclined plate 101 and the bottom inclined plate 102 can effectively reduce material accumulation and further improve the mixing effect of the material and the reaction material.

[0058] A method for recovering phosphorus from lithium iron phosphate recovery slag comprises the following steps:

[0059] Step 1: Open the feed pipe on the blast furnace 1, start the motor of the conveyor belt 2, put the lithium iron phosphate and the reaction material into the screening mechanism 4 and the reaction material adding cylinder 5 respectively, and the material and the reaction material fall onto the conveyor belt 2 and are conveyed by the conveyor belt 2. Finally, they enter the blast furnace 1 through the feed pipe. After the material addition is completed, close the feed pipe;

[0060] The reaction material is a mixture of carbon and silicon dioxide, with a mass ratio of 1:(1-3).

[0061] Step 2: Pump the inner cavity of the blast furnace 1 to a vacuum state by using an air pump;

[0062] Step 3: The mixture is heated in a blast furnace 1 at a temperature of 1300-1600 degrees Celsius for 3-8 hours.

[0063] Step 4: The gas generated by heating the material is connected to the separation chamber through a pipeline;

[0064] Step 5: Use a refrigeration device attached to the outside of the separation chamber to reduce the temperature of the separation chamber to 5-30 degrees Celsius. At this time, the phosphorus vapor solidifies to form solid phosphorus. The remaining gas in the separation chamber is pumped away by an air pump to obtain solid phosphorus.

[0065] To supplement this plan, the lithium iron phosphate recovery slag contains a large amount of iron phosphate. This plan is to recover phosphorus in the iron phosphate through pyrolysis. The reaction equation is: 2FePO4+5C+SiO2→Fe2O3.SiO2+5CO+2P↑.

[0066] In actual production, this equipment can also be used for thermal decomposition and recovery of other waste residues. In order to detect whether various phosphorus-containing waste residues can decompose at different temperatures and whether the phosphorus therein can be reduced to elemental phosphorus and overflow, various samples are prepared for inspection tests.

[0067] Equipment required for the experiment:

[0068] High temperature tube furnace, muffle furnace, graphite crucible, grinding equipment, electronic balance.

[0069] Raw materials used in the experiment:

[0070] Waste iron phosphate (phosphorus content about 20.7%), silicon dioxide powder (analytical grade), anthracite, argon, and nitrogen.

[0071] Test method:

[0072] The phosphorus-containing waste slag is calcined at high temperature under a reducing atmosphere, and then the phosphorus content in the calcined residue is compared with that in the phosphorus-containing waste slag before calcination.

[0073] Step 1: Mix the phosphorus-containing waste residue, silicon dioxide powder and anthracite in a certain proportion and grind and mix them evenly using a grinding device;

[0074] Step 2: Take an appropriate amount of the mixture, put it into a graphite crucible and place it in a muffle furnace and preheat it to about 800°C;

[0075] Step 3: Then take out the graphite crucible and put it into a high-temperature tube furnace preheated to about 1000°C, heat it to a predetermined temperature and keep it warm for a period of time;

[0076] Step 4: The high-temperature tube furnace is then cooled to 1000 degrees Celsius, the crucible is taken out, and the residue in the crucible is processed and analyzed for phosphorus content.

[0077] Test results: Table 1 is the table of phosphorus content of residue, and Table 2 is the table of raw material testing data.

[0078] Table 1

[0079]

[0080] Table 2

[0081] project P Ca-ppm Mg-ppm Fe-ppm Mn-ppm Al-ppm Ti-ppm Waste iron phosphate 20.7％ 25 57 364300 64 12 9

[0082] It can be seen that after recovery by the method adopted in the present application, the phosphorus content in the raw material is greatly reduced from 20.7% to 0.68% to 0.47%, achieving efficient phosphorus recovery.

[0083] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is limited by the accompanying embodiments and their equivalents.

Claims

1. A phosphorus recovery device for lithium iron phosphate recovery slag, comprising a blast furnace (1), a conveyor belt (2), a material adding assembly and a reaction material adding cylinder (5), wherein the reaction material adding cylinder (5) is located between the blast furnace (1) and the material adding assembly, and is characterized in that: The material adding assembly includes a screening mechanism (4) and a crushing mechanism (3); The screening mechanism (4) includes a screening box, a feed hopper (401) is provided on the top of the screening box, a filter assembly is provided inside the screening box, and the filter assembly includes a guide plate (701) and a first filter plate (704), both sides of the guide plate (701) are fixed to the side walls of the screening box, and the first filter plate (704) is located on the top of the guide plate (701) and is movably provided in the screening box; The crushing mechanism (3) includes a crushing cylinder, a crushing assembly is provided on the top of the crushing cylinder, and the crushing assembly crushes large particles of material. The bottom of the crushing cylinder is fixedly connected to a discharge hopper (301), and the discharge hopper (301) is located directly above the conveyor belt (2); A first connecting groove and a second connecting groove are provided on one side of the pulverizing cylinder. The first filter plate (704) is movably arranged in the first connecting groove. The bottom of the guide plate (701) is fixed to the bottom wall of the second connecting groove. The guide plate (701) and the first filter plate (704) divide the inner cavity of the screening box into a top cavity, a middle cavity and a bottom cavity, and dust removal components (6) are provided outside the top cavity and the middle cavity; The dust removal assembly (6) includes a fan hole provided on the side of the screening box and communicating with the top cavity and the middle cavity, an electronic fan (603) is fixed in the fan hole, a dust cover (601) is fixed outside the fan hole, the dust cover (601) is connected to an air inlet pipe via a connecting pipe, and the air inlet pipe is communicated with the bottom cavity; a plurality of filter screens (604) are provided in the bottom cavity, an air outlet pipe (602) is fixed outside the screening box, and gas enters the bottom cavity through the air inlet pipe, is filtered by the filter screen (604), and is discharged through the air outlet pipe (602); The filter assembly further comprises a plurality of support columns (702) fixed to the top of the guide plate (701), a spring is fixed between the top of the support column (702) and the first filter plate (704), and a vibration motor (703) is fixed to the bottom of the first filter plate (704); The crushing assembly comprises a roller (801) that is rollingly connected to the crushing drum and a rotating motor (802) fixed to the top of the crushing drum; a plurality of connecting rods are fixed to the bottom of the roller (801); a sleeve shaft (803) is fixed to the rod body of the connecting rod; a plurality of protrusions (804) are provided on the shaft body of the sleeve shaft (803); and the sleeve shaft (803) is located at the bottom of the discharge port of the first filter plate (704); A crushing assembly (9) is provided at the bottom of the crushing assembly, and the crushing assembly (9) comprises a second filter plate (805) and a crushing portion.

2. The phosphorus recovery device for lithium iron phosphate recovery slag according to claim 1, characterized in that: The crushing section comprises two support frames (903), a first movable shaft and a second movable shaft being respectively connected in a rolling manner to the two support frames (903), a first gear being fixed to the bottom end of the roller (801), a second gear (901) and a third gear being respectively fixed to the top and bottom of the first movable shaft, and a fourth gear (902) and a U-shaped plate (904) being respectively fixed to the top and bottom of the second movable shaft; The first gear and the second gear (901) are meshed, and the third gear and the fourth gear (902) are meshed; The bottom of the U-shaped plate (904) is connected in a rolling manner with a rolling roller (905); The discharge side of the guide plate (701) is located at the bottom of the second filter plate (805).

3. The phosphorus recovery device for lithium iron phosphate recovery slag according to claim 1, characterized in that: A top inclined plate (101) and a bottom inclined plate (102) are fixed to the bottom of the discharge hopper (301), and the length of the top inclined plate (101) is shorter than that of the bottom inclined plate (102).

4. A method for recovering phosphorus from lithium iron phosphate recovery slag, using the phosphorus recovery device for lithium iron phosphate recovery slag according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Open the feed pipe on the blast furnace, start the motor of the conveyor belt (2), put the lithium iron phosphate and the reaction material into the screening mechanism (4) and the reaction material adding cylinder (5) respectively, and the material and the reaction material fall onto the conveyor belt (2) and are transported by the conveyor belt (2), and finally enter the blast furnace (1) through the feed pipe. After the material addition is completed, close the feed pipe; Step 2: Use an air pump to evacuate the inner cavity of the blast furnace to a vacuum; Step 3: Heat the mixture in a blast furnace at a temperature of 1300-1600 degrees Celsius for 3-8 hours; Step 4: The gas generated by heating the material is connected to the separation chamber through a pipeline; Step 5: Use a refrigeration device attached to the outside of the separation chamber to reduce the temperature of the separation chamber to 5-30 degrees Celsius. At this time, the phosphorus vapor solidifies to form solid phosphorus. The remaining gas in the separation chamber is pumped away by an air pump to obtain solid phosphorus.

5. The phosphorus recovery method of lithium iron phosphate recovery slag according to claim 4, characterized in that: The reactant in step 1 is carbon or a mixture of carbon and silicon dioxide.

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