Method and device for integrating flash evaporation and lithium extraction

Abstract

The invention discloses a method and a device for integrating flash evaporation and lithium extraction. A flash evaporation and lithium extraction integrated device comprises a flash evaporation motor and a reaction kettle, a graphite bin and a cold fog leaching reactor are sequentially arranged in the reaction kettle from top to bottom, a movable partition plate is arranged between the graphite bin and the cold fog leaching reactor, an electrode transversely penetrating through an inner cavity of the reaction kettle is further arranged in the reaction kettle, and the electrode and the graphite bin are coaxially arranged. The flash motor is electrically connected with the electrode, a cylindrical groove for discharging a high-temperature activated material is formed in the bottom of the graphite bin, a sprayer is arranged on the cold fog leaching reactor, and a reaction kettle upper cover is arranged at the top of the reaction kettle. The invention proposes and realizes that the mixed waste powder is activated in an extremely short time to realize deintercalation of lithium from a spinel crystal structure, the lithium is preferentially extracted through water immersion under mild conditions, meanwhile, ferrophosphorus tailings generated by magnetic separation can be recycled in a system again, and the high-temperature flash steam is also subjected to simple temperature control, so that the energy consumption of the system is reduced. The separation of the fluorocarbon oil and the low-carbon gas is realized.

Description

Technical field:

[0001] The invention relates to the technical field of coordinated disposal of ferrophosphorus tailings and waste lithium manganate, and in particular to an integrated method and device for flash distillation lithium extraction. Background technology:

[0002] Hydrometallurgical recovery of lithium elements from waste lithium iron phosphate has been widely used in industrial production to reduce ecological environmental damage and increase energy strategic metal reserves. However, the low-value ferrophosphorus tailings discharged during the recovery process do not meet the standards for battery-grade lithium iron phosphate battery precursors and are abandoned or piled up in large quantities. Nowadays, the recycling of waste lithium batteries is mainly aimed at large-scale energy storage devices, while waste lithium manganese oxide batteries generated by portable electronic devices, small household appliances and / or electric bicycles have not been taken seriously. As the reserves accumulate over time, they pose a great threat to both the environment and the economy. ZL 202310579184.0 discloses a method for recovering valuable metals from waste lithium cobalt oxide using carbon-containing crude iron phosphate produced after selective lithium extraction from lithium iron phosphate. The waste lithium cobalt oxide is recovered after the carbon-containing crude iron phosphate is prepared into phosphoric acid. The reaction steps of this method require lengthy reaction steps, a large amount of concentrated sulfuric acid and long-term high-temperature calcination to leach up to 97.83% of lithium. Publication No. CN118792507A discloses a method for selectively extracting lithium by sulfation roasting of manganese-containing positive electrode materials of waste lithium batteries. The manganese-containing positive electrode materials of waste lithium batteries are mixed with sulfuric acid and roasted, and more than 99% of lithium is leached from the roasting product. The method requires soaking the manganese-containing positive electrode materials of waste lithium batteries in concentrated sulfuric acid for drying, high-temperature roasting, and high-salt wastewater discharge. The above method greatly reduces the economic and environmental benefits of large-scale industrial recovery of waste lithium manganese oxide, and poses a huge challenge in terms of equipment corrosion and stability. Based on the above analysis, whether the ferrophosphorus tailings discharged from the hydrometallurgical recovery of waste lithium iron phosphate can be effectively disposed of efficiently and greenly, and at the same time, the short-process recovery of waste lithium manganese oxide can be achieved, is of great practical significance.

[0003] Therefore, it is necessary to change the hydrometallurgical recovery system that only focuses on the extraction of high-value lithium, while ignoring the defects of the reuse of ferrophosphorus tailings discharged in the process, and optimize the high-energy consumption and strong corrosion recovery strategy of waste lithium manganese oxide in the traditional activation method. Developing a win-win recovery system for the economy and the environment to solve the problems existing in the current recovery direction and recovery system is of great practical significance to industrial development and social scientific and technological progress. Summary of the invention:

[0004] In order to overcome the above-mentioned problems existing in the prior art, the present invention provides an integrated method and device for flash evaporation lithium extraction. Based on the defects that the ferrophosphorus tailings discharged in the process of hydrometallurgical recovery of waste lithium iron phosphate batteries cannot be directly reused as battery-grade iron phosphate, the recycling and reuse process is complicated, and the recycling of waste lithium manganese oxide has high energy consumption, serious equipment corrosion, and large reagent consumption, the coupling Joule flash evaporation heat treatment technology can realize the thermochemical activation property of mixed waste powder to quickly heat up and cool down. The present invention proposes and realizes the activation of mixed waste powder in a very short time to realize the deintercalation of lithium from the spinel crystal structure, and preferentially extracts lithium through water immersion under mild conditions. At the same time, the ferrophosphorus tailings produced by magnetic separation can be recycled in the system, and the high-temperature flash gas can be separated from fluorocarbon oil and low-carbon gas by simple temperature control. At the same time, the problems of stacking a large amount of low-value ferrophosphorus tailings, low economic efficiency of recycling waste lithium manganese oxide, and emission of three wastes in the recycling process are solved.

[0005] The purpose of the present invention is to provide an integrated device for flash evaporation and lithium extraction, comprising a flash evaporation motor and a reactor, wherein a graphite bin for flash evaporation thermal shock reaction and a cold mist leaching reactor for cold mist leaching are arranged in sequence from top to bottom in the reactor, a movable partition is arranged between the graphite bin and the cold mist leaching reactor, an electrode is also arranged in the reactor to cross the inner cavity of the reactor, the electrode is coaxially arranged with the graphite bin, the flash evaporation motor is electrically connected to the electrode, a cylindrical groove for discharging high-temperature activated material is arranged at the bottom of the graphite bin, a sprayer is arranged on the cold mist leaching reactor, and a reactor cover is arranged on the top of the reactor.

[0006] Preferably, an air inlet, a vacuum air path and an air outlet are provided on the outside of the reactor, and the air inlet, the vacuum air path and the air outlet are all connected to the internal cavity of the reactor. The air inlet and the vacuum air path are arranged between the electrode and the movable partition, and the air outlet is arranged between the upper cover of the reactor and the electrode, and the air outlet is connected to the oil phase collection bottle for collecting high-temperature flash steam.

[0007] Preferably, a lithium-rich liquid filter port is provided at the bottom of the reactor, the bottom of the cold mist leaching reactor is connected to the lithium-rich liquid filter port, and the radius ratio of the cylindrical groove to the cold mist leaching reactor is 1:3.

[0008] Preferably, the flash evaporation motor is provided with a control panel for controlling the flash evaporation thermal shock reaction parameters.

[0009] The present invention also protects a method for integrated flash evaporation lithium extraction, which is implemented by the above-mentioned integrated flash evaporation lithium extraction device, and specifically comprises the following steps:

[0010] S1, mixing pretreatment: mixing ferrophosphorus tailings and waste lithium manganate evenly to obtain mixed waste powder;

[0011] S2, flash thermal shock: the mixed waste powder obtained in step S1 is placed in a graphite bin, the reactor is closed with an upper cover, the gas outlet and the gas inlet are closed, the vacuum air line is opened to evacuate to the first end pressure, the vacuum air line is closed, the gas inlet is opened to fill argon gas to the second end pressure, the gas inlet is closed, the flash motor is started, and the flash current density, flash voltage and flash time are adjusted through the control panel to heat the graphite bin, and the graphite bin transfers heat to the mixed waste powder for flash thermal shock reaction, and high-temperature flash gas and high-temperature activated material are obtained after the reaction is completed, the gas outlet and the gas inlet are opened at the same time, the oil-gas separation temperature is controlled, and the high-temperature flash gas is separated into fluorocarbon oil and low-carbon gas through an oil phase collection bottle placed in a constant temperature cooling tank, and the fluorocarbon oil is returned to the extraction agent production process, and the low-carbon gas is returned to the clean fuel production process;

[0012] S3, cold mist leaching: open the movable partition, rotate the electrode to pour the high temperature activated material obtained in step S2 from the graphite bin into the cold mist leaching reactor, and at the same time open the sprayer and close the movable partition, and negative pressure filter to obtain lithium-rich liquid and iron-manganese-rich mixed slag;

[0013] S4, microwave high-pressure lithium extraction: subjecting the lithium-rich solution obtained in step S3 to microwave high-pressure reaction in a microwave high-pressure reactor, and filtering to obtain lithium carbonate and water;

[0014] S5, magnetic separation: dry the iron-manganese mixed slag obtained in step S3, adjust the field strength and rotation speed, and obtain tailings and MnFe2O4 after magnetic separation; return the tailings to step S1 for repeated use, and return MnFe2O4 to the electrochemical sensor production process.

[0015] Preferably, the ferrophosphorus tailings are leaching tailings from hydrometallurgical recovery of waste lithium iron phosphate battery positive electrode materials, and the main component is iron phosphate; the waste lithium manganese oxide is the scraps in the production process of lithium manganese oxide batteries, coating waste or the electrode material after disassembly, sorting and grinding of waste lithium manganese oxide batteries.

[0016] Preferably, the mass ratio of the ferrophosphorus tailings to the waste lithium manganese oxide in step S1 is 1:0.5 to 1:1.5. More preferably, the mass ratio of the ferrophosphorus tailings to the waste lithium manganese oxide in step S1 is 1:0.7 to 1:1.3.

[0017] Preferably, the specific steps of step S1 are: grind the ferrophosphorus tailings and waste lithium manganate into powder and sieve, then take the two waste materials of the same particle size and place them in a powder mixer according to different mass ratios to spin and roll up and down to fully mix, obtain mixed waste powder, and put it into a graphite bin. More preferably, the spin speed is 20 to 70 rpm, and the up and down rolling is performed once every 5 to 10 seconds of spinning to mix evenly to obtain mixed waste powder.

[0018] Preferably, the volume ratio of the mixed waste powder to the graphite bin in step S2 is 0.20-0.45:1 (i.e. 0.2-0.45 m3 / m 3 ). Further preferably, the volume ratio of the mixed waste powder to the graphite bin is 0.25-0.40:1 (i.e. 0.25-0.40 m 3 / m 3 ).

[0019] Preferably, the first endpoint pressure in step S2 is -0.75 to -0.5 MPa, and the second endpoint pressure is 0.5 to 1.0 MPa; the reaction conditions of the flash thermal shock reaction are: the flash current density is 300 to 400 A / cm 2 , flash voltage 20-30V, reaction time 0.1-0.6s. Further preferably, the first endpoint pressure in step S2 is -0.70-0.55MPa, the second endpoint pressure is 0.6-0.9MPa; the reaction conditions of the flash thermal shock reaction are: flash current density 320-380A / cm 2 , flash voltage 22~28V, reaction time 0.2~0.5s. Control the water bath temperature of the constant temperature cooling tank at 5℃~10℃, separate the fluorocarbon oil trifluorobenzene, and the low-carbon fuel gas is propane and carbon dioxide.

[0020] Preferably, the technical parameters of the sprayer in step S3 are: spray flow rate 0.5-1.5 m / s, spray droplet density 70-170 droplet / cm 2 , spray temperature 10°C to 15°C. Further preferably, the technical parameters of the sprayer in step S3 are: spray flow rate 0.75 to 1.25 m / s, spray droplet density 90 to 150 droplet / cm 2 , spray temperature 11℃~14℃.

[0021] Preferably, the conditions of the microwave high pressure reaction described in step S4 are: microwave power 1400-1900MHz, carbon dioxide pressure 2.0-9.5MPa, magnetic stirring speed 300-550rpm; the conditions of the magnetic separation described in step S5 are: surface field strength 350-410mT, speed 20-30rpm. Further preferably, the conditions of the microwave high pressure reaction described in step S4 are: microwave power 1500-1800MHz, carbon dioxide pressure 3.5-8.0MPa, magnetic stirring speed 350-500rpm; the conditions of the magnetic separation described in step S5 are: surface field strength 360-390mT, speed 22-28rpm.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The present invention adopts an integrated flash evaporation lithium extraction method. In terms of recycling waste lithium manganese oxide, the traditional pyrometallurgical sulfuric acid roasting strategy for recycling waste lithium manganese oxide is changed. The activation time is greatly reduced. A new method for recovering lithium elements by cold mist leaching is adopted. The whole recovery process does not involve strong acid, strong alkali and other experimental reagents, avoiding the traditional method of first calcining to remove residual carbon and residual organic matter in waste lithium manganese oxide, strong acid leaching, strong acid immersion drying and then roasting. In addition to the pollutants carried by the waste lithium manganese oxide itself, no impurities are introduced in the process of the present invention. The only additional use is the low-cost and environmentally friendly deionized water cold mist leaching to recover lithium elements and leach lithium elements.

[0024] 2. In terms of recycling ferrophosphorus tailings, the traditional strategy of recycling ferrophosphorus tailings into phosphoric acid and ferric oxide, as well as the method of purifying and refining battery-grade ferric phosphate through lengthy steps, is changed. The present invention synergistically disposes of ferrophosphorus tailings and waste lithium manganese oxide. The tailings obtained by negative pressure filtration of the solution after microwave high-pressure lithium extraction can be effectively separated into composite oxide manganese ferrite and tailings through simple magnetic separation. The tailings can be recycled to the ferrophosphorus tailings process for repeated utilization, and the composite oxide manganese ferrite is returned to the production of electrochemical sensors.

[0025] 3. The flash gas emitted by flash thermal shock is separated into 1,2,4-trifluorobenzene, methane and propane through oil and gas separation, avoiding the discharge of various fluorine-containing liquid products and various carbon-containing gas products by other thermal treatment methods, reducing the treatment of hazardous wastes emitted by the entire recovery system, and having the advantages of high economy, environmental friendliness, greenness and non-toxicity.

[0026] Therefore, the technical solution proposed in the present invention is particularly suitable for the industrial coordinated disposal of ferrophosphorus tailings and waste lithium manganese oxide batteries to reduce costs, close the solid waste recycling chain and avoid hazardous waste emissions. Description of the drawings:

[0027] Figure 1 A process flow chart of an integrated flash evaporation lithium extraction method and device proposed by the present invention;

[0028] Figure 2 This is a schematic front cross-sectional view of an integrated flash evaporation lithium extraction device proposed in the present invention;

[0029] Figure 3 A schematic side view of an integrated flash evaporation lithium extraction device proposed by the present invention;

[0030] Figure 4 This is a schematic top view of the components of an integrated flash evaporation lithium extraction device proposed in the present invention, wherein a represents the reactor cover, b represents the flash evaporation thermal shock reaction chamber, c represents the movable partition, and d represents the cold mist immersion reactor chamber;

[0031] Figure 5The XRD phase determination result diagram of lithium carbonate and tailings obtained in Example 1;

[0032] Figure 6 The mass spectra of fluorocarbon oil and low carbon fuel gas were obtained for Example 1;

[0033] Explanation of the reference numerals in the accompanying drawings: 1. Flash evaporation motor; 2. Control panel; 3. Lithium-rich liquid filter port; 4. Cold mist immersion reactor; 5. Sprayer; 6. Movable partition; 7. Graphite bin; 8. Reactor; 9. Reactor cover; 10. Electrode; 11. Air inlet; 12. Vacuum air circuit; 13. Air outlet; 14. Constant temperature cooling tank; 15. Oil phase collection bottle. Specific implementation method:

[0034] The following examples are provided to further illustrate the present invention, rather than to limit the present invention.

[0035] Unless otherwise defined, all professional terms used hereinafter have the same meaning as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the experimental materials and reagents herein are conventional commercial products in the art.

[0036] like Figure 2-4 As shown, a flash evaporation lithium extraction integrated device includes a flash evaporation motor 1, a control panel 2, a lithium-rich liquid filter port 3, a cold mist leaching reactor 4, a sprayer 5, a movable partition 6, a graphite bin 7, a reactor 8, a reactor upper cover 9, an electrode 10, an air inlet 11, a vacuum air path 12, an air outlet 13, a constant temperature cooling tank 14 and an oil phase collection bottle 15. The flash evaporation motor 1 is electrically connected to the electrode 10, and the graphite bin 7 for flash evaporation thermal shock reaction and the cold mist leaching reactor 4 for cold mist leaching are arranged in sequence from top to bottom in the reactor 8, and a movable partition 6 is arranged between the graphite bin 7 and the cold mist leaching reactor 4. The electrode 10 is coaxially arranged with the graphite bin 7, and a cylindrical groove is arranged at the bottom of the graphite bin 7; the electrode 10 crosses the reactor 8, and the reactor 8 is provided with a reactor cover 9; the air inlet 11, the vacuum air path 12, and the air outlet 13 are communicated with the internal cavity of the reactor 8, and the air outlet 13 is communicated with the oil phase collection bottle 15, and the oil phase collection bottle 15 is placed in a constant temperature cooling tank 14; a sprayer 5 is arranged on the cold mist leaching reactor 4, and the cold mist leaching reactor 4 is communicated with the lithium-rich liquid filter port 3 at the bottom of the reactor.

[0037] An air inlet 11, a vacuum air path 12 and an air outlet 13 are arranged outside the reactor 8, and the air inlet 11, the vacuum air path 12 and the air outlet 13 are all connected to the internal cavity of the reactor 8. The air inlet 11 and the vacuum air path 12 are arranged between the electrode 10 and the movable partition 6, and the air outlet 13 is arranged between the reactor upper cover 9 and the electrode 10. The air outlet 13 is connected to the oil phase collection bottle 15 for collecting high-temperature flash steam. A control panel 2 for controlling the flash thermal shock reaction parameters is arranged on the flash motor 1.

[0038] In the following preferred embodiments, the radius ratio of the cylindrical groove to the cold mist immersion reactor is 1:3, that is, Figure 4 The radius of the cylindrical groove in b is R, Figure 4 The radius of the cold mist immersion reactor in d is 3R.

[0039] Ferrophosphorus tailings are tailings produced by the hydrometallurgical process industry to recycle waste lithium iron phosphate battery black powder, which contains impurity elements such as lithium, copper, aluminum, fluorine, sulfur, nitrogen and sodium; waste lithium manganese oxide contains impurity metal elements such as copper and aluminum, organic impurities such as graphite, electrolyte, diaphragm and polyvinylidene fluoride.

[0040] Embodiment 1:

[0041] like Figure 1 As shown, a flash evaporation integrated method for lithium extraction comprises the following steps:

[0042] S1. Pretreatment: grind the ferrophosphorus tailings and waste lithium manganese oxide into powder and sieve them, then take the two wastes with the same particle size and place them in a powder mixer at a mass ratio of 1:0.5, spin at a speed of 20rpm, and roll up and down every 5s to obtain mixed waste powder.

[0043] S2, flash thermal shock: the mixed waste powder obtained in step S1 is placed in a graphite bin, the volume ratio of the mixed waste powder to the graphite bin is 0.2:1, the graphite bin is first evacuated to an end pressure of -0.75 MPa, and then filled with argon to an end pressure of 0.5 MPa, and the flash current density is controlled at 300 A / cm 2 , flash evaporation voltage 20V, flash evaporation reaction time 0.1s, flash evaporation thermal shock mixed waste powder, after the reaction is completed, high-temperature flash gas and high-temperature activated material are obtained, the gas outlet and the gas inlet are opened at the same time, the oil and gas separation temperature is controlled, the high-temperature flash gas is passed through the oil phase collection bottle placed in the constant temperature cooling tank, the water bath temperature of the constant temperature cooling tank is controlled at 5°C to separate the fluorocarbon oil trifluorobenzene, low-carbon fuel gas propane and carbon dioxide, trifluorobenzene is returned to the extractant production process, propane and carbon dioxide are returned to the clean fuel production process.

[0044] S3, cold mist infiltration: The high temperature activated material obtained in step S2 is subjected to cold mist infiltration, wherein the spray flow rate is 0.5 m / s and the spray droplet density is 70 droplet / cm2 , the spray temperature is 10℃, and lithium-rich liquid and iron-manganese-rich mixed slag are obtained by filtration.

[0045] S4, microwave high-pressure lithium extraction: The lithium-rich liquid obtained in step S3 is subjected to intensive conversion in a microwave high-pressure reactor, wherein the microwave power is 1400 MHz, the CO2 pressure is 2 MPa, the magnetic stirring speed is 300 rpm, and lithium carbonate and water are obtained by filtration.

[0046] S5, magnetic separation: dry the iron-manganese-rich mixed slag obtained in step S3, adjust the surface field strength to 350mT, and the rotation speed to 20rpm, obtain MnFe2O4 and tailings after magnetic separation, and return the tailings to step S1 for repeated use; return MnFe2O4 to the electrochemical sensor production process.

[0047] Example 2

[0048] A flash evaporation integrated lithium extraction method comprises the following steps:

[0049] S1. Pretreatment: grind the ferrophosphorus tailings and waste lithium manganese oxide into powder and sieve them, then take the two wastes with the same particle size and place them in a powder mixer at a mass ratio of 1:1.5, rotate at a speed of 70rpm, and roll up and down every 10s to obtain mixed waste powder.

[0050] S2, flash thermal shock: the mixed waste powder obtained in step S1 is placed in a graphite bin, the volume ratio of the mixed waste powder to the graphite bin is 0.45:1, the graphite bin is first evacuated to an end pressure of -0.5 MPa, and then filled with argon to an end pressure of 1.0 MPa, and the flash current density is controlled at 400 A / cm 2 The flash voltage is 30V, the flash reaction time is 0.6s, and the mixed waste powder is flash-heat-shocked. After the reaction is completed, high-temperature flash gas and high-temperature activated material are obtained. The gas outlet and the gas inlet are opened at the same time to control the oil and gas separation temperature. The high-temperature flash gas passes through the oil phase collection bottle placed in the constant temperature cooling tank. The water bath temperature of the constant temperature cooling tank is controlled at 10°C to separate the fluorocarbon oil trifluorobenzene, low-carbon fuel gas propane and carbon dioxide. Trifluorobenzene is returned to the extractant production process, and propane and carbon dioxide are returned to the clean fuel production process.

[0051] S3, cold mist infiltration: The high temperature activated material obtained in step S2 is subjected to cold mist infiltration, wherein the spray flow rate is 1.75 m / s and the spray droplet density is 170 droplet / cm 2 , the spray temperature is 15°C, and lithium-rich liquid and iron-manganese-rich mixed slag are obtained by filtration.

[0052] S4, microwave high-pressure lithium extraction: The lithium-rich liquid obtained in step S3 is subjected to intensive conversion in a microwave high-pressure reactor, wherein the microwave power is 1900 MHz, the CO2 pressure is 9.5 MPa, the magnetic stirring speed is 550 rpm, and lithium carbonate and water are obtained by filtration.

[0053] S5, magnetic separation: dry the iron-manganese-rich mixed slag obtained in step S3, adjust the surface field strength to 400mT, and the rotation speed to 30rpm, obtain MnFe2O4 and tailings after magnetic separation, and return the tailings to step S1 for repeated use; return MnFe2O4 to the electrochemical sensor production process.

[0054] Example 3

[0055] A flash evaporation integrated lithium extraction method comprises the following steps:

[0056] S1. Pretreatment: grind the ferrophosphorus tailings and waste lithium manganese oxide into powder and sieve them, then take the two wastes with the same particle size and place them in a powder mixer at a mass ratio of 1:0.7, rotate at a speed of 30rpm, and roll up and down every 6s to obtain mixed waste powder.

[0057] S2, flash thermal shock: the mixed waste powder obtained in step S1 is placed in a graphite bin, the volume ratio of the mixed waste powder to the graphite bin is 0.25:1, the graphite bin is first evacuated to an end pressure of -0.7 MPa, and then filled with argon to an end pressure of 0.6 MPa, and the flash current density is controlled at 320 A / cm 2 The flash voltage is 22V, the flash reaction time is 0.2s, and the mixed waste powder is flash-heat-shocked. After the reaction is completed, high-temperature flash gas and high-temperature activated material are obtained. The gas outlet and the gas inlet are opened at the same time to control the oil and gas separation temperature. The high-temperature flash gas passes through the oil phase collection bottle placed in the constant temperature cooling tank. The water bath temperature of the constant temperature cooling tank is controlled at 6°C to separate the fluorocarbon oil trifluorobenzene, low-carbon fuel gas propane and carbon dioxide. Trifluorobenzene is returned to the extractant production process, and propane and carbon dioxide are returned to the clean fuel production process.

[0058] S3, cold mist soaking: The high temperature activated material obtained in step S2 is subjected to cold mist soaking, wherein the spray flow rate is 0.75m / s, and the spray droplet density is 90droplet / cm 2 , the spray temperature is 11°C, and lithium-rich liquid and iron-manganese-rich mixed slag are obtained by filtration.

[0059] S4, microwave high-pressure lithium extraction: The lithium-rich liquid obtained in step S3 is subjected to intensive conversion in a microwave high-pressure reactor, wherein the microwave power is 1500 MHz, the CO2 pressure is 3.5 MPa, the magnetic stirring speed is 350 rpm, and lithium carbonate and water are obtained by filtration.

[0060] S5, magnetic separation: dry the iron-manganese-rich mixed slag obtained in step S3, adjust the surface field strength to 360mT, and the rotation speed to 22rpm, obtain MnFe2O4 and tailings after magnetic separation, and return the tailings to step S1 for repeated use; return MnFe2O4 to the electrochemical sensor production process.

[0061] Example 4

[0062] A flash evaporation integrated lithium extraction method comprises the following steps:

[0063] S1. Pretreatment: grind the ferrophosphorus tailings and waste lithium manganese oxide into powder and sieve them, then take the two wastes with the same particle size and place them in a powder mixer at a mass ratio of 1:1.3, rotate at a speed of 60rpm, and roll up and down every 9s to obtain mixed waste powder.

[0064] S2, flash thermal shock: the mixed waste powder obtained in step S1 is placed in a graphite bin, the volume ratio of the mixed waste powder to the graphite bin is 0.4:1, the graphite bin is first evacuated to an end pressure of -0.55 MPa, and then filled with argon to an end pressure of 0.9 MPa, and the flash current density is controlled at 380 A / cm 2 The flash voltage is 28V, the flash reaction time is 0.5s, and the mixed waste powder is flash-heat-shocked. After the reaction is completed, high-temperature flash gas and high-temperature activated material are obtained. The gas outlet and the gas inlet are opened at the same time to control the oil and gas separation temperature. The high-temperature flash gas passes through the oil phase collection bottle placed in the constant temperature cooling tank. The water bath temperature of the constant temperature cooling tank is controlled at 9°C to separate the fluorocarbon oil trifluorobenzene, low-carbon fuel gas propane and carbon dioxide. Trifluorobenzene is returned to the extractant production process, and propane and carbon dioxide are returned to the clean fuel production process.

[0065] S3, cold mist infiltration: The high temperature activated material obtained in step S2 is subjected to cold mist infiltration, wherein the spray flow rate is 1.5 m / s and the spray droplet density is 150 droplet / cm 2 , the spray temperature is 14°C, and lithium-rich liquid and iron-manganese-rich mixed slag are obtained by filtration.

[0066] S4, microwave high-pressure lithium extraction: The lithium-rich liquid obtained in step S3 is subjected to intensive conversion in a microwave high-pressure reactor, wherein the microwave power is 1800 MHz, the CO2 pressure is 8 MPa, the magnetic stirring speed is 500 rpm, and lithium carbonate and water are obtained by filtration.

[0067] S5, magnetic separation: dry the iron-manganese-rich mixed slag obtained in step S3, adjust the surface field strength to 390mT, and the rotation speed to 28rpm, obtain MnFe2O4 and tailings after magnetic separation, and return the tailings to step S1 for repeated use; return MnFe2O4 to the electrochemical sensor production process.

[0068] Example 5

[0069] A flash evaporation integrated lithium extraction method comprises the following steps:

[0070] S1. Pretreatment: grind the ferrophosphorus tailings and waste lithium manganese oxide into powder and sieve them, then take the two wastes with the same particle size and place them in a powder mixer at a mass ratio of 1:0.9, rotate at a speed of 40 rpm, and roll up and down every 7 seconds to obtain mixed waste powder;

[0071] S2, flash thermal shock: the mixed waste powder obtained in step (1) is placed in a graphite bin, the volume ratio of the mixed waste powder to the graphite bin is 0.3:1, the graphite bin is first evacuated to an end pressure of -0.65 MPa, and then filled with argon to an end pressure of 0.7 MPa, and the flash current density is controlled at 340 A / cm 2 The flash voltage is 24V, the flash reaction time is 0.3s, and the mixed waste powder is flash-heat-shocked. After the reaction is completed, high-temperature flash gas and high-temperature activated material are obtained. The gas outlet and the gas inlet are opened at the same time to control the oil and gas separation temperature. The high-temperature flash gas passes through the oil phase collection bottle placed in the constant temperature cooling tank. The water bath temperature of the constant temperature cooling tank is controlled at 7°C to separate the fluorocarbon oil trifluorobenzene, low-carbon fuel gas propane and carbon dioxide. Trifluorobenzene is returned to the extractant production process, and propane and carbon dioxide are returned to the clean fuel production process.

[0072] S3, cold mist separation: The activated material obtained in step S2 is subjected to cold mist separation, wherein the spray flow rate is 1 m / s and the spray droplet density is 110 droplet / cm 2 , the spray temperature is 12°C, and lithium-rich liquid and iron-manganese-rich mixed slag are obtained by filtration.

[0073] S4, microwave high-pressure lithium extraction: The lithium-rich liquid obtained in step S3 is subjected to intensive conversion in a microwave high-pressure reactor, wherein the microwave power is 1600 MHz, the CO2 pressure is 5 MPa, the magnetic stirring speed is 400 rpm, and lithium carbonate and water are obtained by filtration.

[0074] S5, magnetic separation: dry the iron-manganese-rich mixed slag obtained in step S3, adjust the surface field strength to 370mT, and the rotation speed to 24rpm, obtain MnFe2O4 and tailings after magnetic separation, and return the tailings to step S1 for repeated use; return MnFe2O4 to the electrochemical sensor production process.

[0075] Example 6

[0076] A flash evaporation integrated lithium extraction method comprises the following steps:

[0077] S1. Pretreatment: grind the ferrophosphorus tailings and waste lithium manganese oxide into powder and sieve them, then take the two wastes with the same particle size and place them in a powder mixer at a mass ratio of 1:1.1, rotate at a speed of 50rpm, and roll up and down every 8s to obtain mixed waste powder.

[0078] S2, flash thermal shock: the mixed waste powder obtained in step S1 is placed in a graphite bin, the volume ratio of the mixed waste powder to the graphite bin is 0.35:1, the graphite bin is first evacuated to an end pressure of -0.6 MPa, and then filled with argon to an end pressure of 0.9 MPa, and the flash current density is controlled at 360 A / cm 2 The flash voltage is 26V, the flash reaction time is 0.4s, and the mixed waste powder is flash-heat-shocked. After the reaction is completed, high-temperature flash gas and high-temperature activated material are obtained. The gas outlet and the gas inlet are opened at the same time to control the oil and gas separation temperature. The high-temperature flash gas passes through the oil phase collection bottle placed in the constant temperature cooling tank. The water bath temperature of the constant temperature cooling tank is controlled at 8°C to separate the fluorocarbon oil trifluorobenzene, low-carbon fuel gas propane and carbon dioxide. Trifluorobenzene is returned to the extractant production process, and propane and carbon dioxide are returned to the clean fuel production process.

[0079] S3, cold mist separation: The activated material obtained in step S2 is subjected to cold mist separation, wherein the spray flow rate is 1.25 m / s and the spray droplet density is 130 droplet / cm 2 , the spray temperature is 13°C, and lithium-rich liquid and iron-manganese-rich mixed slag are obtained by filtration.

[0080] S4, microwave high-pressure lithium extraction: The lithium-rich liquid obtained in step S3 is subjected to intensive conversion in a microwave high-pressure reactor, wherein the microwave power is 1700 MHz, the CO2 pressure is 6.5 MPa, the magnetic stirring speed is 450 rpm, and lithium carbonate and water are obtained by filtration.

[0081] S5, magnetic separation: dry the iron-manganese mixed slag obtained in step S3, adjust the surface field strength to 380mT, and the rotation speed to 26rpm, obtain MnFe2O4 and tailings after magnetic separation, and return the tailings to step S1 for repeated use; return MnFe2O4 to the electrochemical sensor production process.

[0082] Comparative Example 1

[0083] Refer to Example 2, the difference is that the flash thermal shock process is not vacuumed first, and argon is directly filled to the end pressure of 1.0 MPa. The rest of the process and parameters are the same as Example 2.

[0084] Since the flash thermal shock process in Comparative Example 1 was not pre-vacuumed, the mixed waste powder contained a higher oxygen content, resulting in the oxidation of residual carbon into carbon dioxide or carbon monoxide, the low-carbon fuel gas content in the flash gas was reduced, the carbon emissions increased, the partial oxidation stability of the graphite bin was reduced, and clean high-value conversion could not be achieved.

[0085] Comparative Example 2

[0086] Refer to Example 2, the difference is that only vacuum is applied without filling with argon gas, and the rest of the process and parameters are the same as those in Example 2.

[0087] Since argon gas was not introduced in Example 2, the mixed waste powder lost its protective atmosphere, resulting in tip discharge of metal elements when current passed through, generating local high heat and poor uniformity of the activated product. The efficient recovery of lithium elements by ferrophosphorus tailings and waste lithium manganese oxide could not be achieved.

[0088] Comparative Example 3

[0089] Refer to Example 2, except that no ferrophosphorus tailings were added, and the rest of the process and parameters were the same as those in Example 2.

[0090] Since no ferrophosphorus tailings were added in Example 2, a large amount of lithium element was lost in the waste lithium manganese oxide in the form of gas at high temperature, the lithium leaching rate was extremely low, and the manganese element existed in the slag as a mixture of manganese oxide and manganese dioxide, which required lengthy steps to separate and return to industrial use, and the purpose of efficient and economical recovery was not achieved.

[0091] The lithium leaching rate, fluorocarbon oil and residual amount of miscellaneous elements in Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 1:

[0092] Table 1

[0093]

[0094] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An integrated device for flash evaporation and lithium extraction, characterized in that The invention comprises a flash motor (1) and a reactor (8), wherein a graphite bin (7) for flash thermal shock reaction and a cold mist extraction reactor (4) for cold mist extraction are arranged in sequence from top to bottom in the reactor (8), a movable partition (6) is arranged between the graphite bin (7) and the cold mist extraction reactor (4), an electrode (10) is also arranged in the reactor (8) to cross the inner cavity of the reactor (8), the electrode (10) is arranged coaxially with the graphite bin (7), the flash motor (1) is electrically connected to the electrode (10), a cylindrical groove for discharging high-temperature activated materials is arranged at the bottom of the graphite bin (7), a sprayer (5) is arranged on the cold mist extraction reactor (4), and a reactor cover (9) is arranged on the top of the reactor (8).

2. The integrated flash evaporation lithium extraction device according to claim 1, characterized in that: The outside of the reactor (8) is provided with an air inlet (11), a vacuum air path (12) and an air outlet (13); the air inlet (11), the vacuum air path (12) and the air outlet (13) are all connected to the internal cavity of the reactor (8); the air inlet (11) and the vacuum air path (12) are arranged between the electrode (10) and the movable partition (6); the air outlet (13) is arranged between the reactor upper cover (9) and the electrode (10); and the air outlet (13) is connected to an oil phase collection bottle (15) for collecting high-temperature flash steam.

3. The integrated flash evaporation lithium extraction device according to claim 1, characterized in that: The bottom of the reactor (8) is provided with a lithium-rich liquid filter port (3), the bottom of the cold mist leaching reactor (4) is connected to the lithium-rich liquid filter port (3), and the radius ratio of the cylindrical groove to the cold mist leaching reactor (4) is 1:

3.

4. The integrated flash evaporation lithium extraction device according to claim 1, characterized in that: The flash evaporation motor (1) is provided with a control panel (2) for controlling the flash evaporation thermal shock reaction parameters.

5. A flash evaporation integrated method for lithium extraction, characterized in that: The method is implemented by the integrated flash evaporation lithium extraction device according to any one of claims 1 to 4, and specifically comprises the following steps: S1, mixing pretreatment: mixing ferrophosphorus tailings and waste lithium manganate evenly to obtain mixed waste powder; S2, flash thermal shock: the mixed waste powder obtained in step S1 is placed in a graphite bin, the reactor (8) is closed with a reactor cover (9), the gas outlet (13) and the gas inlet (11) are closed, the vacuum air path (12) is opened, and the vacuum is evacuated to a first end point pressure, the vacuum air path (12) is closed, the gas inlet (11) is opened, argon gas is filled to a second end point pressure, the gas inlet (11) is closed, the flash motor (1) is started, and the flash current density and the flash current are adjusted through the control panel (2). The graphite bin (7) is heated by the pressure and flash time, and the graphite bin (7) transfers heat to the mixed waste powder to perform a flash thermal shock reaction. After the reaction is completed, high-temperature flash gas and high-temperature activated material are obtained. The gas outlet (13) and the gas inlet (11) are opened at the same time to control the oil and gas separation temperature. The high-temperature flash gas passes through an oil phase collection bottle (15) placed in a constant temperature cooling tank (14) to separate fluorocarbon oil and low-carbon gas. The fluorocarbon oil is returned to the extraction agent production process, and the low-carbon fuel gas is returned to the clean fuel production process. S3, cold mist leaching: opening the movable partition (6), rotating the electrode (10) to pour the high temperature activated material obtained in step S2 from the graphite bin (7) into the cold mist leaching reactor (4), and at the same time opening the sprayer (5) and closing the movable partition (6), and negative pressure filtering to obtain lithium-rich liquid and iron-manganese-rich mixed slag; S4, microwave high-pressure lithium extraction: subjecting the lithium-rich solution obtained in step S3 to microwave high-pressure reaction in a microwave high-pressure reactor, and filtering to obtain lithium carbonate and water; S5, magnetic separation: dry the iron-manganese mixed slag obtained in step S3, adjust the field strength and rotation speed, and obtain tailings and MnFe2O4 after magnetic separation; return the tailings to step S1 for repeated use, and return MnFe2O4 to the electrochemical sensor production process.

6. The method according to claim 5, characterized in that The mass ratio of the ferrophosphorus tailings to the waste lithium manganese oxide in step S1 is 1:0.5 to 1:1.

5.

7. The method according to claim 5, characterized in that The volume ratio of the mixed waste powder to the graphite bin (7) in step S2 is 0.20-0.45:

1.

8. The method according to claim 5 or 7, characterized in that: The first endpoint pressure in step S2 is -0.75 to -0.5 MPa, and the second endpoint pressure is 0.5 to 1.0 MPa; the reaction conditions of the flash thermal shock reaction are: the flash current density is 300 to 400 A / cm 2 , flash voltage 20~30V, reaction time 0.1~0.6s.

9. The method according to claim 5, characterized in that The technical parameters of the sprayer in step S3 are: spray flow rate 0.5-1.5 m / s, spray droplet density 70-170 droplet / cm 2 , spray temperature 10℃~15℃.

10. The method according to claim 5, characterized in that The conditions for the microwave high-pressure reaction in step S4 are: microwave power 1400-1900 MHz, carbon dioxide pressure 2.0-9.5 MPa, and magnetic stirring speed 300-550 rpm; the conditions for the magnetic separation in step S5 are: surface field strength 350-410 mT, and speed 20-30 rpm.

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