Recycling method of lithium-containing industrial waste

Abstract

The invention provides a recovery method of lithium-containing industrial waste. The recycling method of the lithium-containing industrial waste comprises the following steps: fully mixing the lithium-containing industrial waste, calcium carbonate, calcium sulfate and potassium sulfate to form a uniform mixed material; pressing the mixed material into a cake-shaped mixed material; roasting the cake-shaped mixed material to obtain a transformed material; the transformed material is ground into transformed material powder; mixing the transformed material powder with dilute sulphuric acid with the concentration of 1%, stirring and leaching, and filtering and separating to obtain leaching brine; extracting, separating and leaching heavy metals in the brine to obtain raffinate; adding a fluorine removal agent and a flocculating agent into the raffinate, fully reacting, and filtering to obtain a fluorine removal solution and fluorine removal residues; the defluorination liquid crystallization adopts a freezing crystallization method to remove potassium and sodium salts, and a lithium-containing solution is obtained through separation. In the invention, the problem of high price of potassium sulfate in sulfate is reduced, the lithium recovery rate is improved, and the recovery difficulty is reduced, so that the method is suitable for the characteristics and chemical composition structure of the lithium-containing industrial waste.

Description

Technical Field

[0001] The present application relates to the technical field of recycling lithium-containing waste, and in particular to a method for recycling lithium-containing industrial waste. Background Art

[0002] As the new energy vehicle industry enters its golden development period, the power lithium battery industry is experiencing explosive growth, the demand for lithium carbonate is surging, and a large amount of lithium electrolysis waste is generated. If these lithium electrolysis wastes are used reasonably, it will help alleviate the pressure on lithium use brought by the new energy industry. Since the structure and performance of industrial waste are different from those of commonly used lithium mica and spodumene, the melting point and lithium salt compound composition of lithium-containing industrial waste are different from those of lithium mica. Lithium-containing industrial waste does not exist in the form of ore, so the commonly used ore lithium extraction method is not suitable for lithium-containing industrial waste, and the recovery of lithium-containing industrial waste and brine purification are relatively difficult. Summary of the invention

[0003] The present application provides a rainproof device, a cabinet assembly, an energy storage device and a system that are helpful in reducing the possibility of rainwater entering the interior of a cabinet.

[0004] In a first aspect, an embodiment of the present application provides a method for recycling lithium-containing industrial waste, the method for recycling lithium-containing industrial waste comprising:

[0005] The lithium-containing industrial waste, calcium carbonate, calcium sulfate and potassium sulfate are fully mixed to form a uniform mixture;

[0006] Pressing the mixture into a cake-shaped mixture;

[0007] roasting the cake-shaped mixed material to obtain a transition material;

[0008] Grinding the transition material into transition material powder;

[0009] The transformation material powder is mixed with 1% dilute sulfuric acid, stirred and leached, and filtered and separated to obtain leaching brine;

[0010] Extract and separate the heavy metals in the leached brine to obtain a raffinate;

[0011] Adding a defluorinating agent and a flocculant to the raffinate, filtering after sufficient reaction to obtain a defluorinating liquid and a defluorinating residue;

[0012] The defluorination liquid crystallization adopts a freezing crystallization method to remove potassium and sodium salts, and separates to obtain a lithium-containing solution.

[0013] According to the first aspect, in a possible implementation manner, the lithium-containing industrial waste, the calcium carbonate, the calcium sulfate, and the potassium sulfate are mixed in a mass percentage of 6:1:1:1.

[0014] According to the first aspect, in a possible implementation, the step of extracting and separating the heavy metals in the leached brine to obtain a raffinate comprises:

[0015] The leached brine is used as a raw material, and a p204 / 4pc co-extraction system is used as an extraction organic phase. The leached brine raw material is subjected to multi-stage countercurrent extraction under preset conditions; heavy metal ions in the leached brine enter the organic phase and are separated to obtain a lithium-containing raffinate.

[0016] According to the first aspect, in a possible implementation manner, the preset condition includes:

[0017] The ratio of the leaching brine to the organic phase is 1, the pH of the leaching brine is adjusted to 3-6, and the brine is shaken at a speed of 200 r / min for 30 minutes.

[0018] According to the first aspect, in a possible implementation, the concentration of p204 is 0.5 mol / L, and the concentration of 4pc is 1.5 mol / L.

[0019] According to the first aspect, in a possible implementation, the defluorinating agent is aluminum sulfate with a concentration of 10%-15%, and the amount of the defluorinating agent added is 1%-3% of the volume of the raffinate.

[0020] According to the first aspect, in a possible implementation, the flocculant is PAM with a concentration of 1‰-2‰, and the amount of the flocculant added is 3%-5% of the volume of the raffinate.

[0021] According to the first aspect, in a possible implementation, the cake-shaped mixture is calcined at a temperature of 900-1000° C. and for a time of 0.5-1 h.

[0022] According to the first aspect, in a possible implementation, the transition material is ground to a size of 80 mesh or more.

[0023] According to the first aspect, in a possible implementation manner, the molding pressure of the mixed material pressed cake is 50-100Pa.

[0024] The method for recovering lithium-containing industrial waste provided in the present application adds calcium carbonate and sulfate at the same time in a certain proportion, which can reduce the problem of high price of potassium sulfate in sulfate, avoid excessive addition of limestone in the calcium carbonate method, low lithium recovery rate and difficulty in recovery, and can also avoid acid pollution and equipment corrosion involved in the sulfuric acid method. The leaching rate is greatly improved and is suitable for the characteristics and chemical composition structure of lithium-containing industrial waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 is a schematic diagram of a process flow diagram of a method for recycling lithium-containing industrial waste in one embodiment of the present application;

[0027] Figure 2 It is a comparison chart of test data of the first to fifth embodiments of the present application. DETAILED DESCRIPTION

[0028] The words "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that may provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0029] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of the present invention.

[0031] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0032] As shown in the figure, in one embodiment of the present application, the method for recycling lithium-containing industrial waste includes:

[0033] Step S10, fully mixing the lithium-containing industrial waste, calcium carbonate, calcium sulfate and potassium sulfate to form a uniform mixture;

[0034] The lithium-containing industrial waste is mixed with specific additives (calcium carbonate, calcium sulfate and potassium sulfate) to form a homogenous mixture. The purpose of this mixing is to facilitate the subsequent roasting transformation process, so that the lithium element can be released more effectively from the waste and facilitate subsequent extraction and purification.

[0035] During the mixing process, it is necessary to ensure that all raw materials are fully stirred to avoid local overheating or uneven sintering during the subsequent roasting process, and to improve the release efficiency and recovery rate of lithium elements. To achieve this goal, a mechanical stirrer or mixing equipment is usually required, and the stirring time and speed are strictly controlled to ensure the uniformity and consistency of the mixture.

[0036] In addition, the humidity and particle size of the raw materials are also important factors affecting the mixing effect and the subsequent roasting process. If the raw materials are too wet or the particles are too large, it may cause uneven mixing or poor roasting effect. Therefore, before mixing, the raw materials need to be properly dried and crushed to ensure that they meet the process requirements.

[0037] Calcium carbonate mainly plays the role of slag removal, converting aluminum, silicon, etc. into water-insoluble compounds. Adding calcium carbonate in a fixed proportion avoids the situation where too much slag is added alone. Mixing a small amount of potassium sulfate into calcium sulfate can increase the conversion rate of the roasting process. Calcium sulfate alone cannot convert most of the lithium in the waste into soluble lithium, which improves the problem of too low conversion rate when using calcium sulfate alone and the problem of too high price of potassium sulfate when using alone.

[0038] The raw materials such as calcium carbonate and calcium sulfate used in the method for recovering lithium-containing industrial waste of the present invention are all cheap and easily available raw materials. Potassium sulfate can also be recovered and recycled from brine leached from industrial waste, which is economical and environmentally friendly.

[0039] The lithium-containing industrial waste, the calcium carbonate, the calcium sulfate and the potassium sulfate are mixed in a mass percentage of 6:1:1:1. It is worth noting that this ratio is not absolutely fixed. In practical applications, the ratio of each raw material can be appropriately adjusted according to the specific composition and properties of the lithium-containing industrial waste, as well as the desired lithium recovery rate and economic benefits. For example, the proportion of lithium-containing industrial waste in the mixture can be appropriately reduced to improve the conversion rate.

[0040] Step S20, pressing the mixture into a cake-shaped mixture;

[0041] The main purpose of pressing the mixture into a cake shape is to improve the heat transfer efficiency and uniformity of the mixture during the roasting process. By pressing the mixture into a compact cake shape, the heat loss and temperature unevenness caused by the large gaps between particles during the roasting process can be reduced. The compact cake structure helps control the rate of heat diffusion, so that the chemical reaction during the roasting process can be carried out under more uniform temperature conditions, thereby improving the controllability and efficiency of the reaction. By controlling the molding pressure and the density of the cake, the sintering problem caused by excessive temperature during the roasting process can be avoided, protecting the lithium element and other valuable components.

[0042] Pressing into cakes can also reduce dust generated by grinding the mixing materials, reduce pollution to the environment, and make subsequent processing and collection easier.

[0043] During the pressing process, it is necessary to select appropriate molding pressure and mold to ensure that the cake-shaped mixture has sufficient strength and stability. The molding pressure of the mixture cake is 50-100 Pa.

[0044] Step S30, roasting the cake-shaped mixed material to obtain a transition material;

[0045] The mixture pressed into a cake shape is roasted at high temperature to release lithium from the waste and convert it into a form that is easier to extract, namely the transformation material. In this process, the control of roasting temperature and roasting time is crucial, as they not only affect the release efficiency of lithium, but also directly affect whether the waste will sinter and burn.

[0046] The roasting temperature can be set at 900-1000°C, which is high enough to trigger chemical reactions in the mixture, releasing lithium from the waste and converting it into the desired compound. However, too high a temperature may cause the waste to over-sinter and form a hard sintered body, which will not only reduce the recovery rate of lithium, but also increase the difficulty of subsequent extraction and purification. Therefore, choosing the appropriate roasting temperature is the key to ensure a smooth recovery process.

[0047] The roasting time can be controlled between 0.5 and 1 hour. This time range is determined by the composition of the mixture, particle size, pressing density, and the desired lithium recovery rate. Sufficient roasting time can ensure that the reaction is fully carried out and release as much lithium as possible. However, too long roasting time will also increase the risk of sintering and may lead to increased energy consumption. Therefore, the roasting time should be shortened as much as possible while ensuring that the reaction is fully carried out.

[0048] In order to ensure that lithium-containing industrial waste does not sinter during the roasting process, in addition to controlling the roasting temperature and time, other measures can be taken. For example, the mixed material should be fully dried before roasting to reduce its moisture content; during the roasting process, a proper furnace atmosphere should be maintained, such as introducing a proper amount of air or inert gas; and appropriate roasting equipment and process parameters should be used.

[0049] Step S40, grinding the transition material into transition material powder;

[0050] The calcined transition material is further ground into powder. The particle size of the transition material is reduced to increase the leaching rate, that is, the efficiency of lithium dissolving from the transition material into the solvent.

[0051] Specifically, if the particle size of the transformation material is too large, then its specific surface area (i.e., the surface area per unit mass of the material) will be relatively small. During the leaching process, the contact area between the solvent and the material is limited, which makes it difficult for the lithium element to fully dissolve into the solvent, thereby reducing the leaching rate. On the contrary, when the transformation material is ground to more than 80 mesh, its particle size is significantly reduced and the specific surface area is increased, allowing the solvent to more fully contact the material, thereby improving the leaching efficiency of the lithium element.

[0052] In addition, the transformation material powder ground to more than 80 mesh also has better fluidity and uniformity, which is conducive to the smooth progress of subsequent processing steps. For example, during the leaching process, the powdered material can be more evenly distributed in the solvent, reducing local concentration differences and improving the stability and controllability of the leaching process.

[0053] During the grinding process, it is necessary to select appropriate grinding equipment and process parameters to ensure that the transition material can be evenly ground to the required particle size. Common grinding equipment includes ball mills, vibration mills, airflow mills, etc. They each have their own advantages and disadvantages and need to be selected according to specific circumstances. At the same time, it is also necessary to pay attention to controlling factors such as grinding time, type and amount of grinding media to avoid adverse effects on the properties of the transition material.

[0054] Step S50, mixing, stirring and leaching the transformation material powder and 1% dilute sulfuric acid, and filtering and separating to obtain leaching brine;

[0055] The ground transformation material powder is mixed, stirred and leached with dilute sulfuric acid to extract the lithium element.

[0056] The transformation material powder ground to more than 80 meshes is mixed with 1% dilute sulfuric acid in a certain proportion. This proportion is usually determined according to the lithium content in the transformation material, the solubility of sulfuric acid and the needs of subsequent treatment. The purpose of mixing is to allow the dilute sulfuric acid to fully contact the surface of the transformation material powder, providing conditions for the subsequent leaching process.

[0057] After mixing, the mixture needs to be fully stirred. The purpose of stirring is to evenly distribute the dilute sulfuric acid in the transition material powder, thereby increasing the contact area between the sulfuric acid and the powder and improving the leaching efficiency. The stirring time and speed need to be adjusted according to the specific situation to ensure that the leaching reaction can proceed fully, while avoiding the negative effects that may be caused by excessive stirring, such as increased energy consumption or excessive wear of powder particles.

[0058] While stirring, dilute sulfuric acid reacts chemically with the lithium element in the transition material powder, transferring lithium from the solid phase to the liquid phase to form a lithium-containing leaching brine. This process is called leaching. The efficiency of leaching is affected by many factors, including the concentration of sulfuric acid (although weakly acidic dilute sulfuric acid is used in this application, its concentration still needs to be controlled to optimize the leaching effect), reaction temperature, stirring intensity, and the particle size of the transition material powder. By optimizing these conditions, the leaching rate of lithium can be maximized.

[0059] After leaching is completed, the leached brine needs to be separated from the unreacted transformation material powder by filtering. The purpose of filtration is to remove solid impurities and obtain pure leached brine for subsequent lithium extraction and purification steps. During the filtration process, the filtration speed needs to be controlled to avoid the filter cake being too thick, resulting in difficulty in filtration or turbidity in the filtrate.

[0060] The leached brine obtained after filtration is rich in lithium and is an important raw material for the subsequent extraction and purification process.

[0061] Compared with the conventional acid leaching process for industrial waste, the dilute sulfuric acid used in this application is weakly acidic, which makes the process have significant advantages in terms of environmental friendliness and equipment protection. Weakly acidic solutions are not easy to pollute the environment, and also reduce the risk of corrosion to leaching equipment, thereby extending the service life of the equipment and reducing maintenance costs. It is conducive to industrial production.

[0062] Step S60, extracting and separating the heavy metals in the leached brine to obtain a raffinate;

[0063] The step of extracting and separating the heavy metals in the leached brine to obtain a raffinate comprises:

[0064] The leached brine is used as a raw material, and a p204 / 4pc co-extraction system is used as an extraction organic phase. The leached brine raw material is subjected to multi-stage countercurrent extraction under preset conditions; heavy metal ions in the leached brine enter the organic phase and are separated to obtain a lithium-containing raffinate.

[0065] This step uses the P204 / 4pc synergistic extraction system as the organic phase for extraction. P204 (di(2-ethylhexyl)phosphoric acid) is used as the main extractant. P204 has the ability to extract a variety of metal ions, but its extraction ability for lithium ions is relatively weak. This characteristic enables P204 to preferentially bind to heavy metal ions during the extraction process, while leaving lithium ions in the aqueous phase. The addition of 4pc is intended to enhance the extraction effect of P204, especially the selective extraction of heavy metal ions. The design of this synergistic extraction system enables heavy metal ions to be more effectively transferred to the organic phase during the extraction process, while lithium ions are relatively retained in the aqueous phase.

[0066] The preset conditions include:

[0067] Phase ratio (O / A ratio): The ratio (volume ratio) of leaching brine to organic phase is set to 1, that is, each volume of organic phase is in contact with an equal volume of leaching brine. The selection of this ratio is based on experimental optimization or industrial experience, aiming to balance extraction efficiency and economic benefits.

[0068] pH adjustment: The pH value of the leaching brine is adjusted to 3-6. This range is conducive to the combination of heavy metal ions with the p204 / 4pc synergistic extraction system, while reducing the adverse effects on lithium ion extraction. The pH value is usually adjusted by adding an appropriate amount of acid or alkali.

[0069] Oscillation speed and time: Oscillate at a speed of 200r / min for 30min. The purpose of oscillation is to promote full contact and mixing between the leaching brine and the organic phase, thereby improving the extraction efficiency. The selection of this condition is also based on experimental optimization or industrial experience.

[0070] Concentrations of p204 and 4pc: The concentration of p204 is 0.5mol / L, and the concentration of 4pc is 1.5mol / L. These two concentrations are chosen to ensure that the synergistic extraction system has sufficient extraction capacity and selectivity. At the same time, the use of sulfonated kerosene as a diluent helps to adjust the viscosity and density of the extraction system and further improve the extraction effect.

[0071] Extraction stages: Five-stage countercurrent extraction is adopted. Multi-stage countercurrent extraction technology can make full use of the extractant and improve the extraction efficiency and purity. In each stage, heavy metal ions are gradually transferred from the aqueous phase to the organic phase, while most of the lithium ions are retained in the aqueous phase.

[0072] Under the preset conditions, the leached brine and the p204 / 4pc co-extraction system are subjected to five-stage countercurrent extraction. As the extraction proceeds, heavy metal ions are gradually extracted into the organic phase, while lithium ions are enriched in the aqueous phase to form a lithium-containing raffinate. The successful implementation of this step provides high-quality raw materials for the subsequent extraction and purification of lithium elements.

[0073] The present application separates heavy metals from the solution through an extraction process, which can reduce the harm of the leachate to the environment. The extraction rate of the extraction system for heavy metals such as nickel, copper, and iron reaches more than 98%, with extremely high extraction efficiency. In addition, the extractant can be recycled, which reduces production costs and improves economic benefits.

[0074] Step S70, adding a defluorinating agent and a flocculant to the raffinate, filtering after sufficient reaction to obtain a defluorinating liquid and a defluorinating residue;

[0075] In this step, aluminum sulfate (Al2(SO4)3) with a concentration of 10%-15% is used as a defluoridation agent. Aluminum sulfate is hydrolyzed in water to produce aluminum ions (Al 3+ ), these aluminum ions and fluoride ions (F - ) combines with other organic compounds to form insoluble aluminum fluoride (AlF3) precipitate, thus effectively removing fluoride ions from the solution.

[0076] The amount of aluminum sulfate added is 1%-3% of the volume of the raffinate, in order to ensure that fluoride ions can be fully removed while avoiding the increase in costs and possible negative effects caused by excessive addition, such as the impact of residual aluminum ions on subsequent processes.

[0077] The flocculant used in this step is PAM (polyacrylamide) at a concentration of 1‰-2‰. PAM is a polymer compound with good flocculation properties. It can adsorb suspended particles and colloidal substances in water and aggregate them into larger flocs through bridging, netting, etc., which facilitates subsequent filtration and separation.

[0078] The amount of PAM added is 3%-5% of the volume of the raffinate, which is intended to promote the rapid flocculation and sedimentation of suspended matter and sediment in the solution, and improve the filtration efficiency and defluorination effect.

[0079] After adding the defluorinating agent and flocculant, they need to be allowed to fully react in the raffinate. During this process, fluoride ions combine with aluminum ions to form aluminum fluoride precipitates, and PAM promotes the flocculation and sedimentation of suspended matter and precipitates. Usually, this process is accompanied by stirring or shaking to accelerate the reaction and mixing. After the reaction is completed, the formed precipitate (i.e., defluoridation residue) is separated from the defluoridation liquid by filtering. During the filtration process, the fluoride ion content in the defluoridation liquid is significantly reduced, while most of the lithium element is retained in the solution.

[0080] The defluorination process of the present application precipitates fluorine from the solution, and the defluorination rate reaches more than 99%, indicating that the process has extremely high defluorination efficiency. The entire defluorination process uses very little raw materials, and the defluorination residue produced can be further processed or recycled, which is in line with the concept of green chemistry and sustainable development.

[0081] Step S80, the defluorination liquid is crystallized by using a freeze crystallization method to remove potassium and sodium salts, and a lithium-containing solution is separated.

[0082] Freeze crystallization is a separation method that uses the property that the solubility of a solute in a solvent changes with temperature. For inorganic salts such as potassium and sodium salts, their solubility in water usually decreases as the temperature decreases. Therefore, when the defluorination liquid is cooled to a certain temperature, the potassium and sodium salts will reach a supersaturated state and precipitate crystals, thereby achieving separation from lithium ions.

[0083] Place the defluorination liquid in a cooling device, such as a freezer or ice-salt bath, and gradually lower its temperature. The cooling speed should be moderate to avoid uneven crystallization or reduced efficiency caused by too fast or too slow cooling.

[0084] As the temperature decreases, potassium and sodium salts in the defluorination liquid begin to precipitate crystals. At this time, stirring or circulating flow can be used to promote uniform precipitation of crystals and prevent agglomeration caused by local oversaturation.

[0085] When the crystallization process is completed, the precipitated potassium and sodium salt crystals are separated from the lithium-containing solution by filtration, centrifugation or sedimentation. The separated lithium-containing solution will contain a higher concentration of lithium ions, while impurities such as potassium and sodium salts are effectively removed.

[0086] As needed, the separated lithium-containing solution can be further processed, such as adjusting the pH value, removing residual impurities, etc., to improve its purity and stability.

[0087] In summary, the method for recovering lithium-containing industrial waste of the present application adds calcium carbonate and sulfate at the same time in a certain proportion, which can reduce the problem of high price of potassium sulfate in sulfate, and avoid the problems of excessive addition of limestone in the calcium carbonate method, low lithium recovery rate and difficulty in recovery, and can also avoid the problems of acid pollution and equipment corrosion involved in the sulfuric acid method, greatly improve the leaching rate, and is suitable for the characteristics and chemical composition structure of lithium-containing industrial waste.

[0088] The raw materials such as calcium carbonate and calcium sulfate used in the method for recycling lithium-containing industrial waste of the present application are all cheap and easily available raw materials. Among them, potassium sulfate can also be recovered and recycled from the brine leached from industrial waste, which is economical and environmentally friendly.

[0089] The lithium-containing industrial waste recovery method of the present application adopts the method of pressing the mixed material into cakes to avoid sintering and burning of the mixed material during the roasting process, and can also prevent the dust generated by the mixing and grinding from polluting the environment and being difficult to collect.

[0090] The dilute sulfuric acid leaching method adopted in the present application is helpful to improve the leaching rate and has a simple process. The leaching rate is above 92%, and can reach up to 95% at the highest. The elemental lithium content in the filter residue is less than 0.1%.

[0091] The present invention provides the following five embodiments

[0092] First embodiment:

[0093] Use a weighing scale to weigh 30g of industrial waste, 5g of calcium carbonate, 5g of calcium sulfate, and 5g of potassium sulfate, put them into a container and mix well to obtain 45g of a mixture, then transfer the mixture to a hydraulic press and adjust the pressure to 100Pa, press the mixture into a cake shape, then put the cake-shaped mixture into a muffle furnace and set the roasting conditions to 900℃ for 45min, take out the cake-shaped transformation material after cooling, put it into a grinder and grind it to 80 mesh to obtain 44g of crushed transformation material, mix the crushed transformation material and the prepared 45ml of 1% concentration dilute sulfuric acid and stir for 10min, after stirring, filter the mixed liquid to obtain 24ml of industrial waste leaching brine and 32g of industrial waste leaching residue, extract and separate the leaching brine with a p204 synergistic extraction system to obtain a raffinate, and precipitate and separate the raffinate with a defluorinating agent to remove impurities to obtain a defluoridated liquid and a defluoridated residue.

[0094] Second embodiment:

[0095] Weigh 25g of industrial waste, 5g of calcium carbonate, 5g of calcium sulfate, and 5g of potassium sulfate on a weighing scale, put them into a container and mix them well to obtain 40g of a mixture, then transfer the mixture to a hydraulic press and adjust the pressure to 100Pa to press the mixture into a cake shape, then put the cake-shaped mixture into a muffle furnace and set the roasting condition to 900℃ for 45min, take out the cake-shaped transformation material after cooling, put it into a grinder and grind it to 80 mesh to obtain 39g of crushed transformation material, mix the crushed transformation material with the prepared 40ml of 1% concentration of dilute sulfuric acid and stir for 10min, after stirring, filter the mixed liquid to obtain 19ml of industrial waste leaching brine and 28g of industrial waste leaching residue, extract and separate the leaching brine with a p204 synergistic extraction system to obtain a raffinate, and precipitate and separate the raffinate with a defluorinating agent to obtain a defluorinated liquid and a defluorinated residue.

[0096] Third embodiment:

[0097] Weigh 25g of industrial waste, 5g of calcium carbonate, 5g of calcium sulfate, and 5g of potassium sulfate on a weighing scale, put them into a container and mix them well to obtain 40g of a mixture, then transfer the mixture to a hydraulic press and adjust the pressure to 100Pa to press the mixture into a cake shape, then put the cake-shaped mixture into a muffle furnace and set the roasting condition to 950℃ for 30min, take out the cake-shaped transformation material after cooling, put it into a grinder and grind it to 80 mesh to obtain 40g of crushed transformation material, mix the crushed transformation material with the prepared 40ml of 1% concentration of dilute sulfuric acid and stir for 10min, after stirring, filter the mixed solution to obtain 20ml of industrial waste leaching brine and 26g of industrial waste leaching residue, extract and separate the leaching brine with a p204 synergistic extraction system to obtain a raffinate, and precipitate and separate the raffinate with a defluorinating agent to remove impurities to obtain a defluorinated liquid and a defluorinated residue.

[0098] Fourth embodiment:

[0099] Weigh 25g of industrial waste, 5g of calcium carbonate, 5g of calcium sulfate, and 5g of potassium sulfate on a weighing scale, put them into a container and mix them well to obtain 40g of a mixture, then transfer the mixture to a hydraulic press and adjust the pressure to 100Pa to press the mixture into a cake shape, then put the cake-shaped mixture into a muffle furnace and set the roasting condition to 900℃ for 45min, take out the cake-shaped transformation material after cooling, put it into a grinder and grind it to 80 mesh to obtain 39g of crushed transformation material, mix the crushed transformation material with 80ml of 1% dilute sulfuric acid prepared and stir for 10min, after stirring, filter the mixture to obtain 39ml of industrial waste leaching brine and 27g of industrial waste leaching residue, extract and separate the leaching brine with a p204 synergistic extraction system to obtain a raffinate, and precipitate and separate the raffinate with a defluorinating agent to obtain a defluorinated liquid and a defluorinated residue.

[0100] Fifth embodiment:

[0101] Weigh 25g of industrial waste, 5g of calcium carbonate, 5g of calcium sulfate, and 5g of potassium sulfate on a weighing scale, put them into a container and mix them well to obtain 40g of a mixture, then transfer the mixture to a hydraulic press and adjust the pressure to 100Pa to press the mixture into a cake shape, then put the cake-shaped mixture into a muffle furnace and set the roasting condition to 900℃ for 45min, take out the cake-shaped transformation material after cooling, put it into a grinder and grind it to 80 mesh to obtain 39g of crushed transformation material, mix the crushed transformation material with the prepared 40ml of 1% concentration of dilute sulfuric acid and stir for 30min, after stirring, filter the mixed liquid to obtain 16ml of industrial waste leaching brine and 28g of industrial waste leaching residue, extract and separate the leaching brine with a p204 synergistic extraction system to obtain a raffinate, and precipitate and separate the raffinate with a defluorinating agent to obtain a defluorinated liquid and a defluorinated residue.

[0102] See also Figure 2 It can be seen from the experimental test data that the conversion rate of crushed transformation materials is relatively high. The leaching rate of mixed leaching of crushed transformation materials and dilute sulfuric acid can reach more than 90%, or even 95%. The soluble lithium in the slag is very low and can be ignored. The removal rate of heavy metals and fluoride ions has reached more than 98%, proving that this method is feasible for green lithium extraction from lithium-containing industrial waste.

[0103] The applicant declares that the present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the method of the present invention, addition of auxiliary steps, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for recovering lithium-containing industrial waste, characterized in that: The method for recovering lithium-containing industrial waste comprises: The lithium-containing industrial waste, calcium carbonate, calcium sulfate and potassium sulfate are fully mixed to form a uniform mixture; Pressing the mixture into a cake-shaped mixture; roasting the cake-shaped mixed material to obtain a transition material; Grinding the transition material into transition material powder; The transformation material powder is mixed with 1% dilute sulfuric acid, stirred and leached, and filtered and separated to obtain leaching brine; Extract and separate the heavy metals in the leached brine to obtain a raffinate; Adding a defluorinating agent and a flocculant to the raffinate, filtering after sufficient reaction to obtain a defluorinating liquid and a defluorinating residue; The defluorination liquid crystallization adopts a freezing crystallization method to remove potassium and sodium salts, and separates to obtain a lithium-containing solution.

2. The method for recycling lithium-containing industrial waste according to claim 1, characterized in that: The lithium-containing industrial waste, the calcium carbonate, the calcium sulfate and the potassium sulfate are mixed in a mass percentage of 6:1:1:

1.

3. The method for recycling lithium-containing industrial waste according to claim 2, characterized in that: The step of extracting and separating the heavy metals in the leached brine to obtain a raffinate comprises: The leached brine is used as a raw material, and a p204 / 4pc co-extraction system is used as an extraction organic phase. The leached brine raw material is subjected to multi-stage countercurrent extraction under preset conditions; heavy metal ions in the leached brine enter the organic phase and are separated to obtain a lithium-containing raffinate.

4. The method for recycling lithium-containing industrial waste according to claim 3, characterized in that: The preset conditions include: The ratio of the leaching brine to the organic phase is 1, the pH of the leaching brine is adjusted to 3-6, and the brine is shaken at a speed of 200 r / min for 30 minutes.

5. The method for recycling lithium-containing industrial waste according to claim 3, characterized in that: The concentration of p204 / is 0.5 mol / L, and the concentration of 4pc is 1.5 mol / L.

6. The method for recycling lithium-containing industrial waste according to claim 1, characterized in that: The defluorinating agent is aluminum sulfate with a concentration of 10%-15%, and the added amount of the defluorinating agent is 1%-3% of the volume of the raffinate.

7. The method for recycling lithium-containing industrial waste according to claim 1, characterized in that: The flocculant is PAM with a concentration of 1‰-2‰, and the added amount of the flocculant is 3%-5% of the volume of the raffinate.

8. The method for recovering lithium-containing industrial waste according to any one of claims 1 to 7, characterized in that: The calcination temperature of the cake-shaped mixture is 900-1000° C., and the calcination time is 0.5-1h.

9. The method for recovering lithium-containing industrial waste according to any one of claims 1 to 7, characterized in that: The transformation material is ground to above 80 mesh.

10. The method for recovering lithium-containing industrial waste according to any one of claims 1 to 7, characterized in that: The molding pressure of the mixed material pressed cake is 50-100Pa.

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