Method for extracting lithium from amblygonite
By adding auxiliary materials to lithium phosphite to remove hydroxyl groups and free water, the equipment loss and yield reduction caused by water dissipation during the roasting process is solved, and efficient lithium extraction and cost savings are achieved.
Patent Information
- Application Number
- CN202510688801.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-26
- Publication Date
- 2025-08-08
AI Technical Summary
In the prior art, when extracting lithium from lithium phosphite, the equipment loss and lithium yield reduction caused by water extraction during the roasting process.
By mixing and roasting lithium phosphite with auxiliary materials such as sodium feldspar, quartz, kaolin, bauxite, potassium feldspar or granite, the hydroxyl groups and free water are removed, the melting point is increased, the kiln formation phenomenon during the roasting process is avoided, and the lithium extraction step is adopted.
It effectively reduces equipment losses during the roasting process, improves lithium yield, simplifies operating steps and equipment requirements, and reduces costs.
Smart Images
Figure CN120442958A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of lithium extraction, and in particular to a method for extracting lithium from lithium phosphate. Background Art
[0002] Lithium, the lightest metal, and its alloys and compounds have found widespread application in a wide range of fields, including new energy vehicles, nuclear power generation, surface modification of non-metallic minerals, and the production of daily necessities. Currently, the raw materials used in industry are generally aluminum-silicate lithium ores such as spodumene, petalite, and lepidolite. Unlike aluminum-silicate lithium ores (such as lepidolite and spodumene), lepidolite, as a fluorophosphate lithium ores, produces higher-quality lithium oxide.
[0003] Current methods for extracting lithium phosphate include mixing it with concentrated sulfuric acid and then roasting it to produce lithium carbonate. However, because lithium phosphate contains hydroxyl groups, free water, or water of crystallization, water release during mixing with concentrated sulfuric acid can lead to kiln calcination, which in turn causes equipment wear and reduces lithium yield. Summary of the Invention
[0004] The method for extracting lithium from lithium aluminum phosphate provided by the present invention can reduce the problem of material agglomeration in the kiln, thereby improving the yield of lithium.
[0005] The present invention achieves the above technical objectives through the following technical solutions:
[0006] A method for extracting lithium from lithium phosphate, comprising: transforming and roasting a raw material containing lithium phosphate and auxiliary materials, and then performing acidification to extract lithium;
[0007] Wherein, the auxiliary material is selected from one or more of albite, quartz, kaolin, bauxite, potassium feldspar and granite.
[0008] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the melting point of the raw material is higher than the transition roasting temperature.
[0009] According to the above-mentioned method for extracting lithium from lithium phosphate, the mass ratio of the lithium phosphate to the auxiliary material is 1:0.05-1:0.5.
[0010] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the temperature of the transition roasting is 500-900°C.
[0011] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the transition roasting time is 20-120 minutes.
[0012] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the average particle size of the raw material is 60-200 meshes.
[0013] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the acidification extraction includes the steps of mixing the transition roasting product with concentrated sulfuric acid to obtain an acidified material, roasting the acidified material and post-treating it to obtain a lithium-containing product.
[0014] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the acidified material is first calcined at 230-330°C and then calcined at 500-900°C for the second time.
[0015] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, in the acidifying material, the mass ratio of the transition roasting product to the concentrated sulfuric acid is 1:0.25-1:0.5.
[0016] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the time of the first roasting is 20-120 minutes.
[0017] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the time of the secondary roasting is 10-120 minutes.
[0018] The above-mentioned method for extracting lithium from lithium aluminum phosphate further includes the step of finely grinding the calcined product of the acidified material, and the average particle size of the product obtained after fine grinding is 60-200 meshes.
[0019] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the post-processing includes: slurry leaching, purification and impurity removal, lithium precipitation and purification of the calcined product of the acidified material.
[0020] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the slurry leaching includes: mixing the acidified material roasting product with water, stirring and filtering to obtain a lithium-containing leachate; wherein the mass ratio of the acidified material roasting product to water is 1:1-1:5.
[0021] According to the above-described method for extracting lithium from lithium aluminum phosphate, the purification and impurity removal includes: first adjusting the pH of the lithium-containing leachate to 8-9, then adjusting it to 10-12, filtering to obtain a first purified liquid, adding a soluble carbonate solution to the first purified liquid, filtering to obtain a second purified liquid, and removing impurities from the second purified liquid through a resin to obtain a third purified liquid.
[0022] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the lithium precipitation comprises: adding a soluble carbonate solution to the purified liquid after purification and impurity removal to obtain crude lithium carbonate.
[0023] According to the above-mentioned method for extracting lithium from lithium aluminum phosphate, the purification includes: washing and drying the crude product obtained after lithium precipitation for multiple times to obtain a finished product.
[0024] The present invention provides a method for extracting lithium carbonate from lithium phosphate. The method comprises mixing ore auxiliary materials such as albite, quartz, kaolin, and bauxite with the lithium phosphate and then roasting the mixture to remove hydroxyl groups, free water, or crystallization water. The removal effect of hydroxyl groups, free water, or crystallization water is better, which is beneficial to reducing the kiln agglomeration problem during the roasting process, and further beneficial to improving the lithium yield.
[0025] Secondly, these auxiliary materials are common minerals with a wide range of sources and low cost. The sodium, silicon, and aluminum elements they contain are inherent in the lithium phosphate mineral and will not affect the subsequent acidification and lithium extraction. Furthermore, because the raw materials contain auxiliary materials, the transformed material is loose and does not require fine grinding in a grinder. It can be directly used in subsequent acidification and roasting, which helps reduce the number of operating steps and equipment, shorten the method route, and save costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 The apparent results of the transition calcined products after transition calcination in Example 1 and Comparative Example 1 are shown;
[0027] Figure 2 The XRD pattern of the calcined product after transition calcination in Example 1;
[0028] Figure 3 This is the XRD pattern of the calcined product after transition calcination in Comparative Example 1. DETAILED DESCRIPTION
[0029] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are 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 shall fall within the scope of protection of the present invention.
[0030] Because lithium phosphate contains hydroxyl groups, it releases water during mixing with concentrated sulfuric acid, leading to kiln calcination during sintering, which in turn causes equipment loss and reduced lithium yield. Based on this, the present invention provides a method for extracting lithium from lithium phosphate, comprising: transforming and calcining a raw material containing lithium phosphate and auxiliary materials, followed by acidification to extract lithium; wherein the auxiliary materials are selected from one or more of albite, quartz, kaolin, bauxite, potassium feldspar, and granite.
[0031] The present invention mixes albite, quartz, kaolin, bauxite and the like with lithium phosphate and then roasts the mixture to remove hydroxyl groups, free water or crystal water. The physicochemical properties of the ores are different from those of the lithium phosphate. After mixing, the original crystal structure of the lithium phosphate can be destroyed, and the interaction force between molecules of different substances can be changed, which is beneficial to the removal of hydroxyl groups, free water and crystal water in the lithium phosphate, preventing the condensation of the materials during the roasting process, and improving the lithium yield. At the same time, after the ores are mixed with the lithium phosphate, the melting point of the raw materials is higher than that of the lithium phosphate. The higher melting point is beneficial to increasing the roasting temperature. The higher roasting temperature is beneficial to more completely removing the hydroxyl groups, free water or crystal water in the lithium phosphate, preventing the condensation of the materials due to water precipitation during the acid mixing process, and further improving the lithium yield.
[0032] Secondly, these auxiliary materials are common minerals with a wide range of sources and low cost. The sodium, silicon, and aluminum elements they contain are inherent in the lithium phosphate mineral and will not affect the subsequent acidification and lithium extraction. Furthermore, because the raw materials contain auxiliary materials, the transformed material is loose and does not require fine grinding in a grinder. It can be directly used in subsequent acidification and roasting, which helps reduce the number of operating steps and equipment, shorten the method route, and save costs.
[0033] It should be noted that pyroxenite often coexists with spodumene, quartz, mica, or beryl. Differences in impurity content can lead to differences in the melting point of pyroxenite. The transition roasting temperature of pyroxenite is generally between 500-900°C. Pyroxenite with a melting point above the transition roasting temperature is less likely to experience kiln agglomeration during transition roasting, while pyroxenite with a melting point below the transition roasting temperature is more likely to experience kiln agglomeration during transition roasting. This method is not only applicable to pyroxenite with a melting point above the transition roasting temperature, but is also more suitable for pyroxenite with a melting point below the transition roasting temperature.
[0034] After albite, quartz, kaolin, bauxite, potassium feldspar, granite and other ores are mixed with lithium phosphate, the melting point of the mixed raw materials is higher than the melting point of the initial lithium phosphate. When its melting point is raised to higher than the transition temperature, it is more conducive to reducing kiln agglomeration problems and increasing the lithium yield.
[0035] In some specific embodiments, the mass ratio of lithium phosphate to auxiliary materials is 1:0.05-1:0.5. For example, the mass ratio of lithium phosphate to auxiliary materials can be 1:0.05, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, or any range between any two of the aforementioned values. Mixing lithium phosphate in the aforementioned ratios generally ensures that the melting point of the raw materials is above the transition roasting temperature, thereby reducing kiln calcination problems and improving lithium yield.
[0036] In some specific embodiments, the transition calcination temperature is 500-900°C. For example, the transition calcination temperature can be 500°C, 600°C, 700°C, 800°C, 900°C, or a range between any two of the above values. The corresponding transition calcination time is generally 20-120 minutes. For example, it can be 20 minutes, 40 minutes, 60 minutes, 80 minutes, 100 minutes, 120 minutes, or a range between any two of the above values.
[0037] In some embodiments, the average particle size of the lithium phosphate ore and auxiliary materials is 60-200 mesh. Controlling the particle size of the raw materials before roasting facilitates complete roasting and subsequent acidification extraction. The method for achieving this particle size is not specifically limited, and common crushing and fine grinding pretreatment methods in the art can be used.
[0038] For example, the average particle size of the lithium phosphate ore and auxiliary materials can be 60 mesh, 80 mesh, 100 mesh, 120 mesh, 140 mesh, 160 mesh, 180 mesh, 200 mesh, and the range between any two of the above values.
[0039] In some embodiments, the post-processing includes the steps of mixing the transition roasting product with concentrated sulfuric acid to obtain an acidified material, roasting the acidified material, and post-processing the roasted product of the acidified material to obtain a lithium-containing product.
[0040] Furthermore, when the acidified material is first calcined at 230-330° C. and then calcined at 500-900° C. for a second time, the lithium extraction efficiency is higher and the waste disposal cost can be reduced.
[0041] For example, the primary calcination temperature may be 230° C., 250° C., 270° C., 290° C., 310° C., 330° C., or a range between any two of the above values.
[0042] The temperature of the secondary calcination may be 500° C., 600° C., 700° C., 800° C., 900° C., or a range between any two of the above values.
[0043] In some embodiments, the transition roasting product and concentrated sulfuric acid are mixed at a mass ratio of 1:0.25 to 1:0.5 to ensure sufficient reaction between the two. For example, the mass ratio of the transition roasting product to concentrated sulfuric acid can be 1:0.25, 1:0.3, 1:0.4, 1:0.5, or any range between any two of the above values.
[0044] In some specific embodiments, the low-temperature calcination time can be 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, or a range between any two of the above values.
[0045] The high temperature calcination time can be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, or a range between any two of the above values.
[0046] It is understandable that in order to ensure that the subsequent acidification extraction is more sufficient, the roasted product of the acidified material can also be finely ground. The average particle size of the finely ground product is generally controlled to be 60-200 meshes.
[0047] In some specific embodiments, the post-processing includes: slurry leaching, purification and impurity removal, lithium precipitation and purification of the roasted product of the acidified material.
[0048] In some specific embodiments, the slurry leaching comprises mixing the calcined product of the acidified material with water, stirring, and filtering to obtain a lithium-containing leachate; wherein the mass ratio of the calcined product of the acidified material to water is 1:1-1:5, and illustratively, can be 1:1, 1:2, 1:3, 1:4, 1:5, or any range between any two of the aforementioned values. The filtration method is not specifically limited, and can be a commonly used method in the art, such as suction filtration and filter press filtration.
[0049] After acid leaching, the lithium-containing leachate is purified and impurities removed. In some embodiments, the purification and impurity removal process includes adjusting the pH of the lithium-containing leachate to 8-9, then to 10-12, filtering to obtain a first purified solution, adding a soluble carbonate solution to the first purified solution, filtering to obtain a second purified solution, and passing the second purified solution through a resin for deep impurity removal to obtain a third purified solution.
[0050] Specifically, purification and impurity removal can be carried out by the following method: adding CaCO3 to the lithium-containing leachate to adjust the pH to 8-9, then adding a 30% by mass sodium hydroxide solution to adjust the pH to 11, removing impurities such as Al, P, Fe, and Mg, and filtering the solution to obtain a first purified liquid; adding a 20% by mass sodium carbonate solution to the first purified liquid to remove impurities such as calcium, and filtering to obtain a second purified liquid; the second purified liquid is then passed through multiple resins to deeply remove impurities such as Ca, P, and Mg to obtain a third purified liquid.
[0051] In some embodiments, the lithium precipitation comprises: adding a soluble carbonate solution to the purified solution after purification and impurity removal to obtain a crude lithium carbonate product. In some embodiments, the purification comprises: washing and drying the crude product obtained after lithium precipitation multiple times to obtain a finished product.
[0052] The present invention will be described in detail below with reference to specific embodiments.
[0053] Specific conditions not specified in the following examples and comparative examples were all carried out according to conventional conditions or conditions recommended by the manufacturer, and all reagents and instruments used were commercially available.
[0054] The lithium phosphate used in the following Examples 1-4 and Comparative Example 1 and the lithium phosphate used in Example 5 are lithium phosphate from different batches. The melting point of the lithium phosphate used in Examples 1-4 and Comparative Example 1 is below 800°C, and the melting point of the lithium phosphate used in Example 5 is above 800°C.
[0055] Example 1
[0056] This embodiment provides a method for extracting lithium from lithium phosphate, wherein the auxiliary material is albite, and specifically comprises the following steps:
[0057] Step 1: After the lithium phosphate aluminum oxide and sodium feldspar are crushed and finely ground, the mixture is passed through a 200-mesh sieve, and the mass ratio of the lithium phosphate aluminum oxide to the sodium feldspar is 1:0.3. The mixture is then calcined at 800° C. for 50 minutes to obtain a transition calcined product.
[0058] The apparent results of the transition roasting products can be found in Figure 1 , XRD test results see Figure 2 .
[0059] Step 2: After the transformation roasting product is cooled, it is evenly mixed with concentrated sulfuric acid at a mass ratio of 1:0.27, placed in a muffle furnace, and roasted at a temperature of 275°C for 60 minutes to obtain an acidified material.
[0060] Step 3: The acidified material was placed in a muffle furnace and calcined at 800°C for 80 minutes, then finely ground to 100 mesh, 1.5 times the weight of the crushed material was added with water, stirred at 25°C and 500 rpm for 60 minutes, and filtered to obtain the leachate and leach residue.
[0061] Step 4: Add CaCO3 to the leachate to adjust the pH to 8-9, then add 30% by mass sodium hydroxide solution to adjust the pH to 11, remove impurities such as Al, P, Fe, and Mg, and filter the solution to obtain the first purified solution.
[0062] Step 5: Add 20% by mass of sodium carbonate solution to the first purified liquid to remove impurities such as calcium, and filter to obtain a second purified liquid.
[0063] Step 6: The second purified liquid is passed through multiple resins to deeply remove impurities such as Ca, P, and Mg to obtain the third purified liquid.
[0064] Step 7: The third purified liquid is used to precipitate lithium with saturated sodium carbonate, and a battery-grade lithium carbonate product is obtained after multiple washings and drying.
[0065] Example 2
[0066] This embodiment provides a method for extracting lithium from lithium aluminum phosphate, wherein the auxiliary material is quartz, and specifically comprises the following steps:
[0067] Step 1: After the lithium apatite and quartz are crushed and finely ground, they are passed through a 120-mesh sieve, mixed in a mass ratio of lithium apatite to quartz of 1:0.5, and calcined at 750°C for 50 minutes.
[0068] Step 2: After the transformation roasting product is cooled, it is evenly mixed with concentrated sulfuric acid at a mass ratio of 1:0.3, placed in a rotary kiln, and roasted at a temperature of 275°C for 60 minutes to obtain an acidified material.
[0069] Step 3: The acidified material was placed in a rotary kiln and roasted at 800°C for 100 minutes. After that, it was finely ground to 100 mesh. Water 1.5 times the weight of the crushed material was added. The mixture was stirred at 25°C and 500 rpm for 60 minutes. The leachate and leach residue were filtered.
[0070] Step 4: Add CaCO3 to the leachate to adjust the pH to 8-9, then add 30% by mass sodium hydroxide solution to adjust the pH to 11, remove impurities such as Al, P, Fe, and Mg, and filter the solution to obtain the first purified solution.
[0071] Step 5: Add 20% by mass of sodium carbonate solution to the first purified liquid to remove impurities such as calcium, and filter to obtain a second purified liquid.
[0072] Step 6: The second purified liquid is passed through multiple resins to deeply remove impurities such as Ca, P, and Mg to obtain the third purified liquid.
[0073] Step 7: The third purified liquid is used to precipitate lithium with saturated sodium carbonate, and a battery-grade lithium carbonate product is obtained after multiple washings and drying.
[0074] Example 3
[0075] This embodiment provides a method for extracting lithium from lithium phosphate, wherein the auxiliary material is bauxite, and specifically comprises the following steps:
[0076] Step 1: After the lithium phosphate and bauxite are crushed and finely ground, they are passed through a 160-mesh sieve, mixed in a mass ratio of lithium phosphate to bauxite of 1:0.1, and calcined at 800°C for 60 minutes.
[0077] Step 2: After the transformation roasting product is cooled, it is evenly mixed with concentrated sulfuric acid at a mass ratio of 1:0.25, placed in a muffle furnace, and roasted at 300°C for 60 minutes to obtain an acidified material.
[0078] Step 3: The acidified material was placed in a muffle furnace and calcined at 800°C for 80 min, then finely ground to 100 mesh, 1.5 times the weight of the crushed material was added with water, stirred at 25°C and 500 rpm for 60 min, and filtered to obtain the leachate and leach residue.
[0079] Step 4: Add CaCO3 to the leachate to adjust the pH to 8-9, then add 30% by mass sodium hydroxide solution to adjust the pH to 11, remove impurities such as Al, P, Fe, and Mg, and filter the solution to obtain the first purified solution.
[0080] Step 5: Add 20% by mass of sodium carbonate solution to the first purified liquid to remove impurities such as calcium, and filter to obtain a second purified liquid.
[0081] Step 6: The second purified liquid is passed through multiple resins to deeply remove impurities such as Ca, P, and Mg to obtain the third purified liquid.
[0082] Step 7: The third purified liquid is used to precipitate lithium with saturated sodium carbonate, and a battery-grade lithium carbonate product is obtained after multiple washings and drying.
[0083] Example 4
[0084] This embodiment provides a method for extracting lithium from lithium phosphate, wherein the auxiliary material is kaolin, and the method specifically comprises the following steps:
[0085] Step 1: After the lithium phosphate aluminum oxide and kaolin are crushed and finely ground, they are passed through a 120-mesh sieve, mixed in a mass ratio of lithium phosphate aluminum oxide to kaolin of 1:0.2, and calcined at 800° C. for 60 minutes.
[0086] Step 2: After the transformation roasting product is cooled, it is evenly mixed with concentrated sulfuric acid at a mass ratio of 1:0.3, placed in a muffle furnace, and roasted at 300°C for 60 minutes to obtain an acidified material.
[0087] Step 3: The acidified material was placed in a muffle furnace and calcined at 800°C for 100 min. Then, it was finely ground to 100 mesh. Water 1.5 times the weight of the crushed material was added. The mixture was stirred at 25°C and 500 rpm for 60 min. The leachate and leach residue were obtained by filtration.
[0088] Step 4: Adjust the pH of the leachate to 8-9 with CaCO3, then add 30% by mass sodium hydroxide solution to adjust the pH to 11, remove impurities such as Al, P, Fe, and Mg, and filter the solution to obtain the first purified solution.
[0089] Step 5: Add 20% by mass of sodium carbonate solution to the first purified liquid to remove impurities such as calcium, and filter to obtain a second purified liquid.
[0090] Step 6: The second purified liquid is passed through multiple resins to deeply remove impurities such as Ca, P, and Mg to obtain the third purified liquid.
[0091] Step 7: The third purified liquid is used to precipitate lithium with saturated sodium carbonate, and a battery-grade lithium carbonate product is obtained after multiple washings and drying.
[0092] Example 5
[0093] This embodiment provides a method for extracting lithium from lithium phosphate, wherein the auxiliary material is albite, which is different from the lithium phosphate used in the above embodiments 1-4. The method specifically includes the following steps:
[0094] Step 1: After the lithium phosphate aluminum oxide and sodium feldspar are crushed and finely ground, they are passed through a 120-mesh sieve, mixed in a mass ratio of lithium phosphate aluminum oxide to sodium feldspar of 1:0.05, and calcined at 800°C for 60 minutes.
[0095] Step 2: After cooling, the material was finely ground into 200-mesh powder, mixed evenly with concentrated sulfuric acid at a mass ratio of 1:0.3, placed in a muffle furnace, and calcined at 300°C for 60 minutes to obtain an acidified material.
[0096] Step 3: The acidified material was placed in a muffle furnace and calcined at 800°C for 100 minutes, then finely ground to 100 mesh, 1.5 times the weight of the crushed material was added with water, stirred at 25°C and 500 rpm for 60 minutes, and filtered to obtain the leachate and leach residue.
[0097] Step 4: Adjust the pH of the leachate to 8-9 with CaCO3, then add 30% by mass sodium hydroxide solution to adjust the pH to 11, remove impurities such as Al, P, Fe, and Mg, and filter the solution to obtain the first purified solution.
[0098] Step 5: Add 20% by mass of sodium carbonate solution to the first purified liquid to remove impurities such as calcium, and filter to obtain a second purified liquid.
[0099] Step 6: The second purified liquid is passed through multiple resins to deeply remove impurities such as Ca, P, and Mg to obtain the third purified liquid.
[0100] Step 7: The third purified liquid is used to precipitate lithium with saturated sodium carbonate, and a battery-grade lithium carbonate product is obtained after multiple washings and drying.
[0101] Comparative Example 1
[0102] This comparative example provides a method for extracting lithium from lithium aluminum phosphate, which differs from Example 1 in that no auxiliary materials are added, and specifically comprises the following steps:
[0103] Step 1: crush and finely grind the lithium aluminum phosphate, pass it through a 120 mesh sieve, and then roast it at 800℃ for 60 minutes. The apparent results of the transformation roasting product can be found in Figure 1 , XRD test results see Figure 3 .
[0104] Step 2: After the transformation roasting product is cooled, the material is finely ground into a 200-mesh powder, mixed evenly with concentrated sulfuric acid at a mass ratio of 1:0.3, placed in a muffle furnace, and roasted at 300°C for 60 minutes to obtain an acidified material.
[0105] Step 3: The acidified material was placed in a muffle furnace and calcined at 800°C for 100 min. Then, it was finely ground to 100 mesh. Water 1.5 times the weight of the crushed material was added. The mixture was stirred at 25°C and 500 rpm for 60 min. The leachate and leach residue were obtained by filtration.
[0106] Step 4: Add CaCO3 to the leachate to adjust the pH to 8-9, then add 30% by mass sodium hydroxide solution to adjust the pH to 11, remove impurities such as Al, P, Fe, and Mg, and filter the solution to obtain the first purified solution.
[0107] Step 5: Add 20% by mass of sodium carbonate solution to the first purified liquid to remove impurities such as calcium, and filter to obtain a second purified liquid.
[0108] Step 6: The second purified liquid is passed through multiple resins to deeply remove impurities such as Ca, P, and Mg to obtain the third purified liquid.
[0109] Step 7: The third purified liquid is used to precipitate lithium with saturated sodium carbonate, and a battery-grade lithium carbonate product is obtained after multiple washings and drying.
[0110] Result Analysis
[0111] (1) XRD analysis
[0112] Figure 1 These are the apparent results of the calcined products after transition calcination in Example 1 and Comparative Example 1, where A is the apparent result in Example 1 and B is the apparent result in Comparative Example 1.
[0113] Figure 2 is the XRD pattern of the calcined product after transition calcination in Example 1, Figure 3 This is the XRD pattern of the calcined product after transition calcination in Comparative Example 1.
[0114] Depend on Figure 1 It can be seen that under the same transformation roasting temperature and time, low-melting-point lithium phosphate aluminum stone has a low melting point and is in a molten state during the transformation process, and will be agglomerated on the roasting equipment, such as Figure 1As shown in B, after adding auxiliary materials, the lithium aluminum phosphate after transformation roasting is still in a loose powder state, as shown in Figure 1 As shown in A.
[0115] Depend on Figure 2 It can be seen that under the same transition calcination temperature and time, the main molecular formula of the low melting point lithium aluminum phosphate after adding auxiliary materials in Example 1 is LiAl (PO4) F ( Figure 2 As shown), it shows that the hydroxyl groups are completely removed, while in the control group without auxiliary materials, lithium phosphate aluminum oxide is hardened, and its main molecular formula is LiAl (PO4) (OH) 0.119 F 0.881 ( Figure 3 ), indicating that a large number of hydroxyl groups remain.
[0116] (2) The leachate in each of the above examples and comparative examples was diluted to an appropriate multiple and then tested for Li content using ICP. The original ore and leaching residue were digested and then tested for Li content using ICP. The comprehensive recovery rate of lithium was calculated at the same time. The results are shown in Table 1 below.
[0117] Among them, the comprehensive recovery rate of lithium is calculated as follows:
[0118] Li recovery rate = 1-(lithium content in raw materials - lithium content in leaching residue) / lithium content in raw materials.
[0119] Table 1
[0120]
[0121] From the above results, it can be seen that the lithium content in the leaching residue of Examples 1-5 is lower, the lithium content in the leachate is higher, and the comprehensive recovery rate of lithium is also higher, indicating that the addition of auxiliary materials such as albite, quartz, kaolin, bauxite, potassium feldspar, granite, etc. is beneficial to improving the yield of lithium.
[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for extracting lithium from lithium phosphate, characterized in that: include: The raw materials including lithium aluminum phosphate and auxiliary materials are transformed and roasted, and then acidified to extract lithium; Wherein, the auxiliary material is selected from one or more of albite, quartz, kaolin, bauxite, potassium feldspar and granite.
2. The method for extracting lithium from lithium phosphate according to claim 1, wherein The melting point of the raw material is higher than the transition roasting temperature; and / or The mass ratio of the lithium aluminum phosphate to the auxiliary material is 1:0.05-1:0.
5.
3. The method for extracting lithium from lithium phosphate according to claim 1 or 2, characterized in that: The temperature of the transition roasting is 500-900°C; and / or The transition roasting time is 20-120min.
4. The method for extracting lithium from lithium phosphate according to any one of claims 1 to 3, characterized in that: The average particle size of the raw materials is 60-200 meshes.
5. The method for extracting lithium from lithium phosphate according to any one of claims 1 to 4, characterized in that: The acidification extraction comprises the steps of mixing the transition roasting product with concentrated sulfuric acid to obtain an acidified material, roasting the acidified material and performing post-processing to obtain a lithium-containing product.
6. The method for extracting lithium from lithium phosphate according to claim 5, characterized in that: The acidified material is first calcined at 230-330°C and then calcined at 500-900°C for a second time; and / or In the acidifying material, the mass ratio of the transition roasting product to the concentrated sulfuric acid is 1:0.25-1:0.
5.
7. The method for extracting lithium from lithium phosphate according to claim 6, characterized in that: The time of the first roasting is 20-120 min; and / or The secondary roasting time is 10-120 minutes.
8. The method for extracting lithium from lithium phosphate according to any one of claims 5 to 7, characterized in that: The method further comprises the step of finely grinding the calcined product of the acidified material, wherein the average particle size of the product obtained after fine grinding is 60-200 meshes.
9. The method for extracting lithium from lithium phosphate according to any one of claims 5 to 8, characterized in that: The post-processing includes: slurry adjustment and leaching, purification and impurity removal, lithium precipitation and purification of the acidified material roasting product.
10. The method for extracting lithium from lithium phosphate according to claim 9, characterized in that: The slurry leaching comprises: mixing the acidified material roasted product with water, stirring and filtering to obtain a lithium-containing leachate; wherein the mass ratio of the acidified material roasted product to water is 1:1-1:5; and / or The purification and impurity removal comprises: adjusting the pH of the lithium-containing leachate to 8-9, and then adjusting it to 10-12, filtering to obtain a first purified liquid, adding a soluble carbonate solution to the first purified liquid, filtering to obtain a second purified liquid, and removing impurities from the second purified liquid through a resin to obtain a third purified liquid; and / or The lithium precipitation comprises: adding a soluble carbonate solution to the purified liquid after purification and impurity removal to obtain a crude lithium carbonate product; and / or The purification comprises: washing and drying the crude product obtained after lithium precipitation for multiple times to obtain a finished product.