Method for removing impurity iron in rare earth material
By taking advantage of the differences in the physical properties of the complexes between rare earths and iron, and using the hydrochloric acid solution method and complex precipitation sublimation cooling technology, the impurity iron in the rare earth materials was successfully removed and high purification of rare earths was achieved.
Patent Information
- Application Number
- CN202411464510.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-21
- Publication Date
- 2025-01-24
AI Technical Summary
The prior art is difficult to efficiently remove impurity iron from rare earth materials, making it difficult to achieve rare earth purification.
By utilizing the differences in the physical properties of rare earth complexes and iron complexes, the hydrochloric acid optimal solution method is used to obtain the leachate containing rare earth and iron, and then mix it with the complex solution to react in an environment with a pH of 5-8 to form a complex precipitate. . Then it is sublimated in a vacuum environment at a sublimation temperature of 130-160°C, and gradually cooled and sublimated in the cooling temperature section of 150-55°C, and the sublimation products within 125-105°C are collected to remove impurity iron.
The efficient removal of impurity iron in rare earth materials has been achieved, and high -purity rare earth materials have been obtained.
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Figure CN119351742A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of rare earth purification, and in particular to a method for removing impure iron in rare earth materials. Background Art
[0002] Although the rare earth industry has been developed for decades, there are still major defects in the extraction and separation of rare earth elements. Non-rare earth elements have a great negative impact on the application of rare earths. For example, impurities such as calcium, iron, and silicon can act as fluorescence quenching centers, especially 10 -7 mmolFe 3+ This will make Eu 3+ Luminescence quenching. In the prior art, the cascade extraction method is commonly used to separate and purify rare earths, which can obtain rare earths with a content of 5-6N. It is difficult to prepare high-purity rare earth precursors by cascade extraction, so it is necessary to find new ways and methods to efficiently remove the important impurity iron in the production process of high-purity rare earths. Summary of the invention
[0003] The object of the present invention is to provide a method for removing impure iron in rare earth materials, by utilizing the difference in physical properties between rare earth complexes and iron complexes to remove impure iron, thereby obtaining high-purity rare earth materials.
[0004] The present invention provides a method for removing impure iron in a rare earth material, comprising: obtaining a leaching solution containing rare earth and iron based on a hydrochloric acid optimal solution method, stirring and mixing the leaching solution with a complex solution, reacting the mixture in an environment with a pH value of 5-8, adding water to adjust the solubility to precipitate a precipitate, and then separating the precipitate to obtain a complex precipitate; sublimating the complex precipitate at a sublimation temperature of 130-160° C. in a vacuum environment, gradually cooling and condensing the precipitate in a cooling temperature range of 150-55° C., and collecting the condensed product within a temperature range of 125-105° C. to obtain the rare earth material with the impurity iron removed; wherein the sublimation temperature is greater than or equal to the maximum temperature of the cooling temperature range.
[0005] The removal method provided by the present invention comprises the following steps: preparing rare earth complexes and iron complexes by complexing rare earth elements and iron elements, and removing impure iron elements therein by utilizing the difference in the desublimation temperature between the rare earth complexes and the iron complexes, thereby purifying the rare earths to obtain high-purity rare earth materials.
[0006] Optionally, at least one of 2,2,6,6-tetramethyl-3,5-heptanedione, 1,1,1,5,5,5-hexafluoroacetylacetone and 1,1,1-trifluoroacetylacetone is dissolved in the complex solution. The rare earth element and the iron element can be complexed by the complex, thereby obtaining a rare earth complex and an iron complex with a significant difference in sublimation temperature and desublimation temperature.
[0007] Optionally, the molar ratio of the complex solute in the complex solution to the metal element in the leaching solution is (1-10):1, and the metal element includes rare earth elements and iron elements.
[0008] Optionally, the solvent in the complexing solution includes an alcohol solvent.
[0009] Optionally, the rare earth in the leaching solution includes lanthanide rare earths, and the lanthanide rare earths include one of yttrium and europium.
[0010] Optionally, after the leachate and the complex solution are stirred and mixed, a pH adjuster is added to adjust the pH to 5-8, and the pH adjuster includes one of triethylamine, sodium hydroxide and sodium methoxide.
[0011] Optionally, the leaching solution and the complexing solution are stirred and mixed, and then reacted in an environment with a pH of 5-8 for 2-4 hours.
[0012] Optionally, the leaching solution and the complexing solution are stirred and mixed, and then reacted in an environment of 25-35° C. and pH 5-8.
[0013] Optionally, after the reaction in an environment with a pH of 5-8, water is added in a volume ratio of 1:(1.5-2.5) to the reaction solution and stirred to adjust the solubility.
[0014] Optionally, water is added to adjust the solubility to precipitate the solution, and the solution is allowed to stand at 20-35° C. for 2-3 hours before separation.
[0015] Optionally, after separation, the complex precipitate is dried under vacuum at 50-80°C.
[0016] Optionally, when obtaining a leachate containing rare earth and iron based on the hydrochloric acid preferential solution method, the rare earth material is stirred and reacted in hydrochloric acid, water is added, and the solvent is evaporated to obtain rare earth chloride, and the rare earth chloride is dissolved in an alcohol solvent to obtain a leachate; the rare earth material includes rare earth and iron.
[0017] Optionally, the complex precipitate is sublimated in a vacuum environment at a sublimation temperature of 130-160° C. for 2-8 h.
[0018] Optionally, when gradual cooling and desublimation are performed in a cooling temperature section of 150-55° C., the cooling temperature section includes a plurality of cooling temperature zones with decreasing temperature gradients, and the temperature gradients of adjacent cooling temperature zones are independent of each other.
[0019] Optionally, when gradually cooling and desublimating in a cooling temperature section of 150-55° C., the temperature of the cooling temperature section decreases linearly.
[0020] Optionally, when the gradual cooling and desublimation is performed in a cooling temperature section of 150-55° C., the length of the cooling temperature section is 100-150 cm.
[0021] Optionally, the desublimation product is collected at 125-105° C. to obtain the rare earth material with iron impurities removed, and the rare earth material with iron impurities removed is subjected to cyclic sublimation and desublimation collection, and the number of cycles is 2-5 times.
[0022] Optionally, after collecting the desublimation product within 125-105° C. to obtain the rare earth material from which the impurity iron is removed, the rare earth material from which the impurity iron is removed is calcined in an oxygen-containing atmosphere to obtain the oxidized rare earth material from which the impurity iron is removed.
[0023] In a second aspect, the present invention provides a method for removing impure iron in rare earth materials, comprising: obtaining a leaching solution containing rare earth and iron based on a hydrochloric acid optimal solution method, stirring and mixing the leaching solution with a complex solution, reacting the mixture in an environment with a pH of 5-8, adding water to adjust the solubility to precipitate the precipitate, and then separating the precipitate to obtain a complex precipitate; sublimating the complex precipitate in a vacuum environment at a sublimation temperature of 100-130°C, and collecting the residue to obtain a rare earth material with the impurity iron removed.
[0024] The removal method provided by the present invention utilizes the difference in sublimation temperature between the rare earth complex and the iron complex to remove the impurity iron element therein, thereby purifying the rare earth to obtain a high-purity rare earth material.
[0025] Optionally, the complex precipitate is sublimated in a vacuum environment at a sublimation temperature of 100-130° C. for 2-8 h.
[0026] Optionally, after collecting the residue to obtain the rare earth material from which the impurity iron is removed, the rare earth material from which the impurity iron is removed is subjected to cyclic sublimation and the residue is collected, and the number of cycles is 2-5 times.
[0027] Optionally, after collecting the residue to obtain the rare earth material from which the impurity iron is removed, the rare earth material from which the impurity iron is removed is calcined in an oxygen-containing atmosphere to obtain the oxidized rare earth material from which the impurity iron is removed. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 is the removal rate of iron in the rare earth material in Examples 1 to 4 of the present invention;
[0029] Figure 2 is the removal rate of iron in the rare earth material in Examples 1 and 5 to 7 of the present invention;
[0030] Figure 3 is the removal rate of iron in the rare earth material in Examples 8 to 11 of the present invention;
[0031] Figure 4 is the removal rate of iron in the rare earth material in Examples 8, 12 to 14 of the present invention;
[0032] Figure 5 is the removal rate of iron in the rare earth material in Examples 15 to 18 of the present invention;
[0033] Figure 6 is the removal rate of iron in the rare earth material in Examples 15 and 19 to 22 of the present invention;
[0034] Figure 7 is a graph showing changes in the content of iron in the rare earth material in Examples 23 and 24 of the present invention;
[0035] Figure 8 The present invention provides a flowchart of a method for removing impure iron from rare earth materials. DETAILED DESCRIPTION
[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with general skills in the field to which the present invention belongs.
[0037] See also Figure 8 The present invention provides a method for removing impurity iron in rare earth materials, comprising:
[0038] S1. Obtaining a leachate containing rare earth and iron based on a hydrochloric acid optimal solution method, stirring and mixing the leachate and the complex solution, reacting them in an environment with a pH of 5-8, adding water to adjust the solubility to precipitate, and then separating to obtain a complex precipitate;
[0039] S2. After the complex precipitate is sublimated at a sublimation temperature of 130-160° C. in a vacuum environment, it is gradually cooled and condensed in a cooling temperature range of 150-55° C., and the condensed product at 125-105° C. is collected to obtain a rare earth material with iron impurities removed.
[0040] In addition, the sublimation temperature is greater than or equal to the maximum temperature of the cooling temperature section. Specifically, the rare earth includes lanthanide rare earth, and the lanthanide rare earth includes one of europium and yttrium.
[0041] In fact, after the leachate is stirred and mixed with the complex solution, it is conducive to the rare earth chloride, ferric chloride and complex solute to be fully mixed, so that the rare earth element and the iron element are complexed in an environment of pH 5-8, thereby obtaining a rare earth complex and an iron complex, and adding water can adjust the solubility of the rare earth complex and the iron complex in the solution, and then precipitate to obtain a complex precipitate. Specifically, the solvent in the leachate includes an alcohol solvent, such as methanol, ethanol, etc., and the alcohol solvent can be used to dissolve the ferric chloride and the rare earth chloride to obtain a uniformly mixed leachate.
[0042] In some embodiments, when the leachate and the complexing solution are stirred and mixed, at least one of 2,2,6,6-tetramethyl-3,5-heptanedione (CAS: 1118-71-4), 1,1,1,5,5,5-hexafluoroacetylacetone (CAS: 1522-22-1), and 1,1,1-trifluoroacetylacetone (CAS: 367-57-7) is dissolved in the complexing solution used. In fact, by selecting the above-mentioned complexing solutes and complexing the rare earth elements and iron elements, the sublimation temperature and coagulation temperature of the obtained rare earth complex and iron complex have significant differences, which is conducive to sublimation separation.
[0043] In some embodiments, when the leachate and the complex solution are stirred and mixed, the molar ratio of the complex solute in the complex solution to the metal elements (including rare earth elements and iron elements) in the leachate is (1-10):1, which is conducive to fully complexing and precipitating the rare earth elements and iron elements in the leachate, avoiding the loss of rare earth elements during the purification process, and thus improving the purification yield. Specifically, the solvent used in the complex solution includes an alcohol solvent, and in fact, the alcohol solvent used in the complex solution can be the same as the solvent of the leachate.
[0044] In some embodiments, after the leachate and the complex solution are stirred and mixed, a pH regulator is added to adjust the pH to 5-8. In fact, the rare earth chloride in the leachate is acidic after being dissolved, and the use of a pH regulator to adjust the pH is conducive to the formation of rare earth complexes and iron complexes. Specifically, the pH regulator includes one of triethylamine, sodium hydroxide, and sodium methoxide. Preferably, after the leachate and the complex solution are stirred and mixed, a pH regulator can be added to adjust the pH to an acidic environment of 5-6.
[0045] In some embodiments, after the leachate and the complex solution are stirred and mixed, a pH adjuster is added to adjust the pH to 5-8 and then stirred for 2-4 hours, so as to facilitate the rare earth element, the iron element and the complex solvent to fully react, thereby generating a rare earth complex and an iron complex, and the rare earth complex and the iron complex can be dissolved in the mixture of the leachate and the complex solution. Specifically, after adjusting the pH to 5-8, the stirring reaction is carried out in an environment of 25-35°C.
[0046] In some embodiments, after stirring the reaction in an environment with a pH of 5-8, water is added in a volume ratio of 1: (1.5-2.5) to the reaction solution (the mixed solution after the leachate and the complex solution are mixed and reacted) to adjust the solubility. In fact, the addition of water can dilute the alcohol solvent in the reaction solution and reduce the solubility of the rare earth complex and the iron complex, thereby promoting the precipitation of the rare earth complex and the iron complex.
[0047] In some embodiments, the reaction is stirred and water is added to adjust the solubility to precipitate, and then the mixture is allowed to stand for 2-4 hours at 20-35° C. before separation. In fact, the precipitation amount and precipitation rate of the rare earth complex and the iron complex can be increased by standing. In the separation process, separation means commonly used in the art, such as vacuum filtration, filtration separation, etc., can be used, so that solid-liquid separation is necessary.
[0048] Specifically, after stirring the reaction and adding water to adjust the solubility to precipitate, the precipitate is allowed to stand and separate, and then the precipitate is circulated and washed with deionized water. In fact, after the precipitate is separated, it is dried in a vacuum environment at 50-80°C to obtain a complex precipitate.
[0049] In some embodiments, when obtaining a leachate containing rare earth and iron based on the hydrochloric acid preferential solution method, rare earth material is stirred in hydrochloric acid for reaction, water is added, and the solvent is evaporated to obtain rare earth chloride, and the rare earth chloride is dissolved in an alcohol solvent to obtain a leachate; wherein the rare earth material includes rare earth and iron.
[0050] In some embodiments, the complex precipitate is sublimated at a sublimation temperature of 130-160° C. for 2-8 hours in a vacuum environment, which is beneficial for fully sublimating the rare earth complex and the iron complex in the complex precipitate and for fully separating the rare earth elements and the iron elements in the complex precipitate.
[0051] In some embodiments, when gradually cooling and desublimating in a cooling temperature section of 150-55°C, the cooling temperature section includes a plurality of cooling temperature zones with decreasing temperature gradients, and the temperature gradients of adjacent cooling temperature zones are independent of each other. In fact, by cooling the sublimated rare earth complex and iron complex in the cooling temperature section, the different desublimation points of the rare earth complex and the iron complex can be utilized to collect the rare earth complex and the iron complex in different cooling temperature zones. Specifically, the temperature gradients of adjacent cooling temperature zones are independently 10-20°C. In fact, the length of the cooling temperature section is 100-150cm, and the lengths of the plurality of cooling temperature zones are independently 5-15cm. In fact, the temperatures of the plurality of cooling temperature sections decrease linearly.
[0052] In some embodiments, the desublimation product collected at 125-105° C. is used to obtain the rare earth material with iron impurities removed, and the rare earth material with iron impurities removed is subjected to cyclic sublimation and desublimation collection, and the number of cycles is 2-5. In fact, multiple cycles of sublimation purification are beneficial to improving the removal rate of iron impurities and improving the purification effect of rare earth elements.
[0053] In some embodiments, after collecting the desublimation product within 125-105° C. to obtain the rare earth material with iron impurities removed, the rare earth material with iron impurities removed is calcined in an oxygen-containing atmosphere to obtain the oxidized rare earth material with iron impurities removed.
[0054] Similarly, the present invention also provides another method for removing impure iron from rare earth materials, which is different from any of the above optional embodiments in that the complex precipitate is sublimated at a sublimation temperature of 100-130° C. in a vacuum environment, and the residue is collected to obtain the rare earth material with the impurity iron removed. In fact, the residual rare earth material is obtained by sublimating and removing the iron complex at 100-130° C.
[0055] Specifically, the complex precipitate is sublimated in a vacuum environment at a sublimation temperature of 100-130° C. for 2-8 hours, which is conducive to the full removal of the iron complex in the complex precipitate, thereby improving the removal efficiency of impurity iron and the purity of the obtained rare earth material.
[0056] Specifically, after collecting the residue to obtain the rare earth material with iron impurities removed, the rare earth material with iron impurities removed is subjected to cyclic sublimation and the residue is collected, and the number of cycles is 2-5 times. By performing the cycle, the removal efficiency of iron impurities and the purity of the obtained rare earth material can be further improved. Similarly, the rare earth material with iron impurities removed can be calcined in an oxygen-containing atmosphere to obtain an oxidized rare earth material with iron impurities removed.
[0057] Preparation Example 1
[0058] In this preparation example 1, a rare earth solution to be separated is prepared, including: taking 0.5 mL, 1 mol / L ferric chloride methanol solution and 49.5 mL, 1 mol / L europium chloride methanol solution and uniformly mixing them to prepare a rare earth solution to be separated with a ferric chloride concentration of 0.01 mol / L and a europium chloride concentration of 0.99 mol / L.
[0059] Preparation Example 2
[0060] In this preparation example 2, a rare earth solution to be separated is prepared, including: taking 0.5 mL, 1 mol / L ferric chloride methanol solution and 49.5 mL, 1 mol / L yttrium chloride methanol solution and mixing them evenly to prepare a rare earth solution to be separated with a ferric chloride concentration of 0.01 mol / L and a yttrium chloride concentration of 0.99 mol / L.
[0061] Preparation Example 3
[0062] This preparation example 3 provides a method for preparing a rare earth leaching solution, comprising: stirring and mixing 3.52 g of europium oxide rare earth material (purity 3N, impurities including iron element) with 2.19 g of hydrochloric acid, adding 20 mL of deionized water and evaporating the solvent to obtain a chlorinated mixture, and dissolving the chlorinated mixture in methanol to obtain a rare earth leaching solution.
[0063] Preparation Example 4
[0064] This preparation example 4 provides a method for preparing a rare earth leaching solution, comprising: stirring and mixing 3.52 g of europium oxide rare earth material (purity 4N, impurities including iron element) with 2.19 g of hydrochloric acid, adding 20 mL of deionized water and evaporating the solvent to obtain a chlorinated mixture, and dissolving the chlorinated mixture in methanol to obtain a rare earth leaching solution.
[0065] Example 1
[0066] This embodiment 1 provides a method for removing impurity iron in rare earth materials, comprising the following steps:
[0067] S1. After 25 mL of the rare earth solution to be separated prepared in Preparation Example 1 and 75 mL of a 1 mol / L 2,2,6,6-tetramethyl-3,5-heptanedione (CAS: 1118-71-4) solution were stirred and mixed, triethylamine was added to adjust the pH to 5.5 and stirred for reaction, 184 mL of deionized water was added and stirred, and then allowed to stand at room temperature of 25° C. for 3 h, and the solid obtained by filtration was vacuum dried after reduced pressure filtration to obtain a complex precipitate;
[0068] S2. Place the complex precipitate in a sublimator in a vacuum state, set the sublimation temperature of the complex precipitate to 160°C, and set the central temperatures of the cooling zones of the sublimation products to 145°C, 130°C, 115°C, 100°C, 85°C, 70°C and 55°C, respectively. Sublime and keep warm for 2 hours and then cool to room temperature. Collect the sublimation products in the cooling range of 125-105°C to obtain the rare earth material with iron impurities removed.
[0069] Example 2
[0070] This embodiment 2 provides a method for removing impurity iron in rare earth materials. The difference from embodiment 1 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 140°C, and the central temperatures of the cooling zone of the sublimation product are set to 127°C, 114°C, 101°C, 88°C, 75°C, 62°C and 49°C, respectively.
[0071] Example 3
[0072] This embodiment 3 provides a method for removing impurity iron in rare earth materials. The difference from embodiment 1 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 150°C, and the central temperatures of the cooling zone of the sublimation product are set to 135°C, 120°C, 105°C, 90°C, 75°C, 60°C and 45°C, respectively.
[0073] Example 4
[0074] This embodiment 4 provides a method for removing impurity iron in rare earth materials. The difference from embodiment 1 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 170°C, and the center temperatures of the cooling zone of the sublimation product are set to 150°C, 130°C, 110°C, 90°C, 70°C, 50°C and 30°C, respectively.
[0075] Example 5
[0076] This embodiment 5 provides a method for removing impurity iron in rare earth materials, which is different from the embodiment 1 in that sublimation and heat preservation are performed for 4 hours in step S2.
[0077] Example 6
[0078] This embodiment 6 provides a method for removing impure iron in rare earth materials, which is different from embodiment 1 in that sublimation and heat preservation are performed for 6 hours in step S2.
[0079] Example 7
[0080] This embodiment 6 provides a method for removing impure iron in rare earth materials, which is different from embodiment 1 in that sublimation and heat preservation are performed for 8 hours in step S2.
[0081] Example 8
[0082] This Example 8 provides a method for removing impurity iron in rare earth materials. The difference from Example 1 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 110°C, and the center temperatures of the cooling zone of the sublimation product are set to 100°C, 90°C, 80°C, 70°C, 60°C, 50°C and 40°C, respectively.
[0083] Example 9
[0084] This Example 9 provides a method for removing impurity iron in rare earth materials. The difference from Example 1 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 130°C, and the center temperatures of the cooling zone of the sublimation product are set to 110°C, 106°C, 94°C, 82°C, 70°C, 58°C and 46°C, respectively.
[0085] Example 10
[0086] This embodiment 10 provides a method for removing impurity iron in rare earth materials. The difference from embodiment 1 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 120°C, and the center temperatures of the cooling zone of the sublimation product are set to 110°C, 100°C, 90°C, 80°C, 70°C, 60°C and 50°C, respectively.
[0087] Embodiment 11
[0088] This Example 11 provides a method for removing impurity iron in rare earth materials. The difference from Example 1 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 100°C, and the center temperatures of the cooling zone of the sublimation product are set to 92°C, 84°C, 76°C, 68°C, 60°C, 52°C and 44°C, respectively.
[0089] Example 12
[0090] This embodiment 12 provides a method for removing impurity iron in rare earth materials, which is different from embodiment 8 in that sublimation and heat preservation are performed for 4 hours in step S2.
[0091] Embodiment 13
[0092] This embodiment 13 provides a method for removing impure iron in rare earth materials, which is different from embodiment 8 in that sublimation and heat preservation are performed for 6 hours in step S2.
[0093] Embodiment 14
[0094] This embodiment 14 provides a method for removing impure iron in rare earth materials, which is different from embodiment 8 in that sublimation and heat preservation are performed for 8 hours in step S2.
[0095] Embodiment 15
[0096] This embodiment 15 provides a method for removing impurity iron in rare earth materials, comprising the following steps:
[0097] S1. After 25 mL of the rare earth solution to be separated prepared in Preparation Example 2 and 75 mL of a 1 mol / L 2,2,6,6-tetramethyl-3,5-heptanedione (CAS: 1118-71-4) solution were stirred and mixed, triethylamine was added to adjust the pH to 5.5 and stirred for reaction, 168 mL of deionized water was added and stirred, and then allowed to stand at room temperature of 25° C. for 3 h, and the solid matter obtained by filtration was vacuum dried after reduced pressure filtration to obtain a complex precipitate;
[0098] S2. Place the complex precipitate in a sublimator in a vacuum state, set the sublimation temperature of the complex precipitate to 140°C, and set the central temperatures of the cooling zones of the sublimation products to 127°C, 114°C, 101°C, 88°C, 75°C, 62°C and 49°C, respectively. Sublime and keep warm for 4 hours and then cool to room temperature. Collect the sublimation products in the cooling range of 100-92°C to obtain the rare earth material with iron impurities removed.
[0099] Example 16
[0100] This Example 16 provides a method for removing impure iron in rare earth materials, which is different from Example 15 in that sublimation and insulation are performed for 2 hours in step S2.
[0101] Embodiment 17
[0102] This Example 17 provides a method for removing impure iron in rare earth materials, which is different from Example 15 in that sublimation and insulation are performed for 6 hours in step S2.
[0103] Embodiment 18
[0104] This Example 18 provides a method for removing impure iron in rare earth materials, which is different from Example 15 in that sublimation and insulation are performed for 8 hours in step S2.
[0105] Embodiment 19
[0106] This Example 19 provides a method for removing impure iron in rare earth materials. The difference from Example 15 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 130°C, and the center temperatures of the cooling zone of the sublimation product are set to 110°C, 106°C, 94°C, 82°C, 70°C, 58°C and 46°C, respectively.
[0107] Embodiment 20
[0108] This Example 20 provides a method for removing impurity iron in rare earth materials. The difference from Example 15 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 150°C, and the center temperatures of the cooling zone of the sublimation product are set to 135°C, 120°C, 105°C, 90°C, 75°C, 60°C and 45°C, respectively.
[0109] Embodiment 21
[0110] This Example 21 provides a method for removing impure iron in rare earth materials. The difference from Example 15 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 160°C, and the center temperatures of the cooling zone of the sublimation product are set to 145°C, 130°C, 115°C, 100°C, 85°C, 70°C and 55°C, respectively.
[0111] Embodiment 22
[0112] This Example 22 provides a method for removing impurity iron in rare earth materials. The difference from Example 15 is that in step S2, the sublimation temperature of the sublimator for the complex precipitate is set to 170°C, and the center temperatures of the cooling zone of the sublimation product are set to 150°C, 130°C, 110°C, 90°C, 70°C, 50°C and 30°C, respectively.
[0113] Embodiment 23
[0114] This embodiment 23 provides a method for removing impurity iron in rare earth materials, comprising the following steps:
[0115] S1. After 25 mL of the rare earth leachate obtained in Preparation Example 3 was stirred and mixed with 75 mL of 1 mol / L 2,2,6,6-tetramethyl-3,5-heptanedione (CAS: 1118-71-4) solution, triethylamine was added to adjust the pH to 5.5 and stirred for reaction, and then 184 mL of deionized water was added and stirred, and then allowed to stand at room temperature of 25° C. for 3 h, and the solid obtained by filtration was vacuum dried after reduced pressure filtration to obtain a complex precipitate;
[0116] S2. Place the complex precipitate in a sublimator under vacuum, set the sublimation temperature of the biochemical analyzer for the complex precipitate to 160°C, and set the central temperatures of the cooling zones of the sublimation products to 145°C, 130°C, 115°C, 100°C, 85°C, 70°C and 55°C, respectively. After sublimation and heat preservation for 2 hours, collect the sublimation products in the cooling range of 125-105°C and place them in the sublimator again for sublimation and sublimation collection. Repeat three times to obtain the rare earth material with iron impurities removed.
[0117] Embodiment 24
[0118] This Example 24 provides a method for removing impurity iron in rare earth materials. The difference from Example 23 is that 25 mL of rare earth leaching solution prepared in Preparation Example 4 is used in step S1.
[0119] Results
[0120] The rare earth materials prepared in Examples 1 to 22 were calcined at 1000° C. in an air atmosphere for 3 h and then cooled to room temperature. The iron oxide content was detected and the iron removal rate was calculated. Figures 1 to 6 The iron content in the rare earth leaching solution prepared in Preparation Example 3 and Preparation Example 4 was detected, and the rare earth materials prepared in Example 23 and Example 24 were calcined in an air atmosphere at 1000°C for 3 hours and then cooled to room temperature, and the iron content therein was detected, as shown in FIG. Figure 7 shown.
[0121] from Figure 1 It can be seen that the iron removal rate can be adjusted by adjusting the sublimation temperature of the complex precipitation and the cooling gradient of the cooling temperature zone. Setting the sublimation temperature at 150-160°C is beneficial to the sublimation treatment of the iron complex and the rare earth complex, and the smaller the cooling gradient of the cooling temperature zone, the more conducive it is to the condensation and sublimation separation of the iron complex and the rare earth complex in different cooling temperature zones.
[0122] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.
Claims
1. A method for removing impure iron in rare earth materials, characterized in that: include: Based on the hydrochloric acid optimal solution method, a leachate containing rare earth and iron is obtained, the leachate and the complex solution are stirred and mixed, and then reacted in an environment with a pH of 5-8, water is added to adjust the solubility to precipitate the precipitate, and then the complex precipitate is separated; the complex precipitate is sublimated at a sublimation temperature of 130-160°C in a vacuum environment, and then gradually cooled and condensed in a cooling temperature range of 150-55°C, and the condensed sublimation products within 125-105°C are collected to obtain the rare earth material with impurity iron removed; wherein the sublimation temperature is greater than or equal to the maximum temperature of the cooling temperature range.
2. The removal method according to claim 1, characterized in that: At least one of 2,2,6,6-tetramethyl-3,5-heptanedione, 1,1,1,5,5,5-hexafluoroacetylacetone and 1,1,1-trifluoroacetylacetone is dissolved in the complex solution; and / or the molar ratio of the complex solute in the complex solution to the metal element in the leaching solution is (1-10):1, and the metal element includes rare earth elements and iron elements; and / or the solvent in the complex solution includes an alcohol solvent; and / or the rare earth in the leaching solution includes a lanthanide rare earth, and the lanthanide rare earth includes one of yttrium and europium.
3. The removal method according to claim 1, characterized in that: After the leachate and the complex solution are stirred and mixed, a pH adjuster is added to adjust the pH to 5-8, and the pH adjuster includes one of triethylamine, sodium hydroxide, and sodium methoxide; and / or, after the leachate and the complex solution are stirred and mixed, the reaction is carried out in an environment of pH 5-8 for 2-4 hours; and / or, after the leachate and the complex solution are stirred and mixed, the reaction is carried out in an environment of 25-35°C and pH 5-8.
4. The removal method according to claim 1, characterized in that: After reacting in an environment with a pH of 5-8, water is added in a volume ratio of 1:(1.5-2.5) to the reaction solution and stirred to adjust the solubility; and / or, water is added to adjust the solubility to precipitate, and then the precipitate is allowed to stand at 20-35° C. for 2-4 hours before separation; and / or, after separation, the complex precipitate is obtained by vacuum drying at 50-80° C.
5. The removal method according to claim 1, characterized in that: When obtaining a leachate containing rare earth and iron based on the hydrochloric acid optimal solution method, rare earth materials are stirred in hydrochloric acid for reaction, water is added, and the solvent is evaporated to obtain rare earth chloride, and the rare earth chloride is dissolved in an alcohol solvent to obtain a leachate; the rare earth materials include rare earth and iron.
6. The removal method according to claim 1, characterized in that: The complex precipitate is sublimated at a sublimation temperature of 130-160°C in a vacuum environment for 2-8h; and / or, when gradually cooling and condensing in a cooling temperature section of 150-55°C, the cooling temperature section includes a plurality of cooling temperature zones with decreasing temperature gradients, and the temperature gradients of adjacent cooling temperature zones are independent of each other; and / or, when gradually cooling and condensing in a cooling temperature section of 150-55°C, the temperature of the cooling temperature section decreases linearly; and / or, when gradually cooling and condensing in a cooling temperature section of 150-55°C, the length of the cooling temperature section is 100-150cm.
7. The removal method according to claim 1, characterized in that: The desublimation product collected at 125-105° C. is used to obtain a rare earth material from which impurity iron is removed, and the rare earth material from which impurity iron is removed is subjected to cyclic sublimation and desublimation collection, wherein the number of cycles is 2-5 times; and / or, after the desublimation product collected at 125-105° C. is used to obtain a rare earth material from which impurity iron is removed, the rare earth material from which impurity iron is removed is calcined in an oxygen-containing atmosphere to obtain an oxidized rare earth material from which impurity iron is removed.
8. A removal method according to any one of claims 1 to 5, characterized in that: After the complex precipitate is sublimated at a sublimation temperature of 100-130° C. in a vacuum environment, the residue is collected to obtain the rare earth material from which the impurity iron is removed.
9. The removal method according to claim 8, characterized in that: The complex precipitate is sublimated at a sublimation temperature of 100-130° C. in a vacuum environment for 2-8 hours; and / or, after collecting the residue to obtain the rare earth material from which the impurity iron is removed, the rare earth material from which the impurity iron is removed is subjected to cyclic sublimation and the residue is collected, wherein the number of cycles is 2-5 times; and / or, after collecting the residue to obtain the rare earth material from which the impurity iron is removed, the rare earth material from which the impurity iron is removed is calcined in an oxygen-containing atmosphere to obtain an oxidized rare earth material from which the impurity iron is removed.