CN116377521B - Method for recycling mixed rare earth from NdFeB waste - Google Patents
Method for recycling mixed rare earth from NdFeB waste Download PDFInfo
- Publication number
- CN116377521B CN116377521B CN202211734421.8A CN202211734421A CN116377521B CN 116377521 B CN116377521 B CN 116377521B CN 202211734421 A CN202211734421 A CN 202211734421A CN 116377521 B CN116377521 B CN 116377521B
- Authority
- CN
- China
- Prior art keywords
- rare earth
- chlorinating agent
- roasting
- mixed
- iron boron
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 83
- 238000000034 method Methods 0.000 title claims abstract description 68
- 239000002699 waste material Substances 0.000 title claims abstract description 47
- 229910001172 neodymium magnet Inorganic materials 0.000 title claims abstract description 39
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 36
- 238000004064 recycling Methods 0.000 title abstract description 9
- 239000012320 chlorinating reagent Substances 0.000 claims abstract description 55
- -1 rare earth chloride Chemical class 0.000 claims abstract description 32
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000005660 chlorination reaction Methods 0.000 claims abstract description 20
- 229910001404 rare earth metal oxide Inorganic materials 0.000 claims abstract description 19
- 239000007787 solid Substances 0.000 claims abstract description 18
- 238000005868 electrolysis reaction Methods 0.000 claims abstract description 17
- 238000002386 leaching Methods 0.000 claims abstract description 17
- 238000002156 mixing Methods 0.000 claims abstract description 16
- 150000003839 salts Chemical class 0.000 claims abstract description 16
- 238000001354 calcination Methods 0.000 claims abstract description 12
- 150000001875 compounds Chemical class 0.000 claims abstract description 11
- 238000001914 filtration Methods 0.000 claims abstract description 10
- 239000002131 composite material Substances 0.000 claims abstract description 6
- 239000012716 precipitator Substances 0.000 claims abstract description 5
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 36
- 239000000243 solution Substances 0.000 claims description 26
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 21
- 239000003638 chemical reducing agent Substances 0.000 claims description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 239000000460 chlorine Substances 0.000 claims description 14
- 235000006408 oxalic acid Nutrition 0.000 claims description 12
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 8
- 229910052801 chlorine Inorganic materials 0.000 claims description 8
- 238000001556 precipitation Methods 0.000 claims description 7
- 229910001122 Mischmetal Inorganic materials 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 239000003792 electrolyte Substances 0.000 claims description 6
- 238000007654 immersion Methods 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 239000011259 mixed solution Substances 0.000 claims description 4
- 239000001301 oxygen Substances 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- 238000002791 soaking Methods 0.000 claims description 2
- 238000011084 recovery Methods 0.000 abstract description 15
- 238000000605 extraction Methods 0.000 abstract description 8
- 239000000463 material Substances 0.000 abstract description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 20
- 239000000047 product Substances 0.000 description 20
- 239000002253 acid Substances 0.000 description 12
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 10
- 230000008901 benefit Effects 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 229910052742 iron Inorganic materials 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 239000002244 precipitate Substances 0.000 description 7
- 229910052799 carbon Inorganic materials 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 238000000926 separation method Methods 0.000 description 5
- 239000002351 wastewater Substances 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 3
- 239000008367 deionised water Substances 0.000 description 3
- 229910021641 deionized water Inorganic materials 0.000 description 3
- 238000011978 dissolution method Methods 0.000 description 3
- 238000004134 energy conservation Methods 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 238000007127 saponification reaction Methods 0.000 description 3
- 239000002893 slag Substances 0.000 description 3
- 238000000638 solvent extraction Methods 0.000 description 3
- 230000002195 synergetic effect Effects 0.000 description 3
- MBULCFMSBDQQQT-UHFFFAOYSA-N (3-carboxy-2-hydroxypropyl)-trimethylazanium;2,4-dioxo-1h-pyrimidine-6-carboxylate Chemical compound C[N+](C)(C)CC(O)CC(O)=O.[O-]C(=O)C1=CC(=O)NC(=O)N1 MBULCFMSBDQQQT-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- 229910052779 Neodymium Inorganic materials 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 235000019270 ammonium chloride Nutrition 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000009854 hydrometallurgy Methods 0.000 description 2
- 238000010907 mechanical stirring Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 2
- PLDDOISOJJCEMH-UHFFFAOYSA-N neodymium(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Nd+3].[Nd+3] PLDDOISOJJCEMH-UHFFFAOYSA-N 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 description 2
- 229910052683 pyrite Inorganic materials 0.000 description 2
- 239000011028 pyrite Substances 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 238000003916 acid precipitation Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000002173 cutting fluid Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001180 sulfating effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
- C25C3/34—Electrolytic production, recovery or refining of metals by electrolysis of melts of metals not provided for in groups C25C3/02 - C25C3/32
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/02—Roasting processes
- C22B1/08—Chloridising roasting
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B59/00—Obtaining rare earth metals
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/006—Wet processes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention provides a method for recycling mixed rare earth from neodymium iron boron waste, which comprises the following steps: (1) Mixing neodymium iron boron waste and a solid composite chlorinating agent, and performing selective chlorination roasting to obtain a roasting product; (2) Leaching and separating the roasting product in the step (1) to obtain rare earth chloride solution; (3) Mixing the rare earth chloride solution with a precipitator, filtering and calcining to obtain mixed rare earth oxide; (4) And carrying out molten salt electrolysis on the mixed rare earth oxide to obtain the mixed rare earth. The method utilizes the selectivity of the solid compound chlorinating agent to the rare earth and non-rare earth elements, realizes the efficient extraction of the rare earth elements in the waste materials, completes the efficient recovery and the high-value utilization of the materials, and obtains the mixed rare earth with high purity.
Description
Technical Field
The invention belongs to the technical field of recycling of rare earth permanent magnet waste, and particularly relates to a method for recycling mixed rare earth from neodymium iron boron waste.
Background
The method is not only the largest production country of rare earth permanent magnet materials, but also the largest consumption country and the clean export country. In particular to a sintered NdFeB magnet with excellent magnetic performance, which has the greatest yield and the widest application range. In 2021, the production of sintered NdFeB magnets in China is about 22 ten thousand tons, which accounts for about 90% of the total global production. The utilization of raw materials in its production process is generally only 60-70 wt.%, that is to say about 30-40 wt.% of waste will be produced in its production process. In addition, with the increasing demand of light weight and miniaturization of products in the high and new technical fields, especially in the microelectronics field, the demand of the required magnetic material components is becoming smaller, and blanks can be processed into shapes and sizes meeting the demand through a large amount of machining, so that cutting waste, especially neodymium iron boron sludge waste containing cutting fluid and having higher oxidation degree is increasing. However, it contains about 30wt.% of rare earth elements and has great recovery value. Therefore, the development of the research of green, efficient and high-valued recycling of the NdFeB waste materials can realize the comprehensive utilization of resources, promote the sustainable development of rare earth industry, and have important significance for ecological environment protection and construction of a resource-saving circular economy system.
At present, in the practical application of the domestic industry, rare earth elements are mainly separated and extracted from sintered NdFeB sludge waste by using a traditional hydrometallurgy process, impurities and rare earth are mainly separated by a solvent extraction and precipitation separation method after acid dissolution, and single rare earth is further separated by solvent extraction, so that the aim of recycling rare earth is fulfilled. At present, the wet recovery route of the NdFeB waste mainly comprises a salt total dissolution method, a eugenolysis method, a sulfuric acid double salt precipitation method, an oxalic acid precipitation method, a solvent extraction method and the like.
The full dissolution method and the sulfuric acid double salt precipitation method are both to dissolve the waste completely by using acid, for example, CN1058232A discloses a method for extracting neodymium from neodymium-iron-boron waste, which is to dissolve the waste by using hydrochloric acid; adding oxalic acid solution to generate neodymium oxalate precipitate when the pH value of the solution is adjusted to be 1.5-7 by ammonia or/and heating; the separated neodymium oxalate is heated to a decomposition temperature to obtain neodymium oxide. CN115386722a discloses a method for separating rare earth and iron from pyrite roasting neodymium iron boron waste, which comprises the following steps: mixing neodymium iron boron waste with pyrite, and introducing oxygen to perform selective sulfating roasting; and cooling and grinding the roasted product, and leaching and filtering the product to obtain rare earth leaching liquid and iron concentrate. However, the method has the defects that the acid consumption is large, the alkali consumption during the subsequent neutralization and iron removal is increased, the wastewater amount is increased, and the like.
The hydrochloric acid optimal dissolution method is to leach out rare earth in roasting material preferentially, and Fe which is relatively insoluble in hydrochloric acid 2 O 3 Entering slag phase, such as CN109554549B, discloses a method for recovering rare earth from NdFeB waste by high-temperature high-pressure leaching, wherein NdFeB waste is subjected to oxidative roasting, hydrochloric acid high-temperature high-pressure leaching and Fe in leaching solution 2+ Is subjected to oxidation, impurity removal and purification,obtaining rare earth chloride leaching liquid; the rare earth chloride leaching solution can be used as a subsequent process and a product raw material, rare earth is obtained through extraction and separation, rare earth carbonate is prepared through precipitation, or rare earth oxide is prepared through precipitation-roasting. Although the acid consumption is reduced and the process flow is relatively short in the above method, more hydrochloric acid is still required in the acid leaching process, and a part of iron enters the leaching solution, so that iron removal treatment by purification is required, and a large amount of alkali is required to neutralize the acid wastewater.
In the comprehensive view, the rare earth oxide with higher purity can be obtained by the traditional wet recovery route, but the method has the advantages of long recovery flow, high acid-base consumption, high environmental cost and capability of discharging a large amount of ammonia nitrogen wastewater due to saponification of the extractant, and does not meet the current requirements of environmental protection and energy conservation sustainable development. In addition, the recovery concept of the traditional hydrometallurgy process is basically limited to separating and extracting single rare earth chloride or rare earth oxide from neodymium iron boron waste materials as a final product, and the high-value reutilization of the waste materials to the magnet is not realized.
Therefore, developing a method which has short flow, little pollution and can realize the green and efficient recovery and high-value reutilization of waste is a technical problem to be solved urgently.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a method for recycling mixed rare earth from NdFeB waste. The invention utilizes the selectivity of the solid compound chlorinating agent to rare earth and non-rare earth elements, realizes the efficient extraction of rare earth elements in neodymium iron boron waste materials, obtains high-purity mixed rare earth, and completes the efficient recovery and high-valued utilization of neodymium iron boron waste materials; the method utilizes water immersion to replace acid leaching, reduces acid consumption, shortens process flow, reduces environmental pollution, and has extremely high process operability.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for recovering mischmetal from neodymium iron boron waste, said method comprising the steps of:
(1) Mixing neodymium iron boron waste and a solid composite chlorinating agent, and performing selective chlorination roasting to obtain a roasting product;
(2) Leaching and separating the roasting product in the step (1) to obtain rare earth chloride solution;
(3) Mixing the rare earth chloride solution with a precipitator, filtering and calcining to obtain mixed rare earth oxide;
(4) And carrying out molten salt electrolysis on the mixed rare earth oxide to obtain the mixed rare earth.
According to the invention, neodymium iron boron waste is mixed with a solid composite chlorinating agent and then subjected to selective chlorination roasting, so that rare earth elements are selectively converted into rare earth chlorides which are easily dissolved in water, other impurity elements such as iron enter a slag phase in an oxide or metal state, and a roasting product is subjected to water leaching, precipitation reaction, calcination and molten salt electrolysis to obtain high-purity mixed rare earth, thereby realizing high-value utilization of the neodymium iron boron waste. The method realizes the selective and efficient extraction of rare earth elements through selective chlorination roasting, not only avoids huge acid consumption in the acid leaching process, but also reduces the extraction and separation process in the traditional wet recovery route, shortens the production period, and avoids the ammonia nitrogen wastewater problem caused by the saponification process of the extractant. The method has the advantages of short flow, energy conservation and environmental protection, can realize the green and efficient recovery and high-value reutilization of the waste, and has extremely high process operability.
In the invention, the solid compound chlorinating agent consisting of the main chlorinating agent and the auxiliary chlorinating agent is used as the chlorinating agent, so that the low-melting-point compound chlorinating agent with synergistic effect can be formed, the extraction efficiency of rare earth elements is improved, the chlorination roasting temperature can be reduced, and the low-energy consumption advantage is realized. In addition, compared with the gaseous chlorinating agent such as chlorine, the solid chlorinating agent has the advantages of no toxicity, low cost, easy obtainment and the like.
In the invention, the rare earth chloride solution and Fe can be obtained by adopting the operations of water leaching and separation 2 O 3 The step is low in cost and pollution-free.
Preferably, the chlorine content of the solid compound chlorinating agent in the step (1) is 1 to 4 times of the stoichiometric number, for example, 1 time, 1.5 times, 2 times, 2.5 times, 3 times, 3.5 times or 4 times, based on the total conversion of rare earth contained in the waste neodymium iron boron into rare earth chloride.
In the invention, if the chlorine content in the solid compound chlorinating agent is too large, side reaction is easy to generate, and the cost is increased; if the chlorine content in the solid complex chlorinating agent is too small, insufficient reaction may result.
Preferably, the primary chlorinating agent comprises NH 4 Cl。
Preferably, the secondary chlorinating agent comprises FeCl 2 、AlCl 3 、CoCl 2 、CaCl 2 Or KCl, preferably FeCl 2 。
Preferably, the molar ratio of the primary chlorinating agent to the secondary chlorinating agent is (1-9): 1, which may be, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or the like.
In the invention, if the molar ratio of the main chlorinating agent to the auxiliary chlorinating agent is too small, namely the consumption of the main chlorinating agent is too small, the synergistic effect cannot be achieved, and the auxiliary chlorinating agent may be introduced into the auxiliary reaction; if the molar ratio of the main chlorinating agent to the auxiliary chlorinating agent is too large, that is, the use amount of the main chlorinating agent is too large, the main chlorinating agent is easy to decompose in the re-chlorination roasting, so that the use amount of the chlorinating agent is insufficient and the reaction is insufficient.
Preferably, the neodymium iron boron waste is ground to 50-200 meshes, for example, 50 meshes, 100 meshes, 150 meshes, 200 meshes or the like, before being subjected to selective chlorination roasting.
Preferably, the temperature of the selective chlorination roasting in step (1) is 250-600 ℃, such as 250 ℃, 350 ℃, 450 ℃, 550 ℃, 600 ℃, or the like, preferably 300-400 ℃.
Preferably, the time of the selective chlorination roasting in the step (1) is 2-6h, for example, 2h, 3h, 4h, 5h or 6h, etc.
Preferably, the atmosphere of the selective chlorination roasting in the step (1) is an air atmosphere or an oxygen atmosphere.
Preferably, a reducing agent is also added during the selective chlorination roasting in step (1).
In the invention, the reducing agent is added in the chloridizing roasting process, so that the generation of a by-product (rare earth oxychloride) which is difficult to dissolve in water can be effectively inhibited, and the purity of the product is improved.
Preferably, the reducing agent comprises activated carbon.
The invention is not limited to the macrostructure of activated carbon, and may be exemplified by activated carbon particles or activated carbon powder, etc.
Preferably, the mass fraction of the reducing agent is 5-25%, for example, 5%, 10%, 15%, 20% or 25% based on 100% of the mass of the neodymium iron boron waste.
In the invention, if the mass fraction of the reducing agent is too small, side effects cannot be inhibited; if the mass fraction of the reducing agent is too large, new impurities such as rare earth carbide are easily formed.
Preferably, the temperature of the water immersion in step (2) is 25-70 ℃, and may be, for example, 25 ℃, 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, or the like.
Preferably, the water immersion process in step (2) is accompanied by stirring for a period of 1-4h, for example, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h, etc.
Preferably, the precipitant of step (3) comprises oxalic acid or an oxalic acid solution.
Preferably, the amount of the precipitant in step (3) is 1 to 1.5 times the stoichiometric number, for example 1.1, 1.2, 1.3, 1.4 or 1.5 times, based on the total precipitation of rare earth after mixing the rare earth chloride solution with the precipitant.
Preferably, after the calcined product of step (3) is mixed with the precipitant, the pH of the resulting mixed solution is adjusted to 1 to 3.5, and may be, for example, 1, 1.5, 2, 2.5, 3 or 3.5.
Preferably, the temperature of the calcination in the step (3) is 800-950 ℃, and may be 800 ℃, 820 ℃, 840 ℃, 860 ℃, 880 ℃, 900 ℃, 910 ℃, 920 ℃, 930 ℃, 940 ℃, 950 ℃, or the like, for example.
Preferably, the calcination in step (3) is performed for 1-3 hours, for example, 1 hour, 2 hours, 3 hours, or the like.
Preferably, the electrolyte system in molten salt electrolysis comprises REF 3 -LiF electrolyte system, RE stands for rare earth element, which may be neodymium element or the like, for example.
Preferably, the temperature of the molten salt electrolysis in the step (3) is 980 to 1080 ℃, and may be 980 ℃, 990 ℃, 1000 ℃, 1010 ℃, 1020 ℃, 1030 ℃, 1040 ℃, 1050 ℃, 1060 ℃, 1070 ℃, 1080 ℃, or the like.
As a preferred technical solution, the method comprises the following steps:
(1) Mixing neodymium iron boron waste, a main chlorinating agent, a secondary chlorinating agent and a reducing agent, and chloridizing and roasting for 2-6 hours in an air atmosphere at the temperature of 250-950 ℃ to obtain a roasting product;
wherein the molar ratio of the main chlorinating agent to the auxiliary chlorinating agent is (1-9): 1;
(2) Soaking the roasting product in the step (1) in water at 25-70 ℃ and stirring for 1-4h, and separating to obtain rare earth chloride solution;
(3) Mixing the rare earth chloride solution with a precipitator to obtain a mixed solution with the pH value of 1-3.5, filtering, and calcining at 800-950 ℃ for 1-3 hours to obtain a mixed rare earth oxide;
wherein the dosage of the precipitant is 1-1.5 times of the stoichiometric number;
(4) And carrying out molten salt electrolysis on the mixed rare earth oxide at 980-1080 ℃ to obtain the mixed rare earth.
In a second aspect, the present invention provides the use of a method as described in the first aspect.
The numerical ranges recited herein include not only the recited point values, but also any point values between the recited numerical ranges that are not recited, and are limited to, and for the sake of brevity, the invention is not intended to be exhaustive of the specific point values that the recited range includes.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the invention, by utilizing the different selectivities of the solid composite chlorinating agent to rare earth and non-rare earth elements in the rare earth permanent magnet waste, the rare earth elements are converted into the rare earth chlorides which are easy to dissolve in water, and other elements such as iron and the like basically enter a slag phase in an oxide or metal state, so that the rare earth is efficiently extracted from the neodymium iron boron waste, and the impurity removal efficiency is improved;
(2) The invention provides a low-melting-point solid compound chlorinating agent with synergistic effect, which not only improves the extraction efficiency of rare earth, but also reduces the temperature of chloridizing roasting, and has the advantage of low energy consumption;
(3) The method provided by the invention not only avoids huge acid consumption in the acid leaching process, but also reduces the extraction and separation process in the traditional wet recovery route, shortens the production period, avoids the ammonia nitrogen wastewater problem caused by the saponification process of the extractant, and has the advantages of short flow, energy conservation, environmental protection, less reagent consumption, capability of realizing the green and efficient recovery and high-value recycling of the waste materials, and the like.
(4) The invention has applicability to unoxidized or partially oxidized neodymium iron boron waste, can be recycled in large scale, and has considerable economic and social benefits.
Drawings
Fig. 1 is a process flow chart provided in example 1 of the present invention.
FIG. 2 is a graph showing the thermodynamic parameter change of the chlorination reaction during the selective chlorination roasting process in the method provided by the invention.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Example 1
(1) Firstly, 10g of NdFeB waste material and 3gNH which are ground to 50 meshes are taken 4 Cl、3.5gFeCl 2 Uniformly mixing 1g of active carbon, briquetting, putting into a graphite crucible, putting into a tubular furnace with air atmosphere, performing selective chloridizing roasting, heating the furnace temperature from room temperature to 600 ℃ at a heating rate of 10 ℃/min, preserving heat for 4 hours, and cooling to obtain a roasting product;
wherein the chlorine content of the solid compound chlorinating agent is 2 times of the stoichiometric number, and the main chlorinating agent NH4Cl and the auxiliary chlorinating agent FeCl 2 The mol ratio of (2) to (1), the mass fraction of the reducer activated carbon particles is 10%;
(2) Finely grinding the roasted product, adding the ground product into a 500mL beaker filled with deionized water at 70 ℃ and mechanically stirring for 1h, and filtering and separating to obtain rare earth chloride feed liquid and Fe 2 O 3 A predominantly precipitate;
(3) Adding oxalic acid into the rare earth chloride solution, wherein the dosage of the oxalic acid is 1.5 times of the stoichiometric number, regulating the pH value of the solution to 3.0, and calcining the filtered rare earth oxalate precipitate at 900 ℃ for 2 hours to obtain high-purity mixed rare earth oxide, the purity is about 99.6%, and the recovery rate of rare earth elements is 95.3%;
(4) Molten salt electrolysis is carried out on the mixed rare earth oxide, and an electrolyte system is REF 3 LiF, electrolysis temperature 1000 ℃, obtaining misch metal.
Example 2
(1) Firstly, 5g of NdFeB waste material and 3gNH which are ground to 100 meshes are taken 4 Cl、3.5gFeCl 2 Uniformly mixing 1g of active carbon, briquetting, putting into a graphite crucible, putting into a tube furnace in oxygen atmosphere, performing selective chloridizing roasting, heating the furnace temperature from room temperature to 400 ℃ at a heating rate of 10 ℃/min, preserving heat for 4 hours, and cooling to obtain a roasting product;
wherein the chlorine content of the solid compound chlorinating agent is 1 times of the stoichiometric number, and the main chlorinating agent NH4Cl and the auxiliary chlorinating agent FeCl 2 The mol ratio of (2) to (1), the mass fraction of the reducer activated carbon particles is 10%;
(2) Finely grinding the roasted product, adding the ground product into a 500mL beaker filled with deionized water at 50 ℃ for mechanical stirring for 3 hours, and filtering and separating to obtain rare earth chloride feed liquid with higher purity and Fe 2 O 3 A predominantly precipitate;
(3) Oxalic acid is added into the rare earth chloride solution, the dosage of the oxalic acid is 1.5 times of the stoichiometric number, the pH value of the solution is regulated to 3.0, the rare earth oxalate precipitate obtained by filtering is calcined for 3 hours at 800 ℃, the high-purity mixed rare earth oxide is obtained, the purity is about 99.5%, and the recovery rate of rare earth elements is 95.6%.
(4) Molten salt electrolysis is carried out on the mixed rare earth oxide, and the electrolysis is carried outThe mass system is REF 3 LiF, electrolysis temperature 980 ℃, obtaining misch metal.
Example 3
(1) Firstly, 10g of NdFeB waste material and 3gNH which are ground to 150 meshes are taken 4 Cl、3.5gFeCl 2 、3.7gAlCl 3 Mixing with 2g of active carbon uniformly, briquetting, placing into a graphite crucible, placing into a tube furnace for selective chloridizing roasting, heating the furnace temperature from room temperature to 600 ℃ at a heating rate of 10 ℃/min, preserving heat for 4 hours, and cooling to obtain a roasting product;
wherein the chlorine content of the solid compound chlorinating agent is 4 times of the stoichiometric number, and the main chlorinating agent is NH 4 Cl and a side chlorinating agent (FeCl) 2 And AlCl 3 ) The mol ratio of the active carbon particles of the reducing agent is 1:1, and the mass fraction of the active carbon particles of the reducing agent is 20%;
(2) Finely grinding the roasted product, adding the ground product into a 500mL beaker filled with deionized water at 25 ℃ for mechanical stirring for 4 hours, and filtering and separating to obtain rare earth chloride feed liquid with higher purity and Fe 2 O 3 A predominantly precipitate;
(3) Adding oxalic acid into the rare earth chloride solution, wherein the dosage of the oxalic acid is 1.4 times of the stoichiometric number, regulating the pH value of the solution to 2.5, and calcining the filtered rare earth oxalate precipitate at 950 ℃ for 1h to obtain high-purity mixed rare earth oxide, the purity is about 99.7%, and the rare earth recovery rate is 95.0%;
(4) Molten salt electrolysis is carried out on mixed rare earth oxide serving as a raw material, and an electrolyte system is REF 3 LiF, electrolysis temperature 1080 ℃, obtaining misch metal.
Fig. 1 shows a process flow diagram for preparing misch metal of examples 1-3.
Fig. 2 shows a graph of thermodynamic parameters of the chlorination reaction during selective chlorination roasting in the method provided by the present disclosure.
The applicant states that the process of the invention is illustrated by the above examples, but the invention is not limited to, i.e. does not mean that the invention must be carried out in dependence on the above process steps. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of selected raw materials, addition of auxiliary components, selection of specific modes, etc. fall within the scope of the present invention and the scope of disclosure.
Claims (19)
1. A method for recovering mischmetal from neodymium iron boron waste, the method comprising the steps of:
(1) Mixing neodymium iron boron waste and a solid composite chlorinating agent, and carrying out selective chlorination roasting at the roasting temperature of 250-600 ℃ to obtain a roasting product;
wherein the solid compound chlorinating agent comprises a main chlorinating agent and a secondary chlorinating agent with the mol ratio of (1-9): 1; the main chlorinating agent comprises NH 4 Cl; the secondary chlorinating agent comprises FeCl 2 、AlCl 3 、CoCl 2 、CaCl 2 Or KCl, or any one or a combination of at least two thereof;
(2) Leaching and separating the roasting product in the step (1) to obtain rare earth chloride solution;
(3) Mixing the rare earth chloride solution with a precipitator, filtering and calcining to obtain mixed rare earth oxide;
(4) And carrying out molten salt electrolysis on the mixed rare earth oxide to obtain the mixed rare earth.
2. The method of claim 1, wherein the chlorine content of the solid composite chlorinating agent in step (1) is 1-4 times the stoichiometric number, based on the total conversion of rare earth contained in the scrap neodymium iron boron to rare earth chloride.
3. The method according to claim 1, wherein the secondary chlorinating agent is feci 2 。
4. The method of claim 1, wherein the neodymium iron boron waste is ground to 50-200 mesh prior to the selective chlorination roasting.
5. The method of claim 1, wherein the selective chlorination roasting of step (1) is for a period of 2 to 6 hours.
6. The method of claim 1, wherein the atmosphere of the selective chlorination roasting of step (1) is an air atmosphere or an oxygen atmosphere.
7. The method of claim 1, wherein a reducing agent is also added during the selective chlorination roasting of step (1).
8. The method of claim 7, wherein the reducing agent comprises activated carbon.
9. The method according to claim 7, wherein the mass fraction of the reducing agent is 5-25% based on 100% of the mass of the neodymium iron boron waste.
10. The method of claim 1, wherein the water immersion in step (2) is at a temperature of 25-70 ℃.
11. The method of claim 1, wherein the water immersion of step (2) is accompanied by stirring for a period of 1-4 hours.
12. The method of claim 1, wherein the precipitant of step (3) comprises oxalic acid or an oxalic acid solution.
13. The method of claim 1, wherein the amount of the precipitant used in step (3) is 1 to 1.5 times the stoichiometric amount, based on complete precipitation of the rare earth after mixing the rare earth chloride solution with the precipitant.
14. The method according to claim 1, wherein after the rare earth chloride solution of step (3) is mixed with the precipitant, the pH of the resulting mixed solution is adjusted to 1 to 3.5.
15. The method of claim 1, wherein the temperature of the calcining of step (3) is 800-950 ℃.
16. The method of claim 1, wherein the calcination in step (3) is for a period of 1 to 3 hours.
17. The method of claim 1, wherein the electrolyte system in molten salt electrolysis comprises REF 3 -LiF electrolyte system, RE representing rare earth element.
18. The method of claim 1 wherein the temperature of molten salt electrolysis in step (3) is 980-1080 ℃.
19. The method according to claim 1, characterized in that it comprises the steps of:
(1) Mixing neodymium iron boron waste, a main chlorinating agent, a secondary chlorinating agent and a reducing agent, and chloridizing and roasting for 2-6 hours in an air atmosphere at the temperature of 250-600 ℃ to obtain a roasting product;
wherein the molar ratio of the main chlorinating agent to the auxiliary chlorinating agent is (1-9): 1;
(2) Soaking the roasting product in the step (1) in water at 25-70 ℃ and stirring for 1-4h, and separating to obtain rare earth chloride solution;
(3) Mixing the rare earth chloride solution with a precipitator to obtain a mixed solution with the pH value of 1-3.5, filtering, and calcining at 800-950 ℃ for 1-3 hours to obtain a mixed rare earth oxide;
wherein the dosage of the precipitant is 1-1.5 times of the stoichiometric number;
(4) And carrying out molten salt electrolysis on the mixed rare earth oxide at 980-1080 ℃ to obtain the mixed rare earth.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211734421.8A CN116377521B (en) | 2022-12-30 | 2022-12-30 | Method for recycling mixed rare earth from NdFeB waste |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211734421.8A CN116377521B (en) | 2022-12-30 | 2022-12-30 | Method for recycling mixed rare earth from NdFeB waste |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116377521A CN116377521A (en) | 2023-07-04 |
| CN116377521B true CN116377521B (en) | 2024-04-16 |
Family
ID=86962221
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211734421.8A Active CN116377521B (en) | 2022-12-30 | 2022-12-30 | Method for recycling mixed rare earth from NdFeB waste |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116377521B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08291346A (en) * | 1995-02-21 | 1996-11-05 | Sumitomo Metal Mining Co Ltd | Method for recovering rare earth element from scrap and production of rare earth-transition metal alloy powder |
| JP2000144276A (en) * | 1998-11-10 | 2000-05-26 | Agency Of Ind Science & Technol | Recovering method for rare earth element and cobalt |
| CN1935658A (en) * | 2006-09-25 | 2007-03-28 | 包头市图南稀土有限责任公司 | Method for producing chlorinated rare earth by decomposing and mixing rare earth headings using calcination of ammonia chloride |
| CN102011020A (en) * | 2009-12-14 | 2011-04-13 | 包头市玺骏稀土有限责任公司 | Method for recovering rare earth elements from neodymium-iron-boron wastes |
| CN109554549A (en) * | 2019-01-24 | 2019-04-02 | 内蒙古科技大学 | The method that high temperature and pressure leaches rare earth in recycling neodymium iron boron waste material |
| CN110607537A (en) * | 2019-09-26 | 2019-12-24 | 江西理工大学 | Method for synchronously and efficiently extracting rare earth and iron from high-value recycled neodymium iron boron waste |
| CN111187927A (en) * | 2020-02-18 | 2020-05-22 | 内蒙古科技大学 | Method for selectively sulfating and recovering rare earth in neodymium iron boron waste |
| CN113667824A (en) * | 2021-07-15 | 2021-11-19 | 江西理工大学 | Method for separating rare earth and iron from neodymium iron boron waste material with high selectivity |
-
2022
- 2022-12-30 CN CN202211734421.8A patent/CN116377521B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08291346A (en) * | 1995-02-21 | 1996-11-05 | Sumitomo Metal Mining Co Ltd | Method for recovering rare earth element from scrap and production of rare earth-transition metal alloy powder |
| JP2000144276A (en) * | 1998-11-10 | 2000-05-26 | Agency Of Ind Science & Technol | Recovering method for rare earth element and cobalt |
| CN1935658A (en) * | 2006-09-25 | 2007-03-28 | 包头市图南稀土有限责任公司 | Method for producing chlorinated rare earth by decomposing and mixing rare earth headings using calcination of ammonia chloride |
| CN102011020A (en) * | 2009-12-14 | 2011-04-13 | 包头市玺骏稀土有限责任公司 | Method for recovering rare earth elements from neodymium-iron-boron wastes |
| CN109554549A (en) * | 2019-01-24 | 2019-04-02 | 内蒙古科技大学 | The method that high temperature and pressure leaches rare earth in recycling neodymium iron boron waste material |
| CN110607537A (en) * | 2019-09-26 | 2019-12-24 | 江西理工大学 | Method for synchronously and efficiently extracting rare earth and iron from high-value recycled neodymium iron boron waste |
| CN111187927A (en) * | 2020-02-18 | 2020-05-22 | 内蒙古科技大学 | Method for selectively sulfating and recovering rare earth in neodymium iron boron waste |
| CN113667824A (en) * | 2021-07-15 | 2021-11-19 | 江西理工大学 | Method for separating rare earth and iron from neodymium iron boron waste material with high selectivity |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116377521A (en) | 2023-07-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103374652B (en) | Method for comprehensively recycling rare earth and fluorine in process of treating bastnaesite | |
| CN102206755B (en) | Method for separating and recovering valuable elements from neodymium-iron-boron wastes | |
| CN103540756B (en) | A kind of method processing waste and old neodymium iron boron material dissolution rare earth | |
| CN112522527B (en) | Electrolytic-based method for selectively recovering rare earth elements from Nd-Fe-B magnet scrap | |
| CN114105171B (en) | Method for comprehensively utilizing lepidolite resources and lithium hydroxide prepared by method | |
| CN104928475B (en) | A kind of recovery method of the aluminium scrap silicon containing rare earth | |
| CN101392332B (en) | Cleaning production technique for directly transforming rare earth sulfate bake ore to extract rare earth | |
| CN104928504B (en) | A kind of recovery method of aluminium scrap silicon middle rare earth | |
| CN106848473B (en) | Method for selectively recovering lithium in waste lithium iron phosphate batteries | |
| CN113279048B (en) | Method for preparing high-purity iron phosphate from iron-containing slag | |
| CN107502744B (en) | A kind of processing method of high lead barium silver separating residues | |
| WO2012171481A1 (en) | Hydrometallurgical process for complete and comprehensive recovery with substantially no wastes and zero emissions | |
| CN102154553B (en) | Method for removing iron and aluminum by autoxidation of iron-based waste material containing high-value elements | |
| CN105567985A (en) | Recovery method of rare earth metal electrolysis fused salt slag | |
| CN104388711A (en) | Method for recovering rare earth by leaching rare earth oxide molten slag | |
| CN111187927A (en) | Method for selectively sulfating and recovering rare earth in neodymium iron boron waste | |
| CN113149075A (en) | Method for preparing niobium pentoxide from low-grade niobium ore | |
| CN116377521B (en) | Method for recycling mixed rare earth from NdFeB waste | |
| CN110055425B (en) | Electroplating sludge heavy metal recycling method | |
| CN111349798A (en) | Neodymium iron boron waste recycling system and method | |
| CN112877541B (en) | Recycled alloy prepared based on neodymium iron boron oil sludge and preparation method thereof | |
| CN113005304A (en) | Method for recovering bismuth from bismuth oxychloride waste | |
| CN117512340A (en) | Recovery method of NdFeB waste material, permanent magnetic ferrite and regenerated rare earth permanent magnetic material | |
| CN115141942B (en) | Method for recovering rare earth from neodymium iron boron waste and separating main element iron and application of method in preparation of soft magnetic ferrite serving as raw material | |
| CN114525408B (en) | Method for combined treatment of waste lithium cobalt oxide anode material and tungsten-containing solid waste |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant |