Selective recovery method for rare earth elements (REE) from used neodymium iron boron (NdFeB) magnets

Abstract

A method for selectively recovering rare earth elements (REEs) from used neodymium iron boron (NdFeB) magnets is provided, and this method is... (a) A process of demagnetizing a neodymium iron boron (NdFeB) magnet, pulverizing it into fine powder / milling it, and subjecting the resulting magnet powder to aeration leaching, (b) Aeration leaching of the magnet powder is performed in order to dissolve REE as a rare earth salt, and during the aeration leaching, Fe 2+ From Fe 3+ A step of generating a mother liquor containing rare earth salts by completely precipitating iron as iron oxide and / or iron hydroxide by-products based on oxidation to, and subsequently, (c) The filtered mother liquor is reacted with oxalic acid to precipitate rare earth elements as rare earth oxalates, and further calcined to obtain rare earth oxides for recovering rare earth elements (REE) from the rare earth oxides, the method having the advantage of low acid consumption, low capital costs and reagent consumption, and simultaneously producing iron oxide and / or iron hydroxide as by-products.

Description

[Technical Field]

[0001] Field of Invention This invention provides a method for selectively recovering rare earth elements (REE) from used neodymium iron boron (NdFeB) magnets, and this method is... (a) A process of demagnetizing a neodymium iron boron (NdFeB) magnet, pulverizing / milling the magnet powder, and subjecting the resulting magnet powder to aeration leaching, (b) The magnet powder is subjected to aeration leaching in order to selectively dissolve REE as a rare earth salt, and during the aeration leaching, Fe 2+ From Fe 3+ A step of generating a mother liquor containing rare earth salts by completely precipitating iron as iron oxide and / or iron hydroxide by-products based on oxidation to, and subsequently, (c) The filtered mother liquor is reacted with oxalic acid to precipitate rare earth elements as rare earth oxalates, and further calcined to obtain rare earth oxides for recovering rare earth elements (REE) from rare earth oxides. The method of the present invention is advantageous in that it can selectively recover rare earth elements (REE) from used neodymium iron boron (NdFeB) magnets, and is advantageous in that it consumes less acid, has low capital costs and reagent consumption, and simultaneously produces iron oxide and / or iron hydroxide as by-products. [Background technology]

[0002] NdFeB magnets are the most common permanent magnets, used in many industries due to their strong magnetic properties. Today, the increasing waste problem and the rapid depletion of rare earth element resources have made the recycling of used NdFeB magnets significantly more important, while requiring specialized workspace. REE can be recovered from magnet scrap through several recycling techniques, including hydrogen decrepitation, chemical vapor transport, aeriometallurgy, high-temperature metallurgy, electrometallurgy, and hydrometallurgy. Hydrometallurgy is the most common of these. In this method, NdFeB magnet scrap is completely or selectively dissolved in a strong mineral or organic acid, and the desired REE is selectively precipitated as a double sulfate, oxalate, or fluoride. Selectivity and reaction rate are major challenges in this recycling method. While wet metallurgy is the best method for recovering substantial amounts of REE, it requires expensive pretreatment techniques, consumes large amounts of chemicals, inevitably causing environmental problems, and involves multiple steps, resulting in a long overall process time. Another common method for recovering REE from magnetic scrap is selective leaching after oxidation at high temperatures, but this method causes environmental pollution due to the oxidation roasting process, and the high-temperature oxidation roasting in this method is long, leading to high capital costs.

[0003] The references are as follows: Liu et al. [Liu, Z. et al. Separation and coextraction of REEs and Fe from NdFeB sludge by co-leaching and stepwise precipitation. Sep. Purif. Technol. 282, 119795 (2022)] recovered REE from NdFeB sludge by co-leaching REE and Fe using hydrochloric acid as the leaching medium after pretreatment. In this method, the magnetic sludge is completely dissolved in the hydrochloric acid during leaching, resulting in high energy and acid consumption. Rabatho et al. [Rabatho, JP, Tongamp, W., Takasaki, Y., Haga, K. & Shibayama, A Recovery of Nd and Dy from rare earth magnetic waste sludge by hydrometallurgical process. J. Mater. Cycles Waste Manag. 15, 171-178 (2013)] investigated the possibility of dissolving high concentrations of Nd (35%) in magnetic waste sludge by leaching using an acidic solution of HNO3 and H2O2. The subsequent steps involved precipitation by pH adjustment with the addition of NaOH and Fe removal by filtration. The final recovery rates using this method were 69.7% for Nd and 51% for Dy, and the purity of the final product, Nd2O3, was higher than 68.0%.

[0004] A prior patent document (CN114574702A) discloses a method for recovering rare earth elements from recycled neodymium iron boron material. In this method, hydrogen peroxide is used as a leaching agent and hydrochloric acid leaching is used to dissolve the rare earth elements in the feed solution, but both iron and boron remain in the slag and are not dissolved. Although the recovery rate of rare earth elements is high, the consumption of hydrochloric acid, hydrogen peroxide, and ammonia water is high, which directly leads to increased energy consumption and costs.

[0005] Considering the above, this technology needs to provide a method for selectively recovering rare earth elements (REE) from used neodymium iron boron (NdFeB) magnets that is easy, low-cost, has low capital costs, consumes little acid and reagents, and can produce iron oxide and / or iron hydroxide by-products.

[0006] Object of the invention Therefore, the main objective of the present invention is to provide a simple and low-cost method for the selective recovery of rare earth elements (REE) from used neodymium iron boron (NdFeB) magnets.

[0007] Another object of the present invention is to provide a method that reduces capital costs, acid consumption, and reagent consumption.

[0008] A further object of the present invention is to provide the method for providing iron oxide and / or iron hydroxide by-products.

[0009] Summary of the Invention Accordingly, in a basic embodiment of the present invention, a method for selectively recovering rare earth elements (REEs) from used neodymium iron boron (NdFeB) magnets is provided, the method comprising the following steps: (a) A process of demagnetizing a neodymium iron boron (NdFeB) magnet, pulverizing it into fine powder / milling it, and then subjecting the resulting magnet powder to aeration leaching; (b) Aeration leaching of the magnet powder is performed in order to selectively dissolve REE as a rare earth salt, and during the aeration leaching, Fe 2+ From Fe 3+ A process to produce a mother liquor containing rare earth chlorides by completely precipitating iron as an iron oxide / iron hydroxide by-product based on oxidation to iron; (c) A step of reacting the filtered mother liquor with oxalic acid to precipitate rare earth elements as rare earth oxalates, and further calcining to obtain rare earth oxides and / or hydroxides for recovering rare earth elements (REE) from rare earth oxides and / or hydroxides.

[0010] Preferably, in the method for selectively recovering rare earth elements (REE), step (a) includes demagnetizing a neodymium iron boron (NdFeB) magnet by a method that includes applying an external magnetic field and mechanical shock treatment at a temperature exceeding the Curie temperature (400-500°C) for 1 hour until the magnetic properties disappear; subsequently, pulverizing the demagnetized material to a size of less than 500 μm based on mechanical pulverization such as hydrogenation and / or grinding and ball milling to obtain the magnet powder with increased surface area; and sieving this powder to obtain both undersize and oversize powder.

[0011] In another preferred embodiment of the present invention, a method for selectively recovering rare earth elements (REE) is provided, wherein step (b) involves aeration leaching by selectively dissolving the REE as rare earth salts, wherein the sieved and sieved magnetic powders are added to water and acid, and both the REE and the ferrous / ferric salts are leached in the presence of air at a pH range of 1 to 7, a leaching temperature range of 20 to 40°C to 100°C, and a stirring speed of 5 to 2000 rpm for 1 to 12 hours to recover the rare earth salts and ferrous salts. The method involves providing a solution in which the ferrous salt reacts with dissolved oxygen in the air, oxygen enriched in the air, or oxygen or ozone to convert it to a ferric salt, which is unstable in the pH range and dissociates into iron oxide and / or iron hydroxide to release acid, which further reacts with undissolved magnet powder, and by continuing aeration leaching until the magnet powder is completely consumed, a desired mother liquor containing a rare earth salt and a residue containing iron oxide and / or iron hydroxide as byproducts is obtained in a yield of more than 90%.

[0012] Preferably, in the selective recovery method for rare earth elements (REE), in step (b), the magnetic powder and acid are supplied in a ratio of 1:2 to 1:100, and the acid includes organic acids and inorganic acids.

[0013] More preferably, in the method for selectively recovering rare earth elements (REE), step (c) is to remove a negligible amount of Fe, which is a residue containing iron oxide and / or iron hydroxide. 2+The method includes reacting a filtered mother liquor containing [a certain substance] with oxalic acid to precipitate rare earth elements (REE) in the form of rare earth oxalates, and then calcining these in air at 800°C to obtain rare earth oxides.

[0014] In another preferred embodiment of the selective recovery method for rare earth elements (REE), the acid concentration during leaching in step (b) is sufficiently high to initiate iron precipitation and sufficiently low to maintain the rare earth elements in the solution within the pH range of 1 to 6.

[0015] Preferably, the selective recovery method for rare earth elements (REE) can reduce the amount of acid consumed to selectively recover rare earths from the magnet and achieve a REE yield of 99% and a purity of 99% (see this method).

[0016] More preferably, in the selective recovery method for rare earth elements (REE), the spent neodymium iron boron (NdFeB) magnets include consumer scrap and residues (magnetic shavings, defective magnets, REE-containing residues from metal manufacturing, electric arc furnace residues, industrial residues, etc.), or spent products consisting of small fluorescent lamps, LEDs, LCD backlights, plasma screens, cathode ray tubes, magnets, automobiles (motor magnets, switches, sensors, actuators), mobile phones (speakers, switches), hard disk drives (HDDs), consumer electrical and electronic equipment, electric vehicles and hybrid vehicles, wind turbines, nickel metal halide batteries, and catalysts.

[0017] Accordingly, one aspect of the present invention provides a method for recovering REE from a secondary source of NdFeB permanent magnets. This method includes converting the magnet material into a high surface area form, treating the converted magnet material with an acidic aqueous solution in the presence of an oxygen (air) stream to selectively leach out REE and obtain a leaching slurry, and filtering the leaching slurry to separate the noble liquid from the residue, and then treating the noble liquid with an arbitrary precipitating agent to obtain REE.

[0018] Secondary sources of NdFeB magnets include consumer scrap and residues (magnetic shavings, defective magnets, REE-containing residues during metal production, electric arc furnace residues, industrial residues, etc.), or used products consisting of small fluorescent lamps, LEDs, LCD backlights, plasma screens, cathode ray tubes, magnets, automobiles (magnets for motors, switches, sensors, actuators), mobile phones (speakers, switches), hard disk drives (HDDs), household electrical and electronic devices, electric and hybrid vehicles, wind turbines, nickel metal hydride batteries, and catalysts.

[0019] In another aspect, demagnetization is achieved by exposing the magnetic material to a temperature above the Curie temperature (400 - 500 °C) (where magnetic properties are lost), applying an external magnetic field, or subjecting it to mechanical shock treatment.

[0020] In another aspect, the surface area is increased by grinding and sample preparation (using hydrogen atomization and / or grinding or milling to mechanically pulverize the magnetic material into powder).

[0021] In yet another aspect, sieving and size mixing (sieving the neodymium iron boron powder obtained in the second step through a sample separation screen) yields powders below and above the sieve.

[0022] In yet another aspect, leaching is performed by adding water and acid or ferrous / ferric salts to the powder below the sieve at a pH of 1 - 7, a leaching temperature from room temperature to 100 °C, a stirring speed of 5 - 2000 rpm, and a leaching time in the range of 1 - 12 hours.

[0023] In yet another aspect, the ratio of the REE-containing compound to water and acid or ferrous / ferric salts is 1:2 - 1:100. This method further includes converting ferrous ions to ferric by aeration with air / oxygen / ozone, and ferric ions are insoluble at a given pH and thus precipitate from the solution.

[0024] In yet another embodiment, the leaching slurry is filtered to separate the mother liquor containing rare earth salts from the residue containing iron oxide and / or iron hydroxide, and the rare earth elements are then precipitated from the filtered solution by oxalic acid precipitation, followed by calcination to produce rare earth oxide compounds. [Brief explanation of the drawing]

[0025] [Figure 1] Figure 1: A flowchart showing the processing route for recovering rare earth elements from used magnets. [Figure 2] Figure 2: Shows the superimposed Pourbaix diagram of the Fe-H2O system and the Nd-H2O system. [Figure 3] Figure 3: Images of leaching tests with and without an oxidizing agent are shown. [Figure 4] Figure 4: X-ray diffraction patterns of rare earth oxides are shown. [Figure 5] Figure 5: Energy-dispersive X-ray diffraction (EDAX) analysis of rare earth oxides is shown. [Figure 6] Figure 6: X-ray diffraction pattern of leached residue. [Modes for carrying out the invention]

[0026] Detailed description of the present invention As described above, the present invention provides a method for selectively recovering rare earth elements (REE) from used neodymium iron boron (NdFeB) magnets, the method comprising: (a) demagnetizing the neodymium iron boron (NdFeB) magnets and subjecting the magnet powder, after being pulverized / milled, to aeration leaching; and (b) performing aeration leaching of the magnet powder to dissolve the REE as rare earth chlorides, wherein Fe 2+ From Fe 3+A step of generating a mother liquor containing rare earth chloride by completely precipitating iron as iron oxide / hydroxide by-products based on oxidation thereto, and subsequently, (c) reacting the filtered mother liquor with oxalic acid to precipitate rare earth elements as rare earth oxalates, and further calcining to obtain rare earth oxides for recovering rare earth elements (REE) from the rare earth oxides. This method can advantageously selectively recover rare earth elements (REE) from used neodymium iron boron (NdFeB) magnets. Advantageously, it has low acid consumption, low capital cost and reagent consumption, and simultaneously produces iron oxide and / or iron hydroxide as by-products.

[0027] Therefore, the present invention relates to the selective recovery of rare earth elements (REE) from used NdFeB magnets. Leaching the magnet powder and taking advantage of the fact that Fe 2+ remains in a solution with a pH less than 7 without precipitation, Fe 2+ is oxidized to Fe 3+ . Further, this method includes filtering the leaching slurry to separate, respectively, a mother liquor and a residue containing rare earth salts and iron oxide and / or iron hydroxide. Precipitating the rare earth salts as rare earth oxalates and then calcining yields rare earth oxide compounds. This method not only reduces the acid consumption during the selective recovery of rare earth elements but also regenerates the acid for leaching. Therefore, the method of the present invention consumes only oxalic acid.

[0028] In step (a), the magnet containing rare earth elements is demagnetized at a temperature exceeding 300 °C for 1 hour, and then the demagnetized material is pulverized to a size less than 90 μm.

[0029] In step (b), the material obtained in step (a) is added to water and acid / ferrous salt / ferric salt and leached for 1 to 12 hours at a pH range of 1 to 7 and a leaching temperature range of room temperature to 100°C. During acid leaching, both the rare earth elements and iron from the magnet dissolve in the form of rare earth salts and ferrous salts. Since the leaching operation was carried out in the presence of air, dissolved oxygen reacts with the ferrous salt to convert it into ferric salt. The ferric salt is not stable at a given pH and dissociates into iron oxide and / or iron hydroxide, releasing acid. The acid further reacts with any undissolved magnet to dissolve the rare earth elements and iron. This process continues until the rare earth elements are completely dissolved or the acid is completely consumed. During leaching, the acid concentration must be high enough to initiate the precipitation of iron and low enough to retain the rare earth elements in the solution (pH 2 to 6), which can be shown in Figure 2. The reactions that occur during leaching are as follows: [ka]

[0030] As a result, a noble liquid containing rare earth salts and a residue containing iron oxide and / or iron hydroxide are obtained.

[0031] The Fe contained in the mother liquor obtained in step (b) 2+ Since this is almost negligible, the mixture is sent to the precipitation step (c), where the noble liquid containing the rare earth salts is reacted with oxalic acid to precipitate the rare earth elements in the form of rare earth oxalates, as shown in formula (6) below. [ka]

[0032] The aforementioned rare earth oxalate is calcined in air at 800°C to obtain a rare earth oxide as shown in formula (7) below. [ka]

[0033] The method of the present invention not only reduces the consumption of leaching acid but also reduces the consumption of reagents for the precipitation process. This method also avoids energy-intensive high-temperature oxidation processes required for the selective recovery of rare earth elements from magnets. Furthermore, this method can recover approximately 99% of 99% pure REE. A flowchart of this method is shown in Figure 1.

[0034] The unique method of the present invention makes the following possible: Selective dissolution of REE by aeration leaching, A closed-loop process involving only oxalic acid consumption.

[0035] The non-obviousness of the present invention lies in the fact that the method of the present invention uses aeration leaching to Fe 2+ Fe 3+ This invention relates to the complete precipitation of iron from a solution by oxidation, thereby obtaining iron oxide and / or iron hydroxide as by-products.

[0036] The selective advantages of the present invention as an improved version of existing methods are based on the following method characteristics: Low acid consumption, Low cost of capital, Low reagent consumption, Iron oxide by-products. [Examples]

[0037] Example 1 In a preferred method of the present invention, 5 g of finely powdered magnetic powder (having a composition of 64.40% iron, 25.60% neodymium, 0.92% dysprosium, 3.72% praseodymium, 1.66% chromium, 1.03% cobalt, 0.91% nickel, and 0.34% aluminum by weight) is added in a 10:1 ratio to water and HCl in a 500 mL three-necked flask heated on a hot plate magnetic stirrer to maintain the flask temperature within ±1°C. The leaching time is 1 to 12 hours, the pH is 3 to 7, the leaching temperature is in the range of room temperature to 90°C, and the stirring speed is 600 rpm. During the experiment, the volume of the solution was kept constant by connecting a condenser to one of the three necks to suppress water evaporation. An air pump was connected to the other neck to supply oxygen, and Fe 2+ Fe 3+ It was oxidized. As shown in Figure 2, in solutions with a pH of less than 7, Fe 2+ Since it does not precipitate and remains in the solution, the magnetic powder leaches out, Fe 2+ Fe 3+ The slurry was oxidized. The flask was continuously stirred using a magnetic stirring rod to ensure uniformity of the slurry. The pH and oxidation-reduction potential (ORP) of the slurry were measured every hour. The slurry was filtered using a gouch crucible and a vacuum filtration system, and the filtrate was then titrated with potassium permanganate solution to measure the iron content. Images of the residue with and without the AIM pump are shown in Figure 3. A positive ORP value ensured that the iron was beginning to oxidize, and when the ORP reached +200mV, the observed iron content was negligible. The leaching experiment was stopped when the iron content became negligible, and the slurry was filtered using filter paper. Next, this leachate was mixed with oxalic acid to precipitate REE in the form of rare earth oxalates. Furthermore, these rare earth oxalates were calcined at 850°C for 1 hour to produce rare earth oxides. The REE recovered in the final product was approximately 99% rare earth oxides. The XRD patterns and SEM-EDAX analysis results are shown in Figures 4 and 5, respectively. The XRD pattern of the leachate residue is shown in Figure 6.

[0038] Example 2 In a three-necked flask, 5 g of magnetic powder was combined with 50 mL of a stoichiometric solution of hydrochloric acid (for rare earth elements and other elements besides iron) at 90°C and 600 rpm. The flask was placed on a hot-plate magnetic stirrer, and the solution was continuously stirred using a magnetic stirring rod to ensure homogeneity. During the experiment, a condenser was connected to one of the flask's necks to control water evaporation and maintain a constant solution volume. An air pump was connected to the other neck of the flask to supply oxygen and oxidize the iron in the solution. Every hour, the solution was taken out with a micropipette, and the pH and Eh were checked with a pH-ORP combination meter. Then, 1 mL of the solution was filtered using a Gauch crucible, and the remaining solution was combined with the slurry. After the resulting residue was properly washed and dried, the phases present in the residue were examined using X-ray diffraction. If the ORP showed +200 mV, iron was not present in the slurry, so an excess amount of acid was added to dissolve the other elements contained in the magnetic powder. The leached liquid was mixed with oxalic acid to obtain a dilute oxalate, which was then calcined at 800°C to obtain rare earth oxides. REE was recovered in the final product, and approximately 99% of it consisted of rare earth oxides.

[0039] Example 3 As described in Example 1, a leaching experiment was conducted using 5 g of finely powdered magnet powder (composed of 58.67% iron, 11.23% neodymium, 21.84% cerium, 2.74% praseodymium, 2.69% gadolinium, 0.69% nickel, and 0.60% aluminum by weight). 98% of the REE recovered in the final product was rare earth oxides.

[0040] Accordingly, the advances of the present invention make it possible to provide an approach for the selective recovery of rare earth elements (REEs) from used neodymium iron boron (NdFeB) magnets, which is advantageous in that it consumes less acid, has low capital and reagent costs, and simultaneously produces iron oxide and / or iron hydroxide as byproducts.

Claims

1. A method for selectively recovering rare earth elements (REEs) from used neodymium iron boron (NdFeB) magnets, comprising the following steps: (a) A process of demagnetizing a neodymium iron boron (NdFeB) magnet, pulverizing it into fine powder / milling it, and then subjecting the resulting magnet powder to aeration leaching; (b) The magnet powder is subjected to aeration leaching in order to selectively dissolve REE as a rare earth salt, and during the aeration leaching, Fe 2+ From Fe 3+ A process to produce a mother liquor containing rare earth chlorides by completely precipitating iron as an iron oxide / iron hydroxide by-product based on oxidation to iron; (c) A step of reacting the filtered mother liquor with oxalic acid to precipitate rare earth elements as rare earth oxalates, and further calcining to obtain rare earth oxides and / or rare earth hydroxides for recovering rare earth elements (REE) from rare earth oxides and / or rare earth hydroxides. Methods that include...

2. A method for selectively recovering rare earth elements (REEs) according to claim 1, wherein step (a) includes demagnetizing a neodymium iron boron (NdFeB) magnet by a method encompassing the application of an external magnetic field and mechanical shock treatment at a temperature exceeding the Curie temperature (400 to 500°C) for 1 hour until the magnetic properties disappear, and subsequently pulverizing the demagnetized material to a size of less than 500 μm based on mechanical pulverization including hydrogenation and / or grinding and ball milling to obtain the magnet powder with increased surface area, and sieving therebefore obtaining both the under-sieved and over-sieved powders.

3. A method for selectively recovering rare earth elements (REE) according to claim 1 or 2, wherein step (b) of aeration leaching is performed by selectively dissolving the REE as a rare earth salt, the magnetic powder below and above the sieve is added to water and acid, and both the REE and the ferrous / ferric salt are leached in the presence of air at a pH in the range of 1 to 7, a leaching temperature in the range of room temperature from 20 to 40°C to 100°C, and a stirring speed of 5 to 2000 rpm for 1 to 12 hours to provide the rare earth salt and the ferrous salt, and the ferrous salt A method comprising: a salt reacting with dissolved oxygen in the air, oxygen enriched in the air, or oxygen or ozone to be converted into a ferric salt, the ferric salt being unstable in the aforementioned pH range and dissociating into iron oxide and / or iron hydroxide to release acid, and this acid further reacting with undissolved magnet powder, and continuing the aeration leaching process until the magnet powder is completely consumed, thereby obtaining a desired mother liquor containing a rare earth salt and a residue containing iron oxide and / or iron hydroxide as byproducts, in a yield of more than 90%.

4. A method for selectively recovering rare earth elements (REEs) according to claims 1 to 3, wherein in step (b), the magnetic powder and the acid are supplied in a ratio of 1:2 to 1:100, and the acid includes organic acids and inorganic acids.

5. A method for selectively recovering rare earth elements (REEs) according to claims 1 to 4, wherein step (c) is a negligible amount of Fe, with the residue containing iron oxide and / or iron hydroxide removed. 2+ A method comprising reacting a filtered mother liquor containing with oxalic acid to precipitate rare earth elements (REE) in the form of rare earth oxalates, and calcining these in air at 800°C to obtain rare earth oxides.

6. A method for selectively recovering rare earth elements (REEs) according to claims 1 to 5, wherein the acid concentration during leaching in step (b) is sufficiently high to initiate iron precipitation and sufficiently low to maintain the rare earths in the solution within a pH range of 1 to 6.

7. A method for selectively recovering rare earth elements (REEs) according to claims 1 to 6, wherein the amount of acid consumed for selective recovery of rare earths from a magnet can be reduced, and a REE yield of 99% and a purity of 99% can be achieved by reference to this method.

8. A method for selectively recovering rare earth elements (REE) according to claims 1 to 7, wherein the used neodymium iron boron (NdFeB) magnets include consumer scrap and residues (magnetic shavings, defective magnets, REE-containing residues from metal manufacturing, electric arc furnace residues, industrial residues, etc.), or used products consisting of small fluorescent lamps, LEDs, LCD backlights, plasma screens, cathode ray tubes, magnets, automobiles (motor magnets, switches, sensors, actuators), mobile phones (speakers, switches), hard disk drives (HDDs), consumer electrical and electronic equipment, electric vehicles and hybrid vehicles, wind turbines, nickel metal halide batteries, and catalysts.

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