Method for respectively recovering gallium and lutetium from gallium lutetium garnet waste

Abstract

The invention belongs to the technical field of renewable resource recovery, and particularly relates to a method for respectively recovering gallium and lutetium from gallium lutetium garnet waste. According to the method, gallium and lutetium are separated into water leaching liquid and water leaching residues in a water leaching mode after alkali fusion, then the water leaching liquid is subjected to silicon and aluminum removal, then gallium hydroxide is obtained through precipitation, after the water leaching residues are subjected to acid leaching, acid leaching liquid is subjected to extraction iron removal, extraction purification and reverse extraction, and gallium and lutetium are obtained. And adding excessive oxalic acid to fully precipitate lutetium in the lutetium-rich strip liquor after back extraction, and calcining lutetium oxalate precipitate to obtain lutetium oxide, so that gallium and lutetium are respectively recovered from the gallium lutetium garnet waste, and the technical problem that a method for respectively recovering gallium and lutetium from the gallium lutetium garnet is lacked in the prior art is solved.

Description

Technical Field

[0001] The present application belongs to the field of renewable resource recovery technology, and in particular relates to a method for separately recovering gallium and lutetium from gallium-lutetium garnet waste. Background Art

[0002] Among rare earth elements, lutetium compounds have excellent performance and are widely used. For example, lutetium oxide is a white powder with a high melting point, stability, excellent optical and electrical properties. It is widely used in technical fields such as additives for yttrium aluminum gallium garnet, phosphors, high-performance alloys, catalysts and magnetic materials. Gallium compounds are also important semiconductor materials and are widely used in the manufacture of infrared optical and infrared detection devices, integrated circuits, light-emitting diodes and other optical and electronic devices. However, the content of lutetium and gallium in the earth's crust is not high, and it is necessary to develop methods for the recovery of lutetium and gallium resources.

[0003] Gallium-lutetium garnet waste contains 6-15% lutetium, 5-20% gallium, and 10-20% aluminum. It has a high gallium-lutetium content and a high recovery value. However, gallium-lutetium garnet has a stable silicate structure, and its stable structure needs to be destroyed to recycle gallium-lutetium. At present, the recovery method of lutetium-containing garnet waste is mainly through alkali fusion-hydrochloric acid leaching-evaporation crystallization-alkali precipitation of aluminum silicon-extraction separation-oxalic acid precipitation of lutetium-calcination to obtain high-purity lutetium oxide or through alkali fusion-water leaching-5-10N nitric acid combined with oxidant to leach lutetium-extraction and impurity removal-oxalic acid precipitation of lutetium-calcination to obtain high-purity lutetium oxide. These two methods have high lutetium recovery rate and good impurity separation effect and are widely used in the recovery of lutetium-containing garnet waste. However, there is currently a lack of methods for recovering gallium and lutetium separately from gallium-lutetium garnet. Summary of the invention

[0004] In view of this, the present application provides a method for separately recovering gallium and lutetium from gallium-lutetium garnet waste, which is used to solve the technical problem that there is a lack of methods for separately recovering gallium and lutetium from gallium-lutetium garnet in the prior art.

[0005] The first aspect of the present application provides a method for recovering gallium and lutetium from gallium-lutetium garnet waste, the method comprising the steps of:

[0006] Step S1, sequentially crushing, alkali melting, water immersion, and pure water washing the gallium lutetium garnet waste, and filtering to obtain a water leaching liquid and a water leaching residue;

[0007] Step S2, adding calcium hydroxide to the water leaching solution to perform a silicon-aluminum removal reaction, and filtering to obtain a gallium-rich solution;

[0008] Step S3, adding a pH regulator to the gallium-rich solution to lower the pH for precipitation reaction, and filtering to obtain gallium hydroxide precipitate;

[0009] Step S4, sequentially subjecting the water-leached residue to acid leaching and pure water washing to obtain acid leaching residue and acid leaching liquid;

[0010] Step S5, extracting and removing iron, extracting and purifying, and stripping the acid leaching solution in sequence to obtain a lutetium-rich stripping solution;

[0011] Step S6, adding oxalic acid to the lutetium-rich stripping solution to carry out a precipitation reaction, and filtering to obtain lutetium oxalate;

[0012] Step S7, calcining lutetium oxalate to obtain lutetium oxide.

[0013] Preferably, in step S1, the crushing process is: grinding until the particle size of the gallium lutetium garnet waste is not greater than 200 mesh;

[0014] The alkali melting process is as follows: gallium lutetium garnet waste and caustic soda flakes with a mass ratio of 1:1-3 are placed in a muffle furnace at 600-800° C. and calcined for 2-4 hours.

[0015] Preferably, in step S1, the water leaching process is: leaching the gallium lutetium garnet material after alkali melting and water at a mass ratio of 1:3-5 at a temperature of 70-100° C. for 0.5-2 h, filtering to obtain water leaching residue and a first water leaching liquid;

[0016] The process of pure water washing is: washing the water-leached residue with pure water at least once, filtering to obtain the washed water-leached residue and the second water-leaching liquid.

[0017] Preferably, in step S2, during the silicon-aluminum removal reaction, the molar amount of calcium in the added calcium hydroxide is at least twice the sum of the molar amounts of aluminum and silicon in the gallium-lutetium garnet waste.

[0018] Preferably, in step S2, the temperature of the silicon-aluminum removal reaction is 60-90° C., and the time is 0.5-2 h.

[0019] Preferably, in step S3, the pH value of the precipitation reaction is 6-8, the temperature is room temperature, and the time is 0.5-2h.

[0020] Preferably, in step S4, the acid reagent used for the acid leaching is 3.0-4.0 mol / L hydrochloric acid, the temperature is 70-100° C., and the time is 0.5-2 h.

[0021] Preferably, in step S4, the pure water washing is performed at least once.

[0022] Preferably, in step S5, the extractant used for the extraction and iron removal is selected from an extractant obtained by compounding an amine extractant, an alcohol, and kerosene;

[0023] The extraction and purification agent used in the extraction and purification is selected from the extraction agent P507, the extraction agent C272 and the extraction agent obtained by mixing kerosene;

[0024] The stripping agent used in the stripping is selected from hydrochloric acid.

[0025] Preferably, in step S5, the extractant comprises: 5-15% amine extractant, 10-30% alcohol and 55-85% kerosene;

[0026] The purification extractant comprises: 15-25% P507 extractant, 15-25% C272 extractant and 50-70% kerosene;

[0027] The concentration of the hydrochloric acid is 3-6 mol / L.

[0028] Preferably, in step S5, the extraction is performed at least once, the back-extraction is performed at least once, and the back-extraction is performed at least once.

[0029] Preferably, in step S6, the molar amount of oxalic acid used is at least 1.5 times the molar amount of lutetium in the gallium-lutetium garnet waste.

[0030] Preferably, in step S6, the precipitation reaction is carried out at a temperature of 30-50° C. and for a time of 2-4 hours.

[0031] Preferably, in step S7, the calcination temperature of the oxalic acid is 800-900° C., and the time is 2-4 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A schematic flow chart of a method for recovering gallium and lutetium from gallium-lutetium garnet waste provided in the present application. DETAILED DESCRIPTION

[0034] The present application provides a method for separately recovering gallium and lutetium from gallium-lutetium garnet waste, which is used to solve the technical problem that there is a lack of methods for separately recovering gallium and lutetium from gallium-lutetium garnet in the prior art.

[0035] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0036] In view of the defect that current research mainly focuses on the recovery of lutetium in lutetium-containing garnet waste, and lacks research on the recovery of gallium and lutetium in gallium-lutetium garnet waste, the present application provides a method for separately recovering gallium-lutetium from gallium-lutetium garnet waste, the method comprising: firstly, sequentially crushing, alkali melting, water leaching, pure water washing and filtering the gallium-lutetium garnet waste to obtain a water leaching solution and a water leaching residue; then, calcium hydroxide is added to the water leaching solution to carry out a silicon-aluminum removal reaction and filter to obtain a gallium-rich solution; then, a pH regulator is added to the gallium-rich solution to lower the pH to carry out a precipitation reaction and filter to obtain a gallium hydroxide precipitate; then, the water leaching residue is sequentially acid-leached, washed with pure water and filtered to obtain an acid leaching residue and an acid leaching solution; next, the acid leaching solution is sequentially subjected to extraction and iron removal, extraction purification and stripping to obtain a lutetium-rich stripping solution; then, oxalic acid is added to the lutetium-rich stripping solution to obtain the lutetium oxalate obtained by the reaction, and calcined to obtain lutetium oxide.

[0037] In the method for recovering gallium and lutetium from gallium-lutetium garnet waste provided by the present application, water leaching is used after alkali fusion to obtain water leaching residue and water leaching liquid. During the water leaching process, gallium is easily leached, while lutetium is difficult to leach, thereby realizing the separation of gallium and lutetium, and avoiding the defect that the conventional hydrochloric acid leaching easily causes gallium and lutetium to be leached at the same time, resulting in the difficulty in separating gallium and lutetium. After the water leaching, pure water is also used to wash the water leaching residue, and the gallium remaining on the water leaching residue can be washed into the water leaching liquid; subsequently, calcium hydroxide is used to treat the water leaching liquid, and the water leaching liquid after alkali fusion is a strong pH solution with a pH of 12-14, in which aluminum mainly exists in the form of sodium metaaluminate, silicon mainly exists in the form of sodium silicate, and gallium mainly exists in the form of Ga(OH) 4- The aqueous solution exists in the form of calcium hydroxide, and after calcium hydroxide is added to the aqueous solution, the calcium hydroxide reacts with sodium aluminate to generate aluminum hydroxide precipitate and calcium aluminate, and the sodium silicate reacts with calcium hydroxide to generate calcium silicate precipitate, while gallium is difficult to participate in the reaction under strong alkaline conditions, thereby achieving the purpose of removing silicon and aluminum impurities and obtaining a gallium-rich solution, and then a pH regulator is added to the gallium-rich solution to lower the pH to obtain a gallium hydroxide precipitate, and then the aqueous solution is subjected to acid leaching to allow lutetium to be leached from the aqueous solution to obtain an acid leaching residue and an acid leaching solution, and the acid leaching solution is subjected to impurity removal, purification, and stripping operations, and then oxalic acid is added to react to obtain a lutetium oxalate precipitate; and then calcination is performed to obtain lutetium oxide, so that the method provided by the present application successfully recovers gallium and lutetium from gallium-lutetium garnet waste, respectively, realizes the resource utilization of gallium and lutetium, and overcomes the defect of lack of research on the recovery of gallium and lutetium.

[0038] As a preferred technical solution, in order to effectively destroy the silicate structure of gallium lutetium garnet and improve the effect of alkali fusion, the present application performs crushing pretreatment on gallium lutetium garnet waste, crushing it to 200 mesh (approximately equal to 74um), so that the gallium lutetium garnet waste can fully contact and react with flake caustic soda (sodium hydroxide) during the alkali fusion process; and the amount of raw materials, temperature and time in the alkali fusion process are controlled, and the mass ratio of gallium lutetium garnet waste and flake caustic soda is controlled to be 1:3~5, the alkali fusion temperature is 600~800℃, and the time is 2~4h.

[0039] As a preferred technical solution, in order to effectively promote the separation of gallium-lutetium during the water leaching process and improve the recovery effect of gallium-lutetium, the present application controls the amount of water leaching solution, the temperature and time of water leaching, the mass ratio of gallium-lutetium garnet material and water after alkali fusion is 1:3~5, the water leaching temperature is 70~100℃, and the time is 0.5~2h; at the same time, pure water is used to wash the water leaching residue at least once, reducing the gallium residue in the water leaching residue.

[0040] As a preferred technical solution, in order to remove aluminum and silicon in gallium-lutetium garnet waste as cleanly as possible and improve the gallium recovery effect, the present application controls the amount of calcium hydroxide added and the reaction temperature and time during the silicon-aluminum removal reaction, and controls the molar amount of calcium to be at least twice the sum of the molar amounts of aluminum and silicon in the gallium-lutetium garnet waste, the reaction temperature is 60~90°C, and the time is 0.5~2h.

[0041] As a preferred technical solution, in order to increase the recovery of gallium in gallium-lutetium garnet waste, the present application controls the pH value of the precipitation reaction by adding an acid regulator, and the pH value should be near neutral, pH 6-8.

[0042] As a preferred technical solution, in order to completely remove impurities such as iron in gallium-lutetium garnet waste and improve the effect of lutetium recovery, the present application controls the solvents used in the extraction, purification and stripping processes, and controls the extractant used for extraction and iron removal to be selected from amine extractants, alcohols and kerosene composite extractants, the purification extractant is selected from P507 extractant, C272 extractant and kerosene composite purification extractant, and the stripping agent used for stripping is selected from hydrochloric acid.

[0043] As a preferred technical solution, in order to increase the recovery of lutetium in gallium-lutetium garnet waste, the present application controls the amount of oxalic acid added, and controls the molar amount of oxalic acid to be at least 1.5 times the molar amount of lutetium in the gallium-lutetium garnet waste.

[0044] The following will specifically describe the method for recovering gallium and lutetium from gallium and lutetium garnet waste provided by the present application in combination with the examples and the recovery data of gallium and lutetium.

[0045] Example 1

[0046] Example 1 of the present application provides a method for recovering gallium and lutetium from gallium-lutetium garnet waste, the method comprising: a step of alkali melting and water leaching, a step of removing silicon and aluminum from the water leaching solution, a step of generating a gallium hydroxide precipitate, a step of acid leaching, a step of removing impurities, purifying and stripping the acid leaching solution, a step of generating lutetium oxalate and a step of calcination.

[0047] The steps of alkali melting and water leaching include: first weighing 120g of gallium lutetium garnet waste, grinding it with a mortar and passing it through a 200-mesh screen for later use; then taking 100g of gallium lutetium garnet fine powder and 200g of flake caustic soda, mixing them evenly, putting them into a nickel crucible and placing them in a muffle furnace for calcination at 600°C for 3h; then soaking 300g of the material after natural cooling and 1200mL of pure water at a liquid-to-solid ratio of 4:1 at 85°C for 1h, filtering to obtain water leaching residue and a first water leaching liquid, washing the water leaching residue with 500mL of pure water, filtering to obtain water leaching residue and a second water leaching liquid, and the first The water immersion liquid and the second water immersion liquid are mixed as the water immersion liquid; the gallium-lutetium garnet waste used in this embodiment is analyzed by ICP spectrometer, which includes: 14.63% gallium, 6.70% lutetium, 0.53% iron, 15.61% aluminum and 0.5% silicon, and the water immersion liquid includes: 13.65g gallium (93.34%), 0.001g lutetium (<0.02%), 0.0001g iron (<0.02%), 13.31g aluminum (85.31%) and 0.04g silicon (8.26%).

[0048] The step of removing silicon and aluminum from the water infusion comprises: adding 103.5 g of solid calcium hydroxide to the mixed water infusion of the first water infusion and the second water infusion, reacting at 75° C. for 1 hour to fully remove aluminum and silicon, and filtering to obtain calcium aluminum silicon slag and a gallium-rich solution.

[0049] The step of generating gallium hydroxide precipitate comprises: adding concentrated sulfuric acid to the gallium-rich solution to adjust the pH to 7.5, reacting for 1 hour, filtering and washing to obtain gallium hydroxide.

[0050] The acid leaching step includes: acid leaching hydrochloric acid (concentration 3.5 mol / L) and water leaching residue at a liquid-to-solid ratio of 4:1 at 85°C for 1 hour, filtering and washing to obtain acid leaching residue and acid leaching liquid. ICP spectrometer analysis shows that the acid leaching liquid includes: 0.033g gallium (0.23%), 6.43g lutetium (95.97%), 0.40g iron (75.31%), 0.026g aluminum (0.17%) and 0.0001g silicon (0.03%).

[0051] The steps of impurity removal, purification and stripping of the acid leaching solution include: firstly, mixing the extractant and the acid leaching solution at an O / A ratio of 1: 5 for 10 min to obtain an iron extraction residual solution and a loaded organic phase, wherein the iron content in the iron extraction residual solution is less than 1 mg / L; then, mixing the purification extractant and the iron extraction residual solution at an O / A ratio of 15: 1 for 10 min to obtain a lutetium extraction residual solution and a lutetium-rich organic phase, wherein the lutetium content in the lutetium extraction residual solution is less than 10 mg / L; then, mixing the stripping agent and the lutetium-rich organic phase at an O / A ratio of 11: 1 for 10 min to obtain a lutetium extraction residual solution and a lutetium-rich organic phase, wherein the lutetium content in the lutetium extraction residual solution is less than 10 mg / L; min to obtain a lutetium strip solution and an organic phase, wherein the lutetium content in the organic phase is less than 0.2 mg / L; wherein, the extractant used is obtained by compounding 10% amine extractant N235, 20% octanol and 70% kerosene, and the purification extractant used is obtained by compounding 20% ​​P507 extractant, 20% C272 extractant and 60% kerosene, and the stripping agent is hydrochloric acid (4.5 mol / L).

[0052] The steps of generating lutetium oxalate include: adding excess oxalic acid (concentration of 77 g / L) to the lutetium stripping solution, reacting at 40° C. for 3 hours to generate lutetium oxalate precipitate, filtering and washing to obtain lutetium oxalate, and the amount of oxalic acid used is calculated based on the molar amount of lutetium in the oxalic acid / gallium lutetium garnet waste of 1.7 / 1.

[0053] The calcination step includes: placing lutetium oxalate into a ceramic crucible and calcining at 850° C. for 3 hours to obtain lutetium oxide.

[0054] Example 2

[0055] Example 2 of the present application provides a method for recovering gallium lutetium from gallium lutetium garnet waste, the method comprising: alkali melting and water leaching, a step of removing silicon and aluminum from the water leaching solution, a step of generating gallium hydroxide precipitate, an acid leaching step, a step of removing impurities, purifying and stripping the acid leaching solution, a step of generating lutetium oxalate and a step of calcination. The difference from Example 1 is that the gallium lutetium garnet waste is replaced.

[0056] The steps of alkali melting and water leaching include: first weighing 120g of gallium lutetium garnet waste, grinding it with a mortar and passing it through a 200-mesh screen for later use; then taking 100g of gallium lutetium garnet fine powder and 200g of flake caustic soda, mixing them evenly, putting them into a nickel crucible and placing them in a muffle furnace for calcination at 600°C for 3h; then soaking 300g of the material after natural cooling and 1200mL of pure water at a liquid-to-solid ratio of 4:1 at 85°C for 1h, filtering to obtain water leaching residue and a first water leaching liquid, washing the water leaching residue with 500mL of pure water, filtering to obtain water leaching residue and a second water leaching liquid, and the first The water immersion liquid and the second water immersion liquid are mixed as the water immersion liquid; the gallium-lutetium garnet waste used in this embodiment is analyzed by ICP spectrometer, which includes: 10.65% gallium, 7.68% lutetium, 1.37% iron, 21.11% aluminum and 0.2% silicon, and the water immersion liquid includes: 10.05g gallium (94.38%), 0.001g lutetium (<0.02%), 0.0002g iron (<0.02%), 18.73g aluminum (88.73%) and 0.01g silicon (5.17%).

[0057] The step of removing silicon and aluminum from the water infusion comprises: adding 136.9 g of solid calcium hydroxide to the mixed water infusion of the first water infusion and the second water infusion, reacting at 75° C. for 1 hour to fully remove aluminum and silicon, and filtering to obtain calcium aluminum silicon slag and a gallium-rich solution.

[0058] The step of generating gallium hydroxide precipitate comprises: adding concentrated sulfuric acid to the gallium-rich solution to adjust the pH to 7.5, reacting for 1 hour, filtering and washing to obtain gallium hydroxide.

[0059] The acid leaching step includes: acid leaching hydrochloric acid (concentration 3.5 mol / L) and water leaching residue at a liquid-to-solid ratio of 4:1 at 85°C for 1 hour, filtering and washing to obtain acid leaching residue and acid leaching liquid. ICP spectrometer analysis shows that the acid leaching liquid includes: 0.015g gallium (0.14%), 7.32g lutetium (95.28%), 1.06g iron (77.29%), 0.025g aluminum (0.12%) and 0.00004g silicon (0.02%).

[0060] The steps of impurity removal, purification and stripping of the acid leaching solution include: firstly, mixing the extractant and the acid leaching solution at an O / A ratio of 1: 5 for 10 min to obtain an iron extraction residual solution and a loaded organic phase, wherein the iron content in the iron extraction residual solution is less than 1 mg / L; then, mixing the purification extractant and the iron extraction residual solution at an O / A ratio of 15: 1 for 10 min to obtain a lutetium extraction residual solution and a lutetium-rich organic phase, wherein the lutetium content in the lutetium extraction residual solution is less than 10 mg / L; then, mixing the stripping agent and the lutetium-rich organic phase at an O / A ratio of 11: 1 for 10 min to obtain a lutetium extraction residual solution and a lutetium-rich organic phase, wherein the lutetium content in the lutetium extraction residual solution is less than 10 mg / L; min to obtain a lutetium strip solution and an organic phase, wherein the lutetium content in the organic phase is less than 0.2 mg / L; wherein the extractant used is obtained by compounding 10% amine extractant N235, 20% octanol and 70% kerosene, and the purification extractant used is obtained by compounding 20% ​​P507 extractant, 20% C272 extractant and 60% kerosene, and the stripping agent is hydrochloric acid (4.5 mol / L).

[0061] The steps of generating lutetium oxalate include: adding excess oxalic acid (concentration of 77 g / L) to the lutetium stripping solution, reacting at 40° C. for 3 hours to generate lutetium oxalate precipitate, filtering and washing to obtain lutetium oxalate, and the amount of oxalic acid used is calculated based on the molar amount of lutetium in the oxalic acid / gallium lutetium garnet waste of 1.7 / 1.

[0062] The calcination step includes: placing lutetium oxalate into a ceramic crucible and calcining at 850° C. for 3 hours to obtain lutetium oxide.

[0063] Example 3

[0064] Example 3 of the present application provides a method for recovering gallium lutetium from gallium lutetium garnet waste, the method comprising: alkali melting and water leaching, a step of removing silicon and aluminum from the water leaching solution, a step of generating gallium hydroxide precipitate, an acid leaching step, a step of removing impurities, purifying and stripping the acid leaching solution, a step of generating lutetium oxalate and a step of calcination. The difference from Example 1 is that the amount of calcium hydroxide added is increased.

[0065] The steps of alkali melting and water leaching include: first weighing 120g of gallium lutetium garnet waste, grinding it with a mortar and passing it through a 200-mesh sieve for later use; then taking 100g of gallium lutetium garnet fine powder and 200g of flake caustic soda, mixing them evenly, putting them into a nickel crucible and placing them in a muffle furnace for calcination at 800°C for 3h; then soaking 300g of the material after natural cooling and 1200mL of pure water at a liquid-to-solid ratio of 4:1 at 85°C for 1h, filtering to obtain water leaching residue and a first water leaching liquid, washing the water leaching residue with 500mL of pure water, filtering to obtain water leaching residue and a second water leaching liquid, and the first The water immersion liquid and the second water immersion liquid are mixed as the water immersion liquid; the gallium-lutetium garnet waste used in this embodiment is analyzed by ICP spectrometer, which includes: 14.63% gallium, 6.70% lutetium, 0.53% iron, 15.61% aluminum and 0.5% silicon, and the water immersion liquid includes: 14.37g gallium (98.24%), 0.001g lutetium (<0.02%), 0.0001g iron (<0.02%), 14.13g aluminum (90.55%) and 0.031g silicon (6.24%).

[0066] The step of removing silicon and aluminum from the water infusion comprises: adding 118g of solid calcium hydroxide to the mixed water infusion of the first water infusion and the second water infusion, reacting at 75°C for 1h to fully remove aluminum and silicon, and filtering to obtain calcium aluminum silicon slag and gallium-rich solution.

[0067] The step of generating gallium hydroxide precipitate comprises: adding concentrated sulfuric acid to the gallium-rich solution to adjust the pH to 7.5, reacting for 1 hour, filtering and washing to obtain gallium hydroxide.

[0068] The acid leaching step includes: acid leaching hydrochloric acid (concentration 3.5 mol / L) and water leaching residue at a liquid-to-solid ratio of 4:1 at 85°C for 1 hour, filtering and washing to obtain acid leaching residue and acid leaching solution. ICP spectrometer analysis shows that the acid leaching solution includes: 0.0073g gallium (0.05%), 6.65g lutetium (99.31%), 0.44g iron (82.65%), 0.0047g aluminum (0.03%) and 0.0001g silicon (0.02%).

[0069] The steps of impurity removal, purification and stripping of the acid leaching solution include: firstly, mixing the extractant and the acid leaching solution at an O / A ratio of 1: 5 for 10 min to obtain an iron extraction residual solution and a loaded organic phase, wherein the iron content in the iron extraction residual solution is less than 1 mg / L; then, mixing the purification extractant and the iron extraction residual solution at an O / A ratio of 15: 1 for 10 min to obtain a lutetium extraction residual solution and a lutetium-rich organic phase, wherein the lutetium content in the lutetium extraction residual solution is less than 10 mg / L; then, mixing the stripping agent and the lutetium-rich organic phase at an O / A ratio of 11: 1 for 10 min to obtain a lutetium extraction residual solution and a lutetium-rich organic phase, wherein the lutetium content in the lutetium extraction residual solution is less than 10 mg / L; min to obtain a lutetium strip solution and an organic phase, wherein the lutetium content in the organic phase is less than 0.2 mg / L; wherein, the extractant used is obtained by compounding 10% amine extractant N235, 20% octanol and 70% kerosene, and the purification extractant used is obtained by compounding 20% ​​P507 extractant, 20% C272 extractant and 60% kerosene, and the stripping agent is hydrochloric acid (4.5 mol / L).

[0070] The steps of generating lutetium oxalate include: adding excess oxalic acid (concentration of 77 g / L) to the lutetium stripping solution, reacting at 40° C. for 3 hours to generate lutetium oxalate precipitate, filtering and washing to obtain lutetium oxalate, and the amount of oxalic acid used is calculated based on the molar amount of lutetium in the oxalic acid / gallium lutetium garnet waste of 1.7 / 1.

[0071] The calcination step includes: placing lutetium oxalate into a ceramic crucible and calcining at 850° C. for 3 hours to obtain lutetium oxide.

[0072] Example 4

[0073] This Experimental Example 4 provides data on gallium-lutetium recovered from gallium-lutetium garnet waste provided in Example 1-3, and the data are shown in Table 1-2.

[0074] Table 1: Lutetium oxide recovery data

[0075]

[0076] Table 2: Gallium hydroxide recovery data

[0077]

[0078] As can be seen from Table 1-2, the method provided by the present application successfully recovers gallium and lutetium from gallium-lutetium garnet waste. This is because the present application successfully separates most of the gallium into the water leaching solution by water leaching after alkali melting. The water leaching solution contains 93.34~98.24% of gallium, while most of the lutetium is in the acid leaching solution. The acid leaching solution contains 95.28~99.31% of lutetium, thereby separating the gallium and lutetium in the gallium-lutetium garnet waste.

[0079] It can be further seen from Table 1 that the method provided by the present application not only successfully recovers lutetium from gallium-lutetium garnet waste, but also the purity and yield of the recovered lutetium are good. This is because in the process of recovering lutetium, the present application uses an extractant obtained by compounding an amine extractant, an alcohol and kerosene to extract the lutetium-containing acid leaching solution, so that the iron content in the iron extraction residual solution after extraction is less than 1 mg / L; and uses a purification extractant obtained by compounding a P507 extractant, a C272 extractant and kerosene to extract and purify the iron extraction residual solution, so that the lutetium content in the lutetium extraction residual solution is less than 10 mg / L, and lutetium is enriched in the lutetium-rich organic phase; hydrochloric acid is also used to reversely extract the lutetium-rich organic phase, so that the organic phase, the lutetium content in the organic phase is less than 0.2 mg / L, and lutetium is enriched in the lutetium stripping solution, and then an excess of oxalic acid is added to the lutetium stripping solution, so that the purity and yield of lutetium are good.

[0080] It can be further seen from Table 2 that the method provided by the present application not only successfully recovers gallium from gallium-lutetium garnet waste, but also has good purity and yield of the recovered gallium. This is because in the process of recovering gallium, the present application adds calcium hydroxide to the water leaching solution after alkali fusion, so that aluminum and silicon are precipitated by aluminum hydroxide precipitation, calcium aluminate and calcium silicate, thereby making the recovery rate and recovery effect of gallium in the water leaching solution better.

[0081] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for recovering gallium and lutetium from gallium-lutetium garnet waste, characterized in that: Includes steps: Step S1, sequentially crushing, alkali melting, water immersion, and pure water washing the gallium lutetium garnet waste, and filtering to obtain a water leaching liquid and a water leaching residue; Step S2, adding calcium hydroxide to the water leaching solution to perform a silicon-aluminum removal reaction, and filtering to obtain a gallium-rich solution; Step S3, adding a pH regulator to the gallium-rich solution to lower the pH for precipitation reaction, and filtering to obtain gallium hydroxide precipitate; Step S4, sequentially subjecting the water-leached residue to acid leaching and pure water washing, and filtering to obtain the acid leaching residue and the acid leaching liquid; Step S5, extracting and removing iron, extracting and purifying, and stripping the acid leaching solution in sequence to obtain a lutetium-rich stripping solution; Step S6, adding oxalic acid to the lutetium-rich stripping solution to carry out a precipitation reaction, and filtering to obtain lutetium oxalate; Step S7, calcining lutetium oxalate to obtain lutetium oxide.

2. The method for recovering gallium and lutetium from gallium and lutetium garnet waste according to claim 1, characterized in that: In step S1, the crushing process is: grinding until the particle size of the gallium lutetium garnet waste is not greater than 200 mesh; The alkali melting process is as follows: gallium lutetium garnet waste and caustic soda flakes with a mass ratio of 1:1-3 are placed in a muffle furnace at 600-800° C. and calcined for 2-4 hours.

3. The method for recovering gallium and lutetium from gallium and lutetium garnet waste according to claim 1, characterized in that: In step S1, the water leaching process is: leaching the gallium lutetium garnet material after alkali melting and water at a mass ratio of 1:3-5 at a temperature of 70-100° C. for 0.5-2 hours, filtering to obtain water leaching residue and a first water leaching liquid; The process of pure water washing is: washing the water-leached residue with pure water at least once, filtering to obtain the washed water-leached residue and the second water-leaching liquid.

4. The method for recovering gallium and lutetium from gallium and lutetium garnet waste according to claim 1, characterized in that: In step S2, during the silicon-aluminum removal reaction, the molar amount of calcium in the added calcium hydroxide is at least twice the sum of the molar amounts of aluminum and silicon in the gallium-lutetium garnet waste.

5. The method for recovering gallium and lutetium from gallium and lutetium garnet waste according to claim 1, characterized in that: In step S2, the temperature of the silicon-aluminum removal reaction is 60-90° C., and the time is 0.5-2 h.

6. The method for recovering gallium and lutetium from gallium and lutetium garnet waste according to claim 1, characterized in that: In step S3, the pH value of the precipitation reaction is 6-8, the temperature is room temperature, and the time is 0.5-2h.

7. The method for recovering gallium and lutetium from gallium and lutetium garnet waste according to claim 1, characterized in that: In step S4, the acid reagent used for the acid leaching is 3.0-4.0 mol / L hydrochloric acid, the temperature is 70-100° C., and the time is 0.5-2 h.

8. The method for recovering gallium and lutetium from gallium and lutetium garnet waste according to claim 1, characterized in that: In step S5, the extractant used for the extraction and iron removal is selected from an extractant obtained by compounding an amine extractant, an alcohol, and kerosene; The extraction and purification agent used in the extraction and purification is selected from the extraction agent P507, the extraction agent C272 and the extraction agent obtained by mixing kerosene; The stripping agent used in the stripping is selected from hydrochloric acid.

9. The method for recovering gallium and lutetium from gallium and lutetium garnet waste according to claim 1, characterized in that: In step S6, the molar amount of oxalic acid used is at least 1.5 times the molar amount of lutetium in the gallium-lutetium garnet waste.

10. The method for recovering gallium and lutetium from gallium and lutetium garnet waste according to claim 1, characterized in that: In step S6, the precipitation reaction temperature is 30-50° C. and the time is 2-4 hours.

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