Combined reagent for enriching rare earth and method for enriching rare earth from rare earth ore leaching mother liquor
By using a combination reagent of pretreated magnesium oxide slurry and impurity inhibitors, combined with the precipitation treatment of rare earth seeds, the problems of low rare earth grade and impurity residue in rare earth mines are solved, and the efficient enrichment and purity improvement of rare earths are achieved.
Patent Information
- Application Number
- CN202411633378.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-15
- Publication Date
- 2025-02-14
AI Technical Summary
The rare earth grade of existing rare earth mines is low and the content of impurities is high, resulting in high consumption of magnesium oxide during rare earth enrichment, impurities residue, and low purity and recovery rate of rare earths.
Using combined reagents, including pretreatment of magnesium oxide slurry and impurity inhibitors (such as sulfosalicylic acid and/or acetylacetone), the magnesium oxide is evenly dispersed by sonication, ultra-long stirring or high-speed stirring, combined with rare earth seeds Perform precipitation treatment to avoid competing for precipitation with rare earths.
The use of magnesium oxide is reduced, the purity and recovery rate of rare earths are improved, impurity residues are reduced, and efficient enrichment of rare earth products and resource recycling is achieved.
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Figure CN119433251A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of rare earth metal purification, and in particular relates to a combined reagent and a method for enriching rare earth from rare earth leaching mother liquor. Background Art
[0002] In view of the southern ionic rare earth mines rich in medium and heavy rare earth resources, my country has innovatively used magnesium sulfate as a leaching agent and developed a rare earth process of "magnesium sulfate leaching-magnesium oxide enrichment". This process does not generate waste residue throughout the process, effectively avoiding the problem of excessive ammonia and nitrogen in wastewater, promoting the transformation of the rare earth industry to a clean production model, and achieving a dual improvement in economic and environmental benefits. However, due to the differences in the specific composition of rare earth mines and the immaturity of the process, the above process still faces some challenges:
[0003] For example, the rare earth grade of current rare earth mines is low (less than 1g / L), and the content of impurity elements (such as aluminum and iron) is high, which not only leads to a large consumption of magnesium oxide when enriching rare earths, but also the impurity elements are easy to remain. The content of rare earth oxides in the final rare earth enrichment is only 6-9%, and the purity and recovery rate of rare earths are both low. Summary of the invention
[0004] The purpose of the present invention is to provide a combined reagent for rare earth enrichment and a method for enriching rare earth from rare earth leaching mother liquor. The present invention allows impurity elements such as iron and aluminum to remain in the supernatant by adding an impurity inhibitor, thereby avoiding competition between the impurity elements and the low-concentration rare earth elements during the precipitation process, reducing the amount of magnesium oxide used, and improving the purity and recovery rate of rare earth.
[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:
[0006] The present invention provides a combined reagent for rare earth enrichment, comprising a pretreated magnesium oxide slurry and an impurity inhibitor;
[0007] The pretreated magnesium oxide slurry is obtained by subjecting magnesium oxide slurry to ultrasonic treatment, ultra-long stirring treatment or high-speed stirring treatment;
[0008] The impurity inhibitor includes sulfosalicylic acid and / or acetylacetone.
[0009] Preferably, the concentration of magnesium oxide in the magnesium oxide slurry is 0.08-0.15 g / L.
[0010] Preferably, the frequency of the ultrasonic treatment is 20-40kHz, and the time is 1-2h; the rotation speed of the ultra-long stirring treatment is 200-350rpm, and the time is 24-36h; the rotation speed of the high-speed stirring treatment is 2500-3000rpm, and the time is 1.5-3h.
[0011] Preferably, the mass ratio of the impurity inhibitor to the magnesium oxide slurry is 0.01-0.02:1.
[0012] The present invention provides a method for enriching rare earth from rare earth leaching mother liquor, wherein the rare earth elements are calculated as rare earth oxides, and the concentration of the rare earth elements in the rare earth leaching mother liquor does not exceed 1 g / L, comprising the following steps:
[0013] Mixing rare earth leaching mother liquor with rare earth seed crystals to obtain rare earth mixed liquor;
[0014] The rare earth mixed solution is mixed with a combined reagent, and precipitation treatment and solid-liquid separation are performed in sequence to obtain rare earth hydroxide;
[0015] The combined reagent is the combined reagent described in the above technical solution.
[0016] Preferably, the concentration of rare earth elements in the rare earth leaching mother solution is 0.1-0.44 g / L.
[0017] Preferably, the rare earth elements are calculated as rare earth oxides, and the mass fraction of the rare earth elements in the rare earth seeds is 20-40%; the ratio of the mass of the rare earth in the rare earth seeds to the mass of the rare earth in the rare earth leaching mother solution is 0.4-0.8:1.
[0018] Preferably, the mass ratio of the rare earth leaching mother solution to the magnesium oxide in the combined reagent is 0.1-0.4:0.16-0.76.
[0019] Preferably, the precipitation treatment time is 1 to 2 hours.
[0020] Preferably, the precipitation treatment is carried out under stirring conditions, and the stirring speed is 100-200 rpm.
[0021] The present invention provides a combination reagent for rare earth enrichment, including a pretreated magnesium oxide slurry and an impurity inhibitor; the pretreated magnesium oxide slurry is obtained by ultrasonic treatment, ultra-long stirring treatment or high-speed stirring treatment of magnesium oxide slurry; the impurity inhibitor includes sulfosalicylic acid and / or acetylacetone. The present invention subjects the magnesium oxide slurry to ultrasonic treatment, ultra-long stirring treatment or high-speed stirring treatment, so that the magnesium oxide that is originally slightly soluble in water can be evenly dispersed to form a stable slurry, thereby significantly improving its reaction activity. When the combination reagent provided by the present invention is applied to rare earth recovery, the impurity inhibitor can inhibit the reaction of impurity elements such as iron and aluminum with hydroxide, effectively allowing impurity elements such as iron and aluminum to remain in the supernatant, avoiding competition between impurity elements and low-concentration rare earth elements during precipitation, thereby reducing the amount of magnesium oxide used; it can also prevent impurities from mixing into the final rare earth hydroxide, thereby improving the purity of rare earth products.
[0022] The present invention also provides a method for enriching rare earths from rare earth leaching mother liquor, comprising the following steps: mixing the rare earth leaching mother liquor with rare earth seeds to obtain a rare earth mixed liquor; mixing the rare earth mixed liquor with a combination reagent, and sequentially performing precipitation treatment and solid-liquid separation to obtain rare earth hydroxides; the combination reagent is the combination reagent described in the above technical solution; the rare earth elements are calculated as rare earth oxides, and the concentration of the rare earth elements in the rare earth leaching mother liquor does not exceed 1g / L. In the rare earth precipitation link, the present invention introduces rare earth seeds, which not only accelerates the precipitation process and improves the precipitation efficiency; but also consumes the residual magnesium ions in the rare earth product, further reduces the use of magnesium oxide, and realizes efficient utilization of resources.
[0023] Furthermore, the present invention can effectively reduce the magnesium ion content in the final rare earth product obtained during the pulping process by precisely controlling the amount of magnesium oxide, significantly improve the purity of the rare earth product, and obtain a higher quality rare earth enriched product. The method of the present invention is suitable for treating low-concentration rare earth tailings produced by current mines, effectively solving the problem of enriching rare earth leaching mother liquor, and opening up a new path for the efficient utilization of rare earth resources.
[0024] Furthermore, no waste residue is generated during the entire process of the present invention, and the supernatant after precipitation can be recovered and used to prepare other products, such as leaching solution used in rare earth ore mining and leaching, thereby realizing the recycling of resources and reflecting the green and environmentally friendly production concept. The method of the present invention is efficient and environmentally friendly, and the implementation of the method will help significantly improve the rare earth recovery rate, reduce magnesium oxide consumption, reduce product impurities, and improve the quality of rare earth products, thereby enhancing the competitiveness of enterprises in the global market.
[0025] Furthermore, in order to improve the crystallization effect of the obtained rare earth enriched product in the prior art, it is often necessary to add a flocculant (such as polyacrylamide) to help rapid sedimentation and improve sedimentation efficiency. However, this method easily causes a large amount of impurity ions (such as iron and aluminum) to be simultaneously sunk into the obtained rare earth product, affecting product quality, and also causing the flocculant to enter the extraction system, affecting subsequent rare earth separation. The present invention introduces a small amount of rare earth enriched product as a seed in the rare earth precipitation step, thereby significantly increasing the rare earth particles in the obtained rare earth enriched product, directly promoting the increase in sedimentation rate. This improvement avoids the dependence on flocculants in traditional processes, not only simplifies the process flow, but also further reduces production costs, achieving a dual increase in economic benefits and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0027] Figure 1 This is a SEM electron microscope image of magnesium oxide slurry without any pretreatment;
[0028] Figure 2 This is a SEM electron microscope image of magnesium oxide slurry after ultrasonic treatment;
[0029] Figure 3 This is a SEM electron microscope image of magnesium oxide slurry after high-speed stirring;
[0030] Figure 4 This is the SEM electron microscope image of magnesium oxide slurry after ultra-long stirring treatment. DETAILED DESCRIPTION
[0031] The present invention provides a combined reagent for rare earth enrichment, comprising a pretreated magnesium oxide slurry and an impurity inhibitor;
[0032] The pretreated magnesium oxide slurry is obtained by subjecting magnesium oxide slurry to ultrasonic treatment, ultra-long stirring treatment or high-speed stirring treatment;
[0033] The impurity inhibitor includes sulfosalicylic acid and / or acetylacetone.
[0034] In the present invention, unless otherwise specified, the raw materials used are commercially available products well known to those skilled in the art or are prepared by methods well known to those skilled in the art.
[0035] The combined reagent for rare earth enrichment of the present invention includes a pretreated magnesium oxide slurry. In the present invention, the pretreated magnesium oxide slurry is obtained by ultrasonic treatment, ultra-long stirring treatment or high-speed stirring treatment of magnesium oxide slurry. In the present invention, the concentration of magnesium oxide in the magnesium oxide slurry can be 0.08-0.15 g / L; in a specific embodiment, the concentration of magnesium oxide in the magnesium oxide slurry can be 0.08 g / L, 0.1 g / L or 0.15 g / L. In the present invention, the frequency of the ultrasonic treatment can be 20-40 kHz, and the time can be 1-2 h; in a specific embodiment, the frequency of the ultrasonic treatment can be 20 kHz, 30 kHz or 40 kHz, and the time can be 1 h, 1.5 h or 2 h. In the present invention, the rotation speed of the ultra-long stirring treatment can be 200-350rpm, and the time can be 24-36h; in a specific embodiment, the rotation speed of the ultra-long stirring treatment can be 200rpm, 250rpm, 300rpm or 350rpm, and the time can be 24h, 28h, 32h or 36h. In the present invention, the rotation speed of the high-speed stirring treatment can be 2500-3000rpm, and the time can be 1.5-3h; in a specific embodiment, the rotation speed of the high-speed stirring treatment can be 2500rpm, 2700rpm, 2800rpm or 300000rpm, and the time can be 1.5h, 2h, 2.5h or 3h. In the present invention, ultrasonic treatment can generate high-frequency compression and rarefaction waves in the liquid, forming tiny eddies and shear forces, which help to break the weak bonds between magnesium oxide crystals and promote the formation and growth of magnesium oxide crystals; and ultrasonic waves can also increase the contact area between the solution and magnesium oxide, provide more nucleation points, and help to form smaller and more uniform magnesium oxide crystals. In the present invention, the high-speed stirring process can break the agglomeration between the magnesium oxide particles by increasing the shear force and turbulence intensity of the liquid, promote the uniform dispersion of the magnesium oxide particles, and thus improve the overall uniformity of the obtained magnesium oxide slurry. In the present invention, the ultra-long stirring process can promote the full dispersion of particles in the magnesium oxide slurry, improve the uniformity of the magnesium oxide slurry, and promote the complete progress of the chemical reaction, thereby improving the chemical stability of the magnesium oxide slurry.
[0036] The combined reagent for rare earth enrichment of the present invention includes an impurity inhibitor, which includes sulfosalicylic acid and / or acetylacetone; in a specific embodiment, the impurity inhibitor is sulfosalicylic acid or acetylacetone. In the present invention, the mass ratio of the impurity inhibitor to the magnesium oxide slurry can be 0.01 to 0.02:1; in a specific embodiment, the mass ratio of the impurity inhibitor to the magnesium oxide slurry can be 0.01:1, 0.015:1 or 0.02:1.
[0037] In an embodiment of the present invention, the preparation method of the combination reagent may include the following steps: subjecting the magnesium oxide slurry to ultrasonic treatment, ultra-long stirring treatment or high-speed stirring treatment to obtain a pretreated magnesium oxide slurry; mixing the pretreated magnesium oxide slurry with an impurity inhibitor and performing a first stirring to obtain the combination reagent. In the present invention, the first stirring time may be 15 to 30 minutes, specifically 15 minutes, 20 minutes, 25 minutes or 30 minutes. The present invention mixes the pretreated magnesium oxide slurry with the impurity inhibitor and then stirs it, so that the components of the obtained mixed material are evenly distributed, and ensures that the impurity inhibitor is fully combined with the pretreated magnesium oxide slurry.
[0038] The present invention also provides a method for enriching rare earth from rare earth leaching mother liquor, wherein the rare earth elements are calculated as rare earth oxides, and the concentration of the rare earth elements in the rare earth leaching mother liquor does not exceed 1 g / L, comprising the following steps:
[0039] Mixing rare earth leaching mother liquor with rare earth seed crystals to obtain rare earth mixed liquor;
[0040] The rare earth mixed solution is mixed with a combined reagent, and precipitation treatment and solid-liquid separation are performed in sequence to obtain rare earth hydroxide;
[0041] The combined reagent is the combined reagent described in the above technical solution.
[0042] In the present invention, the rare earth elements are calculated as rare earth oxides, and the concentration of the rare earth elements in the rare earth leaching mother solution does not exceed 1g / L, specifically 0.1-0.44g / L; in a specific embodiment, the concentration of the rare earth elements in the rare earth leaching mother solution can be 0.1g / L, 0.24g / L or 0.44g / L. In the present invention, the mass ratio of the rare earth leaching mother solution to the magnesium oxide in the combined reagent can be 0.1-0.4:0.16-0.76; in a specific embodiment, the mass ratio of the rare earth leaching mother solution to the magnesium oxide in the combined reagent can be 0.2-0.3:0.2-0.6. In a specific embodiment of the present invention, the rare earth leaching mother solution comes from an ionic rare earth ore leaching solution.
[0043] In the present invention, the rare earth seed is rare earth oxalate, rare earth carbonate, or rare earth hydroxide precipitated by magnesium oxide; the rare earth element is calculated as rare earth oxide, and the mass fraction of the rare earth element in the rare earth seed is 20-40%; in a specific embodiment, the mass fraction of the rare earth element in the rare earth seed can be 20%, 25% or 26%. In the present invention, the ratio of the mass of the rare earth in the rare earth seed to the mass of the rare earth in the rare earth leaching mother solution can be 0.4-0.8:1; in a specific embodiment, the ratio of the mass of the rare earth in the rare earth seed to the mass of the rare earth in the rare earth leaching mother solution can be 0.4:1, 0.5:1, 0.6:1, 0.7:1 or 0.8:1.
[0044] In an embodiment of the present invention, the rare earth leaching mother liquor and the rare earth seed crystals can be mixed and then stirred for the second time to obtain a rare earth mixed solution; the combined reagent is added dropwise to the rare earth mixed solution, and a precipitation treatment is performed under the condition of the third stirring to obtain a reaction liquid; the reaction liquid is allowed to stand for solid-liquid separation, and the obtained solid material is the rare earth hydroxide. In the present invention, the second stirring time can be 10 to 15 minutes, specifically 10 minutes, 12 minutes or 15 minutes; the rate of dropping the combined reagent can be 5 to 10 mL / min, specifically 5 mL / min, 6 mL / min, 7 mL / min, 8 mL / min, 9 mL / min or 10 mL / min; the speed of the third stirring can be 100 to 200 rpm, specifically 100 rpm, 150 rpm or 200 rpm. In the present invention, the precipitation treatment time can be 1 to 2 hours, specifically 1 hour, 1.5 hours or 2 hours. In the present invention, the solid-liquid separation can be filtration.
[0045] The present invention mixes rare earth leaching mother liquor and rare earth seed crystals and then stirs them, so that the rare earth seed crystals can be evenly dispersed in the rare earth leaching mother liquor, and promotes effective contact between the rare earth seed crystals and components in the rare earth leaching mother liquor.
[0046] The present invention performs precipitation treatment under stirring conditions, which can ensure that the pretreated magnesium oxide slurry fully reacts with the rare earth leaching mother liquor and promotes the precipitation of rare earth elements.
[0047] The present invention allows the reaction liquid that has been precipitated to stand for solid-liquid separation, thereby not only collecting high-purity rare earth enriched products (solid materials), but also the collected liquid materials can be reused in preparing leaching agents, thus realizing the recycling of resources.
[0048] The principle of the method of the present invention is as follows:
[0049] (1) Principles of ultrasonic treatment, ultra-long stirring treatment or high-speed stirring treatment of magnesium oxide slurry:
[0050] Magnesium oxide is a weakly alkaline oxide that reacts with water to form magnesium hydroxide. The rare earth leaching mother liquor reacts with the slurried magnesium oxide. As the pH value of the solution increases, the rare earth ions combine with the magnesium ions and hydroxide ions to form an insoluble rare earth hydroxide precipitate. The reaction formula is shown in Formulas 1 to 2:
[0051] MgO+H2O→Mg(OH)2 Formula 1;
[0052] 3MgO+2RE 3 ++3H2O→2RE(OH)3↓+3Mg 2 +Formula 2;
[0053] Ultrasonic treatment, long stirring or high-speed stirring can more effectively break up and disperse magnesium oxide crystals, exposing more active sites on their surfaces, which helps to increase the activity and reaction rate of magnesium oxide.
[0054] (2) Impurity inhibitor principle: sulfosalicylic acid or acetylacetone is more likely to combine with impurities such as aluminum and iron to form a complex under normal temperature and acidic conditions; and rare earth is more likely to hydrolyze after reacting with sulfosalicylic acid or acetylacetone, which greatly reduces the probability of rare earth forming a complex with sulfosalicylic acid or acetylacetone. The present invention utilizes this principle and uses sulfosalicylic acid or acetylacetone as an impurity inhibitor to purify and enrich the rare earth leaching mother liquor.
[0055] In the present invention, the reaction formulas for sulfosalicylic acid to form a complex with aluminum and iron are shown in Formulas 3 to 4:
[0056] Al 3 ++3C6H4(OH)SO3-→Al[C6H4(OH)SO3]3 Formula 3;
[0057] Fe 3 ++3C6H4(OH)SO3-→Fe[C6H4(OH)SO3]3 Formula 4;
[0058] The reaction formulas for the formation of complexes between acetylacetone and aluminum and iron are shown in Formulas 5 to 6:
[0059] Al 3 ++3C5H8O2→Al(C5H7O2)3+3H+Formula 5;
[0060] Fe 3 ++3C5H8O2→Fe(C5H7O2)3+3H+Formula 6;
[0061] (3) Principle of adding rare earth seeds:
[0062] In the process of enriching rare earth leaching mother liquor, the introduction of already formed rare earth enriched materials as "seeds" (i.e. rare earth seed crystals) can promote the precipitation and precipitation of rare earth elements. Rare earth seed crystals provide an active surface on which rare earth ions gather to form larger crystals. This method can improve the recovery rate and purity of rare earths, while accelerating the precipitation rate and optimizing the entire leaching and enrichment process. By precisely controlling the type, size and addition amount of rare earth seed crystals, the precipitation behavior of rare earth elements can be more effectively regulated to achieve efficient and environmentally friendly rare earth extraction.
[0063] The present invention effectively reduces the amount of magnesium oxide by optimizing the process flow and parameter control, which not only reduces the cost of raw materials, but also reduces the energy consumption and environmental load in the production process, and improves the economy and environmental protection of the entire process. In addition, the method described in the present invention significantly reduces the impurity content in rare earth-enriched products and improves the purity of rare earth elements. This achievement is of great significance for improving the quality of final products and meeting the needs of high-end markets, and also opens up new ways for the high-value utilization of rare earth resources. At the same time, the present invention introduces seed crystal technology into the process, which significantly increases the rare earth particles in rare earth-enriched products, directly promoting the improvement of sedimentation rate. This improvement avoids the dependence on flocculants in traditional processes, not only simplifies the process flow, but also further reduces production costs, achieving a dual improvement in economic benefits and production efficiency.
[0064] In addition, when the rare earth in the rare earth leaching mother liquor is enriched by the existing technology, the content of rare earth oxide in the rare earth enrichment is only 6-9%, the rare earth recovery rate is 80-90%, and the rare earth residue in the supernatant is 20-30 mg / L; while the rare earth in the rare earth leaching mother liquor is enriched by the method provided by the present invention, the REO content in the obtained rare earth hydroxide is more than 45%, the rare earth recovery rate is more than 99%, and the REO content in the supernatant is only 0.12-0.89 mg / L, which is significantly better than the existing technology. It can be seen that the method of the present invention not only improves the purity of rare earth products, but also significantly increases the output, directly promoting the improvement of economic benefits; high-purity and high-yield rare earth products will enhance the market competitiveness of enterprises and inject new vitality into the sustainable development of the rare earth industry.
[0065] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0066] The magnesium oxide slurry used in the embodiment comprises high-purity magnesium oxide and water, wherein the high-purity magnesium oxide is industrial grade and the mass content of magnesium oxide in the high-purity magnesium oxide is 91%;
[0067] The source of the rare earth leaching mother liquor used in the embodiment is the leaching liquor from the southern ionic rare earth mine;
[0068] The source of the rare earth seed crystals used in the examples is the rare earth enriched material prepared by the scheme of the present invention.
[0069] Example 1
[0070] Take 299 mL of magnesium oxide slurry with a concentration of 0.1 g / L, and use an ultrasonic rod with a frequency of 40 kHz to ultrasonically treat the magnesium oxide slurry for 2 hours; after the ultrasonic treatment is completed, a pretreated magnesium oxide slurry is obtained; 3 mL of sulfosalicylic acid is added to the pretreated magnesium oxide slurry and stirred for 15 minutes to obtain a combined reagent (302 mL).
[0071] Take 4L of rare earth leaching mother liquor (REO = 0.44g / L, the mass of magnesium oxide is about 1.7 times the mass of rare earth in the rare earth leaching mother liquor), add rare earth seeds containing 0.88g of rare earth (the proportion of REO in the rare earth seeds is 20wt%) to the rare earth leaching mother liquor, mix and stir for 10min to obtain a mother liquor mixture (4.302L).
[0072] The combined reagent was added to the mother liquor mixture at a rate of 10 mL / min. Stirring and timing were started at the same time as the combined reagent was added. The obtained mixture was stirred at a speed of 100 rpm for 2 hours. After the reaction was completed, the obtained reaction liquid was allowed to stand and then filtered to collect the filtrate and precipitate respectively.
[0073] The filtrate and the precipitate were tested by ICP-OES, and the test results showed that the REO content in the precipitate was 50.11%, the REO content in the filtrate was only 0.12 mg / L, and the rare earth recovery rate was 99.97%. It can be seen that the scheme of Example 1 achieves rare earth enrichment and has a high rare earth recovery rate.
[0074] Figure 1 This is a SEM electron microscope image of magnesium oxide slurry without any pretreatment; Figure 2 This is the SEM electron microscope image of magnesium oxide slurry after ultrasonic treatment.
[0075] Combination Figures 1-2 It can be seen that ultrasonic treatment can more effectively break up and disperse magnesium oxide crystals, exposing more active sites on their surface, which helps to improve the activity and reaction rate of magnesium oxide.
[0076] Comparative Example 1
[0077] Rare earth enrichment was carried out according to the scheme of Example 1, except that the mother liquor was treated with magnesium oxide slurry without any pretreatment (including ultrasonic treatment and stirring treatment), and other conditions were the same as in Example 1.
[0078] The results showed that the REO content in the precipitate was 25.31%, the REO content in the filtrate was 0.15 g / L, and the rare earth recovery rate was 37.50%.
[0079] Comparative Example 2
[0080] Rare earth enrichment was carried out according to the scheme of Example 1, except that sulfosalicylic acid was not added, and other conditions were the same as in Example 1.
[0081] The results showed that the REO content in the precipitate was 45.98%, the REO content in the filtrate was only 0.45 mg / L, and the rare earth recovery rate was 98.13%.
[0082] Comparative Example 3
[0083] Rare earth enrichment was carried out according to the scheme of Example 1, except that no rare earth seed crystals were added, and other conditions were the same as in Example 1.
[0084] The results showed that the REO content in the precipitate was 34.47%, the REO content in the filtrate was only 0.89 mg / L, and the rare earth recovery rate was 96.26%.
[0085] Comparative Example 4
[0086] Rare earth enrichment was carried out according to the scheme of Example 1, except that the frequency of ultrasonic treatment was adjusted to 10 kHz, and other conditions were the same as in Example 1.
[0087] The results showed that the REO content in the precipitate was 28.56%, the REO content in the filtrate was only 0.14 g / L, and the rare earth recovery rate was 41.66%.
[0088] Example 2
[0089] Take 216 mL of magnesium oxide slurry with a concentration of 0.1 g / L, and use an ultrasonic rod with a frequency of 40 kHz to ultrasonically treat the magnesium oxide slurry for 2 hours; after the ultrasonic treatment is completed, a pretreated magnesium oxide slurry is obtained; 2 mL of sulfosalicylic acid is added to the pretreated magnesium oxide slurry and stirred for 20 minutes to obtain a combined reagent (218 mL).
[0090] Take 5L of rare earth leaching mother liquor (REO = 0.24g / L, the mass of magnesium oxide is about 1.8 times the mass of rare earth in the rare earth leaching mother liquor), add rare earth seeds containing 0.72g of rare earth (the proportion of REO in the rare earth seeds is 25wt%) to the rare earth leaching mother liquor, mix and stir for 10min to obtain a mother liquor mixture (5.218L).
[0091] The combined reagent was added to the mother liquor mixture at a rate of 10 mL / min. Stirring and timing were started at the same time as the combined reagent was added. The obtained mixture was stirred at a speed of 100 rpm for 2 hours. After the reaction was completed, the obtained reaction liquid was allowed to stand and then filtered to collect the filtrate and precipitate respectively.
[0092] The test results show that the REO content in the precipitate is 46.15%, the REO content in the filtrate is only 0.89 mg / L, and the rare earth recovery rate is 99.61%. It can be seen that the scheme of Example 2 achieves rare earth enrichment and has a high rare earth recovery rate.
[0093] Example 3
[0094] Take 185 mL of magnesium oxide slurry with a concentration of 0.1 g / L, and use an ultrasonic rod with a frequency of 40 kHz to ultrasonically treat the magnesium oxide slurry for 2 hours; after the ultrasonic treatment is completed, a pretreated magnesium oxide slurry is obtained; 4 mL of acetylacetone is added to the pretreated magnesium oxide slurry and stirred for 15 minutes to obtain a combined reagent (189 mL).
[0095] Take 10L of rare earth leaching mother liquor (REO = 0.1g / L, the mass of magnesium oxide is about 1.85 times the mass of rare earth in the rare earth leaching mother liquor), add rare earth seeds containing 0.8g of rare earth (the proportion of REO in the rare earth seeds is 26wt%) to the rare earth leaching mother liquor, mix and stir for 15min to obtain a mother liquor mixture (10.189L).
[0096] The combined reagent was added to the mother liquor mixture at a rate of 10 mL / min. Stirring and timing were started at the same time as the combined reagent was added. The obtained mixture was stirred at a speed of 100 rpm for 2 hours. After the reaction was completed, the obtained reaction liquid C was allowed to stand and then filtered to collect the filtrate and precipitate respectively.
[0097] The test results show that the REO content in the precipitate is 48.29%, the REO content in the filtrate is only 0.78 mg / L, and the rare earth recovery rate is 99.35%. It can be seen that the scheme of Example 3 achieves rare earth enrichment and has a high rare earth recovery rate.
[0098] Example 4
[0099] Take 285mL of magnesium oxide slurry with a concentration of 0.1g / L, and use a stirrer with a rotation speed of 3000rpm to stir the magnesium oxide slurry for 2h; after the stirring treatment is completed, a strongly stirred magnesium oxide slurry is obtained; 6mL of acetylacetone is added to the strongly stirred magnesium oxide slurry and stirred for 15min to obtain a combined reagent (291mL).
[0100] Take 10L of rare earth leaching mother liquor (REO = 0.15g / L, the mass of magnesium oxide is about 1.90 times the mass of rare earth in the rare earth leaching mother liquor), add rare earth seeds containing 1.2g of rare earth (the proportion of REO in the rare earth seeds is 25wt%) to the rare earth leaching mother liquor, mix and stir for 15min to obtain a mother liquor mixture (10.291L).
[0101] The combined reagent was added to the mother liquor mixture at a rate of 10 mL / min. Stirring and timing were started at the same time as the combined reagent was added. The obtained mixture was stirred at a speed of 100 rpm for 2 hours. After the reaction was completed, the obtained reaction liquid C was allowed to stand and then filtered to collect the filtrate and precipitate respectively.
[0102] The test results show that the REO content in the precipitate is 47.95%, the REO content in the filtrate is only 0.53 mg / L, and the rare earth recovery rate is 97.96%. It can be seen that the scheme of Example 4 achieves rare earth enrichment and has a high rare earth recovery rate.
[0103] Figure 3 This is the SEM electron microscope image of magnesium oxide slurry after high-speed stirring. Figure 3 It can be seen that high-speed stirring can effectively break up and disperse magnesium oxide crystals, exposing more active sites on their surface, which helps to improve the activity and reaction rate of magnesium oxide.
[0104] Example 5
[0105] Take 240mL of magnesium oxide slurry with a concentration of 0.1g / L, and use a stirrer with a rotation speed of 250rpm to stir the magnesium oxide slurry for 24h; after the stirring treatment is completed, an ultra-long stirring magnesium oxide slurry is obtained; 5mL of acetylacetone is added to the ultra-long stirring magnesium oxide slurry and stirred for 15min to obtain a combined reagent (245mL).
[0106] Take 10L of rare earth leaching mother liquor (REO = 0.13g / L, the mass of magnesium oxide is about 1.85 times the mass of rare earth in the rare earth leaching mother liquor), add rare earth seeds containing 1.0g of rare earth (the proportion of REO in the rare earth seeds is 26wt%) to the rare earth leaching mother liquor, mix and stir for 15min to obtain a mother liquor mixture (1.245L).
[0107] The combined reagent was added to the mother liquor mixture at a rate of 10 mL / min. Stirring and timing were started at the same time as the combined reagent was added. The obtained mixture was stirred at a speed of 100 rpm for 2 hours. After the reaction was completed, the obtained reaction liquid C was allowed to stand and then filtered to collect the filtrate and precipitate respectively.
[0108] The test results show that the REO content in the precipitate is 49.61%, the REO content in the filtrate is only 0.63 mg / L, and the rare earth recovery rate is 98.27%. It can be seen that the scheme of Example 5 achieves rare earth enrichment and has a high rare earth recovery rate.
[0109] Figure 4 This is the SEM electron microscope image of the magnesium oxide slurry after ultra-long stirring treatment. Figure 4 It can be seen that the ultra-long stirring treatment can effectively break up and disperse the magnesium oxide crystals, exposing more active sites on their surface, which helps to improve the activity and reaction rate of magnesium oxide.
[0110] In summary, the method of the present invention achieves the reduction of magnesium oxide dosage, the improvement of enrichment purity, the enhancement of sedimentation efficiency and the significant improvement of economic benefits through a series of innovative process optimizations, which provides strong technical support for the efficient and environmentally friendly extraction of rare earth elements and shows broad application prospects.
[0111] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A combined reagent for rare earth enrichment, characterized in that: including pre-treating magnesium oxide slurry and impurity inhibitors; The pretreated magnesium oxide slurry is obtained by subjecting magnesium oxide slurry to ultrasonic treatment, ultra-long stirring treatment or high-speed stirring treatment; The impurity inhibitor includes sulfosalicylic acid and / or acetylacetone.
2. The combined reagent according to claim 1, characterized in that: The concentration of magnesium oxide in the magnesium oxide slurry is 0.08-0.15 g / L.
3. The combined reagent according to claim 1 or 2, characterized in that: The frequency of the ultrasonic treatment is 20-40kHz, and the time is 1-2h; the rotation speed of the ultra-long stirring treatment is 200-350rpm, and the time is 24-36h; the rotation speed of the high-speed stirring treatment is 2500-3000rpm, and the time is 1.5-3h.
4. The combined reagent according to claim 1 or 2, characterized in that: The mass ratio of the impurity inhibitor to the magnesium oxide slurry is 0.01-0.02:
1.
5. A method for enriching rare earths from rare earth leaching mother liquor, wherein the rare earth elements are calculated as rare earth oxides, and the concentration of the rare earth elements in the rare earth leaching mother liquor does not exceed 1 g / L, characterized in that: The following steps are involved: Mixing rare earth leaching mother liquor with rare earth seed crystals to obtain rare earth mixed liquor; The rare earth mixed solution is mixed with a combined reagent, and precipitation treatment and solid-liquid separation are performed in sequence to obtain rare earth hydroxide; The combined reagent is the combined reagent according to any one of claims 1 to 4.
6. The method according to claim 5, characterized in that The concentration of rare earth elements in the rare earth leaching mother solution is 0.1-0.44 g / L.
7. The method according to claim 5, characterized in that The rare earth elements are calculated as rare earth oxides, and the mass fraction of the rare earth elements in the rare earth seeds is 20-40%; the ratio of the mass of the rare earth in the rare earth seeds to the mass of the rare earth in the rare earth leaching mother solution is 0.4-0.8:
1.
8. The method according to claim 5, characterized in that The mass ratio of the rare earth leaching mother solution to the magnesium oxide in the combined reagent is 0.1-0.4:0.16-0.
76.
9. The method according to claim 5, characterized in that The precipitation treatment time is 1 to 2 hours.
10. The method according to claim 5 or 9, characterized in that: The precipitation treatment is carried out under stirring conditions, and the stirring speed is 100-200 rpm.