阅读说明：本技术 一种从稀土矿中提取稀土氧化物的方法 (Method for extracting rare earth oxide from rare earth ore ) 是由 易启辉 张勇 赵庆方 张修普 于 2021-08-03 设计创作，主要内容包括：本发明公开了一种从稀土矿中提取稀土氧化物的方法,包括：将稀土矿与水混匀,加氯化铵、硫酸镁和双氧水浸取得到浸出液A和浸出渣A；将浸出渣A装入浸出柱中依次用含硫酸镁、壳寡糖、聚乙二醇的浸取剂A和含硫酸钾、甘氨酸、吡啶-3-羧酸的浸取剂B浸取得浸出液B和浸出渣B；将浸出渣B与水混合,搅拌,静置,固液分离后与浸出液A、浸出液B合并得浸出液；用包括小球藻、螯合树脂和螺旋藻的吸附剂对浸出液进行吸附,将沉淀解吸后得稀土富液,磁处理后加入氧化钙沉淀,固液分离获得稀土沉淀；将含EDTA与柠檬酸的混合溶液、稀土沉淀混合,搅拌,固液分离后将得到的沉淀物与纤维素、水混匀得到浆料；将浆料造球后焙烧。(The invention discloses a method for extracting rare earth oxide from rare earth ore, which comprises the following steps: uniformly mixing rare earth ore and water, adding ammonium chloride, magnesium sulfate and hydrogen peroxide to extract to obtain a leaching solution A and leaching residues A; putting the leaching residue A into a leaching column, and sequentially leaching with a leaching agent A containing magnesium sulfate, chitosan oligosaccharide and polyethylene glycol and a leaching agent B containing potassium sulfate, glycine and pyridine-3-carboxylic acid to obtain a leaching solution B and a leaching residue B; mixing leaching residue B with water, stirring, standing, performing solid-liquid separation, and mixing with leaching solution A and leaching solution B to obtain leaching solution; adsorbing the leachate with adsorbent comprising Chlorella, chelating resin and Spirulina, desorbing the precipitate to obtain rare earth rich solution, magnetically treating, adding calcium oxide for precipitation, and performing solid-liquid separation to obtain rare earth precipitate; mixing a mixed solution containing EDTA and citric acid and the rare earth precipitate, stirring, carrying out solid-liquid separation, and uniformly mixing the obtained precipitate with cellulose and water to obtain a slurry; and pelletizing and roasting the slurry.)

1. A method for extracting rare earth oxide from rare earth ore is characterized by comprising the following steps:

s1, mixing the rare earth ore and water according to the proportion of 1: 3-5, adding ammonium chloride, magnesium sulfate and hydrogen peroxide, stirring for 5-7h, standing for 8-13h, and performing solid-liquid separation to obtain a leaching solution A and a leaching residue A;

s2, filling the leaching residue A into a leaching column, leaching by using a leaching agent A, and leaching by using a leaching agent B to obtain a leaching solution B and a leaching residue B; wherein the leaching agent A is a solution containing magnesium sulfate, chitosan oligosaccharide and polyethylene glycol, the concentration of the magnesium sulfate is 0.07-0.1mol/L, the mass fraction of the chitosan oligosaccharide is 0.5-1.8%, and the mass fraction of the polyethylene glycol is 0.1-1.5%; the leaching agent B is a solution containing potassium sulfate, glycine and pyridine-3-carboxylic acid, wherein the concentration of the potassium sulfate is 0.15-0.22mol/L, the concentration of the glycine is 0.02-0.05mol/L, and the concentration of the pyridine-3-carboxylic acid is 0.01-0.05 mol/L;

s3, mixing the leaching residue B with water according to the ratio of 1: 1-3, stirring for 30-150min, standing for 10-15h, and mixing with the leachate A and the leachate B after solid-liquid separation to obtain leachate;

s4, mixing the adsorbent with the leachate obtained in the step S3, oscillating and adsorbing for 1-2.5 hours, and desorbing the precipitate to obtain a rare earth pregnant solution; wherein, the raw materials of the adsorbent comprise chlorella, chelating resin and spirulina;

s5, carrying out magnetic treatment on the rare earth rich solution, then adding calcium oxide for precipitation, and carrying out solid-liquid separation to obtain a rare earth precipitate;

s6, mixing the mixed solution containing EDTA and citric acid and the rare earth precipitate, stirring for 10-15min at 30-40 ℃, and after solid-liquid separation, uniformly mixing the obtained precipitate with cellulose and water to obtain slurry with the water content of 38-47 wt%; and (3) after pelletizing the slurry, preserving the temperature for 90-150min at 800-880 ℃ to obtain the rare earth oxide.

2. The method of extracting rare earth oxides from rare earth ores as claimed in claim 1, wherein in S1, the amount of ammonium chloride is 0.5 to 0.9 times the weight of the rare earth oxides contained in the rare earth ores; the dosage of the magnesium sulfate is 2-3 times of the weight of the rare earth oxide contained in the rare earth ore, and the dosage of the hydrogen peroxide is 0.15-0.35 time of the weight of the rare earth oxide contained in the rare earth ore.

3. The method of claim 1, wherein in S2, the solid-to-liquid ratio of leaching residue a to leaching agent a is 1 kg: 0.2-0.5L; leaching by using a leaching agent B until the concentration of the rare earth in the leaching solution is lower than 0.1 g/L.

4. The method of extracting rare earth oxides from rare earth ores as claimed in claim 1, wherein in S2, the flow rates of leaching agent a and leaching agent B are each 0.4-0.65ml/min during leaching.

5. The method for extracting rare earth oxides from rare earth ores according to claim 1, wherein in S2, the polyethylene glycol is polyethylene glycol 200, polyethylene glycol 1500, polyethylene glycol 2000 in a weight ratio of 2-10: 1-4: 3-9.

6. The method of claim 1, wherein in S4, the solid-to-liquid ratio of the adsorbent to the leachate is 5-15 g: 1L; the weight ratio of the chlorella to the chelating resin to the spirulina is (1-4): 8-20: 2-7.

7. The method for extracting rare earth oxide from rare earth ore according to claim 1, wherein in S4, in the desorption process, the desorbent is one or more of malic acid, citric acid and hydrochloric acid; the desorption temperature is 40-50 ℃ and the desorption time is 2-5 h.

8. The method for extracting rare earth oxide from rare earth ore as claimed in claim 1, wherein in S5, the magnetic treatment time is 7-18min, and the magnetic field strength is 600-650 kA/m.

9. The method according to claim 1, wherein in S6, the concentration of EDTA is 0.03-0.07mol/L and the concentration of citric acid is 0.01-0.05 mol/L; the liquid-solid ratio of the mixed solution containing EDTA and citric acid to the rare earth precipitate is 0.2-1L: 1 kg.

10. The process for extracting rare earth oxides from rare earth ores according to any one of claims 1 to 9, wherein in S6, the weight ratio of sulfate in the precipitate to carbon in cellulose is 1: 1.1-1.5.

Technical Field

The invention relates to the technical field of rare earth, in particular to a method for extracting rare earth oxide from rare earth ore.

Background

Rare earth elements are also called rare earths, and refer to an element group formed by 17 elements of scandium, yttrium, lanthanum to lutetium, which have unique magnetic, optical, electrical, and other properties, have extremely wide applications in the industrial field, and are called "industrial vitamins". According to the difference of physicochemical properties of rare earth elements, the rare earth elements are divided into light, medium and heavy rare earths, wherein the medium and heavy rare earths such as europium, terbium, dysprosium and the like have small reserves, large gaps, high values and small replaceability, and at present, the medium and heavy rare earths mainly come from ion adsorption type rare earth ores in China, so that the efficient development of the ion type rare earth ores is of great importance. Although various processes for recovering rare earth have been disclosed at present, the problems of low leaching rate, low recovery rate and purity and the like still exist.

Disclosure of Invention

Based on the technical problems in the background art, the invention provides a method for extracting rare earth oxide from rare earth ore, which has high recovery rate of rare earth and high purity of the obtained rare earth product.

The invention provides a method for extracting rare earth oxide from rare earth ore, which comprises the following steps:

s1, mixing the rare earth ore and water according to the proportion of 1: 3-5, adding ammonium chloride, magnesium sulfate and hydrogen peroxide, stirring for 5-7h, standing for 8-13h, and performing solid-liquid separation to obtain a leaching solution A and a leaching residue A;

s2, filling the leaching residue A into a leaching column, leaching by using a leaching agent A, and leaching by using a leaching agent B to obtain a leaching solution B and a leaching residue B; wherein the leaching agent A is a solution containing magnesium sulfate, chitosan oligosaccharide and polyethylene glycol, the concentration of the magnesium sulfate is 0.07-0.1mol/L, the mass fraction of the chitosan oligosaccharide is 0.5-1.8%, and the mass fraction of the polyethylene glycol is 0.1-1.5%; the leaching agent B is a solution containing potassium sulfate, glycine and pyridine-3-carboxylic acid, wherein the concentration of the potassium sulfate is 0.15-0.22mol/L, the concentration of the glycine is 0.02-0.05mol/L, and the concentration of the pyridine-3-carboxylic acid is 0.01-0.05 mol/L;

s3, mixing the leaching residue B with water according to the ratio of 1: 1-3, stirring for 30-150min, standing for 10-15h, and mixing with the leachate A and the leachate B after solid-liquid separation to obtain leachate;

s4, mixing the adsorbent with the leachate obtained in the step S3, oscillating and adsorbing for 1-2.5 hours, and desorbing the precipitate to obtain a rare earth pregnant solution; wherein, the raw materials of the adsorbent comprise chlorella, chelating resin and spirulina;

s5, carrying out magnetic treatment on the rare earth rich solution, then adding calcium oxide for precipitation, and carrying out solid-liquid separation to obtain a rare earth precipitate;

s6, mixing the mixed solution containing EDTA and citric acid and the rare earth precipitate, stirring for 10-15min at 30-40 ℃, and after solid-liquid separation, uniformly mixing the obtained precipitate with cellulose and water to obtain slurry with the water content of 38-47 wt%; and (3) after pelletizing the slurry, preserving the temperature for 90-150min at 800-880 ℃ to obtain the rare earth oxide.

Preferably, in S1, the ammonium chloride is used in an amount of 0.5 to 0.9 times by weight of the rare earth oxide contained in the rare earth ore; the dosage of the magnesium sulfate is 2-3 times of the weight of the rare earth oxide contained in the rare earth ore, and the dosage of the hydrogen peroxide is 0.15-0.35 time of the weight of the rare earth oxide contained in the rare earth ore.

Preferably, in S2, the solid-to-liquid ratio of leaching residue A to leaching agent A is 1 kg: 0.2-0.5L; leaching by using leaching agent B until the concentration of the rare earth in the leaching solution is lower than 0.1g/L (calculated as REO).

Preferably, in S2, the flow rates of leachant A and leachant B are each 0.4 to 0.65ml/min during leaching.

Preferably, in S2, the polyethylene glycol is polyethylene glycol 200, polyethylene glycol 1500, polyethylene glycol 2000 in a weight ratio of 2-10: 1-4: 3-9.

Preferably, in S4, the solid-to-liquid ratio of the adsorbent to the leachate is 5-15 g: 1L; the weight ratio of the chlorella to the chelating resin to the spirulina is (1-4): 8-20: 2-7.

Preferably, in S4, the desorbent used in the desorption process is one or more of malic acid, citric acid and hydrochloric acid; the desorption temperature is 40-50 ℃ and the desorption time is 2-5 h.

Preferably, in S5, the magnetic treatment time is 7-18min, and the magnetic field strength is 600-650 kA/m.

Preferably, in S6, in the mixed solution containing EDTA and citric acid, the concentration of EDTA is 0.03-0.07mol/L, and the concentration of citric acid is 0.01-0.05 mol/L; the liquid-solid ratio of the mixed solution containing EDTA and citric acid to the rare earth precipitate is 0.2-1L: 1 kg.

Preferably, in S6, the weight ratio of sulfate in the precipitate to carbon in the cellulose is 1: 1.1-1.5.

Preferably, the rare earth ore is ion adsorption type rare earth ore.

Preferably, the chelating resin may be a chelating resin CR 20; the chelating resin CR20 may be a modified chelating resin CR 20; the modified chelate resin CR20 was prepared according to the following procedure: adding commercially available chelating resin CR20 into diglycolic anhydride ethanol solution, stirring and reacting at 26-30 deg.C for 50-70h, filtering and separating the obtained product, washing with ethanol and water, and drying.

Preferably, in S5, the weight ratio of the calcium oxide to the rare earth content during the calcium oxide addition is 1-1.5: 1.

preferably, in S4, the desorbent used is an aqueous solution of malic acid having a concentration of 0.1 mol/L.

Preferably, in S4, the desorbent used is an aqueous solution of citric acid having a concentration of 0.1 mol/L.

Preferably, in S4, during desorption, the solid-to-liquid ratio is 0.5 to 1L: 5-10 g.

In the method for extracting rare earth oxide from rare earth ore, firstly, ammonium chloride, magnesium sulfate and hydrogen peroxide are used as raw materials to leach rare earth ore, most of easily desorbed hydrated rare earth ions are exchanged and desorbed with cations in a leaching agent, the rare earth ions enter a leaching solution A, and then the leaching residue A obtained is sequentially subjected to the utilization of the solution containing magnesium sulfate, chitosan oligosaccharide and polyethylene glycolThe diol leaching agent A and the leaching agent B containing potassium sulfate, glycine and pyridine-3-carboxylic acid are leached, wherein chitosan oligosaccharide, polyethylene glycol, glycine and pyridine-3-carboxylic acid can be complexed with the hydrated rare earth ions which are difficult to desorb in the rare earth ore to form a stable rare earth complex, so that the enhanced leaching effect is high, the desorption of the rare earth which is difficult to leach is promoted, and the leaching rate of the rare earth in the obtained leaching solution is high; the leachate is adsorbed by using a specific adsorbent, so that the selectivity to rare earth is good, the rare earth is enriched after desorption, and the calcium oxide is used for precipitation after magnetic treatment, so that the precipitation rate and purity of the rare earth are improved; the calcium oxide is used as a precipitator to precipitate rare earth ions, and basic rare earth sulfate precipitates are generated, SO4 in the mixed rare earth oxide obtained by roasting is caused^2-In the invention, the mixed solution containing EDTA and citric acid is firstly mixed with the rare earth precipitate and then stirred, wherein the EDTA and citric acid can react with SO in the basic rare earth sulfate₄ ^2-Competition coordination occurs to make SO₄ ^2-The rare earth oxide is removed and enters the solution, the purity of the obtained product is improved, and then the product is mixed with cellulose and then is pelletized and roasted to reduce sulfate radicals, so that the content of the sulfate radicals in the obtained product is further reduced, and the purity of the obtained rare earth oxide is improved.

Detailed Description

The technical solution of the present invention will be described in detail below with reference to specific examples.

Example 1

The invention provides a method for extracting rare earth oxide from rare earth ore, which comprises the following steps:

s1, mixing the rare earth ore and water according to the proportion of 1: 5, adding ammonium chloride, magnesium sulfate and hydrogen peroxide, stirring for 5 hours, standing for 13 hours, and carrying out solid-liquid separation to obtain a leaching solution A and leaching residues A;

s2, filling the leaching residue A into a leaching column, leaching by using a leaching agent A, and leaching by using a leaching agent B to obtain a leaching solution B and a leaching residue B; the leaching agent A is a solution containing magnesium sulfate, chitosan oligosaccharide and polyethylene glycol, the concentration of the magnesium sulfate is 0.07mol/L, the mass fraction of the chitosan oligosaccharide is 1%, and the mass fraction of the polyethylene glycol is 1.5%; the leaching agent B is a solution containing potassium sulfate, glycine and pyridine-3-carboxylic acid, the concentration of the potassium sulfate is 0.18mol/L, the concentration of the glycine is 0.03mol/L, and the concentration of the pyridine-3-carboxylic acid is 0.01 mol/L;

s3, mixing the leaching residue B with water according to the ratio of 1: 1, stirring for 150min, standing for 11h, carrying out solid-liquid separation, and then combining with the leaching solution A and the leaching solution B to obtain a leaching solution;

s4, mixing the adsorbent with the leachate obtained in the step S3, oscillating and adsorbing for 2.5 hours, and desorbing the precipitate to obtain a rare earth rich solution; wherein, the raw materials of the adsorbent comprise chlorella, chelating resin and spirulina;

s5, carrying out magnetic treatment on the rare earth rich solution, then adding calcium oxide for precipitation, and carrying out solid-liquid separation to obtain a rare earth precipitate;

s6, mixing the mixed solution containing EDTA and citric acid and the rare earth precipitate, stirring for 15min at 30 ℃, and after solid-liquid separation, uniformly mixing the obtained precipitate with cellulose and water to obtain slurry with the water content of 38 wt%; and (3) after pelletizing the slurry, preserving the temperature for 90min at 880 ℃ to obtain the rare earth oxide.

Example 2

The invention provides a method for extracting rare earth oxide from rare earth ore, which comprises the following steps:

s1, mixing the rare earth ore and water according to the proportion of 1: 3, adding ammonium chloride, magnesium sulfate and hydrogen peroxide, stirring for 7 hours, standing for 8 hours, and performing solid-liquid separation to obtain a leaching solution A and leaching residues A; wherein the dosage of the ammonium chloride is 0.9 time of the weight of the rare earth oxide contained in the rare earth ore; the dosage of the magnesium sulfate is 2 times of the weight of the rare earth oxide contained in the rare earth ore, and the dosage of the hydrogen peroxide is 0.15 times of the weight of the rare earth oxide contained in the rare earth ore;

s2, putting the leaching residue A into a leaching column, leaching by using a leaching agent A, and then leaching by using a leaching agent B until the rare earth concentration in the leaching solution is 0.08g/L to obtain a leaching solution B and a leaching residue B; wherein the solid-to-liquid ratio of the leaching residue A to the leaching agent A is 1 kg: 0.3L; the leaching agent A is a solution containing magnesium sulfate, chitosan oligosaccharide and polyethylene glycol, the concentration of the magnesium sulfate is 0.1mol/L, the mass fraction of the chitosan oligosaccharide is 0.5%, and the mass fraction of the polyethylene glycol is 0.7%; the leaching agent B is a solution containing potassium sulfate, glycine and pyridine-3-carboxylic acid, the concentration of the potassium sulfate is 0.15mol/L, the concentration of the glycine is 0.05mol/L, and the concentration of the pyridine-3-carboxylic acid is 0.05 mol/L; in the leaching process, the flow rates of the leaching agent A and the leaching agent B are both 0.5 ml/min; the polyethylene glycol is polyethylene glycol 200, polyethylene glycol 1500 and polyethylene glycol 2000 in a weight ratio of 10: 1: 9, a mixture thereof;

s3, mixing the leaching residue B with water according to the ratio of 1: 3, stirring for 30min, standing for 15h, carrying out solid-liquid separation, and then combining with the leaching solution A and the leaching solution B to obtain a leaching solution;

s4, mixing the adsorbent with the leachate obtained in the step S3, oscillating and adsorbing for 1h, and desorbing the precipitate to obtain a rare earth rich solution; wherein the solid-to-liquid ratio of the adsorbent to the leachate is 5 g: 1L; the raw materials of the adsorbent comprise chlorella, chelating resin and spirulina, and the weight ratio of the chlorella to the chelating resin to the spirulina is (4): 8: 7; in the desorption process, the desorbent is citric acid; the desorption temperature is 40 ℃, and the time is 5 hours;

s5, carrying out magnetic treatment on the rare earth rich solution for 7min, wherein the magnetic field intensity is 650kA/m, then adding calcium oxide for precipitation, and carrying out solid-liquid separation to obtain rare earth precipitate;

s6, mixing the mixed solution containing EDTA and citric acid and the rare earth precipitate, stirring for 10min at 40 ℃, and after solid-liquid separation, uniformly mixing the obtained precipitate with cellulose and water to obtain slurry with the water content of 45 wt%; after pelletizing the slurry, keeping the temperature at 800 ℃ for 150min to obtain the rare earth oxide; wherein, in the mixed solution containing EDTA and citric acid, the concentration of EDTA is 0.07mol/L, and the concentration of citric acid is 0.01 mol/L; the liquid-solid ratio of the mixed solution containing EDTA and citric acid to the rare earth precipitate is 1L: 1 kg; the weight ratio of sulfate radicals in the precipitate to carbon in the cellulose is 1: 1.1.

example 3

The invention provides a method for extracting rare earth oxide from rare earth ore, which comprises the following steps:

s1, mixing the rare earth ore and water according to the proportion of 1: 3, uniformly mixing, adding ammonium chloride, magnesium sulfate and hydrogen peroxide, stirring for 6 hours, standing for 11 hours, and carrying out solid-liquid separation to obtain a leaching solution A and leaching residues A; wherein the dosage of the ammonium chloride is 0.5 time of the weight of the rare earth oxide contained in the rare earth ore; the dosage of the magnesium sulfate is 3 times of the weight of the rare earth oxide contained in the rare earth ore, and the dosage of the hydrogen peroxide is 0.35 times of the weight of the rare earth oxide contained in the rare earth ore;

s2, putting the leaching residue A into a leaching column, and leaching by using a leaching agent A, wherein the solid-to-liquid ratio of the leaching residue A to the leaching agent A is 1 kg: 0.2L, then leaching by using a leaching agent B until the concentration of the rare earth in the leaching solution is 0.05g/L to obtain a leaching solution B and leaching residues B; wherein the leaching agent A is a solution containing magnesium sulfate, chitosan oligosaccharide and polyethylene glycol, the concentration of the magnesium sulfate is 0.08mol/L, the mass fraction of the chitosan oligosaccharide is 1.8%, and the mass fraction of the polyethylene glycol is 0.1%; the leaching agent B is a solution containing potassium sulfate, glycine and pyridine-3-carboxylic acid, the concentration of the potassium sulfate is 0.22mol/L, the concentration of the glycine is 0.02mol/L, and the concentration of the pyridine-3-carboxylic acid is 0.03 mol/L; in the leaching process, the flow rates of the leaching agent A and the leaching agent B are both 0.65 ml/min; the polyethylene glycol is polyethylene glycol 200, polyethylene glycol 1500 and polyethylene glycol 2000 in a weight ratio of 2: 4: 3;

s3, mixing the leaching residue B with water according to the ratio of 1: 1, stirring for 90min, standing for 10h, and mixing the solid-liquid separation with the leaching solution A and the leaching solution B to obtain a leaching solution;

s4, mixing an adsorbent with the leachate obtained in the step S3, wherein the solid-to-liquid ratio of the adsorbent to the leachate is 15 g: 1L, oscillating and adsorbing for 2h, and desorbing the precipitate to obtain rare earth pregnant solution; wherein, the raw materials of the adsorbent comprise chlorella, chelating resin and spirulina, and the weight ratio of the chlorella to the chelating resin to the spirulina is 1: 20: 2; in the desorption process, the desorbent is malic acid; the desorption temperature is 50 ℃, and the time is 2 hours;

s5, carrying out magnetic treatment on the rare earth rich solution for 18min, wherein the magnetic field intensity is 600kA/m, then adding calcium oxide for precipitation, and carrying out solid-liquid separation to obtain rare earth precipitate;

s6, mixing the mixed solution containing EDTA and citric acid and the rare earth precipitate, stirring for 12min at 35 ℃, and after solid-liquid separation, uniformly mixing the obtained precipitate with cellulose and water to obtain slurry with the water content of 47 wt%; after pelletizing the slurry, keeping the temperature at 850 ℃ for 120min to obtain the rare earth oxide; in the mixed solution containing EDTA and citric acid, the concentration of EDTA is 0.03mol/L, and the concentration of citric acid is 0.05 mol/L; the liquid-solid ratio of the mixed solution containing EDTA and citric acid to the rare earth precipitate is 0.2L: 1 kg; the weight ratio of sulfate radicals in the precipitate to carbon in the cellulose is 1: 1.3.

example 4

The invention provides a method for extracting rare earth oxide from rare earth ore, which comprises the following steps:

s1, mixing the rare earth ore and water according to the proportion of 1: 4, adding ammonium chloride, magnesium sulfate and hydrogen peroxide, stirring for 6 hours, standing for 10 hours, and carrying out solid-liquid separation to obtain a leaching solution A and leaching residues A; wherein the dosage of the ammonium chloride is 0.6 times of the weight of the rare earth oxide contained in the rare earth ore; the dosage of the magnesium sulfate is 3 times of the weight of the rare earth oxide contained in the rare earth ore, and the dosage of the hydrogen peroxide is 0.2 times of the weight of the rare earth oxide contained in the rare earth ore;

s2, putting the leaching residue A into a leaching column, and leaching by using a leaching agent A, wherein the solid-to-liquid ratio of the leaching residue A to the leaching agent A is 1 kg: 0.5L, then leaching by using a leaching agent B until the concentration of the rare earth in the leaching solution is 0.02g/L to obtain a leaching solution B and leaching residues B; wherein the leaching agent A is a solution containing magnesium sulfate, chitosan oligosaccharide and polyethylene glycol, the concentration of the magnesium sulfate is 0.08mol/L, the mass fraction of the chitosan oligosaccharide is 1.5%, and the mass fraction of the polyethylene glycol is 0.5%; the leaching agent B is a solution containing potassium sulfate, glycine and pyridine-3-carboxylic acid, the concentration of the potassium sulfate is 0.2mol/L, the concentration of the glycine is 0.04mol/L, and the concentration of the pyridine-3-carboxylic acid is 0.045 mol/L; in the leaching process, the flow rates of the leaching agent A and the leaching agent B are both 0.4 ml/min; the polyethylene glycol is polyethylene glycol 200, polyethylene glycol 1500 and polyethylene glycol 2000 in a weight ratio of 7: 2: 6;

s3, mixing the leaching residue B with water according to the ratio of 1: 2, stirring for 60min, standing for 14h, and mixing the solid-liquid separation with the leaching solution A and the leaching solution B to obtain a leaching solution;

s4, mixing an adsorbent with the leachate obtained in the step S3, wherein the solid-to-liquid ratio of the adsorbent to the leachate is 8 g: 1L, oscillating and adsorbing for 1.5h, and desorbing the precipitate to obtain rare earth pregnant solution; wherein, the raw materials of the adsorbent comprise chlorella, chelating resin and spirulina, and the weight ratio of the chlorella to the chelating resin to the spirulina is 2: 9: 4; in the desorption process, the desorbent is a mixture of malic acid and hydrochloric acid; the desorption temperature is 42 ℃, and the time is 4 hours;

s5, carrying out magnetic treatment on the rare earth rich solution for 9min, wherein the magnetic field intensity is 630kA/m, then adding calcium oxide for precipitation, and carrying out solid-liquid separation to obtain rare earth precipitate;

s6, mixing the mixed solution containing EDTA and citric acid and the rare earth precipitate, stirring for 12min at 38 ℃, and after solid-liquid separation, uniformly mixing the obtained precipitate with cellulose and water to obtain slurry with the water content of 45 wt%; after pelletizing the slurry, keeping the temperature at 820 ℃ for 130min to obtain the rare earth oxide; wherein, in the mixed solution containing EDTA and citric acid, the concentration of EDTA is 0.04mol/L, and the concentration of citric acid is 0.04 mol/L; the liquid-solid ratio of the mixed solution containing EDTA and citric acid to the rare earth precipitate is 0.4L: 1 kg; the weight ratio of sulfate radicals in the precipitate to carbon in the cellulose is 1: 1.5.

example 5

The invention provides a method for extracting rare earth oxide from rare earth ore, which comprises the following steps:

s1, mixing the rare earth ore and water according to the proportion of 1: 3.5, adding ammonium chloride, magnesium sulfate and hydrogen peroxide, stirring for 5.5 hours, standing for 9 hours, and carrying out solid-liquid separation to obtain a leaching solution A and a leaching residue A; wherein the dosage of the ammonium chloride is 0.8 time of the weight of the rare earth oxide contained in the rare earth ore; the dosage of the magnesium sulfate is 2 times of the weight of the rare earth oxide contained in the rare earth ore, and the dosage of the hydrogen peroxide is 0.3 times of the weight of the rare earth oxide contained in the rare earth ore;

s2, putting the leaching residue A into a leaching column, and leaching by using a leaching agent A, wherein the solid-to-liquid ratio of the leaching residue A to the leaching agent A is 1 kg: 0.26L, and then leaching by using a leaching agent B until the concentration of the rare earth in the leaching solution is 0.03g/L to obtain a leaching solution B and leaching residues B; wherein the leaching agent A is a solution containing magnesium sulfate, chitosan oligosaccharide and polyethylene glycol, the concentration of the magnesium sulfate is 0.09mol/L, the mass fraction of the chitosan oligosaccharide is 0.7%, and the mass fraction of the polyethylene glycol is 1%; the leaching agent B is a solution containing potassium sulfate, glycine and pyridine-3-carboxylic acid, the concentration of the potassium sulfate is 0.17mol/L, the concentration of the glycine is 0.03mol/L, and the concentration of the pyridine-3-carboxylic acid is 0.03 mol/L; in the leaching process, the flow rates of the leaching agent A and the leaching agent B are both 0.4-0.65 ml/min; the polyethylene glycol is polyethylene glycol 200, polyethylene glycol 1500 and polyethylene glycol 2000 in a weight ratio of 3: 3: 5 with a mixture of;

s3, mixing the leaching residue B with water according to the ratio of 1: 1.5, stirring for 120min, standing for 12h, carrying out solid-liquid separation, and then combining with the leaching solution A and the leaching solution B to obtain a leaching solution;

s4, mixing an adsorbent with the leachate obtained in the step S3, wherein the solid-to-liquid ratio of the adsorbent to the leachate is 12 g: 1L, oscillating and adsorbing for 2h, and desorbing the precipitate to obtain rare earth pregnant solution; wherein, the raw materials of the adsorbent comprise chlorella, chelating resin and spirulina, and the weight ratio of the chlorella to the chelating resin to the spirulina is 3: 17: 5; in the desorption process, the used desorbent is hydrochloric acid; the desorption temperature is 48 ℃, and the time is 3 hours;

s5, carrying out magnetic treatment on the rare earth rich solution for 15min, wherein the magnetic field intensity is 620kA/m, then adding calcium oxide for precipitation, and carrying out solid-liquid separation to obtain rare earth precipitate;

s6, mixing the mixed solution containing EDTA and citric acid and the rare earth precipitate, stirring for 14min at 33 ℃, and after solid-liquid separation, uniformly mixing the obtained precipitate with cellulose and water to obtain slurry with the water content of 40 wt%; pelletizing the slurry, and then preserving the temperature for 110min at 850 ℃ to obtain the rare earth oxide; in the mixed solution containing EDTA and citric acid, the concentration of EDTA is 0.06mol/L, and the concentration of citric acid is 0.02 mol/L; the liquid-solid ratio of the mixed solution containing EDTA and citric acid to the rare earth precipitate is 0.8L: 1 kg; the weight ratio of sulfate radicals in the precipitate to carbon in the cellulose is 1: 1.3.

comparative example 1

The only difference from example 5 is that: magnesium sulfate was not contained in S1.

Comparative example 2

The only difference from example 5 is that: in S2, the leaching agent a is a solution containing magnesium sulfate, but not chitosan oligosaccharide and polyethylene glycol.

Comparative example 3

The only difference from example 5 is that: in S2, the leaching agent a is a solution containing chitosan oligosaccharide and polyethylene glycol, and does not contain magnesium sulfate.

Comparative example 4

The only difference from example 5 is that: in S2, the leaching agent B is a solution containing potassium sulfate and is free of glycine and pyridine-3-carboxylic acid.

Comparative example 5

The only difference from example 5 is that: in S2, the leaching agent B is a solution containing glycine and pyridine-3-carboxylic acid, but no potassium sulfate.

Comparative example 6

The only difference from example 5 is that: in S4, the raw material of the adsorbent includes a chelate resin, and does not include chlorella and spirulina.

Comparative example 7

The only difference from example 5 is that: in S4, the raw material of the adsorbent includes chlorella and spirulina, and does not include a chelating resin.

Comparative example 8

The only difference from example 5 is that: in S5, no magnetic treatment is performed.

Comparative example 9

The only difference from example 5 is that: in S6, directly keeping the rare earth precipitate obtained in S5 at 850 ℃ for 110min to obtain the rare earth oxide.

Comparative example 10

The only difference from example 5 is that: in S6, the solution containing citric acid and the rare earth precipitate are mixed and stirred at 33 ℃ for 14 min.

Comparative example 11

The only difference from example 5 is that: in S6, the EDTA-containing solution and the rare earth precipitate were mixed and stirred at 33 ℃ for 14 min.

In example 5 of the invention, the leaching rate of the rare earth in the obtained leaching solution is 99.6%, the recovery rate of the rare earth reaches 98.9%, and the purity of the rare earth oxide is 96.8%; in comparative examples 1 to 5, the leaching rate of rare earth in the leachate is 93.9 to 95.7 percent; while the recovery rate of rare earth in comparative examples 6-11 was 87.1-91.6%, and the purity of rare earth oxide was less than 93.8%.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.