A leaching agent and its application, and a method for exploiting ion-type rare earth ore

Abstract

The present application belongs to the technical field of mining, and particularly relates to a leaching agent and application thereof, and a method for exploiting ion-type rare earth ore. The leaching agent provided by the present application comprises a main leaching agent and an auxiliary leaching agent; the auxiliary leaching agent is a benzoate salt having the same cation as the main leaching agent. The present application uses the leaching agent to leach ion-type rare earth ore, and the obtained rare earth leaching mother liquor and a precipitant are mixed to perform precipitation, and then solid-liquid separation is performed to obtain supernatant and rare earth precipitate, respectively; the supernatant is recycled and used as water for preparing the leaching agent; the rare earth precipitate is subjected to acid dissolution with hydrochloric acid, and then solid-liquid separation is performed to obtain a chlorinated rare earth solution and benzoic acid; the obtained benzoate salt can be reused as the auxiliary leaching agent by mixing the benzoate salt with an alkaline solution to perform a neutralization reaction. The present application can efficiently leach rare earth while effectively inhibiting aluminum leaching, and the leaching agent ions that are not used during leaching can be returned to the mine for reuse, thereby avoiding the introduction of new non-rare earth impurities in the process of exploiting ion-type rare earth while inhibiting aluminum.

Description

Technical Field

[0001] This invention belongs to the field of mining technology, specifically relating to a leaching agent and its application, and a method for mining ion-adsorption rare earth minerals. Background Technology

[0002] Ion-adsorption rare earth minerals are a special type of rare earth mineral. Rare earth elements in the ore primarily exist in the ionic phase, therefore ion exchange leaching is commonly used for extraction. However, during ion-adsorption rare earth leaching, other ionic phases of non-rare earth elements on the surface of the rare earth minerals are also leached out, with aluminum ions being the most abundant. The impact of aluminum ions on ion-adsorption rare earth mining is mainly reflected in two aspects: First, the high aluminum content in ion-adsorption rare earth minerals increases the consumption of leaching agents during leaching, raising production costs. Second, aluminum and rare earth elements are both trivalent ions with similar properties. During rare earth extraction and separation, aluminum ions compete with rare earth ions for extraction, reducing the extraction capacity of the extractant. Furthermore, a high aluminum ion content easily leads to emulsification during extraction, affecting the stability of the extraction process. Therefore, the separation process of aluminum and rare earth ions in ion-adsorption rare earth mining is a crucial step in reducing mining costs and ensuring the quality of the mineral products.

[0003] To reduce the aluminum content in rare earth leaching solutions, existing processes include aluminum-suppressing leaching and post-leaching aluminum removal. Researchers have proposed adding aluminum inhibitors to ionic rare earth leaching agents to suppress aluminum ion leaching during the leaching process, thereby obtaining a rare earth leaching mother liquor with a lower aluminum ion content. Chinese patent CN103526014A, "Method for Suppressing Aluminum Leaching of Weathered Crust Eluent Rare Earth Ores," describes a process that uses ammonium sulfate, ammonium chloride, or a combination of both as a composite leaching agent to leach weathered crust eluting rare earth ores, achieving good aluminum ion suppression. While acetate as an aluminum inhibitor can selectively suppress aluminum ion leaching during the leaching process, its addition increases the cost of leaching reagents. Furthermore, the acetate, sodium, and potassium ions in the aluminum inhibitor can become new sources of impurity ions in the rare earth leaching mother liquor.

[0004] Aluminum removal from the leachate after in-situ leaching of ion-type rare earth minerals is mainly achieved through precipitation. A precipitant is added to the rare earth leaching mother liquor, and under controlled reaction conditions, aluminum ions are selectively converted into water-insoluble aluminum salts that precipitate. The supernatant is then separated from the precipitate using methods such as plate and frame filtration, thus purifying the rare earth leaching mother liquor and removing aluminum. This process is simple to operate and uses readily available raw materials, making it a commonly used aluminum removal process in mining areas. Regarding the selection of precipitants, there are neutralizing precipitants that utilize the difference in solubility product to adjust the pH of the solution, converting aluminum ions into aluminum hydroxide. These precipitants are generally weak bases, such as ammonium bicarbonate. There are also specific precipitants that can selectively precipitate aluminum ions without reacting with rare earth ions, such as the benzoate precipitant mentioned in Chinese patent CN102965506A, "Method for Removing Aluminum from Rare Earth Solution by Benzoate Precipitation," which can selectively precipitate aluminum ions from rare earth solutions. In neutralization precipitants, since rare earth hydroxides are also a type of precipitate, theoretically, the pH value needs to be controlled between 4.5 and 5.0 to remove aluminum ions while minimizing the loss of rare earth ions during the neutralization precipitation process. However, precise control is difficult to achieve in practice, easily leading to poor aluminum ion removal or the formation of rare earth hydroxide precipitates, resulting in a loss of rare earth yield. Meanwhile, aluminum hydroxide is a colloidal precipitate with a high water content after pressure filtration, which also carries away some of the rare earth from the mother liquor. Furthermore, this process generates a large amount of precipitate residue that requires harmless treatment, increasing subsequent environmental disposal costs and wasting aluminum resources. While specific precipitants such as benzoates have good selective precipitation effects on aluminum in rare earth solutions, they also face the problem of precipitate residue disposal, resulting in further waste of aluminum resources. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a leaching agent and its application, and a method for mining ionic rare earth ores. The leaching agent provided by the present invention can effectively suppress aluminum leaching when mining ionic rare earth ores, will not introduce new non-rare earth impurities into the rare earth chloride solution, and can realize the recycling of the leaching agent during the mining process.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The present invention provides a leaching agent, comprising a primary leaching agent and an auxiliary leaching agent; wherein the auxiliary leaching agent is a benzoate having the same cation as the primary leaching agent.

[0008] Preferably, the main leaching agent includes ammonium sulfate or magnesium sulfate.

[0009] Preferably, the main leaching agent is ammonium sulfate and the auxiliary leaching agent is ammonium benzoate;

[0010] Alternatively, the main leaching agent may be magnesium sulfate and the auxiliary leaching agent may be magnesium benzoate.

[0011] Preferably, the mass ratio of the main leaching agent to the auxiliary leaching agent is (1-3.5):(0.5-1).

[0012] The present invention also provides the application of the leaching agent described in the above technical solution in the mining of ion-adsorption rare earth ores.

[0013] This invention also provides a method for mining ion-adsorption rare earth minerals, comprising the following steps:

[0014] The leaching agent solution described in the above technical solution is used to leach ion-type rare earth ore to obtain rare earth leaching mother liquor;

[0015] The rare earth leaching mother liquor and the precipitant are mixed for precipitation, and the solid and liquid are separated to obtain the supernatant and rare earth precipitate, respectively.

[0016] The rare earth precipitate was mixed with hydrochloric acid and subjected to an acid dissolution reaction. Solid-liquid separation was then performed to obtain a rare earth chloride solution and benzoic acid filter residue, respectively.

[0017] The precipitant and the main leaching agent have the same cations;

[0018] The benzoic acid filter residue is mixed with an alkaline solution for a neutralization reaction, and the resulting benzoate solution is reused as an auxiliary leaching agent.

[0019] Preferably, the total mass percentage of the main leaching agent and auxiliary leaching agent in the leaching agent solution is 2-4%.

[0020] Preferably, the volume ratio of the leaching agent solution to the mass ratio of the ionic rare earth ore is (0.7-2) mL:1 g.

[0021] Preferably, the precipitant is ammonium bicarbonate or magnesium oxide.

[0022] Preferably, the mass of the precipitant is 1.5 to 3.5 times the mass of the rare earth oxides obtained by converting rare earth ions in the rare earth leaching mother liquor.

[0023] This invention provides a leaching agent, comprising a primary leaching agent and an auxiliary leaching agent; the auxiliary leaching agent is a benzoate having the same cation as the primary leaching agent. In this invention, benzoate can react with aluminum ions but not with rare earth ions to form a precipitate. By using benzoate with the same cation as the primary leaching agent as the auxiliary leaching agent to form the leaching agent together with the primary leaching agent, the benzoate anion (benzoate ion) can solidify the aluminum ions obtained from exchange leaching into the ore body by precipitation, avoiding waste of aluminum resources. The benzoate cation serves as a supplement to the cation of the ionic rare earth primary leaching agent, correspondingly reducing the amount of primary leaching agent used, and the overall cost of the leaching agent does not increase significantly. The benzoate that does not participate in the aluminum-suppressing leaching reaction enters the rare earth leaching mother liquor. Since the cation is the same as the primary leaching agent cation, the influence of the benzoate anion on subsequent processes is mainly considered. Benzoate ions do not react with the precipitant during rare earth precipitation; the vast majority remain in the supernatant and can be returned to the mine for reuse as leaching agent preparation water. Due to the presence of water, a small amount of benzoate ions may also be carried in the rare earth precipitation. These benzoate ions are converted into water-insoluble benzoic acid through rare earth acid solubilization and can be removed by filtration. This entire process avoids the introduction of new non-rare earth impurities during ion-modified rare earth aluminum suppression mining. The benzoic acid obtained from filtration is then reacted with an alkaline solution to obtain benzoate salts, which can be used as an auxiliary leaching agent. Attached Figure Description

[0024] Figure 1 This is a flowchart of a method for mining ion-adsorption rare earth minerals in an embodiment of the present invention. Detailed Implementation

[0025] The present invention provides a leaching agent, comprising a primary leaching agent and an auxiliary leaching agent; wherein the auxiliary leaching agent is a benzoate having the same cation as the primary leaching agent.

[0026] In this invention, the auxiliary leaching agent is a benzoate having the same cation as the main leaching agent; the main leaching agent preferably includes ammonium sulfate or magnesium sulfate, more preferably magnesium sulfate. Preferably, the main leaching agent is ammonium sulfate and the auxiliary leaching agent is ammonium benzoate, or the main leaching agent is magnesium sulfate and the auxiliary leaching agent is magnesium benzoate. The ion-type rare earth leaching process mainly involves ion exchange between the cations in the leaching agent and rare earth ions to leach out the rare earth ions.

[0027] This invention utilizes the selective precipitation of aluminum ions by benzoates without precipitating rare earth ions. It adds benzoates as aluminum inhibitors to leaching agents to suppress aluminum ion leaching without affecting rare earth ion leaching. By selecting benzoates with the same cation as the main leaching agent, it can supplement the main leaching agent, thus reducing the amount of the main leaching agent used. In ion-type rare earth leaching, cations in the leaching agent exchange ions with rare earth ions; therefore, the amount of rare earth leached depends on the number of cations in the leaching agent. Assuming the same rare earth leaching rate, if the auxiliary leaching agent has the same cation as the main leaching agent, the amount of the main leaching agent can be reduced accordingly.

[0028] In this invention, the preferred mass ratio of the main leaching agent to the auxiliary leaching agent is (1-3.5):(0.5-1), and more preferably (1.5-3):(0.6-0.8).

[0029] The present invention uses the above-mentioned ratio of leaching agent and auxiliary leaching agent, which can avoid the poor aluminum leaching effect caused by too low a benzoate addition, and also avoid the situation where too high a benzoate addition leads to a faster rate of aluminum benzoate formation between benzoate and aluminum ions, resulting in aluminum benzoate precipitation adhering to the surface of clay minerals, which is not conducive to the exchange and leaching of rare earth ions and reduces the leaching rate of rare earths.

[0030] The present invention also provides the application of the leaching agent described in the above technical solution in the mining of ion-adsorption rare earth ores.

[0031] This invention provides a method for mining ion-adsorption rare earth minerals, comprising the following steps:

[0032] The leaching agent solution described in the above technical solution is used to leach ion-type rare earth ore to obtain rare earth leaching mother liquor;

[0033] The rare earth leaching mother liquor and the precipitant are mixed for precipitation, and the solid and liquid are separated to obtain the supernatant and rare earth precipitate, respectively.

[0034] The rare earth precipitate was mixed with hydrochloric acid and subjected to an acid dissolution reaction. Solid-liquid separation was then performed to obtain a rare earth chloride solution and benzoic acid filter residue, respectively.

[0035] The precipitant and the main leaching agent have the same cations;

[0036] The benzoic acid filter residue is mixed with an alkaline solution for a neutralization reaction, and the resulting benzoate solution is reused as an auxiliary leaching agent.

[0037] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0038] This invention involves leaching ion-type rare earth ores with a leaching agent solution to obtain rare earth leaching mother liquor.

[0039] In this invention, the leaching agent solution is preferably prepared by mixing the leaching agent and water; the total mass percentage of the main leaching agent and auxiliary leaching agent in the leaching agent solution is preferably 2-4%, more preferably 2.5-3.5%; the volume ratio of the leaching agent solution to the mass of the ion-adsorption rare earth ore is preferably (0.7-2) mL:1g, more preferably (1-1.5) mL:1g; the volume ratio of the leaching agent solution to the mass of the ion-adsorption rare earth ore is 1 mL:1g.

[0040] In this invention, the leaching is preferably carried out in situ leaching; the in situ leaching includes the following steps: injecting a solution of the leaching agent into the injection hole or injection well of the ion-adsorption rare earth ore for leaching, and collecting the rare earth leaching mother liquor through one or more of the following: collection tunnel, guide hole and collection ditch.

[0041] The present invention does not impose any special limitations on the setting of the injection holes, injection wells, liquid collection tunnels, diversion holes and liquid collection ditches, and can set them using methods well known in the art.

[0042] After obtaining the rare earth leaching mother liquor, the present invention mixes the rare earth leaching mother liquor and a precipitant for precipitation, and separates the solid and liquid to obtain the supernatant and rare earth precipitate respectively.

[0043] In this invention, the precipitant and the main leaching agent have the same cation; the precipitant is preferably ammonium bicarbonate or magnesium oxide, more preferably magnesium oxide; the mass of the precipitant is preferably 1.5 to 3.5 times the mass of rare earth oxides obtained by converting rare earth ions in the rare earth leaching mother liquor, more preferably 2 to 3 times.

[0044] In this invention, the solid-liquid separation is preferably filtration; the filtration method is preferably vacuum filtration, plate and frame filtration or centrifuge drying, and more preferably plate and frame filtration.

[0045] In this invention, the supernatant is preferably reused as water for preparing the leaching agent solution, and the residual leaching agent in the supernatant can be reused.

[0046] After obtaining the rare earth precipitate, the present invention mixes the rare earth precipitate with hydrochloric acid to carry out an acid dissolution reaction, and then separates the solid and liquid to obtain a rare earth chloride solution and benzoic acid filter residue.

[0047] In this invention, the concentration of hydrochloric acid is preferably 4-6 mol / L, more preferably 4.5-5.5 mol / L; the amount of hydrochloric acid added is preferably controlled to control the pH value of the solution obtained by completely dissolving the rare earth precipitate to be 2.5-4.0, more preferably 3-3.5.

[0048] In this invention, the solid-liquid separation is preferably filtration; the filtration method is preferably vacuum filtration, plate and frame filtration or centrifuge drying, and more preferably plate and frame filtration.

[0049] After obtaining the benzoic acid filter residue, the present invention mixes the benzoic acid filter residue with an alkaline solution for a neutralization reaction, and the resulting benzoate solution is reused as an auxiliary leaching agent.

[0050] In this invention, the alkaline solution is preferably ammonia or magnesium hydroxide solution; the mass concentration of the ammonia is preferably 10-20%, more preferably 12-16%; the mass concentration of the magnesium hydroxide solution is preferably 1-10%, more preferably 2-4%; the molar ratio of benzoic acid in the benzoic acid filter residue to the cations in the alkaline solution is preferably 1.2-1.5:1, more preferably 1.3-1.4:1.

[0051] In this invention, the solid-liquid separation is preferably filtration; the filtration method is preferably vacuum filtration, plate and frame filtration or centrifuge drying, and more preferably plate and frame filtration.

[0052] Before mixing the benzoic acid filter residue with the alkaline solution, the present invention preferably cleans the benzoic acid filter residue; the cleaning reagent is preferably water; the number of cleanings is preferably 1 to 4 times, more preferably 2 to 3 times; the present invention removes rare earth chloride solution entrained in the benzoic acid filter residue by cleaning.

[0053] In this invention, benzoate remaining in the rare earth precipitate (rare earth carbonate or rare earth hydroxide) after the rare earth leaching mother liquor is converted into water-insoluble benzoic acid through hydrochloric acid chlorination, using the mechanism of strong acid to prepare weak acid. The benzoate is then removed by filtration. This not only enables the recycling of benzoic acid but also solves the problem of introducing new non-rare earth impurities during the ion-type rare earth aluminum leaching conversion process.

[0054] In ionic rare earth mining, aluminum and rare earth ions are leached together, leading to the need for separate aluminum removal from the rare earth leaching mother liquor. This invention addresses this issue by adding benzoate as an aluminum inhibitor as an auxiliary leaching agent, resulting in better aluminum inhibition during leaching. This invention uses benzoate with the same cation as the main leaching agent as the auxiliary leaching agent, eliminating the problem of introducing cationic impurities during mining. Benzoate is converted to benzoic acid during the acid dissolution transformation of rare earth precipitates and removed by filtration. The introduction of anionic impurities is also resolved, resulting in no new non-rare earth impurities introduced into the obtained rare earth chloride solution. Benzoate that does not participate in the aluminum inhibition leaching process enters the rare earth leaching mother liquor and does not participate in subsequent rare earth precipitation reactions. Therefore, most of the benzoate remains in the supernatant after precipitation and is returned to the mine for use as a leaching agent in water recycling. A small amount of benzoate remaining in the rare earth precipitates is converted to water-insoluble benzoic acid through subsequent acid dissolution, separated by filtration from the rare earth chloride solution, and then reacted with an alkaline solution to obtain ammonium benzoate or magnesium benzoate solution for reuse as an auxiliary leaching agent.

[0055] Figure 1 This is a flowchart illustrating the method for mining ion-adsorption rare earth ores according to an embodiment of the present invention. Figure 1 As shown, this invention uses a leaching solution composed of a main leaching agent, an auxiliary leaching agent, and water to leach ion-adsorption rare earth ores. The resulting rare earth leaching mother liquor is mixed with a precipitant (ammonium bicarbonate or magnesium oxide) for precipitation. After filtration, a supernatant and a rare earth precipitate (rare earth carbonate or rare earth hydroxide) are obtained. The rare earth precipitate is dissolved in hydrochloric acid, and after filtration, a rare earth chloride solution and benzoic acid are obtained. The benzoic acid is then neutralized by mixing with an alkaline solution (ammonia or magnesium hydroxide solution) to obtain benzoate, which can be reused as an auxiliary leaching agent.

[0056] This invention uses benzoate to solidify aluminum in ion-type rare earth ores within the ore body, avoiding the aluminum removal process required after aluminum ions and rare earth ions are leached out together. The solidified aluminum resources in the ore body can be used for future mining, reducing mining costs and minimizing the waste of aluminum resources.

[0057] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0058] The effect of benzoate as an auxiliary leaching agent on inhibiting aluminum leaching was verified by simulating the leaching environment of an ion-adsorption rare earth ore area using an indoor column leaching test. The completely weathered ore soil from an ion-adsorption rare earth ore area was naturally air-dried, passed through a 20-mesh sieve, and the sieved ore soil was mixed evenly for later use.

[0059] Example 1

[0060] 1000g of pretreated ion-adsorption rare earth ore was weighed and compacted in stages into ion exchange columns of the same diameter. The experimental group used ammonium sulfate + ammonium benzoate leaching agent, while the control group used ammonium sulfate leaching agent. The liquid-solid ratio (volume-mass ratio) of the leaching agent solution to the ore was controlled at 1mL:1g, and the mass concentration of the leaching agent was 2wt.%. The mass ratio of ammonium sulfate to ammonium benzoate in the leaching agent solution of the experimental group was 1.5:0.5. After leaching, the rare earth concentration and aluminum ion concentration in the rare earth leaching mother liquor of the experimental group and the control group were measured respectively.

[0061] The comparative experiment revealed that the collected volumes of rare earth leaching mother liquor in the experimental group and the control group were 682.3 mL and 674.5 mL, respectively. The concentrations of rare earth and aluminum ions in the rare earth leaching mother liquor of the experimental group were 1143.5 mg / L and 112.3 mg / L, respectively, while those in the control group were 1203.4 mg / L and 845.6 mg / L, respectively. The calculated leaching amounts of rare earth in the experimental group and the control group were 780.2 mg and 811.7 mg, respectively, with the leaching amount of rare earth in the experimental group being 96.12% of that in the control group. The leaching amounts of aluminum ions in the experimental group and the control group were 76.6 mg and 570.4 mg, respectively, with the leaching amount of aluminum ions in the experimental group being only 13.4% of that in the control group. Under the condition of comparable rare earth leaching effects, the combined leaching agent of ammonium sulfate and ammonium benzoate showed a significant aluminum inhibition effect in the ion-type rare earth leaching process.

[0062] Ammonium bicarbonate is added to the rare earth leaching mother liquor to precipitate rare earth oxides (REO) calculated from rare earth ions in the mother liquor. The mixture is then filtered using a plate and frame filter press. The supernatant is returned as water for preparing the leaching agent solution. The resulting rare earth carbonate precipitate is dissolved and transformed by adding 4 mol / L hydrochloric acid. The addition of hydrochloric acid is stopped when the rare earth carbonate is completely dissolved and the pH value stabilizes at 3. Plate and frame filter press is then performed to obtain rare earth chloride solution and benzoic acid filter residue. The benzoic acid filter residue is washed with water to remove the entrained rare earth chloride solution. Then, ammonia water with a molar mass of 1.2 times that of benzoic acid is added to neutralize it and generate ammonium benzoate, which can be returned to the mining area as an auxiliary leaching agent.

[0063] Example 2

[0064] 1000g of pretreated ion-adsorption rare earth ore was weighed and compacted in stages into ion exchange columns of the same diameter. The experimental group used magnesium sulfate + magnesium benzoate leaching agent, while the control group used magnesium sulfate leaching agent. The liquid-solid ratio (volume-mass ratio) of the leaching agent solution to the ore was controlled at 1.3mL:1g, and the mass concentration of the leaching agent was 3wt.%. The mass ratio of ammonium sulfate to ammonium benzoate in the leaching agent solution of the experimental group was 2:1. After leaching, the rare earth concentration and aluminum ion concentration in the rare earth leaching mother liquor of the experimental group and the control group were measured respectively.

[0065] The comparative experiments revealed that the collected volumes of rare earth leaching mother liquor in the experimental group and the control group were 968.8 mL and 969.6 mL, respectively. The concentrations of rare earth and aluminum ions in the rare earth leaching mother liquor of the experimental group were 843.5 mg / L and 83.3 mg / L, respectively, while those in the control group were 856.4 mg / L and 687.9 mg / L, respectively. The calculated leaching amounts of rare earth in the experimental group and the control group were 817.2 mg and 830.4 mg, respectively, with the leaching amount of rare earth in the experimental group being 98.41% of that in the control group. The leaching amounts of aluminum ions in the experimental group and the control group were 80.7 mg and 666.99 mg, respectively, with the leaching amount of aluminum ions in the experimental group being only 12.1% of that in the control group. Under the condition of comparable rare earth leaching effects, the combined leaching agent of magnesium sulfate + magnesium benzoate has a significant aluminum inhibition effect in the ion-type rare earth leaching process.

[0066] Magnesium oxide precipitate is added to the rare earth leaching mother liquor. The amount of magnesium oxide added is 2.2 times the mass of rare earth oxides (REO) obtained from the conversion of rare earth ions in the rare earth leaching mother liquor. Plate and frame filter press is used, and the supernatant is returned as water for preparing the leaching agent solution. The obtained rare earth carbonate precipitate is dissolved and transformed by adding 6 mol / L hydrochloric acid. When the rare earth carbonate is completely dissolved and the pH value is stable at 2.5, the addition of hydrochloric acid is stopped. Plate and frame filter press is used to obtain rare earth chloride solution and benzoic acid filter residue. After washing away the rare earth chloride solution entrained in the benzoic acid filter residue with water, magnesium hydroxide solution with 1.2 times the molar mass of benzoic acid is added to neutralize it to generate magnesium benzoate, which can be returned to the mining area as an auxiliary leaching agent.

[0067] Example 3

[0068] The difference from Example 1 is that the mass ratio of ammonium sulfate to ammonium benzoate in the leaching agent solution is 2:1, while the rest is the same as in Example 1.

[0069] The comparative experiments revealed that the collected volumes of the rare earth leaching mother liquor in the experimental group and the control group were 678.5 mL and 681.3 mL, respectively. The concentrations of rare earth and aluminum ions in the rare earth leaching mother liquor of the experimental group were 1183.5 mg / L and 83.7 mg / L, respectively, while those in the control group were 1221.9 mg / L and 943.3 mg / L, respectively. The calculated leaching amounts of rare earth in the experimental group and the control group were 803.0 mg and 832.5 mg, respectively, with the leaching amount of rare earth in the experimental group being 96.5% of that in the control group. The leaching amounts of aluminum ions in the experimental group and the control group were 56.8 mg and 642.7 mg, respectively, with the leaching amount of aluminum ions in the experimental group being only 8.8% of that in the control group. Under the condition of comparable rare earth leaching effects, the combined leaching agent of ammonium sulfate and ammonium benzoate showed a significant aluminum suppression effect in the ion-type rare earth leaching process.

[0070] Example 4

[0071] The difference from Example 2 is that the mass ratio of magnesium sulfate to magnesium benzoate in the leaching agent solution is 3:1, while the rest is the same as in Example 2.

[0072] The comparative experiments revealed that the collected volumes of rare earth leaching mother liquor in the experimental group and the control group were 957.3 mL and 959.4 mL, respectively. The concentrations of rare earth and aluminum ions in the rare earth leaching mother liquor of the experimental group were 848.6 mg / L and 121.8 mg / L, respectively, while those in the control group were 853.7 mg / L and 721.9 mg / L, respectively. The calculated leaching amounts of rare earth in the experimental group and the control group were 812.4 mg and 819.0 mg, respectively, with the leaching amount of rare earth in the experimental group being 99.2% of that in the control group. The leaching amounts of aluminum ions in the experimental group and the control group were 116.6 mg and 692.6 mg, respectively, with the leaching amount of aluminum ions in the experimental group being only 16.8% of that in the control group. Under the condition of comparable rare earth leaching effects, the combined leaching agent of magnesium sulfate and magnesium benzoate showed a significant aluminum inhibition effect in the ion-type rare earth leaching process.

[0073] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for mining ion-adsorption rare earth minerals, characterized in that, Includes the following steps: Ion-type rare earth ores are leached with a leaching agent solution to obtain rare earth leaching mother liquor; the leaching agent includes a main leaching agent and an auxiliary leaching agent; the auxiliary leaching agent is a benzoate having the same cation as the main leaching agent; The rare earth leaching mother liquor and the precipitant are mixed for precipitation, and the solid and liquid are separated to obtain the supernatant and rare earth precipitate, respectively; the precipitant and the main leaching agent have the same cation. The rare earth precipitate was mixed with hydrochloric acid and subjected to an acid dissolution reaction. Solid-liquid separation was then performed to obtain a rare earth chloride solution and benzoic acid filter residue, respectively. The benzoic acid filter residue is mixed with an alkaline solution for a neutralization reaction, and the resulting benzoate solution is reused as an auxiliary leaching agent. The main leaching agent includes ammonium sulfate or magnesium sulfate; The mass ratio of the main leaching agent to the auxiliary leaching agent is (1~3.5):(0.5~1); The total mass percentage of the main leaching agent and auxiliary leaching agent in the leaching agent solution is 2-4%. The volume ratio of the leaching agent solution to the mass of the ion-type rare earth ore is (0.7~2) mL:1 g.

2. The method according to claim 1, characterized in that, The main leaching agent is ammonium sulfate and the auxiliary leaching agent is ammonium benzoate; or the main leaching agent is magnesium sulfate and the auxiliary leaching agent is magnesium benzoate.

3. The method according to claim 1, characterized in that, The precipitant is ammonium bicarbonate or magnesium oxide.

4. The method according to claim 1 or 3, characterized in that, The mass of the precipitant is 1.5 to 3.5 times the mass of the rare earth oxides obtained by converting rare earth ions in the rare earth leaching mother liquor.

Images