Leaching agent for weathering crust illuviation type rare earth ore as well as preparation method and application of leaching agent

Abstract

The invention relates to the field of hydrometallurgy. The invention relates to a leaching agent, in particular to a leaching agent for weathering crust illuviation type rare earth ore and a preparation method and application of the leaching agent. In order to strengthen the leaching of medium and heavy rare earth, reduce the waste of resources, ensure the safety of the mine and realize the efficient and low-impurity safe leaching of the weathering crust elution-deposited rare earth ore, the invention provides the leaching agent for the weathering crust elution-deposited rare earth ore as well as the preparation method and the application thereof, so that the leaching of the medium and heavy rare earth is improved while the leaching rate of the rare earth is ensured; the leaching rate of impurity aluminum is reduced, the expansion rate of clay minerals is reduced, and the production safety of mines is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of hydrometallurgy. More specifically, the present invention relates to a leaching agent for weathered crust eluvial rare earth ore, a preparation method thereof, and an application thereof. Background Art

[0002] Rare earth resources are widely used in high-precision and high-tech fields. The exploitation of rare earth resources has attracted worldwide attention, especially for weathered crust eluvial rare earth ore rich in medium and heavy rare earth resources. The content of medium and heavy rare earths in weathered crust eluvial rare earth ore accounts for 70% of the world's total, making up for the deficiency of low content of medium and heavy rare earths in mineral rare earth ore. The ore of weathered crust eluvial rare earth ore is mainly composed of kaolinite, halloysite, chlorite, montmorillonite, illite and other clay minerals formed by the dissociation and weathering of the original rocks of granite and volcanic rocks in an open system with the presence of groundwater, accompanied by quartz sand and rock-forming mineral feldspar. Among them, rare earths are mainly adsorbed on clay minerals in the form of hydrated or hydroxyhydrated ions, and it is difficult to enrich rare earths by conventional beneficiation methods. At present, in industry, in-situ leaching method is usually adopted, adding an electrolyte solution, and obtaining a rare earth-containing solution through an ion exchange reaction, and further recovering rare earths through steps such as impurity removal and precipitation. Taking NH 4+ as an example, its chemical reaction equation can be expressed as:

[0003]

[0004] Weathered crust eluvial rare earth ore is rich in medium and heavy rare earths with extremely high economic and strategic value. Therefore, the enhanced leaching of medium and heavy rare earths is particularly important. During the rare earth leaching process of weathered crust eluvial rare earth ore, impurity ion aluminum will be leached out together with rare earth ions. The content of aluminum ions in the leaching solution directly affects the rare earth recovery process, resulting in increased impurity removal costs and reduced quality of rare earth products. In addition, during the rare earth leaching process of weathered crust eluvial rare earth ore, clay minerals disperse and expand when encountering water. If the liquid injection is improper, it is extremely easy to cause landslides, with certain potential safety hazards. Summary of the Invention

[0005] The purpose of the present invention is to enhance the leaching of medium and heavy rare earths, reduce waste of resources, ensure the safety of the mine, and achieve efficient, low-impurity and safe leaching of weathered crust eluvial rare earth ore. The present invention provides a leaching agent for weathered crust eluvial rare earth ore, a preparation method thereof, and an application thereof, which can improve the leaching of medium and heavy rare earths while ensuring the rare earth leaching rate, reduce the leaching rate of impurity aluminum, and reduce the swelling rate of clay minerals to ensure the production safety of the mine.

[0006] To achieve these and other advantages in accordance with the present invention, there is provided a leaching agent for weathered crust eluvial rare earth ore, comprising:

[0007] A monocarboxylate salt and water, wherein the concentration of the monocarboxylate salt is 0.05 - 0.3 mol / L.

[0008] Furthermore, in the leaching agent for weathered crust eluvial rare earth ore, the monocarboxylate salt is any one or a combination of several of potassium monocarboxylate, magnesium monocarboxylate, calcium monocarboxylate, and ferrous monocarboxylate.

[0009] Furthermore, in the leaching agent for weathered crust eluvial rare earth ore, the general formula of the monocarboxylate salt is R1R2B, where R1 is a hydrocarbon carbon chain with 0, 1, or 2 carbon atoms, R2 is a carboxyl functional group, and B is a metal cation.

[0010] The present invention also provides a preparation method of the above leaching agent, including the following steps:

[0011] S1. Mix a C1 - C3 monocarboxylic acid and a metal hydroxide evenly to obtain a mixture.

[0012] S2. Heat the mixture obtained in S1 to 80 - 100 °C and continuously stir and react for 3 - 5 hours to obtain a monocarboxylate salt.

[0013] S3. Mix the monocarboxylate salt obtained in S2 with water in a proportion to obtain the leaching agent.

[0014] Furthermore, in the preparation method, in S1, the C1 - C3 monocarboxylic acid and the metal hydroxide are mixed in a mass ratio of 1:1 - 1.5.

[0015] The present invention also provides a method for enhancing the leaching of weathered crust eluvial rare earth ore, using the above leaching agent, including the following steps:

[0016] Dry the weathered crust eluvial rare earth ore and place it in a leaching device. Add the leaching agent according to a liquid - solid ratio of 2:1 (mL:g), and add a pH regulator to adjust the pH value to 3.0 - 8.0, and start leaching.

[0017] Furthermore, in the method for enhancing the leaching of weathered crust eluvial rare earth ore, the pH regulator is any one of hydrochloric acid, sulfuric acid, or glacial acetic acid.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The leaching agent of the present invention uses small - molecule monocarboxylate salts. Compared with the leaching effect of traditional leaching agents, it can ensure the rare earth leaching rate while significantly improving the leaching of medium - heavy rare earths, increasing economic benefits. It can also effectively inhibit the leaching of impurity aluminum, reducing the production cost of the subsequent rare earth leaching mother liquor impurity removal process.

[0020] 2. The leaching agent of the present invention can effectively inhibit the swelling of clay minerals during the rare earth leaching process, ensuring the safe production of rare earth mines.

[0021] 3. The leaching agent of the present invention can replace the traditional ammonium salt leaching agent, solving the problem of ammonia nitrogen environmental pollution existing in the traditional ammonium salt leaching process.

[0022] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. Detailed Embodiments

[0023] The following further detailed description of the present invention is made in conjunction with embodiments, so that those skilled in the art can implement it with reference to the text of the specification.

[0024] It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0025] Example 1

[0026] This example provides a method for enhancing the leaching of weathered crust eluvial rare earth ore, and the leaching agent is a potassium formate solution with a concentration of 0.25 mol / L (the number of carbon atoms in R1 is 0).

[0027] Specifically, it includes the following steps:

[0028] Weigh 250.0 g of the dried weathered crust eluvial rare earth ore sample by the quartering method into a glass exchange column. The average rare earth grade of the ore sample is 0.114%. Inject the leaching agent according to a liquid-solid ratio of 2:1 (mL:g), and adjust the solution to pH = 4.0 with hydrochloric acid. Perform column leaching on the weathered crust eluvial rare earth ore to obtain and collect the rare earth leaching solution.

[0029] After the leaching is completed, calculate that the rare earth leaching rate is 86.26%, the impurity aluminum leaching rate is 42.59%, and the rare earth content in the leaching solution is 980.66 μg / g (LREEs = 624.56 μg / g, M&HREEs = 356.10 μg / g).

[0030] Determine the swelling rate of clay minerals:

[0031] Weigh 2.0 g of the vacuum-dried ore sample, keep the pressure at 8.0 MPa, press the sample on a tablet press for 5.0 min, measure the sample length with a vernier caliper, install the sample on an intelligent clay dilatometer, inject the above leaching agent into the instrument, and determine the swelling rate of the ore sample after 8.0 h. The swelling rate of clay minerals is 1.278%.

[0032] Example 2

[0033] This embodiment provides a method for enhanced leaching of weathered crust eluvial rare earth ore. The leaching agent is a magnesium acetate solution with a concentration of 0.20 mol / L (the number of carbon atoms in R1 is 1).

[0034] Specifically, it includes the following steps:

[0035] Weigh 250.0 g of the dried weathered crust eluvial rare earth ore sample by the quartering method and place it in a glass exchange column. The average rare earth grade of the ore sample is 0.114%. Inject the leaching agent according to a liquid-solid ratio of 2:1 (mL:g), and adjust the solution to pH = 4.0 with glacial acetic acid. Conduct column leaching on the weathered crust eluvial rare earth ore, and obtain and collect the rare earth leaching solution.

[0036] After the leaching is completed, calculate that the rare earth leaching rate is 87.06%, the impurity aluminum leaching rate is 35.46%, and the rare earth content in the leaching solution is 989.76 μg / g (LREEs = 629.24 μg / g, M&HREEs = 360.52 μg / g).

[0037] Determine the swelling rate of clay minerals:

[0038] Weigh 2.0 g of the ore sample after vacuum drying, keep the pressure at 8.0 MPa, press the tablet on a tablet press for 5.0 min, measure the sample length with a vernier caliper, install the sample on an intelligent clay swelling instrument, inject the above leaching agent into the instrument, and determine the swelling rate of the ore sample after 8.0 h. The swelling rate of clay minerals is 1.790%.

[0039] Example 3

[0040] This embodiment provides a method for enhanced leaching of weathered crust eluvial rare earth ore. The leaching agent is a mixed solution of calcium acetate with a concentration of 0.20 mol / L (the number of carbon atoms in R1 is 1) and potassium formate with a concentration of 0.10 mol / L (the number of carbon atoms in R1 is 0).

[0041] Specifically, it includes the following steps:

[0042] Weigh 250.0 g of the dried weathered crust eluvial rare earth ore sample by the quartering method and place it in a glass exchange column. The average rare earth grade of the ore sample is 0.114%. Inject the leaching agent according to a liquid-solid ratio of 2:1 (mL:g), and adjust the solution to pH = 4.0 with glacial acetic acid. Conduct column leaching on the weathered crust eluvial rare earth ore, and obtain and collect the rare earth leaching solution.

[0043] After the leaching is completed, calculate that the rare earth leaching rate is 86.24%, the impurity aluminum leaching rate is 37.58%, and the rare earth content in the leaching solution is 980.44 μg / g (LREEs = 626.70 μg / g, M&HREEs = 353.74 μg / g).

[0044] Determination of the swelling rate of clay minerals:

[0045] Weigh 2.0 g of the ore sample after vacuum drying, keep the pressure at 8.0 MPa, press the sample on a tablet press for 5.0 min, measure the length of the sample with a vernier caliper, install the sample on an intelligent clay swelling instrument, inject the above leaching agent into the instrument, and determine the swelling rate of the ore sample after 8.0 h. The swelling rate of the clay mineral is 2.039%.

[0046] Example 4

[0047] This example provides a method for enhancing the leaching of weathered crust eluvial rare earth ore. The leaching agent is a potassium propionate solution with a concentration of 0.15 mol / L (the number of carbon atoms in R1 is 2).

[0048] Specifically, it includes the following steps:

[0049] Weigh 250.0 g of the dried weathered crust eluvial rare earth ore sample by the quartering method into a glass exchange column. The average rare earth grade of the ore sample is 0.114%. Inject the leaching agent according to a liquid-solid ratio of 2:1 (mL:g), and adjust the solution to pH = 4.0 with sulfuric acid. Conduct column leaching on the weathered crust eluvial rare earth ore to obtain and collect the rare earth leaching solution.

[0050] After the leaching is completed, calculate that the rare earth leaching rate is 86.11%, the impurity aluminum leaching rate is 40.37%, and the rare earth content in the leaching solution is 978.96 μg / g (LREEs = 624.54 μg / g, M&HREEs = 354.42 μg / g).

[0051] Determination of the swelling rate of clay minerals:

[0052] Weigh 2.0 g of the ore sample after vacuum drying, keep the pressure at 8.0 MPa, press the sample on a tablet press for 5.0 min, measure the length of the sample with a vernier caliper, install the sample on an intelligent clay swelling instrument, inject the above leaching agent into the instrument, and determine the swelling rate of the ore sample after 8.0 h. The result is 1.311%.

[0053] Example 5

[0054] This example provides a method for enhancing the leaching of weathered crust eluvial rare earth ore. The leaching agent is a mixed solution of 0.25 mol / L potassium propionate (the number of carbon atoms in R1 is 3) and 0.10 mol / L magnesium acetate (the number of carbon atoms in R1 is 1).

[0055] Specifically, it includes the following steps:

[0056] Weigh 250.0 g of the weathered crust eluvial rare earth ore sample after drying by the quartering method and place it in a glass exchange column. The average grade of rare earth in the ore sample is 0.114%. Inject the leaching agent according to a liquid-solid ratio of 2:1 (mL:g), and adjust the solution to pH = 4.0 with sulfuric acid. Conduct column leaching on the weathered crust eluvial rare earth ore, and obtain and collect the rare earth leaching solution.

[0057] After the leaching is completed, calculate that the rare earth leaching rate is 88.11%, the impurity aluminum leaching rate is 35.84%, and the rare earth content in the leaching solution is 1001.70 μg / g (LREEs = 633.43 μg / g, M&HREEs = 368.27 μg / g).

[0058] Determine the swelling rate of clay minerals:

[0059] Weigh 2.0 g of the ore sample after vacuum drying, keep the pressure at 8.0 MPa, press the sample on a tablet press for 5.0 min, measure the sample length with a vernier caliper, install the sample on an intelligent clay swelling instrument, inject the above leaching agent into the instrument, and determine the swelling rate of the ore sample after 8.0 h. The result is 1.840%.

[0060] Comparative Example 1

[0061] This example provides a method for enhancing the leaching of weathered crust eluvial rare earth ore. The leaching agent is the traditional ammonium salt in the industrial production of weathered crust eluvial rare earth ore, and the ammonium sulfate solution with a concentration of 0.10 mol / L is used as the leaching agent.

[0062] Specifically, it includes the following steps:

[0063] Weigh 250.0 g of the weathered crust eluvial rare earth ore sample after drying by the quartering method and place it in a glass exchange column. The average grade of rare earth in the ore sample is 0.114%. Inject the leaching agent according to a liquid-solid ratio of 2:1 (mL:g), and conduct column leaching on the weathered crust eluvial rare earth ore, and obtain and collect the rare earth leaching solution.

[0064] After the leaching is completed, calculate that the rare earth leaching rate is 84.38%, the impurity aluminum leaching rate is 82.51%, and the rare earth content in the leaching solution is 959.29 μg / g (LREEs = 627.28 μg / g, M&HREEs = 332.01 μg / g).

[0065] Determine the swelling rate of clay minerals:

[0066] Weigh 2.0 g of the ore sample after vacuum drying, keep the pressure at 8.0 MPa, press the sample on a tablet press for 5.0 min, measure the sample length with a vernier caliper, install the sample on an intelligent clay swelling instrument, inject the above leaching agent into the instrument, and determine the swelling rate of the ore sample after 8.0 h. The swelling rate of clay minerals is 2.540%.

[0067] Comparative Example 2

[0068] This example provides a method for enhanced leaching of weathered crust eluvial rare earth ore. The leaching agent is the traditional ammonium salt in the industrial production of weathered crust eluvial rare earth ore, and the ammonium chloride solution with a concentration of 0.15 mol / L is used as the leaching agent.

[0069] Specifically, it includes the following steps:

[0070] Weigh 250.0 g of the dried weathered crust eluvial rare earth ore sample by the quartering method and place it in a glass exchange column. The average rare earth grade of the ore sample is 0.114%. Inject the leaching agent according to the liquid-solid ratio of 2:1 (mL:g) to conduct column leaching on the weathered crust eluvial rare earth ore, and obtain and collect the rare earth leaching solution.

[0071] After the leaching is completed, calculate that the rare earth leaching rate is 85.67%, the impurity aluminum leaching rate is 85.16%, and the rare earth content in the leaching solution is 973.96 μg / g (LREEs = 636.87 μg / g, M&HREEs = 337.09 μg / g).

[0072] Determine the swelling rate of clay minerals:

[0073] Weigh 2.0 g of the ore sample after vacuum drying, keep the pressure at 8.0 MPa, press the sample on a tablet press for 5.0 min, measure the sample length with a vernier caliper, install the sample on an intelligent clay dilatometer, inject the above leaching agent into the instrument, and determine the swelling rate of the ore sample after 8.0 h. The swelling rate of clay minerals is 2.540%.

[0074] Data analysis

[0075] It can be seen from Examples 1 - 5 and Comparative Examples 1 - 2 that compared with the traditional ammonium salt leaching agent, the rare earth leaching rate of the weathered crust eluvial rare earth ore leaching agent of the present invention has increased by 2.00% - 3.73%, the leaching of medium and heavy rare earths has been strengthened, the heavy rare earth content in the leaching solution has increased by 14.53 - 36.26 μg / g, and at the same time, the leaching of impurity aluminum and the swelling of clay minerals have been effectively inhibited. The leaching rate of impurity aluminum in the leaching solution has decreased by 42.57% - 49.70%, and the swelling rate of clay minerals has decreased by 0.501% - 1.262%. In summary, the leaching agent for weathered crust eluvial rare earth ore of the present invention is beneficial to enhancing the leaching of rare earth ions in weathered crust eluvial rare earth ore.

[0076] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A leaching agent for weathering crust elution type rare earth ore, characterized in that: include: Monocarboxylate and water, wherein the concentration of the monocarboxylate is 0.05-0.3 mol / L.

2. A leaching agent for weathering crust elution type rare earth ore according to claim 1, characterized in that: The monocarboxylate is any one of potassium monocarboxylate, magnesium monocarboxylate, calcium monocarboxylate and ferrous monocarboxylate, or a combination of several of them.

3. A leaching agent for weathering crust elution type rare earth ore according to claim 1, characterized in that: The general formula of monocarboxylate is R1R2B, wherein R1 is a hydrocarbon carbon chain having 0, 1, or 2 carbon atoms, R2 is a carboxyl functional group, and B is a metal cation.

4. A method for preparing a leaching agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, uniformly mixing a C1-C3 monocarboxylic acid and a metal hydroxide to obtain a mixture; S2, heating the mixture obtained in S1 to 80-100° C., stirring and reacting for 3-5 hours to obtain a monocarboxylate; S3, the monocarboxylate obtained in S2 is mixed with water in proportion to obtain the leaching agent.

5. The preparation method according to claim 4, characterized in that: In S1, the C1-C3 monocarboxylic acid and the metal hydroxide are mixed in a mass ratio of 1:1-1.

5.

6. A method for enhanced leaching of weathering crust elution type rare earth ore, using the leaching agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: The weathering crust elution type rare earth ore is dried and placed in a leaching device, the leaching agent is added according to a liquid-solid ratio of 2:1 (mL:g), and a pH adjuster is added to adjust the pH value to 3.0-8.0, and leaching begins.

7. The method for enhanced leaching of weathering crust elution type rare earth ore according to claim 6, characterized in that: The pH adjuster is any one of hydrochloric acid, sulfuric acid or glacial acetic acid.