Method for improving ion type rare earth leaching rate

Abstract

The application discloses a method for improving ion type rare earth leaching rate, and belongs to the technical field of rare earth leaching. The ore-bearing layer and non-ore layer of ion type rare earth ore body are sampled, the thicknesses of the ore-bearing layer and the non-ore layer are respectively determined, and the grade of ion type rare earth in the ore-bearing layer is determined; according to the thickness ratio of the ore-bearing layer and the non-ore layer, the non-ore layer soil and the ore-bearing layer soil are sequentially loaded in a leaching column, a simulation leaching column is constructed, and desorption test is carried out to determine the desorption effect of the non-ore layer on rare earth ions; according to the desorption test result and the reserves of ion type rare earth in the ore body, the amount of leaching agent is determined, the leaching agent is adjusted into ore leaching liquid, and then the ore leaching liquid is injected into the ore body; top pressure water is injected into the ore body, and leaching mother liquor is collected; the thickness ratio of the non-ore layer and the ore-bearing layer is accurately determined, the desorption effect is determined by relying on the simulation leaching column, and the amount of leaching agent and the concentration of top pressure water are optimized, so that the rare earth leaching rate is stabilized at 99%-99.7%, which is significantly improved compared with the traditional process.

Description

Technical Field

[0001] This invention relates to the field of rare earth leaching technology, and in particular to a method for improving the leaching rate of ion-type rare earths. Background Technology

[0002] Ion-adsorption rare earth deposits, as the core source of medium and heavy rare earth elements globally, are an important component of my country's strategic mineral resources. Their efficient development and utilization are crucial for ensuring the security of the national rare earth industry chain. In these deposits, rare earth elements are mainly adsorbed in ionic form on the surface of clay minerals such as kaolinite and montmorillonite. Industrially, in-situ leaching is commonly used for mining. This involves injecting leaching agents, primarily ammonium sulfate and magnesium sulfate, through injection holes at the mountain top. The rare earth ions on the surface of the clay minerals are desorbed into the solution using the principle of ion exchange. Gravity then causes the rare earth-containing leachate to migrate towards the bottom of the mountain. Finally, the rare earth mother liquor is collected through guide holes, providing raw materials for subsequent rare earth separation and purification.

[0003] However, existing in-situ leaching processes have certain shortcomings: Along the migration path from the rare earth ore body to the diversion holes at the bottom of the mountain, there are generally non-ore layers of varying thickness (mainly composed of clay, sandy clay, etc.). When the leachate containing rare earth ions flows through these non-ore layers, the clay minerals in the non-ore layers exert a reverse adsorption effect on the rare earth ions, causing some rare earth ions to be retained in the non-ore layers and unable to enter the collection system. Furthermore, current traditional processes completely disregard the reverse adsorption effect of non-ore layers, consistently using a fixed ratio (usually 8 times the total rare earth reserves of the ore body) of leaching agent dosage without optimizing process parameters for differences in non-ore layer thickness. This may directly result in a consistently low rare earth leaching rate. As the thickness of the non-ore layer increases, the reverse adsorption effect further intensifies, with leaching rates in some mining areas even falling below 80%. This not only causes a serious waste of rare earth resources but also increases mining costs and environmental governance pressure due to low leaching efficiency, hindering the green and efficient development of ion-adsorption rare earth mines. Summary of the Invention

[0004] The purpose of this invention is to solve the problems mentioned in the background art by proposing a method to improve the leaching rate of ion-type rare earth elements.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for improving the leaching rate of ion-type rare earth elements, comprising the following steps:

[0007] Step 1: Sample the ore-bearing and non-ore-bearing layers of the ion-adsorption rare earth ore body, measure the thickness of the ore-bearing and non-ore-bearing layers respectively, and determine the grade of ion-adsorption rare earth in the ore-bearing layer.

[0008] Step 2: Based on the thickness ratio of the ore-bearing layer to the non-ore-bearing layer determined in Step 1, non-ore-bearing layer soil and ore-bearing layer soil are sequentially loaded into the leaching column to construct a simulated leaching column, and a reverse adsorption test is conducted to determine the reverse adsorption effect of the non-ore-bearing layer on rare earth ions.

[0009] Step 3: Based on the results of the reverse adsorption test in Step 2 and the reserves of ionic rare earth elements in the ore body, determine the amount of leaching agent to be used, and then inject the leaching agent into the ore body after preparing the leaching solution.

[0010] Step 4: Inject top water into the ore body and collect the leaching mother liquor. When the concentration of ionic rare earth elements in the leaching mother liquor is lower than 0.1 g / L, stop injecting top water.

[0011] Preferably, the mineralized layer is a mineralized layer with an ionic rare earth content ≥ 0.02%, and the non-mineralized layer is a mineralized layer with an ionic rare earth content < 0.02%.

[0012] Furthermore, the leaching agent is ammonium sulfate or magnesium sulfate, and the mass concentration of the leaching agent in the leaching solution is 2%.

[0013] Furthermore, the capping water contains an extractant with a mass concentration of 0.3% to 0.7%.

[0014] Furthermore, based on the measured thickness ratio of the ore-bearing layer to the non-ore-bearing layer, the proportional relationship between the amount of leaching agent and the reserves of ion-adsorption rare earth elements in the ore body is determined.

[0015] Furthermore, when the ratio of the thickness of the non-ore layer to the thickness of the ore layer is 0.1 to 0.2, the ratio of the amount of leaching agent to the ion-adsorption rare earth reserves in the ore body is 1:8.6 to 1:9.5.

[0016] Furthermore, when the ratio of the thickness of the non-ore layer to the thickness of the ore layer is 0.2 to 0.4, the ratio of the amount of leaching agent to the ion-adsorption rare earth reserves in the ore body is 1:8.8 to 1:10.

[0017] Furthermore, when the ratio of the thickness of the non-ore layer to the thickness of the ore layer is 0.4 to 0.6, the ratio of the amount of leaching agent to the ion-adsorption rare earth reserves in the ore body is 1:9 to 1:10.6.

[0018] Furthermore, when the ratio of the thickness of the non-ore layer to the thickness of the ore layer is 0.6 to 0.8, the ratio of the amount of leaching agent to the ion-adsorption rare earth reserves in the ore body is 1:9.4 to 1:11.

[0019] Furthermore, when the ratio of the thickness of the non-ore layer to the thickness of the ore layer is 0.8 to 1.0, the ratio of the amount of leaching agent to the ion-adsorption rare earth reserves in the ore body is 1:9.8 to 1:12.

[0020] Compared with existing technologies, this invention provides a method to improve the leaching rate of ion-type rare earth elements, which has the following beneficial effects: This invention incorporates the reverse adsorption effect of the ore-free layer into the leaching process optimization system: First, the thickness ratio of the ore-bearing layer to the ore-free layer is determined through exploration. Then, the reverse adsorption characteristics of the ore-free layer are measured based on the simulated leaching column. Finally, the dosage of leaching agent and the concentration of top water are matched in a targeted manner. The rare earth leaching rate of this invention is stable, and the leaching rate is significantly improved compared with the traditional process. It effectively solves the problem of rare earth loss caused by reverse adsorption of the ore-free layer, greatly improves resource utilization, and reduces the waste of mineral resources.

[0021] This invention achieves customized leaching of ion-adsorption rare earth ores under different geological conditions. This avoids the inability to desorb reverse-adsorbed rare earths due to insufficient leaching agent in traditional processes, and also prevents cost waste and environmental pollution caused by excessive leaching agent, thus effectively improving the adaptability and economy of the process. Attached Figure Description

[0022] Figure 1 This is a flowchart of a method for improving the leaching rate of ion-type rare earth elements proposed in this invention;

[0023] Figure 2 This is a comparison chart of the leaching rates of the embodiments and comparative examples of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] Example 1: Refer to Figure 1 A method for improving the leaching rate of ion-type rare earth elements includes the following steps:

[0026] Step 1: Exploration and sampling of the ion-adsorption rare earth ore body to determine that the thickness of the ore-bearing layer is 15 meters and the rare earth grade is 0.05%; the thickness of the non-ore-bearing layer is 1.5 meters; the calculated ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.1.

[0027] Step 2: Based on the thickness ratio determined in Step 1, fill a laboratory leaching column with a 5cm (1000g) high layer of mineral-free soil and a 50cm (5100g) high layer of mineralized soil to construct a simulated leaching column. Conduct a reverse adsorption experiment to determine the reverse adsorption effect of the mineral-free layer on rare earth ions.

[0028] Step 3: Add 1100 mL of 2% ammonium sulfate solution and 3000 mL of 0.3% ammonium sulfate solution to the leaching column of Step B sequentially via a peristaltic pump.

[0029] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0030] In practice, calculations show that the rare earth leaching rate in this embodiment reaches 99.6%.

[0031] Example 2: Refer to Figure 1 A method for improving the leaching rate of ion-type rare earth elements includes the following steps:

[0032] Step 1: Exploration and determination show that the thickness of the ore-bearing layer is 12 meters, with a rare earth grade of 0.04%; the thickness of the non-ore-bearing layer is 4.8 meters; and the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.4.

[0033] Step 2: Add mineral-free soil (1000g) to a height of 20cm and mineralized soil (5100g) to a height of 50cm into the leaching column in sequence.

[0034] Step 3: Add 1020 mL of 2% ammonium sulfate solution and 3000 mL of 0.3% ammonium sulfate solution to the leaching column of Step B sequentially via a peristaltic pump.

[0035] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0036] In practice, calculations show that the rare earth leaching rate in this embodiment reaches 99.7%.

[0037] Example 3: Reference Figure 1 A method for improving the leaching rate of ion-type rare earth elements includes the following steps:

[0038] Step 1: Exploration and determination show that the thickness of the ore-bearing layer is 10 meters and the rare earth grade is 0.05%; the thickness of the non-ore-bearing layer is 6 meters, and the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.6.

[0039] Step 2: Add mineral-free soil (1000g) to a height of 30cm and mineralized soil (5100g) to a height of 50cm into the leaching column in sequence.

[0040] Step 3: Add 1350 mL of 2% ammonium sulfate solution and 3000 mL of 0.3% ammonium sulfate solution to the leaching column of Step B sequentially via a peristaltic pump.

[0041] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0042] In practice, calculations show that the rare earth leaching rate in this embodiment reaches 99.2%.

[0043] Example 4: Reference Figure 1A method for improving the leaching rate of ion-type rare earth elements includes the following steps:

[0044] Step 1: Exploration and determination show that the thickness of the ore-bearing layer is 8 meters and the rare earth grade is 0.03%; the thickness of the non-ore-bearing layer is 6.4 meters, and the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.8.

[0045] Step 2: Add mineral-free soil (1000g) to a height of 40cm and mineralized soil (5100g) to a height of 50cm into the leaching column in sequence.

[0046] Step 3: Add 850 mL of 2% ammonium sulfate solution and 3000 mL of 0.5% ammonium sulfate solution to the leaching column of Step B sequentially via a peristaltic pump.

[0047] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0048] In practice, calculations show that the rare earth leaching rate in this embodiment reaches 99.1%.

[0049] Example 5: Refer to Figure 1 A method for improving the leaching rate of ion-type rare earth elements includes the following steps:

[0050] Step 1: Exploration and surveying have determined that the thickness of the ore-bearing layer is 10 meters and the rare earth grade is 0.04%; the thickness of the non-ore-bearing layer is 10 meters, and the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 1.0.

[0051] Step 2: Add mineral-free soil (1000g) to a height of 50cm and mineralized soil (5100g) to a height of 50cm in sequence to the leaching column.

[0052] Step 3: Add 1230 mL of 2% ammonium sulfate solution and 3000 mL of 0.6% ammonium sulfate solution to the leaching column of Step B sequentially via a peristaltic pump.

[0053] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0054] In practice, calculations show that the rare earth leaching rate in this embodiment reaches 99%.

[0055] Comparative Example 1: A traditional ion-type rare earth leaching method, comprising the following steps:

[0056] Step 1: Exploration and sampling of the ion-adsorption rare earth ore body to determine that the thickness of the ore-bearing layer is 15 meters and the rare earth grade is 0.05%; the thickness of the non-ore-bearing layer is 1.5 meters; the calculated ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.1.

[0057] Step 2: The traditional process is used directly, without constructing a simulated leaching column or measuring the reverse adsorption effect of the mineral-free layer.

[0058] Step 3: Calculate the amount of leaching agent according to the traditional fixed ratio (the amount of leaching agent is 8 times the total rare earth reserves in the ore body), and add 1020 mL of 2% ammonium sulfate solution and 3000 mL of 0% ammonium sulfate solution to the leaching system corresponding to the ore body conditions in sequence via peristaltic pump.

[0059] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0060] In practice, calculations show that the rare earth leaching rate in this comparative example is only 94%.

[0061] Comparative Example 2: A conventional ion-type rare earth leaching method, comprising the following steps:

[0062] Step 1: Exploration and determination show that the thickness of the ore-bearing layer is 12 meters, with a rare earth grade of 0.04%; the thickness of the non-ore-bearing layer is 4.8 meters; and the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.4.

[0063] Step 2: Do not construct a simulated leaching column, do not conduct reverse adsorption experiments in the mineral-free layer, and ignore the reverse adsorption effect in the mineral-free layer.

[0064] Step 3: Determine the amount of leaching agent according to the traditional fixed ratio (the amount of leaching agent is 8 times the total rare earth reserves in the ore body). Add 820 mL of 2% ammonium sulfate solution and 3000 mL of 0.3% ammonium sulfate solution to the corresponding leaching system in sequence via peristaltic pump (the concentration of the top water in the traditional process is fixed at 0.3%, which is consistent with the initial volume of the leaching solution in Example 2).

[0065] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0066] In practice, calculations show that the rare earth leaching rate in this comparative example is only 90%.

[0067] Comparative Example 3: A traditional ion-type rare earth leaching method, comprising the following steps:

[0068] Step 1: Exploration and determination show that the thickness of the ore-bearing layer is 10 meters and the rare earth grade is 0.05%; the thickness of the non-ore-bearing layer is 6 meters, and the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.6.

[0069] Step 2: Without constructing a simulated leaching column or measuring the reverse adsorption effect, the traditional process approach is adopted, ignoring the influence of the ore-free layer.

[0070] Step 3: Calculate the dosage according to the traditional fixed ratio of 8 times the total rare earth reserves, and add 1020 mL of 2% ammonium sulfate solution and 3000 mL of 0.3% ammonium sulfate solution to the corresponding leaching system in sequence via peristaltic pump (the traditional top water concentration is fixed at 0.3%, which is consistent with the initial volume of the leaching solution in Example 3).

[0071] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0072] In practice, calculations show that the rare earth leaching rate in this comparative example is only 88%.

[0073] Comparative Example 4: A traditional ion-type rare earth leaching method, including the following steps:

[0074] Step 1: Exploration and determination show that the thickness of the ore-bearing layer is 8 meters and the rare earth grade is 0.03%; the thickness of the non-ore-bearing layer is 6.4 meters, and the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.8.

[0075] Step 2: No simulated leaching column reverse adsorption test is conducted, and the reverse adsorption effect of the mineral-free layer on rare earth ions is not considered.

[0076] Step 3: Determine the dosage according to the traditional fixed ratio (the amount of leaching agent is 8 times the total rare earth reserves), and add 615 mL of 2% ammonium sulfate solution and 3000 mL of 0.3% ammonium sulfate solution to the corresponding leaching system in sequence via peristaltic pump (the traditional top water concentration is fixed at 0.3%, which is consistent with the initial volume of leaching solution in Example 4).

[0077] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0078] In practice, calculations show that the rare earth leaching rate in this comparative example is only 84%.

[0079] Comparative Example 5: A conventional ion-type rare earth leaching method, comprising the following steps:

[0080] Step 1: Exploration and determination show that the thickness of the ore-bearing layer is 10 meters and the rare earth grade is 0.04%; the thickness of the non-ore-bearing layer is 10 meters, and the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 1.0.

[0081] Step 2: No simulated leaching column is constructed, and the reverse adsorption effect of the ore-free layer is not measured. The influence of the ore-free layer is ignored by using the traditional process.

[0082] Step 3: Calculate the dosage according to the traditional fixed ratio of 8 times the total rare earth reserves, and add 820 mL of 2% ammonium sulfate solution and 3000 mL of 0.3% ammonium sulfate solution to the corresponding leaching system in sequence via peristaltic pump (the traditional top water concentration is fixed at 0.3%, which is consistent with the initial volume of the leaching solution in Example 5).

[0083] Step 4: Collect the leachate mother liquor and calculate the volume and rare earth ion concentration.

[0084] In practice, calculations show that the rare earth leaching rate in this comparative example is only 80%.

[0085] In summary, the calculation results from Comparative Examples 1-5 and Examples 1-5 were statistically summarized and plotted. Figure 2 Through comparative analysis, this invention accurately measures the thickness ratio of the non-mineralized layer to the mineralized layer, clarifies the reverse adsorption effect based on the simulated leaching column, and optimizes the dosage of leaching agent and the concentration of top water in a targeted manner, so that the rare earth leaching rate can be stably reached 99%-99.7%, which is significantly improved compared with the traditional process (80%-94%), and effectively solves the problem of rare earth resource waste caused by reverse adsorption in the non-mineralized layer.

[0086] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for improving the leaching rate of ion-type rare earths, characterized in that, The steps are as follows: Step one, sampling the ore-bearing layer and non-ore-bearing layer of the ion-type rare earth ore body, respectively measuring the thickness of the ore-bearing layer and non-ore-bearing layer, and measuring the grade of ion-type rare earth in the ore-bearing layer; Step two, according to the thickness ratio of the ore-bearing layer and non-ore-bearing layer measured in step one, sequentially loading the non-ore-bearing layer soil and ore-bearing layer soil into the leaching column to construct a simulated leaching column, and performing desorption test to measure the desorption effect of the non-ore-bearing layer on rare earth ions; Step three, according to the desorption test results in step two and the reserves of ion-type rare earth in the ore body, determining the amount of leaching agent, and after the leaching agent is formulated into leaching solution, injecting the leaching solution into the ore body; Step four, injecting pressure water into the ore body, collecting leaching mother liquor, and stopping the injection of pressure water when the concentration of ion-type rare earth in the leaching mother liquor is less than 0.1 g / L; The ore-bearing layer is a mineral layer with ion-type rare earth content ≥0.02%, and the non-ore-bearing layer is a mineral layer with ion-type rare earth content <0.02%; The pressure water contains leaching agent with a mass concentration of 0.3% to 0.7%; According to the measured thickness ratio of the ore-bearing layer and non-ore-bearing layer, the proportion relationship between the amount of leaching agent and the reserves of ion-type rare earth in the ore body is determined.

2. The method for improving the leaching rate of ionic rare earth according to claim 1, characterized in that, The leaching agent is ammonium sulfate or magnesium sulfate, and the mass concentration of leaching agent in the leaching solution is 2%.

3. The method for improving the leaching rate of ionic rare earth according to claim 1, characterized in that, When the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.1 to 0.2, the ratio of the amount of leaching agent to the reserves of ion-type rare earth in the ore body is 1:8.6 to 1:9.

5.

4. The method for improving the leaching rate of ionic rare earth according to claim 1, characterized in that, When the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.2 to 0.4, the ratio of the amount of leaching agent to the reserves of ion-type rare earth in the ore body is 1:8.8 to 1:

10.

5. The method for improving the leaching rate of ionic rare earth according to claim 1, characterized in that, When the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.4 to 0.6, the ratio of the amount of leaching agent to the reserves of ion-type rare earth in the ore body is 1:9 to 1:10.

6.

6. The method for improving the leaching rate of ionic rare earth according to claim 1, characterized in that, When the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.6 to 0.8, the ratio of the amount of leaching agent to the reserves of ion-type rare earth in the ore body is 1:9.4 to 1:

11.

7. The method for improving the leaching rate of ionic rare earth according to claim 1, characterized in that, When the ratio of the thickness of the non-ore-bearing layer to the thickness of the ore-bearing layer is 0.8 to 1.0, the ratio of the amount of leaching agent to the reserves of ion-type rare earth in the ore body is 1:9.8 to 1:12.

Images