Jet-propelled electrolytic cell device and method for preparing rare earth compound through continuous electrotransformation

Abstract

The invention relates to a jet-propelled electrolytic cell device and method for preparing a rare earth compound through continuous electrotransformation, and belongs to the field of rare earth compound preparation. The jet-propelled electrolytic cell device comprises an anode chamber, a cathode chamber, a cation exchange membrane, a jet device and a direct-current power supply device, a cell body is divided into the anode chamber and the cathode chamber by the cation exchange membrane, the anode chamber is connected with a positive electrode of a direct-current power supply, the cathode chamber is connected with a negative electrode of the direct-current power supply, and the cathode chamber and the anode chamber are of an asymmetric structure. The gas spraying device comprises a gas spraying opening and a gas distribution plate, the gas spraying opening is located in the center of the bottom of the cathode chamber, the gas distribution plate is arranged on the upper portion of the gas spraying opening, the gas distribution plate reduces the diameter of bubbles entering the cathode chamber, micronization of the bubbles is achieved, and no extra stirring device needs to be added; compared with an existing electrolytic bath device, the electrolysis energy consumption for preparing the rare earth compound in unit yield is lower, and the utilization efficiency of reaction gas is higher.

Description

Technical Field

[0001] The invention belongs to the field of rare earth compound preparation, and in particular relates to a jet-type electrolytic cell device and method for preparing rare earth compounds by continuous electrical conversion. Background Art

[0002] With the rapid development of science and technology, the application of rare earth elements is becoming more and more extensive. Rare earths are important materials for manufacturing electric vehicle batteries, especially lanthanum, cerium, praseodymium, neodymium and other lanthanide elements, which play a key role in improving battery performance and extending battery life. Rare earth permanent magnet materials have high magnetic energy product and excellent corrosion resistance, and are widely used in the manufacture of wind turbines to improve power generation efficiency and reliability. Rare earth elements also play an important role in electronic display screens, optical fiber communications, magnetic recording materials, etc., and are the cornerstone of modern information technology. Rare earth materials are also widely used in defense fields such as missile guidance, radar systems, aerospace, etc., and are key materials for improving the performance of defense equipment.

[0003] Rare earth carbonate is an important compound of rare earth elements. The application number is CN202311578799.8, which proposes a device for preparing rare earth compounds by continuous electroconversion of rare earth chlorides and its application. Through the design of the continuous electroconversion device, the saturated rare earth chloride solution is electroconverted in one step to prepare rare earth hydroxides, oxides or rare earth carbonates. This invention uses rare earth chloride solution as a raw material to prepare rare earth compound materials in one step. The entire process realizes the circulation of aqueous solution, no waste liquid discharge, no additional precipitant, and eliminates the repeated consumption of acid and alkali and wastewater treatment and discharge problems from the source, realizing the short-process preparation of high-quality rare earth compounds and the recycling of raw materials. However, the electrolysis process of this invention patent does not involve the utilization efficiency of the reaction gas introduced and the energy consumption of the electrolytic cell.

[0004] Application No. CN201710324342.2 discloses a method for preparing rare earth oxide by electroconversion of rare earth chloride, which belongs to the field of hydrometallurgy of rare earth. The method pre-deacidifies the rare earth chloride solution and electrolyzes it, and the hydrochloric acid returns to the rare earth production system; the rare earth chloride solution after pre-deacidification is used as an electrolyte for electrolysis, 10℃≤temperature≤100℃, the electrolysis voltage ≥2.2V, and high-purity carbon dioxide gas is introduced into the cathode area during the electrolysis process, and stirred to directly obtain rare earth carbonate; in the cathode chamber, the electrolyte and rare earth carbonate flow in a directional manner, and solid-liquid separation is performed through a filtering device to obtain a filtrate and rare earth carbonate, and the filtrate is circulated back to the cathode chamber; the rare earth carbonate is dried and roasted to obtain carbon dioxide gas and rare earth oxide products. The invention utilizes the electrolysis process, has a simple process and low cost, and the hydrochloric acid prepared by recovering the by-products hydrogen and chlorine can be returned to the rare earth production system, and eliminates the pollution of some wastewater such as ammonia nitrogen, and finally obtains a high-purity rare earth oxide product. However, this invention patent does not involve the utilization efficiency of the introduced reaction gas and the energy consumption of the electrolytic cell.

[0005] The above-mentioned existing inventions utilize the electrolysis process to prepare high-purity rare earth oxide products and eliminate the pollution of some wastewater such as ammonia nitrogen; however, none of them take into account the utilization efficiency of the reaction gas in the preparation process of rare earth compounds. The low utilization efficiency of the reaction gas not only increases the consumption of the reaction gas, but also causes the purity of the hydrogen produced by the cathode to be low, making subsequent separation difficult. Summary of the invention

[0006] In view of the problems in the prior art, the purpose of the present invention is to provide a jet electrolytic cell device and method for preparing rare earth compounds through continuous electroconversion. The electrolytic cell comprises an anode chamber, a cathode chamber, a cation exchange membrane, a jet device and a DC power supply device, wherein the anode chamber and the cathode chamber adopt an asymmetric structure, the cathode chamber is provided with a jet device, the jet port of which is located at the bottom center of the cathode chamber, and a gas distribution plate is provided on the upper part of the jet port, which can reduce the bubble diameter of the reaction gas entering the cathode chamber, realize the miniaturization of the bubbles, and thus significantly improve the electrolytic energy consumption and the utilization efficiency of the reaction gas in preparing rare earth compounds through electroconversion of rare earth chloride solution.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a jet-type electrolytic cell device for preparing rare earth compounds through continuous electroconversion, comprising: an anode chamber, a cathode chamber, a cation exchange membrane, a jet device and a DC power supply device, wherein the cation exchange membrane divides the cell body into an anode chamber and a cathode chamber, the anode chamber is connected to the positive electrode of the DC power supply, the cathode chamber is connected to the negative electrode of the DC power supply, and the cathode chamber and the anode chamber adopt an asymmetric structure;

[0009] The gas injection device comprises a gas injection port and a gas distribution plate. The gas injection port is located at the bottom center of the cathode chamber, and a gas distribution plate is arranged on the upper part of the gas injection port.

[0010] Furthermore, the gas distribution plate is provided with evenly distributed ventilation holes, and the aperture of the ventilation holes is ≤74 μm.

[0011] Furthermore, the size of the cathode chamber is 2-5 times the size of the anode chamber.

[0012] Furthermore, the anode plate and the cation exchange membrane in the anode chamber are tightly fitted by a flexible spring press mesh.

[0013] Furthermore, the anode chamber is provided with an anode liquid inlet at the lower part and an anode liquid outlet at the upper part;

[0014] The cathode chamber is provided with a cathode liquid inlet at the lower part and a cathode liquid outlet at the upper part. The product rare earth compound precipitate is sent out of the electrolytic cell through the cathode liquid outlet to realize continuous production.

[0015] Furthermore, the anode chamber electrode plate is a grid-shaped titanium plate, and the surface is coated with ruthenium oxide-iridium;

[0016] The cathode chamber electrode plate is a grid-shaped nickel plate with a ruthenium oxide coating on the surface.

[0017] The present invention also provides a method for preparing rare earth compounds by continuous electroconversion using the jet electrolyzer device, comprising the following steps:

[0018] Step 1: A rare earth chloride aqueous solution is introduced into the anode chamber, and a sodium chloride solution is introduced into the cathode chamber;

[0019] Step 2: The reaction gas is introduced through the jet port of the jet device at the bottom of the cathode chamber, and the reaction gas is dispersed through the vent holes of the gas distribution plate to form micro-bubbles;

[0020] Step 3: Turn on the DC power supply device and adjust the current density. The micronized reaction gas bubbles in step 2 react with the rare earth cations that pass through the cation exchange membrane and enter the cathode chamber to directly produce rare earth compounds.

[0021] Step 4: After the electrolysis is completed, turn off the DC power supply, take out the residual electrolyte in the anode chamber and cathode chamber of the electrolytic cell, and close the jet outlet of the jet device.

[0022] The vent holes of the gas distribution plate break up the reaction gas to form micronized reaction gas bubbles, which react with the rare earth ions that enter the cathode chamber through the cation exchange membrane to prepare rare earth compound precipitates. Due to the effect of the micronized bubbles, the product rare earth compound precipitates are in a fluidized bed state, which is easy to be discharged through the liquid outlet of the cathode chamber, and the reaction gas utilization efficiency is improved.

[0023] Furthermore, the rare earth chloride aqueous solution in step 1, wherein the mass concentration of the rare earth chloride component is 100g / L-500g / L;

[0024] The sodium chloride solution described in step 1, wherein the mass concentration of the sodium chloride component is 20g / L-200g / L.

[0025] Furthermore, the reaction gas flow rate in step 2 is 50 mL / min-500 mL / min.

[0026] Furthermore, the current density in step 3 is 300A / m 2 -1000A / m 2 .

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) In the present invention, the anode chamber and the cathode chamber adopt an asymmetric structure. The cathode chamber is provided with a gas injection device. The gas inlet (gas injection port) is located at the bottom of the cathode chamber. A gas distribution plate is provided on the upper part of the gas outlet to reduce the diameter of the gas bubbles entering the cathode chamber and achieve bubble miniaturization. No additional stirring device is required. Compared with an electrolytic cell without a gas distribution plate, when preparing rare earth compounds as rare earth carbonate, the utilization efficiency of carbon dioxide is increased by nearly 60%.

[0029] (2) The present invention uses an anode chamber electrode plate and a cation exchange membrane in close contact with a flexible spring net at the anode. Compared with the prior art, when preparing a unit output of rare earth compounds as rare earth carbonate, the present invention reduces the electrolysis energy consumption by more than 60%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic structural diagram of a jet-type electrolytic cell device for preparing rare earth compounds through continuous electroconversion according to the present invention;

[0031] Among them: 1-anode liquid inlet; 2-anode liquid outlet; 3: cathode liquid inlet; 4-cathode liquid outlet; 5-air jet; 6-anode plate; 7-cation exchange membrane; 8-cathode plate; 9-gas distribution plate; 10-flexible spring pressure net; 11-vent; 12-anode chamber; 13-cathode chamber.

[0032] Figure 2 This is an exploded view of a jet-type electrolytic cell device for preparing rare earth compounds by continuous electrical conversion according to the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] Example 1

[0035] A jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion, such as Figure 1 As shown, it includes an anode chamber 12, a cathode chamber 13, an ion exchange membrane 7, an air jet 5, and a gas distribution plate 9. The lower part of the anode chamber 12 is provided with an anode liquid inlet 1, and the upper part is provided with an anode liquid outlet 2. The lower part of the cathode chamber 13 is provided with a cathode liquid inlet 3, and the upper part is provided with a cathode liquid outlet 4. The center of the bottom of the cathode chamber 13 is provided with an air jet 5, and the upper part of the air jet 5 is provided with a gas distribution plate 9. The anode plate 6 is a grid-shaped titanium plate with a ruthenium oxide-iridium coating on the surface. The anode plate 6 is tightly fitted with the cation exchange membrane 7 by a flexible spring pressing net 10. The cathode plate 8 is a grid-shaped nickel plate with a ruthenium oxide coating on the surface. The distance between the cathode plate 8 and the cation exchange membrane 7 is 1mm-5mm; as shown Figure 2As shown, the gas distribution plate 9 is provided with evenly distributed ventilation holes 11 .

[0036] Example 2

[0037] The method of using the jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion in Example 1 to prepare rare earth compounds, wherein the aperture of the vent hole 11 of the jet electrolytic cell device is 74 μm, the size of the cathode chamber is 5 times the size of the anode chamber, the rare earth compound is rare earth carbonate, and the reaction gas is high-purity carbon dioxide gas, comprises the following steps:

[0038] Step 1: The electrode plate in the anode chamber is tightly fitted to the cation exchange membrane using a flexible spring net, and the distance between the electrode plate in the cathode chamber and the cation exchange membrane is 1.5 mm; 300 g / L rare earth chloride solution is passed into the anode chamber, and 120 g / L sodium chloride solution is passed into the cathode chamber;

[0039] Step 2: Open the air jet at the bottom of the cathode chamber and introduce high-purity carbon dioxide gas at a rate of 200 mL / min. The gas is dispersed through the air holes of the gas distribution plate to form micronized carbon dioxide bubbles.

[0040] Step 3: Turn on the DC power supply and adjust the current density to 800A / m 2 In step 2, the micronized carbon dioxide bubbles react with the rare earth cations that enter the cathode chamber through the cation exchange membrane, and are carbonized and electrolyzed to prepare rare earth carbonate precipitates;

[0041] Step 4: After the electrolysis is completed, turn off the DC power supply, take out the residual electrolyte in the anode chamber and cathode chamber of the electrolytic cell, and close the air jet at the bottom of the cathode chamber.

[0042] Example 3

[0043] The method of using the jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion in Example 1 to prepare rare earth compounds, wherein the diameter of the vent hole 11 of the jet electrolytic cell device is 44 μm, the size of the cathode chamber is 4 times the size of the anode chamber, the rare earth compound is rare earth carbonate, and the reaction gas is high-purity carbon dioxide gas, comprises the following steps:

[0044] Step 1: The electrode plate in the anode chamber is tightly fitted to the cation exchange membrane using a flexible spring net, and the distance between the electrode plate in the cathode chamber and the cation exchange membrane is 2 mm; 300 g / L rare earth chloride solution is passed into the anode chamber, and 100 g / L sodium chloride solution is passed into the cathode chamber;

[0045] Step 2: Open the air jet at the bottom of the cathode chamber and introduce high-purity carbon dioxide gas at a rate of 200 mL / min. The gas is dispersed through the air holes of the gas distribution plate to form micronized carbon dioxide bubbles.

[0046] Step 3: Turn on the DC power supply and adjust the current density to 500A / m 2 , carbonization electrolysis to prepare rare earth carbonate precipitate;

[0047] Step 4: After the electrolysis is completed, turn off the DC power supply, take out the residual electrolyte in the anode chamber and cathode chamber of the electrolytic cell, and close the air jet at the bottom of the cathode chamber.

[0048] Example 4

[0049] The method for preparing rare earth compounds by using the jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion in Example 1, wherein the aperture of the vent hole 11 of the jet electrolytic cell device is 37 μm, the size of the cathode chamber is 3 times the size of the anode chamber, the rare earth compound is rare earth carbonate, and the reaction gas is high-purity carbon dioxide gas, comprises the following steps:

[0050] Step 1: The electrode plate in the anode chamber is tightly fitted to the cation exchange membrane using a flexible spring net, and the distance between the electrode plate in the cathode chamber and the cation exchange membrane is 1 mm; 100 g / L rare earth chloride solution is passed into the anode chamber, and 20 g / L sodium chloride solution is passed into the cathode chamber;

[0051] Step 2: Open the air jet at the bottom of the cathode chamber and introduce high-purity carbon dioxide gas at a rate of 50 mL / min. The gas is dispersed by the vent holes of the gas distribution plate to form micronized carbon dioxide bubbles;

[0052] Step 3: Turn on the DC power supply and adjust the current density to 300A / m 2 , carbonization electrolysis to prepare rare earth carbonate precipitate;

[0053] Step 4: After the electrolysis is completed, turn off the DC power supply, take out the residual electrolyte in the anode chamber and cathode chamber of the electrolytic cell, and close the air jet at the bottom of the cathode chamber.

[0054] Example 5

[0055] The method for preparing rare earth compounds by using the jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion in Example 1, wherein the aperture of the vent hole 11 of the jet electrolytic cell device is 20 μm, the size of the cathode chamber is twice the size of the anode chamber, the rare earth compound is rare earth carbonate, and the reaction gas is high-purity carbon dioxide gas, comprises the following steps:

[0056] Step 1: The electrode plate in the anode chamber is tightly fitted to the cation exchange membrane using a flexible spring net, and the distance between the electrode plate in the cathode chamber and the cation exchange membrane is 5 mm; 500 g / L rare earth chloride solution is passed into the anode chamber, and 200 g / L sodium chloride solution is passed into the cathode chamber;

[0057] Step 2: Open the vent hole of the fluidized bed type gas distribution device installed at the bottom of the cathode chamber, and introduce high-purity carbon dioxide gas at a rate of 500 mL / min;

[0058] Step 3: Turn on the DC power supply and adjust the current density to 1000A / m 2 , carbonization electrolysis to prepare rare earth carbonate precipitate;

[0059] Step 4: After the electrolysis is completed, turn off the DC power supply, take out the residual electrolyte in the anode chamber and cathode chamber of the electrolytic cell, and close the air jet at the bottom of the cathode chamber.

[0060] Comparative Example 1

[0061] The method of preparing a rare earth compound by electrolysis in an existing conventional electrolytic cell, wherein the rare earth compound is also rare earth carbonate, and introducing high-purity carbon dioxide gas, comprises the following steps:

[0062] Step 1: The distance between the electrode plate in the anode chamber and the cation exchange membrane is 20 mm, and the distance between the electrode plate in the cathode chamber and the cation exchange membrane is 20 mm. The anode chamber contains 130 g / L rare earth chloride solution, and the cathode chamber contains 30 g / L sodium chloride solution;

[0063] Step 2: Open the cathode chamber gas inlet and introduce carbon dioxide gas at a rate of 1000 mL / min;

[0064] Step 3: Turn on the DC power supply, current density 100A / m 2 , to carry out carbonization electrolysis;

[0065] Step 4: After the electrolysis is completed, turn off the DC power supply, take out the residual electrolyte in the anode chamber and cathode chamber of the electrolytic cell, and close the air inlet of the cathode chamber.

[0066] Comparative Example 2

[0067] The method for preparing rare earth carbonate is the same as that in Example 5, except that the jet electrolytic cell apparatus for preparing rare earth compounds through continuous electroconversion is not provided with a gas distribution plate.

[0068] Energy consumption analysis

[0069] The formula for calculating the electrolysis energy consumption per kilogram of rare earth compound is as follows:

[0070] Unit energy consumption (KWh / kg) = voltage (V) × current (A) × time (h) / unit time output (kg)

[0071] The energy consumption of the rare earth carbonate electrolytic cell per unit time and per unit output of Examples 2-5 and Comparative Examples 1-2 is shown in Table 1.

[0072] Table 1 Energy consumption of rare earth carbonate electrolyzer per unit time and unit output

[0073]

[0074] The calculation formula for carbon dioxide utilization efficiency is as follows:

[0075] Carbon dioxide utilization efficiency (%) = actual carbon dioxide consumption per unit time (mL) / carbon dioxide introduced per unit time (mL) The carbon dioxide utilization efficiency of Examples 2-5 and Comparative Examples 1-2 is shown in Table 2.

[0076] Table 2 Carbon dioxide utilization efficiency per unit time and unit output of rare earth carbonate electrolyzer

[0077]

[0078] As shown in Tables 1 and 2, the method for preparing rare earth compounds by using the jet electrolyzer device and continuous electro-conversion in Examples 2-5, compared with the prior art comparative example 1, the electrolysis energy consumption per kilogram of rare earth carbonate is reduced by 70.6%, 74.0%, 60.6% and 74.5%, respectively, and the carbon dioxide utilization efficiency is increased by more than 21 times, indicating that the jet electrolyzer device for preparing rare earth compounds by continuous electro-conversion of the present invention has significantly improved the reaction gas utilization efficiency when preparing rare earth carbonate; the carbon dioxide utilization efficiency of Example 5 is improved by nearly 60% compared with that of Comparative Example 2, indicating that the gas distribution plate plays a significant role in improving the reaction gas utilization efficiency.

Claims

1. A jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion, characterized in that: include: A cathode chamber, a cation exchange membrane, an air jet device and a DC power supply device, wherein the cation exchange membrane divides the tank into an anode chamber and a cathode chamber, the anode chamber is connected to the positive electrode of the DC power supply, the cathode chamber is connected to the negative electrode of the DC power supply, and the cathode chamber and the anode chamber adopt an asymmetric structure; The gas injection device comprises a gas injection port and a gas distribution plate. The gas injection port is located at the bottom center of the cathode chamber, and a gas distribution plate is arranged on the upper part of the gas injection port.

2. The jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion according to claim 1, characterized in that: The gas distribution plate is provided with evenly distributed ventilation holes, and the aperture of the ventilation holes is ≤74 μm.

3. The jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion according to claim 1, characterized in that: The size of the cathode chamber is 2-5 times the size of the anode chamber.

4. The jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion according to claim 1, characterized in that: The anode plate and the cation exchange membrane in the anode chamber are tightly fitted by using a flexible spring press net.

5. The jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion according to claim 1, characterized in that: The anode chamber is provided with an anode liquid inlet at the lower part and an anode liquid outlet at the upper part; The cathode chamber is provided with a cathode liquid inlet at the lower part and a cathode liquid outlet at the upper part. The product rare earth compound precipitate is sent out of the electrolytic cell through the cathode liquid outlet to realize continuous production.

6. The jet electrolytic cell device for preparing rare earth compounds by continuous electroconversion according to claim 1, characterized in that: The anode chamber electrode plate is a grid-shaped titanium plate with a ruthenium oxide-iridium coating on the surface; The cathode chamber electrode plate is a grid-shaped nickel plate with a ruthenium oxide coating on the surface.

7. A method for preparing rare earth compounds by continuous electrolysis using the jet electrolyzer device for preparing rare earth compounds by continuous electrolysis according to claim 1, characterized in that: The following steps are involved: Step 1: A rare earth chloride aqueous solution is introduced into the anode chamber, and a sodium chloride solution is introduced into the cathode chamber; Step 2: The reaction gas is introduced through the jet port of the jet device at the bottom of the cathode chamber, and the reaction gas is dispersed through the vent holes of the gas distribution plate to form micro-bubbles; Step 3: Turn on the DC power supply device and adjust the current density. The micronized reaction gas bubbles in step 2 react with the rare earth cations that pass through the cation exchange membrane and enter the cathode chamber to directly produce rare earth compounds. Step 4: After the electrolysis is completed, turn off the DC power supply, take out the residual electrolyte in the anode chamber and cathode chamber of the electrolytic cell, and close the jet outlet of the jet device.

8. The method for preparing rare earth compounds by continuous electroconversion according to claim 7, characterized in that: The rare earth chloride aqueous solution in step 1, wherein the mass concentration of the rare earth chloride component is 100g / L-500g / L; the sodium chloride solution in step 1, wherein the mass concentration of the sodium chloride component is 20g / L-200g / L.

9. The method for preparing rare earth compounds by continuous electroconversion according to claim 7, characterized in that: The reaction gas flow rate in step 2 is 50 mL / min-500 mL / min.

10. The method for preparing rare earth compounds by continuous electroconversion according to claim 7, characterized in that: The current density in step 3 is 300A / m 2 -1000A / m 2 .

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