A jet electrolysis cell apparatus and method for the continuous electrotransformation production of rare earth compounds

Abstract

The present application relates to a kind of jet electrolytic cell device and method for preparing rare earth compound by continuous electrotransformation, belong to the field of rare earth compound preparation.Jet electrolytic cell device includes: anode chamber, cathode chamber, cation exchange membrane, jet device and DC power supply device, wherein cation exchange membrane divides tank into anode chamber and cathode chamber, anode chamber is connected with DC power supply positive pole, cathode chamber is connected with DC power supply negative pole, cathode chamber and anode chamber adopt asymmetric structure.Jet device includes jet port and gas distribution plate, jet port is located at the bottom center of cathode chamber, gas distribution plate is arranged on the upper portion of jet port, gas distribution plate reduces the bubble diameter of gas entering cathode chamber, realizes bubble micro-fining, without additional stirring device;Compared with existing electrolytic cell device, the electrolytic energy consumption of preparing unit output rare earth compound is lower, and reaction gas utilization efficiency is higher.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of rare earth compound preparation, and particularly relates to a jet electrolytic cell device and method for continuously electro-converting to prepare a rare earth compound. BACKGROUND

[0002] With the rapid development of technology, rare earth elements are increasingly widely used. Rare earth is an important material for manufacturing electric vehicle batteries, especially lanthanum, cerium, praseodymium, neodymium and other elements in the lanthanum series, which play a key role in improving battery performance and prolonging 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 displays, optical fiber communication, magnetic recording materials and other aspects, and are the cornerstone of modern information technology. Rare earth materials are also widely used in missile guidance, radar systems, aerospace and other national defense fields, and are key materials for improving the performance of national defense equipment.

[0003] Rare earth carbonate is an important compound of rare earth elements. The application number CN202311578799.8 proposes a device for continuously electro-converting rare earth chloride to prepare rare earth compounds and its application. Through the design of the continuous electro-conversion device, the saturated rare earth chloride solution is one-step electro-converted to prepare rare earth hydroxide, oxide or rare earth carbonate. The invention realizes the preparation of rare earth compound materials in one step with rare earth chloride solution as raw material, realizes water solution circulation in the whole process, has no waste liquid discharge, and has no additional precipitating agent, which eliminates the problems of repeated consumption of acid and alkali and wastewater treatment and discharge from the source, realizes short process preparation of high-quality rare earth compounds, and realizes raw material recycling. However, the electrolysis process of the invention patent does not involve the utilization efficiency of the reaction gas and the energy consumption of the electrolytic cell.

[0004] The application number CN201710324342.2 discloses a method for preparing rare earth oxide by electro-converting rare earth chloride, which belongs to the field of rare earth hydrometallurgy. The method carries out pre-acid removal electrolysis on the rare earth chloride solution, and returns the hydrochloric acid to the rare earth production system; the rare earth chloride solution after pre-acid removal is used as electrolyte for electrolysis, 10℃≤temperature≤100℃, the voltage of electrolysis≥2.2V, high-purity carbon dioxide gas is introduced into the cathode zone during electrolysis, and stirring is carried out, and rare earth carbonate is directly prepared; in the cathode chamber, the electrolyte and the rare earth carbonate flow directionally, solid-liquid separation is carried out through a filtering device, and the filtrate and the rare earth carbonate are obtained, and the filtrate is circulated back to the cathode chamber; after the rare earth carbonate is dried and calcined, carbon dioxide gas and rare earth oxide product are prepared. The invention utilizes the electrolysis process, has simple process and low cost, recovers by-products hydrogen and chlorine to prepare hydrochloric acid which can be returned to the rare earth production system, and eliminates the pollution of ammonia nitrogen and other waste water, and finally high-purity rare earth oxide product is obtained. However, the invention patent does not involve the utilization efficiency of the reaction gas and the energy consumption of the electrolytic cell.

[0005] The prior invention utilizes an electrolysis process to prepare high-purity rare earth oxide products, eliminating the pollution of some waste water such as ammonia nitrogen; however, the utilization efficiency of the reaction gas in the preparation process of the rare earth compound is not considered, the utilization efficiency of the reaction gas is low, the consumption of the reaction gas is increased, and the purity of the hydrogen gas produced by the cathode is low, which is difficult to separate subsequently. SUMMARY

[0006] In view of the problems in the prior art, the purpose of the present application is to provide a jet electrolytic cell device and method for continuously preparing rare earth compounds by electroconversion, which comprises an anode chamber, a cathode chamber, a cation exchange membrane, a jet device and a direct current 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 center of the bottom of the cathode chamber, and a gas distribution plate is arranged 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 further significantly improve the utilization efficiency of the chlorinated rare earth solution electroconversion preparation of the rare earth compound and the electrolysis energy consumption.

[0007] To achieve the above purpose, the present application adopts the following technical solutions:

[0008] The present application provides a jet electrolytic cell device for continuously preparing rare earth compounds by electroconversion, which comprises an anode chamber, a cathode chamber, a cation exchange membrane, a jet device and a direct current 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 with the positive electrode of the direct current power supply, the cathode chamber is connected with the negative electrode of the direct current power supply, and the cathode chamber and the anode chamber adopt an asymmetric structure.

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

[0010] Further, the gas distribution plate is provided with uniformly distributed air holes, and the diameter of the air holes is ≤74 μm.

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

[0012] Further, the anode plate in the anode chamber is tightly attached to the cation exchange membrane by a flexible spring pressure net.

[0013] Further, the lower part of the anode chamber is provided with an anode liquid inlet, and the upper part is provided with an anode liquid outlet.

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

[0015] Further, the electrode plate of the anode chamber is a grid-shaped titanium plate, and the surface is coated with a ruthenium-iridium oxide layer.

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

[0017] The application also provides a method for continuously preparing rare earth compounds by using the jet electrolytic cell device, comprising the following steps:

[0018] Step 1: passing rare earth chloride aqueous solution into the anode chamber and passing sodium chloride solution into the cathode chamber;

[0019] Step 2: passing reaction gas through the jet gas outlet of the bottom jet device of the cathode chamber, and the reaction gas is dispersed through the gas distribution plate air holes to form fine bubbles;

[0020] Step 3: turning on the direct current power supply device, adjusting the current density, and reacting the fine reaction gas bubbles in step 2 with the rare earth cations entering the cathode chamber through the cation exchange membrane to directly prepare rare earth compounds;

[0021] Step 4: after electrolysis is completed, turning off the direct current power supply, taking out the electrolysis residual liquid of the anode chamber and the cathode chamber of the electrolytic cell, and closing the jet gas outlet of the jet device.

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

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

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

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

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

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

[0028] (1) In this invention, the anode chamber and the cathode chamber adopt an asymmetrical structure. The cathode chamber is equipped with a jetting device. The gas inlet (jet nozzle) is located at the bottom of the cathode chamber, and a gas distribution plate is provided at the top of the gas outlet. This reduces the diameter of the gas bubbles entering the cathode chamber and achieves bubble miniaturization. No additional stirring device is required. Compared with an electrolytic cell without a gas distribution plate, the carbon dioxide utilization efficiency is increased by nearly 60% when preparing rare earth compounds as rare earth carbonates.

[0029] (2) By using a flexible spring mesh to tightly bond the anode chamber electrode plate and the cation exchange membrane, the invention reduces the electrolysis energy consumption by more than 60% when preparing rare earth compounds of rare earth carbonate per unit yield, compared with the prior art. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a jet electrolyzer device for continuous electroconversion preparation of rare earth compounds according to the present invention.

[0031] Wherein: 1-Anode inlet; 2-Anode outlet; 3-Cathode inlet; 4-Cathode outlet; 5-Air jet; 6-Anode plate; 7-Cation exchange membrane; 8-Cathode plate; 9-Gas distribution plate; 10-Flexible spring mesh; 11-Ventilation hole; 12-Anode chamber; 13-Cathode chamber.

[0032] Figure 2 This is an exploded view of a jet electrolyzer apparatus for the continuous electroconversion preparation of rare earth compounds according to the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] Example 1

[0035] A jet electrolyzer apparatus for continuous electroconversion preparation of rare earth compounds, such as... Figure 1 The diagram shows an anode chamber 12, a cathode chamber 13, an ion exchange membrane 7, a jet nozzle 5, and a gas distribution plate 9. The anode chamber 12 has an anode inlet 1 at the bottom and an anode outlet 2 at the top. The cathode chamber 13 has a cathode inlet 3 at the bottom and a cathode outlet 4 at the top. A jet nozzle 5 is located at the center of the bottom of the cathode chamber 13, and a gas distribution plate 9 is located above the jet nozzle 5. The anode plate 6 is a grid-shaped titanium plate with a ruthenium oxide-iridium coating. A flexible spring mesh 10 tightly bonds the anode plate 6 to the ion exchange membrane 7. The cathode plate 8 is a grid-shaped nickel plate with a ruthenium oxide coating. The distance between the cathode plate 8 and the ion exchange membrane 7 is 1mm-5mm. Figure 2As shown, the gas distribution plate 9 is provided with uniformly distributed gas holes 11.

[0036] Example 2

[0037] A method for preparing a rare earth compound by using the jet electrolysis cell device for continuously electro-converting to prepare a rare earth compound of Example 1, wherein the jet electrolysis cell device has a gas hole 11 with a diameter of 74 μm, and the size of the cathode chamber is 5 times the size of the anode chamber, the rare earth compound is a rare earth carbonate, and the reaction gas is high-purity carbon dioxide gas, comprises the following steps:

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

[0039] Step 2: The bottom jet of the cathode chamber is opened, and high-purity carbon dioxide gas is introduced at a speed of 200 mL / min, and the gas bubbles are dispersed by the gas distribution plate to form fine carbon dioxide bubbles;

[0040] Step 3: The direct current power supply device is turned on, and the current density is adjusted to 800 A / m 2 , and the fine carbon dioxide bubbles in Step 2 react with the rare earth cations that pass through the cation exchange membrane into the cathode chamber to produce a rare earth carbonate precipitate by carbonization electrolysis;

[0041] Step 4: After the electrolysis is completed, the direct current power supply is turned off, the electrolyte in the anode chamber and the cathode chamber of the electrolysis cell is removed, and the bottom jet of the cathode chamber is closed.

[0042] Example 3

[0043] A method for preparing a rare earth compound by using the jet electrolysis cell device for continuously electro-converting to prepare a rare earth compound of Example 1, wherein the jet electrolysis cell device has a gas hole 11 with a diameter of 44 μm, and the size of the cathode chamber is 4 times the size of the anode chamber, the rare earth compound is a rare earth carbonate, and the reaction gas is high-purity carbon dioxide gas, comprises the following steps:

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

[0045] Step 2: The bottom jet of the cathode chamber is opened, and high-purity carbon dioxide gas is introduced at a speed of 200 mL / min, and the gas bubbles are dispersed by the gas distribution plate to form fine carbon dioxide bubbles;

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

[0047] Step 4: After electrolysis is completed, turn off the DC power supply, remove the electrolyte in the anode chamber and the cathode chamber of the electrolytic cell, and close the gas injection port at the bottom of the cathode chamber.

[0048] Example 4

[0049] A method for preparing a rare earth compound using the jet electrolytic cell device for continuous electro-conversion of a rare earth compound of Example 1, wherein the jet electrolytic cell device has a pore size of 37 μm for the gas injection hole 11 and the size of the cathode chamber is 3 times the size of the anode chamber, the rare earth compound is a rare earth carbonate, and the reaction gas is high-purity carbon dioxide gas, includes the following steps:

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

[0051] Step 2: Turn on the gas injection port at the bottom of the cathode chamber, and introduce high-purity carbon dioxide gas at a speed of 50 mL / min, which is dispersed by the gas distribution plate to form fine carbon dioxide bubbles;

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

[0053] Step 4: After electrolysis is completed, turn off the DC power supply, remove the electrolyte in the anode chamber and the cathode chamber of the electrolytic cell, and close the gas injection port at the bottom of the cathode chamber.

[0054] Example 5

[0055] A method for preparing a rare earth compound using the jet electrolytic cell device for continuous electro-conversion of a rare earth compound of Example 1, wherein the jet electrolytic cell device has a pore size of 20 μm for the gas injection hole 11 and the size of the cathode chamber is 2 times the size of the anode chamber, the rare earth compound is a rare earth carbonate, and the reaction gas is high-purity carbon dioxide gas, includes the following steps:

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

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

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

[0059] Step 4: After electrolysis is completed, turn off the direct current power supply, remove the electrolyte from the anode chamber and the cathode chamber of the electrolytic cell, and close the air inlet of the cathode chamber.

[0060] Comparative Example 1

[0061] A conventional electrolytic cell is used to prepare a rare earth compound by electroconversion. The rare earth compound is also a rare earth carbonate. High-purity carbon dioxide gas is passed through the electrolytic cell, including the following steps:

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

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

[0064] Step 3: Turn on the direct current power supply device and adjust the current density to 100 A / m 2 , carbonation electrolysis;

[0065] Step 4: After electrolysis is completed, turn off the direct current power supply, remove the electrolyte from the anode chamber and the cathode chamber of the electrolytic cell, and close the air inlet of the cathode chamber.

[0066] Comparative Example 2

[0067] Except that the jet electrolytic cell device for continuous electroconversion to prepare a rare earth compound does not have a gas distribution plate, the method for preparing a rare earth carbonate is the same as that of Example 5.

[0068] Energy consumption analysis

[0069] The energy consumption per kilogram of rare earth compound electrolysis is calculated according to the following formula:

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

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

[0072] Table 1 Energy consumption per unit time and unit yield of the rare earth carbonate electrolytic cell

[0073]

[0074] The carbon dioxide utilization efficiency is calculated according to the following formula:

[0075] Carbon dioxide utilization efficiency (%) = actual carbon dioxide consumption (mL) per unit time / carbon dioxide input (mL) per unit time

[0076] Table 2 Carbon dioxide utilization efficiency of rare earth carbonate electrolysis cell per unit time and per unit yield

[0077]

[0078] As shown in Tables 1 and 2, compared with the prior art Comparative Example 1, the electrolysis energy consumption per kilogram of rare earth carbonate in Example 2-5 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 electrolysis cell device for continuous electrochemical conversion to prepare rare earth compounds in the present application has excellent improvement in reaction gas utilization efficiency when preparing rare earth carbonate; the carbon dioxide utilization efficiency of Example 5 is increased by nearly 60% compared with Comparative Example 2, indicating that the gas distribution plate plays a significant role in improving the reaction gas utilization efficiency.

Claims

1. A jet electrolyzer apparatus for continuous electroconversion preparation of rare earth compounds, characterized in that, include: The tank comprises a cathode chamber, a cation exchange membrane, an air jet device, and a DC power supply. The cation exchange membrane divides the tank into an anode chamber and a cathode chamber. The anode chamber is connected to the positive terminal of the DC power supply, and the cathode chamber is connected to the negative terminal. The cathode and anode chambers have an asymmetrical structure. The size of the cathode chamber is 2-5 times that of the anode chamber. In the anode chamber, the anode plate and the cation exchange membrane are tightly bonded together using a flexible spring mesh. The distance between the cathode plate and the cation exchange membrane is 1mm-5mm. The jetting device includes a jet nozzle and a gas distribution plate. The jet nozzle is located at the center of the bottom of the cathode chamber, and the gas distribution plate is provided above the jet nozzle. The gas distribution plate is provided with uniformly distributed vent holes with a diameter ≤74μm.

2. The jet electrolyzer apparatus for continuous electroconversion preparation of rare earth compounds as described in claim 1, characterized in that, The anode chamber is provided with an anode inlet at the bottom and an anode outlet at the top; The cathode chamber is equipped with a cathode inlet at the bottom and a cathode outlet at the top. The rare earth compound product is precipitated and sent out of the electrolytic cell through the cathode outlet, thus realizing continuous production.

3. The jet electrolyzer apparatus for continuous electroconversion preparation of rare earth compounds as described in 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 its surface.

4. A method for continuously preparing rare earth compounds using a jet electrolyzer apparatus for continuous electroconversion of rare earth compounds as described in claim 1, characterized in that, Includes the following steps: 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 nozzle of the jet device at the bottom of the cathode chamber. 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 and adjust the current density. The micronized reaction gas bubbles in Step 2 react with the rare earth cations that have passed through the cation exchange membrane and entered the cathode chamber to directly obtain rare earth compounds. Step 4: After electrolysis is complete, turn off the DC power supply, remove the residual electrolyte from the anode chamber and cathode chamber of the electrolytic cell, and close the jet nozzle of the jet device.

5. The method for preparing rare earth compounds by continuous electroconversion as described in claim 4, characterized in that, The rare earth chloride aqueous solution in step 1 has a mass concentration of rare earth chloride component of 100 g / L-500 g / L; the sodium chloride solution in step 1 has a mass concentration of sodium chloride component of 20 g / L-200 g / L.

6. The method for preparing rare earth compounds by continuous electroconversion as described in claim 4, characterized in that, The flow rate of the reaction gas in step 2 is 50 mL / min to 500 mL / min.

7. The method for preparing rare earth compounds by continuous electroconversion as described in claim 4, characterized in that, The current density mentioned in step 3 is 300 A / m 2 -1000A / m 2 .

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