Electronic-grade ceric ammonium nitrate and industrial production method thereof

Abstract

The invention discloses electronic-grade ceric ammonium nitrate and an industrial production method thereof. The production method comprises the following steps: receiving cerium chloride feed liquid from a rare earth extraction production process; adding ammonia water into the cerium chloride feed liquid to obtain a purified solution; diluting the purified solution with pure water to obtain a diluted solution; adding hydrogen peroxide into the diluted solution and applying an electric field; ammonia water is sprayed in a variable manner and added into the diluted solution, and a reaction solution containing cerium hydroxide is obtained under the reaction condition; solid cerium hydroxide is separated from the reaction solution; adding the obtained solid cerium hydroxide into concentrated nitric acid, and reacting to obtain a cerium nitrate solution; the method comprises the following steps: adding ammonium nitrate into a cerium nitrate solution, evaporating and crystallizing until crystallization begins, and slowly standing and crystallizing at normal temperature until no crystal is generated in a crystallized solution; and separating crystals from the crystallization solution to obtain ceric ammonium nitrate. According to the method, a compact process route is adopted, and the electronic-grade ceric ammonium nitrate is prepared while the yield is increased and the production cost is minimized.

Description

TECHNICAL FIELD

[0001] The present application relates to a production method of cerium ammonium nitrate. BACKGROUND

[0002] Cerium ammonium nitrate is a water-soluble orange complex with strong oxidizing property, which is mainly used as a catalyst and oxidant for organic synthesis, an initiator for polymerization reaction, and a corrosion agent for integrated circuits.

[0003] Currently, the synthesis process of cerium ammonium nitrate mainly includes: rare earth separation enterprises obtain cerium chloride solution through extraction separation, and prepare cerium carbonate through carbonation. Subsequent downstream processing uses cerium carbonate as raw material, dissolves it in acetic acid or nitric acid, and then prepares cerium hydroxide (IV) through oxidation and precipitation. The cerium hydroxide (IV) is dissolved in nitric acid, concentrated and crystallized under strong acidic conditions, and then the obtained crystalline product is dissolved in nitric acid, and cerium ammonium nitrate is prepared after adding ammonium nitrate solution and concentrating and crystallizing.

[0004] CN202410484715.2 discloses a semi-continuous production method of cerium ammonium nitrate, which includes: using Ce(NO3)3 as raw material to continuously produce cerium hydroxide (IV); and using the cerium hydroxide (IV) as raw material to continuously produce cerium ammonium nitrate.

[0005] CN201910287523.1 discloses a production process of electronic-grade cerium ammonium nitrate, which includes: (1) dissolving raw material cerium carbonate to form solution 1, adjusting solution 1 to be acidic to obtain solution 2, and keeping the solution at a constant temperature for 20-25 minutes; (2) adding cerium carbonate again to adjust the pH value, and then adjusting the pH value with ammonium bicarbonate aqueous solution to obtain a trivalent cerium solution; (3) filtering the trivalent cerium solution obtained in step (2) to obtain a refined filtrate; (4) heating the filtrate obtained in step (3) to evaporate and concentrate to obtain a concentrated solution; (5) cooling and crystallizing the concentrated solution obtained in step (4), and centrifuging to obtain cerium nitrate crystals, and then recrystallizing; (6) dissolving the high-purity cerium nitrate crystals in step (5); (7) oxidizing and precipitating the cerium nitrate solution obtained in step (6), and then performing plate and frame filtration, dissolution, filtration, evaporation crystallization, centrifugal dehydration, and packaging to obtain electronic-grade cerium ammonium nitrate product.

[0006] CN201510377239.5 discloses a preparation method of electronic grade cerium ammonium nitrate, which comprises the following steps: (1) adding 1 part of cerium carbonate into 1.5-2 parts of dilute nitric acid to form an acid solution; (2) adjusting the pH of the acid solution to 1.5-2 to obtain a mixed solution; (3) filtering the mixed solution obtained in step (2) through a 1000-mesh sieve to obtain a filtrate; (4) microfiltration to obtain a filtrate; (5) oxidation and precipitation to form a mixed solution containing precipitates; (6) heating the mixed solution to micro-boiling; (7) plate and frame filtration to obtain precipitates; (8) adding the precipitates into nitric acid to dissolve and form an acid solution, and filtering the acid solution to obtain a filtrate; (9) concentrating and crystallizing to obtain cerium ammonium nitrate crystals; and (10) centrifugal dewatering to obtain electronic grade cerium ammonium nitrate.

[0007] CN02125765.5 discloses a preparation method of high-purity cerium ammonium nitrate by electrolytic oxidation crystallization: a trivalent cerium compound is dissolved into a cerium nitrate solution and subjected to electrolytic oxidation to convert the trivalent cerium into tetravalent cerium, and then ammonium nitrate is added into the electrolytic solution to precipitate and crystallize, so as to obtain cerium ammonium nitrate products, and the post-precipitation solution can be returned to the dissolving process.

[0008] CN202310388376.3 discloses a crystallization and purification method of electronic grade cerium ammonium nitrate. The preparation of cerium ammonium nitrate solution: the crude cerium ammonium nitrate is added into water, and is dissolved by heating to obtain a cerium ammonium nitrate solution; primary crystallization: crystal seeds are added into the cerium ammonium nitrate solution, and crystallization is performed by cooling during stirring, and after reaching the final temperature, the temperature is kept constant for crystal growth; water washing and drying: after the crystallization is completed, the slurry is filtered, washed, and vacuum dried to obtain cerium ammonium nitrate crystals with a certain particle size; the obtained cerium ammonium nitrate crystals are repeatedly crystallized for 2-3 times to obtain electronic grade cerium ammonium nitrate products.

[0009] The above production method has poor continuity and high cost. Therefore, there is an urgent need for a compact and reliable process for industrial production of cerium ammonium nitrate. SUMMARY

[0010] One of the purposes of the present application is to provide an industrial production method of cerium ammonium nitrate.

[0011] According to one aspect of the present application, a production method of cerium ammonium nitrate is provided, comprising: receiving a cerium chloride solution from a rare earth extraction production process, with a REO equivalent concentration of 295-305 g / L, a pH value of 1-1.5, and a purity of CeO2 / REO>99.5%; adding ammonia water into the cerium chloride solution, and separating the solid precipitate after 2-8 min of reaction at 40-50℃ to obtain a purified solution with a pH value of 4-4.5; diluting the obtained purified solution with pure water until the REO equivalent concentration is 100-200 g / L to obtain a dilution solution; The hydrogen peroxide is added to the dilute solution under stirring, and reacts under the applied electric field at room temperature for 10-30 minutes; The ammonia is then sprayed into the dilute solution, and after the addition is completed, the solution is reacted at 25-35°C for 40-120 minutes until the solution color becomes light yellow, and then heated to 60-90°C, and reacted for 10-40 minutes to obtain a reaction solution containing cerium hydroxide; The solid cerium hydroxide is separated from the reaction solution; The obtained solid cerium hydroxide is added to concentrated nitric acid, and after the reaction, a cerium nitrate solution is obtained; The ammonium nitrate is added to the cerium nitrate solution, and after reacted at 80-90°C for 5-10 minutes, heated to boiling, and evaporated until the REO concentration is 230-260 g / L, and then slowly placed at room temperature until no more crystals are formed in the crystallization solution; The crystals are separated from the crystallization solution to obtain the ammonium cerium nitrate.

[0012] The production method according to the present application can further include returning the solid precipitate separated from the cerium chloride solution to the rare earth production process.

[0013] The production method according to the present application, wherein the hydrogen peroxide and the ammonia are preferably added to the dilute solution in an amount of 1.1-1.5 times the stoichiometric value.

[0014] The production method according to the present application, wherein the voltage of the applied electric field is preferably 0.5-5 V, and the current density is 0.1-1 A / m². The electric field can be provided by an electrode pair arranged in the container, which effectively promotes the oxidation of cerium (III) to cerium (IV), reduces the reaction activation energy, and increases the cerium hydroxide yield.

[0015] The production method according to the present application, wherein the spraying of the ammonia is preferably variable spraying based on the solution foaming condition, the spraying rate is 0.1-1 mL / min, and the droplet diameter is less than 100 μm. The spraying can be performed by an electrically controlled fine spraying head connected to a foam sensor and a control system, and the ammonia spraying rate is automatically adjusted according to the solution foaming condition. This variable spraying can effectively reduce the foam generation and optimize the reaction conditions.

[0016] The production method according to the present application, wherein the separated solid cerium hydroxide is preferably washed multiple times with hot water at 60-70°C until no chloride ions are left, and the first washing liquid is returned to the rare earth extraction production process, and the remaining washing liquid is reserved for the next washing. In this case, the washed solid cerium hydroxide can also be dried at 70-80°C.

[0017] The production method according to the present application can further include filtering the cerium nitrate solution and returning the filter residue to the rare earth production process.

[0018] According to the production method of the present application, the cerium nitrate solution can also be tested for impurity content before evaporation crystallization, and the testing indexes include La2O3, Pr6O 11 , Nd2O3, Sm2O3, Y2O3, Fe 2+ , SO4 2- , BaO, PbO, F - , Al2O3, Cl - , and the impurity content is controlled to be: La2O3<0.002%, Pr6O 11 <0.001%, Nd2O3<0.0002%, Sm2O3<0.0001%, Y2O3<0.001%, Fe 2+ ≤0.0001%, SO4 2- ≤0.0001%, BaO≤0.0001%, PbO≤0.0001%, F - ≤0.0001%, Al2O3≤0.0001%, Cl - ≤0.0001%; if the impurities exceed the standard, the cerium nitrate solution is additionally purified or the crystallization parameters are adjusted to ensure that the crystallization center is pure and the purity of cerium ammonium nitrate is improved.

[0019] According to the production method of the present application, the amount of ammonium nitrate added to the cerium nitrate solution is preferably 1-1.5 times the stoichiometric value.

[0020] According to the production method of the present application, the filtrate collected from the crystallization solution can also be returned to the rare earth production process.

[0021] According to the production method of the present application, the purity of the obtained solid cerium hydroxide is: CeO2 / REO>99.95%.

[0022] According to another aspect of the present application, there is also provided cerium ammonium nitrate produced according to the above method, and the purity is: CeO2 / REO>99.99%.

[0023] The present application uses cerium chloride (CeO2 / REO>99.5%) separated from the rare earth extraction production process as the raw material solution, and high-purity intermediate product cerium hydroxide (Ⅳ) (CeO2 / REO>99.95%) is prepared in a hydrochloric acid system, and then cerium ammonium nitrate is produced. The present application adopts a compact process route, which improves the yield (as high as 98% or more) and minimizes the production cost, and at the same time, electronic-grade cerium ammonium nitrate (CeO2 / REO>99.99%) is prepared. By introducing an electric field and variable spraying control, the reaction efficiency and product purity are further optimized. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below through specific embodiments, but these are not intended to limit the present invention.

[0025] 1) Receive cerium chloride feed solution directly from the rare earth extraction process, with an REO concentration of 302 g / L, a pH of 1.1, and a purity of CeO2 / REO > 99.5%. ICP-MS test results are shown in Table 1 below.

[0026]

[0027] While stirring (at 200 rpm), ammonia was added to the above cerium chloride solution to adjust the pH to 4.3. The temperature was maintained at 45°C for 5 minutes. The solid precipitate was then filtered off while still hot and returned to the extraction process. The volume of the filtrate (purified solution) was measured and recorded as V. 总 While stirring (at 200 rpm), ammonia water was added to the above cerium chloride solution to adjust the pH to 4.3. The temperature was maintained at 45°C for 5 minutes. Afterward, the solid precipitate was filtered off while hot and returned to the extraction process. The volume of the filtrate (purified solution) was measured and recorded as V. 总 .

[0028] The concentration of trivalent rare earth elements in the filtrate was determined by EDTA titration. 0.5 mL of the filtrate was taken into an Erlenmeyer flask and diluted 100 times with pure water to obtain a diluted solution. Two drops of bromocresol green standard solution were added sequentially, mixed well, followed by one drop of 1:1 diluted hydrochloric acid (36% analytical grade) solution, mixed well, 15 mL of 20% hexamine buffer solution, and four drops of 0.5% xylenol orange solution. The solution was then titrated with EDTA until a color change (from deep purple to bright green) was observed, and the titration volume V was recorded. 滴 C is calculated according to formula (1). RE 3+ =234.93g / L (equivalent to REO).

[0029] C RE 3+ =(V 滴 *M 稀 *C 滴 ) / V 取 Equation (1) C RE 3+ : Cerium oxide concentration in solution (equivalent to REO), g / L; V 滴 Titration volume, mL; M 稀 The relative molecular mass of rare earth elements is 172.12 g / mol; C 滴 : EDTA titrant concentration, g / L; V 取 : Sample solution volume, mL.

[0030] 2) Prepare a diluted cerium chloride solution Dilute the above filtrate with pure water to a concentration of 120 g / L, volume V 样 =1500mL, calculate the total mass of rare earth oxides in the solution according to formula (2) as m REO =180g.

[0031] m REO =C RE 3+ *V 样 Equation (2) 3) The intermediate product cerium hydroxide is generated. Measure 145 mL of 30% analytical grade hydrogen peroxide (1.3 times the theoretical value) and 410 mL of analytical grade ammonia (25%-28%) (1.2 times the theoretical value).

[0032] Hydrogen peroxide and ammonia were added to the diluted solution as described above: the stirring speed was 200 r / min, the H2O2 injection rate was 7 mL / min, and the NH3H2O ​​dropwise injection rate was 0.6 mL / min. After adding hydrogen peroxide, a micro-electric field was applied in the reaction vessel using a platinum electrode pair, with a voltage of 2 V and a current density of 0.5 A / m², for a reaction time of 20 min to promote the oxidation of cerium(III) to cerium(IV). Subsequently, ammonia was added dropwise using an electronically controlled fine spray head connected to a foam sensor and a PLC control system. The addition rate was automatically adjusted within the range of 0.1–1 mL / min based on the real-time foam level, and the spray droplet diameter was less than 100 μm to reduce foam formation. After the addition was completed, the solution was heated to 30 °C and reacted for 60 min (until the color of the reaction solution changed from orange-red to pale yellow); then heated to 85 °C and held for 30 min to obtain a reaction solution containing cerium hydroxide. The reaction process is as follows.

[0033] 2CeCl3+3H2O2+4H2O=2Ce(OH)3O·OH ↓+6HCl HCl + NH3·H2O = NH4Cl + H2O 2Ce(OH)3O·OH = 2Ce(OH)4 ↓ + O2 4) Separate solid cerium hydroxide The pale yellow reaction solution was filtered while hot, and the filter cake was washed five times with 65°C hot water (total volume of reaction solution: volume of washing solution = 1:25). The filtrates were collected five times, and the absence of chloride ions was ensured by titration with silver nitrate standard solution. The first washing solution was recycled to the rare earth extraction workshop for washing and reuse. The second, third, fourth and fifth washing solutions were collected and used for the next washing.

[0034] The filtered solid precipitate was transferred to an oven for drying at 75°C for 2 hours. The weight was then recorded. Ce（OH）4 =254.4g, grind into powder and set aside.

[0035] Take 0.1566g of the above-mentioned cerium hydroxide solid, add 15mL of sulfuric acid (1 part sulfuric acid to 2 parts water), and stir to dissolve at 85℃ for 20min at a speed of 200r / min. Make up to 50mL to obtain a diluted solution. Take another 15mL of the diluted solution, add 50mL of 5% sulfuric acid, 4 burettes of 20% urea, and 2 drops of benzoic acid. The volume of ferrous standard solution consumed is V1 = 7.98mL. Take another 15mL of the diluted solution, add 10mL of phosphoric acid and 3mL of perchloric acid, and heat on an electric furnace to dissolve the cerium hydroxide. 3+ Oxidized to Ce 4+ After cooling slightly, titrate using the same method. The volume of ferrous standard solution consumed is V2 = 8.01 mL. The oxidation rate is calculated to be 99.63% according to formula (3).

[0036] Oxidation rate (%) = V1 / V2 × 100 Equation (3) The yield of cerium hydroxide calculated according to formula (4) is 95.00%.

[0037] γ Ce（OH）4 =m Ce（OH）4 / (C RE 3+ ×V 总 ×M Ce（OH）4 / M Ce Equation (4) × 10 Where, γ Ce（OH）4 : Cerium hydroxide yield, %; m Ce（OH）4 Actual yield of cerium hydroxide, g; C RE 3+ : Concentration of rare earth elements in the solution (equivalent to REO), g / L; V 总 Total solution volume, mL; M CeO2 Molar mass of cerium oxide, 172.12 g / mol; M Ce（OH）4 : Molar mass of cerium hydroxide, 208.12 g / mol.

[0038] Referring to GB / T 14635-2020, the REO content is 74.53%, which is within the 60%~75% range and meets the requirements for electronic grade 3N5. ICP-MS test results are shown in Table 2 below.

[0039]

[0040] 5) Prepare cerium nitrate solution Prepare 192g of solid cerium hydroxide using the method described above and place it in a beaker. Then, measure 360mL of concentrated nitric acid (approximately 15.8mol / L) and add it directly to the beaker. Heat to boiling and stir for 20min until the solution is clear and free of precipitate. Filter through a 500-mesh screen, then add pure water to bring the volume to 1L (V). Rotate at 150r / min to obtain a cerium nitrate solution. The reaction equation is as follows.

[0041] Ce(OH)₄ + 4HNO₃ = Ce(NO₃)₄ + 4H₂O The residual acidity was tested by acid-base neutralization titration. 0.5 mL of cerium nitrate solution was diluted 100 times with pure water and then titrated with sodium hydroxide standard solution. The titration volume V was recorded. 滴 =5.73mL, residual acid =3.9mol / L. The cerium oxide concentration was determined by ferrous ammonium sulfate titration. 0.5mL of cerium nitrate solution was taken and titrated according to the above method. The titration volume V was recorded. 滴 =16.08mL, C CeO2 =151.23g / L (equivalent to REO).

[0042] 6) Weigh out ammonium nitrate Calculate the amount of solid ammonium nitrate m according to formula (5). NH4NO3 =214.8g, for later use.

[0043] m NH4NO3 =1.42×C CeO2 ×V (5) 7) Production of cerium ammonium nitrate crystals Before evaporation and crystallization, the cerium nitrate solution was tested for impurities, and La2O3 and Pr6O were detected using ICP-MS and ion chromatography. 11 Nd₂O₃, Sm₂O₃, Y₂O₃, Fe 2+ SO4 2- BaO, PbO, F - Al2O3, Cl - Impurities, with control parameters as follows: La2O3 < 0.002%, Pr6O 11 <0.001%, Nd2O3<0.0002%, Sm2O3<0.0001%, Y2O3<0.001%, Fe 2+ ≤0.0001%, SO42- ≤0.0001%, BaO≤0.0001%, PbO≤0.0001%, F - ≤0.0001%, Al2O3≤0.0001%, Cl - ≤0.0001%. If impurities exceed the limit, the cerium nitrate solution should be further purified (e.g., by treatment with ion exchange resin) or the crystallization parameters should be adjusted (e.g., by lowering the crystallization temperature or extending the settling time) to ensure the purity of the crystallization center.

[0044] After adding the above-mentioned ammonium nitrate solid to the above-mentioned cerium nitrate solution, the mixture was placed on an electric furnace and heated to 85°C, with continuous stirring to dissolve it. The reaction was carried out for 7 minutes at a speed of 150 r / min, and then heated to boiling. The water was then evaporated to C. CeO2 =Approximately 250g / L (solution volume approximately 600mL). After crystallization begins, turn off the heat, transfer to a room temperature environment, and allow to crystallize slowly until no more crystals are formed at room temperature.

[0045] 8) Filtration and washing The solid is separated by filtration, and the filtrate is collected and returned to the production section to avoid waste. The solid is dried in a 60℃ oven for 30 minutes, then stored in a sealed container, weighed, and recorded as m. 硝酸铈铵 =475.5g.

[0046] According to XB / T221-2022, the oxidation rate was tested at 99.40%, which is greater than 99% and meets the requirements for electronic grade 4NA.

[0047] Referring to XB / T221-2022, the tested acidity concentration ratio is 1.08, which is within the range of 0.9-1.1 and meets the requirements for electronic grade 4NA.

[0048] According to GB / T 14635-2020, the REO content is 31.65%, which is greater than 31%, and meets the requirements for electronic grade 4NA.

[0049] The yield of cerium ammonium nitrate was calculated to be 98.71% using the following formula (6).

[0050] γ 硝酸铈铵 =m 硝酸铈铵 / (C CeO2 ×V 总 ×M 硝酸铈铵 / M CeO2 Equation (6) is calculated as follows: (1) × 100% Where, γ 硝酸铈铵 : Yield of cerium ammonium nitrate, %; m 硝酸铈铵 Actual yield of cerium ammonium nitrate, g; C CeO2 : Mass concentration of cerium oxide in solution (equivalent to REO) as determined by the ferrous ammonium sulfate method, g / L; V 总 Total solution volume, mL; MCeO2 Molar mass of cerium oxide, 172.12 g / mol; M 硝酸铈铵 The molar mass of cerium ammonium nitrate is 548.26 g / mol.

[0051] The ICP-MS test results are shown in Table 3 below.

[0052]

Claims

1. A method for producing cerium ammonium nitrate, comprising: The feed solution of cerium chloride from the rare earth extraction process is received, with a REO concentration of 295-305 g / L, a pH of 1-1.5, and a purity of CeO2 / REO > 99.5%. Ammonia water was added to the cerium chloride solution, and the reaction was carried out at 40℃~50℃ for 2~8 min. The solid precipitate was then separated to obtain a purified solution with a pH value of 4~4.

5. The purified solution was diluted with pure water until its REO equivalent concentration was 100-200 g / L to obtain a diluted solution. First, add hydrogen peroxide to the diluted solution while stirring, and react for 10-30 minutes at room temperature under an applied electric field. Then spray ammonia water into the diluent. After the addition is complete, react at 25~35℃ for 40~120min until the solution turns pale yellow. Then heat to 60~90℃ and keep the temperature for 10~40min to obtain a reaction solution containing cerium hydroxide. Solid cerium hydroxide was separated from the reaction solution; The obtained solid cerium hydroxide was added to concentrated nitric acid, and a cerium nitrate solution was obtained after the reaction. Ammonium nitrate is added to cerium nitrate solution and reacted at 80-90℃ for 5-10 minutes. Then it is heated to boiling and the water is evaporated until the REO concentration is 230-260 g / L. After crystallization begins, it is allowed to stand at room temperature for crystallization until no more crystals are formed in the crystallization solution. Cerium ammonium nitrate is obtained by separating the crystals from the crystallization solution.

2. The production method according to claim 1 further includes: The solid precipitate separated from the cerium chloride solution is then returned to the rare earth extraction production process.

3. The production method according to claim 1, wherein the amount of hydrogen peroxide and ammonia added to the dilution solution is 1.1 to 1.5 times the stoichiometric value.

4. The production method according to claim 1, wherein the voltage of the applied electric field is 0.5 to 5V and the current density is 0.1 to 1A / m².

5. The production method according to claim 1, wherein the ammonia spraying is a variable spraying based on the foaming condition of the solution, the spraying rate is 0.1 to 1 mL / min, and the diameter of the sprayed droplets is less than 100 μm.

6. The production method according to claim 1, wherein the separated solid cerium hydroxide is washed multiple times with hot water at 60~70℃ until no chloride ion residue remains, the first washing solution is returned to the rare earth extraction production process, and the remaining washing solution is reserved for the next washing.

7. The production method according to claim 4 further includes drying and cleaning the solid cerium hydroxide at 70~80°C.

8. The production method according to claim 1, wherein the amount of ammonium nitrate added to the cerium nitrate solution is 1 to 1.5 times the stoichiometric value.

9. The production method according to claim 1, wherein the purity of the obtained solid cerium hydroxide is: CeO2 / REO > 99.95%.

10. The cerium ammonium nitrate produced by the method according to any one of claims 1-9 has a purity of: CeO2 / REO > 99.99%.

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