阅读说明：本技术 一种高纯碳酸铈中除铁的制备方法 (Preparation method for removing iron in high-purity cerium carbonate ) 是由 刘卫 杨泱 肖勇 崔小震 于 2020-12-24 设计创作，主要内容包括：一种高纯碳酸铈中除铁的制备方法,包括以下步骤：(1)取稀土相对纯度≥99.999％三价铈盐溶液,调节pH值至1～3,加入硝酸铈铵或硝酸高铈溶液；(2)在保温条件下搅拌,调节pH值至3.5～4.5,继续搅拌,过滤；(3)除铁后滤液进行碳酸沉淀,控制反应终点pH值为5.5～7.0,经洗涤及固液分离后,得到高纯低铁的碳酸铈晶体。利用本发明制得稀土纯度大于99.999％,铁小于1ppm的高纯碳酸铈产品。(A preparation method for removing iron in high-purity cerium carbonate comprises the following steps: (1) taking a trivalent cerium salt solution with the relative purity of rare earth being more than or equal to 99.999%, adjusting the pH value to 1-3, and adding ammonium ceric nitrate or ceric nitrate solution; (2) stirring under a heat preservation condition, adjusting the pH value to 3.5-4.5, continuously stirring, and filtering; (3) and (3) carrying out carbonic acid precipitation on the filtrate after iron removal, controlling the pH value at the end of the reaction to be 5.5-7.0, and washing and carrying out solid-liquid separation to obtain the high-purity low-iron cerium carbonate crystal. The high-purity cerium carbonate product with the rare earth purity of more than 99.999 percent and the iron content of less than 1ppm is prepared by the method.)

1. A preparation method for removing iron in high-purity cerium carbonate is characterized by comprising the following steps:

(1) taking a trivalent cerium salt solution with the relative purity of rare earth being more than or equal to 99.999%, adjusting the pH value to 1-3, and adding ammonium ceric nitrate or ceric nitrate solution;

(2) stirring under a heat preservation condition, adjusting the pH value to 3.5-4.5, continuously stirring, and filtering;

(3) and (3) carrying out carbonic acid precipitation on the filtrate after iron removal, controlling the pH value at the end of the reaction to be 5.5-7.0, and washing and carrying out solid-liquid separation to obtain the high-purity low-iron cerium carbonate crystal.

2. The method for removing iron in high-purity cerium carbonate according to claim 1, wherein the method comprises the following steps: in the step (1), the trivalent cerium salt solution is one or more of a cerium chloride solution, a cerium acetate solution and a cerium nitrate solution.

3. The method for removing iron in high-purity cerium carbonate according to claim 1 or 2, wherein: in the step (1), cerium salt or alkali is added to adjust the pH value to 1-3.

4. The method for removing iron in high-purity cerium carbonate according to claim 3, wherein the method comprises the following steps: the cerium salt is one or more of cerium carbonate, trivalent cerium hydroxide and basic cerium carbonate, and the alkali is one or more of ammonia water, ammonium carbonate and ammonium bicarbonate.

5. The method for removing iron in high-purity cerium carbonate according to claim 1 or 2, wherein: in the step (1), the adding amount of the ammonium ceric nitrate or the ceric nitrate in the ammonium ceric nitrate or the ceric nitrate solution is 2-10 times of the molar weight of iron in the cerium solution.

6. The method for removing iron in high-purity cerium carbonate according to claim 1 or 2, wherein: in the step (2), stirring for 10-60 min at the temperature of 10-100 ℃, adjusting the pH value to 3.5-4.5, and continuing stirring for 5-30 min.

7. The method for removing iron in high-purity cerium carbonate according to claim 1 or 2, wherein: in the step (2), cerium salt or alkali is added to adjust the pH value to 3.5-4.5.

8. The method for removing iron in high-purity cerium carbonate according to claim 7, wherein the method comprises the following steps: the cerium salt is one or more of cerium carbonate, trivalent cerium hydroxide and basic cerium carbonate, and the alkali is one or more of ammonia water, ammonium carbonate and ammonium bicarbonate.

9. The method for removing iron in high-purity cerium carbonate according to claim 1 or 2, wherein: in the step (3), the filtrate after iron removal is subjected to carbonic acid precipitation at the constant temperature of 40-60 ℃.

Technical Field

The invention relates to a preparation method for removing iron in high-purity cerium carbonate.

Background

Cerium is used as a rare earth element, has wide application, can be used as a grinding material, an oxygen sensor, a solid electrolyte, an ultraviolet absorbent, a catalyst, a pigment, a polishing material, a metal material additive and the like, however, high-purity cerium carbonate is required as a raw material in the field of chip grinding, and has extremely high requirements on non-rare earth impurities such as iron and alkali metal besides high requirements on rare earth impurities in the cerium carbonate.

For rarityThere is no good method for removing the trace iron in the soil solution, and the prior jarosite method, goethite method, hematite method and Fe (OH) method for removing iron in the solution₃Precipitation method, etc., and cerium carbonate products having an iron content of less than 1ppm cannot be obtained based on these several methods. The method for removing iron from an iron-containing solution disclosed in Chinese patent application No. 200610033105.2 comprises the steps of firstly oxidizing the iron-containing solution to convert ferrous iron into ferric iron, then adding iron yellow seed crystals, adjusting the pH value of the solution to 4.5-5.0, filtering after reaction, and optimally obtaining a filtrate with the iron content of about 3 mg/L. The method has the advantages that the whole preparation process is complex, the volume of the solution is increased after iron removal, the amount of wastewater is large, impurities in the rare earth solution are removed, other impurities are added, and the influence on the purity of the cerium carbonate product is large. The method for removing iron from iron-containing solution disclosed in the Chinese patent application with the application number of 201410225011.X comprises the steps of adding oxygen into a reaction kettle under the high-temperature condition to oxidize iron, and obtaining iron-removing solution through secondary iron removal. The method for precipitating iron from a zinc sulfate solution in the form of hematite disclosed in the Chinese patent application with the application number of 02824827.9 comprises the steps of firstly adjusting the zinc sulfate solution to a higher pH value by using alkali in yellow, then adding the hematite as hematite nuclei, and after the reaction is finished, controlling the iron content in the solution to be 65 mg/L. The method for removing iron by pyrolyzing the low-nickel sulfur nitric acid leachate disclosed in the Chinese patent application with the application number of 201710551876.9 is characterized in that the low-nickel sulfur nitric acid leachate is heated to the temperature of 100-150 ℃, and is pyrolyzed for 1-5 hours at constant temperature, so that ferric nitrate is decomposed into iron slag precipitate and oxynitride, and the iron content in the filtered solution is 40 mg/L. The study of the behavior and influence of iron impurities in the process of preparing high-purity magnesium bicarbonate solution by extracting and separating wastewater from rare earth from Liuhong Ji and the like, which aims to separate iron from magnesium bicarbonate by oxidizing and removing iron in the carbonization process, has poor iron separation effect.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation method for removing iron in high-purity cerium carbonate, which has the advantages of simple and convenient operation, small pollution and environment-friendly production.

The technical scheme adopted by the invention for solving the technical problems is as follows: a preparation method for removing iron in high-purity cerium carbonate comprises the following steps:

(1) taking a trivalent cerium salt solution with the relative purity of rare earth being more than or equal to 99.999 percent, adjusting the pH value to 1-3, adding ammonium ceric nitrate or ceric nitrate solution (serving as a strong oxidant to change ferrous ions into ferric ions, wherein the reaction formula is Fe²⁺+Ce⁴⁺＝Fe³⁺+Ce³⁺)；

(2) Stirring under a heat preservation condition, adjusting the pH value to 3.5-4.5, continuously stirring, and filtering;

(3) and (3) carrying out carbonic acid precipitation on the filtrate after iron removal, controlling the pH value at the end of the reaction to be 5.5-7.0, and washing and carrying out solid-liquid separation to obtain the high-purity low-iron cerium carbonate crystal.

Further, in the step (1), the trivalent cerium salt solution may be one or more of a cerium chloride solution, a cerium acetate solution, and a cerium nitrate solution.

Further, in the step (1), cerium salt or alkali is added to adjust the pH value to 1-3; the cerium salt can be one or more of cerium carbonate, trivalent cerium hydroxide and basic cerium carbonate, and the alkali can be one or more of ammonia water, ammonium carbonate and ammonium bicarbonate.

Further, in the step (1), the adding amount of the ammonium ceric nitrate or the ceric nitrate in the ammonium ceric nitrate or the ceric nitrate solution is 2-10 times of the molar amount of the iron in the cerium solution.

Further, in the step (2), stirring for 10-60 min under the condition of keeping the temperature at 10-100 ℃ (preferably 40-80 ℃), adjusting the pH value to 3.5-4.5, and continuously stirring for 5-30 min.

Further, in the step (2), cerium salt or alkali is added to adjust the pH value to 3.5-4.5; the cerium salt can be one or more of cerium carbonate, trivalent cerium hydroxide and basic cerium carbonate, and the alkali can be one or more of ammonia water, ammonium carbonate and ammonium bicarbonate.

Further, in the step (3), the filtrate after iron removal is subjected to carbonic acid precipitation at the constant temperature of 40-60 ℃.

The cerium carbonate with the rare earth purity of more than 99.999 percent can be obtained by the method, the iron content is less than 1ppm, the method has mild reaction conditions and is easy to filter, meanwhile, the method can not bring in impurities which are difficult to decompose, does not generate toxic and harmful gases, and has friendly production environment.

Drawings

FIG. 1 is an X-ray diffraction chart of high-purity cerium carbonate with low iron obtained in example 1 of the present invention;

FIG. 2 is a scanning electron micrograph of the high purity low iron cerium carbonate obtained in example 1 of the present invention.

Detailed Description

The present invention is further illustrated by the following examples.

Example 1

Referring to fig. 1, a method for removing iron from high-purity cerium carbonate comprises the following steps:

(1) 200L of cerium chloride solution with the concentration of 210g/L and the rare earth relative purity of 99.999 percent, the iron content of 25mg/L and the molar concentration of 0.4477mmol/L are taken, cerium carbonate is added under the stirring condition to adjust the pH value to 2.5, and 0.9L of ammonium ceric nitrate solution with the concentration of 0.5mol/L is added into the solution;

(2) stirring the solution, heating to 50 ℃, keeping the temperature and stirring for 30min, adding cerium carbonate to adjust the pH value of the solution to 4.0, continuously stirring for 20min, and filtering to obtain filtrate with the iron content of 0.13 mg/L;

(3) and adding an ammonium bicarbonate solution into the filtered solution for precipitation, keeping the temperature at 55 ℃, controlling the pH value at the end point of precipitation to be 6.0, and washing and filtering the precipitate to obtain the high-purity low-iron cerium carbonate.

The X-ray diffraction pattern of the high-purity low-iron cerium carbonate obtained in the example is shown in FIG. 1; the scanning electron micrograph of the obtained high-purity low-iron cerium carbonate is shown in FIG. 2. The results of the cerium carbonate analysis are shown in Table 1.

Detecting items	CeO2/TREO	Fe/M	TREO
				The result of the detection	＞99.999％	0.00003％	51.2％

Example 2

A preparation method for removing iron in high-purity cerium carbonate comprises the following steps:

(1) taking 1000L of a cerium acetate solution with the relative purity of 230g/L of rare earth being 99.999 percent, the iron content being 34mg/L and the molar concentration being 0.609mmol/L, adding ammonia water under the stirring condition to adjust the pH value to 3.0, and adding 3L of 0.58mol/L ceric nitrate solution into the solution;

(2) stirring the solution, heating to 80 ℃, keeping the temperature and stirring for 20min, adding ammonia water to adjust the pH value of the solution to 4.5, continuously stirring for 30min, and filtering to obtain filtrate with the iron content of 0.09 mg/L;

(3) and adding a sodium bicarbonate solution into the filtered solution for precipitation, keeping the temperature at 50 ℃, controlling the pH value at the end point of precipitation to be 5.5, and washing and filtering the precipitate to obtain the high-purity low-iron cerium carbonate.

The analysis results of the high purity low iron cerium carbonate obtained in this example are shown in Table 2.

TABLE 2

Detecting items	CeO2/TREO	Fe/M	TREO
				The result of the detection	＞99.999％	0.000018％	49.32％

Example 3

A preparation method for removing iron in high-purity cerium carbonate comprises the following steps:

(1) taking 500L of a cerium nitrate solution with the relative purity of 200g/L of rare earth being 99.999 percent, the iron content being 41mg/L and the molar concentration being 0.7341mmol/L, adding ammonium bicarbonate under the stirring condition to adjust the pH value to 2.5, and adding 1L of 0.85mol/L ceric nitrate solution into the solution;

(2) stirring the solution, heating to 40 ℃, keeping the temperature and stirring for 60min, adding ammonium bicarbonate to adjust the pH value of the solution to 4.2, continuously stirring for 10min, and filtering to obtain filtrate with the iron content of 0.24 mg/L;

(3) and adding an ammonium carbonate solution into the filtered solution for precipitation, keeping the temperature at 40 ℃, controlling the pH value at the end point of precipitation to be 6.5, and washing and filtering the precipitate to obtain the high-purity low-iron cerium carbonate.

The analysis results of the high purity low iron cerium carbonate obtained in this example are shown in Table 3.

TABLE 2

Detecting items	CeO2/TREO	Fe/M	TREO
				The result of the detection	＞99.999％	0.000051％	50.21％