CN1009641B

CN1009641B - Process for producing cerium hydroxide

Info

Publication number: CN1009641B
Application number: CN 87100620
Authority: CN
Inventors: 金古次雄; 佐佐木秀一; 石川文矢; 下山胜
Original assignee: Mitsubishi Kasei Corp
Current assignee: Mitsubishi Kasei Corp
Priority date: 1986-02-18
Filing date: 1987-02-07
Publication date: 1990-09-19
Also published as: MY102131A; BR8700728A; CN87100620A; JPS62191422A

Abstract

To acidic aqueous solution containing Ce and other rare earth elements is divided into 2 fractions, one fraction is combined with an alkali and the formed solid and an oxidizing agent are added to the other fraction whereby the titled compound is readily obtained through a simple process with industrial advantage. An acidic aqueous solution containing Ce and other rare earth elements such as La, Pr, Nd is divided into 2 fractions and one fraction 1 is combined with an alkali hydroxide such as sodium hydroxide or ammonia to form a solid. At this time, an oxidizing agent such as air is preferably added thereto. The formed solid is rare earth metal hydroxides and th addition of an oxidizing agent makes Ce tetravalent Ce(OH)4. The solid is separated and admixed together with an oxidizing agent such as hydrogen peroxide to the other fraction 2. The mixing is preferably effected at 40 deg.C to room temperature. The mixture is preferably stirred at 60-80 deg.C for additional 2-6hr. All Ce is converted into Ce(OH)4 and the other rare earth hydroxides dissolve in water. The mixture is filtered to give Ce(OH)4 of high purity.

Description

Process for producing cerium hydroxide

The present invention relates to a kind of production method of cerous hydroxide.More particularly, it relate to a kind of from the acidic aqueous solution that contains the rare earth element beyond cerium and the cerium method of separation of hydrogen cerium oxide.

Method as separation of hydrogen cerium oxide a kind of acidic aqueous solution (following will being called briefly " raw material earth solution ") of the rare earth element beyond containing cerium and cerium it is believed that it is that a kind of oxygenant and rare earth metal hydroxide are joined (Japanese publication No. 96526/1985) in the raw material earth solution.

In the method, as rare earth metal hydroxide referred lanthanum hydroxide, neodymium hydroxide Neodymium trihydroxide, praseodymium hydroxide, samaric hydroxide, gadolinium hydroxide, yttrium hydroxide and their mixture thereof arranged, then used lanthanum hydroxide in an embodiment.Yet, this method industrial be disadvantageous, this be because rare earth metal hydroxide must be prepared respectively.

On the other hand, also having a kind of known method, wherein is the rare earth metal hydroxide that obtains from a part of earth solution after oxygenant and the separating cerium to be joined the raw material earth solution go (Japanese publication No. 96527/1985).But according to this method, a part of product after the separating cerium will carry out recirculation, and be used for recirculation amount will up to the separated cerium of desire etc. the gram molecular weight level.Therefore this method exists the drawback of production efficiency difference.

The present inventor has carried out deep research to seek a kind of method that obtains cerous hydroxide with high production efficiency from the raw material earth solution.Found that and to adopt the simple operations of certain specific program to obtain cerous hydroxide by a kind of.The present invention finishes on the basis of this discovery.

That is, the objective of the invention is and to produce cerous hydroxide in industrial favourable mode.This purpose can realize by the method for production cerous hydroxide of the present invention, comprising the acidic aqueous solution that contains cerium and cerium rare earth element in addition is divided into two batches, alkali metal hydroxide or ammonia are added first solution (1), separate the solid generated, then this solid and a kind of oxygenant are joined second batch of solution of batch-wise (2) thus in form the solid hydrogen cerium oxide.

Raw material earth solution used in the present invention is a kind of rare earth element acidic aqueous solution of lanthanum, praseodymium, neodymium or the like for example that contains beyond cerium and the cerium.

Rare earth element preferably is the form of muriate or nitrate.Acidity preferably is in pH value and is 6 level to the maximum, better is 3～5.

Come the present invention is explained in detail referring now to accompanying drawing.

Fig. 1 is the schema that a specific embodiment of the inventive method has been described.

The above-mentioned raw materials earth solution is divided into two batches.First (1) is introduced in solid and forms operation, and second batch (2) are introduced in mixed processes.

That this step that is divided into two batches preferably is performed such so that making the amount of first (1) is 0.5～2 times of amount of second batch (2), be 0.8～1.5 times better.If this ratio is too high, then the purity of the cerous hydroxide that generates just trends towards low.On the other hand, if this ratio is low excessively, although the purity of the cerous hydroxide that is generated improves, its output will be low.

Form in the operation at solid, be added in first (1) to generate the solid rare earth metal hydroxide such as sodium hydroxide or such alkali metal hydroxide or the ammonia of potassium hydroxide.Thereby alkali metal hydroxide is to be used with specified amount to make the pH value of solution be at least 10, is preferably 11～13.

Form in the operation at this solid, the adding of oxygenant is not main.Yet if oxygenant exists, that just might reduce the amount of oxygenant in the later mixed processes.In addition, employed oxygenant does not require it is strong oxidizer in solid-formation operation, can be oxygen containing gas such as air.So, preferably in this operation, add oxygenant.The amount of oxygenant preferably makes 1～50 mol that the trivalent cerous hydroxide in first (1) changes into the required theoretical amount of tetravalence cerous hydroxide doubly.

The solid that is generated is a rare earth metal hydroxide.When a kind of oxygenant was used, cerous hydroxide was that the form that is in oxidation is the tetravalence form.Filtrate (1) is the aqueous solution that contains corresponding to the alkali metal salts or ammonium salt of the acid of acid groups in the raw material earth solution.

In mixed processes, form the solid and a kind of oxygenant that obtain in the operation at above-mentioned solid and be introduced in second batch (2) and mixing.Here employed oxygenant is had no particular limits, as long as it can make tervalent cerous hydroxide change into the quaternary cerous hydroxide.For example, can use hydrogen peroxide or perchloric acid.The amount of using is that the trivalent cerous hydroxide in the mixed processes system is changed into the required theoretical amount of tetravalence cerous hydroxide at least, and preferably 1～2 mol of this theoretical amount doubly.

There is not special qualification in order by merging to above-mentioned three kinds of components.Yet preferably after being mixed, batch of material (2) and solid add oxygenant, so that avoid the excessive decomposition of oxygenant.Temperature is up to 50 ℃ usually, is preferably room temperature to 40 ℃.

Then, this mixture is heated to 40～100 ℃ temperature, is preferably 60～80 ℃, and reaction was then carried out under agitation condition 1～10 hour, was preferably 2～6 hours.

Through this operation, the oxyhydroxide of the rare earth element in the solid beyond the cerium is with dissolved, and solid will be a solid tetravalence cerous hydroxide with the cerium of criticizing in (2), and its separates the acidic aqueous solution that obtains highly purified cerous hydroxide and cerium rare earth element in addition through filtering.

Now, the present invention will be described in more detail with reference to embodiment.Yet must understand that the present invention is not subjected to the restriction of this specific examples.

Embodiment

11m as first indication of table 1 ³The raw material earth solution by batch (1): the ratio of batch (2)=6: 5 is divided into two batches.In batch (1), add 4m ³20% aqueous sodium hydroxide solution, simultaneously with 150m ³/ hour the speed input air, under 40 ℃, this mixture carried out 2 hours stirring then, thereby and stirs down at 70 ℃ and to form a kind of solid in 3 hours.

The mixture that generates becomes the solid of rare earth metal hydroxide by filtering separation and contains the filtrate of sodium-chlor.

Be mixed in batch (2) and suspension there through isolating solid like this.Then with 1 hour time and at 40 ℃ of aqueous hydrogen peroxide solutions that add down 78.5 liter 50% in this suspension, follow this mixture and be heated to 70 ℃ and accept 3 hours reaction.

Thereby this reaction mixture is filtered solid hydrogen cerium oxide that the rare earth that obtained to have the 2nd indication of table 1 forms and as the acidic aqueous solution as rare earth element beyond the cerium of the 3rd indication of table 1 of filtrate (2).

Table 1

The composition of the concentration PH rare earth element of contents identification rare earth element

(grams per liter is by oxidation (% presses oxide compound and calculates)

Thing calculates)

Beyond the cerium cerium

1 raw material earth solution 11.2 4.0 50.8 49.2

2 cerous hydroxide products--83.6 16.4

3 filtrates (2) 8.6 5.8 2.1 97.9

The method according to this invention just can be produced cerous hydroxide with industrial favourable mode, and this is because do not needed to prepare respectively the rare earth metal hydroxide of required use, does not also need product is carried out recirculation.Moreover, simply by the ratio that is divided into two batches is just changed and can easily adjust to required level to the concentration of cerous hydroxide.Therefore, method of the present invention is a kind of outstanding method.

Claims

1, a kind of method of producing cerous hydroxide is characterized in that:

The acidic aqueous solution of rare earth element is divided into two batches beyond cerium and the cerium containing, alkali metal hydroxide or ammonia are joined in first (1), separate the solid generated, this solid is joined in company with oxygenant in second batch (2) of solution in batches to generate the solid hydrogen cerium oxide;

Wherein, contain that the acidic aqueous solution of rare earth element has 3～6 pH value beyond cerium and the cerium, it is the muriate of rare earth element or the aqueous solution of nitrate.

2, method according to claim 1 is characterized in that said to be divided into two batches of amounts that must make first (1) be 0.5～2 times of second batch (2) amount.

3, method according to claim 1 is characterized in that said to be divided into two batches of amounts that must make first (1) be 0.8～1.5 times of second batch (2) amount.

4, method according to claim 1 is characterized in that oxygenant joins in first (1) in company with alkali metal hydroxide or ammonia.

5, method according to claim 4 is characterized in that oxygenant is oxygen containing gas.

6, method according to claim 1, it is 10～13 that the add-on that it is characterized in that alkaline earth metal hydroxides or ammonia should make the pH value after the adding.

7, method according to claim 1, it is characterized in that second batch (2) with add hydrogen peroxide again after the solid that obtains from first (1) mixes.

8, method according to claim 1, the amount with second batch of (2) blended hydrogen peroxide of it is characterized in that are to make 1 to 2 mol that trivalent cerous hydroxide in the system changes into the required theoretical amount of tetravalence cerous hydroxide doubly.

9, method according to claim 1, the mixture that it is characterized in that containing the solid that derives from first (1), oxygenant and second batch (2) are reacted under 40～100 ℃ temperature and stirring condition and are reached 1～10 hour.