RU2060944C1 - Method for isolation of europium from mixture of rare-earth elements - Google Patents

Abstract

FIELD: inorganic chemistry. SUBSTANCE: sulfate solution which contains rare-earth elements is treated by sodium fluoride and by metallic aluminium. Thus obtained precipitate is separated of solution. Degree of extraction of europium is 98.5 %. EFFECT: improves efficiency of method.

Description

 The invention relates to the chemical technology of rare earth elements and can be used in the manufacture of europium products.

Known methods for the separation of europium, based on the restoration of it to a divalent state in solutions of salts of a mixture of REE and subsequent separation in the form of a sparingly soluble precipitate [1,2]
The disadvantages of the chemical methods used to isolate europium from the REE mixture are the need for expensive and toxic reagents (mercury, lead, zinc, hydrochloric and acetic acids), the complexity of the equipment, the problem of disposal of liquid effluents containing chlorine, zinc, etc.

 Of the reducing metals, aluminum is relatively cheap and non-toxic.

 The method using aluminum to transfer europium to the divalent state [2] is simple to implement.

 However, aluminum (in the form of an amalgam) reduces europium only in hydrochloric acetic acid solutions. This affects the sanitary conditions of the process.

 The proposed method avoids the above disadvantages of the known chemical methods for the isolation of europium from a mixture of REE.

The essence of the proposed method consists in the fact that europium is reduced with aluminum metal (dust, powder, granules) in a sulfuric acid solution of REE in the presence of fluoride ions introduced in the form of water-soluble compounds, for example, NaF, NH ₄ HF ₂ , HF, etc. process indicators affect the temperature and pH of the medium, the duration of pulp agitation and the ratio of aluminum and fluorine introduced.

The proposed method makes it possible to extract from the amount of REE up to 98.5% europium and obtain a product containing up to 99.9% europium. Depending on the quality requirements of the europium end product, process parameters can vary in the following ranges: pH of the medium 0.1-5.0 Pulp temperature, ^о С 5-50
The amount of input
aluminum, from stoichiometrically necessary 100-300
The amount of input
fluorine by weight of aluminum introduced 0.045-0.45 Pulp agitation time, h 0.5-3.5
PRI me R 1. In a sulfuric acid solution with a concentration of H ₂ SO ₄ 24.5 g / DM ³ , RE ₂ About ₃ 100 g (including 9.8 g of europium) was made 15 g of aluminum (powder, grade PA -4) and 10 g of NaF, then stirred for 90 min at room temperature. The output of europium in the filtered and washed precipitate 98.1% of the content of europium in the amount of RE ₂ O ₃ precipitate 94.2%
EXAMPLE EXAMPLE 2 In similar to the first sulfate solution was added 20 g of aluminum and 10 g of NaF, followed by stirring for 1.5 hours at 40 ^C. The yield of europium in the filtered and washed precipitate was 98.3% of the content of europium in the amount of RE ₂ O ₃ precipitate 98.5%
The obtained filtrates were used in the manufacture of stock solutions.

 Thus, the proposed method for the separation of europium from REE in comparison with known chemical methods can improve the extraction and quality of europium, use cheaper and less toxic reagents, and solve the problem of disposal of liquid effluents.

Claims (1)

 The method of separation of europium from a mixture of rare earth elements, including the reduction of europium (III) to europium (II) in an acidic solution with aluminum metal, the precipitation of europium concentrate and its separation from a solution of salts of rare earth elements, characterized in that the reduction of europium is carried out in a sulfuric acid medium in the presence of fluorine ions.