SU1444301A1 - Method of separating lanthanum from rare-earth elements of the cerium group - Google Patents

Abstract

The invention relates to methods for separating lanthanum from rare earth elements (REE) of the cerium group and allows for increasing the separation factor. Separation is carried out by adding the alkylphosphonic acids or their monoethyl esters in stoichiometric proportions to the initial solution (L- (o-hydroxyphenoxy)). em 1050 (according to the prototype, the separation factor does not exceed 360). I CO

Description

This invention relates to the chemistry of rare earth elements (REE) and can be used in the separation of lanthanum from any REE of the cerium group or their mixture.

Lanthanum - one of the most common rare-earth elements - has its own field of application, in particular in wide-angle optics. Therefore, the separation of lanthanum from REE of the cerium group is an important technological problem.

The purpose of the invention is to increase the separation rate of lanthanum from REE of the cerium group.

The goal is achieved by a single treatment of an aqueous solution of a mixture of REE salts (for example, chlorides or nitrates) of the cerium group with a complexing agent. To an aqueous solution of a mixture of salts of REE cerium group is added an aqueous solution of about- (o-hydroxyphenoxy) alkyl

PHOSPHONIC ACID or MONOED STABLE

ester of this acid, taken in a stoichiometric ratio, followed by the separation of the precipitate containing REE complexes, except for lanthanum, while lanthanum remains in solution.

When a scientific research institute is deposited once, the separation coefficient of lanthanum is f050.

The advantage of the proposed method is a high separation factor, the simplicity of the separation technique and instrumentation.

Example 1. Separation of a mixture of La (NOj) j and NdCNOj) ,.

To a mixture of finely divided La (NOj) and Nd (NO) j, taken in an amount of 0.433 and 0.438 g, respectively (molar ratio of La: Nd: 1: 1), 10 ml of water were added and an aqueous solution (5%) was added to the resulting solution. ml) o-hydroxyphenoxymethylphosphonic acid (HjjL) (0.876 g). The solution is stirred at room temperature for 24 hours. The precipitation is filtered off, rinsed with a small amount of water, dried in air.

A spectrophotometric analysis of the filtrate obtained after separation of the precipitate of the Nd complex showed that the solution contains almost no Nd (with an error of determination by the spectrophotometric method). The filtrate is evaporated to dryness, the residue is analyzed for La content.

According to the analysis results, the filtrate contains 100 + 3% La. The precipitate of the complex is dissolved in 3 ml of 20% HC1 plant, diluted to 50 ml with water, and Nd oxalate is precipitated at 60 ° C with a saturated solution of HjCjO. The oxalate is dried and converted to oxide by calcination at 1000 ° C. The resulting oxide is dissolved in 5 ml of concentrated HCl, diluted with water to 50 ml and analyzed for Nd content by a spectrophotometric method (A 575 nm). According to the results of the analysis, the resulting oxide contains 100 ± 3%. The separation ratio of the La-Nd mixture is about 1050.

Example 2. Separation of a mixture of LaCl j and PrCl j.

0 To a mixture of finely divided LaClj and PrClj, taken in an amount of 0.433 and 0.870 tons, respectively (molar ratio LarPr 1: 2), 15 ml of water are added and to the resulting solution

5, an aqueous solution (7 ml) (o-hydroxyphenoxy) benzylphosphonic acid () was added, taken in an amount of 1.326 g (molar ratio LarPr: 1: 2: 3). The solution is stirred

Q at room temperature during the day. Inserted precipitate is filtered off, washed with a small amount of water, dried in air. The results of the SF-analysis of the filtrate obtained after separating the precipitate of the complex Pr, showed that the mother liquor contains almost no Pr. According to the results of the analysis, the filtrate contains 100 + 3% La.

During the deposition of REEs in these examples, the formation of low soluble REE complexes of composition HML and ML -2H20 for acids and their esters, respectively.

five

0

These complexes are not previously described in the literature. The individuality of the complexes obtained is proved by the methods of elemental analysis. IR spectroscopy, X-ray phase and thermal analysis.

Claims (1)

Invention Formula The method of separating lanthanum from the rare-earth elements of the cerium group by treating the initial aqueous solutions of the salts with a complexing agent, characterized in that  144A301 In order to increase the ratio between the ratio and the complex compound, some lanthanum is separated as a complexing agent in a completely aqueous solution using an aqueous solution of an .- (o-hydroxy-solution from insoluble complex phenoxy) alkylphosphonic acids or them. compounds of the rare-earth elements of monoethyl ethers in the stoichiometric group.