RU2441087C1 - Method of extracting rare-earth metals yttrium (iii), cerium (iii) and erbium (iii) from water solutions - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: proposed method comprises contact of extragent containing rapic acid and inert latent solvent with water solution, mixing obtained mix, settling and phase separation. Kerosene is used as said inert latent solvent. Extraction is performed for 10-15 min in two steps at pH=4.5-5.5 and extragent-to-water solution ratio of 1:10. In first step, extraction is carried out at content of rapic acid in extragent of 5-7 vol. % with separation of cerium (III) and mix of yttrium (III) and erbium (III). In second step, extraction is carried out at content of rapic acid in extragent of 15-17 vol. % with separation of yttrium (III) and erbium (III).

EFFECT: higher efficiency of extraction and separation.

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Description

The invention relates to metallurgy, and in particular to a technology for processing ores and concentrates containing rare earth elements. The invention can be used in the technology of obtaining rare earth elements in the form of compounds and simple substances from eudialyte and loparite concentrates.

The well-known "Method for the separation of rare-earth metals" (patent RU No. 20099228, ex. March 15, 1994), including the extraction of metals with solutions of nitrogen-containing anion exchangers containing at least two organic radicals in an inert diluent, characterized in that the metals are extracted with solutions of amines and / or quaternary ammonium bases, two organic radicals in each of which are 2,4-diethyl octyl.

The disadvantage is the use of concentrated solutions of amines and salts of Quaternary ammonium bases, which are toxic compounds and require the use of salting out agents.

The well-known "Method for the extraction of neodymium from a concentrate of rare earth metals of the cerium subgroup" (patent RU No. 2030463, dp March 10, 1995), including the extraction of tributyl phosphate from nitrate solutions after electrochemical oxidation of cerium containing 300-400 g / l of the amount of rare earth oxides, to obtain a raffinate and subsequent re-extraction of neodymium from the organic phase, characterized in that, in order to increase the extraction of neodymium by obtaining a neodymium concentrate in a re-extract with a content of 3-10% praseodymium and raffinate in the form of a red concentrate of earth metals suitable for preparing polishing materials, a solution of a rare-earth metal concentrate with a content of 50-60% cerium oxide in a ratio of 1: (6-10) is introduced into the initial solution before extraction and the extraction is carried out at a mass ratio of the sum of rare-earth metals in the initial solution and the extractant 1: (0.6-0.8).

The well-known "Method for the extraction of rare-earth elements from acidic solutions" (patent RU No. 2172719, dp 08/27/2001), including the introduction into the initial solution of the organophosphorus reagent-collector in the form of dialkylphosphoric acid when the solution is purged with gas to produce and separated from the solution of rare-earth foam product, characterized in that the isolated foam product is treated with nitric or hydrochloric acid with a concentration of at least 4N at 70-100 ° C with the transfer of rare earth elements into a solution that is separated from the regenerated reagent-s abuser.

The disadvantages of the method are the use of concentrated acids for the regeneration of the extractant, the use of concentrated extractant, the need to carry out the process at elevated temperature.

The disadvantages are: the use of expensive tributyl phosphate, a high ratio of volumes of organic and aqueous phases, the need for preliminary oxidation of cerium to a tetravalent state for its satisfactory separation from other lanthanides.

A known method for the extraction of rare earth metals from their mixture (patent RU No. 2049133, items 27.11.1995), including countercurrent extraction with an organic solvent from an aqueous solution of rare earth metals and reextraction by treating the organic phase with an aqueous solution of mineral acid, the extraction is carried out with the conclusion of part of the extract, with its subsequent countercurrent reextraction in three stages: with the ratio O: B = (1-3) in the first stage, O: B = (3-5) and the withdrawal of part of the organic solvent with its direction into the main cycle in the second stage and with ratio O: B = (5-10) in the third stage.

The disadvantage of this method is the high consumption of extractant.

A known method of extraction of rare-earth elements from aqueous solutions (patent RU No. 2112067, d.p. 27.05.1998), adopted as a prototype and consisting in the fact that as an extractant use a technical lubricant, in its composition containing, wt.%: Oleic acid 10-12, triethalonamine 4.5-6.0, engine oil (inert diluent) - the rest, and extraction is carried out in the range 0 <pH <10 by continuously adjusting the optimum pH for no more than two hours.

The disadvantages are the introduction of toxic triethanolamine into the extractant and the significant process time (up to two hours).

The technical result is an increase in the efficiency of extraction extraction and separation of rare earth elements, a decrease in the duration of the process, and a decrease in the technogenic load on the environment.

The method of extraction of rare earth elements of yttrium (III), cerium (III) and erbium (III) from aqueous solutions, comprising contacting an extractant containing oleic acid and an inert diluent and an aqueous solution, mixing the mixture, settling and phase separation, characterized in that Kerosene is used as an inert diluent, and extraction is carried out with a duration of 10-15 minutes, pH 4.5-5.5 and a volume ratio of extractant and aqueous solution of 1:10 in two stages, and in the first stage, when the oleic acid content in the extractant is 5- 7 vol.% S divided it cerium (III) and a mixture of yttrium (III) and erbium (III), and the second stage at a content of oleic acid in the extractant 15-17 vol.% with separation of yttrium (III) and erbium (III).

The use of kerosene as an inert solvent provides a decrease in the viscosity of the extractant, which leads to a decrease in the duration of the process. The absence of triethanolamine in the extractant reduces its toxicity.

Carrying out the extraction at pH 4.5-5.5 and the ratio of the volumes of extractant and aqueous solution 1:10 is optimal for obtaining high coefficients of extraction and separation of cerium (III), yttrium (III) and erbium (III) during their extraction from aqueous solutions ( obtained experimentally).

The separation and extraction of cerium (III) and a mixture of yttrium (III) and erbium (III) in the first stage of extraction is maximum when the oleic acid content in the extractant is 5-7 vol.% (Obtained experimentally).

The separation of yttrium (III) and erbium (III) in the second stage of extraction is maximum when the oleic acid content in the extractant is 15-17 vol.% (Obtained experimentally).

The method is illustrated by drawings, where Fig. 1 shows a diagram of an experimental setup for the extraction and separation of yttrium (III), cerium (III) and erbium (III), Fig. 2 shows a diagram of the extraction extraction and separation of yttrium (III), cerium (III ) and erbium (III), Fig. 3 shows the experimental dependences of the distribution coefficients of yttrium (III), cerium (III) and erbium (III) on the pH of the aqueous solution, Fig. 4 shows the experimental dependences of the distribution coefficients of yttrium (III), cerium (III) and erbium (III) from the content of oleic acid in the extragen e.

The method is as follows. The extraction was carried out using a thermostated automated installation, a diagram of which is shown in figure 1. In a thermostated reactor with a stirrer, the specified amounts of extractant and aqueous solution were placed in a volume ratio of 1:10, respectively. A solution of technical oleic acid grade B-115 (TU 9145-172-4731297-94) in kerosene was used as an extractant. The duration of contact between the extractant and the aqueous solution necessary to achieve equilibrium was established experimentally and was 10 min. The duration of the separation did not exceed 15 minutes The control of the pH value was carried out using a pH meter pH-150 M with a combined electrode of the ESK-10601/4 brand. The content of the rare-earth element in the aqueous solution was monitored using a Spectroscan U. X-ray fluorescence analyzer.

Based on the dependences of the distribution coefficients of cerium (III), yttrium (III) and erbium (III) on the oleic acid content in the extractant in the range of 3 to 15 vol.% At a constant pH of 5, presented in figure 4, and the dependencies of the coefficients distribution of cerium (III), yttrium (III) and erbium (III) from the pH of the aqueous solution in the range of values from 3 to 5 with a constant oleic acid content in the extractant of 15 vol.%, presented in figure 3, the following extraction sequence was obtained: cerium (III) - erbium (III) - yttrium (III).

Changing the content of oleic acid in the extractant, carried out two-stage extraction and separation of cerium (III), erbium (III) and yttrium (III) according to the scheme depicted in figure 2.

An aqueous solution containing yttrium (III), cerium (III) and erbium (III) was neutralized to pH 5. The first extraction stage was carried out with an oleic acid content in the extractant of 5-7 vol.%. In this case, cerium (III) was extracted into the extractant with separation coefficients β _{Ce / Y} = 6, β _{Ce / Er} = 6. Next, an aqueous solution containing yttrium (III) and erbium (III) was sent to the second extraction stage, at which, with an oleic acid content of 15-17 vol.% Extractant, erbium (III) was extracted into the extractant with a separation coefficient β _{Er / Y} = four.

Claims (1)

The method of extraction of rare earth elements of yttrium (III), cerium (III) and erbium (III) from aqueous solutions, comprising contacting an extractant containing oleic acid and an inert diluent and an aqueous solution, mixing the mixture, settling and phase separation, characterized in that Kerosene is used as an inert diluent, and extraction is carried out for a duration of 10-15 minutes at a pH of 4.5-5.5 and a volume ratio of extractant and aqueous solution of 1:10 in two stages, and in the first stage, when the oleic acid content in the extractant is 5- 7 vol.% With section HAND cerium (III) and a mixture of yttrium (III) and erbium (III), and the second stage - when the content of oleic acid in the extractant about 15-17% with separation of yttrium (III) and erbium (III)..

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