RU2440853C2 - Method of extracting ions of erbium from water solutions using sodium dodecyl sulphate - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to production of pure rare-earth metals or their oxides from low-grade or technogenic stock by ion flotation. Said ion flotation comprises using sodium dodecyl sulphate as a collector in concentration corresponding to stoichiometric reaction: Me⁺³+3DS^-=Me[DS^-]₃, where Me⁺³ is metal cation, DS^- is dodecyl sulphate-ion. Erbium salts are used as extracted ions. Note here that maximum yield of erbium is reached at pH=6.4.

EFFECT: increased extraction of erbium ions.

1 dwg, 1 tbl

Description

The invention relates to enrichment, in particular to methods for producing rare-earth metals (REM) or their oxides from poor or man-made materials using the ion flotation method.

A known method for the extraction of lanthanides, in particular, erbium cations, by flotation: (Szeglowski Z., Bittner-Jankowska M, Mikulski J. // Nucleonika, 1973, v. 18, No. 7, p. 299-307) - used as a collector anionic surfactant. Flotation recovery in this case was 95%. The specified method does not provide complete extraction of erbium ions from solutions.

A known method for the extraction of heavy metals, such as silver, zinc, lead, nickel and platinum, using ion flotation, using isopropylmethyl ethyl carbamate as the collector (Engel M.D., Moxon N.T .: patent No. WO 9217614, FR).

It is known that sodium dodecyl sulfate is used in the flotation process as a collector for the extraction of metals such as copper, cobalt, nickel, selected as a prototype (Skrylev L.D., Borisov A.V. On the efficiency of flotation separation of copper and nickel from wastewater of the Norilsk mining Metallurgical Combine // Journal of Applied Chemistry. 1978. V.51. No. 2, p. 344-436).

The technical result of the invention is the use of such a foaming agent in the flotation process of erbium ions, such as sodium dodecyl sulfate.

The technical result is achieved in that in a method for extracting erbium ions from solutions, including ion flotation using sodium dodecyl sulfate as a collector in a concentration corresponding to the stoichiometric reaction:

Me ⁺³ + 3DS ^- = Me [DS ^- ] ₃ ,

where Me ⁺³ is a metal cation, DS ^- is a dodecyl sulfate ion, according to the invention, erbium salts are used as recoverable ions, while ion flotation is carried out at a pH of 6.4 to maximize erbium extraction.

The REM extraction parameter is the distribution coefficient K: the K value of the extracted ion between the aqueous and organic phases was calculated by the ratio of the concentration of [Me ⁺³ ] (Er ⁺³ ) in the foam to the concentration of [Me ⁺³ ] in the chamber residue according to the formula: K = [Me ⁺³ ] _org / [Me ⁺³ ] _aq (FIG. 1). The distribution coefficient of rare earth metals (REM) between the aqueous and organic phases depends on the pH of the solution. For the most complete separation of REMs, aqueous solutions of erbium (III) nitrates with a concentration of 0.001 mol / L were used as model solutions; as a surfactant, sodium dodecyl sulfate, the concentration of which corresponded to the stoichiometry of the reaction. Data on the distribution coefficient in the studied solutions are presented in Table 1.

The method of extraction of erbium ions by flotation is carried out in a flotation machine of a mechanical type. In solution, rare-earth metal ions form stable complexes with surfactants, which, due to the hydrophobicity of alkyl radicals, pass into the foam phase. The drawing shows the dependence of the distribution coefficients of erbium ions on the pH of the solutions. The graph shows that the optimal pH value at which erbium ions are extracted from the solution = 6.4. REM extraction reaches 99.9%. For example: The process of ion flotation was carried out in a high-performance apparatus - a laboratory flotation machine of mechanical type 137 V-FL, with a chamber volume of 1.0 dm ³ , requiring a small amount of production space. 200 ml of a solution containing REM and a stoichiometric amount of sodium dodecyl sulfate were floated. The resulting solution (foam product) and the solution remaining in the cuvette after flotation (chamber residue) were analyzed for the content of the rare-earth element.

Table 1 presents experimental data on the flotation of erbium ions from solutions of its salts using sodium dodecyl sulfate. It is clearly seen that at pH 6.4 the maximum extraction of erbium cations is achieved.

Table 1 K distribution of erbium ions at various pH values of solutions pH [Er ⁺³ ] in the chamber residue, 10 ⁴ · mol / l [Er ⁺³ ] in the foam, 10 ⁴ · mol / l To the _{distribution.} 1.76 3,902 18.44 4.73 3.06 1,991 8.72 4.38 3.49 1,744 6.93 3.97 4.24 1,798 6.48 3.63 5.20 1,699 13.33 7.78 5.35 1,744 11.62 6.67 6.19 0.796 9.50 11.94 6.43 0,020 11.40 566.67 6.52 0.018 10.84 606.25 7.30 0.011 7.04 630.00 8.40 0.019 12.40 693.75 9.27 0.019 12.52 700.00

Claims (1)

A method of extracting erbium ions from a solution, including ion flotation using sodium dodecyl sulfate as a collector in a concentration corresponding to the stoichiometric reaction:
Me ⁺³ + 3DS ^- = Me [DS ^- ] ₃ ,
where Me ⁺³ is a metal cation, DS ^- is a dodecyl sulfate ion, characterized in that erbium salts are used as recoverable ions, while ion flotation is carried out at a pH of 6.4 to maximize erbium extraction.

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