SU899475A1 - Method for concentrating rare-earth elements and yttrium - Google Patents

Description

one

The invention relates to analytical chemistry, in particular to methods for concentrating impurities of rare earth elements and yttrium (REE) and can be used in analyzing various objects for the content of these elements.

A known method of concentrating REE impurities, including their extraction extraction with butyric acid from solutions containing ammonium nitrate and sulphosalicylic acid J1.

The disadvantage of this method is the increased laboriousness due to the extraction and repeated washing of the organic phase to remove impurities of non-rare-earth elements that interfere with the subsequent determination of REE. .

The disadvantage is also unsatisfactory sanitary working conditions due to the harsh unpleasant smell of the crazing agent.

There is also known a method for concentrating REE impurities, including their precipitation with oxalic acid in the form of oxalates 21.

The disadvantage of this method is the loss of REE, due to the increased solubility of REE oxalates of the yttrium subgroup. The dissolution of REEs is facilitated by the presence of admixtures of non-rare earth elements (especially

10 aluminum and iron), which form mixed complex compounds with REE and oxalate ion.

There is also known a method for concentrating REE impurities for them after s subsequent spectrographic determination, including treating a REE solution with ammonia, filtering the precipitate through a column filled with a fluoroplastic, washing the precipitate with a solution

Claims (2)

20 ammonia (for separating calcium), subsequent treatment of the precipitate with hydrofluoric acid and washing the REE from the hydrochloric acid column 38 The disadvantage of this method is incomplete extraction of REE in the concentrate (loss of REE is achieved and taken into account T1 | is introduced by introducing an internal cer-standard). the increased complexity of the process of concentration, due to the need for analytical operations to clean the concentrate of rare earth elements from impurities of rare earth elements falling into the concentrate and interfering after uyuschemu the definition of REE. The closest to the proposed technical essence and the achieved result is a method of concentrating impurities of rare-earth elements and yttri mainly for their subsequent analytical determination, including the processing of the sample being analyzed with hydrofluoric acid and the subsequent separation of the precipitate, in which it is concentrated with REE tAl. The disadvantage of this method is the increased complexity of the process of concentration, due to the need to conduct analytical operations to clean the REE concentrate from non-rare earth impurities that fall into the concentrate and interfere with the subsequent determination of R.E.E. Thus, separation of REE from calcium by re-precipitating REE hydroxides with ammonia solution, specially purified from carbonates, for separating REE oxalates from iron, aluminum and other elements. Another disadvantage is the incomplete extraction of REE in concentrate (the loss of trace amounts of REE is 20%) if the analyzed samples contain aluminum, iron, zirconium and some other elements forming mixed complex compounds with REE and fluoride ion. The purpose of the invention is to reduce the analysis (by eliminating analytical operations to clean up the REE concentration from non-rare earth impurities, which impede the subsequent determination of REE) and to improve the accuracy of the analysis (by eliminating noVepb REE, due to the increased solubility of REE fluorides in the presence of non-rare-earth elements forming mixed complex compounds with REE and fluoride ion). This goal is achieved in that the sample to be analyzed is treated with hydrofluoric acid, and the sample is passed through a layer of silicon dioxide to separate the precipitate. Example. Determination of trace amounts of REE and yttrium in the mineral raw materials of mining and geological enterprises of the rare metal industry. The analyzed material has a complex chemical composition. A 200 mg sample is placed in a glassy carbon (platinum) cup, moistened with water and heated with hydrofluoric acid, i.e. 15 ml of concentrated hydrofluoric acid, a few drops of perhydrol are added and evaporated on a plate to a volume of 2-3 ml. To uncover the mineral raw material, the processing operation of the sample with hydrofluoric acid is repeated twice. Next, the contents of the tea are diluted with water to 50 ml, and the mixture is passed through a layer of silica 300 mg placed in a Gooch's crucible. The silica layer is then washed with 10 ml of hot hydrofluoric acid. To carry out a photometric determination of REE, the contents of the Gooch crucible are washed into a glassy carbon (platinum) cup using 3 ml of concentrated hydrofluoric acid and 10 ml of sulfuric acid (1: 1) and evaporated to dryness. The dry residue is dissolved by heating in 10 ml of hydrochloric acid (1: 1), evaporated to wet salts and the residue is dissolved in 20 ml of t), 01 M hydrochloric acid. The solution is transferred to a 25 ml volumetric flask and made up to the mark with the same acid. The photometric determination of REE and yttrium was carried out by a known method using Arsenazo I or Arsenazo W as organic reagents. The correctness of the data obtained was controlled by the methods of additions and varying weights. The proposed method allows to significantly reduce the time of concentrating REEs (by eliminating a number of laborious analytical operations to separate REEs from those present in 3jieMeHTOB), as well as improve the accuracy of the analysis due to the absence of systematic losses of REEs during their concentration. Claims A method for concentrating rare-earth elements and yttrich, including treating the sample to be analyzed with hydrofluoric acid and separating the precipitate, mainly for subsequent analytical determination, characterized in that, in order to reduce the time and increase the accuracy of the analysis, to separate the precipitate, the sample is passed through a layer of silicon dioxide. Sources of information taken into account during the examination 1. Galkina LL, Glazunova L.А. Use of butyric acid for 54 extraction concentration of rare-earth elements - Journal of Analytical Chemical I.i. V. 21, no. 9, 1966, p: 1058-1063. 2. Methods of chemical analysis and the composition of minerals. Sat N., Science, 1971, p. 18-3-1. 3 Shmanenkova G.I., Zemskova M.G., Melamed Sh.G., Pleshakova G.P. Chemical-spectral determination of traces of rare earths (4x portions in rare-earth bases - Zavodskoy laboratories. V.38, N-9, 1972, p. 1088-1093. K. R bichikov d.R. Bukhin V.A. Analytical chemistry of rare-earth M. , Science, elements and yttria. 1966, p.7 “-78.