SU1723519A1 - Method of spectrophotometric analysis of rare-earth metals - Google Patents

Abstract

The invention relates to methods for the spectrophotometric determination of rare earth elements and can be used in the analysis of vanadium alloys. The purpose of the invention is to provide the possibility of determining yttri with high accuracy in vanadium alloys. The essence of the invention consists in adding to the analyzed sample sequentially ammonium chloride, sodium EDTA to the concentration in solution (1.9-2.6) (2.0-2.7). M, respectively, sodium molybdate permanganate ions and Arsenazo III and subsequent photometry of the resulting solution. 1 tab.

Description

The invention relates to analytical chemistry, mainly to spectrophotometric methods, and can be used in the quantitative determination of yttrium in vanadium-based alloys.

The purpose of the invention is to provide the possibility of determining yttri with high accuracy in vanadium alloys.

This goal is achieved by the fact that according to the method of spectrophotometric determination of yttrium, including the sequential introduction of molybdic acid (NaaMoO) and permanganate ions into a photometric solution of the sodium salt, before the addition of NaaMoO-q to the acid solution, additional solutions of the ethylenediaminetetraximetric sodium salt are added to the acidic solution and ammonium chloride.

PRI me R 1. A 0.1 g portion of the alloy is dissolved when heated in a mixture of HC104 acids (1: 1) and H2SO4 (1: 1), evaporated to wet salts and transferred into a 100 ml volumetric flask with a solution of H2 $ 04 (1: 4) up to the mark. An aliquot of a sample of 5–20 ml is taken into a 50 ml beaker, and 2.5 ml of a solution of sodium EDTA salt with a concentration of 5.37–10 2 M are introduced into it (in a photometric solution 50 ml its concentration will be 2.68-10 3 M), 10 ml of a 1.28 M solution of NH4Cl (50 ml in a photometric solution, its concentration will be 2.56 10 1 M), it is adjusted to a pH of 0.7-0.8, 10 ml of sodium molybdenum sulphate solution are added with a concentration of 100 mg in 1 ml of molybdenum (the solution is pre-neutralized to a pH of 6.5-7.0) and 0.5 ml of 0.01 n. of potassium permanganate solution. The solution is kept for 15-20 minutes, then it is adjusted with pH 3.5-3.6 with sulfuric acid (monitored by a pH meter), transferred to a 50 ml volumetric flask with 3 ml of a 0.1% arsenazo III solution being poured in and Mark up with water. Measurement

carried out with respect to a solution containing sodium molybdate, sodium EDTA, ammonium chloride, potassium permanganate and arsenazo III, at nm, 6 20-50 mm. The content of yttrium is determined by the graduation schedule or by calculation (see table).

It was introduced into the sample 2, wt.% Yttrium (including and for examples).

Found by the proposed method (2.45-2.55} Yu 2 wt.% Yttrium. Error + 2 rel.%.

PRI me R -2. The analysis is carried out as described in Example 1, but injected into the photometric solution 7, M of ammonium chloride.

Found in sample 3, wt.% Yttria. Error + 24 rel.%.

Example 3 The analysis was carried out as described in Example 1, but 4.1 10 M ammonium chloride was added.

Found in the sample of 1.4-1.0 wt.% Yttria. Error-44 rel.%.

. EXAMPLE 4 The analysis is carried out as described in Example 1, but injected into the photometric solution 1, EDTA sodium salt.

Measurement of the analytical signal is impossible due to the violation of the proportional relationship between the intensity of light absorption of solutions and the content of yttrium ..

EXAMPLE 5 The analysis is carried out, as described in example 1, but 5.4-10 M of the sodium salt of EDTA is introduced into the photometric solution.

Found in sample 1, wt.%. Yttria. Error-40 rel.%.

Example 6. The analysis is carried out as described in Example 1, but a 1.9-10 M solution of ammonium chloride and 2, M solution of the sodium salt of EDTA are introduced.

-2

0

five

0

five

0

five

0

The sample was injected with 1.0–10 wt.% Yttrium. It was found from the results of the spectrophotometric method 0.96–10 2 wt.%.

Example 7. The analysis was carried out as described in Example 1, but 2, M solution of ammonium chloride and 2, M solution of sodium EDTA were added.

Introduced in the sample of 2.5-10 wt.% Yttrium. Found on the results of the spectrophotometric method 2, wt.%.

Using the proposed method of determining yttrium by sequentially introducing into the analyzed acid solution ethylenediaminetetraacetic acid ions, ammonium, molybdate and permanganate ions, holding the solutions at pH 6.0-6.5 for 15-20 minutes, reducing the pH value up to 3.5-3.6 and the introduction of arsenazo 111 reagent allows its determination in vanadium-based alloys without preliminary stages of yttrium separation or separation of alloy components with a relative standard deviation value of 05-0.10.

Thus, the application of the proposed method improves the accuracy of yttrium determination in vanadium-based alloys.

Claims (1)

Formula invented shadows The method of spectrophotometric determination of rare-earth elements, including the sequential introduction of sodium molybdate, permanganate ions and arsenazo III into the analyzed solution, in order to enable the determination of yttrium with high accuracy in vanadium alloys , before adding sodium molybdate, ammonium chloride and sodium ethylenediaminetetraacetic acid are added to the analyzed solution to be concentrated in solution (1.9-2.6) and (2.0-2.7), respectively.