GOST 23862.6-79

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  ГОСТ 23862.6-79

GOST 23862.6−79 Rare-earth metals and their oxides. Methods for the determination of sodium, potassium and calcium (with Amendments No. 1, 2)

GOST 23862.6−79

Group B59

INTERSTATE STANDARD

RARE EARTH METALS AND THEIR OXIDES

Methods for the determination of sodium, potassium and calcium

Rare-earth metals and their oxides. Methods of determination of sodium, potassium and calcium

ISS 77.120.99
AXTU 1709

Date of introduction 1981−01−01

The decision of the State Committee USSR on standards on October 19, 1979 N 3988 date of introduction is established 01.01.81

Limitation of actions taken by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (ICS 11−95)

EDITION with Amendments No. 1, 2 approved in April 1985, may 1990 (IUS 7−85, 8−90).


This standard specifies the emission and atomic absorption methods flaming photometry determination of sodium, potassium and calcium (at a mass proportion of each from 5·10% to 5·10%) in rare earth metals and their oxides (except cerium and its dioxide) and calcium (5·10% 1·10%) in the lanthanum, praseodymium, neodymium, Samaria, europium, gadolinium and their oxides.

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 23862.0−79.

2. APPARATUS, REAGENTS AND SOLUTIONS

Setup for the excitation and recorded emission spectra, comprising a burner-atomizer, providing a laminar flame, monochromator, designed for producing monochromatic radiation in the wavelength range from 400 to 800 nm. Photoelectronic multiplier (FEU-100), photoelectron attachment (type FEP-4).

Spectrophotometer Perkin-Elmer 300 or SFP-4A.

Lamp hollow cathode (LPK) for sodium lamp, or high frequency type VSB-2 on sodium.

Lamp hollow cathode (TIC) on the potassium lamp or a high frequency type VSB-2 on potassium.

Lamp hollow cathode (LPK) to calcium.

Pressure gauges according to GOST 2405−88.

Flowmeter type RS-3A.

High voltage stabilizer, VS-22 (B5−2P).

A high resistance potentiometer EPP-60M3.

Oxygen in cylinders with reducer according to GOST 13861−89.

Hydrogen in cylinders with reducer according to GOST 13861−89.

Ethyl alcohol according to GOST 17299−78.

Medical absorbent cotton wool GOST 5556−81.

Volumetric flasks with a capacity of 50 and 1000 cm.

Glasses chemical glass with a capacity of 50, 100 cm.

Acetylene in cylinders for technical GOST 5457−75.

The water is deionized.

Sodium chloride according to GOST 4233−77, H. h

Potassium chloride according to GOST 4234−77, H. h

Calcium carbonate according to GOST 4530−76, H. h

Hydrochloric acid by the GOST 3118−77, H. h., diluted 1:1.

Standard sodium solution containing 1 mg/cmsodium: 2,542 g of sodium chloride, previously dried to constant weight at 100−110 °C, placed in a beaker with a capacity of 100 cm, is dissolved in 10 cmof hydrochloric acid diluted 1:1, transferred into a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water and mix.

Solutions of sodium (working) containing 5·10, 1·10, 2·10, 6·10and 1·10mg/cmsodium, prepare a serial dilution of a standard solution of sodium water.

Potassium standard solution containing 1 mg/cmpotassium: of 1.91 g of potassium chloride, previously dried to constant weight at 100−110 °C, placed in a beaker with a capacity of 100 cm, is dissolved in 10 cmof hydrochloric acid (1:1), transfer the solution into a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water and mix.

Solutions of potassium (workers) containing 5·10, 1·10, 2·10, 6·10and 1·10mg/cmpotassium and sodium, prepare a serial dilution of a standard solution of potassium with water is added to each working solution of potassium appropriate amounts of solutions of sodium.

The buffer solution containing 0.05 mg/cmpotassium: 95,5 mg of potassium chloride, previously dried to constant weight at a temperature of 100−120 °C, placed in a beaker with a capacity of 100 cm, moisten with water, dissolve in a minimum amount of water, transferred to a flask with a capacity of 1000 cm, adjusted to the mark with water and mix.

Standard solution of calcium, containing 1 mg/cmcalcium: 2,497 g of calcium carbonate, previously dried to constant weight at 100−110 °C, placed in a beaker with a capacity of 100 cm, moistened with water, poured 10 cmof hydrochloric acid (1:1) was dissolved. The solution from the beaker is transferred to a volumetric flask 1000 cm, adjusted to the mark with water, mix.

The solutions of calcium (working) containing 5·10, 1·10, 2·10, 5·10, 1·10mg/cmof calcium, prepare a serial dilution of a standard solution of calcium water.

Solutions II calcium (water) containing 2·10, 5·10, 1·10, 2·10, 5·10, 1·10, 2·10, 1·10mg/cmof calcium prepared by dilution of a standard solution of calcium water.

Solutions of calcium III (working) containing 1·10and 2.5·10, 5·10, 1·10and 2.5·10, 5·10, 1·10mg/cmcalcium, is prepared by appropriate dilution of aqueous solutions II calcium buffer solution in a ratio of 1:1.

All the original solutions, as well as the water used for their preparation, store in a plastic or quartz container.

Sec. 2. (Changed edition, Rev. N 1, 2).

3. ANALYSIS

3.1. A flame photometry

The method of emission of flaming photometry is based on the excitation of the emission spectrum of the samples in air-acetylene flame and photoelectric registration of the resonance lines of sodium, potassium and calcium.

The contents of sodium, potassium and calcium find a method of additives.

Allowed the use of an air-hydrogen flame for the determination of sodium and potassium and an oxygen-hydrogen flame for the determination of calcium in lanthanum, praseodymium, neodymium, Samaria, europium, gadolinium and their oxides. Calcium find a method of limiting solutions.

3.1.1. A portion of the sample weighing 1 g (in mass fraction of sodium, potassium, calcium from 5·10% to 5·10%) were placed in a glass with a capacity of 50 cm, moistened with water, stirred, poured 10 cmof hydrochloric acid, heated at 60−70 °C until complete dissolving, evaporated to a volume of 3−4 cm, cool. The solution from the beaker is transferred to a volumetric flask of 50 cm, adjusted to the mark with water, mix. Simultaneously, a solution of the reference experiment, carrying it through all the stages of the analysis.

To determine the calcium in an oxygen-hydrogen flame (when the mass fraction of calcium from 1·10% 1·10%) a portion of the sample weighing 0.5 g was placed in a beaker with a capacity of 50 cm, moistened with water, pour 2 cmof hydrochloric acid, heated at 60−70 °C until complete dissolving, evaporated to a volume of 1−2 cm, cool, add 5−10 cmof water. The solution was transferred to a volumetric flask with a capacity of 25 cm, adjusted to the mark with water. Simultaneously, a solution of the reference experiment, carrying it through all the stages and

analysis.

3.1.2. Three sample test portion weighing 2 grams (for the mass concentration of sodium, potassium, calcium from 5·10% to 5·10%) placed in glasses with a capacity of 50 cm, moisten with water, mix. In two cups of injected additives working solutions of sodium, potassium, calcium: first — about equal to the alleged content of the determined elements in the sample, in the second glass twice. The contents of the glasses poured 10 cmof hydrochloric acid, heated at 60−70 °C until complete dissolving, evaporated to a volume of 3−4 cm, cool. The solution was transferred to volumetric flask with a capacity of 50 cm, adjusted to the mark with water. Simultaneously, a solution of the reference experiment, carrying it through all the stages of the analysis.

To determine the calcium in an oxygen-hydrogen flame (at a mass fraction of 5·10% 1·10%) a portion of the sample weighing 1 g is placed in a beaker with a capacity of 50 cm, moistened with water, poured 5cmof hydrochloric acid, heated at 60−70 °C until complete dissolving, evaporated to a volume of 1−2 cm, cool, add 5−10 cmof water, transferred to a volumetric flask with a capacity of 25 cmand was adjusted to the mark with water. Simultaneously, a solution of the reference experiment, carrying it through all the stages and

analysis.

3.1.3. Excitation spectra

The sample solution, the control experience and working solutions sequentially (in the ascending order of the contents of the element) is introduced into the burner flame (in the determination of calcium in an oxygen-hydrogen flame used working solutions III). The procedure was repeated twice.

3.1.1−3.1.3. (Changed edition, Rev. N 1).

3.1.4. The air pressure of 1.7·10PA, the flow rate of acetylene 40−50 DM/h (recorded on a scale of rotameter PC — 3A). Sodium is determined by the wavelength of the analytical line 589,0−589,6 nm, calcium at 422,6 nm. The width of the input and output slits of the device for determination of sodium, potassium and calcium 0,03−0,04 mm.

In determining the designated element in the oxygen-hydrogen flame set a hydrogen pressure of 2·10PA, and then oxygen 2·10PA, with the help of rotameter is gradually fed into the burner hydrogen (flow rate ~of 0.003 m/h), at the exit of the burner lit the flame. Set the hydrogen flow or oxygen of 0.05−0.06 m/h Width input and output gaps of 0.03−0.04 mm. the voltage on the photomultiplier 500−1000 V. registrarme measure the peak height of the analytical line of the element.

(Changed edition, Rev. N 1, 2

).

3.2. The method of atomic absorption

The method of atomic absorption is based on the atomization of sample in air-acetylene flame and photoelectric registration of the absorption resonance lines of sodium, potassium and calcium.

The contents of sodium, potassium and calcium find a method of additives.

3.2.1. The decomposition of the sample and the excitation spectrum is carried out as specified in PP.3.1.1, 3.1.2, 3.1.3.

3.2.2. The analysis is carried out on the spectrophotometer Perkin-Elmer 300 spectrophotometer, SFP-4A with odnoschelevye nozzle 10 cm.

The width of the slit of the instrument, Perkin-Elmer for sodium and potassium of 0.3 mm calcium 1 mm.

The width of the slit of the instrument, SFP-4A for sodium and potassium 0.040 mm, for calcium 0,080 mm.

Air consumption 16 DM/min flow rate of acetylene 3.3 DM/min.

Take readings of the digital voltmeter or milliammeter values (optical densities) at the wavelength of the analytical line of the designated element (see p.3.1.3).

4. PROCESSING OF THE RESULTS

4.1. Mass fraction of impurities determined in the sample in the range of 5·10-5·10%, mass fraction of calcium in the determination of his oxygen-hydrogen flame find by the method of limiting solutions. The concentration of the element in one of the working solutions should be less, and in another more than in the sample.

Mass fraction of sodium, potassium, calcium () in percent is calculated by the formula

,

where and  — the content of the element in the working solution, mg/cm();

, ,  — average values of peak height or optical density of the analytical lines of the designated element in the sample and working solutions, respectively;

 — the weight of the portion of the sample, g;

 — the volume of the analyzed solution, cm.

The result of the analysis taking the arithmetic mean of two parallel definitions, drawn from separate batches.

(Changed edition, Rev. N 1,

2).

4.2. Mass fraction of sodium, potassium, calcium in the sample (in the range of 5·10-5·10%) find by the method of additions.

Mass fraction of sodium, potassium, calcium () in percent is defined as the arithmetical average of the results of (, ) computed for the two additives:

; ; ,

where and  — the values of the first and second supplements of the element, %;

and  — mass fraction of the element calculated by the first and second additives, respectively, %;

, ,  — the values of peak height or optical density of the element for the sample, the sample with the first additive and the sample with the second additive, respectively.

4.3. Discrepancies in the results of two parallel determinations or the results of the two tests should not exceed the values permitted discrepancies listed in the table.

(Changed edition, Rev. N 1).