GOST 23862.36-79
GOST 23862.36−79 Rare-earth metals and their oxides. Methods for determination of chlorine (with Amendments No. 1, 2)
GOST 23862.36−79
Group B59
INTERSTATE STANDARD
RARE EARTH METALS AND THEIR OXIDES
Methods of determination of chlorine
Rare-earth metals and their oxides. Methods of determination of chlorine
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 3989 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 turbidimetric method for the determination of chlorine (5·10% to 2.5·10
%) in the lanthanum, neodymium, Samaria, europium, gadolinium, dysprosium, holmium, yttria and their oxides, turbidimetric method for the determination of chlorine (from 1·10
% to 5·10
%) with pre-Stripping in rare-earth metals and their oxides (except cerium and its dioxide) and the polarographic method for the determination of chlorine (from 2·10
— 1.0%) in rare-earth metals and their oxides (except cerium and its dioxide).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 23862.0−79.
2. TURBIDIMETRIC METHOD OF DETERMINATION OF CHLORINE
The method is based on turbidimetric determination of chloride in nitric acid medium by solo silver chloride.
2.1. Apparatus, reagents and solutions
Photoelectrocolorimeter FEK-56 or similar device.
Bath water.
Muffle furnace with thermostat providing temperatures up to 500 °C.
A glass with a capacity of 100 cm.
Volumetric flasks with a capacity of 50 and 1000 cm.
Glass hour.
The filter «white» or «blue» tape.
Nitric acid of high purity according to GOST 11125−84 (CC balance): in a flask installation for the distillation of acid is administered 1,2 DMnitric acid. Distilled from the flask 1,1 DM
acid at a speed of not more than 0.4 PM
/h. part of the residue is diluted with distilled water in a ratio of 1:1 and 1:19.
Silver nitrate according to GOST 1277−75, H. h, solution with a concentration of 2 g/DM.
Sodium chloride according to GOST 4233−77, H. h
A standard solution of chlorine (spare) containing 1 mg/cmchlorine: the weight of sodium chloride weight of 1,648 g, previously calcined to constant weight at a temperature of 500 °C, dissolved in water, transferred to a measuring flask with volume capacity of 1000 cm
and top up with water to the mark.
A solution of chlorine (work) containing 10 ug/cmchlorine, prepared on the day of use by dilution of a standard (fallback) solution water 100 times.
(Changed edition, Rev. N 1
).
2.2. Analysis
2.2.1. A portion of the sample weighing 0.1 g was placed in a beaker, moisten with water, mix and add 10 cmof nitric acid (1:1). Beaker cover watch glass, put on a boiling water bath and kept for 15−20 min After dissolving the sample contents of the Cup is transferred to a volumetric flask with a capacity of 50 cm
and dilute to the mark with water. If the sample is not dissolved completely, the solution was filtered through a dense filter, washed with nitric acid (1:1) until negative reaction for chloride ion. 10 cm
of the resulting solution transferred to a volumetric flask with a capacity of 50 cm
add 30 cm
of nitric acid (1:19), then add 2cm
of a solution of silver nitrate and the volume was adjusted to the mark with water. The solution is stirred and kept for 20 min in a dark place, then measure the optical density on the photoelectrocolorimeter at
Simultaneously with the analysis of the sample through all stages of the analysis carried out control experience in chemicals. The obtained value of optical density is subtracted from the value of optical density of test solution. Optical density of the solution in the reference experiment shall not exceed 0.05 otherwise, you have to change the reagents.
Find the mass of chlorine in the calibration schedule
.
2.2.2. Construction of calibration curve
In a volumetric flask with a capacity of 50 cmimpose 1,0; 2,0; 3,0; 4,0; 5,0 cm
standard (working) solution of chlorine (containing 10 ug/cm
chlorine). To each flask add 40 cm
of nitric acid, diluted 1:19, 2 cm
of a solution of silver nitrate and adjusted to the mark with nitric acid, diluted 1:19. The solutions were mixed and incubated in the dark for 20 min. In one of the flasks is introduced all the reagents except chlorine (zero solution). The optical density of solutions measured on photoelectrocolorimeter at
The value of the optical density of each point of the graph graduirovochnyh calculated as the arithmetic mean result of five parallel measurements.
The optical density of the zero solution should not exceed 0.05. Otherwise, change the reagents. The value of optical density of the zero solution is subtracted from the values of optical densities of standard solutions.
According to the obtained results build a calibration curve, causing the y-axis the value of the optical density of the solution, and on the x — axis is the mass in milligrams of chlorine. Individual points chart check at least once per month.
2.2.1,
2.3. Processing of the results
2.3.1. Mass fraction of chlorine (the) percentage is calculated by the formula
where is the mass of chlorine was found in the calibration graphics mg;
— the weight of the portion of the sample,
2.3.2. Discrepancies in the results of two parallel determinations or the results of the two tests should not exceed values of allowable differences specified in table.1.
Table 1
| Mass fraction of chlorine, % |
Allowable difference, % |
5·10 |
2·10 |
2,5·10 |
5·10 |
3. TURBIDIMETRIC METHOD FOR THE DETERMINATION OF CHLORINE AND STRIPPING
The method is based on turbidimetric determination of chlorine solu chloride of silver nitrate in the environment after distilling off chlorine pyrohydrolysis.
3.1. Apparatus, reagents and solutions
Installation for pyrohydrolysis according to GOST 23862.32−79.
Photoelectrocolorimeter FEK-56 or similar device.
Muffle furnace with thermostat providing temperatures up to 900 °C.
The gaseous nitrogen according to GOST 9293−74 or oxygen gas GOST 5583−78.
Volumetric flasks with a capacity of 50 and 1000 cm.
Quartz boats with a length of 70 mm and a width of 10 mm, calcined at a temperature of 1000−1050 °C in a current of steam for 30−40 min.
The hook is made of quartz sticks with a diameter of 6 mm and a length of 500 mm.
Nitric acid of high purity according to GOST 11125−84 (CC balance): in a flask installation for the distillation of acid is administered 1,2 DMnitric acid. Distilled from the flask 1,1 DM
acid at a speed of not more than 0.4 PM
/h. part of the residue is diluted with distilled water in the ratio 1:1, 1:4 and 1:19.
Silver nitrate according to GOST 1277−75, H. h, 0,2% solution.
Sodium chloride according to GOST 4233−77, H. h
A standard solution of chlorine (spare) containing 1 mg/cmchlorine: the weight of sodium chloride weight of 1,648 g, calcined to constant weight at 500 °C, dissolved in water, transferred into a measuring flask with volume capacity of 1000 cm
, adjusted to the mark with water and mix.
A solution of chlorine (work) containing 10 ug/cmchlorine, prepared on the day of use by dilution of a backup solution with water to 100 times.
The water is deionized.
(Changed edition, Rev. N 1)
.
3.2. Preparation for assay
3.2.1. Installation for pyrohydrolysis ready, checking for a faulty furnace, electric, insulation of the live wires for grounding. Include a hot plate for heating water in the steam generator to boil. Include the oven by pressing the start button. Regulate the flow of nitrogen (or oxygen), setting a rate of 1−2 bubbles per second. A bubbler immersed in a glass with a capacity of 100 cm, containing 10 cm
of nitric acid, diluted 1:4. The furnace is heated to 600 °C.
3.3. Analysis
3.3.1. A portion of the sample mass of 0.1−1 g (depending on chlorine content) was placed in a quartz boat evenly, moisten with a few drops of water, placed in a tube of the unit to pyrohydrolysis and quickly stoppered. Increase the oven temperature to 1000−1050 °C and at this temperature, continue pyrohydrolysis 15−20 min until volume of the solution in the receiver 45−47 cm(for analysis of oxides of REE flow of nitrogen, the analysis of the metal — oxygen). Thereafter, the furnace shut off, remove the boat. The solution from the receiver is transferred into a measuring flask with a capacity of 50 cm
, add 2 cm
of concentrated nitric acid, 2cm
of a solution of silver nitrate, the volume was adjusted to the mark with water, mix and leave to stand for 20 min in a dark place. After 20 min, measure the optical density of the test solution on a photoelectrocolorimeter at
Find the mass of chlorine in the calibration schedule.
3.3.2. Construction of calibration curve
In a volumetric flask with a capacity of 50 cmimpose 1,0; 2,0; 3,0; 4,0; 5,0; 6,0; 7,0; 8,0; 9,0 and 10.0 cm
of the working solution of chlorine. In each flask pour 40 cm
of nitric acid 1:19, 2 cm
of a solution of silver nitrate, the volume was adjusted to the mark with the same acid, stirred, allowed to stand for 20 min in the dark. In one of the flasks is introduced all the reagents except chlorine solution (zero solution). The optical density of solutions measured on photoelectrocolorimeter at
The value of the optical density of each point of calibration curve is calculated as the simple average result of five parallel measurements.
According to the obtained results build a calibration curve, causing the y-axis the value of the optical density of the solution, and on the x — axis is the mass in milligrams of chlorine. Individual points chart check at least once per month.
(Changed edition, Rev. N 1).
3.4. Processing of the results
3.4.1. Mass fraction of chlorine (the) percentage is calculated by the formula
________________
* Formula conforms to the original. — Note the manufacturer’s database.
where is the mass of chlorine was found in the calibration graphics mg;
— the weight of the portion of the sample,
3.4.2. Discrepancies in the results of two parallel definitions and results of the two tests should not exceed values of allowable differences specified in table.2.
Table 2
| Mass fraction of chlorine, % |
Allowable difference, % |
1·10 |
5·10 |
5·10 |
1·10 |
POLAROGRAPHIC METHOD FOR THE DETERMINATION OF CHLORINE
The method is based on the polarographic determination of chlorine in the nitric-acid solution at a potential of half-wave peak recovery of chloride ions of about minus 0.05 V relative to the mercury anode. Cerium ions should be absent.
4.1. Apparatus, reagents and solutions
Polarograph AC-PPT-1 or PU-1 or similar device.
The polarographic sensor with a mercury drop electrode is a cathode and bottom mercury anode. The rate of flow of mercury to about 10 drops in 15 seconds.
Bath water.
Muffle furnace with thermostat, providing a temperature of 450−500 °C.
Volumetric flasks with a capacity of 50, 100, and 1000 cm.
Glasses glass with a capacity of 50 cm.
Watch-glasses.
The water is deionized.
Nitric acid of high purity according to GOST 11125−84 or nitric acid according to GOST 9336−75, H. h, and further purified by Stripping in a quartz apparatus (distilled 2/3 of the original amount of acid is used, the VAT residue), diluted 1:1.
Potassium nitrate according to GOST 4217−77, H. h, solution concentration 101 g/DM.
Sodium chloride according to GOST 4233−77.
A standard solution of chlorine (spare) containing 1 mg/cmchlorine, is prepared as follows: a sample of sodium chloride by weight of 1,648 g, previously calcined at 500 °C, dissolved in water, transferred into a measuring flask with volume capacity of 1000 cm
, adjusted to the mark with water and mix.
Chloride solution containing 10 ug/cmchlorine, prepared on the day of use by dilution of a standard (fallback) solution water 100 times.
(Changed edition, Rev. N 1, 2).
4.2. Analysis
4.2.1. Definition of chlorine from the 2·10% to 5·10
%
Two sample test portion of 0.5 g is placed in glasses with a capacity of 50 cm, moistened with water, in one of the glasses introduce a solution of chlorides containing 10 µg/cm
chlorides, so that the mass of the introduced chlorides of 2−3 times the estimated weight of the chlorides in the sample. Then add 5 cm
of nitric acid, cover glasses, watch glasses, and dissolve the sample with moderate heat (40−50 °C) water bath.
The solutions were cooled, transferred to volumetric flasks with a capacity of 50 cm, add 20 cm
of a solution of nitrate of potassium, the volume was adjusted to the mark with water and mix.
Solutions polarography in the range of plus 0.2 and minus 0.2 V. the peak Potential is about minus 0.50 per relative to the bottom of mercury.
Simultaneously with the analysis of the sample carried through all stages of the analysis of the audit experience of the reagents
.
4.2.2. Definition of chlorine from 5·10% to 1.0%
A portion of the sample, 0.1 g placed in a beaker with a capacity of 50 cm, moisten with water, add 5 cm
of nitric acid, cover the beaker watch glass and dissolve with a moderate heat (40−50 °C) water bath.
The solution was cooled, transferred to a volumetric flask with a capacity of 50 cm, add 20 cm
of a solution of potassium nitrate, the volume was adjusted to the mark with water, mix.
Solution polarography in the range of plus 0.2 and minus 0.2 V. the peak Potential of about minus 0.05 V relative To the bottom of mercury.
At the same time through all stages of the analysis carried out control experience in chemicals. The value of the peak height of the voltammetric curve in the reference experiment is subtracted from the value of the peak height of the sample analyzed. Analysis of each sample is carried out in two parallel batches.
4.2.3. Construction of calibration curve
In a volumetric flask with a capacity of 100 cmpour 0; 0,1; 0,2; 0,5; 1,0; 1,5; 2,0 cm
standard (spare) solution of chlorides, which corresponds to 0; 0,1; 0,2; 0,5; 1,0; 1,5 and 2.0 mg of chlorine. Then add 10 cm
of nitric acid (1:1) and 40 cm
of a solution of nitrate of potassium, the volume was adjusted to the mark with water, mix and polarografic the resulting solutions as described in section
of solution, and on the y — axis the corresponding values of the heights of the peaks of the voltammetric curves of solutions of chlorides minus the value of the wave height of the zero solution.
(Changed edition, Rev. N 1, 2).
4.3. Processing of the results
4.3.1. By the method of additives (mass fraction of chlorine from 2·10% to 5·10
%) mass fraction of chlorine (the
) percentage is calculated by the formula
where ,
,
are the height of the peaks of the voltammetric curves of the samples, the sample with additive and control experience, respectively, cm;
— the mass of chlorides introduced into the test solution, mg;
— the weight of the portion of the sample,
4.3.2. According to the method of calibration curve (mass fraction of chlorine 5·10 — 1%) mass fraction of chlorine (the
) percentage is calculated by the formula
where is the mass of chloride in the test solution found on the schedule, mcg;
— the weight of the portion of the sample,
4.3.3. Discrepancies in the results of two parallel determinations or the results of the two tests should not exceed values of allowable differences specified in table.3.
Table 3
| Mass fraction of chlorine, % |
Allowable difference, % |
2·10 |
8·10 |
1·10 |
3·10 |
5·10 |
1,4·10 |
7·10 |
2·10 |
4·10 |
8·10 |
| 1,0 |
2·10 |
