GOST 1953.14-79
GOST 1953.14−79 Bronze tin. Method for the determination of magnesium (with Amendments No. 1, 2)
GOST 1953.14−79
Group B59
INTERSTATE STANDARD
BRONZE TIN
Methods for determination of magnesium
Tin bronze.
Methods for the determination of magnesium
AXTU 1709
Date of introduction 1981−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. REPLACE GOST 1953.14−76
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Section number, paragraph, sub-paragraph |
| GOST 8.315−97 |
4.4; 5.4.4 |
| GOST 613−79 |
Chapeau |
| GOST 614−97 |
Chapeau |
| GOST 804−93 |
5.2 |
| GOST 1953.1−79 |
1.1 |
| GOST 3118−77 |
2; 5.2 |
| GOST 3760−79 |
2 |
| GOST 3773−72 |
2 |
| GOST 4204−77 |
2 |
| GOST 4328−77 |
2 |
| GOST 4461−77 |
2; 5.2 |
| GOST 4526−75 |
2 |
| GOST 5456−79 |
2 |
| GOST 8864−71 |
2 |
| GOST 25086−87 |
1.1; 4.4; 5.4.4 |
5. Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)
6. EDITION with Amendments No. 1, 2 approved in February 1983, August 1990 (IUS 6−83, 11−90)
This standard sets the photometric method for the determination of magnesium (from 0.005% to 0.05%) and atomic absorption method for the determination of magnesium (0.001% to 0.05%) in tin bronze according to GOST GOST 613 and 614.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 with the Supplement according to claim 1.1 GOST 1953.1.
(Changed edition, Rev. N 1, 2).
2A. PHOTOMETRIC METHOD
The essence of the method
The method is based on the formation of magnesium in an alkaline medium with titanium yellow or Phenazo compounds red-violet and measuring the optical density of the colored solution.
Sec. 2A. (Added, Rev. N 2).
2. APPARATUS, REAGENTS AND SOLUTIONS
Photoelectrocolorimeter or spectrophotometer.
Nitric acid according to GOST 4461.
Sulfuric acid according to GOST 4204.
Hydrochloric acid according to GOST 3118 and diluted 1:1.
The mixture of acids to dissolve; prepared as follows: mix one part nitric and three parts hydrochloric acid.
Ammonia water according to GOST 3760.
Sodium hydroxide according to GOST 4328, solution 200 g/land 2 mol/DM
.
Ammonium chloride according to GOST 3773, solutions of 20 and 200 g/DM.
Hydroxylamine hydrochloric acid according to GOST 5456, solution 100 g/DM.
Gelatin solution 5 g/DM.
Sodium N, N-diethyldithiocarbamate 3-water according to GOST 8864, a solution of 50 g/DM.
Alum salesonline, a solution of 100 g/DMis prepared as follows: 10 g of alum was dissolved with heating in 70 cm
water and 1 cm
of concentrated sulfuric acid. The solution is diluted with water to 100 cm
.
Titanium yellow, a solution of 0.5 g/DM.
Magnesium oxide according to GOST 4526.
Standard solutions of magnesium. Solution A, prepared as follows: stands at 1.6584 g of magnesium oxide, previously calcined in a quartz crucible with (1000±50) °C for 1 h, dissolved in 10 cmof hydrochloric acid diluted 1:1. The solution was transferred to a volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix.
1 cmof the solution contains 0.001 g of magnesium.
Solution B is prepared as follows: 5 cmsolution And placed in a volumetric flask with a capacity of 500 cm
, made up to the mark with water and mix.
1 cmof solution B has the 0.00001 g of magnesium.
Phenazo, a solution of 0.05 g/DM2 mol/DM
solution of sodium hydroxide.
Sec. 2. (Changed edition, Rev. N 2).
3. ANALYSIS
3.1. A sample weighing 1 g is placed in a beaker with capacity of 500 cm, adding 25 cm
of the mixture of acids, cover with a watch glass and dissolved under heating. The solution is cool, add 150−200 cm
water, 1 cm
of solution gentoomaniac alum, 5 cm
of a solution of ammonium chloride (200 g/DM
) and ammonia before the transfer of copper in a soluble ammonia complex. Solution to precipitate the hydroxide is heated and kept for 30 min at 60 °C for coagulation of the precipitate. The precipitate was filtered off on a medium density filter and washed 8−10 times with a solution of ammonium chloride (20 g/DM
). The precipitate is discarded. The filtrate is evaporated to a volume of 250 cm
, cooled and neutralized with hydrochloric acid diluted 1:1, to pH 4−4,5 on the universal indicator paper. The solution was transferred to a volumetric flask with a capacity of 500 cm
and added with stirring 160 cm
solution of sodium diethyldithiocarbamate. The solution was diluted to the mark with water, mix thoroughly and leave for 4−5 hours for sedimentation of sludge (you can leave overnight). The supernatant solution was filtered in a dry conical flask using a dry dense dry funnel and filter, discarding first portion of filtrate (15−20 cm
) and rinsing them in a flask.
Aliquot part of the solution volume of 200 cmwhen the content of magnesium from 0.005% to 0.02%, and 100 cm
at the greater content of magnesium is placed in a beaker with a capacity of 250 cm
and is evaporated under low heat to a volume of 40−45 cm
, and then transferred to a volumetric flask with a capacity of 100 cm
, add 10 cm
of a solution of hydrochloric acid hydroxylamine, 5 cm
gelatin solution, 10 cm
of the solution, Pinazo or 5 cm
of a solution of Titan yellow, 20 cm
of sodium hydroxide solution (200 g/DM
), made up to the mark with water, mix and measure the optical density of the solution in cuvette with thickness of the absorbing layer of 5 cm at a photoelectrocolorimeter with a green colour filter or in a ditch with thickness of absorbing layer 1 cm on the spectrophotometer at 540 nm.
As a solution comparison solution is used in the reference experiment.
(Changed red
Ktsia, Rev. N 2).
3.2. Construction of calibration curve
In a volumetric flask with a capacity of 100 cmplaced 0; 1,0; 2,0; 4,0; 6,0; 8,0 and 10.0 cm
standard solution B magnesium, dilute with water to 50 cm
, add 10 cm
of a solution of hydrochloric acid hydroxylamine and further analysis is carried out as specified in clause 3.1.
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of magnesium (a) in percent is calculated by the formula
where the amount of magnesium was found in the calibration schedule g;
— the weight of the portion corresponding to aliquote part of the solution,
4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for
3), specified in the table.
| Mass fraction of magnesium, % |
|
|
| From 0.001 to 0.005 incl. |
0,0005 |
0,0007 |
| SV. Of 0.005 «to 0.02 « |
0,001 |
0,001 |
| «0,02» 0,05 « |
0,002 |
0,003 |
(Changed edition, Rev. N 2).
4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in the table.
4.4. Control of accuracy of analysis results is carried out by additives or by comparison of the results obtained by atomic absorption method, or by State standard samples of tin bronzes, re-approved by GOST 8.315, in accordance with GOST 25086.
4.3, 4.4. (Added, Rev. N 2).
5. ATOMIC ABSORPTION METHOD FOR DETERMINATION OF MAGNESIUM
5.1.The essence of the method
The method is based on measuring the absorption of light by atoms of magnesium, formed when the introduction of the analyzed solution in the flame acetylene-air.
5.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with a radiation source for magnesium.
Nitric acid according to GOST 4461 and diluted 1:1.
Hydrochloric acid according to GOST 3118.
A mixture of acids: nitric acid mixed with a salt in the ratio 1:3.
Magnesium GOST 804.
Standard solutions of magnesium.
Solution a: 0.1 g of magnesium was dissolved with heating in 10 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 1 DM
and topped to the mark with water.
1 cmof the solution contains 0.0001 g of magnesium.
Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm
and top up with water to the mark.
1 cmof solution B has the 0.00001 g of magnesium.
5.3. Analysis
5.3.1. The weight of bronze weighing 0.5 g was dissolved with heating in 10 cmof a mixture of acids. The solution was transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark.
Measured by atomic absorption in the flame acetylene-air at a wavelength of RUB 285.2 nm parallel to the calibration solutions.
5.3.2. Construction of calibration curve
In six of the seven volumetric flasks with a capacity of 100 cmis placed 1.0 and 5.0 cm
of a standard solution of magnesium B and 1.0; 1.5; 2.0 and 2.5 cm
of a solution of magnesium A. In all flasks are poured 10 cm
of the mixture of acids and add water to the mark.
Measure the atomic absorption of magnesium, as specified in clause
5.4. Processing of the results
5.4.1. Mass fraction of magnesium (a) in percent is calculated by the formula
where the magnesium concentration was found in the calibration schedule, g/cm
;
— the volume of the sample solution, cm
;
— the weight of the portion of the sample,
5.4.2. Discrepancies in the results of parallel definitions should not exceed the values permitted by the definition* (the rate of convergence for
3), specified in the table.
_______________
* The text matches the original. — Note the CODE.
5.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in the table.
5.4.4. Control the accuracy of the results of the analysis carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or by additives or by comparison of the results obtained by the photometric method according to GOST 25086.
5.4.5. Atomic absorption method is used in case of disagreement in assessing the quality of tin bronzes.
Sec. 5. (Added, Rev. N 2).
