GOST 3240.2-76
GOST 3240.2−76 magnesium Alloys. Methods for determination of manganese (Change No. 1)
GOST 3240.2−76
Group B59
INTERSTATE STANDARD
MAGNESIUM ALLOYS
Methods for determination of manganese
Magnesium alloys.
Methods for determination of manganese
ISS 77.120.20
AXTU 1709
Date of introduction 1978−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of aviation industry of the USSR
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. REPLACE GOST 3240−56 in part of sec. V
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
The number of the paragraph, subparagraph |
| GOST 8.315−97 |
2.5, 3.5 |
| GOST 195−77 |
3.2 |
| GOST 804−93 |
4.2 |
| GOST 1277−75 |
2.2 |
| GOST 3118−77 |
4.2 |
| GOST 3240.0−76 |
1.1 |
| GOST 4197−74 |
2.2, 3.2 |
| GOST 4201−79 |
2.2 |
| GOST 4204−77 |
2.2, 3.2 |
| GOST 4233−77 |
2.2 |
| GOST 4328−77 |
2.2 |
| GOST 4461−77 |
2.2, 3.2, 4.2 |
| GOST 5457−75 |
4.2 |
| GOST 6008−90 |
4.2 |
| GOST 6552−80 |
2.2 |
| GOST 10929−76 |
3.2 |
| GOST 20478−75 |
2.2 |
| GOST 20490−75 |
2.2, 3.2 |
| GOST 25086−87 |
2.5, 3.5 |
5. Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)
6. EDITION with Change No. 1, approved in June 1987 (IUS 11−87)
This standard specifies the titrimetric method for the determination of manganese (at a mass fraction of manganese from 0.2 to 3%), a photometric method for the determination of manganese (at a mass fraction of manganese from 0.01 to 0.2%) and atomic absorption method for the determination of manganese (at a mass fraction of manganese from 0.01 to 3%).
(Changed edition, Rev. N 1).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 3240.0.
2. TITRIMETRIC METHOD FOR DETERMINATION OF MANGANESE CONTENT
2.1. The essence of the method
The method is based on oxidation of manganese neccersarily ammonium in the presence of a catalyst to pneumococcal condition and the titration solution arsenite-nitrite mixture.
(Changed edition, Rev. N 1).
2.2. Apparatus, reagents and solutions
Sulfuric acid according to GOST 4204, and diluted 1:1, 1:2 and 1:5.
Nitric acid according to GOST 4461.
Orthophosphoric acid according to GOST 6552.
A mixture of acids, is prepared as follows: to 600 cmof sulphuric acid, diluted 1:5, add 250 cm
of nitric acid, 125 cm
of phosphoric acid and mix thoroughly.
Silver nitrate according to GOST 1277, 0.01 M solution prepared as follows: 1.7 g of silver nitrate dissolved in 1000 cmof water and stirred.
Sodium atomistically according to GOST 4197.
Ammonium neccersarily according to GOST 20478, 10 and 25% solution.
Sodium chloride according to GOST 4233, 1% solution.
Sodium hydroxide according to GOST 4328, 5% solution.
Potassium permanganate according to GOST 20490, 0.05 M solution.
Sodium carbonate acidic, GOST 4201.
The mixture arsenite-nitrite; titrated solution; prepared as follows: 1.3 g of arsenious anhydride are dissolved in 20 cmof sodium hydroxide solution, diluted with water to 100−150 cm
and neutralized by litmus paper with sulfuric acid diluted 1:1 by introducing 0.5−1 cm
in its excess, which is neutralized with sodium carbonate acidic by litmus paper, and then to the solution was added 0.85 g of sodium attestatio, dilute with water to 1000 cm
and mixed.
Solution arsenite-nitrite mixture stored in a dark bottle closed with a rubber stopper with gorkaltseva tube.
Caption arsenite-nitrite mixture set to 0.05 M solution of potassium permanganate. In a flask with a capacity of 250 cm30 cm pour
mixture of acids, add 50 cm
of water, 2 cm
of a solution of silver nitrate and 10 cm
of a 10% solution of ammonium naternicola. The mixture was boiled for 1 min After cooling from the burette pour 20,0−25,0 cm
to 0.05 M solution potassium permanganate, 5 cm
1% sodium chloride solution and 10 cm
of sulphuric acid, diluted 1:2, titrated by a solution arsenite-nitrite mixture to obtain a pale pink colouration. Before the end of the titration arsenite-nitrite mixture was added dropwise with a spacing no
mi 5−10 s
2.3. Analysis
A portion of the alloy take, depending on the mass fraction of manganese in amounts given in table.1.
Table 1
| Mass fraction of manganese, % |
The weight of the portion of the alloy, g |
| To 0.5 |
1 |
| SV. 0,5 |
0,25 |
The sample is placed in a conical flask with a capacity of 250 cm, flow 10 cm
of water and in small portions 30 cm
of the mixture of acids. After the cessation of the violent reaction of the inner wall of the flask is washed with small amount of water and the solution is heated on a stove above 80 °C until complete dissolution of the alloy. Wash the walls of the bulb 50 cm
of water, introducing 10 cm
of a solution of silver nitrate, 15 cm
naternicola of ammonia, heated to boiling and boiled for 1−2 min. the flask with the solution is removed from the plate, careful rotation and remove remaining on the walls of the flask oxygen, is cooled to 15−20 °C, add 10 cm
sodium chloride solution, 10 cm
of sulphuric acid diluted 1:1 and titrated with a solution arsenite-nitrite mixture until the disappearance of the pink colors
I.
2.4. Processing of the results
2.4.1. Mass fraction of manganese () in percent is calculated by the formula
where — the volume arsenite-nitrite solution consumed for titration, cm
;
— the titer of arsenious anhydride, expressed in grams of manganese per milliliter;
— the weight of the portion of alloy,
2.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.2.
Table 2
| Mass fraction of manganese, % |
The absolute allowable difference, % |
| From 0.2 to 0.5 |
0,015 |
| SV. 0,5 «1,0 |
0,05 |
| «Of 1.0» to 3.0 |
0,1 |
2.5. Control of measurement accuracy
Control the accuracy of measuring the mass fraction of manganese from 0.2 to 3.0% is carried out using the State standard sample GSO 3363.
In addition, use the national standard samples of magnesium alloys, newly issued, as well as industry standard samples and standard samples of the enterprise of magnesium alloys, issued in accordance with GOST 8.315. Accuracy control measurement is carried out in accordance with GOST 25086.
Allowed to control the accuracy of measuring the mass fraction of manganese, using addition method.
(Changed edition, Rev. N 1).
3. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF MANGANESE CONTENT
3.1. The essence of the method
The method is based on the oxidation of divalent manganese to pneumococcal hodnoceni potassium measurement of optical density of the resulting permanganate-ion at 
3.2. Apparatus, reagents and solutions
The type СФ4А spectrophotometer or photoelectrocolorimeter types FEK-56, PEC-60.
Sulfuric acid according to GOST 4204, diluted 1:3.
Nitric acid according to GOST 4461, does not contain oxides of nitrogen.
For exemption from nitrogen oxides acid is boiled or passed through it a current of carbon dioxide.
Potassium cognately.
Distilled water, containing reductive substances; prepared as follows: 1000 cmof distilled water acidified with 10 cm
of sulphuric acid, bring to the boil, add a few crystals of potassium jednolitego and boiled for 10 min.
Potassium permanganate according to GOST 20490.
Sodium sanitarily according to GOST 195.
Hydrogen peroxide according to GOST 10929, 30% solution.
Sodium atomistically according to GOST 4197, 2% solution.
Standard solutions of manganese.
Solution A, prepared as follows: in a tall glass with a capacity of 400 cmcontaining 200 cm
of water, dissolve 2,8770 g of potassium permanganate, added 40 cm
of sulfuric acid and potassium permanganate restore with a few crystals semitecolo sodium or hydrogen peroxide. The solution was boiled to remove the excess of sulfur dioxide or of hydrogen peroxide, cooled, transferred into a measuring flask with volume capacity of 1000 cm
, is diluted to the mark with water and mix.
1 cmof the solution contains 1 mg of manganese.
Solution B is prepared as follows: 100 cmof solution A is taken in a measuring flask with volume capacity of 1000 cm
, is diluted to the mark with water and mix.
1 cmof a solution contains 0.1 mg Marg
ANCA.
3.3. Analysis
3.3.1. A portion of the alloy take, depending on the mass fraction of manganese in amounts given in table.3.
Table 3
| Mass fraction of manganese, % | The weight of the portion of the alloy, g | The quantity of sulfuric acid, see | |
| to dissolve |
for the reference experiment | ||
| From 0.01 to 0.05 |
1 |
25 |
5 |
| SV. Of 0.05 «to 0.2 |
0,5 |
20 |
0 |
The sample of alloy is placed in a flask with a capacity of 250 cm, adding 10 cm
of water and then small portions of sulfuric acid, the amount of which are shown in table.3, and the beaker cover watch glass. As soon as the dissolution is over, add 25 cm
of a solution of nitric acid and boil for a few minutes. The resulting solutions are diluted with water to 60 cm
, bring to the boil and add 0.5 g of potassium Odnokolenko, then boil for 5 minutes and leave the solution in a hot condition (about 98 °C) for 15 min. After cooling, the solutions were poured into a volumetric flask with a capacity of 100 cm
and dilute to the mark with water containing no reducing agents. At the same time spend control experience.
The platinum Cup was placed 25 cmof nitric acid and sulfuric acid in accordance with the table.3 and evaporated to dryness the contents of the Cup. Then dissolve the residue in small amount of hot water, poured the solution into a flask with a capacity of 250 cm
, dilute with water to 40 cm
, add 20 cm
of sulfuric acid and further analysis are as indicated above in the analysis of the sample.
The optical density of test solution (a) and solution of the control experiment (
) in the respective cuvettes are measured at 545 nm, using as comparisons the water. Then, in the test solution and the control solution experience injected dropwise a solution of sodium attestatio to bleaching and repeat the measurement of the optical density of test solution (a
) and solution control practices (
). Solution comparison is water.
The optical density of test solution (a) is calculated according to the formula
3.3.2. Construction of calibration curve
3.3.2.1. Preparation of the compensating solution.
The platinum Cup is placed 20 cm innitric acid and evaporated to dryness. The Cup is washed with a small amount of hot water, poured the solution into a measuring flask with a capacity of 250 cm
, was diluted to 40 cm
of water and add 15 cm
of sulfuric acid and 5 cm
of nitric acid.
In six volumetric flasks with a capacity of 250 cmis introduced 1,0; 2,0; 5,0; 10,0; 15,0 and 20.0 cm
of a solution, which corresponds to 0,0001; 0,0002; 0,0005; 0,0010; and 0,0015 0,0020 g of manganese and dilute the contents of flasks with water up to 40 cm
, then add 15 cm
of sulphuric acid, to 25 cm
of nitric acid and further analysis are as indicated in claim 3.3, using as a reference the experience of a compensating solution.
On the found values of optical density calibration build Gras
FIC.
3.1−3.3. (Changed edition, Rev. N 1).
3.4. Processing of the results
3.4.1. Mass fraction of manganese () in percent is calculated by the formula
where is the number of manganese was found in the calibration schedule g;
— the weight of the portion of alloy,
3.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.4.
Table 4
| Mass fraction of manganese, % |
The absolute allowable difference, % |
| From 0.01 to 0.03 |
0,003 |
| SV. Of 0.03 «to 0.05 |
0,005 |
| «0,05» 0,10 |
0,01 |
| «To 0.10» to 0.20 |
0,03 |
3.1−3.4. (Changed edition, Rev. N 1).
3.5. Control of measurement accuracy
Control the accuracy of measuring the mass fraction of manganese from 0.01 to 0.2% is carried out using the State standard sample GSO 3363.
In addition, use the national standard samples of magnesium alloys, newly issued, as well as industry standard samples and standard samples of the enterprise of magnesium alloys, issued in accordance with GOST 8.315. Accuracy control measurement is carried out in accordance with GOST 25086.
Allowed to control the accuracy of measuring the mass fraction of manganese, using addition method.
(Added, Rev. N 1).
4. ATOMIC ABSORPTION METHOD FOR DETERMINATION OF MANGANESE CONTENT
4.1. The essence of the method
The method is based on dissolving the samples in hydrochloric acid in the presence of nitric acid and subsequent measurement of the atomic absorption of manganese at a wavelength of 279.5 nm in the flame acetylene-air.
4.2. Apparatus, reagents and solutions
Atomic absorption spectrophotometer with all accessories.
Acetylene in cylinders GOST 5457.
Hydrochloric acid according to GOST 3118, diluted 1:1.
Nitric acid according to GOST 4461, diluted 1:1.
Manganese metal according to GOST 6008 in the form of chips.
Standard solutions of manganese
Solution a: 1 g of manganese dissolved by heating in 50 cmof a solution of nitric acid. The solution was heated to remove oxides, cooled, 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 1 mg of manganese.
Solution B: 50 cmsolution And transferred to a volumetric flask with a capacity of 500 cm
, is diluted to the mark with water and mix.
1 cmof a solution contains 0.1 mg of manganese.
Magnesium metal in ingots according to GOST 804 in the form of chips with a manganese content of not more than 0.0005%.
A solution of magnesium 50 g/DM: 50 g of magnesium carefully dissolved in 800 cm
of hydrochloric acid diluted 1:1. The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM
, made up to the mark with water and paramashiva
yut.
4.3. Analysis
4.3.1. A sample of alloy weighing 1 g is placed in a beaker with a capacity of 300 cm, is dissolved in 30 cm
of hydrochloric acid, add 5−10 drops of nitric acid and boil to remove oxides of nitrogen. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water, mix and carry out the dilutions in accordance with table.5.
Table 5
| Mass fraction of manganese, % |
Dilution is the solution, cm |
| From 0.01 to 0.16 |
- |
| SV. 0,16 «1,4 |
10/100 |
| «1,4» 3,0 |
5/100 |
Parallel to the sample conduct analysis of control experience.
Measure the atomic absorption of manganese in the sample solution, the solution control experience and solutions to build the calibration curve in atomic absorption spectrophotometer against water at a wavelength of 279.5 nm in the flame acetylene-air.
The concentration of manganese in the sample solution and the reference experiment is determined by the calibration schedule.
4.3.2. To construct the calibration curve in mass fraction of manganese from 0.01 to 0.16% in a series of volumetric flasks with a capacity of 100 cmis administered at 20 cm
of a solution of magnesium, 0; 1,0; 2,0; 4,0; 6,0; 8,0; 10,0; 12,0; 14,0 and 16.0 cm
of a solution that fits 0; 0,1; 0,2; 0,4; 0,6; 0,8; 1,0; 1,2; 1,4 and 1.6 mg manganese. When the mass fraction of manganese from 0.16 to 1.4% in a series of volumetric flasks with a capacity of 100 cm
are 2 cm
of a solution of magnesium 0; 1,6; 2,0; 4,0; 6,0; 8,0; 10,0; 12,0 and 14.0 cm
solution B, which corresponds to 0; 0,16; 0,20; 0,40; 0,60; 0,80; 1,00; 1,20 and 1.40 mg of manganese. When the mass fraction of manganese from 1.4 to 3.0% in a series of volumetric flasks with a capacity of 100 cm
inject 1 cm
of solution of magnesium, 0; 7,0; 8,0; 10,0; 12,0; 14,0 and 16.0 cm
of a solution that fits 0; 0,70; 0,80; 1,00; 1,20; 1,40 and 1.60 mg of manganese. Solutions for calibration topped up to the mark with water, mix and measure the atomic absorption of manganese according to claim
From the obtained values of atomic absorption solutions containing a standard solution, subtract the value of atomic absorption of a solution containing a standard solution, and the obtained values of atomic absorption and corresponding content of manganese build the calibration graph
IR.
4.4. Processing of the results
4.4.1. Mass fraction of manganese () in percent is calculated by the formula
where is the mass of manganese in the sample solution found by the calibration schedule g;
— the mass of manganese in solution in the reference experiment, was found in the calibration schedule g;
— the weight of the portion of sample taken for spectrophotometry,
4.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.6.
Table 6
| Mass fraction of manganese, % |
The absolute allowable difference, % |
| From 0.01 to 0.03 |
0,001 |
| SV. Of 0.03 «to 0.08 |
0,002 |
| «Of 0.08» to 0.20 |
0,005 |
| «0,2» 0,5 |
0,012 |
| «0,5» 1,2 |
0,03 |
| «1,2» 3,0 |
0,07 |
4.1−4.4. (Changed edition, Rev. N 1).
4.5. Control of measurement accuracy
Control the accuracy of measuring the mass fraction of manganese according to claim 2.5.
(Added, Rev. N 1).
