GOST 2604.5-84
GOST 2604.5−84 alloy Cast iron. Methods for determination of manganese (Change No. 1)
GOST 2604.5−84
Group B09
INTERSTATE STANDARD
ALLOY CAST IRON
Methods for determination of manganese
Alloy cast iron. Methods for determination of manganese
ISS 77.080.10
AXTU 0809
Date of introduction 1985−01−01
The decision of the State Committee of USSR on standards as of January 27, 1984 N 357 date of introduction is established 01.01.85
Limitation of actions taken by Protocol No. 4−94 of the Interstate Council for standardization, Metrology and certification (ICS 4−93)
REPLACE GOST 2604.5−77
EDITION with Change No. 1, approved in April 1989 (IUS 7−89).
This standard sets the photometric method for the determination of manganese (at a mass fraction of from 0.10 to 2.0%), titrimetric method (with a mass fraction of from 0.20 to 5.0%), potentiometric method (with a mass fraction of from 2.0 to 25.0%) and atomic absorption method (with a mass fraction of from 0.10 to 5.0%) in the doped iron.
The standard corresponds to the international standard ISO 629−82 in part by the photometric method.
(Changed edition, Rev. N 1).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 28473−90.
1.2. The error analysis result (at p = 0.95) must not exceed given in table.2, when the following conditions are met:
the discrepancy between the results of two (three) parallel dimensions should not exceed (at p = 0.95) values are 
played in the standard sample, the value of the mass fraction of the element must not vary from certified more than acceptable (at a confidence level of 0.85) the value given in table.2.
If any of the above conditions, a second measurement of the mass fraction of manganese. If in repeated measurements the precision requirement of the results are not met, the results of the analysis recognize the incorrect measurements cease to identify and eliminate the causes of violation of the normal course of analysis.
The divergence of the two middle results of an analysis performed under different conditions (for example, when the control intralaboratory reproducibility) shall not exceed (at p = 0.95) values are given in table.2.
(Added, Rev. N 1).
2. PHOTOMETRIC METHOD
2.1.The essence of the method
The method is based on the oxidation of bivalent manganese to pneumococcal hodnoceni potassium sulfate or nitrate in the medium and measuring the optical density of the coloured complex at a wavelength of 545 nm.
The influence of iron can be eliminated by addition of phosphoric acid.
2.2. Apparatus, reagents and solutions
Spectrophotometer or photoelectrocolorimeter.
Hydrochloric acid by the GOST 3118−77.
Nitric acid GOST 4461−77 and diluted 1:1, 1:100.
Sulfuric acid GOST 4204−77 and diluted 1:4.
Orthophosphoric acid according to GOST 6552−80.
A mixture of acids: 750 cmwater gently with continuous stirring poured 150 cm
of sulfuric acid, cooled, poured 100 cm
of phosphoric acid, stirred and cooled.
Potassium cognately, a solution of 50 g/DM: jednolitego 50 g of potassium are dissolved in 800 cm
of nitric acid (1:1), the solution was cooled, top up with water to 1 DM
and stirred.
Potassium permanganate according to GOST 20490−75.
Hydrogen peroxide according to GOST 10929−76, a solution of 0.3 g/cm.
Carbonyl iron OS. h
Sodium atomistically according to GOST 4197−74, a solution of 1 g/cm.
Standard solutions of sulphate of manganese:
the solution And the mass concentration of 0.0002 g/cm: 0,5754 g of potassium permanganate recrystallized and air dried were placed in a glass with a capacity of 250 cm
, add 20 cm
of sulphuric acid (1:4) and gently, drop by drop, with stirring add hydrogen peroxide or hydrochloric acid to the bleaching solution. The solution was evaporated until beginning crystallization. Salt is dissolved by heating in 20−30 cm
of water, cooled, transferred to a volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix.
Solution B with a mass concentration of 0.0001 g/cm: 100 cm
standard solution And placed in a volumetric flask with a capacity of 200 cm
, made up to the mark with water and mix.
Water, not containing reducing agents: in a flask with a capacity of 2 DM1 DM pour
water, add dropwise sulfuric acid to a pH of 3 by universal indicator paper, heated to boiling, add a few crystals of potassium Odnokolenko, boil for 5−7 min and cool.
Water, not containing reducing agents, is used for dilution of the oxidized solution prepared for pH
utrirovannye.
2.1, 2.2. (Changed edition, Rev. N 1).
2.3. Analysis
2.3.1. A portion of the cast iron depending on the mass fraction of manganese (see table.1) is placed in a beaker with a capacity of 250 cm, 30 cm, pour the
mixture of sulphuric and phosphoric acid, the beaker cover watch glass, and heated for 5−10 min.
Table 1
| Mass fraction of manganese, % | The weight of cast iron, g | Aliquota part of the solution, see |
| From 0.10 to 0.50 |
1 | 50 |
| SV. Of 0.50 «to 2.0 |
0,5 | 25 |
Then gently pour the 10 cmof nitric acid and heated until complete dissolution of the sample.
Insoluble under these conditions, the iron is dissolved in hydrochloric acid or in hydrochloric acid with addition of nitric acid. Then the solution was poured 30 cmof a mixture of sulfuric or phosphoric acid, is evaporated until the sulphuric acid fumes and cooled. Wash the side of the Cup with water and then evaporated the solution until the appearance of sulphuric acid fumes.
The contents of the Cup cool, dissolve the salt when heated to 50−60 cmof water and filtered off the precipitate of silicic acid and graphite on the filter «white ribbon», collecting the filtrate and wash liquid in a volumetric flask with a capacity of 250 cm
. The glass and the filter cake washed three to five times with nitric acid (1:100). Filter the precipitate discarded. The contents of the flask are cooled, made up to the mark with water and mix. Aliquot part (see table.1) solution placed in a conical flask with a capacity of 250 cm
, pour water to about 50 cm
, 25 cm
of a mixture of sulfuric and phosphoric acids and 10 cm
of a solution of potassium jednolitego.
(Changed edition, Rev. N 1
).
2.3.2. The contents of the flask heated to boiling, boil for 1 min, and kept at a temperature close to the boiling point, for 40−50 min. Then solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, top up with water containing no reducing agents to the mark and mix.
Optical density of the solution measured on a spectrophotometer at a wavelength of 545 nm or photoelectrocolorimeter with a filter having a region of transmittance in the wavelength range of 530−550 nm in a cuvette with a thickness of the light absorbing layer 20 mm.
A solution of comparison, using the resulting solution, adding a few drops of a solution of sodium azotistykh for recovery of manganese acid (until the disappearance of pink color).
To amend the results of the analysis on the content of manganese in the reagents through all stages of the analysis carried out control experience, the optical density of the solution which is measured relative to its solution comparison, which is obtained similarly to the above.
The found value of the optical density of the investigated solution taking into account the optical density of the solution in the reference experiment find the amount of manganese in milligrams for the calibration schedule.
2.3.3. Construction of calibration curve
A suspension of carbonyl iron weight of 2 g were placed in a glass with a capacity of 250 cm, 50 cm, pour the
mixture of sulphuric and phosphoric acids, and dissolved by heating. The solution is oxidized by adding dropwise nitric acid, boil to remove oxides of nitrogen and cooled. The solution was transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
10 cmresulting solution was placed in eight conical flasks with a capacity of 250 cm
, the seven flasks is added consistently 1; 2; 4; 6; 8; 10 and 12 cm
standard solution B, which corresponds to 0,1; 0,2; 0,4; 0,6; 0,8; 1,0 and 1.2 mg of manganese. In the eighth flask conduct control experience on the content of manganese in the reagents.
The solution in each flask is diluted with water to 50 cm, is added to 25 cm
of a mixture of sulfuric and phosphoric acids, and 10 cm
of a solution of potassium jednolitego. Further analysis is carried out according to claim
As a solution comparison solution is used in the reference experiment.
The found values of optical density and corresponding concentrations of manganese build the calibration graph.
(Changed edition, Rev. N
1).
2.4. Processing of the results
2.4.1. Mass fraction of manganese () in percent is calculated by the formula
where the weight of cast iron, suitable fotometricheskoe aliquote part of the solution, mg;
— weight of manganese, was found in the calibration schedule, mg.
(Changed edition, Rev. N 1).
2.4.2. Allowable absolute discrepancies in the results of parallel measurements at p = 0.95 does not exceed specified in table.2.
3. TITRIMETRIC METHOD FOR IRON WITH A MASS FRACTION OF COBALT UP TO 1.0%
3.1.Determination of manganese in cast irons containing up to 1.0% chromium
3.1.1. The essence of the method
The method is based on the oxidation of divalent manganese in an acidic medium to pneumococcal neccersarily ammonium in the presence of a catalyst of silver nitrate. The obtained manganese acid octarepeat solution arsenit-sodium nitrite.
3.1.2. Reagents and solutions
Nitric acid GOST 4461−77.
Sulfuric acid GOST 4204−77 and diluted 1:4.
Orthophosphoric acid according to GOST 6552−80.
A mixture of acids: 550 cmof water gently, with continuous stirring, pour the 90 cm
of sulfuric acid, cooled, poured 100 cm
of phosphoric acid, stirred and poured 260 cm
of nitric acid.
Silver nitrate according to GOST 1277−75, solution 0,005 g/cm.
Sodium chloride according to GOST 4233−77, solution 0.005 g/cm.
Paper indicator, universal.
Ammonium neccersarily according to GOST 20478−75, a solution of 0.2 g/cm.
Arsenic anhydride according to GOST 1973−77.
Sodium mistakemistake ortho (arsenit sodium).
Sodium bicarbonate according to GOST 4201−79.
Sodium hydroxide according to GOST 4328−77, a solution of 0.15 g/cm.
Sodium atomistically according to GOST 4197−74.
Sodium arsenit-nitrite standard solution: 1.5 g of arsenious anhydride were placed in a glass with a capacity of 400−600 cm, containing 25 cm
of hot sodium hydroxide solution, dissolved under moderate heating, dilute with water to 120−130 cm
, cool. Then pour the solution of sulphuric acid (1:4) to pH 7 on the universal indicator and 2−3 cm
in excess. Add sodium bicarbonate to pH 7, universal indicator paper.
In the resulting solution dissolve 0.85 g of sodium attestatio, the solution is transferred to a volumetric flask with a capacity of 1 DM, dilute to the mark with water and mix.
Allowed the preparation of a standard solution of sodium arsenit: of 2.91 g of arsenit sodium is placed in a beaker with a capacity of 400 cm, 120−150 cm poured
water and stirred until complete dissolution of the salt.
Further preparation of the solution is carried out as arsenious anhydride. When the content of salts water of crystallization considered in the calculation of sample needed to prepare a standard solution.
The mass concentration of the solution arsenit-sodium nitrite set by standard samples of cast iron with the chemical composition, the relevant requirements of this standard, and is calculated by the formula
where — weight of standard sample, g;
— mass fraction of manganese in the standard sample, %;
the volume of the solution arsenit-sodium nitrite, spent on titration, sm
.
3.1.3. Analysis
The weight of cast iron weighing 0.5 g (at a mass fraction of manganese from 0.20 to 0.8%) or weighing 0.25 g (with a mass fraction of manganese from 0.8 to 5.0%) is placed in a conical flask with a capacity of 250 cm, 30−40 cm, pour the
mixture of acids and dissolved by heating. The solution was boiled to remove oxides of nitrogen.
The insoluble residue containing silicic acid and carbon, filtered on a medium density filter «white ribbon» and washed 5−6 times with hot water collecting the filtrate and washings in a conical flask with a capacity of 250 cm.
The solution is diluted with water to 100 cm, add 10 cm
of a solution of nitrate of silver, 20 cm
naternicola solution of ammonia, heated to boiling and boiled for 1 min, kept warm on the stove until the termination of allocation of bubbles of oxygen.
The solution was then cooled to room temperature, poured 10 cmof the sodium chloride solution is quickly titrated with a solution of arsenit-sodium nitrite to the disappearance of crimson colour
.
3.1.2,
3.1.4. Processing of the results
3.1.4.1. Mass fraction of manganese () in percent is calculated by the formula
where — volume of the solution arsenit-sodium nitrite consumed for titration, cm
;
— mass concentration of a solution of arsenit-sodium nitrite by manganese, g/cm
;
the weight of cast iron,
(Changed edition, Rev. N 1).
3.1.4.2. Allowable absolute discrepancies in the results of parallel measurements at p = 0.95 does not exceed specified in table.2.
3.2. Determination of manganese in cast irons containing more than 1,0% chromium
3.2.1. The essence of the method
The essence of the method according to claim 3.1.1 with the addition of: deformity of the elements manganese precipitated zinc oxide.
3.2.2. Reagents and solutions
Hydrochloric acid by the GOST 3118−77.
Ammonia water according to GOST 3760−79.
Zinc oxide according to GOST 10262−73, suspension in water: 50 g of zinc oxide, containing manganese, carbonates and reducing agents, placed in a porcelain mortar and triturated with pestle with hot water, then add 250−300 cmof hot water and stirred.
Zinc oxide containing carbonates and reducing agents, pre-calcined at 800 °C.
The other reagents and solutions according to claim
3.2.3. Analysis
A portion of the cast iron mass of 1 g (in mass fraction of manganese from 0.20 to 0.8%) by weight or 0.5 g (at a mass fraction of manganese from 0.8 to 5.0%) is placed in a conical flask with a capacity of 250 cm, pour 40−50 cm
of sulphuric acid (1:4) and dissolve when heated. Added dropwise nitric acid until the termination of foaming solution and 2−3 cm
in excess. The solution was evaporated until the appearance of sulphuric acid fumes, cooled. The walls of the flask is washed with water, add about 50 cm
of water and dissolved salts when heated.
If cast iron is not soluble in a mixture of sulfuric and nitric acids, the sample is dissolved in 30 cmof a mixture of hydrochloric and nitric acids in the ratio 3:1 when heated then cooled. Pour 10 cm
of sulphuric acid, evaporated the solution until the appearance of sulfuric acid vapor and again cooled. The side of the Cup washed with water, the solution was evaporated until the appearance of sulphuric acid fumes, cool, add about 50 cm
of water and dissolved salts when heated.
The solution obtained by any of these methods, transferred to a volumetric flask with a capacity of 250 cmand add ammonia solution until you see a red-brown color. In the case of the appearance of the precipitate of hydroxide is added dropwise sulfuric acid (1:4) to dissolve the residue.
To the solution was added in small portions to the suspension of zinc oxide until the complete coagulation of the precipitate of the hydroxides (at the bottom of the bulb should be a slight excess of a suspension of zinc oxide).
The contents of the flask are cooled, made up to the mark with water, stirred and allowed sediment to settle.
The solution is filtered through a dry filter medium density «white ribbon» in a dry volumetric flask with a capacity of 100 cm, discarding the first portions of the filtrate. Fill the flask to the mark, the solution is transferred to a conical flask with a capacity of 250 cm
, is added 40 cm
of the mixture of acids and end the definition according to claim 3
.1.3.
3.2.2,
3.2.4. Processing of the results — p.3.1.4.
4. POTENTIOMETRIC METHOD FOR CAST IRON WITH A MASS FRACTION OF VANADIUM TO 0.10%
4.1.The essence of the method
The method is based on the oxidation of bivalent manganese to trivalent potassium permanganate in neutral medium. Iron, chromium and other elements that hinder the determination of manganese, bind in the pyrophosphate complexes.
4.2. Apparatus, reagents and solutions
The setup for potentiometric titration with a pair of electrodes: platinum — saturated calomel; platinum — tungsten or platinum — platinum.
Hydrochloric acid GOST 3118−77, diluted 1:1.
Nitric acid GOST 4461−77.
Sulfuric acid GOST 4204−77, diluted 1:20.
Sodium pyro phosphate according to GOST 342−77, a solution of 120 g/DM.
Ammonia water according to GOST 3760−79 diluted 1:1.
Urea according to GOST 6691−77, a solution of 50 g/DM.
Paper indicator, universal.
Sodium oxalate according to GOST 5839−77, recrystallized and dried at 105−110 °C to constant weight.
Potassium permanganate according to GOST 20490−75, a standard solution with a molar concentration equivalent to 0.05 mol/DM: 1,58 g of recrystallized and dried at 120 °C of potassium permanganate are dissolved in 1 DM
of water. The solution is allowed to stand for 6 days in a closed bottle, then it sivunirmut in a bottle of dark glass.
The mass concentration of the standard potassium permanganate solution set oxalate sodium.
In a conical flask with a capacity of 500 cmis placed 200 cm
of sulphuric acid (1:20), heated to 70−75 °C and added dropwise a solution of potassium permanganate until a stable pink color.
The contents of the flask are added 0.1 g of sodium oxalate and after dissolution of the sample titrated with stirring with a solution of potassium permanganate until stable for 1 min pink color. By the end of the titration, the solution temperature should not be below 60 °C.
The mass concentration of a solution of potassium permanganate (), expressed in grams of manganese, calculated by the formula
where 0,656 — the ratio of the mass concentration of a solution of potassium permanganate specified by oxalate sodium, on a mass concentration expressed in grams of manganese; — weight of sodium oxalate, g;
— the volume of potassium permanganate solution consumed for titration, sm
.
4.3. Analysis
The weight of cast iron weighing 1 g is placed in a beaker with a capacity of 250 cmand dissolve in low heat 40−50 cm
of hydrochloric acid (1:1), added dropwise nitric acid until the termination of foaming. The solution was boiled to remove oxides of nitrogen, evaporated to 5−8 cm
, add 50 cm
of water and dissolved salts when heated.
The insoluble residue containing silicic acid and carbon, filtered through a medium density filter «white ribbon», washed 5−6 times with hot water collecting the filtrate and washings in a volumetric flask with a capacity of 250 cm.
The filtrate is cooled, made up to the mark with water and mix.
Aliquot part of test solution 50 cmis placed in a beaker with a capacity of 400 cm
, 5 cm pour the
urea solution, 100 cm
of sodium pyrophosphate solution and set the pH near 7 on the universal indicator paper by adding, if necessary, dropwise hydrochloric acid (1:1) or a solution of ammonia (1:1).
Thus prepared solution is titrated with a solution of potassium permanganate for potentiometric set to jump in the potential.
(Changed edition, Rev. N
1).
4.4. Processing of the results
4.4.1. Mass fraction of manganese () in percent is calculated by the formula
where is the volume of potassium permanganate solution consumed for titration, cm
;
— mass concentration of a solution of potassium permanganate for manganese, g/cm
;
the weight of cast iron,
(Changed edition, Rev. N 1).
4.4.2. Allowable absolute discrepancies in the results of parallel measurements at p = 0.95 does not exceed specified in table.2.
5. ATOMIC ABSORPTION METHOD
5.1. Atomic absorption method for the determination of manganese GOST 12348−78 with additions.
5.2. Allowable absolute discrepancies in the results of parallel measurements at p = 0.95 does not exceed specified in table.2.
Table 2
| Mass fraction of manganese, % | Norms of accuracy and norms of precision control, % | ||||
| From 0.1 to 0.2 incl. |
0,012 | 0,015 | 0,012 | 0,015 | 0,008 |
| SV. 0,2 «0,5 « |
0,019 | 0,024 | 0,019 | 0,024 | 0,012 |
| «0,5» 1,0 « |
0,026 | 0,033 | 0,028 | 0,034 | 0,017 |
| «1,0» 2,0 « |
0,04 | 0,05 | 0,04 | 0,05 | 0,02 |
| «To 2.0» 5,0 « |
0,06 | 0,08 | 0,06 | 0,08 | 0,04 |
| «5,0» 10 « |
0,08 | 0,11 | 0,09 | 0,11 | 0,06 |
| «10» 25 « |
0,15 | 0,19 | 0,15 | 0,19 | 0,10 |
(Changed edition, Rev. N 1).
