GOST 16412.4-91
GOST 16412.4−91 iron Powder. Methods for determination of manganese
GOST 16412.4−91
Group B59
STATE STANDARD OF THE USSR
IRON POWDER
Methods for determination of manganese
Iron powder.
Methods for the determination of manganese
AXTU 0809
Date of introduction 1992−07−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Academy of Sciences of the Ukrainian SSR
DEVELOPERS
V. N. Klimenko, PhD. tech. Sciences; A. E. kushchevsky, PhD. chem. Sciences; V. A. Dubok, PhD. chem. Sciences (head of subject); V. I. Kornilov, candidate. chem. Sciences; V. V. Garbuz, PhD. chem. Sciences; L. D. Bernatsky
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from
3. REPLACE GOST 16412.4−80
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced | Paragraph number section |
| GOST 244−76 | 2.2 |
| GOST 1277−75 | 2.2 |
| GOST 3760−79 | 3.2 |
| GOST 4197−74 | 2.2 |
| GOST 4201−79 | 2.2 |
| GOST 4204−77 | 2.2; 3.2 |
| GOST 4328−77 | 2.2 |
| GOST 4461−77 | 2.2; 3.2 |
| GOST 6552−80 | 2.2; 3.2 |
| GOST 10929−76 | 3.2 |
| GOST 20478−75 | 3.2 |
| GOST 20490−75 | 3.2 |
| GOST 28473−90 | Sec. 1 |
This standard establishes titrimetric persulfate (with a mass fraction of manganese from 0.1% and above) and photometric (at a mass fraction of manganese from 0.02 to 0.8%) methods for determination of manganese in iron powder.
1. GENERAL REQUIREMENTS
General requirements for methods of analysis GOST 28473.
2. TITRIMETRIC METHOD FOR THE DETERMINATION OF MANGANESE
2.1. The essence of the method
The method is based on the oxidation of divalent manganese neccersarily ammonium in the presence of a catalyst of silver nitrate to manganese acid with subsequent titration of pneumococcal of manganese with a solution of arsenit-sodium nitrite. As a titrated solution allowed the use of sodium thiosulfate.
2.2. Reagents and solutions
Sulfuric acid according to GOST 4204, and diluted 2:3.
Nitric acid according to GOST 4461.
Orthophosphoric acid according to GOST 6552.
A mixture of acids: 500 cmof water gently, with continuous stirring, pour 125 cm
of sulfuric acid, cooled, poured 100 cm
of phosphoric acid and 275 cm
of nitric acid and stirred.
Ammonium neccersarily (persulfate) according to GOST 20478, a freshly prepared solution with a mass fraction of 15%.
Silver nitrate according to GOST 1277, a solution with a mass fraction of 0.1%.
Sodium carbonate acidic, GOST 4201.
Sodium hydroxide according to GOST 4328, a solution with a mass fraction of 15%.
Sodium atomistically according to GOST 4197.
Sodium mistakemistake containing atomistically sodium (arsenit-sodium nitrite), titrated a solution of 0.2 g of arsenious anhydride were placed in a glass with a capacity of 600 cm, is dissolved in 25 cm
of sodium hydroxide solution with a mass fraction of 15% at the moderate heating and continuous stirring. The solution is diluted with water to 200 cm
, cooled, poured dilute sulphuric acid until acid reaction to litmus, and add an excess of 2−3 cm
. The excess sulfuric acid neutralized with sodium carbonate acidic to litmus. To the obtained solution are added 0.85 g of sodium attestatio and mix to dissolve the salt. The contents of the beaker poured into a volumetric flask with a capacity of 1 DM
, made up to the mark with water, mix thoroughly.
A solution of arsenit-sodium nitrite can also be prepared from mistakemistake sodium: 0.4 g of arsenous acid sodium dissolved in 200 cmof water is added 0.75 g of sodium attestatio, was stirred until complete dissolution, dilute with water to 1 DM
and mix thoroughly.
Sodium thiosulfate crystal (Chernovetskiy) according to GOST 244, titrated a solution of 0.65 g of sodium thiosulfate dissolved cold in 1 DMsvejeprokipachenna and chilled water. To the obtained solution for its stabilization is added 0.2 g of sodium carbonate, thoroughly mixed and allowed to settle 10 days. The sodium thiosulfate stored in a dark bottle, protected from the action of oxidants and carbon dioxide in the air.
Set the mass concentration of the solution michalowskiego sodium and servational sodium standard sample of steel, similar in chemical composition and mass fraction of manganese to analyze the iron powder.
The mass concentration of the solution of arsenit-sodium nitrite or sodium thiosulfate (), expressed in grams of manganese per 1 cm
of a solution, calculated by the formula
where — mass fraction of manganese in the standard sample, %;
— weight of standard sample, g;
the volume of the solution of arsenit-sodium nitrite or sodium thiosulfate consumed in the titration, sm
.
2.3. Testing
When determining the mass fraction of manganese take the weight of iron powder with a mass of 1 g (in mass fraction of manganese from 0.1 to 0.2%); 0.2 g (with a mass fraction of manganese from 0.2% and above) and placed in a conical flask with a capacity of 500 cm, 30 cm, pour the
mixture of acids and the contents of the flask was heated moderately to dissolve the entire sample. The solution was boiled for 5 min to remove oxides of nitrogen. To the solution add 100 cm
of water 5 cm
of a solution of nitrate of silver, 20 cm of
a freshly prepared solution of ammonium naternicola, bring to the boil and boil the contents of the flask for not more than 1 min. the flask with the solution is removed from the plate, incubate in a warm place for 5 minutes (until the termination of allocation of bubbles of oxygen). Then cooled in running water to room temperature and immediately titrated acid manganese solution of arsenit-sodium nitrite (or sodium thiosulfate). Titrated the solution is poured with a speed of 5−6 cm
/min until the colour of the titrated solution in pale pink, the subsequent portions of the solution are added dropwise until complete disappearance of the pink color.
2.4. Processing of the results
2.4.1. Mass fraction of manganese () in percent is calculated by the formula
where — volume of the solution of arsenit-sodium nitrite or sodium thiosulfate consumed in the titration of sample solution, cm
;
the volume of the solution of arsenit-sodium nitrite or sodium thiosulfate consumed for the titration of a solution in the reference experiment, cm
;
— mass concentration of a solution of arsenit-sodium nitrite or sodium thiosulfate, expressed in g/cm
of manganese;
— weight of iron powder, g
.
2.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in the table.
| Mass fraction of manganese, % | Allowable absolute differences, % |
| From 0.02 to 0.05 incl. | 0,005 |
| SV. Of 0.05 «to 0.20 « | 0,01 |
| «To 0.20» and 0.40 « | 0,02 |
| «And 0.40» to 0.80 « | 0,03 |
3. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF MANGANESE
3.1. The essence of the method
The method is based on the oxidation of ions of bivalent manganese to the pneumococcal periodate potassium in sulfuric acid solution. Interfere with the determination of trivalent ions of iron. For masking, as well as to prevent the formation nerastvorim connections periodate manganese using phosphoric acid.
3.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Sulfuric acid according to GOST 4204, diluted 1:1.
Nitric acid according to GOST 4461.
Orthophosphoric acid according to GOST 6552.
Ammonia water according to GOST 3760.
The mixture of acids to dissolve: to 500 cmof water gently, with continuous stirring, pour the 90 cm
of sulphuric acid, cool and pour the 275 cm
of nitric acid.
A mixture of sulfuric and phosphoric acids to 700 cmof water gently with continuous stirring poured 150 cm
of sulfuric acid, cooled, poured 150 cm
of phosphoric acid, stirred and cooled.
Potassium ignominy (periodic) according to normative-technical documentation.
Hydrogen peroxide according to GOST 10929, a solution with a mass fraction of 3%.
Carbonyl iron, OS.h.
Potassium permanganate according to GOST 20490.
Water free from reducing substances in a flask with a capacity of 2 DM1 DM poured
water, poured dropwise sulfuric acid to a pH of 3 by universal indicator paper and heated to boiling, then remove the flask from the heat, add a few crystals of potassium periodate, boil for 5 minutes and cooled.
Standard solutions of manganese.
Solution a: 0,2877 g potassium permanganate placed in a beaker with a capacity of 250 cm, and dissolved in 100 cm
of water, add 20 cm
of dilute sulfuric acid, heat, add dropwise a solution of hydrogen peroxide to bleaching and the solution is evaporated to release vapors of sulfuric acid. The solution was cooled, added to 50 cm
of water, transferred to a volumetric flask with a capacity of 1 DM
, adjusted to the mark with water and mix.
1 cmstandard solution contains 0.0001 g of manganese.
Solution B: 200 cmstandard solution And placed in a volumetric flask with a capacity of 1 DM
, adjusted to the mark with water and mix, cook before use.
1 cmstandard solution B contains 0,00002
g of manganese.
3.3. Analysis
For the determination of manganese take the following sample of iron powder weight: 1 g (in mass fraction of manganese from 0.02 to 0.20%), 0.5 g (at a mass fraction of manganese from 0.20 to 0.40%), 0.25 g (when the mass fraction of manganese from 0.40 to 0.80%) were placed in a glass with a capacity of 250 cm, 50 cm, pour the
mixture of acids and dissolved under moderate heating. After dissolving iron powder in the solution was heated for 3−5 min to remove oxides of nitrogen. The contents of the beaker cool, add 20 cm
of water, transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix. Aliquot part of the solution 10 cm
is placed in a conical flask with a capacity of 250 cm
, adding 25 cm
of water, 15 cm
of a mixture of sulfuric and phosphoric acids, 0.5 g of potassium jednolitego. The contents of the flask heated to boiling, boiled for 3 min and allowed to stand in a warm place for 10 min. the solution was Then cooled, transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
The optical density of the analyzed solution is measured on a spectrophotometer at 525 nm or photoelectrocolorimeter with a filter having a region of transmittance at
525−530 nm.
Solution comparison is the suspension of carbonyl iron, carried out through all stages of the analysis.
The results of the analysis calculated by the calibration gra
fico.
3.3.1. Construction of calibration curve
In seven conical flasks with a capacity of 250 cmis placed 0.1 g carbonyl iron, and six of them successively added 1, 3, 5, 7, 9, 11 cm
standard solution B of manganese, which corresponds to 2·10
; 6·10
; 1·10
; 1,4·10
; 1,8·10
; 2,2·10
g manganese. The seventh flask conduct control experience on the manganese content in the reagent. Then pour 20 cm
of the mixture of acids to dissolve. The solution was boiled to remove oxides of nitrogen, add 25 cm
of water, 0.5 g of potassium Odnokolenko, boiled for 3 min and leave in a warm place for 10 min. the Solutions were cooled, transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
The value of optical density of colored solutions are measured on the spectrophotometer at a wavelength of 525 nm or photoelectrocolorimeter with a filter having a region of transmittance at 525−530 nm.
Solution comparison is the solution of the reference experiment.
On the found values of optical density and corresponding masses of manganese build calibration g
Rafik.
3.4. Processing of the results
3.4.1. Mass fraction of manganese () in percent is calculated by the formula
where is the mass of manganese was found in the calibration schedule g;
— the weight of the portion of the sample corresponding to aliquote part of the solution,
3.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in the table.
