GOST 15027.3-77
GOST 15027.3−77 Bronze without tin. Methods for determination of iron (with Amendments No. 1, 2)
GOST 15027.3−77
Group B59
INTERSTATE STANDARD
BRONZE WITHOUT TIN
Methods of iron determination
Non-tin bronze.
Methods for the determination of iron
AXTU 1709
Date of introduction 1979−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 20.06.77* N 1614
______________
* Probably, the error of the original. Should read:
3. REPLACE GOST 15027.3−69
4. The standard fully complies ST SEV 1534−79
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Section number, paragraph, sub-paragraph |
| GOST 61−75 |
4.2 |
| GOST 199−78 |
4.2 |
| GOST 493−79 |
Chapeau |
| GOST 614−97 |
Chapeau |
| GOST 859−2001 |
7.2 |
| GOST 3118−77 |
2.2, 3.2, 4.2, 5.2, 6.2, 7.2 |
| GOST 3760−79 |
2.2, 3.2, 4.2, 5.2, 7.2 |
| GOST 3773−72 |
2.2 |
| GOST 4204−77 |
2.2, 4.2, 5.2, 6.2 |
| GOST 4220−75 |
2.2 |
| GOST 4238−77 |
4.2, 5.2 |
| GOST 4461−77 |
2.2, 3.2, 4.2, 5.2, 6.2, 7.2 |
| GOST 4478−78 |
3.2, 5.2, 7.2 |
| GOST 5456−79 |
4.2, 5.2 |
| GOST 5817−77 |
7.2 |
| GOST 6552−80 |
2.2 |
| GOST 10484−78 |
2.2, 6.2 |
| GOST 10652−73 |
3.2 |
| GOST 10929−76 |
6.2 |
| GOST 18175−78 |
Chapeau |
| GOST 18300−87 |
2.2, 4.2 |
| GOST 22867−77 |
4.2 |
| GOST 25086−87 |
1.1, 2.4.4 |
| THAT 6−09−5384−88 |
2.2 |
| THAT 6−09−5446−89 |
2.2 |
6. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)
7. EDITION with Amendments No. 1, 2 approved in February 1983, March 1988 (IUS 6−83, 6−88)
This standard establishes titrimetric methods for the determination of iron (at mass proportion of iron is from 0.4% to 7%), photometric methods of determination of iron (at mass fraction of iron from 0.01% to 1%) and atomic absorption method for determination of iron (at mass fraction of iron from 0.01% to 7%) in tin bronze according to GOST 18175, GOST and GOST 614 493.
(Changed edition, Rev. N 1, 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 with the addition of sec. 1 GOST 15027.1.
(Changed edition, Rev. N 2).
2. TITRIMETRIC METHOD FOR DETERMINATION OF IRON
2.1. The essence of the method
The method is based on the recovery of trivalent iron to bivalent, the bivalent iron titration solution of potassium dichromate with potentiometric end-finding or visual titration method with indicator or diphenylamine sodium salt diphenylaminochloroarsine acid.
2.2. Apparatus, reagents and solutions
A potentiometer with a saturated calomel electrode and a platinum indicator electrode.
Hydrochloric acid according to GOST 3118, diluted 1:1.
Nitric acid according to GOST 4461, diluted 1:1.
Sulfuric acid according to GOST 4204, diluted 1:1.
Orthophosphoric acid according to GOST 6552.
A mixture of acids, is prepared as follows: 300 cmof sulphuric acid diluted 1:1, and 300 cm
of phosphoric acid diluted with water to 1 DM
.
Ammonia water according to GOST 3760 and diluted 1:1.
Wash solution; prepared as follows: 5 cmof ammonia solution diluted with water to 1 DM
.
Tin dichloride TU 6−09−5384*, solution 100 g/lis prepared as follows: 10 g of drug is dissolved in 50 cm
of concentrated hydrochloric acid and heated to a clear solution. After cooling, the solution topped up with water to 100 cm
.
________________
* The one referred to here and hereinafter, not shown. For additional information, please refer to the link. — Note the manufacturer’s database.
Mercury dichloride, a solution of 40 g/DM.
Potassium dichromate according to GOST 4220, or 0,17 0,008 mol/DMsolution; prepared as follows: weighed respectively 4,9037 or 2,4519 g, dried for 2 h at (160±5) °C, dissolved in water, transferred to a volumetric flask with a capacity of 1 DM
and topped to the mark with water.
1 cmof 0.17 mol/DM
solution with 0,005584 grams of iron and 1 cm
of 0.008 mol/DM
solution with 0,002792 g of iron.
Diphenylamine on the other 6−09−54−40, a solution of 10 g/DMin concentrated sulfuric acid.
Sodium salt diphenylaminochloroarsine acid solution 2 g/DM.
Hydrofluoric acid according to GOST 10484.
Ammonium chloride according to GOST 3773.
2.3. Analysis
A sample of alloy weighing 1 g is placed in a beaker with a capacity of 400 cm, and dissolved in 20 cm
of nitric acid, diluted 1:1, when heated. The solution is diluted with water to approximately 200 cm
, was added a solution of ammonia until the formation of a soluble blue complex of copper. The solution was maintained at (60±5) °C for coagulation of the precipitate of iron hydroxide.
The precipitate was filtered off on a filter of medium density. The glass and the precipitate washed with flushing solution. The precipitate is dissolved in 20 cmof hot hydrochloric acid, diluted 1:1, the filter is washed 5−6 times with hot water and repeat the precipitation of iron hydroxide to complete removal of copper ions. The precipitate, after washing with flushing solution dissolved in 10 cm
of hot hydrochloric acid, diluted 1:1, and the filter washed with hot water. The solution is heated to boiling, restore trivalent iron by addition of a few drops of solution of tin dichloride to a bleaching solution and pour 2−3 drops in excess. Then the solution was cooled, add 5 cm
of a solution of dichloride of mercury 15 cm
of the mixture of acids, dilute with water to approximately 200 cm
and titrated solution of potassium dichromate potentiometric, using a saturated calomel electrode and a platinum indicator electrode, or add two drops of diphenylamine solution or 1 cm
of a solution of the sodium salt diphenylaminochloroarsine acid and titrated to the appearance of the violet color of the solution.
2.1−2.3. (Changed edition, Rev. N 1).
2.3.1. For bronzes with a mass fraction of silicon to 0.05%
A portion of the alloy weight 2 g (when the mass fraction of iron is from 0.4% to 3%) and a mass of 1 g (in mass percentage of iron in excess of 3% to 7%) were placed in a glass with a capacity of 400 cmand dissolved by heating in 20 or 10 cm
of nitric acid, diluted 1:1. Then add 5 g of ammonium chloride and water to 200 cm
.
2.3.2. For bronzes with a mass fraction of silicon in excess of 0.05%
A portion of the alloy weight 2 g (when the mass fraction of iron is from 0.4% to 3%) and a mass of 1 g (in mass percentage of iron in excess of 3% to 7%) was placed in a platinum Cup and add 20 or 10 cmof nitric acid, diluted 1:1 and 10−5 drops of hydrofluoric acid and dissolved by heating. Then add 10 cm
sulphuric acid diluted 1:1, and evaporated until white smoke of sulfuric acid. The residue is cooled, dissolved in water, the solution was transferred to a beaker with a capacity of 400 cm
and, if necessary, filtered. To the filtrate add 5 cm
of nitric acid, diluted 1:1, water to 200 cm
, 5 g of ammonium chloride and ammonia solution before the formation of a blue complex of copper.
2.3.1,
2.4. Processing of the results
2.4.1. Mass fraction of iron () in percent is calculated by the formula
where — the volume of 0.17 or 0.008 mol/DM
solution of potassium dichromate consumed for titration, cm
;
— weight of iron, corresponding to 1 cm
or 0,17 0,008 mol/DM
solution of potassium dichromate, g;
— weight alloy, g
.
2.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.1.
Table 1
| Mass fraction of iron, % |
|
|
| From 0.01 to 0.03 |
0,003 | 0,007 |
| SV. Of 0.03 «to 0.05 |
0,005 | 0,01 |
| «0,05» 0,10 |
0,008 | 0,02 |
| «To 0.10» to 0.20 |
0,015 | 0,04 |
| «0,2» 0,4 |
0,02 | 0,05 |
| «Of 0.4» to 1.0 |
0,03 | 0,07 |
| «Of 1.0» to 3.0 |
0,05 | 0,1 |
| «3,0» 5,0 |
0,10 | 0,2 |
| «A 5.0» to 7.0 |
0,15 | 0,4 |
(Changed edition, Rev. N 2).
2.4.3. The absolute discrepancies of the analysis results 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 table.1.
2.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to State standard samples without tin bronzes, certified in the prescribed manner or by comparing the analysis results obtained by titrimetric and atomic absorption methods in accordance with GOST 25086.
2.4.3,
3. TITRIMETRIC CHELATOMETRIC METHOD FOR DETERMINATION OF IRON
3.1. The essence of the method
The method is based on titration of ferric iron by solution of Trilon B with the use of sulfosalicylic acid as indicator.
3.2. Reagents and solutions
Nitric acid according to GOST 4461 and diluted 1:1.
Hydrochloric acid according to GOST 3118 and diluted 1:1 and 1:4.
Ammonia water according to GOST 3760 and diluted 1:1 and 1:50.
Sulfosalicylic acid according to GOST 4478, solution 100 g/DM.
Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid 2-water (Trilon B) according to GOST 10652; 0,025 mol/DMsolution; prepared as follows: 9,305 g Trilon B dissolved in 500 cm
of water when heated, transferred to a volumetric flask with a capacity of 1 DM
and topped to the mark with water.
The iron standard sample (CO) N 126 (low carbon steel).
Standard solution of iron; prepared as follows: 1,005 g WITH N 126 was dissolved with heating in 20 cmof nitric acid, diluted 1:1. The solution was boiled to remove oxides of nitrogen, 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 0.001 g of iron.
The installation of the titer of the solution Trilon B
10 cmof a standard solution of iron was placed in a conical flask with a capacity of 250 cm
, add 20 cm
of water and neutralized with ammonia solution diluted 1:1 before passing blue color of the indicator paper, Congo lilac, then add 5 cm
of hydrochloric acid diluted 1:4, top up with water to 100 cm
and further analysis are as indicated in claim 3.3.
3.3. Analysis
A sample of alloy weighing 0.5 g (for the mass concentration of iron up to 3%) and 0.25 g (when the mass fraction of iron in excess of 3%) is dissolved by heating in 20 cmof nitric acid, diluted 1:1 in glass with a capacity of 300 cm
, is diluted with water to about 200 cm
, and add the ammonia solution before the formation of soluble blue ammonium complex copper. The solution was maintained at (60±5) °C for coagulation of iron hydroxide.
The precipitate was filtered off on a medium density filter and washed with ammonia solution, diluted 1:50. The precipitate is washed with hot water into a glass, which conducted the deposition, and dissolved in 10 cmof hot hydrochloric acid, diluted 1:1.
The filter is washed with hot water and repeat the precipitation of iron hydroxide in ammonia solution, filtering and washing the precipitate. The precipitate of iron hydroxide filter wash with hot water in a conical flask with a capacity of 250 cm, is dissolved in 10 cm
of hot hydrochloric acid, diluted 1:1, and washed the filter with hot water.
The flask with the solution was heated until complete dissolution of the precipitate is neutralized with ammonia solution diluted 1:1 before passing on blue indicator paper, Congo lilac, add 5 cmof hydrochloric acid diluted 1:4, made up to 100 cm
and heated to 70 °C. Pour 5 cm
sulfosalicylic acid solution and titrate the hot solution with a solution of Trilon B before transition of colouring from brown-red to lemon yellow.
3.4. Processing of the results
3.4.1. Mass fraction of iron () in percent is calculated by the formula
where — volume of solution Trilon B, used for titration, cm
;
— weight of iron, corresponding to 1 cm
of 0.025 mol/DM
solution of Trilon B, g;
— the weight of the portion of alloy,
3.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.1.
(Changed edition, Rev. N 2).
3.4.3. The absolute discrepancies of the analysis results 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 table.1.
3.4.4. Control of accuracy of analysis results is carried out according to claim
3.4.3,
4. PHOTOMETRIC 1,10-PHENANTHROLINE METHOD FOR IRON DETERMINATION
4.1. The essence of the method
The method is based on formation of a colored iron complex with 1,10-fenantrolina or -dipyridil at pH 5 in the presence of sodium acetate and hydroxylamine hydrochloride after separation of iron by coprecipitation with aluminum hydroxide.
4.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Sulfuric acid according to GOST 4204, and diluted 1:1.
Hydrochloric acid according to GOST 3118, diluted 1:1.
Nitric acid according to GOST 4461, diluted 1:1.
Ammonia according to GOST 3760, diluted 1:50 and 1:1.
Acetic acid according to GOST 61.
Sodium acetate according to GOST 199.
Phenolphthalein solution in ethanol, 1 g/DM.
Rectified ethyl alcohol according to GOST 18300.
Ammonium — aluminum sulfate (alum alimohammadian) according to GOST 4238, solution, prepared as follows: 10 g of alum is dissolved in 1 DMof water with 10 cm
of concentrated sulfuric acid.
Ammonium nitrate according to GOST 22867, a solution of 100 g/DM.
Hydroxylamine hydrochloric acid according to GOST 5456, a freshly prepared solution of 10 g/DM.
1,10-fenantrolin, solution; is prepared as follows: 2.5 g of 1.10-phenanthroline dissolved by heating in a small amount of water with a few drops of hydrochloric acid and dilute with water to 1 DM. Preserve in a dark vessel.
-dipyridyl, solution; is prepared as follows: 1.5 g
of dipyridyl dissolved by heating in a small amount of water with a few drops of hydrochloric acid, and dilute with water to 1 DM
. Preserve in a dark vessel.
Buffer solution; prepared as follows: 272 g sodium acetate and dissolve in 500 cmof water, add 240 cm
of acetic acid, filter and add water to 1 DM
.
The reaction mixture, freshly prepared; prepared as follows: one part of a solution of hydroxylamine hydrochloric acid is mixed with one part of the 1,10-phenanthroline or -dipyridyl and with the two parts of buffer solution.
Standard solutions of iron.
Solution A, prepared as follows: 0,5025 g standard sample N 126 steel (low carbon steel) was dissolved in 20 cmof nitric acid, diluted 1:1. The resulting solution is boiled to remove oxides of nitrogen, 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 0.0005 g of iron.
Solution B is prepared on the day of application in the following way: 5 cmsolution And placed in a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof solution B contains 0,000025 g of iron.
(Changed edition, Rev. N 1, 2).
4.3. Analysis
4.3.1. For bronzes not containing silicon
The weight of bronze weighing 0.5 g were placed in a glass with a capacity of 250 cm, cover with a watch glass and carefully dissolved by heating in 15 cm
of nitric acid, diluted 1:1. The glass solution was cooled, washed the walls of the glass and the glass a small amount of water and the solution diluted with water to 150 cm
. Add 5 cm
of a solution of alum alimohammadian (for bronzes that do not contain aluminum), 10 cm
of ammonium nitrate solution and ammonia diluted 1:1, until the formation of a soluble blue complex of copper. The solution is kept at 60 °C for coagulation of the precipitate hydroxides of iron and aluminum. The separated precipitate was filtered off on a medium density filter and washed with ammonia solution, diluted 1:50. The precipitate is dissolved in 10 cm
of hot hydrochloric acid, diluted 1:1, the filter carefully washed with hot water, collecting the filtrate in a beaker, in which was conducted the deposition, and re-precipitated hydroxide of iron and aluminum with ammonia. The precipitate was filtered off, washed with ammonia solution, diluted 1:50, dissolve 10 cm
of hot hydrochloric acid, diluted 1:1, and the filter washed with hot water, collecting the filtrate in a beaker, in which was conducted the deposition. The solution was transferred to volumetric flask and diluted to the appropriate volume and depending on the content of iron in bronze aliquote take part in accordance with the table.3.
Table 3
| Mass fraction of iron, % |
The volume of solution, cm |
The volume aliquote part of the solution, cm |
The weight of the portion corresponding to aliquote part of the solution, g |
| To 0.05 |
50 | 25 | 0,25 |
| SV. 0.05 to 0.2 |
100 | 10 | 0,05 |
| «0,2» 0,5 |
100 | 5 | 0,025 |
| «0,5» 1,0 |
200 | 5 | 0,0125 |
Aliquot part of the solution is placed in a volumetric flask with a capacity of 50 cm, top up with water to 25 cm
and neutralized with ammonia, diluted 1:1, phenolphthalein, add 1 cm
of hydrochloric acid and 12 cm
of the reaction mixture, made up to the mark with water and mix. After 30 min measure the optical density on the spectrophotometer in a cuvette length of 1 cm at
=510 nm or photoelectrocolorimeter with a green filter. Solution comparison is the solution of the reference experiment.
(Changed edition, Rev. N 1).
4.3.2. For silicon bronze
The weight of bronze weighing 0.5 g is placed in a platinum Cup and dissolved by heating in 10 cmof nitric acid, diluted 1:1, and 2−3 cm
hydrofluoric acid. After dissolution, the sample solution was cooled, add 10 cm
sulphuric acid diluted 1:1, and evaporated until a white smoke of sulfuric acid. The Cup is cooled, carefully washed the walls of the Cup with water and dissolve salt in the water when heated. The solution was transferred to a beaker with a capacity of 250 cm
, dilute with water to 150 cm
, add 5 cm
of a solution of alum alimohammadian and further analysis are as indicated in claim
4.3.3. For lead bronze
The weight of bronze weighing 0.5 g is dissolved in 15 cm.of nitric acid diluted 1:1, when heated in glass with a capacity of 250 cm
. After dissolve and remove oxides of nitrogen by boiling and transfer the solution into volumetric flask and diluted to the appropriate volume and depending on the content of iron in bronze aliquot selected part as specified in table.3.
Aliquot part of the solution placed in a beaker with a capacity of 250 cm, add 10 cm
boiled nitric acid, diluted 1:1, add water to a volume of about 100 cm
and produce copper and lead by electrolysis on a platinum cylindrical electrode within 30 minutes After the end of electrolysis the electrode is washed with a small amount of water into the same beaker, pour 5 cm
of a solution of alum alimohammadian and further analysis are as indicated in claim
4.3.4. For bronzes with a mass fraction of tin, antimony and lead in excess of 0.05%
The weight of bronze weighing 0.5 g were placed in a glass with a capacity of 250 cmand dissolved in 15 cm
of the mixture to dissolve when heated. In case of incomplete dissolution dropwise, carefully add bromine. After dissolution, add 10 cm
of perchloric acid and evaporated the solution at a moderate heat to release a thick white smoke of perchloric acid and clarification of the solution. The residue is cooled, rinse walls of beaker with water, add water to volume of 30 cm
and heated to dissolve the salts. Add 5 cm
of sulphuric acid diluted 1:1, 50 cm
of water and boil it. After cooling, the solution was filtered through a dense filter, and washed 3−5 times with hot water. The filter is discarded. To the filtrate add 5 cm
of a solution of alum alimohammadian and further analysis is carried out as specified in clause
(Added, Rev. N 1)
.
4.4. Construction of calibration curve
In a volumetric flask with a capacity of 50 cmpoured from microburette consistently 0; 0,2; 0,5; 1,0; 1,5; 2,5; 3,5 and 5.0 cm
of solution B, add water to 25 cm
, pour 2−3 drops of solution of phenolphthalein and neutralized with ammonia, diluted 1:1. Further analysis are as indicated in claim
Solution comparison is the solution not containing iron.
On the found values of optical densities of solutions and their corresponding grades of iron to build the calibration graph.
4.5. Processing of the results
4.5.1. Mass fraction of iron () in percent is calculated by the formula
where is the mass of iron was found in the calibration schedule g;
— the weight of the portion of alloy, suitable aliquote part of the solution,
4.5.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.1.
(Changed edition, Rev. N 2).
4.5.3. The absolute discrepancies of the analysis results 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 table.1.
4.5.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to State standard samples without tin bronzes, certified in the prescribed manner, or by comparing the results of analysis of the obtained photometric and atomic absorption methods in accordance with GOST 25086.
4.5.3,
5. SULFOSALICYLATE PHOTOMETRIC METHOD FOR DETERMINATION OF IRON
5.1. The essence of the method
The method is based on the formation of iron (III) yellow colored complex with sulfosalicylic acid in an ammonia solution at pH 8−10 after separation of iron by coprecipitation with aluminum hydroxide.
5.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Nitric acid according to GOST 4461, diluted 1:1.
Hydrochloric acid according to GOST 3118, diluted 1:1.
Sulfuric acid according to GOST 4204, and diluted 1:1.
Ammonia water according to GOST 3760, diluted 1:1, 1:50.
Alum alimohammadian according to GOST 4238, solution; is prepared as follows: 10 g of alum is dissolved in 1 DMof water with the addition of 10 cm
of concentrated sulfuric acid.
Hydroxylamine hydrochloric acid according to GOST 5456, a freshly prepared solution of 100 g/DM.
Sulfosalicylic acid according to GOST 4478, a solution of 200 g/DM.
Standard solutions of iron.
Solution A, prepared as follows: 1,005 g of the standard sample N 126 (low carbon steel) was dissolved in 20 cmof nitric acid, diluted 1:1. The resulting solution is boiled to remove oxides of nitrogen, 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 0.001 g of iron.
Solution B is prepared on the day of application. This 10 cmof the solution And transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof a solution contains 0.0001 g of iron.
5.3. Analysis
5.3.1. For alloys not containing silicon
The sample of bronze with a weight of 1 g was placed in a beaker with a capacity of 250 cm, cover with a watch glass and dissolved by heating in 15 cm
of nitric acid, diluted 1:1. After dissolution, the samples rinsed the glass and the side of the Cup a small amount of water, add 5 cm
of a solution of alum alimohammadian (for bronzes containing no aluminum), and the solution is diluted with water to 100 cm
, heated to 60−70 °C and ammonia is added, diluted 1:1, until the formation of a soluble blue complex of copper. The solution is kept at 50−60 °C for coagulation of the precipitate hydroxides of iron and aluminum. The precipitate was filtered off on a medium density filter, the beaker and the solution was washed with a hot solution of ammonia, diluted 1:50. The precipitate is dissolved in 10 cm
of hot hydrochloric acid, diluted 1:1, the filter carefully washed with hot water into a glass, where he conducted the deposition, and then perform the deposition and dissolution of hydroxides.
The solution was transferred to volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.
Depending on the iron content in the sample taken aliquot part of the solution in accordance with the table.5.
Table 5
| Mass fraction of iron, % |
Aliquota part of the solution, see |
The weight of the portion corresponding to aliquote part of the solution, g |
| To 0.05 |
- | The entire solution |
| SV. 0.05 to 0.1 |
50 | 0,5 |
| «Of 0.1» to 0.25 |
20 | 0,2 |
| «0,25» 0,5 |
10 | 0,1 |
| «0,5» 1 |
5 | 0,05 |
Aliquot part of the solution is placed in a volumetric flask with a capacity of 100 cmand dilute with water to 50 cm
(manganese bronze add 2cm
of a solution of hydrochloric acid hydroxylamine). After 2 minutes add 15 cm
sulfosalicylic acid solution, neutralized with ammonia, diluted 1:1, until a stable yellow color and add 3−4 cm
of ammonia in excess. The solution was then topped to the mark with water and mix. Optical density of the solution measured on a spectrophotometer in a cuvette length of 1 cm at
=425 nm or photoelectrocolorimeter with a purple filter (
=400 nm) in a cell 2 cm long.
Solution comparison is the solution of the control experiment through all stages of the analysis.
5.3.2. For silicon bronze
The sample of bronze with a weight of 1 g was placed in a platinum Cup and dissolved by heating in 10 cmof nitric acid and 2−3 cm
hydrofluoric acid. After dissolution, the sample solution was cooled, add 10 cm
sulphuric acid diluted 1:1, and evaporated until a white smoke of sulfuric acid. The Cup is cooled, carefully washed the walls of the Cup with water and dissolve salt in the water when heated.
The solution was transferred to a beaker with a capacity of 250 cm, dilute with water to 150 cm
, add 5 cm
of a solution of alum alimohammadian and further analysis are as indicated in claim
5.3.3. For lead bronze
The sample of bronze with a weight of 1 g was placed in a beaker with a capacity of 250 cm, cover with a watch glass and dissolved by heating in 15 cm
of nitric acid, diluted 1:1. After dissolution of the sample and remove the oxides of nitrogen by boiling and the solution was transferred to volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
Depending on the iron content in the sample taken aliquot part in accordance with the table.5 in a beaker with a capacity of 250 cm, add 10 cm
boiled nitric acid, diluted 1:1, add water to a volume of about 100 cm
and produce copper and lead by electrolysis on a platinum cylindrical electrode for 30 min. At the end of electrolysis the electrode is washed with a small amount of water into the same beaker, pour 5 cm
of alimohammadian solution of alum, the solution is heated to 60−70 °C and further analysis are as indicated in claim 5.3.1 .
5.4. Construction of calibration curve
In six volumetric flasks with a capacity of 100 cmpoured from microburette consistently 0; 1,0; 2,0; 3,0; 4,0 and 5,0 cm
standard solution B, dilute with water to 50 cm
and further analysis are as indicated in claim
Solution comparison is the solution not containing iron.
On the found values of optical densities build the calibration graph.
5.5. Processing of the results
5.5.1. Mass fraction of iron () in percent is calculated by the formula
where is the mass of iron was found in the calibration schedule g;
— the weight of the portion corresponding to aliquote part,
5.5.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.1.
(Changed edition, Rev. N 2).
5.5.3. The absolute discrepancies of the analysis results 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 specified in table.1.
5.5.4. Control of accuracy of analysis results is carried out according to claim
5.5.3,
6. ATOMIC ABSORPTION METHOD FOR DETERMINATION OF IRON
6.1. The essence of the method
The method is based on measuring the absorption of light by atoms of iron, formed during the introduction of the analyzed solution in the flame acetylene-air.
6.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with a radiation source for iron.
Nitric acid according to GOST 4461 and diluted 1:1.
Hydrochloric acid according to GOST 3118 and solutions 2 and 1 mol/DM.
A mixture of acids, is prepared as follows: the amount of nitric acid mixed with three volumes of hydrochloric acid.
Hydrofluoric acid according to GOST 10484.
Sulfuric acid according to GOST 4204, diluted 1:1.
Hydrogen peroxide according to GOST 10929.
Iron metal with a mass fraction of iron not less than 99.9%.
Standard solutions of iron.
Solution A, prepared as follows: 0.5 g of iron was dissolved with heating in 20 cmof hydrochloric acid with a few drops of hydrogen peroxide solution. Removed by boiling an excess of hydrogen peroxide, the solution is transferred into a measuring flask with volume capacity of 1000 cm
and top up with water to the mark.
1 cmof the solution contains 0.0005 g of iron.
Solution B is prepared as follows: 20 cmsolution And placed in a volumetric flask with a capacity of 100 cm
, add 10 cm
solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
1 cmof a solution contains 0.0001 g of iron.
6.3. Analysis
6.3.1. For bronzes with a mass fraction of tin and silicon up to 0.05%
A portion of the alloy mass, given in table.7, is placed in a beaker with a capacity of 250 cmand dissolved by heating in 10 cm
of nitric acid.
Table 7
| Mass fraction of iron, % | The mass of charge, g | The volume aliquote part of the solution, cm |
The volume of 2 mol/DM |
The volume of solution after dilution, see |
| From 0.01 to 0.2 |
1 | - | - | 100 |
| SV. 0,2 «2 |
1 | 10 | 10 | 100 |
| «2» 7 |
0,5 | 10 | 25 | 250 |
The solution was cooled, transferred to a volumetric flask with a capacity of 100 cmand top up with water to the mark. When the mass fraction of iron of more than 0.2% 10 cm
of the sample solution transferred to an appropriate volumetric flask (see table 7) add the specified in table.7 volume 2 mol/DM
hydrochloric acid solution and add water to the mark. Measure the atomic absorption of iron in the flame of acetylene-air at a wavelength of 248.3 nm or 372 in parallel with the calibration solutions.
(Changed edition, Rev. N 2).
6.3.2. For bronzes with a mass fraction of tin in excess of 0.05%
A portion of the alloy mass, given in table.7, is placed in a beaker with a capacity of 250 cmand dissolved by heating in 10 cm
of a mixture of acids. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm
, the side of the Cup rinse with a solution of 1 mol/DM
of hydrochloric acid and topped up to the mark with the same acid. When the mass fraction of iron of more than 0.2% 10 cm
of the sample solution transferred to an appropriate volumetric flask (see table 7) and then filled to the mark with a solution of 1 mol/DM
of hydrochloric acid.
Measure the atomic absorption of iron, as stated in claim
6.3.3. For bronzes with a mass fraction of silicon in excess of 0.05%.
A portion of the alloy mass, given in table.7, is placed in a platinum Cup and dissolved by heating in 10 cmof nitric acid and 2 cm
hydrofluoric acid. After dissolution, add 10 cm
sulphuric acid diluted 1:1, and the solution was evaporated until a white smoke of sulfuric acid. The residue is cooled, rinse the walls of the Cup with water and evaporated again until a white smoke of sulfuric acid. The residue is cooled and dissolved in water when heated. The solution was transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark. When the mass fraction of iron of more than 0.2% 10 cm
of the sample solution transferred to an appropriate volumetric flask (see table 7), made up of the specified in table.7 number of 2 mol/DM
hydrochloric acid solution and dilute to the mark with water. Measure the atomic absorption of iron, as stated in claim
6.3.4. Construction of calibration curve
In twelve of the thirteen volumetric flasks with a capacity of 100 cmis placed 0,5; 1,0; 2,0; 4,0; 6,0 and 8,0 cm
standard solution B, 2,0; 2,5; 3,0; 3,5; 4,0 and 5.0 cm in
standard solution A. In all flasks add 10 cm
of 2 mol/DM
hydrochloric acid solution and add water to the mark.
Measure the atomic absorption of iron, as stated in claim
According to the obtained results build a calibration curve.
6.4. Processing of the results
6.4.1. Mass fraction of iron () in percent is calculated by the formula
where is the concentration of iron was found in the calibration schedule, g/cm
;
— the volume of the final sample solution, cm
;
— the weight of the portion contained in the final volume of the solution,
6.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.1.
(Changed edition, Rev. N 2).
6.4.3. The absolute discrepancies of the analysis results 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 table.1.
6.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to State standard samples without tin bronzes, certified in the prescribed manner, or by comparing the results of analysis obtained by atomic absorption and photometric methods of analysis in accordance with GOST 25086.
6.4.3,
7. SULFOSALICYLATE PHOTOMETRIC METHOD FOR DETERMINATION OF IRON IN AN ACIDIC MEDIUM
7.1. The essence of the method
The method is based on formation of colored red-purple color of complex ferric iron with sulfosalicylic acid in an acidic medium in the measurement of the optical density of colored solution.
7.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Nitric acid according to GOST 4461 and diluted 1:1.
Hydrochloric acid according to GOST 3118 and diluted 1:1.
A mix of acids for dissolving 5 parts of concentrated nitric acid mixed with 3 parts of concentrated hydrochloric acid.
Tartaric acid according to GOST 5817, a solution of 50 g/DM.
Sulfosalicylic acid according to GOST 4478, solution 100 g/l; prepared as follows: 10 g of drug is dissolved in 60 cm
of water, neutralized with ammonia solution to pH 2−3 (universal indicator paper), filtered and diluted with water to 100 cm
.
Ammonia water according to GOST 3760.
Standard iron solution — according to claim 5.2.
Copper grade MO according to the GOST 859.
7.3. Analysis
For bronzes, in addition to siliceous and Sventevith.
The sample of bronze with a weight of 1 g when the mass fraction of iron from 0.01% to 0.1%; 0.5 g from 0.1% to 0.2%; 0.25 g, from 0.2% to 0.4% and 0.1 g — 0.1% to 1% is placed in a beaker with a capacity of 150 cm, add 8 cm
of the mixture of acids and dissolved first in cold and then when heated. After dissolution of the sample and remove the oxides of nitrogen by boiling for 1−1,5 min. the Solution was cooled, diluted with water to 40−50 cm
, add 5 cm
of a solution of tartaric acid and neutralized with ammonia solution prior to the deposition of basic salts of copper and immediately re-translate them into solution by careful addition with stirring hydrochloric acid (1:1). After the solids are dissolved, add 18 drops of an excess of the same acid. The solution was cooled, added to 6 cm
sulfosalicylic acid, transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix. Optical density of the solution is measured on a photoelectrocolorimeter with a green optical filter in a cuvette of 2 cm or on the spectrophotometer at a
=490 nm in a cuvette of 1 cm with a Solution of comparison is a sample of the same alloy conducted through the entire course of the analysis, but without the addition of sulfosalicylic acid.
7.4. Construction of calibration curve
Depending on the mass fraction of iron in glasses with a capacity of 150 cmis placed a portion of copper (from 0.1 to 1 g) are added sequentially 0; 1,0; 2,0; 4,0; 6,0; 8,0 and 10.0 cm
standard solution B iron and 8 cm
of the mixture of acids and then carry out the analysis, as specified in clause 7.3.
Solution comparison is the solution not containing iron, which is not a solution of sulfosalicylic acid.
On the found values of optical densities of solutions and their corresponding weight fractions of iron to build the calibration graph.
7.5. Processing of the results
7.5.1. Mass fraction of iron () in percent is calculated by the formula
where — mass fraction of iron was found in the calibration schedule g;
— the weight of the portion of alloy,
7.5.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.1.
7.5.3. The absolute discrepancies of the analysis results 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 table.1.
7.5.4. Control of accuracy of analysis results is carried out according to claim
