GOST 23859.5-79
GOST 23859.5−79 heat-resistant Bronze. Methods for determination of iron (with Amendments No. 1, 2)
GOST 23859.5−79
Group B59
INTERSTATE STANDARD
BRONZE HIGH-TEMPERATURE
Methods of iron determination
Bronze fire-resistance. Methods for the determination of iron
AXTU 1709
Date of introduction 1981−01−01
Resolution of the USSR State Committee for standards, dated 16 October 1979, N 3937 time of the introduction set with 01.01.81
Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)
EDITION with Amendments No. 1, 2 approved in June 1985, March 1990 (IUS 9−85, 7−90).
This standard establishes photometric methods for determination of iron (at mass fraction of iron from 0.01 to 0.08%) in high-temperature copper alloys
(Changed edition, Rev. N 1, 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086−87 with the addition of a GOST 23859.1−79, sec. 1.
(Changed edition, Rev. N 2).
2. PHOTOMETRIC METHOD FOR DETERMINATION OF IRON WITH THE USE OF 1,10-PHENANTHROLINE OR 2,2'-DIPYRIDYL
2.1. The essence of the method
The method is based on the preliminary allocation of iron by coprecipitation with the aluminum hydroxide and the formation of iron (II) colored complex with 1,10-phenanthroline or 2,2'-dipyridil at pH 5 in the presence of hydroxylamine hydrochloric acid and measuring the optical density of the solution.
2.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Sulfuric acid GOST 4204−77 and diluted 1:1.
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Nitric acid GOST 4461−77 diluted 1:1.
Acetic acid GOST 61−75.
Ammonia according to GOST 3760−79 diluted 1:1 and 1:100.
Sodium acetate according to GOST 199−78.
Rectified ethyl alcohol GOST 18300−87.
Phenolphthalein on the other 6−09−5360−87, solution in ethyl alcohol, 1 g/DM
.
Ammonium-aluminum sulphate (aluminum-ammonium alum) according to GOST 4238−77, a solution of 10 g of alum is dissolved in 1 DMof water with the addition of 10 cmof concentrated sulfuric acid.
Hydroxylamine hydrochloric acid according to GOST 5456−79, a solution of 10 g/DM, freshly prepared.
1,10-phenanthrolin hydrochloride, a solution of 1.5 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.
2,2'-dipyridyl, a solution of 1.5 g of 2,2'-dipyridyl dissolved in a small amount of water when heated 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 cmof acetic acid, filter and add water to 1 DM.
A mixture of freshly prepared reagent: one part of a solution of hydroxylamine hydrochloric acid is mixed with one part of the 1,10-phenanthroline or 2,2'-dipyridyl and with three parts of buffer solution.
Standard solutions of iron.
Solution A. 0,5025 g standard sample N 126 low carbon steel or iron carbonyl dissolved in 20 cmof nitric acid. 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. 10 cmof the solution And placed in a volumetric flask with a capacity of 100 cm, top up to the mark with water and mix. 1 cmof a solution of 0.00005 g contains iron.
(Amended And
ZM. N 1).
2.3. Analysis
2.3.1. For bronzes containing chromium
The sample of bronze with a weight of 1 g at an iron content of from 0.01 to 0.03% and 0.5 g for the mass concentration of iron is from 0.02 to 0.08% was placed in a platinum Cup, add 10 cmof nitric acid and 2−3 cmhydrofluoric acid and dissolved by heating. After dissolution, the sample solution was cooled, add 10 cmsulphuric acid diluted 1:1 and evaporated until a white smoke of sulfuric acid. The Cup is cooled, gently rinse the walls of the Cup with water and dissolve residue in water when heated. The solution was transferred to a beaker with a capacity of 250 cm, is diluted with water to a volume of 150 cm, add 5 cmof a solution of aluminum ammonium alum 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, a glass and the precipitate washed with hot ammonia solution, diluted 1:100. The precipitate is dissolved in 10 cmof hot hydrochloric acid in a beaker which carried out the deposition, the filter carefully washed with hot water and again carried out the precipitation of the hydroxide. The precipitate was filtered off, washed with hot ammonia solution, diluted 1:100, dissolved in 10 cmof hot hydrochloric acid and the filter washed with hot water into a glass, where he conducted the deposition. Heated to dissolve the precipitate, the solution is evaporated to a volume of 40 cm, transferred to a volumetric flask with a capacity of 100 cmand top up with water to 50 cm. The solution was then neutralized with ammonia, diluted 1:1, phenolphthalein, add 1 cmof hydrochloric acid and 25 cmof a mixture of reagents, made up to the mark with water and mix. After 30 min measure the optical density on the spectrophotometer in a cuvette with a thickness of absorbing layer 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, 2).
2.3.2. For bronzes not containing chromium
The weight of bronze weighing 0.5 g were placed in a glass with a capacity of 250 cm, cover with a watch glass, add 15 cmof nitric acid and carefully dissolved by heating. The glass solution was cooled, rinse the walls of the glass beaker and a small amount of water and the solution diluted with water to a volume of 150 cm. Add 5 cmof a solution of aluminum ammonium alum and then received, as indicated in claim 2.3.1.
(Changed edition, Rev. N 1).
2.4. Construction of calibration curve
In a volumetric flask with a capacity of 100 cmflow consistently 0; 0,5; 1,0; 2,0; 4,0; 6,0; 8,0 cmof a solution of iron, add water to 50 cm, pour 2−3 drops of solution of phenolphthalein and neutralized with ammonia, diluted 1:1. Further analysis are as indicated in claim 2.3.1. Solution comparison is the solution not containing iron.
(Changed edition, Rev. N 1, 2).
2.5. Processing of the results
2.5.1. 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,
2.5.2. Discrepancies in the results of three parallel definitions should not exceed the values permitted by the divergence 
(the rate of convergence), calculated according to the formula
,
where — mass fraction of iron in the alloy, %.
(Changed edition, Rev. N 2).
2.5.3. 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 calculated according to the formula
,
where — mass fraction of iron in the alloy, %.
2.5.4. Control of accuracy of analysis results is carried out according to State standard samples of heat-resistant (CR) bronze or supplements method, or comparison of results obtained by atomic absorption method in accordance with GOST 25086−87.
2.5.3, 2.5.4. (Added, Rev. N 2).
3. PHOTOMETRIC METHOD FOR DETERMINATION OF IRON WITH THE USE OF SULFOSALICYLIC ACID
3.1. 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.
3.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Nitric acid GOST 4461−77 diluted 1:1.
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Sulfuric acid GOST 4204−77, diluted 1:1.
Sulfosalicylic acid according to GOST 1478−93, a solution of 200 g/DM.
Ammonia water according to GOST 3760−79 diluted 1:1 and 1:100.
Alum alimohammadian according to GOST 4238−77, a solution of 10 g of alum is dissolved in 1 DMof water with the addition of 10 cmof concentrated sulfuric acid.
Standard solutions of iron.
Solution A. 1,005 g of a standard sample of low carbon steel N 126 dissolved in 20 cmof nitric acid. 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.
Solution B. 10 cmof the solution And transferred to a volumetric flask with a capacity of 100 cm, top up to the mark with water and mix. 1 cmof a solution contains 0.0001 g jelly
for.
3.3. Analysis
3.3.1. For bronzes containing chromium
The sample of bronze with a weight of 1 g was placed in a platinum Cup, add 10 cmof nitric acid, 2−3 cmhydrofluoric acid and dissolved by heating. The solution is cooled, add 10 cmsulphuric acid diluted 1:1 and evaporated until a white smoke of sulfuric acid. The Cup is cooled, gently rinse the walls of the Cup with water and dissolve residue in water when heated.
The solution was transferred to a beaker with a capacity of 250 cm, is diluted with water to a volume of 150 cm, add 5 cmof a solution of aluminum ammonium alum and ammonia, 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 separated precipitate was filtered off on a medium density filter, a glass and the precipitate washed with hot ammonia solution, diluted 1:50. The precipitate is dissolved in 10 cmof hot hydrochloric acid in a glass, where he conducted the deposition, and again carried out the precipitation of the hydroxide.
The precipitate was filtered off, washed with hot ammonia solution, diluted 1:100, dissolved in 10 cmof hot hydrochloric acid and the filter washed with hot water into a glass, where he conducted the deposition. Heated to dissolve the precipitate, the solution is evaporated to a volume of 20 cm, transferred to a volumetric flask with a capacity of 100 cmand top up with water to 30 cm.
Then add 15 cmsulfosalicylic acid solution, neutralized with ammonia, diluted 1:1, until a stable yellow color, add an excess of ammonia 3−4 cm, made up to the mark with water and measure the optical density of the solution on the spectrophotometer in a cuvette with a thickness of absorbing layer 1 cm at 425 nm or photoelectrocolorimeter with a purple filter in a cuvette with a thickness of the absorbing layer 2 see Solution comparison is the solution of the control
experience.
3.3.2. For bronzes not containing chromium
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, add 15 cmof nitric acid and dissolved by heating. The glass solution was cooled, rinsed the glass and the side of the Cup a small amount of water and dilute with water to 150 cm. Add 5 cmof a solution of aluminum ammonium alum and then received, as indicated in paragraph 3.3.1.
3.4. Construction of calibration curve
7 volumetric flasks with a capacity of 100 cmflow consistently 0; 1,0; 2,0; 3,0; 4,0; 5,0; 6,0; 8,0 cmstandard solution of iron diluted with water to a volume of 30 cmand then received, as indicated in paragraph 3.3.1. Solution comparison is the solution not containing iron.
(Changed edition, Rev. N 2).
3.5. Processing of the results
3.5.1. 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,
3.5.2. Discrepancies in the results of three parallel definitions should not exceed the values permitted by the divergence (the rate of convergence), calculated as specified in claim 2.5.2.
(Changed edition, Rev. N 2).
3.5.3. 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), calculated as specified in claim 2.5.3.
3.5.4. Control of accuracy of analysis results is carried out as specified in clause 2.5.4.
3.5.3, 3.5.4. (Added, Rev. N 2).
