GOST 15027.4-77
GOST 15027.4−77 Bronze without tin. Methods for determination of manganese (with Amendments No. 1, 2)
GOST 15027.4−77
Group B59
INTERSTATE STANDARD
BRONZE WITHOUT TIN
Methods for determination of manganese
Non-tin bronze.
Methods for the determination of manganese
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
3. REPLACE GOST 15027.4−69
4. The standard fully complies ST SEV 1533−79
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Section number, paragraph, sub-paragraph |
| GOST 8.315−97 |
3.4.4.1 |
| GOST 84−76 |
2.2 |
| GOST 493−79 |
Chapeau |
| GOST 614−97 |
Chapeau |
| GOST 859−2001 |
3.2 |
| GOST 1277−75 |
2.2 |
| GOST 3118−77 |
2.2, 4.2, 5.2 |
| GOST 4197−74 |
3.2 |
| GOST 4204−77 |
2.2, 3.2, 4.2, 5.2 |
| GOST 4208−72 |
2.2 |
| GOST 4217−77 |
2.2 |
| GOST 4461−77 |
2.2, 3.2, 4.2, 5.2 |
| GOST 6008−90 |
2.2, 3.2, 4.2, 5.2 |
| GOST 6552−80 |
2.2, 3.2 |
| GOST 9656−75 |
3.2 |
| GOST 10484−78 |
2.2, 3.2, 4.2, 5.2 |
| GOST 10873−73 |
2.2, 4.2 |
| GOST 18175−78 |
Chapeau |
| GOST 20478−78 |
2.2 |
| GOST 20490−75 |
2.2 |
| GOST 25086−87 |
1.1, 2.4.4, 3.4.4, 4.4.4, 5.4.4 |
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 specifies the titrimetric method for the determination of manganese (at a mass proportion of manganese from 0.5% to 6%), a photometric method for the determination of manganese (at a mass fraction of manganese from 0.01% to 3.5%), potentiometric method for the determination of manganese (at a mass fraction of manganese from 8% to 16%) and atomic absorption method for the determination of manganese (at a mass fraction of manganese from 0.01% to 6%) in tin bronze according to GOST 18175, GOST and GOST 614 493.
(Changed edition, Rev. N 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. PERSULPHATE TITRIMETRIC METHOD FOR THE DETERMINATION OF MANGANESE
2.1. The essence of the method
The method is based on the oxidation of divalent manganese to pneumococcal neccersarily ammonium in an acidic medium in the presence of a catalyst of silver nitrate and the titration of pneumococcal of manganese with a solution of sodium servational to a bleaching solution or salt Mora establishment with potentiometric endpoint titration or visual with phenylanthranilic acid as indicator.
2.2. Apparatus, reagents and solutions
Potentiometer type LPM-60M.
Electrode platinum type ETPL-01M.
The electrode attoreny (prepared from silver chloride electrode EVL-1M, not the former in use, filling it with saturated solution of potassium nitrate).
Potassium nitrate according to GOST 4217, saturated solution.
Potassium permanganate according to GOST 20490, solution 0,01 mol/DM.
Hydrofluoric acid according to GOST 10484.
Sulfuric acid according to GOST 4204, and diluted 1:1 and 1:9.
Nitric acid according to GOST 4461 and diluted 1:1.
Orthophosphoric acid according to GOST 6552.
Ammonium neccersarily according to GOST 20478, a solution of 200 g/DM.
Silver nitrate according to GOST 1277, a solution of 10 g/DM.
Sodium carbonate crystal according to GOST 84 and solution 20 g/DM.
A mixture of acids, is prepared as follows: 525 cmof water is poured carefully in small portions with stirring, 100 cm
of concentrated sulfuric acid. The solution was cooled, poured 250 cm
of concentrated nitric acid and 125 cm
of phosphoric acid.
Manganese brand Мр0, Мр00 according to GOST 6008.
A standard solution of manganese; prepared as follows: 0.1 g of manganese dissolved in 10 cmof nitric acid, diluted 1:1, 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 and mix.
1 cmof the solution contains 0.001 g of manganese.
Chernovetskiy sodium (sodium thiosulfate), 0,0025 mol/DMsolution; prepared as follows: chernovetskogo of 1.30 g of sodium are dissolved in 1 DM
svejeprokipachenna and chilled water.
To stabilize the titer of the solution add 0.05 g of sodium carbonate. Titer of sodium thiosulfate establish a standard solution of manganese.
Phenylanthranilic acid, a solution of 4 g/DMis prepared as follows: 0.4 g phenylanthranilic acid are dissolved in 100 cm
of warm sodium carbonate solution. The solution was filtered and stored for not more than 10 days.
Salt Mora (double sulphate salt of divalent iron and ammonium) according to GOST 4208, 0,025 mol/DMsolution; prepared as follows: 19,608 g of Mohr salt dissolved in 100 cm
of sulphuric acid, diluted 1:9, and the same acid diluted to 1 DM
.
The titer determination of sodium thiosulfate
5 cmstandard solution of manganese is placed in a conical flask with a capacity of 250 cm
, flow 20 cm
of the mixture of acids and boil for 5 minutes to remove oxides of nitrogen. Then pour the 80 cm
water and 15 cm
of a solution of silver nitrate and 20 cm
of a solution of ammonium naternicola. The solution is heated for 15−20 minutes at low boil until complete destruction of the excess naternicola ammonium, as evidenced by the cessation of allocations of small bubbles of oxygen. Painted purple solution is rapidly cooled and titrated manganese acid 0,0025 mol/DM
solution of sodium thiosulfate until the disappearance of the pink color.
Titer of sodium thiosulfate (), expressed in grams of manganese per 1 cm
of a solution, calculated by the formula
where 0,005 — weight manganese, taken for titration, g; — the amount of sodium thiosulfate, spent on titration, sm
.
The installation of the titer of a solution of salt Mora for potentiometric titration
It is titrated with the sample solution (see p.2.3.2) add 10 cmof 0.01 mol/DM
solution of potassium permanganate and again potentiometric titrated with a solution of salt Mora to jump in the potential.
The installation of the titer of a solution of salt Mora for visual titration with acid phenylantranilic
In a conical flask with a capacity of 250 cmis placed 10 cm
sulfuric acid, diluted 1:1, 10 cm
of phosphoric acid, 100 CC
of water and 10.0 cm
of 0.01 mol/DM
solution of potassium permanganate.
The cooled mixture titrated with a solution of salt Mora to slightly pink coloring, then add 4−5 drops of solution phenylanthranilic acid and dotirovat before moving crimson color in light yellow.
The titer of a solution of salt Mora (), expressed in grams of manganese per 1 cm
of a solution, calculated by the formula
where 0,0005494 — weight manganese, corresponding to 1 cmof 0.01 mol/DM
solution of potassium permanganate, g;
— the volume of 0.01 mol/DM
of potassium permanganate solution taken for titration, cm
;
— the volume of salt solution Mora spent on titration, sm
.
2.3. Analysis
2.3.1. During the titration with sodium thiosulfate
2.3.1.1. For alloys with a mass fraction of silicon not more than 0.2%.
The weight of bronze depending on the content of manganese (tab.1) is placed in a conical flask with a capacity of 250 cm, and dissolved in 20 cm
of a mixture of acids when heated.
Table 1
| Mass fraction of manganese, % |
The mass of charge, g |
| From 0.5 to 1.0 |
0,5 |
| SV. Of 1.0 «to 3.0 |
0,2 |
| «To 3.0» and 6.0 |
0,1 |
The solution was boiled for 5 min to remove the oxides of nitrogen, then pour the 80 cmwater and 15 cm
of a solution of nitrate of silver, 20 cm
solution naternicola of ammonia, heat the solution to boiling and maintained at 90−95 °C for 15−20 min to complete the destruction of excess naternicola ammonium (until the termination of allocation of small bubbles of oxygen) and further analysis are as indicated in claim
2.3.1.2. For alloys with a mass fraction of silicon of more than 0.2%
Weighed bronze (see table.1) 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 complete dissolution of the alloy poured 10 cm
of sulphuric acid diluted 1:1, and evaporated until a white smoke of sulfuric acid. The residue is cooled, poured 30 cm
of water and heated to dissolve the salts and the solution transferred to a conical flask with a capacity of 250 cm
, rinsing the Cup 20 cm
of water. Then pour 10 cm
of phosphoric acid, 15 cm
of a solution of silver nitrate and 20 cm
of a solution of ammonium naternicola. The compound is weakly boiled for 15−20 min for complete destruction of excess naternicola ammonium (until the termination of allocation of small bubbles of oxygen).
Painted purple solution is rapidly cooled and titrated manganese acid 0,0025 mol/DMsolution of sodium thiosulfate to the disappearance of the pink.
ski.
2.3.2. When potentiometric titration with a solution of salt Mora
The weight of bronze in accordance with table.1 is placed in a beaker with a capacity of 250 cm, or platinum Cup. Dissolution of the sample and oxidation of manganese is carried out as indicated in the claims.2.3.1.1 and
2.3.3. By visual titration with a solution of salt Mora with phenylantranilic acid
Dissolution of the sample and oxidation of manganese is carried out as specified in the PP.2.3.1.1 and and titrated 0,025 mol/DM
solution of salt Mora to slightly pink coloring, then add 4−5 drops of solution phenylanthranilic acid and continue to titrate until the colour from crimson to light yellow.
2.4. Processing of the results
2.4.1. Mass fraction of manganese () in percent is calculated by the formula
where is the volume of sodium thiosulfate (or salt Mora), spent on titration, sm
;
the titer of the sodium thiosulfate (or salt Mora) for manganese, g/cm
;
— the weight of the portion,
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.2.
Table 2
| Mass fraction of manganese, % |
|
|
| From 0.01 to 0.03 |
0,003 | 0,007 |
| SV. Of 0.03 «to 0.10 |
0,006 | 0,01 |
| «To 0.10» to 0.25 |
0,01 | 0,02 |
| «0,25» 0,50 |
0,02 | 0,05 |
| «0,50» 1,2 |
0,04 | 0,1 |
| From 1.2 «to 2.5 |
0,06 | 0,1 |
| SV. The 2.5 «and 6.0 |
0,1 | 0,2 |
| An «8.0 «to 12.0 |
0,2 | 0,5 |
| «12,0» 16,0 |
0,3 | 0,7 |
(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 specified in table.2.
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 or atomic absorption method in accordance with GOST 25086.
2.4.3,
3. PERIODITY PHOTOMETRIC METHOD FOR THE DETERMINATION OF MANGANESE
3.1. The essence of the method
The method is based on the oxidation of divalent manganese to pneumococcal in an acidic medium with potassium periodate and measurement of the resulting purple color of the permanganate ion.
3.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Nitric acid according to GOST 4461, diluted 1:1.
Sulfuric acid according to GOST 4204, diluted 1:1.
Hydrofluoric acid according to GOST 10484.
Orthophosphoric acid according to GOST 6552.
Boric acid according to GOST 9656, saturated solution; prepared as follows: 60 g boric acid dissolve in 1 DMof hot water and after dissolution was cooled to room temperature.
A mixture of acids, is prepared as follows: 100 cmhydrofluoric acid are added to 900 cm
saturated solution of boric acid and mix well (solution stored in a plastic container).
Distilled water containing no reducing substances; prepared as follows: to 1 DMof water add 10 cm
sulphuric acid diluted 1:1, the solution is heated to 80 °C, add a few crystals of potassium jednolitego and boil for 5−10 minutes, then cooled.
Cognately potassium (potassium periodate).
Sodium atomistically according to GOST 4197, a solution of 50 g/DM.
Copper marks M1, M0 or M00 according to the GOST 859.
Manganese brand Мр00 according to GOST 6008.
A standard solution of manganese; prepared as follows: 0.1 g of manganese dissolved in 10 cmof nitric acid, diluted 1:1, and boil to remove oxides of nitrogen. The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix well.
1 cmof the solution contains 0.0001 g Margan
CA.
3.3. Analysis
3.3.1. For bronzes with a mass fraction of tin in excess of 0.05% and a mass fraction of silicon, more than 0.01% of
The weight of bronze weighing 0.5 g were placed in a glass with a capacity of 250 cm, add 15 cm
of the mixture of acids, 15 cm
water and 15 cm
of concentrated nitric acid and 5 cm
of phosphoric acid. First, dissolve without heating, and then heated to a temperature of 80−90 °C, until complete dissolution and removal of nitrogen oxides. When the mass fraction of manganese from 0.01% to 0.2% for the analysis using the full solution, but for the mass concentration of manganese in excess of 0.2% solution transferred to a volumetric flask with a capacity of 100 cm
and then filled to the mark with water. Aliquot part of the solution (see table.2A) is placed in a beaker with a capacity of 100 cm
, add the indicated volumes of nitric and phosphoric acids (see table.2A) and remove the oxides of nitrogen by boiling. Solution add water to a volume of 50 cm
, was added 0.3 g of potassium ionacollege, heated to boiling and boil for 5 minutes and Then the solution continued to heat for 15−20 min in a water bath at 80−90 °C., 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 is measured on a photoelectrocolorimeter with a green optical filter at a wavelength of 540 nm or on a spectrophotometer at a wavelength of 528 nm in a cuvette length of 1 cm.
Table 2A
| Mass fraction of manganese, % | The volume aliquote part of the solution, cm |
The volume of the added acid, see | |
| nitrogen |
phosphoric | ||
| From 0.01 to 0.2 |
All | - | - |
| SV. 0,2 «to 2,0 |
10 | 13 | 4,5 |
| «2,0» 3,0 |
5 | 15 | 5 |
As a solution comparison, using part of the solution of the same samples in which pneumococcal manganese reduced to divalent by the addition dropwise of a solution of sodium attestatio to bleaching.
3.3.2. For bronzes with a mass fraction of tin is less than 0.05% and silicon less than 0.01%
The weight of bronze weighing 0.5 g were placed in a glass with a capacity of 250 cmadd 30 cm
water and 15 cm
of concentrated nitric acid and 5 cm
of phosphoric acid. Then do as stated in claim
3.3.3. Construction of calibration graphs
3.3.3.1. Construction of calibration curve for bronzes with a mass fraction of tin in excess of 0.05 percent and silicon in excess of 0.01%.
Nine of cups with a capacity of 250 cmis placed 0.5 g of copper, add 15 cm
of the mixture of acids, at 15 cm
of water, 15 cm
of concentrated nitric acid and 5 cm
of phosphoric acid and dissolved without heating, and then by heating and removing the nitrous oxide by boiling. In eight glasses injected 0,5; 1,0; 2,0; 4,0; 6,0; 8,0; 10,0 and 12.0 cm
standard solution of manganese, add 0.3 g of potassium jednolitego and further analysis is carried out as specified in clause
3.3.3.2. Construction of calibration curve for bronzes with a mass fraction of tin is less than 0.05% and silicon less than 0.01%.
Nine of cups with a capacity of 250 cmis placed 0.5 g of copper, add 30 cm
of water, 15 cm
of concentrated nitric acid and 5 cm
of phosphoric acid and then act as described in section
3.3
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,
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.2.
(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.2.
3.4.4. 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, by comparing the results of analysis obtained by titrimetric and atomic absorption methods or by a method of additives in accordance with GOST 25086.
3.4.3,
4. POTENTIOMETRIC METHOD FOR THE DETERMINATION OF MANGANESE
4.1. The essence of the method
The method is based on potentiometric titration of manganese (II) in acidic medium in the presence of fluoride ion solution of potassium permanganate.
4.2. Apparatus, reagents and solutions
A potentiometer with a platinum and calomel electrodes.
Nitric acid according to GOST 4461 and diluted 1:1.
Hydrochloric acid according to GOST 3118.
Sulfuric acid according to GOST 4204, diluted 1:1 and 1:9.
Hydrofluoric acid according to GOST 10484.
A mixture of acids, is prepared as follows: the amount of nitric acid mixed with three volumes of hydrochloric acid.
Ammonium sulfate according to GOST 10873, a solution of 100 g/DM.
The sodium fluoride.
Manganese GOST 6008 with a mass fraction of manganese is not less than 99.9%.
A standard solution of manganese; prepared as follows: 1 g of manganese dissolved in 10 cmof nitric acid, diluted 1:1, and boil to remove oxides of nitrogen.
The solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.
1 cmof the solution contains 0.001 g of manganese.
Potassium permanganate according to GOST 20490, solution 0,02 mol/DM, prepare fiksanala or 3.27 g of potassium permanganate dissolved in 1000 cm
of water; the solution is allowed to stand from 10 to 15 days, then filtered through an asbestos filter in a bottle of dark glass.
The titer determination of potassium permanganate solution.
50 cmstandard solution of manganese is placed in a beaker with a capacity of 250 cm
, add 10 cm
sulphuric acid diluted 1:1, and the solution is evaporated to release a thick white smoke of sulfuric acid. The solution was cooled, rinse the walls of the glass with water and again evaporated to release a thick white smoke of sulfuric acid. The residue is dissolved in 10 cm
of sulphuric acid, diluted 1:9, add 10 cm
of a solution of ammonium sulfate and add water to a volume of about 100 cm
. To the cooled solution was added to 5−7 g of sodium fluoride and potentiometric titrated solution of potassium permanganate until the jump of the potential. The titer of a solution of potassium permanganate (
), expressed in grams of manganese per 1 cm
, is calculated by the formula
where is the mass of manganese, was taken for titration, g;
— the volume of potassium permanganate solution consumed for titration, sm
.
4.3. Analysis
4.3.1. For bronzes with a mass fraction of silicon to 0.1%
The weight of bronze weighing 0.5 g were placed in a glass with a capacity of 250 cmand dissolved in 10−20 cm
of the mixture of acids when heated. After dissolution, add 10 cm
sulphuric acid diluted 1:1, and evaporate the solution until a white smoke of sulfuric acid.
The solution was cooled, rinse the walls of the glass with water and evaporated again until a white smoke of sulfuric acid. The precipitate is dissolved in 10 cmof sulphuric acid, diluted 1:9, add 10 cm
of a solution of ammonium sulfate and add water to a volume of about 100 cm
. To the cooled solution was added to 5−7 g of sodium fluoride and potentiometric titrated solution of potassium permanganate until the jump of the potential.
4.3.2. For bronzes with a mass fraction of silicon than 0.1%
The weight of bronze weighing 0.5 g is placed in a platinum Cup and dissolved in 10 cmof nitric acid, diluted 1:1, and 2−3 cm
hydrofluoric acid when heated. After dissolution, add 10 cm
sulphuric acid diluted 1:1, and evaporated until a white smoke of sulfuric acid. The solution was cooled, rinse the walls of the Cup with water and evaporated again until a white smoke of sulfuric acid. The residue is dissolved in 10 cm
of sulphuric acid, diluted 1:9, add 10 cm
of a solution of ammonium sulfate and the solution was transferred to a beaker with a capacity of 250 cm
, top up with water to a volume of about 100 cm
and further analysis is carried out as specified in clause 4.3.1
.
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
;
the titer of a solution of potassium permanganate for manganese, g/cm
;
— the weight of the portion,
4.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
4.4.3. 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.2.
4.4.4. 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 of the obtained photometric and atomic absorption methods or by a method of additives in accordance with GOST 25086.
4.4.3,
5. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF MANGANESE
5.1. The essence of the method
The method is based on measuring the absorption of light by atoms of manganese formed during the introduction of the analyzed solution in the flame acetylene-air.
5.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with a radiation source for manganese.
Nitric acid according to GOST 4461 and diluted 1:1.
Hydrochloric acid according to GOST 3118 and diluted 1:1 and solution 2 mol/land 1 mol/DM
.
A mixture of acids, is prepared as follows: one volume of concentrated nitric acid mixed with three volumes of concentrated hydrochloric acid.
Hydrofluoric acid according to GOST 10484.
Sulfuric acid according to GOST 4204, diluted 1:1.
Manganese GOST 6008 with a mass fraction of manganese is not less than 99.9%.
Standard solutions of manganese.
Solution A, prepared as follows: 0.5 g of manganese dissolved by heating in 20 cmof hydrochloric acid diluted 1:1, the solution was cooled, transferred to 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 manganese.
Solution B is prepared as follows: 20 cmsolution And placed in a volumetric flask with a capacity of 100 cm
, add 10 cm
of 2 mol/DM
hydrochloric acid solution and add water to the mark.
1 cmof a solution contains 0.0001 g of Marga
ntsa.
5.3. Analysis
5.3.1. For bronzes with a mass fraction of tin is less than 0.05% and silicon less than 0.01%.
A portion of the bronze mass, given in table.4, is placed in a beaker with a capacity of 250 cm, and dissolved in 10 cm
of nitric acid, diluted 1:1. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark. For the mass concentration of manganese in excess of 0.15% of transfer 10 cm
of this solution into an appropriate volumetric flask (see table 4) add the specified in table.4 volume 2 mol/DM
hydrochloric acid solution and add water to the mark.
Table 4
| Mass fraction of manganese, % | 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 0.15 |
1 | All | - | 100 |
| SV. Of 0.15 «to 1.5 |
1 | 10 | 10 | 100 |
| Is 1,5 6,0 |
0,5 | 10 | 25 | 250 |
Measure the atomic absorption of manganese in the flame acetylene-air at a wavelength of 279.5 nm or of 280.1 in parallel with the calibration solutions.
5.3.2. For bronzes with a mass fraction of tin in excess of 0.05%
A portion of the bronze mass, given in table.4, 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
, rinse walls of beaker with a solution of 1 mol/DM
of hydrochloric acid and topped up to the mark with the same acid. For the mass concentration of manganese in excess of 0.15% of transfer 10 cm
of this solution into an appropriate volumetric flask (see table 4) and top up to the mark of 1 mol/DM
hydrochloric acid solution.
Measure the atomic absorption of manganese, as specified in clause
5.3.3. For bronzes with a mass fraction of silicon, more than 0.01% of
A portion of the bronze mass, given in table.4, is placed in a platinum Cup and dissolved by heating in 10 cmof nitric acid, diluted 1:1, and 2 cm
hydrofluoric acid.
After dissolution, add 10 cmsulphuric 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. For the mass concentration of manganese in excess of 0.15% of transfer 10 cm
of the solution into an appropriate volumetric flask (see table 4) add the specified in table.4 volume 2 mol/DM
hydrochloric acid solution and add water to the mark.
Measure the atomic absorption of manganese, as specified in clause
5.3.4. Construction of calibration curve
In eleven of the twelve volumetric flasks with a capacity of 100 cmplaced 0,5; 1,0; 2,0; 4,0; 6,0; 8,0 cm
standard solution and 2,0; 2,5; 3,0; 3,5 and 4,0 cm
standard solution And manganese. To all flasks add 10 cm
of 2 mol/DM
hydrochloric acid solution and add water to the mark.
Measure the atomic absorption of manganese, as specified in clause
5.4. Processing of the results
5.4.1. Mass fraction of manganese () in percent is calculated by the formula
where is the concentration of manganese was found in TradeRoom graphics, cm
;
— the volume of the final sample solution, cm
;
— the weight of the portion contained in the final volume of the sample solution,
5.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
5.4.3. 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.2.
5.4.4. 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 or titrimetric methods in accordance with GOST 25086.
5.4.3,
