GOST 6689.4-92
GOST 6689.4−92 Nickel, alloys Nickel and copper-Nickel. Methods for determination of zinc
GOST 6689.4−92
Group B59
STATE STANDARD OF THE USSR
NICKEL, ALLOYS NICKEL AND COPPER-NICKEL
Methods for determination of zinc
Nickel, nickel and copper-nickel alloys. Methods for the determination of zinc
AXTU 1709
Date of introduction 1993−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of metallurgy of the USSR
DEVELOPERS
V. N. Fedorov, B. P. Krasnov, Y. M. Leybov, A. N. Bulanova, I. A. Vorobyova, L. V. Morea
2. APPROVED AND promulgated by the Decree of Committee of standardization and Metrology of the USSR from
3. REPLACE GOST 6689.4−80
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Paragraph number section |
| GOST 8.315−91 |
2.4.3; 3.5.3; 4.5.3; 5.4.3 |
| GOST 61−75 |
2.2; 3.2 |
| GOST 454−76 |
3.2; 4.2 |
| GOST 492−73 |
Chapeau |
| GOST 849−70 |
5.2 |
| GOST 859−78 |
5.2 |
| GOST 1277−75 |
3.2; 4.2 |
| GOST 2567−89 |
3.2; 4.2 |
| GOST 3118−77 |
2.2; 3.2; 4.2; 5.2 |
| GOST 3640−79 |
2.2; 3.2; 4.2; 5.2 |
| GOST 3760−79 |
2.2; 3.2; 4.2 |
| GOST 3773−72 |
4.2 |
| GOST 4139−75 |
3.2; 4.2 |
| GOST 4204−77 |
3.2; 4.2; 5.2 |
| GOST 4207−75 |
4.2 |
| GOST 4217−77 |
2.2 |
| GOST 4233−77 |
3.2; 4.2 |
| GOST 4328−77 |
3.2 |
| GOST 4461−77 |
2.2; 3.2; 4.2; 5.2 |
| GOST 4463−76 |
2.2 |
| GOST 4658−73 |
4.2 |
| GOST 6344−73 |
2.2 |
| GOST 6689.1−92 |
Sec. 1 |
| GOST 9285−78 |
4.2 |
| GOST 9293−74 |
4.2 |
| GOST 10484−78 |
4.2; 5.2 |
| GOST 10652−73 |
2.2; 3.2 |
| GOST 19241−80 |
Chapeau |
| GOST 19522−74 |
2.2 |
| GOST 20015−88 |
2.2 |
| GOST 20301−74 |
3.2; 4.2 |
| GOST 20848−75 |
2.2 |
| GOST 25086−87 |
Section.1; 2.4.3; 3.5.3; 4.5.3; 5.4.3 |
| GOST 27068−86 |
2.2 |
This standard establishes titrimetric complex metric methods for the determination of zinc (at a mass fraction of zinc from 17 to 30%), polarographic (with mass fraction from 0.1 to 0.6%) and atomic absorption (at a mass fraction of from 0.001 to 0.6%) methods for determination of zinc in Nickel and copper-Nickel alloys according to GOST 492* and GOST 19241.
________________
* On the territory of the Russian Federation GOST 492−2006. — Note the manufacturer’s database.
1. GENERAL REQUIREMENTS
General methods the methods of analysis according to GOST 25086 with the addition of sec. 1 GOST 6689.1.
2. EXTRACTION-TITRIMETRIC METHOD FOR THE DETERMINATION OF ZINC
2.1. The essence of the method
The method is based on complexometric titration of zinc after extraction separation in the form romanengo complex with methyl isobutyl ketone from hydrochloric acid solution containing thiourea and citrate ions to mask the deformity of the elements.
2.2. Reagents and solutions
Hydrochloric acid according to GOST 3118 and diluted 1:1 and 1:4.
Nitric acid according to GOST 4461.
A mixture of acid: 1 part concentrated nitric acid mixed with 3 parts of concentrated hydrochloric acid.
Acetic acid according to GOST 61.
Ammonia water according to GOST 3760.
Thiourea according to GOST 6344 and a solution of 50 g/DM.
Ammonium citrate according to GOST dvosemyanny 3653 and a solution of 400 g/DM.
Ammonium radamisty according to GOST 19522.
The masking reagent solution: 60 g of thiourea, 150 g Rodenstock ammonium and 100 g dvuhsektsionnogo ammonium citrate dissolved in 1 DMof water.
Wash solution: mix 250 cmof masking reagent solution, 250 cm
water and 25 cm
of hydrochloric acid (1:4).
Sodium fluoride according to GOST 4463, a solution of 5 g/DM.
Potassium fluoride according to GOST 20848, a solution of 500 g/DM.
Potassium nitrate according to GOST 4217.
Methyl isobutyl ketone.
Chloroform according to GOST 20015.
Chernovetskiy sodium (sodium thiosulfate) 5-water according to GOST 27068, a solution of 250 g/DM.
-Nitroso-a
-naphthol, a solution of 10 g/DM
acetic acid.
Selenology orange.
Indicator mixture: 0.1 g kylinalove orange mixed with 10 g of potassium nitrate and grind in a homogeneous mass.
Hexamethylenetetramine (hexamine).
Ethylenediamine-N, N, N', N'-tetraoxane acid, disodium salt, 2-water (Trilon B) according to GOST 10652, 0.05 mol/DMsolution; 18,612 g Trilon B dissolved in 500 cm
of water, the solution is placed in a volumetric flask with a capacity of 1 DM
and topped to the mark with water.
Zinc metal stamps C0 according to GOST 3640*.
______________
* On the territory of the Russian Federation GOST 3640−94, here and hereafter. — Note the manufacturer’s database.
Standard zinc solution: 1.0 g of zinc is dissolved in 30 cmof hydrochloric acid (1:1) solution is transferred into 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 zinc.
2.2.1. The installation of the mass concentration of the solution Trilon B for zinc
50 cmstandard solution of zinc is placed in a separating funnel with a capacity of 250 cm
, add ammonia solution until the appearance of unfading light haze.
Add 5 cmof hydrochloric acid (1:4) and then do as described in claim
The mass concentration of the solution Trilon B, expressed in g/cmzinc, calculated by the formula
0,05 where is the mass of zinc, taken for titration, g; — volume of solution Trilon B, spent on titration, sm
.
2.3. Analysis
2.3.1. For alloys containing less than 0.03% of cobalt
A sample of alloy weighing 0.5 g were placed in a glass with a capacity of 300 cm, adding 25 cm
of a mixture of acid, cover with watch glass, glass or plastic plate and dissolved by heating.
Glass (or plate) and the side of the Cup then rinsed with water, the solution was boiled to remove oxides of nitrogen, cooled, placed in a volumetric flask with a capacity of 100 cmand then filled to the mark with water.
Aliquot part of the solution was 10 cmplaced in a separating funnel with a capacity of 250 cm
, top up with water to 50 cm
and drop by drop add ammonia solution until the appearance of unfading light haze.
Then add 5 cmof hydrochloric acid (1:4) and with vigorous stirring injected 50 cm
of a solution of a mixture of masking agents. Enter 50 cm
of methyl isobutyl ketone and shake vigorously for 2 min. After phase separation, the aqueous phase is placed in a second separatory funnel with a capacity of 250 cm
and repeat the extraction with 20 cm
of methyl isobutyl ketone. The aqueous phase is discarded, and the organic combine with extracts in the first separating funnel. Vacant second separatory funnel rinse a 20 cm
wash solution, and then the same flushing solution was washed with the combined extracts in the first separating funnel.
After phase separation, the aqueous phase is removed and the organic was placed in a beaker with a capacity of 400 cm, separating funnel rinse the 25 cm
hydrochloric acid (1:4), and then 100 cm
of water and added to the organic phase. To the mixture add 20 cm
of a solution of sodium fluoride, 20 cm
of a solution of thiourea and establish a pH of 5.0 to 5.2 on indicator paper «Rfat» the addition of urotropine, and then add on the tip of a spatula 0.1 g of indicator mixture and titrate the zinc solution of Trilon B before the transition red-violet color to yellow. Before the end of the titration control the pH of the solution and, if necessary, add hexamine or hydrochloric acid (1:4) to establish a pH of 5.0 to 5.2 on indicator paper «Rfat». Near the end point of the titration solution Trilon B added a small
and portions.
2.3.2. For alloys containing more than 0.03% of cobalt
Preparation for the analysis carried out according to p. placed in a separating funnel with a capacity of 250 cm
, add water up to 50 cm
and drop by drop ammonia solution to a light haze. Then add 5 cm
of twosemester solution of citrate of ammonium, 15 cm
of sodium thiosulfate, 1 cm
of a solution of potassium fluoride, 2 cm
of mortar
, nitroso-
-naphthol funnel and intensively shaken for 1.5 min. Add 25 cm
of chloroform and shake for 3 min. After phase separation, the organic phase is discarded, and the aqueous phase is added 20 cm
of chloroform and repeat the extraction. After phase separation, the organic phase is discarded and water is added to 50 cm
of masking reagent solution, and further receives, as specified in clause
2.3.1.
2.5*. Processing of the results
________________
* Numbering corresponds to the original. — Note the manufacturer’s database.
2.4.1. Mass fraction of zinc () in percent is calculated by the formula
where — volume of solution Trilon B, used for titration, cm
;
— mass concentration of the solution Trilon B, g/cm
;
— the weight of the portion corresponding to aliquote part of the solution,
2.4.2. Discrepancies in the results of three parallel measurements (rate of convergence) and the results of the two tests
(index of reproducibility) shall not exceed the values of permissible differences given in table.1.
Table 1
| Mass fraction of zinc, % |
The allowable divergence, % | |
| From 17 to 20 incl. |
0,2 |
0,3 |
| SV. 20 «30 « |
0,3 |
0,4 |
2.4.3. Control of accuracy of analysis results is carried out according to State standard samples (GSO) or industry standard sample (CCA) or by standard samples of the enterprise (SOP) of copper-Nickel alloys, approved under GOST 8.315* in accordance with GOST 25086.
________________
* On the territory of the Russian Federation GOST 8.315−97, here and hereafter. — Note the manufacturer’s database.
3. TITRIMETRIC METHOD FOR THE DETERMINATION OF ZINC WITH THE SEPARATION OF THE ZINC ON THE ANION
3.1. The essence of the method
The method is based on complexometric titration of zinc after its separation on strong-base anion exchanger.
3.2. Apparatus, reagents and solutions
Glass ion-exchange column 15 mm in diameter, with a height of 250−300 mm (as columns you can use a burette with a capacity of 50 cmwith a diameter of 12−15 mm).
Anion exchange resin an-31 or other anion-exchange resins of this group according to GOST 20301.
Nitric acid according to GOST 4461, diluted 1:1.
Hydrochloric acid according to GOST 3118, diluted 1:1, 1:20 and a solution of 2 mol/DM.
Sulfuric acid according to GOST 4204, diluted 1:1, 3:100.
Bromatologia acid according to GOST 2567.
Acetic acid according to GOST 61.
Bromine according to GOST 454.
Mix to dissolve the freshly prepared: 9 parts bromatological acid mixed with one part of bromine.
Sodium hydroxide according to GOST 4328, solution 50 and 100 g/DM.
Ammonia water according to GOST 3760 and diluted 1:5.
Sodium fluoride according to GOST 2871, a solution of 100 g/DM.
Sodium Chernovetskiy, a solution of 200 g/DM.
Buffer solution pH=5,796 cm
of acetic acid and 115 cm
of ammonia, dilute with water to 1000 cm
.
Selenology orange.
Sodium chloride according to GOST 4233 and a saturated solution.
The mixture kylinalove orange with sodium chloride in a ratio of 1:100.
Potassium rodanistye according to GOST 4139, a solution of 10 g/DM.
Silver nitrate according to GOST 1277, a solution of 10 g/DM.
Zinc GOST 3640 with a mass fraction of zinc not less than 99.9%.
Standard solution of zinc, 1 g of zinc is dissolved in 25 cmof hydrochloric acid (1:1) solution was evaporated to dryness, the dry residue dissolved in 100 cm
of hydrochloric acid (1:1), transferred to a measuring flask with volume capacity of 1000 cm
and topped to the mark with water.
1 cmof the solution contains 0.001 g of zinc.
Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid 2-water (Trilon B) according to GOST 10652, 0.01 mol/DM
solution.
3.2.1. The installation of the mass concentration of the solution Trilon B for zinc
50 cmstandard solution of zinc is placed in a conical flask with a capacity of 500 cm
, is diluted with water to 300 cm
, add about 0.1 g of a mixture kylinalove orange with sodium chloride, is neutralized with ammonia until the appearance of weakly violet colour, add 2.5 cm
of the solution servational sodium, 1 cm
of a solution of sodium fluoride, 10 cm
buffer solution and titrated with a solution of Trilon B till the color changes to yellow.
Mass concentration of the solution Trilon B (), expressed in g/cm
zinc, calculated by the formula
where is the mass of zinc, taken for titration, g;
— volume of solution Trilon B, spent on titration, sm
.
3.3. Preparation for assay
3.3.1. Preparation of chromatographic columns to work
50 g of anion exchange resin (fine fraction) was placed in a beaker with capacity of 500 cm, pour 400 cm
of saturated sodium chloride solution and kept for 24 h at room temperature. The solution is decanted and the resin was washed by decantation with hydrochloric acid (1:20) to complete the removal of iron (reaction with romanisti potassium). Then the resin is successively washed with sodium hydroxide solution 50 g/DM
, sodium hydroxide solution 100 g/DM
the complete removal of the chloride ion (reaction with silver nitrate), washed with water until a weakly alkaline reaction wash liquid and treated with three portions of 2 mol/DM
hydrochloric acid solution at 100 cm
each.
In the lower part of the ion-exchange column is placed a pad of glass wool, then fill the column with a layer height of between 300 and 320 mm, while carefully monitored to ensure that air bubbles did not stay between the grains of resin. After filling the column through the resin flow 100 cmof 2 mol/DM
hydrochloric acid solution.
Before analysis, the height of 2 mol/DMhydrochloric acid solution over the resin must be 10−20 mm.
At the end of the chromatographic separation resin is regenerated by flushing with water until slightly acidic wash liquid, then the transmittance of 100 cmof 2 mol/DM
solution of hydrochloric KIS
lots.
3.4. Analysis
3.4.1. For alloys with a mass fraction of tin and lead, more than 0,05%
A sample of alloy weighing 0.25 g were placed in a glass with a capacity of 300 cmand dissolved in 20 cm
of the mixture to dissolve when heated.
After dissolution the solution cautiously evaporated to dryness. To the cooled residue add 10 cmsulphuric acid (1:1) and evaporated until a white smoke of sulfuric acid. The residue is cooled, rinse the walls of the glass with water and evaporated again until a white smoke of sulfuric acid. The residue was cooled, added to 50 cm
of water, boil to dissolve the salt, cooled and allowed to stand for 4 h. the Precipitate of lead sulphate filtered off on a tight filter, washing out the beaker and the precipitate with sulfuric acid (3:100). The precipitate is discarded and the filtrate evaporated to dryness. The cooled residue is dissolved in 50 cm
of 2 mol/DM
hydrochloric acid solution under heating. The solution passed through the column at a rate of 2 cm
/min. Glass column and washed with 200 cm
of 2 mol/DM
hydrochloric acid solution at the same rate until the disappearance of the reaction to ions of copper, Nickel and iron. Zinc eluted with the same speed of 300 cm
of water and collect the eluate in a conical flask with a capacity of 500 cm
. To the solution was added about 0.1 g of a mixture kylinalove orange with sodium chloride; neutralize with ammonia until the appearance of weakly violet colour, add 2.5 cm
of the solution servational sodium, 1 cm
of a solution of sodium fluoride, 10 cm
buffer solution and titrated with a solution of Trilon B colouring in
yellow.
3.4.2. For alloys with a mass fraction of tin and of lead to 0.05%
A portion of the alloy is 0.25 grams placed in a beaker with a capacity of 250 cm, dissolved in 20 cm
of nitric acid (1:1) under heating and the solution was evaporated to dryness. To the residue add 10 cm
of concentrated hydrochloric acid and evaporated to dryness three or four times to remove nitric acid, adding each time 10 cm
of hydrochloric acid. Chilled dry residue is dissolved in 50 cm
of 2 mol/DM
hydrochloric acid when heated, and further analysis is carried out as specified in clause
3.5. Processing of the results
3.5.1. Mass fraction of zinc () in percent is calculated by the formula
where — volume of solution Trilon B, used for titration, cm
;
— mass concentration of the solution Trilon B, g/cm
;
— the weight of the portion,
3.5.2. Discrepancies in the results of three parallel measurements (rate of convergence) and between results of two tests
(a measure of reproducibility) shall not exceed the values of permissible differences given in table.1.
3.5.3. Control of accuracy of analysis results is carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) of copper-Nickel alloys, approved under GOST 8.315, in accordance with GOST 25086.
4. POLAROGRAPHIC METHOD FOR DETERMINING ZINC
4.1. The essence of the method
The method is based on dissolving the sample in nitric acid or mixtures of nitric and hydrofluoric acids (with the mass fraction of silicon of more than 0.5%) or mixtures of bromatological acid and bromine (if the mass fraction of tin and lead, more than 0,05%), the separation of copper electrolytically or chromatography on the anion exchange resin from 2 mol/DMsolution of hydrochloric acid and polarographic determination of zinc in hloridnaja the background in the interval of potentials from minus 1 to minus 1.5 V relative to the saturated calomel electrode.
4.2. Apparatus, reagents and solutions
The ion exchange column 15 mm in diameter, with a height of 200−300 mm.
Polarograph AC complete with all accessories.
Allowed the use of other data handling.
Ion-exchange resin AV-17 GOST 20301.
Allowed to use other resins such as weak anion exchangers (EDE-10P, an-31, Dowex, etc.).
Hydrochloric acid according to GOST 3118 and diluted 1:1, 3:100, and 2 mol/DMsolution.
Nitric acid according to GOST 4461 and diluted 1:1.
Hydrofluoric acid according to GOST 10484.
Sulfuric acid according to GOST 4204, and diluted 1:1 and 3:100.
Bromatologia acid according to GOST 2567.
Bromine according to GOST 454.
Mix to dissolve the freshly prepared: 9 parts bromatological acid is mixed with 1 part of bromine.
Sodium chloride according to GOST 4233, saturated solution.
Potassium hydroxide technical GOST 9285, solution 50 and 100 g/DM.
Silver nitrate according to GOST 1277, a solution of 10 g/DM.
Potassium ferrocyanide according to GOST 4207, a solution of 30 g/DM.
Ammonium chloride according to GOST 3773, 1 mole/DMsolution.
Ammonia water according to GOST 3760, 1 mole/DMsolution.
Hloridnaja buffer solution: prepared by mixing equal volumes of 1 mol/DMsolutions of ammonium chloride and ammonia.
Potassium rodanistye according to GOST 4139, a solution of 10 g/DM.
Nitrogen gas according to GOST 9293.
Mercury GOST 4658 stamps r0, dehydrated.
Zinc GOST 3640 with a mass fraction of zinc not less than 99.9%.
Standard zinc solution: 0.1 g of zinc was dissolved with heating in 30 cmof hydrochloric acid (1:1). The solution is transferred into a measuring flask with volume capacity of 1000 cm
and topped to the mark with water.
1 cmof the solution contains 0.0001 g TS
Inca.
4.3. Preparation for assay
4.3.1. Preparation of ion-exchange columns to work
50 g of the ion exchange resin fractions of 0.25−0.5 mm were placed in a glass with a capacity of 500 cmand pour 400 cm
of sodium chloride solution. The resin is kept in solution for 24 hours at room temperature. Drained and the resin was washed by decantation with hydrochloric acid (3:100) to complete the removal of iron (reaction with romanisti potassium). The resin is successively washed with solution of potassium hydroxide 50 g/cm
, then a solution of potassium hydroxide 100 g/DM
the complete removal of chloride ions (reaction with silver nitrate). The resin was washed with distilled water until a weakly alkaline reaction wash liquid, then treated with three portions of 2 mol/DM
hydrochloric acid solution at 100 cm
each. In the lower part of the ion-exchange column is placed a pad of glass wool, then fill the column with a resin layer height of 200 mm, while carefully monitored to ensure that air bubbles did not stay between the grains of resin. After filling the column, through her missing another 100 cm
of 2 mol/DM
hydrochloric acid solution. The prepared column can be used for 20−25 continuous analyses.
Before analysis, the height of 2 mol/DMhydrochloric acid solution over the resin must be 10−20 mm. In the process of working on the top edge of the resin layer of the liquid should be at least 15−20 mm.
After ion-exchange separation and elution of zinc, the resin is regenerated by flushing with water until slightly acidic (pH 2) reaction of the wash liquid, then the transmittance of 100 cmof 2 mol/DM
solution of hydrochloric KIS
lots.
4.4. Analysis
4.4.1. In the analysis of alloys with a mass fraction of tin, lead and silicon is less than 0.05%
A sample weighing 1 g is placed in a beaker with a capacity of 250 cm, and dissolved in 20 cm
of nitric acid (1:1).
The solution was evaporated to a syrupy state, add 10 cmof hydrochloric acid and evaporated to dryness. Evaporation with 10 cm
of hydrochloric acid is carried out three times, after which the dry residue is dissolved in 50−70 cm
of 2 mol/DM
hydrochloric acid solution and the resulting solution passed through an ion exchange column at a rate of 2 cm
/min.
The column was washed with 150 cmof 2 mol/DM
hydrochloric acid solution at a speed of fluid flow of 2 cm
/min and eluted zinc 250 cm
of water at a rate of 1.5−2 cm
/min, collecting the eluate in a glass with a capacity of 300 cm
.
The solution is evaporated to a volume of 2−3 cm, dilute chloride-ammonia buffer solution, transferred to a volumetric flask with a capacity of 50 cm
and then filled to the mark with the same solution. After 10 min of the solution is transferred into a polarographic cell and polarographic the solution at the required sensitivity of the instrument (the height of the peak or wave of the zinc should be at least 10−15 mm) from minus 1.0 to minus 1.5 V relative to the saturated calomel electrode. Simultaneously with the determination of zinc in the sample perform polarographic determination of samples with the addition of a standard solution. To do this, a sample with a mass of 1 g is added a standard solution of zinc so that the zinc content in the additive was equal to the estimated content of zinc in the sample and then receives, as in the determination of zinc in the analyzed
Oh the sample.
4.4.2. For alloys with a mass fraction of tin, lead, more than 0,05%
A sample weighing 1 g is placed in a beaker with a capacity of 250 cm, cautiously add 20 cm
of the mixture for dissolution and the solution carefully evaporated to dryness. Evaporation with 15 cm
of the mixture to dissolve is repeated three more times. To the residue poured 10 cm
of sulphuric acid (1:1) and evaporated to the appearance of dense white smoke of sulfuric acid. Cool the beaker, add 30 cm
of water, heated to boiling, cooled and filtered off the remaining balance on the tight filter, washing it with a solution of sulfuric acid (3:100). The remainder of the cast. The filtrate was evaporated to dryness, the dry residue is dissolved in 50−70 cm
of 2 mol/DM
hydrochloric acid solution, passed through a column and then do as specified in clause 4.4.1
.
4.4.3. For alloys with a mass fraction of silicon in excess of 0.05%
A sample weighing 1 g is placed in a platinum Cup, dissolved in 20 cmof nitric acid with the addition of 2 cm
hydrofluoric acid, then add 20 cm
of sulphuric acid (1:1) and evaporated to the appearance of dense white smoke of sulfuric acid. Cool Cup, rinse the wall with water and evaporated to dryness. The residue is dissolved in 50−70 cm
of 2 mol/DM
hydrochloric acid solution, passed through a column and then do as specified in clause
4.5. Processing of the results
4.5.1. Mass fraction of zinc () in percent is calculated by the formula
where is the wave height (peak) of zinc, corresponding to the solution of the sample, mm;
wave height (peak) of zinc in a control experiment, mm.
— concentration of standard solution, g/cm
;
— volume Supplement, cm
;
wave height (peak) of zinc, corresponding to the solution of the sample with added standard solution, mm;
— the weight of the portion,
G.
4.5.2. Discrepancies in the results of three parallel measurements (rate of convergence) and the results of the two tests
(index of reproducibility) shall not exceed the permissible differences given in table.2.
Table 2
| Mass fraction of zinc, % |
The allowable divergence, % | ||||||
| From |
0,001 |
to |
0,003 |
incl. |
0,0005 |
0,0007 | |
| SV. |
0,003 |
« |
0,005 |
« |
0,001 |
0,001 | |
| « |
0,005 |
« |
0,01 |
« |
0,002 |
0,003 | |
| « |
0,10 |
« |
0,05 |
« |
0,005 |
0,007 | |
| « |
0,05 |
« |
0,10 |
« |
0,010 |
0,01 | |
| « |
0,10 |
« |
0,25 |
« |
0,015 |
0,02 | |
| « |
0,25 |
« |
0,60 |
« |
0,03 |
0,04 | |
4.5.3. Control of accuracy of analysis results is carried out according to State standard samples (GSO) or industry standard sample (CCA) or by standard samples of the enterprise (SOP) of Nickel, Nickel and copper-Nickel alloys, approved under GOST 8.315, or by a method of additives, or a comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.
5. ATOMIC ABSORPTION METHOD FOR DETERMINING ZINC
5.1.The essence of the method
The method is based on measuring the absorption of light by atoms of zinc, formed by 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 zinc.
Nitric acid according to GOST 4461 and diluted 1:1 and 1:100.
Hydrochloric acid according to GOST 3118 and 2 and 1 mol/DMsolutions.
A mixture of acid: mix one volume of nitric acid with three volumes of hydrochloric acid.
Hydrofluoric acid according to GOST 10484.
Sulfuric acid according to GOST 4204, diluted 1:1.
Zinc GOST 3640.
Standard solutions of zinc
The zinc solution A: 0.1 g of zinc is dissolved by heating in 10 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 1 DM
and topped to the mark with water.
1 cmof the solution contains 0.0001 g of zinc.
A solution of zinc B: 10 cmsolution of zinc And transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark.
1 cmof solution B contains 0,00001 g of zinc.
Copper according to GOST 859*.
______________
* On the territory of the Russian Federation GOST 859−2001. — Note the manufacturer’s database.
Standard copper solution: 10 g of copper was dissolved with heating in 80 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark.
1 cmof the solution contains 0.1 g of copper.
Nickel GOST 849*.
______________
* On the territory of the Russian Federation GOST 849−2008. — Note the manufacturer’s database.
A standard solution of Nickel: 10 g of Nickel is dissolved by heating in 80 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark.
1 cmof the solution contains 0.1 g
Nickel.
5.3. Analysis
A sample of alloy weighing 1 g is taken to determine the mass fraction of zinc of 0.001 to 0.05% by weight of 0.1 g to determine the mass fraction of zinc from 0.05% to 0.6%.
5.3.1. For alloys not containing silicon, tin, and tungsten
A portion of the alloy is dissolved by heating in 10 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark. At the same time spend control experience.
Measure the atomic absorption of zinc in the flame of acetylene-air at a wavelength of 213,9 nm parallel to the calibration solutions.
5.3.2. For alloys with a mass fraction of tin in excess of 0.05%
A portion of the alloy is dissolved by heating in 10 cmof a mixture of acids. The solution was transferred to a volumetric flask with a capacity of 100 cm
and topped to the mark of 1 mol/DM
hydrochloric acid solution. At the same time spend control experience. Measure the atomic absorption of zinc, as specified in clause
5.3.3. For alloys with a mass fraction of silicon in excess of 0.05%
A portion of the alloy placed in a platinum Cup and dissolved by heating in 10 cmof nitric acid (1:1) and 2 cm
fluoride-hydrogen acid. Then add 10 cm
sulphuric acid (1:1) and evaporated until a white smoke of sulfuric acid. Cup cooled and the residue is dissolved in 50 cm
of 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. At the same time spend control experience. Measure the atomic absorption of zinc, as specified in clause
5.3.4. For alloys containing tungsten
A portion of the alloy is dissolved by heating in 10 cmof nitric acid (1:1), then add 30 cm
of hot water and the precipitate tungsten acid is filtered off on a tight filter and washed with hot nitric acid (1:100). The filtrate is transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark. At the same time spend control experience. Measure the atomic absorption, as described in Chapter
5.3.5. Construction of calibration curve
In eight of the nine volumetric flasks with a capacity of 100 cmis placed 1,0; 5,0 cm
standard solution B; 1,0; 2,0; 3,0; 4,0; 5,0 and 6.0 cm
to the standard solution And zinc, which corresponds to 0,01; 0,05; 0,1; 0,2; 0,3; 0,4; 0,5 and 0.6 mg of zinc. All flasks is poured 10 cm
of 2 mol/DM
hydrochloric acid solution. For the mass concentration of zinc is less than 0.05% is added to 10 cm
of a solution of copper (if copper is the basis of alloy) or Nickel (when Nickel is the substrate) and top up with water to the mark. Measure the atomic absorption of zinc, as specified in clause
5.4. Processing of the results
5.4.1. Mass fraction of zinc () in percent is calculated by the formula
where is the concentration of zinc in the sample solution alloy, was found in the calibration schedule, g/cm
;
the concentration of zinc in solution in the reference experiment, was found in the calibration schedule, g/cm
;
— the volume of the sample solution, cm
;
— weight of sample, g
.
5.4.2. Discrepancies in the results of three parallel measurements (rate of convergence) and the results of the two tests
(index of reproducibility) shall not exceed the values of permissible differences given in table.2.
5.4.3. Control of accuracy of analysis results is carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) of Nickel, Nickel and copper-Nickel alloys, approved under GOST 8.315, or by a method of additives, or a comparison of the results obtained of the polarographic method, in accordance with GOST 25086.
