GOST 1953.6-79
GOST 1953.6−79 Bronze tin. Methods for determination of zinc (with Amendments No. 1, 2)
GOST 1953.6−79
Group B59
INTERSTATE STANDARD
BRONZE TIN
Methods for determination of zinc
Tin bronze.
Methods for the determination of zinc
AXTU 1709
Date of introduction 1981−01−01
INFORMATION DATA
1. DEVELOPED AND implemented* the Ministry of nonferrous metallurgy of the USSR
________________
* The text of the document matches the original. — Note the manufacturer’s database.
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. The standard fully complies ST SEV 1529−79
4. REPLACE GOST 1953.6−74
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document, to which this links |
The number of the paragraph, subparagraph |
| GOST 8.315−97 |
2.4.4, 3.5.4, 4.4.4, 5.5.4, 6.4.4, 7.4.4, 8.4.4 |
| GOST 61−75 |
5.2 |
| GOST 199−78 |
4.2 |
| GOST 454−76 |
5.2 |
| GOST 613−79 |
Chapeau |
| GOST 614−97 |
Chapeau |
| GOST 701−89 |
2.2 |
| GOST 859−2001 |
3.2 |
| GOST 860−75 |
4.2 |
| GOST 1277−75 |
3.1 |
| GOST 1381−73 |
4.2 |
| GOST 1953.1−79 |
1.1, 8.1 |
| GOST 1953.2−79 |
8.1 |
| GOST 1953.3−79 |
8.1 |
| GOST 1953.6−79 |
8.1 |
| GOST 2062−77 |
2.2 |
| GOST 2567−89 |
3.1, 5.2 |
| GOST 3118−77 |
3.2, 4.2, 5.2, 6.2, 7.2 |
| GOST 3640−94 |
2.2, 3.2, 4.2, 5.2, 6.2, 7.2, 8.2 |
| GOST 3760−79 |
4.2, 5.2, 6.2, 7.2 |
| GOST 3773−72 |
7.2, 8.2 |
| GOST 4109−79 |
2.2 |
| GOST 4139−75 |
3.2, 5.2 |
| GOST 4166−76 |
3.1 |
| GOST 4204−77 |
5.2, 7.2, 8.2 |
| GOST 4220−75 |
7.2 |
| GOST 4233−77 |
3.2, 4.2, 5.2, 7.2, 8.2 |
| GOST 4328−77 |
5.2 |
| GOST 4461−77 |
3.2, 4.2, 6.1, 7.2, 8.2 |
| GOST 4463−76 |
4.2 |
| GOST 4518−75 |
4.2 |
| GOST 4658−73 |
2.2, 3.2 |
| GOST 5828−77 |
7.2 |
| GOST 6344−73 |
4.2, 8.2 |
| GOST 6552−80 |
2.2, 3.2 |
| GOST 6563−75 |
2.2, 8.2 |
| GOST 8864−71 |
8.2 |
| GOST 9285−78 |
3.1 |
| GOST 9293−74 |
2.2, 3.2 |
| GOST 9546−75 |
4.2 |
| GOST 10652−73 |
4.2, 5.2, 7.2, 8.2 |
| GOST 11293−89 |
3.2 |
| GOST 14261−77 |
3.2 |
| GOST 19522−74 |
4.2 |
| GOST 20301−74 |
3.1, 5.2 |
| GOST 25086−87 |
1.1, 2.4.4, 3.5.4, 4.4.4, 5.5.4, 6.4.4, 7.4.4, 8.4.4 |
6. Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)
7. EDITION with Amendments No. 1, 2 approved in February 1983, August 1990 (IUS 6−83,11−90)
This standard specifies the polarographic methods for the determination of zinc (from 0.001% to 0.04% and from 0.01% to 4%), titrimetric methods for the determination of zinc (from 1.5% to 17% and from 1.5% to 30%) and atomic absorption method for the determination of zinc (from 0.1% to 10%) in tin bronze according to GOST 5017, GOST GOST 613 and 614.
The standard fully complies ST SEV 1529−79.
(Changed edition, Rev. N 1, 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 with the Supplement according to claim 1.1 GOST 1953.1.
(Changed edition, Rev. N 1, 2).
2. POLAROGRAPHIC METHOD for the DETERMINATION of ZINC (from 0.001% to 0.03%)
2.1. The essence of the method
The method is based on a consistent preliminary separation of tin in the form of volatile tetrabromide and the main mass of copper by electrolysis with subsequent determination of the zinc on the background of phosphoric acid by the method of alternating-current polarography.
2.2. Apparatus, reagents and solutions
Polarograph alternating current and the cell with an external electrode (saturated calomel electrode) and mercury-drip cathode.
Mercury brands r0 according to GOST 4658, drained.
Nitrogen gas according to GOST 9293.
Bromatologia acid according to GOST 2062.
Nitric acid according to GOST 701 and diluted 1:1.
Bromine according to GOST 4109.
Mix to dissolve, freshly prepared; prepared as follows: nine volumes bromatological acid is mixed with one volume of bromine.
Installation of electrolysis.
The electrodes are platinum according to GOST 6563.
The acid chloride.
Orthophosphoric acid according to GOST 6552, 1 mole/DMsolution.
Zinc brand C1, C0 or Ц00, GOST 3640, solutions.
Standard solutions of zinc. Solution A, prepared as follows: 0.1 g of zinc is dissolved in 10 cmof nitric acid, diluted 1:1, boil the solution to remove the oxides of nitrogen, 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 zinc.
Solution B is prepared as follows: 10 cmof the solution And transferred to a volumetric flask with a capacity of 100 cm
, add 1 cm
of nitric acid, diluted 1:1, made up to the mark with water and mix.
1 cmof a solution contains 0.0001 g of zinc.
2.3. Analysis
Weighed bronze (see table.1) is placed in a beaker with a capacity of 250 cm, covered with a glass watch glass and carefully dissolved by heating at 40 cm
of the mixture for dissolution. In case of incomplete dissolution of the sample into the solution drop by drop carefully add bromine. Upon completion of the dissolution solution was poured to 20 cm
of perchloric acid and evaporated the solution at a moderate heat to release thick white smoke and lightening solution. The solution was cooled, rinse walls of beaker and watch glass with water and repeat the evaporation until the appearance of dense white smoke of perchloric acid.
Table 1
| Mass fraction zinc, % |
Weight charge, g |
Polarographically |
| From 0.001 to 0.005 |
2 |
25 |
| «Of 0.005» to 0.015 |
1 |
10 |
| «0,015» 0,03 |
0,5 |
10 |
Dilute the solution with water to 100−150 cm, add 7 cm
of sulphuric acid, diluted 1:4, and 3 cm
of concentrated nitric acid. The solution is electrolyzed at a current of 2,5−3 A for 1.5 h and Then added to the electrolysis 25−30 cm
of water and, after 15 min re-covered by the solution cathode surface is not appearing precipitate of copper, electrolysis is complete. Rinse the electrodes with water without interrupting the current. The electrolyte after electrolysis was evaporated to wet salts, the salt is dissolved in 20 cm
1 mol/DM
solution of phosphoric acid, the resulting solution was transferred into a measuring flask with a capacity of 50 cm
, made up to the mark solution of 1 mole/DM
solution of phosphoric acid and stirred. Aliquot part of the solution (see table.1) is transferred into a polarographic cell, is passed through a solution of nitrogen for 5−6 min and polarography in the range of -0.8 to -1.3 V, recording the peak recovery of zinc at -1,05 V.
The zinc content of the bronze was determined by standard addition. To do this, 0,1−0,5 cmstandard solution B zinc is introduced into the polarographic cell, stirred the solution with nitrogen for 1 min and then do the same as in the polarographic determination of zinc in the analyzed solution. The volume of standard addition are selected so that the magnitude of the peak after the addition of zinc increased in 2−3 times in comparison with the peak of zinc in polarography the analyzed solution.
Simultaneously with the determination of zinc in bronze spend control experience with all reagents as described above.
2.2, 2.3. (Changed edition, Rev. N 2).
2.4. Processing of the results
2.4.1. Mass fraction of zinc () in percent is calculated by the formula
where is the height of the peak of the zinc test solution, mm;
— the height of the peak of the zinc after the introduction of standard additives, mm;
- the height of the peak of zinc in a control experiment, mm.
— the concentration of a standard solution of zinc, g/cm
;
- the volume of standard addition, cm
;
- the weight of bronze, taken on polarography,
2.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for
3) specified in table.2.
Table 2
| Mass fraction of zinc, % |
|
|
| From 0.001 to 0.0025 incl. |
0,0004 |
About 0.0006 |
| SV. 0,0025 «0,0050 « |
About 0.0006 |
0,0008 |
| «0,005» 0,010 « |
0,001 |
0,001 |
| «Of 0.010» to 0.025 « |
0,002 |
0,003 |
| «0,025» 0,050 « |
0,004 |
0,006 |
| «0,05» 0,10 « |
0,008 |
0,01 |
| «To 0.10» to 0.25 « |
0,015 |
0,02 |
| «0,25» 0,50 « |
0,03 |
0,04 |
| «0,5» 1,5 « |
0,04 |
0,06 |
| «1,5» 3,0 « |
0,07 |
0,10 |
| «3,0» 5,0 « |
0,10 |
0,14 |
| «5,0» 10,0 « |
0,12 |
0,2 |
| «10,0» 20,0 « |
0,20 |
0,3 |
| «20,0» 30,0 « |
0,30 |
0,4 |
(Changed edition, Rev. N 2).
2.4.3. 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 (-an indicator of reproducibility) shall not exceed the values specified in table.2.
2.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or by a method of additives in accordance with GOST 25086.
2.4.3,
3. POLAROGRAPHIC METHOD for the DETERMINATION of ZINC (from 1.0% to 4%)
3.1.The essence of the method
The method is based on dissolution of bronze in the mix bromatological acid and bromine, chromatographic separation of the zinc on the resin, the elution of zinc with water and polarographic determination of zinc in floridaamerican the background in the interval of potentials from minus 1 to minus 1.5 V relative to the saturated calomel electrode.
3.2. Apparatus, reagents and solutions
The ion exchange column 15 mm in diameter, with a height of 250−300 mm.
Polarograph AC complete with all accessories.
Allowed the use of other data handling.
Ion-exchange resin brand AV-17 GOST 20301.
Allowed to use other resins such as weak anion exchangers (EDZ-10P, an-31, Dowex, etc.).
Hydrochloric acid according to GOST 14261, 2 mol/DMsolution.
Gelatin GOST 11293.
Sulfuric acid according to GOST 4204, and diluted 1:1 and 3:100.
Bromatologia acid according to GOST 2567.
Bromine according to GOST 4109.
The mixture for dissolving freshly prepared; prepared as follows: 9 parts bromatological acid mixed with one part of bromine.
Sodium chloride according to GOST 4233, saturated solution.
Sodium sanitarily according to GOST 4166.
The hydroxide of potassium (potassium hydroxide) according to GOST 9285, solution 50 and 100 g/DM.
Silver nitrate according to GOST 1277, a solution of 10 g/DM.
Ammonium chloride according to GOST 3773.
Ammonia water according to GOST 3760.
Ammonia buffer solution was prepared in the following way: 53 g of ammonium chloride and 25 g semitecolo sodium dissolved in 500 cmof water, and 0.2 gelatin is dissolved in 50 cm
of hot water. After cooling, combine the two solutions, add 75 cm
of ammonia and add water to 1 DM
.
Potassium rodanistye according to GOST 4139, a solution of 10 g/DM.
Nitrogen gas according to GOST 9293.
Mercury GOST 4658, marks 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 diluted 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 of zinc.
3.3. Preparation of ion-exchange columns to work
50 g of ion exchange resins fraction 0.25−0.5 mm were placed in a glass with a capacity of 500 cm, pour 400 cm
of sodium chloride solution. The resin is kept for 24 hours at room temperature. The solution is decanted and the resin was washed by decantation with hydrochloric acid, dilute 3:100, to the complete removal of iron (reaction with romanisti potassium).
Then the resin is successively washed with solution of potassium hydroxide 50 g/DM, water and then a solution of potassium hydroxide 100 g/DM
the complete removal of chloride ions (reaction with silver nitrate), distilled water to slightly 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 the resin flow 100 cmof 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 tar regeniriruyut by washing with water until slightly acidic (pH2) of the reaction of the wash liquid, then the transmittance of 100 cmof 2 mol/DM
hydrochloric acid solution.
3.4. Analysis
The sample of bronze with a weight of 1 g was 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 repeat 3 more times. To the residue poured 10 cm
of sulphuric acid diluted 1:1, and evaporated until 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 precipitate of lead sulfate on thick filter, washing it with a solution of sulfuric acid, dilute 3:100.
The filtrate was evaporated to dryness, the dry residue is dissolved in 50−70 cmof 2 mol/DM
hydrochloric acid solution and pass the solution 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 weight 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 a sample.
When working with polarography DC solution add 1−2 crystal semitecolo sodium.
3.5. Processing of the results
3.5.1. 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, corresponding to the solution of the sample with the additive standard solution, mm;
— the mass of the zinc in the additive standard solution, g;
- mass of analyzed sample, g.
3.1 to 3.5.1 (Revised edition, Edit. N 1).
3.5.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for
3) specified in table.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 (-an indicator of reproducibility) shall not exceed the values specified in table.2.
3.5.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or a comparison of the results obtained by AAS or titrimetric methods, in accordance with GOST 25086.
3.5.3,
4. TITRIMETRIC CHELATOMETRIC METHOD for the DETERMINATION of ZINC IN a BRONZE THAT does NOT CONTAIN NICKEL AND LEAD (from 1.5% to 17%)
4.1.The essence of the method
The method is based on complexometric titration of zinc in the presence kylinalove orange as indicator after masking of copper with sodium thiosulphate.
4.2. Reagents and solutions
Nitric acid according to GOST 4461, H. h
Hydrochloric acid according to GOST 3118, H. h and diluted 1:1.
The mixture of acids to dissolve fresh: one volume of nitric acid mixed with three volumes of hydrochloric acid.
Ammonia water according to GOST 3760.
Ammonium fluoride (fluoride) according to GOST 4518, solution 200 g/DM.
Ammonium fluoride acidic (before) according to GOST 9546.
Chernovetskiy sodium (sodium thiosulfate), a solution of 200 g/DM.
Sodium acetate according to GOST 199, a solution of 200 g/DM.
Selenology orange.
Sodium chloride according to GOST 4233.
Indicator mixture: selenology orange triturated with sodium chloride in a ratio of 1:100.
Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid, 2-water (Trilon B) according to GOST 10652, solutions of 0.025 and 0.01 mol/DM, prepare fiksanala or as follows: 9,305 g or 3,7224 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.
Zinc GOST 3640, brand TSO or zoo.
Standard solution of zinc, 1 g of zinc metal is dissolved in 25 cmof hydrochloric acid (1:1) solution was evaporated to dryness, the dry residue dissolved in 10 cm
of hydrochloric acid (1:1), transferred to a volumetric flask with a capacity of 1 DM
and topped to the mark with water.
1 cmof the solution contains 0.001 g of zinc.
Determination of the mass concentration of the solution Trilon B.
25 cmof a solution of zinc is placed in a conical flask with a capacity of 500 cm
and neutralized with ammonia solution till the formation of zinc hydroxide. Then add 20 cm
of a solution of ammonium fluoride, mix, add dry salt byflorida ammonium to dissolve the residue, 20 cm
of sodium thiosulfate, 20 cm
sodium acetate, dilute with water to 200 cm
, add the mixture of indicator and titrated with a solution of Trilon B to change red color to light yellow.
The mass concentration of the solution Trilon B (), expressed in grams of zinc on 1 cm
of a solution, calculated by the formula
where - the mass of zinc, taken for titration, g;
- volume of solution Trilon B, spent on titration, sm
.
4.3. Analysis
The weight of bronze (PL.3) is placed in a beaker with a capacity of 200−300 cm, add 20 cm
of a mixture of acids and dissolved by heating.
Table 3
| Mass fraction of zinc, % |
The mass of charge, g |
Aliquota part of the solution, see |
A charge corresponding to aliquote part of the solution, g |
The concentration of Trilon B solution, mol/DM |
| From 1.5 to 10 incl. |
0,2 |
50 |
0,1 |
0,01 |
| SV. 10 to 17 « |
0,2 |
25 |
0,05 |
0,025 |
After dissolution, the sample solution is transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.
Aliquot part of the solution (table.3) is placed in a conical flask with a capacity of 500 cmand with stirring add dropwise ammonia solution prior to the precipitation of copper hydroxide. Then add 20 cm
of a solution of ammonium fluoride, mix and add dry salt byflorida of ammonia to dissolve the precipitate. To the solution was added 20 cm
of sodium thiosulfate, 20 cm
of a solution of sodium acetate (to pH 5,6−6,0), dilute with water to 200 cm
, add the mixture of indicator and titrated with a solution of Trilon B (tab.3) changes to red-purple color in light yellow.
4.4. Processing of the results
4.4.1. 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 for zinc, g/cm
;
- the weight of the portion corresponding to aliquote part of the solution,
4.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for
3) specified in table.2.
4.4.3. 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 (-an indicator of reproducibility) shall not exceed the values specified in table.2.
4.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or a comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.
Sec. 4. (Changed edition, Rev. N 2).
5. TITRIMETRIC METHOD for the DETERMINATION of ZINC WITH the separation of the ZINC ON the ANION exchange resin (from 1.5% to 30%)
5.1. The essence of the method
The method is based on complexometric titration of zinc after its separation on strong-base anion exchanger.
5.2. 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 mm* diameter of 12−15 mm).
_________________
* The text of the document matches the original. — Note the manufacturer’s database.
Ion-exchange resin an-31 according to GOST 20301.
Hydrochloric acid according to GOST 3118 and diluted 1:1, 1:20 and 2 mol/DMsolution.
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.
The mixture for dissolving freshly prepared; prepared as follows: 9 parts bromatological acid mixed with one part of bromine.
Sodium hydroxide (caustic soda) according to GOST 4328, solution 50 g/land 100 g/DM
.
Ammonia water according to GOST 3760 and diluted 1:5.
Sodium fluoride, a solution of 100 g/DM.
Sodium Chernovetskiy, a solution of 200 g/DM.
Buffer solution pH-5,7 prepared as follows: 96 cmacetic acid and 115 cm
of ammonia, dilute with water to 1000 cm
.
Selenology orange.
The mixture kylinalove orange with sodium chloride in a ratio of 1:100.
Sodium chloride according to GOST 4233 and a saturated solution.
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; prepared as follows: 1 g of zinc is dissolved in 25 cmof hydrochloric acid diluted 1:1, the solution was evaporated to dryness, the dry residue dissolved in 100 cm
of hydrochloric acid diluted 1:1, transferred into 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/DMsolution.
The installation of the mass concentration of the solution Trilon B:
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.
The mass concentration of the solution Trilon B (), expressed in grams of zinc on 1 cm
of a solution, calculated by the formula
where - the mass of zinc, taken for titration, g;
- volume of solution Trilon B, spent on titration, sm
.
(Changed edition, Rev. N 2).
5.3. Preparation of chromatographic columns to work
50 g of ion-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, dilute 3:100, to the complete 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 chloride ions (reaction with silver nitrate), the resin was 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 of resin height mm 300−320 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 the hydrochloric acid solution over the resin must be 10−20 mm.
After chromatographic separation resin regeniriruyut by washing with water until slightly acidic wash liquid, and then by passing 100 cmof 2 mol/DM
hydrochloric acid solution.
5.4. Analysis
Weighed bronze (see table.4) is placed in a beaker with a capacity of 300 cmand 20 cm dissolved
mixture to dissolve when heated. After dissolution the solution cautiously evaporated to dryness. Evaporation with 15 cm
of the mixture to dissolve, repeat 3−4 times. To the cooled residue add 10 cm
sulphuric acid diluted 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.
Table 4
| Mass fraction of lead, % |
The mass of charge, g |
| From 1.5 to 5.0 |
1 |
| SV. 5,0 «10,0 |
0,5 |
| «10,0» 30,0 |
0,25 |
The precipitate of lead sulphate filtered off on a tight filter, washing out the beaker and precipitate the sulfuric acid, dilute 3:100. The precipitate is discarded and the filtrate evaporated to dryness.
Chilled dry residue is dissolved in 50−70 cmof 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, flowing the 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 450 cmof 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, is neutralized with ammonia until the appearance of weakly violet colour, add 2.5 cm
of the solution, chernovetskogo 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.
(Changed edition, Rev. N 2).
5.5. Processing of the results
5.5.1. Mass fraction of zinc (a) percentage 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,
5.5.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for
3) specified in table.2.
5.5.1,
5.5.3. 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 (-an indicator of reproducibility) shall not exceed the values specified in table.2.
5.5.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or a comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.
5.5.3,
6. ATOMIC ABSORPTION METHOD (from 0.1% to 10%)
6.1. 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.
6.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with a radiation source for zinc.
Nitric acid according to GOST 4461 and diluted 1:1.
Hydrochloric acid according to GOST 3118 and diluted 1:1, 2 mol/land 1 mol/DM
solutions.
The mixture of acids to dissolve, is prepared as follows: the amount of nitric acid mixed with three volumes of hydrochloric acid.
Zinc GOST 3640 with a mass fraction of zinc not less than 99.9%.
Standard solutions of zinc.
Solution A, prepared as follows: 0.5 g of zinc is 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 zinc.
Solution B is prepared as follows: 20 cmsolution And transferred to 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 zinc.
Solution; prepared as follows: 10 cmof a solution transferred to 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 the solution contains 0,00001 g of zinc.
6.3. Analysis
A portion of the bronze mass (see table.5) 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 an appropriate volumetric flask (see table 5) rinse walls of beaker 1 mol/DM
solution of hydrochloric acid and topped up to the mark with the same acid.
Table 5
| Mass fraction of zinc, % |
The mass of charge, g |
The volume of the solution |
The volume aliquote part of the solution, cm |
The volume |
The volume of solution after dilution |
| From 0.01 to 0.05 incl. |
1 |
100 |
The entire solution |
- |
- |
| SV. Of 0.05 «to 0.5 « |
1 |
100 |
10 |
10 |
100 |
| «Of 0.5» to 4.0 « |
0,5 |
250 |
5 |
10 |
100 |
| «4,0» 10 « |
0,5 |
250 |
5 |
25 |
250 |
Aliquot part of the solution transferred to an appropriate volumetric flask (see table 5) and made up to the marks 1 mol/DMhydrochloric acid solution.
Measure the atomic absorption of zinc in the flame of acetylene-air at a wavelength of 213,8 nm parallel to the calibration solutions.
(Changed edition, Rev. N 2).
6.3.1. Construction of calibration curve
Ten of the eleven volumetric flasks with a capacity of 100 cmis placed 2,5; 5,0; 10 cm
standard solution Into; 1,5; 2,0; 2,5; 3,0; 4,0; 5,0 and 6.0 cm
to the standard solution of zinc. To all flasks add 10 cm
of 2 mol/DM
hydrochloric acid solution and then filled to the mark with water.
Measure the atomic absorption of zinc, as specified in clause 6.3. According to the obtained results build a calibration curve.
6.4. Processing of the results
6.4.1. Mass fraction of zinc () in percent is calculated by the formula
where — concentration of zinc 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. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for
3) specified in table.2.
(Changed edition, Rev. N 2).
6.4.3. 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 (-an indicator of reproducibility) shall not exceed the values specified in table.2.
6.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or a comparison of the results obtained by the titrimetric method in accordance with GOST 25086.
6.4.3,
7. TITRIMETRIC CHELATOMETRIC METHOD for the DETERMINATION of ZINC IN BRONZES IN the PRESENCE of NICKEL AND LEAD (from 1.5% to 17%)
7.1. The essence of the method
The method is based on complexometric titration of zinc in the presence of Chromogen black as indicator after the separation of copper with sodium thiosulphate and the binding of iron and Nickel in the complex of ammonium with a solution dimethylglyoxime.
7.2. Reagents and solutions
Nitric acid according to GOST 4461.
Hydrochloric acid according to GOST 3118 and diluted 1:1.
The mixture of acids to dissolve fresh: one volume of nitric acid mixed with three volumes of hydrochloric acid.
Sulfuric acid according to GOST 4204.
Ammonia water according to GOST 3760.
Ammonium chloride according to GOST 3773, a solution of 250 g/DM.
Chernovetskiy sodium (thiosulfate), a solution of 200 g/DM.
Sodium chloride according to GOST 4233.
Potassium dichromate according to GOST 4220, a solution of 100 g/DM.
Dimethylglyoxime according to GOST 5828, a solution of 10 g/DMof ammonia.
Methyl red, solution 1 g/DM.
The Chromogen black.
Indicator mixture: Chromogen black well triturated with the sodium chloride in the ratio of 1:100.
Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid, 2-water (Trilon B) according to GOST 10652, solutions of 0.025 and 0.01 mol/DM.
Zinc GOST 3640, brand TSO or zoo.
Standard zinc solution: 0.1 g of zinc metal are dissolved in 15 cmof hydrochloric acid (1:1) solution was evaporated to dryness, the dry residue dissolved in 10 cm
of hydrochloric acid (1:1), transferred to a volumetric flask with a capacity of 100 mm
and then filled to the mark with water.
1 cmof the solution contains 0.001 g of zinc.
Determination of the mass concentration of the solution Trilon B
25 cmstandard solution of zinc is placed in a conical flask with a capacity of 500 cm
, adding 25 cm
of a solution of ammonium chloride, 2−3 drops methyl red and the solution is neutralized with ammonia solution dimethylglyoxime to the transition of color from red to yellow and even an excess of 5 cm
. Then add 5−6 drops of a solution of potassium dichromate, the indicator mixture and the solution was titrated with Trilon B before the transition red-violet color in green.
The mass concentration of the solution Trilon B (), expressed in grams of zinc on 1 cm
of a solution, calculated by the formula
where - the mass of zinc, taken for titration, g;
- volume of solution Trilon B, spent on titration, sm
.
7.3. Analysis
The weight of bronze weighing 0.2 g was placed in a beaker with a capacity of 250 cm, adding 10 cm
of the mixture of acids and dissolved by heating. The cooled solution was added 4 cm
of sulphuric acid and evaporate to release white smoke of sulfuric acid. The residue is cooled, rinse the walls of the glass with water and again evaporated to release white smoke of sulfuric acid. To the cooled residue add 100−150 cm
of water and heated to dissolve the salts. The cooled solution is transferred to a volumetric flask with a capacity of 250 cm
, made up to the mark with water and mix. The flask is allowed to stand for settling of the precipitate of lead sulfate. You can filter the precipitate through dense dry filter into a dry flask. Then select aliquot part of the solution (see table.3), placed in a beaker with a capacity of 250 cm
, and topped up with water to 100 cm
. The solution was added sodium thiosulfate until the appearance of white turbidity, boil the solution to coagulate the precipitate of copper sulfide and produce a clear solution above the sediment. The solution was filtered through the filter into the conical flask with a capacity of 500 cm
, the filter cake washed several times with hot water and discarded.
To the filtrate add 25 cmof a solution of ammonium chloride to keep the zinc in solution of 2−3 drops of methyl red and the solution is neutralized with ammonia solution dimethylglyoxime to the transition of color from red to yellow and even an excess of 5 cm
. To the solution add 5−6 drops of a solution of potassium dichromate, the indicator and the mixture titrated with Trilon B (see table.3), the transition red-violet color in green.
7.4. Processing of the results
7.4.1. 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 for zinc, g/cm
;
- the weight of the portion corresponding to aliquote part of the solution,
7.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for
3) specified in table.2.
7.4.3. 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 (-an indicator of reproducibility) shall not exceed the values specified in table.2.
7.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or a comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.
Sec. 7. (Added, Rev. N 2).
8. TITRIMETRIC CHELATOMETRIC METHOD FOR THE DETERMINATION OF ZINC (DETERMINATION OF TIN, LEAD, COPPER AND ZINC FROM ONE SAMPLE)
8.1. The essence of the method
The method is based on sequential separation of zinc from tin, lead and copper according to GOST 1953.1 from one sample and determining the titrimetric method.
Tin is determined according to GOST 1953.6.
Lead is determined according to GOST 1953.2.
Copper is determined according to GOST 1953.1.
From the solution freed from tin, lead and copper to determine the zinc chelatometric titration in the presence eriochrome black T as indicator.
8.2. Apparatus, reagents and solutions
Installation of electrolysis.
The electrodes are platinum according to GOST 6563.
Nitric acid according to GOST 4461, diluted 1:1.
Sulfuric acid according to GOST 4204, diluted 1:1, 1:4 and 1:100.
Ammonia water according to GOST 3760.
Ammonia chloride according to GOST 3773.
Sodium chloride according to GOST 4233.
Buffer solution: 20 g of ammonium chloride dissolved in water, add 100 cmof ammonia solution and dilute with water to 1 DM
.
Diethyldithiocarbamate sodium GOST 8864, a solution of 30 g/DM.
Thiourea according to GOST 6344, solution 100 g/DM.
Eriochrome black T.
Indicator mixture: eriochrome black T is well triturated with the sodium chloride in the ratio of 1:100.
Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid, 2-water (Trilon B) according to GOST 10652, solution 0,025 mol/DM(see preparation p.4.2).
Zinc GOST 3640, brand TSO or zoo.
Standard zinc solution: 0.1 g of zinc is dissolved in 10 cmof nitric acid (1:1), the solution transferred to a volumetric flask with a capacity of 100 mm
and up to the mark and top up with water.
1 cmof the solution contains 0.001 g of zinc.
Determination of the mass concentration of the solution Trilon B
10 cmsolution of zinc is placed in a conical flask with a capacity of 500 cm
, add 100 cm
of water and neutralized with ammonia solution before staining litmus paper blue. Then add 3 drops of a solution of sodium diethyldithiocarbamate to bind traces of copper (in the presence of copper the solution will take a brownish-yellow color), 10 cm
buffer solution, indicator of the mixture of ~0.2 g and the solution is titrated with a solution of Trilon B to change the cherry color of the solution in dark green.
The mass concentration of the solution Trilon B () expressed in grams of zinc on 1 cm
of a solution, calculated by the formula
where 0,01 is the mass of zinc, taken for titration, g;- volume of solution Trilon B, spent on titration, sm
.
8.3. Analysis
The solution freed from tin, lead and copper (see p. 8.1), transferred to a conical flask with a capacity of 500 cmand neutralized with ammonia solution before staining litmus paper blue. Then add 3 drops of a solution of sodium diethyldithiocarbamate for binding the residual copper (in the presence of copper the solution will take a brownish-yellow color), 10 cm
buffer solution, indicator of the mixture of ~0.2 g and the solution is titrated with a solution of Trilon B to change the cherry color of the solution in dark green.
Note. A solution of sodium diethyldithiocarbamate can be replaced with a solution of thiourea. In this case, the solution freed from tin, lead and copper, first you add 2 drops of thiourea solution, and then conducting the neutralization of the solution. After neutralizing, add buffer solution, indicator mixture and the solution was titrated with Trilon B to change the color of the solution blue.
The solution for titration must be cold.
8.4. Processing of the results
8.4.1. 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,
8.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (- rate of convergence for
3) specified in table.2.
8.4.3. 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 specified in table.2.
8.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or a comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.
Sec. 8. (Added, Rev. N 2).
