GOST 21877.3-76

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  ГОСТ 21877.3-76

GOST 21877.3−76 Babbit tin and lead. Methods for determination of copper and lead (with Amendments No. 1, 2)

GOST 21877.3−76

Group B59

STATE STANDARD OF THE USSR

BABBIT TIN AND LEAD

Methods for determination of copper and lead

Tin and lead babbits. Methods for the determination of copper and lead*

AXTU 1709**
________________
* The name of the standard. Changed the wording, Rev. N 2.
** Added, Rev. N 2.

Valid from 01.01.78
to 01.01.83*
_______________________________
* Expiration removed
according to the Protocol of the Intergovernmental Council
for standardization, Metrology
and certification (I & C N 2, 1993). -
Note the manufacturer’s database.

DEVELOPED by the Central research Institute for tin industry (Tsniiolovo)

Director V. A. Arsenico

Supervisor S. V. Meshkov

Executor G. V. Ivanova

INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

Zam. Minister N.N. Chepelenko

The draft all-Union scientific research Institute of standardization (VNIIS)

Director A. V. Gichev

APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from may 24, 1976 N 1264

REPLACE GOST 1380.3−70

MADE: the Change in N 1, approved and put into effect by the Decree of the USSR State Committee for standards from 14.02.83 N 804 01.07.83, Change No. 2, approved and put into effect by the Decree of the USSR State Committee for standards from 25.06.87 N 2463 with 01.03.88

Change N 1, 2 made by the manufacturer of the database in the text N 6 ICS 1983 ICS N 10 1987


This standard applies to tin and lead babbits and sets the weighting method for the electrolytic determination of copper content (when the content of copper is from 0.1 to 7%) and lead (with lead content of 0.1 to 0.5%) and periadolescence method for the determination of the copper content and atomic absorption method for the determination of copper content (when the copper content from 0.1% to 7%).

(Changed edition, Rev. N 1, 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 21877.0−76.

2. ELECTROLYTIC METHOD FOR THE DETERMINATION OF THE CONTENT OF COPPER AND LEAD

2.1. The essence of the method

The sample is dissolved in a mixture of acids. Tin and antimony is distilled off in the form of bromide. Lead in the content of his above 1% is separated in the form of sulfate salts. In nitrate solution copper and lead is isolated by electrolysis.

2.2. Apparatus, reagents and solutions

The cylindrical platinum mesh electrodes according to GOST 6563−75.

The electrolyzer with a stirrer, designed for a DC current of 3 A.

Hydrochloric acid by the GOST 3118−77.

Nitric acid GOST 4461−77 diluted 1:1.

Sulfuric acid GOST 4204−77, diluted 1:1 and 2:98.

Bromatologia acid according to GOST 2062−77.

Bromine according to GOST 4109−79.

The mixture of acids to dissolve; prepared as follows: 45 cm. hydrochloric acid are mixed with 45 cmbromatological acid and poured 10 cmof bromine.

Ethyl alcohol according to GOST 5962−67*.
______________
* On the territory of the Russian Federation GOST R 51652−2000. — Note the manufacturer’s database.

Urea according to GOST 5691−77.

Ammonium nitrate according to GOST 22867−77.

(Changed edition, Rev. N 1).

2.3. Analysis

2.3.1. A portion of the Babbitt weight of 1.0−2.0 g were placed in a glass with a capacity of 250 cm, is dissolved in 30 cmof the mixture of acids to dissolve and evaporate with a moderate heat to dryness. Then to the dry residue poured another 10 cmof the mixture and evaporated again to dryness. The Stripping of tin and antimony again, rinsing with a mixture of acids the walls of the glass. To the dry residue add 20 cmof nitric acid, diluted 1:1, and boil to remove the bromine. Further, depending on the content of lead, lead analysis, as mentioned in paragraph 2.3.2 or 2.3.3.

(Changed edition, Rev. N 1).

2.3.2. When the mass fraction of lead to 1% to the solution add 2 g of ammonium nitrate, diluted to about 150 to 180 cmof water and heated to 80−90 °C. the solution is dipped a platinum electrode and the electrolyte is diluted with water so that grid electrodes were coated with mortar on the length.

The electrolysis was carried out for 10 min at a current strength of 0.5−1.0, And then 50 min at a current of 2−2. 5 A and a voltage of 2−3 In (while stirring). After bleaching of the solution add 0,1 g of urea, glass, walls of glass and protruding parts of the electrodes are then rinsed with water and electrolysis are in another 10 min. If svezhemorozhenoj portion of the cathode is not allocated copper, electrolysis is complete. Without turning off the current, the glass electrolyte is removed and the electrodes are quickly washed, successively immersing them in two cups of water for 10 s Then washed the electrodes with ethyl alcohol.

The cathode was dried at 105±5 °C for 5 min, cooled in a desiccator and weighed. By difference weighing before and after electrolysis calculate the mass of copper were planted.

The anode is dried for 5−7 min at 200±5 °C, cooled in a desiccator and weighed. By difference before and after the electrolysis calculate the mass of precipitated lead dioxide determine the mass fraction of lead.

(Changed edition, Rev. N 1, 2)

2.3.3. When lead content above 1% to the solution add 4 cmof sulphuric acid diluted 1:1, and the solution was cooled to 15−18 °C. the Precipitated lead sulphate is filtered through a dense filter, and washed 3−5 times with sulphuric acid, diluted 2:98. The volume was adjusted with water to 100 cmand further analysis are as indicated in claim 2.3.2.

(Changed edition, Rev. N 1).

2.4. Processing of the results

2.4.1. The content of copper () in percent is calculated by the formula

,

where is the mass of a platinum cathode before electrolysis, g;

 — the mass of the platinum cathode after electrolysis, g;

 — the weight of the portion,

2.4.2. Allowable absolute differences the results of the analysis shall not exceed the values specified in table.1.

Table 1

(Changed edition, Rev. N 2).

2.4.3. Lead content () in percent is calculated by the formula

,

where is the mass of the platinum anode to electrolysis, g;

is the mass of platinum of the anode after electrolysis, g;

 — weight of sample, g;

 — the conversion factor of lead dioxide on lead.

2.4.4. Allowable absolute differences the results of the analysis shall not exceed the values specified in table.2.

Table 2

(Changed edition, Rev. N 2).

3. PERIADOLESCENCE METHOD FOR THE DETERMINATION OF COPPER CONTENT IN LEAD BABBITS

3.1. The essence of the method

The sample is dissolved in a mixture of hydrochloric and bromatological acids with bromine. After removal of traces of oxidizing agent restores the copper to the monovalent iodide of potassium, it releases iodine in a solution of hydrofluoric acid is titrated with thiosulfate solution.

3.2. Reagents and solutions

Hydrochloric acid by the GOST 3118−77.

Bromatologia acid according to GOST 2062−77.

Acetic acid GOST 61−75, diluted 1:1.

Nitric acid GOST 4461−77.

Bromine according to GOST 4109−79.

Mix to dissolve: mix 45 cmof hydrochloric and 45 cmbromatological acid and carefully pour 10 cmof bromine.

Salt-vinegar mix; prepared as follows: to 200 cmof concentrated hydrochloric acid are added 150 cmof acetic acid diluted 1:1. The mixture was stored in a closed flask.

Ammonium hydrogen fluoride according to GOST 4518−75, a solution prepared as follows: 600 g of salt dissolved in 1 l of water. The solution was stored in a plastic container.

Potassium iodide according to GOST 4232−74, a solution of 200 g/DM.

The soluble starch according to GOST 10163−76, a freshly prepared solution of 10 g/DM.

Amyl alcohol or chloroform.

A standard solution of copper, prepared as follows: 0,500 g of electrolytic copper was dissolved in a beaker with a capacity of 400 to 500 cmin 10 cmof concentrated nitric acid, covering the beaker watch glass. After dissolution of sample of copper glass wash, heated solution prior to the removal of nitrogen oxides and reduced to 2−3 cm. The residue is diluted with water, transferred to a volumetric flask with a capacity of 500 cm, was adjusted to the mark with water and mix.

1 cmof the solution contains 1 mg of copper.

Chernovetskiy sodium (sodium thiosulfate) according to GOST 244−76, a solution of concentration 0.25 mol/l; prepared by dissolving 6.2 g of salt in 1 liter of distilled water containing 0.1 g of sodium carbonate.

To improve the stability of the solution add 5 cmamyl alcohol or 0.3 cmof chloroform.

(Changed edition, Rev. N 1, 2).

3.3. Analysis

3.3.1. A portion of the Babbitt weight of 0.5−1.0 g were placed in a glass with a capacity of 250−300 cm, flow 10 cmmixture for dissolving and after violent reaction is heated to dissolution. The solution was evaporated to dryness, boiling. The dry salt moistened with 10 cmof concentrated hydrochloric acid and evaporated to dryness also. Then salt moistened with 5 cmof concentrated hydrochloric acid and carefully, without over-heating the dry residue, remove excess of acid and its condensation on the inner surface of the glass.

The dry residue is cooled, dissolved in 3.5 cmsalt-vinegar mixture, which is accurately measured from a burette or pipette, pour the 12.5 cmof hot water, stirred and cooled.

Then, pipette, pour 5 cmof a solution of ammonium fluoride, washing them with the inner walls of the glass, stirred, poured 10 cmof a solution of potassium iodide and titrate the liberated iodine with sodium thiosulfate to a straw-yellow color of the solution. Then add 3−5 cmstarch solution and continue to titrate to the disappearance of blue color.

(Changed edition, Rev. N 1).

3.3.2. The installation of the mass concentration of sodium thiosulfate

Mass concentration set by the standard solution of salt of copper. For installation of the mass concentration of taking aliquots of 25,0 cmstandard solution, placed in a beaker with a capacity of 300−400 cmand carefully evaporated to dryness. Then the dry salt was treated twice with hydrochloric acid, priliva each time 5 cmand making sure that the salt after the second treatment did not pericallis had blue color. After cooling, pour all the reagents and continue the analysis as described in section 3.3.1.

The mass concentration of the solution () of thiosulfate on copper, expressed in g/cm, is calculated by the formula

,

where is the volume of sodium thiosulfate consumed in the titration, cm;

 — the volume of a standard solution of copper taken for the installation of the mass concentration, cm;

 — mass concentration of a standard solution of copper, g/cm.

(Changed edition, Rev. N 1, 2).

3.4. Processing of the results

3.4.1. The content of copper () in percent is calculated by the formula

,

where is the volume of sodium thiosulfate consumed in the titration, cm;

 — mass concentration of sodium thiosulfate on copper, g/cm;

 — the weight of the portion of the sample,

(Changed edition, Rev. N 1, 2).

3.4.2. Allowable absolute differences the results of the analysis shall not exceed the values given in table.3.

Table 3

(Changed edition, Rev. N 2).

4. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF COPPER CONTENT

4.1. The essence of the method

The method is based on selective absorption of light from a standard source of copper atoms. The solution is sprayed in an acetylene-air flame atomic absorption spectrometer and measure the absorbance at the wavelength of 324,7 nm.

4.2. Apparatus, reagents and solutions

Spectrometer of atomic absorption.

The glasses are made of PTFE with a capacity of 50 cm.

Nitric acid GOST 4461−77.

Hydrofluoric acid (hydrofluoric acid) according to GOST 10484−78.

The mixture of acids to dissolve: is prepared as follows: hydrogen fluoride and nitric acid mix with water in the ratio 2:3:5 respectively. The mixture was stored in a plastic container.

Hydrogen peroxide according to GOST 10929−76.

Electrolytic copper GOST 859−78*.
______________
* On the territory of the Russian Federation GOST 859−2001. — Note the manufacturer’s database.

A standard copper solution is prepared as follows: 0,1000 g of copper is dissolved in 20 cmof nitric acid, diluted 1:2 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 0.1 mg of copper.

4.3. Analysis

4.3.1. Depending on the copper content of a sample of tin babbit mass, given in table.4, is placed in a beaker made of PTFE with a capacity of 50 cmand poured in small portions to 10 cmof the mixture for dissolution, making sure that the reaction did not proceed rapidly. The decomposition of lead babbits is conducted as follows: a portion of the lead babbit mass, given in table.4, is placed in a beaker made of PTFE with a capacity of 50 cm, flow 10 cmof the mixture for dissolution, heated, add 10 cmof water, 2−3 drops of hydrogen peroxide and heated to complete dissolution, then the contents of the beaker cooled, poured into a measuring flask with volume capacity given in table.4, add the mixture to dissolve at the rate of 10 cmof a mixture of 50 cmof volume of the solution was adjusted to the mark with water and mix. The copper content of more than 0.5% select aliquot part of the solution, transferred to a volumetric flask in accordance with table.4, again add the mixture to dissolve, bring to the mark with water and mix.

Table 4

The obtained solution is sprayed in air-acetylene flame atomic absorption spectrometer and photometric at a wavelength of 324,7 nm, using as radiation source a lamp with a hollow cathode.

Fotometrirovanie for each sample is conducted three times. To the calculation should be the arithmetic mean of three dimensions based on the score obtained in fotomaterialy solution in the reference experiment.

The copper concentration set at the calibration schedule, fotometriya simultaneously with the analyzed solutions a series of solutions of known copper content.

4.3.2. To build a calibration curve in a volumetric flask with a capacity of 50 cm, measure off microburette 0; 0,5; 1,0; 2,0; 2,5 cmof a standard solution of copper, poured 10 cmof the mixture for dissolution, adjusted to the mark with water and mix. Photometric solutions, as specified in clause 4.3.1.

According to the obtained average values of absorbance and known concentrations of copper to build the calibration graph.

4.4. Processing of the results

4.4.1 the Content of copper () in percent is calculated by the formula

,

where is the concentration of copper was found in the calibration schedule, µg/cm;

 — volume fotometricheskogo solution, cm;

 — the initial breeding, cm;

 — the mass of sample, g;

 — aliquota part of the solution, with

m.

4.4.2 allowable Absolute differences the results of the analysis at a confidence level of 0.95, should not exceed the values given in table.5.

Table 5