GOST 21877.2-76

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  ГОСТ 21877.2-76

GOST 21877.2−76 Babbit tin and lead. Method for the determination of tin (with Amendments No. 1, 2)

GOST 21877.2−76

Group B59

STATE STANDARD OF THE USSR

BABBIT TIN AND LEAD

Method for determination of tin

Tin and lead babbits. Method for the determination of tin*

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 1380.2−70

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 a termination 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


APPROVED AND promulgated by the Decree of the USSR State Committee for standards from 25.06.87 N 2463


This standard applies to babbit tin and lead grades B16, bn, BS6 and sets the volumetric method for the determination of tin (with tin content of 5 to 20%).

The method is based on dissolving the sample in sulfuric acid. After adding hydrochloric acid copper and antimony recover metallic iron and filtered. The tin in the filtrate are reduced by aluminium or lead, and then determine by iodometric titration.

(Changed edition, Rev. N 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 21877.0−76.

2. APPARATUS, REAGENTS AND SOLUTIONS

The shutter of Haeckel (see drawing).

Soda shutter Haeckel serves for protection of divalent tin from oxidation by air oxygen. The shutter is inserted into the throat of the flask with a rubber tube filled with saturated solution of sodium bicarbonate.

Sulfuric acid according to GOST 4204−77.

Hydrochloric acid by the GOST 3118−77.

Sodium bicarbonate according to GOST 4201−79, saturated solution.

Lead brand WITH GOST 3778−77*, granulated or in plates, rolled into a spiral. The lead used for the analysis many times, for what it is before use, boil for 5−10 minutes in hydrochloric acid diluted 1:1, then washed with water.
___________________
* On the territory of the Russian Federation GOST 3778−98. — Note the manufacturer’s database.

Aluminium metal according to GOST 11069−74* and GOST 11070−74 in the form of slices or chips brands A99, A95 or A97.
____________________
* On the territory of the Russian Federation GOST 11069−2001 — note the manufacturer’s database.

Iron metal in the form of soft spirals or small nails. Nails calcined to remove oil, washed with hydrochloric acid diluted 1:1, and tested for the presence of tin, zinc and cadmium. Nails used for the analysis several times, which before eating them boil for 1−2 minutes in hydrochloric acid diluted 1:1, then washed with water.

Tin stamps O1 or VHF GOST 860−75.

Potassium iodide according to GOST 4232−74.

Iodine GOST 4159−79, 0,05 n solution*; prepared as follows: 40 g of potassium iodide dissolved in 35−40 cmof water in the conical flask with a capacity of 150−200 cmwith a glass stopper. In solution give 6.5 g of metallic iodine and mix until dissolved. The solution is poured into a measuring flask with volume capacity of 1 liter, dilute to the mark with water and mix. Solution store in a dark bottle. The mass concentration of the solution set on the metal tin after 10−15 days.
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* Change No. 2 proposed in item 2, replace the words «of a 0.05 n solution of iodine» «iodine solution of concentration 0.05 mol/DM». — Note the manufacturer’s database.

The water-soluble starch according to GOST 10163−76, a freshly prepared solution of 10 g/DM: 1 g of soluble starch, triturated in a mortar with 10 cmwarm water, poured in 90 cmof boiling water, boil for 3−5 minutes and cooled.

(Changed edition, Rev. N 1, 2).

3. ANALYSIS

3.1. In a conical flask with a capacity of 250 cmis placed a portion of the Babbitt weight of 0.5 g, poured 20 cmof concentrated sulfuric acid and heated to the Stripping of sulfur from the walls of the flask, the complete dissolution of the samples and whitening the precipitate at a temperature of vapors escaping sulfur dioxide. Then the flask was cooled, carefully poured 100 cmof water, 20 cmof hydrochloric acid, add 20−30 grams of small iron nails and lead recovery when heated in a water bath for about 1 h prior to the allocation of copper and antimony in the form of a metal sponge. The solution was filtered through a cotton pad and washed with 20−30 cmhot hydrochloric acid, diluted 1:9.

(Changed edition, Rev. N 1).

3.2. The clear solution was poured 20 cmof concentrated hydrochloric acid and 2.0 to 2.5 g of metallic aluminum in small portions. After 30 minutes pour another 20 cmof hydrochloric acid, heated to boiling and boiled until complete dissolution of excess aluminum and sponge the separated tin. The flask is removed from the plate, quickly close the shutter of Haeckel, fill it with saturated solution of sodium bicarbonate and cooled in running water, making sure that the shutter was all the time filled with a solution of sodium bicarbonate.

With cooling the flask quickly removed the stopper, poured 3−5 cmstarch solution and titrated tin iodine solution of concentration 0.05 mol/DMto slightly blue color.

(Changed edition, Rev. N 1, 2).

3.3. When you restore the lead to the solution after separation of copper and antimony added 20 cmof concentrated hydrochloric acid, 50 g of lead in the form of pellets or coils, and are in recovery within 30 minutes at weak boiling, having closed the flask with a watch glass. 5 minutes prior to the end of the recovery flask closed with a stopper of Haeckel, filled with sodium bicarbonate. At the end of the recovery solution was cooled in running water and further analysis are as indicated in claim 3.2.

(Changed edition, Rev. N 1).

3.4. The installation of the mass concentration of iodine solution

The mass concentration of iodine solution set in metal tin. For this 0.1 g of tin are placed in a conical flask with a capacity of 250 cm, dissolved in 20 cmof concentrated sulfuric acid, cooled, poured 100 cmof water, 20−25 cmof hydrochloric acid and, depending on the choice of the reducing agent, continue with the analysis as described in section 3.2 or 3.3.

A bulk solution concentration of 0.05 mol/DMiodine tin, expressed in g/cm, is calculated by the formula

,

where is the mass of the hanging tin metal, g;

 — volume of 0.05 n iodine solution consumed for titration of tin, cm.

(Changed edition, Rev. N 1, 2).

4. PROCESSING OF THE RESULTS

4.1. The contents of the tin () in percent is calculated by the formula

,

where  — volume of the iodine solution of concentration 0.05 mol/DMconsumed for titration, cm;

 — mass concentration of a solution of 0.05 mol/DMiodine tin, g/cm;

 — the weight of the portion of the sample,

(Changed edition, Rev. N 1, 2).

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