GOST 15483.7-78
GOST 15483.7−78 (ST SEV 4813−84) Tin. Method for the determination of sulfur (with Amendments No. 1, 2, 3)
GOST 15483.7−78
(CT CMEA 4813−84)
Group B59
INTERSTATE STANDARD
TIN
Method for the determination of sulfur
TP.
Method for determination of sulphur
AXTU 1709
Date of introduction 1980−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
B. C. Baev, T. P. Almanova, G. M. Vlasov, C. B. Meshkova, L. V. Mishchenko, L. D. Savilov, R. D. Kresnicka
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. The standard complies ST SEV 4813−84 in part iodometric method
4. REPLACE GOST 15483.7−70
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Section number, paragraph |
| GOST 8.010−90 |
1.2 |
| GOST 4159−79 |
2 |
| GOST 4232−74 |
The same |
| GOST 4328−77 |
« |
| GOST 5583−78 |
« |
| GOST 9147−80 |
« |
| GOST 15483.0−78 |
1.1 |
| GOST 20490−75 |
2 |
| GOST 24363−80 |
The same |
| GOST 27068−86 |
« |
6. Limitation of actions taken by Protocol No. 4−93 of the Interstate Council for standardization, Metrology and certification (ICS 4−94)
7. REVISED (April 1999) with Amendments No. 1, 2, 3, approved in August 1984, October 1985, June 1989 (IUS 12−84, 1−86, 10−89)
This standard specifies iodometric method for the determination of sulphur content (in mass fraction of sulfur from 0.001 to 0.06%) in tin all brands except tin of high purity.
The method is based on the combustion of a sample of tin in a current of oxygen at 1200 °C. the Sulfur burns to sulfur dioxide, which absorb water, and the resulting sulphuric acid titrated solution of iodine in presence of starch indicator.
Standard meets CT CMEA 4813 in part iodometric method.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis and security requirements — according to GOST 15483.0.
(Changed edition, Rev. N 1).
1.2. Allowed the use of methods for the determination of sulfur content using automatic analyzers certified according to GOST 8.010* and is not inferior in accuracy specified in the standard.
________________
* On the territory of the Russian Federation GOST R 8.563−96.
(Added, Rev. N 1).
2. APPARATUS, REAGENTS AND SOLUTIONS
Installation for determination of sulfur content (see drawing).
The installation consists of a oxygen cylinder 1; a pressure reducing valve 2; bottles for cleaning oxygen 3, 4; drainage column 5; the three-way tap 6; horizontal electric tube furnace 7 sheltowee terminals that provide heating to 1200 °C, equipped with rheostat and ammeter; thermocouple 8; galvanometer 9; unglazed porcelain tube 10 an inner diameter of 15−20 mm and such a length that the ends thereof protrude from the furnace at 180−200 mm; clamp 11 dust collector 12, is filled with glass wool; 13 burettes with a capacity of 25 cm; bottles of dark glass 14 storage titrated solution of iodine; absorption apparatus 15.
Boats unglazed porcelain GOST 9147 length 70−130 mm, a width of 7−12 mm and a height of 5−10 mm.
Potassium iodide according to GOST 4232, a solution with a mass fraction of 5%.
Iodine GOST 4159, titrated (½
)=0.005 mol/DM
solution: in a volumetric flask with a capacity of 1 DM
put a 2.5−3 g of potassium iodide, dissolved in 4−5 cm
of water, add 0,6350 g of iodine and dissolve with stirring. Further dilute to the mark with water and mix. Solution store in a sealed bottle of dark glass.
Potassium hydroxide according to GOST 24363 or sodium hydroxide according to GOST 4328 and a solution with a mass fraction of 40%.
Potassium permanganate according to GOST 20490, solution with a mass fraction of 4% solution of potassium hydroxide or sodium hydroxide with a mass fraction of 40%.
Starch soluble, a freshly prepared solution with a mass fraction of 1%.
A standard sample of the metal or alloy with a known sulphur content.
The calcium chloride.
Oxygen gas according to GOST 5583.
Wool glass.
Sodium Chernovetskiy according to GOST 27068.
The mass concentration of iodine solution set on a standard sample of the metal or alloy, similar in sulfur content to the sample carried through all stages of analysis, or solution servational sodium, prepared with standard-titre the concentration.
(Changed edition, Rev. N 1, 2, 3).
3. PREPARATION FOR ASSAY
3.1. For analysis setting collected, as shown in the drawing.
3.2. Before Assembly, installation bottles to clean oxygen coming into the oven, fill with a solution of potassium hydroxide with a mass fraction of 40% potassium permanganate solution with a mass fraction of 4%.
To dehumidify the oxygen column 5 is first filled with calcium chloride, then a layer of glass wool and then dry with a hydroxide of potassium or sodium. The collector 12 is filled with glass wool.
In the absorption device 15, consisting of two identical vessels are connected by glass bridges, before combustion of the sample flow 50 cmwater, 10 cm
starch solution and a few drops of iodine solution to the same blue color. The right vessel is designed for monitoring the titration in the left absorption vessel.
(Changed edition, Rev. N 1, 2, 3).
3.3. Mounted thermoelectric pyrometer for measuring the temperature inside the furnace, consisting of a platinum-rhodium thermocouple 8 and galvanometer 9.
3.4. A porcelain tube 10 prior to use is calcined at 1200 °C in an oxygen atmosphere. In these conditions, calcined porcelain boats.
The completeness of burning of sulfur and its compounds from pumps controlled by passing the gaseous products from the furnace through ikramullah solution absorption apparatus. The end of burning sulphur is determined by the termination of the bleaching solution.
3.5. Before analysis, the entire system check for leaks when heated to 800−900 °C oven. To do this, open the three-way valve 6 with the release of the air, open the container and allow oxygen at a speed of 20−30 bubbles in 1 min. Switch off crane 6, flowing oxygen into the furnace, disconnect the clip with a porcelain pipe from the absorption vessel and, if after 5 min, the bubbles do not stand out, consider installing tight.
3.6. Installation check for the presence of fugitive recovery agents. To do this in both vessels (absorption and control) pour 50 cmwater and 10 cm
starch solution with a mass fraction of 1%. Poured from a burette in both vessels the same number of drops of iodine solution to the blue staining, the oven is heated to 1200 °C and pass a current of oxygen. If the colour of the solution in the absorption vessel disappears, then poured to the solution drop by drop until the iodine solution until the blue color of the solution will not cease to disappear and become equal in intensity with the color of the solution in the right container.
(Changed edition, Rev. N 3).
4. ANALYSIS
4.1. The weight of tin weight of 2,0000 g placed in a porcelain boat, pre-calcined in flowing oxygen and cooled in a desiccator.
The boat with the hitch with a long wire hook is placed in a pipe for combustion in the most heated zone. The tube is quickly stoppered and weighed tin burn. When it starts burning, the current oxygen needs to be fast enough to prevent the formation of vacuum in the furnace.
When leaving the furnace the gases begin to discolour the iodine solution at the bottom of the absorption vessel from the burette add a solution of iodine with such speed that the blue color of the solution did not disappear.
At the end of the burning adding a solution of iodine slows and is stopped completely when the blue color of the solution in the absorption vessel will be constant and the same intensity with the color of the solution in the right container. After that allow oxygen in over a minute, and if the color of the solution disappear, the burning is complete.
(Changed edition, Rev. N 2).
4.2. (Deleted, Rev. N 2).
5. PROCESSING OF THE RESULTS
5.1. Mass fraction of sulfur () in percent is calculated by the formula
where is the volume of iodine solution consumed for titration, cm
;
— mass concentration of iodine solution, expressed in grams of sulfur, g/cm
;
— weight of tin,
(Changed edition, Rev. N 3).
5.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence probability of 0.95 should not exceed the values given in the table.
| Mass fraction of sulfur, % | The absolute allowable difference, % |
| From 0.001 to 0.003 |
0,0005 |
| SV. Of 0.003 «to 0.005 |
0,001 |
| «0,005» 0,01 |
0,002 |
| «0,01» 0,02 |
0,004 |
| «To 0.02» to 0.06 |
0,005 |
(Changed edition, Rev. N 1, 2).
