GOST 1953.12-79
GOST 1953.12−79 Bronze tin. Methods for the determination of sulfur (with Amendments No. 1, 2)
GOST 1953.12−79
Group B59
INTERSTATE STANDARD
BRONZE TIN
Methods of determining sulphur
Tin bronze.
Methods for the determination of sulphur
AXTU 1709
Date of introduction 1981−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. The standard fully complies ST SEV 2239−80
4. REPLACE GOST 1953.12−74
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
The designation of the reference document, to which this links |
Section number, paragraph, sub-paragraph |
GOST 8.315−97 |
5.4, 6.4.3 |
GOST 83−79 |
2 |
GOST 613−79 |
Chapeau |
GOST 614−97 |
Chapeau |
GOST 1953.1−79 |
1.1 |
GOST 4159−79 |
2 |
GOST 4204−77 |
2 |
GOST 4220−75 |
2 |
GOST 4232−74 |
2 |
GOST 5017−74 |
Chapeau |
GOST 5583−78 |
2 |
GOST 9147−80 |
2 |
GOST 10163−76 |
2 |
GOST 20490−75 |
2 |
GOST 25086−87 |
1.1, 5.4, 6.4.3 |
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 iodometric method for the determination of sulphur and methods of sulfur determination using automatic analyzers (0.001% to 0.1%) in tin bronze according to GOST 5017, GOST GOST 613 and 614.
The standard fully complies ST SEV 2239−80.
(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).
2A. IODOMETRIC METHOD FOR THE DETERMINATION OF SULFUR
2A.1. The essence of the method
The method is based on the combustion of the sample in flowing oxygen at 1200−1250 °C with the absorption of evolved sulfur dioxide with water and titration of the resulting sulfurous acid solution of iodine in presence of starch.
Sec. 2A. (Added, Rev. N 1).
2. APPARATUS, REAGENTS AND SOLUTIONS
Installation for determination of sulfur content (see drawing).
Damn. Installation for determination of sulfur content
The installation consists of the following elements: oxygen cylinder 1; a pressure reducing valve 2; a gas washing bottle 3 with a solution containing 40 g/lof potassium permanganate and 400 g/DMof potassium hydroxide; a gas washing bottle 4 with sulfuric acid solution, diluted 5:100, columns for drying of oxygen-5, containing in the lower part of anhydrous calcium chloride, then a layer of glass or ordinary wool, and in the upper part of dry potassium hydroxide; the three-way tap 6, makes it possible to direct the oxygen passed clean, in the oven or let it go into the atmosphere and to further regulate the rate of oxygen transmission; a porcelain tube 7, inner diameter of 20 cm, the ends of which facing of a furnace should be a minimum length of 100 mm, calcined before use in an atmosphere of oxygen at 1200 °C; a horizontal electrical tube furnace with 8 silovymi rods, equipped with a thermostat with a thermocouple and galvanometer, allowing the heating up to 1200 °C, 9; dust collector filled with glass wool, 10; two-way tap 11; two absorption vessels 12, connected by glass bridges; 13 burettes with a capacity of 10 or 25 cm.
Unglazed porcelain boats N 2 according to GOST 9147. Pumps should be prepared for calcination at 1200 °C in an oxygen atmosphere for 10 min. the completeness of the burning of sulfur and its compounds from boats is controlled by passing the gaseous products from the furnace through a solution of starch. The end of burning sulphur is determined by the cessation of bleaching iodobromine solution.
Standard sample for setting the operating mode of the installation. Using the State standard samples of steels: GEO 716−84п of the bonds 1557−83п of the bonds 1640−83п of the bonds 888−84п of the bonds 1416−82п, or Nickel alloy, 1862−80 GSO, GSO 1862−85п of the bonds 1498−83п of the bonds 1609−85п.
Copper with a mass fraction of sulfur no more than 0.001% in the form of chips with thickness of 0.05−0.1 mm.
Potassium iodide according to GOST 4232 and a solution of 50 g/DM.
Potassium hydroxide.
Potassium permanganate according to GOST 20490, a solution of 40 g/DM.
Wash solution; prepared as follows: into a measuring flask with a capacity of 1 DMcontribute 40 g of potassium permanganate and dissolved in 500−600 DMwater; to the obtained solution was added 400 g of potassium hydroxide and after the dissolution and cooling the solution was diluted to the mark with water.
Sulfuric acid according to GOST 4204, diluted 5:100.
Mercury iodide.
Calcium chloride on HG, fused anhydrous.
The starch according to GOST 10163; a solution of 10 g/DM; prepared as follows: 10 g of starch is mixed with a small amount of water until a homogeneous mass. The starch suspension is poured while stirring into 1 inchof hot water. The solution was boiled for 2−3 min and filtered through a folded filter into the flask, which added 0.03−0.05 g of iodide of mercury.
Oxygen gas according to GOST 5583.
Potassium dichromate according to GOST 4220, 0,0125 mol/DMsolution. Prepared from the drug, recrystallized twice and dried at 170 °C.
The anhydrous sodium carbonate according to GOST 83.
Chernovetskiy sodium (sodium thiosulfate) 0,0125 mol/land 0.0005 mol/DMsolutions; 0,0125 mol/DMsolution is prepared 2−3 days before the establishment of the titer in the following manner: 6.2 g chernovetskogo sodium dissolved in 100 cmsvejeprokipachenna and cooled water, add 0.2 g of sodium carbonate, dilute with water to 1 DMand mix well; 0,0005 mol/DMsolution of sodium thiosulfate is prepared by dilution of 0.0125 mol/DMsolution: 10 cmof 0.0125 mol/DMsolution of sodium thiosulfate contribute in a volumetric flask with a capacity of 250 cm, and topped up with boiled and cooled water to the mark and mix. The solution is prepared the day of application.
The titer determination of sodium thiosulfate.
In a conical flask with a capacity of 250 cm tomake 10 cmsulfuric acid, 10 cmof a solution of potassium iodide, 25 cmof 0.0125 mol/DMsolution of potassium dichromate, and the flask closed ground stopper and leave in a dark place for 8−10 minutes and Then rinsed the walls of the bulb a small amount of water (total solution volume should be 70−80 cm) and titrated the liberated iodine with sodium thiosulfate until the color of solution becomes light yellow, then add 2 cm ofstarch solution and continue titration until the disappearance of blue color.
The mass concentration of 0.0125 mol/DMsolution of sodium thiosulphate by potassium dichromate () in grams is calculated by the formula
,
where — the amount of sodium thiosulfate consumed in the titration, sm.
Iodine crystal according to GOST 4159, of 0.0005 mol/DMsolution; prepared as follows: of 1.27 g of crystalline iodine and 2.5 g of potassium iodide is weighed into a porcelain Cup, stirred with a small amount of water, triturated with a pestle and dissolve in water. The solution was transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix. Solution store in a dark bottle with a glass stopper.
100 cmresulting solution was placed in a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix. The solution is prepared the day of application.
Of fiksanala of 0.0005 mol/DMsolution of iodine is prepared with the appropriate dilution of 0.005 mol/DMsolution of iodine.
The installation of the mass concentration of iodine solution.
The mass concentration of iodine solution sets for the standard sample of the alloy contains sulfur in a quantity close to the analyzed sample.
1 g of standard sample is placed in a porcelain boat. Pull the plug out from the tube and use the wire hook is installed in the most heated zone of the tube. Then do as described in sec. 4.
The titer of iodine solution (), expressed in grams of sulfur per 1 cmof a solution, calculated by the formula
,
where — weight of standard sample, g;
— mass fraction of sulfur in the standard sample, %;
— the volume of iodine solution consumed for titration, sm.
When no standard sample titer solution of iodine is determined by sodium thiosulfate, mass concentration of which is determined by solution of potassium dichromate.
The titer determination of iodine solution.
In a flask with a capacity of 250 cm18−20 cm pouredwater, poured from a burette 20 cmof iodine solution, dilute with water to 70−80 cmstirred and titrated to 0.0005 mol/DMsolution of sodium thiosulfate until then, until the color of solution becomes light yellow, then pour 2 cm ofstarch solution and continue titration until the disappearance of blue color.
The mass concentration of 0.0005 mol/DMsolution of iodine by sodium thiosulphate () in grams per 1 cmof a solution is calculated by the formula
,
where the titer of 0.0125 mol/DMsolution of sodium thiosulfate;
— the amount of sodium thiosulfate consumed in the titration, sm.
The titer of a solution of iodine sulphur (is) in grams per 1 cmof a solution is calculated by the formula
.
Sec. 2. (Changed edition, Rev. N 2).
3. PREPARATION FOR ASSAY
3.1. Prior to analysis it is necessary to check the tightness of the device at 1200 °C. For this purpose, connect the entire device with a balloon containing oxygen, open the three-way stopcock to the air, carefully open the cylinder valve, allow oxygen at a speed of 20−30 bubbles in 1 minute, switch the three-way valve to the position at which oxygen enters the furnace, and close the valve before the first absorption vessel. 2−3 min should stop the bubbling in the wash bottles, and then wait another 5−7 minutes If bubbles no longer stand out, consider installing tight.
Before testing check the porcelain tube for the presence of fugitive recovery agents. To do this in both the absorption vessel and pour 50 cmof water, 10 cmstarch solution and poured from the burette a few drops of iodine solution to the appearance of blue coloring. Then raise the furnace temperature to 1200 °C and pass a current of oxygen.
If after 4−5 min, the color of the solution in the first vessel is significantly weakened, then the solution is poured several drops of iodine to equalize coloration in both vessels.
4. ANALYSIS
4.1. 1 g of alloy are placed in a porcelain boat, pull the plug out of the tubes from the oxygen tank and using a wire hook set the boat in the most heated zone of the tube. The tube is quickly stoppered and allow oxygen with sufficient speed to prevent the formation of vacuum in the furnace.
When leaving the furnace in the absorption vessel gases begin to decolorize the iodine solution in the lower part of the vessel, pour the iodine solution at such a rate that the blue color did not disappear during burning of the sample.
With the weakening of the color intensity of the absorption solution to slow down the surging of iodine solution and stop altogether if the color of the solution remains constant and identical with the color of the solution in the right container. After that allow oxygen for 1 min, and if the color of the solution does not change, the combustion is considered ended.
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 a solution of iodine sulphur, g/cm;
— the weight of the portion,
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 the table.
Mass fraction of sulfur, % |
, % |
, % |
From 0.001 to 0.005 incl. |
0,0007 |
0,0009 |
SV. 0,005 «0,01 « |
0,0015 |
0,002 |
«Is 0.01» to 0.03 « |
0,003 |
0,004 |
«To 0.03» to 0.05 « |
0,005 |
0,007 |
«0,05» 0,1 « |
0,007 |
0,009 |
5.1, 5.2. (Changed edition, Rev. N 2).
5.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in the table.
5.4. Control of accuracy of analysis results is carried out according to State standard samples of steels or Nickel alloys (see sec. 2), re-approved by GOST 8.315, in accordance with GOST 25086.
5.3, 5.4. (Added, Rev. N 2).
6. THE METHOD USING AUTOMATIC AND SEMIAUTOMATIC ANALYZERS
6.1. The essence of the method
The method is based on determination of sulfur by using automatic or semi-automatic analyzer that ensures the burning of the sample the sample of bronze in flowing oxygen at 1200−1600 °C, the absorption of the formed sulphur dioxide with a solution of oxidizer and the determination of sulfur depending on the type of analyzer, conductometric, coulometric, or amperometric methods to measure the molecular absorption bands of sulphur dioxide in the infrared region of the spectrum.
6.2. Equipment
Automatic or semi-automatic analyzer of the type as-7932. Allowed to use other types of automatic or semi-automatic analyzers.
6.3. Analysis
Determination of the mass fraction of sulfur is carried out according to the methods prescribed for this type of analyzer using the calibration state standard samples of steel, for example a set consisting of a GEO 716−84п of the bonds 164−84п of the bonds 888−84п of the bonds 1377−82п and GSO 1416−82п or Nickel alloys (see sec. 2).
6.4. Processing of the results
6.4.1. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for 3), specified in the table.
6.4.2. Discrepancies in the results analysis, obtained in two different laboratories or two of the results obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in the table.
6.4.3. Control of accuracy of analysis results is carried out according to State standard samples of steel or Nickel alloys (see sec. 2 and 6.3), re-approved by GOST 8.315, in accordance with GOST 25086.
Sec. 6. (Changed edition, Rev. N 2).