GOST 1652.9-77
GOST 1652.9−77 Alloys copper-zinc. Method for the determination of sulfur (with Amendments No. 1, 2, 3)
GOST 1652.9−77
Group B59
STATE STANDARD OF THE USSR
ALLOYS COPPER-ZINC
Methods of determining sulphur
Copper-zinc alloys.
Methods for the determination of sulphur
AXTU 1709
Date of introduction 1978−07−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
Y. F. Chuvakin, M. B. Taubkin, A. A. Nemodruk, N. In. Egiazarov (supervisor), I. A. Vorobyev
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. REPLACE GOST 1652.9−77
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
The number of the paragraph, subparagraph |
| GOST 8.315−91 | 4.2 b 5.6 |
| GOST 859−78 |
Sec. 2 |
| GOST 1020−77 |
Chapeau |
| GOST 1652.1−77 |
1.1 |
| GOST 4232−74 |
Sec. 2 |
| GOST 4328−77 |
Sec. 2 |
| GOST 4404−78 |
Sec. 2 |
| GOST 10163−76 |
Sec. 2 |
| GOST 15527−70 |
Chapeau |
| GOST 17711−93 |
Chapeau |
| GOST 20490−75 |
Sec. 2 |
| GOST 25086−87 |
1.1, 4.2 b 5.6 |
| ISO 7266−84 |
The introductory part, the application |
5. Resolution of the state standard from
6. REPRINT (July 1997) with Amendments No. 1, 2 approved in October 1981, November 1987-December 1992 (IUS 12−81, 2−88, 3−93)
This standard specifies iodometric, titrimetric method and the method using automatic and semiautomatic analyzers (mass fraction of sulfur with from 0.001 to 0.05%) in copper-zinc alloys according to GOST 15527, GOST and GOST 17711 1020.
May be performed for the determination of sulfur in copper-zinc alloys according to ISO 7266* (see Annex).
________________
* Access to international and foreign documents referred to here and hereinafter, can be obtained by clicking on the link to the site shop.cntd.ru. — Note the manufacturer’s database.
(Changed edition, Rev. N 2, 3).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 25086 with the Supplement according to claim 1.1 GOST 1652.1.
(Changed edition, Rev. N 2).
2A. Iodometric titrimetric method
2A.1. The essence of the method
The method is based on combustion in a current of oxygen at 1000−1200°C, the absorption of emitted sulfur dioxide and titration of the resulting sulfurous acid solution of iodine in presence of starch indicator.
2A, 2A.1. (Added, Rev. N 2).
2. APPARATUS, REAGENTS AND SOLUTIONS
Installation for determination of sulfur content (see drawing).
Installation for determination of sulfur content
The installation consists of the following elements: oxygen cylinder 1 provided with a pressure reducing valve 2 (for regulating the rate of supply of oxygen in the furnace). the flask Tishchenko 3 with flushing solution; the absorption flask 4 containing concentrated sulfuric acid; column 5 for the dehydration of oxygen, containing in the lower part of dry chloride of calcium, then a layer of glass or ordinary wool, and in the upper part of dry caustic potash or a dry caustic soda; three-way tap 6 for controlling the rate of oxygen transmission; a porcelain tube 7 with a length of 650−750 mm, an inner diameter of 15−20 mm. tube Length should be such that to the ends of it were out of the oven no less than 180−200 mm. Tube before use, must be calcined at 1100−1200°C in an oxygen atmosphere; the temperature regulator 8 to maintain the desired temperature in a furnace consisting of a platinum-rhodium thermocouple and galvanometer; a horizontal tubular electric furnace 9, which can be heated to 1100−1200°C; dust collector 10, is filled with glass wool; two-way tap 11; burettes 13; absorption apparatus 12, consisting of two equal vessels, connected by glass bridges. The left vessel is the absorption in the lower part there is a drain valve at the end of the analysis of the absorption liquid is titrated. In the right vessel to pour the liquid used to control.
Unglazed porcelain boat length 70−130 mm, a width of 7−12 mm and a height of 5−10 mm. Pumps should be calcined at 1100−1200°C in an oxygen atmosphere for 10 min.
Iodine of 0.0005 mol/DMsolution; prepared as follows: 0,126 g of metallic iodine, purified by sublimation, is transferred to a small flask with a glass stopper, which had previously placed 2 g of potassium iodide and 5−10 cm
of water. The contents of the flask frequently shaken until complete dissolution of the iodine, then the solution was transferred to a volumetric flask with a capacity of 1 DM
and dilute to the mark with water. Keep the solution in a flask made of dark glass.
The mass concentration of iodine solution , expressed in g/cm
sulfur, calculated according to 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
.
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 brand M0k according to GOST 859 in the form of chips.
The soluble starch according to GOST 10163, 10 g/lsolution.
Potassium iodide according to GOST 4232.
Potassium hydroxide (potassium hydroxide) solution of 400 g/DM.
Sodium hydroxide according to GOST 4328.
Potassium permanganate according to GOST 20490, a solution of 40 g/DM.
Sulfuric acid according to GOST 4204.
Potassium chloride, anhydrous is processed.
Wash solution; prepared as follows: 40 g of potassium permanganate dissolved in 40% strength solution of potassium hydroxide.
Before testing the entire installation shall be tested for leakage at 1100−1200°C, which connect the entire device with a container, open three-way stopcock to the air, carefully open the container and allow oxygen at a speed of 20−30 bubbles per minute. Tap switch 6 so that the oxygen entered into the furnace and close the valve 11. 2−3 min should stop the bubbling in cleaning jars 3 and 4, wait another 5−7 minutes and, if the bubbles are no longer selected, the installation believe to be airtight.
(Changed edition, Rev. N 2, 3).
3. ANALYSIS
3.1. A fine suspension of alloy weighing 2.5 g placed in a porcelain boat and add shavings of copper, 0.3 g to Collect the entire installation as shown in the drawing, and then check for the recovery of volatile substances in sightlines tube. To do this in both the absorption vessel apparatus 12 is poured at 50 cmwater and 10 cm
starch solution, poured from a burette into both vessels a few drops of iodine solution to the appearance of weak blue color heat oven to 1080−1100°C and allow oxygen at a speed of 40−50 bubbles per minute.
If after 4−5 min, the color of the solution in the absorption vessel disappears, then it shows in the selection in the receiver the recovery of gaseous substances that react with iodine. In this case, without interrupting the current oxygen flow to the solution in the left vessel a few drops of iodine solution until then, while the weak blue color of the solution will remain unchanged and equal to the intensity of the color in the reference experiment in the right vessel. After that, pull the plug out from the tube (from oxygen cylinder) and placed in a tube boat with weighed sample with a long wire hook in the center of the oven (the hottest area). The tube is immediately stoppered and produce combustion.
When leaving the furnace in the absorption vessel gases begin to decolorize the iodine solution at the bottom of the vessel for absorption, pour the iodine solution at such a rate that the blue color of the solution disappeared during combustion. With the weakening of the color intensity of the absorption solution surging of iodine solution slow down and stop in that moment, when the weak blue color of the solution left in the vessel remains constant and is equal in intensity with the color of control solution in the right container. After that allow oxygen for 1 min, and if the color of the solution disappear, the burning is complete. In determining the sulphur content must be made in same-day control experience for an amendment. For this purpose the boat is calcined with 0.3 g of copper. Amendment to the control of experience should not be more than 0.2−0.3 cmof iodine solution.
3.2. (Deleted, Rev. N 2).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of sulfur in percent is calculated by the formula
where is the volume of iodine solution consumed for titration of sample, cm
;
— the volume of iodine solution consumed for titration of the solution in the reference experiment, cm
;
— mass concentration of iodine solution, expressed in g/cm
sulfur;
— the weight of the portion of alloy,
4.2. The absolute discrepancies in the results of parallel measurements ( — convergence) must not exceed the permissible values specified in the table.
| Mass fraction of sulfur, % |
|
|
| From 0.001 to 0.002 incl. |
0,0004 |
About 0.0006 |
| SV. 0,002 «0,004 « |
About 0.0006 | 0,0008 |
| «Of 0.004» to 0.01 « |
0,0008 |
0,001 |
| «Is 0.01» to 0.03 « |
0,003 |
0,004 |
| «0,02» 0,05 « |
0,005 |
0,007 |
4.2. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (the reproducibility) shall not exceed the values given in the table.
4.2, 4.2 a. (Changed edition, Rev. N 2, 3).
4.2 b. The control accuracy of the analysis carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOE) steel, Nickel and copper-zinc alloys, approved under GOST 8.315, in accordance with GOST 25086.
(Changed edition, Rev. N 3).
4.3. If there is discrepancy method is used with the use of automatic analysers.
(Added, Rev. N 1).
5. THE METHOD USING AUTOMATIC AND SEMIAUTOMATIC ANALYZERS
5.1. The essence of the method
The method is based on determination of sulfur by means of automatic and semi-automatic analyzer that ensures the burning of the sample the sample of the alloy in a current of oxygen at 1000−1200°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, amperometric methods to measure the molecular absorption bands of sulphur dioxide in the infrared region of the spectrum.
5.2. Equipment
Automatic or semi-automatic analyzer of the type as-7932. Allowed to use other types of automated or semi-automated analyzers to ensure the specified accuracy of the analysis.
5.3. 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 of the bonds 1416−82п or Nickel alloys: 1862−80 GSO, GSO 1498−83п of the bonds 1609−85п.
5.1−5.3. (Added, Rev. N 2).
5.4. The absolute discrepancies in the results of parallel measurements ( — convergence) must not exceed the permissible values specified in the table (see p.4.2).
5.5. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (the reproducibility) shall not exceed the values given in the table (see p.4.2).
5.4, 5.5. (Changed edition, Rev. N 2, 3).
5.6. The control accuracy of the analysis carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOE) steel, Nickel and copper-zinc alloys, approved under GOST 8.315, in accordance with GOST 25086.
(Changed edition, Rev. N 3).
APPLICATION (recommended). ISO 7266−84 Copper and copper alloys. Sulfur determination. Titrimetric method with burning
APP
Recommended
1. Scope
The standard specifies a titrimetric method for the determination of sulphur in copper and copper alloys combustion.
The method is applicable when the mass fraction of sulfur, more than 0,010%.
2. The essence of the method
Burn weighed sample in oxygen at 1250 °C. Absorb the resulting combustion gases are diluted with a solution of hydrogen peroxide. Titrate the resulting sulfuric acid borate of sodium, in the presence of a solution of a mixed indicator of methyl red and methylene blue.
3. Reagents
The analysis used reagents qualifications h. d. a. and distilled water or deionized water.
3.1. Hydrogen peroxide, a solution of 3 g/DM.
Dilute 10 cmof hydrogen peroxide (30% by weight) to 1000 cm
water.
3.2. Sulfuric acid, a solution of 0.0025 mol/DM.
14 cm dilutesulfuric acid (
) to 1000 cm
. Then diluted with 10 cm
of this solution to 1000 cm
.
3.3. Borate of sodium, standard solution
Dissolve 1,1895 g of sodium borate (NaB
O
·10H
O) in water and diluted to the mark in a volumetric flask with a capacity of 1000 cm
.
1 cmstandard solution contains 100 µg of sulfur.
3.4. Mixed indicator
Dissolve 0,120 g of methyl red and 0,080 g of methylene blue in 100 cmof ethanol.
4. Equipment
Common laboratory apparatus with the Supplement.
4.1. Burette 25 cmwith a scale division of 0,05 cm
.
4.2. Apparatus for the determination of sulfur (hell.1), consisting of the following parts
Apparatus for determining sulfur
Damn.1,
tube for purification of gas;
— Barbara tube;
— an output tap;
— pressure regulator and flow meter;
rubber coupling;
— a cooling coil;
— incinerator;
— the mercury stopper and protective tube;
— the two-way valve;
— buffer tank to equalize the pressure;
— a tube for burning
4.2.1. Oxygen bottle with pressure regulator and flow meter . Oxygen, shall not contain sulfur.
4.2.2. Tube for purification of the gas (and
). The tube is
filled with asbestos, treated with sodium hydroxide. The lower part of the tube
three-quarters of the height filled with phosphorus pentoxide. These two chemicals separated by a plug of glass wool.
4.2.3. Double faucet with pipes with a diameter of 3−4 mm, allowing the oxygen to enter the tube
for combustion, and gases released by burning, to enter the tube-bubbler
.
4.2.4. Mercury stopper with equilibrium flask and safety tube. The level of mercury using the equilibrium bottles is set so that in the presence of isolation while the water
solution from the tube for flaring was done with flow rate of 2.5 DM
/min While the water is
pressurized and mercury the shutter works to achieve a normal pressure.
4.2.5. A buffer tank for equalizing the pressure.
4.2.6. Tube for burning , made of non-porous heat resistant material, into which is placed the boat with the sample for burning.
4.2.7. Boat for burning, pre-calcined at 1250 °C in flowing oxygen.
4.2.8. Tube furnace , capable of maintaining the temperature of the heated portion of the tube for the combustion of
1250 °C, With cooled metallic head tube for burning (Fig.3).
4.2.9. Lead glass tube of the same diameter as the tube to burn , connected with a pipe for the combustion the rubber coupling
.
4.2.10. Water-cooled coil for cooling the gases released during the combustion.
4.2.11. Flexible plastic tube for all permanent connections.
4.3. Apparatus for absorbing gases, consisting of the following parts (Fig.1 and 2).
Apparatus for absorbing gases
Damn.2
Damn.3
1 — expanding to a width of 10 mm; 2 — copper tube 6x4, soldered; 3 — entry of oxygen;
4 — flange connection; 5 — copper tube for the water transmission 6x4; 6 — heat-resistant tube;
7 — glass tube with the same radius, in accordance with the external size of the tube
for burning; 8 — brazing; 9 — retainer
4.3.1. Absorption vessel with a capacity of 250 cm.
4.3.2. Barbara tube with holes of 0.05 mm from one end (Fig.2), immersed in a solution of hydrogen peroxide.
4.3.3. The exit valve between the tubes for the purification of gas
and
and barbotine tube
. With the help of this faucet you can maintain a small flow of oxygen in the absorption vessel, thus preventing the penetration of hydrogen peroxide solution in barbotine up
.
5. Analysis
5.1. Linkage samples
Weigh (1±0,001) g of the sample into the boat to burn. In alloys with a high zinc content (brass) added to the boat to charge five times the amount by weight of pure tin.
5.2. Blank sample
The calcination tube for combustion and boats for combustion eliminates the need for blank sample, but for alloys with a high content of zinc is carried out of a single sample with the same amount by weight of tin in the boat to burn.
5.3. The method of determining
Heat oven to 1250 °C. Making sure the coil cooling
is working, connect a pipe to burn
at both ends.
Open the taps and
and pass through the system and oxygen flow rate is 2.5 DM
/min by adjusting it using a pressure regulator and flowmeter
.
Close the valve and reduce the flow of oxygen to 0.5 DM
/min with a crane
. In the absorption vessel is introduced 40 cm
of hydrogen peroxide solution, 160 cm
of water and 4 to 6 drops of mixed indicator solution. Barbotine immerse the tube
into the solution. If necessary, bring the indicator to the purple color by the addition of sulfuric acid.
Open the valve and pass through the system and oxygen flow rate is 2.5 DM
/min for 2 min to expel carbon dioxide. If necessary, adjust the pressure regulator and flow meter
.
Close the valve and add in the absorption vessel the sodium borate. The led color should change from purple through blue to green. Stop adding the solution when the color indicator will change from blue-green to bright green.
Remove the stopper head of the furnace. Place a boat for burning, containing a portion of the sample, in the most hot zone of the furnace with the help of the rod of heat resistant metal.
Stoppered the tube for flaring and wait 2 minutes and Slowly open the faucet . Allow oxygen through a tube to burn for 2 minutes, then close the valve
. Take the plug out, and then the boat to burn.
The solution in the absorption vessel, titrated with sodium borate to the bright green color of the indicator.
5.4. A control measurement
Preliminary test of the apparatus was carried out using a standard sample or a synthetic sample containing known amounts of sulfur. The determination is carried out in accordance with the PP.5.1−5.3.
6. Processing of the results
Mass fraction of sulfur in percent is calculated by the formula
where — the amount of sodium borate used for titration, cm
;
— weight of sample, g;
0,0001 — weight sulfur, corresponding to 1 cmof sodium borate,
In alloys with a high content of zinc calculated mass fraction of sulfur should be reduced to the mass fraction of sulfur in blank sample tin.
7. Remarks to the method of determining
7.1. The analysis of copper alloys with a high zinc content
The method can be used for copper alloys with a high zinc content, in particular, to copper-zinc alloys (brass). In the analysis of such alloys in the boat to burn to the weighed sample is added five times the amount by weight of pure tin.
If this precaution is not observed, the zinc when heated to peregonets and the resultant oxide of zinc will interfere with the determination of sulfur.
7.2. Pre-treatment of the tubes for combustion
The tube needs to be calcined in the combustion temperature (1250°C) or by moving the tube in a furnace along its length.
7.3. Calcination of boats to burn
Calcination should be performed on the same day, when the boat is used. Boats must be stored in a desiccator. The absence of sulphur should be tested using the idle experiments.
7.4. Re-definition
At the same barbotine tube and the same absorption solution, you can perform a series of 5 or 6 determinations. To reduce time losses to a minimum, the following linkage you can enter immediately, as soon as the burning of the previous sample, and the titration can be carried out during a two-minute pause.
8. Analysis report
Report on the analysis shall contain:
the method of sampling;
the applied method of analysis;
the obtained results and the method of their calculation;
all the characteristic features observed in the analysis;
all done by operations not covered by this standard, or considered adverse.
APP. (Added, Rev. N 3).
