GOST 14339.1-82
GOST 14339.1−82 Tungsten. Methods for determination of carbon (Change No. 1)
GOST 14339.1−82
Group B59
INTERSTATE STANDARD
TUNGSTEN
Methods for determination of carbon
Tungsten. Methods for the determination of carbon
AXTU 1709
Date of introduction 1984−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
V. I. Veprintsev, S. N. Suvorova, N. With. Borodin, L. V. Mikhailov, V. V., Sultanian, N. P. Anikeeva, S. A. Isaev, V. I. Vinogradov, V. E. Chebotarev, V. A. Prilepskaya, A. Y. Abramov, N. B. Denisov, L. M. Efimov, K. Z. Stegenga
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. REPLACE GOST 14339.1−74
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Item number |
| GOST 435−77 |
2.2 |
| GOST 3760−79 |
2.2 |
| GOST 4107−78 |
2.2 |
| GOST 4108−72 |
2.2 |
| GOST 4234−77 |
2.2 |
| GOST 5583−78 |
2.2 |
| GOST 9147−80 |
2.2, 3.2 |
| GOST 18300−87 |
2.2, 3.2 |
| GOST 20478−75 |
2.2 |
| GOST 29103−91 |
1.2 |
5. The expiration time limit is removed by the Resolution of Gosstandart from
6. REVISED (June 1999) Change 1, approved in April 1988 (I & C 7−88)
This standard specifies the potentiometric and coulometric methods for determination of carbon in metallic tungsten, tungsten oxide, ammonium paratungstate and tungsten acid (when the mass fraction of carbon from 0.0005 to 0.5%).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 29103.
2. POTENTIOMETRIC METHOD FOR DETERMINATION OF CARBON
2.1. The essence of the method
The method is based on the combustion of a test sample in flowing oxygen in a tube furnace at 1250−1350 °C with subsequent absorption of the formed carbon dioxide electrolyte solution.
Carbon dioxide, absorbed in the electrolyte changes the pH of the solution and thus changes the potential of the electrodes, then electrolyte titrated with a solution of hydroxide of barium to the original pH (9,7−10).
(Changed edition, Rev. N 1).
2.2. Apparatus, reagents and solutions
Setup for determination of carbon, shown in the drawing, consists of a cylinder 1 with a pressure reducing valve and oxygen (GOST 5583); flowmeter type RS-ZL or RM- 2; flask 3 with Astarita; startup shutter 4; dogtramadol furnace 5 with sheltowee heaters providing heat to (1300±20) °C; dust filter 6; a capillary choke 7; flask 8filled with granular manganese dioxide; electrolytic cell 9; the agitator 10; the electrode system 11; dropper 12 to enter into the cell volume of the titrant used; electric motor 13; burette 14 with a capacity of 10−25 cm; magnetic valve 15; pH meter 16of the type pH 340 or pH 121; normal item 17; block of automatic titration 18(BAT 15, BAT-12ЛМ).
Note. Instead of a burette 14, the magnetic valve 15 can be to use the automatic burette dispenser B-701. Electrolytic cell 9 with a capacity of 200 cmcan be replaced by a vessel with a porous filter N 2 or 3 with a capacity of 100 cm
.
Allowed to use the analyzer to ensure accuracy not lower than specified in the standard.
Normal element connected in case of use of pH meter pH-340 BAHT 12ЛМ.
Manganese sulfate according to GOST 435.
Ammonia according to GOST 3760.
Granulated manganese dioxide and 200 g of manganese sulfate is dissolved in 2500 cmof hot water, then in the solution add 25 cm
of ammonia; add 1000 cm
to 22.5% strength solution naternicola ammonium and the mixture boiled for 10 min. while boiling, add ammonia to alkaline reaction, then the solution to stand until complete precipitation of manganese dioxide. The precipitate was filtered off, washed and dried at 110 °C.
Askari.
The lime soda.
Ammonium neccersarily according to GOST 20478, 22,5% solution.
Pumps porcelain LS-2, LS-4 according to GOST 9147.
Tube refractory mullite inner diameter of 20−21 mm.
Potassium chloride according to GOST 4234, saturated solution.
Barium chloride according to GOST 4108, electrolyte solution: 10 g of barium chloride dissolved in 1000 cmof distilled water and to the obtained solution poured 10 cm
of ethanol.
Barium hydroxide according to GOST 4107, a saturated solution of the hydroxide of barium is dissolved in distilled water (pre-boiled for 2 h and cooled to room temperature). The resulting solution is diluted 30 times. The solution is stored in bottles fitted with tubes with soda lime.
The technical rectified ethyl alcohol according to GOST 18300.
Standard samples of category, GEO, CCA, SOP, in which the content of component is not different from that analyzed more than two times.
(Changed edition, Rev. N 1)
.
2.3. Preparation for assay
To the output of the pH meter is connected to the block automatic titration series using normal element. Set up a pH meter and an automatic titration unit according to the attached instructions to these devices.
The electrode system set up against the buffer solution of 9.18 pH-9,22 (fixanal 0.01 M solution of potassium tetraborate).
The porcelain boat was calcined in flowing oxygen at 1280 °C for 3 min.
Electrolytic cell filled with electrolyte 200 cm, and in the case of a cell with a porous partition 100 cm
.
Set the oxygen flow rate is 700 cmin 1 min. Include the BAT in the titration and the pH adjusted to 10.
Burning 3−4 sample standard sample, set the caption of the hydroxide of barium.
Samples of tungsten acid is calcined for 4 h at (650±10) °C to tungsten trioxide.
Samples of ammonium paratungstate is transferred to the tungsten oxide by calcination (650±10) °C for 1.5 h.
Tungsten dioxide is burned in a current of oxygen without pre-treatment.
Samples of metal tungsten is cleaned from possible contamination by washing with 5−10 cmof alcohol.
2.4. Analysis
Depending on the mass fraction of carbon in the sample take a different sample in accordance with table.1.
Burnt the boat with a weighed test portion is placed in a tube for burning, close the shutter and include a block of automatic titration for titration.
The end of the analysis of the fixed block automatic titration burette and the measured amount of a solution of hydroxide of barium, used for titration.
Burning a standard sample for determining the titer done after every fifth sample analyzed.
Table 1
| Mass fraction of carbon, % |
The mass of charge, g |
| From 0.0005 to 0.001 | Of 2.00 |
| SV. Of 0.001 «to 0.005 | Of 1.00 |
| «Of 0.005» to 0.05 | 0,50 |
| «0,05» 0,5 |
0,25 |
2.5. Processing of the results
2.5.1. Mass fraction of carbon () in percent is calculated by the formula
where — volume of the solution of hydroxide of barium, used for titration of the test solution, cm
;
the volume of the solution of hydroxide of barium, used for titration of the solution in a control experiment, cm
;
the titer of a solution of hydroxide of barium, expressed in g/cm
carbon;
— weight of charge, g
.
2.5.2. Allowable absolute differences of the results of three parallel measurements at a confidence level =0.95 does not exceed the values specified in table.2.
Table 2
| Mass fraction of carbon, % |
The absolute allowable difference, % |
| From 0.0005 to 0.001 |
0,0003 |
| SV. Of 0.001 «to 0.003 to |
0,0004 |
| «Of 0.003» to 0.01 |
0,001 |
| «Is 0.01» to 0.03 |
0,002 |
| «0,03» 0,1 |
0,004 |
| «0,1» 0,3 |
0,015 |
| «0,3» 0,5 |
0,025 |
(Changed edition, Rev. N 1).
3. COULOMETRIC METHOD FOR DETERMINING CARBON
3.1. The essence of the method
The method is based on the combustion of a test sample in flowing oxygen in a tube furnace at 1200−1250 °C with subsequent absorption of the formed carbon dioxide electrolyte solution.
Then the electrolyte electrolyzed to restore the original pH, and the amount of consumed electricity in the electrolysis process to measure the carbon content.
3.2. Equipment, reagents, solutions
Coulometric analyzer an-7560 or any other type for that range, determine carbon content.
Resistance furnace providing heating up to (1300±20) °C.
Cylinder with reducing valve with oxygen according to GOST 5583.
Pumps porcelain LS-2 and LS-4 according to GOST 9147.
Tube refractory mullite inner diameter of 20−21 mm.
The technical rectified ethyl alcohol according to GOST 18300.
Standard samples of category, GEO, CCA, SOP, in which the content of component is not different from that analyzed more than two times.
(Changed edition, Rev. N 1).
3.3. Preparation for assay
The porcelain boat was calcined in flowing oxygen at 1280 °C for 3 min.
Include the analyzer to the network and configured. The analyzer is calibrated by standard samples.
Samples of tungsten acid is dehydrated and calcined for 4 h at (650±10) °C to tungsten trioxide.
Samples of ammonium paratungstate is transferred to the tungsten oxide by calcination (650±10) °C for 1.5 h.
Tungsten dioxide is burned in a current of oxygen without pre-treatment.
Samples of metal tungsten is cleaned from possible contamination by washing with 5−10 cmof alcohol.
3.4. Analysis
Depending on the mass fraction of carbon in the sample take a different sample in accordance with table.1.
A boat with prepared breakdown is placed in a tube for burning, close the shutter and turn on the device for titration.
(Changed edition, Rev. N 1).
3.5. Processing of the results
3.5.1. Mass fraction of carbon in percent less carbon content found in the control experiment corresponds to the indication of the digital display device.
3.5.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level =0.95 does not exceed the values specified in table.2.
(Changed edition, Rev. N 1).
3.5.3. The method used in the disagreement in assessing the quality of tungsten.
