GOST 14338.1-82
GOST 14338.1−82 Molybdenum. Methods for determination of carbon (Change No. 1)
GOST 14338.1−82
Group B59
STATE STANDARD OF THE USSR
MOLYBDENUM
Methods for determination of carbon
Molybdenum. Methods for determination of carbon
AXTU 1709
Valid from 01.01.84
before 01.01.92*
_______________________________
* Expiration removed
by the decree of Gosstandart of the USSR
from
— Note the manufacturer’s database.
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
PERFORMERS
V. I. Veprintsev, S. N. Suvorova, Y. A. Abramov, L. V. Mikhailov, V. V., Sultanian
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. REPLACE GOST 14338.1−74
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
The number of the paragraph, subparagraph |
| 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, 3.2 |
| GOST 9147−80 | 2.2, 3.2 |
| GOST 10262−73 | 2.2, 3.2 |
| GOST 14338.0−82 | 1.1 |
| GOST 18300−87 | 2.2, 3.2 |
| GOST 20478−75 | 2.2 |
5. Validity extended till
6. REPRINT (August 1988) with amendment No. 1, approved in April 1988 (I & C 7−88)
This standard specifies the potentiometric and coulometric (with the mass fraction of carbon from 0.0005 to 0.5%) methods for determination of carbon in the metal molybdenum, molybdenum anhydride, ammonium molybdate.
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 14338.0−82.
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 1200−1300 °C, followed by absorption of the formed carbon dioxide electrolyte solution.
Carbon dioxide, absorbed in the electrolyte changes the pH of the solution and thereby changes the electrode potential. The electrolyte is titrated with a solution of hydroxide of barium to the original pH (9,7−10).
2.2. Equipment, reagents, solutions
Setup for determination of carbon, shown in the drawing, consists of a cylinder 1 with a pressure reducing valve and oxygen (GOST 5583−78); flowmeter 2 type RS-3, or RM-A; flask 3 with Astarita; startup shutter 4; dogtramadol furnace 5 with silicafume heaters that provide heating to 1300±20 °C; dust filter 6; a capillary choke 7; flask 8filled with granular manganese dioxide; electrolytic cell 9, which put 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 16 of the type pH 340 or pH 121; normal element 17 and the 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 No. 2 or No. 3 with a capacity of 100 cm
.
Normal element connected in case of use of pH meter pH-340 BAHT 12ЛМ.
Allowed to use the analyzer to ensure accuracy not lower than specified in the standard.
Ammonia according to GOST 3760−79.
Askari.
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. Then 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 with water and dried at 110 °C.
Ammonium neccersarily according to GOST 20478−75, 22,5% solution.
Manganese sulfate according to GOST 435−77.
The lime soda.
Pumps porcelain LS-2, LS-4 according to GOST 9147−80.
Refractory mullite tube with an inner diameter of 20−21 mm.
Potassium chloride according to GOST 4234−77, saturated solution.
Barium chloride according to GOST 4108−72, 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 4107−78, 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.
Rectified ethyl alcohol GOST 18300−87.
Zinc oxide according to GOST 10262−73.
Standard samples of categories of GEO, CCA, SOP, which certified the content of a component is not different from that analyzed more than two times
.
2.1; 2.2. (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).
Porcelain boats and the zinc oxide is calcined in flowing oxygen at 1280 °C for 3 min.
Electrolytic cell filled with electrolyte 200 cm(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 the ammonium molybdate is calcined in a muffle furnace at 400−450 °C to complete oxidation.
Samples of molybdenum metal is cleaned of possible contamination by washing with 5−10 cmof alcohol.
2.4. Analysis
Depending on the mass fraction of carbon in the different samples take the sample in accordance with table.1.
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 |
The sample is placed in a boat calcined and thoroughly mixed with the zinc oxide in a ratio of 1:2.
A boat with prepared breakdown is placed in a tube for burning, close the shutter and block automatic titration include the handle «titration». The end of the analyze record block automatic titration burette and count the number of solution of hydrate of an oxide of barium, used for titration.
Burning a standard sample for determining the titer done after every fifth sample analyzed.
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 solution of the sample, 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 sample, g
.
2.5.2. Allowable absolute differences of the results of three parallel measurements at a confidence probability of 0.95 does not exceed the values given in table.2.
Table 2
| Mass fraction of carbon, % | Allowable absolute differences, % |
| To from 0,0005 0,0010 incl. | 0,0003 |
| SV. 0,0010 «0,0030 « | 0,0004 |
| «0,0030» 0,0060 « | 0,0005 |
| «0,006» 0,010 « | 0,001 |
| «0,010» 0,030 « | 0,002 |
| «0,030» 0,050 « | 0,003 |
| «0,050» 0,100 « | 0,006 |
| «0,100» 0,300 « | 0,012 |
| «0,300» 0,500 « | 0,015 |
(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 forming carbon dioxide with a solution of electrolyte, 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 to a temperature (1300±20) °C.
Cylinder with reducing valve with oxygen according to GOST 5583−78.
Pumps porcelain LS-2, LS-4 according to GOST 9147−80.
Tube refractory mullite inner diameter of 20−21 mm.
Rectified ethyl alcohol GOST 18300−87.
Zinc oxide according to GOST 10262−73.
The standard sample WITH-126. Can use standard sample category of the CCA and SOP, which certified the content of a component is not different from that analyzed more than two times.
(Changed edition, Rev. N 1).
3.3. Preparation for assay
Porcelain boats and the zinc oxide is 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 the ammonium molybdate is calcined in a muffle furnace at 400−450 °C to complete oxidation.
Samples of molybdenum metal is cleaned of possible contamination by washing with 5−10 cmof alcohol.
3.4. Analysis
Depending on the mass fraction of carbon in the samples take the sample in accordance with table.1.
The sample is placed in a boat calcined and thoroughly mixed with the zinc oxide in a ratio of 1:2.
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 minus the mass fraction of carbon found in a 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 probability of 0.95 does not exceed the values given in table.2.
(Changed edition, Rev. N 1).
3.5.3. The method used in the disagreement in assessing the quality of molybdenum.
