GOST 25278.5-82
GOST 25278.5−82 Alloys and alloys of rare metals. Method for the determination of cobalt (with Change No. 1)
GOST 25278.5−82
Group B59
STATE STANDARD OF THE USSR
ALLOYS AND ALLOYS OF RARE METALS
Method for the determination of cobalt
Alloys and foundry alloys of rare metals. Method for determination of cobalt
AXTU 1709
Valid from 01.07.83
to 01.07.93*
_______________________________
* Expiration removed
according to the Protocol of the Intergovernmental Council
for standardization, Metrology and certification
(IUS N 2, 1993). — Note the manufacturer’s database.
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
PERFORMERS
Yu. A. Karpov, E. G. Nembrini, V. G., Miscreants, G. N. Andrianov, E. S. Danilin, M. A. Desyatkova L. I. Kirsanova, T. M. Malyutina, Y. F. Markov, V. M. Mikhailov, L. A. Nikitina, L. G. Obruchkova, N. Rasnitsyn, N. Suvorova, L. N. Filimonov
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. The period of examination — 1993
The frequency of inspection — 5 years
4. INTRODUCED FOR THE FIRST TIME
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
The designation of the reference document referenced |
Section number, paragraph |
GOST 3118−77 |
Sec. 2 |
GOST 3760−79 |
Sec. 2 |
GOST 4233−77 |
Sec. 2 |
GOST 4461−77 |
Sec. 2 |
GOST 4463−76 |
Sec. 2 |
GOST 10398−76 |
Sec. 2 |
GOST 10652−73 |
Sec. 2 |
GOST 25278.8−82 |
Sec. 3 |
GOST 26473.0−85 |
1.1 |
6. Validity extended until
7. REPRINT (November 1988) with amendment No. 1, approved in October 1987 (ICS 1−88).
This standard specifies the chelatometric method for the determination of cobalt (60 to 65%) in binary alloys, samarium-cobalt.
The method is based on complexometric direct titration of cobalt in ammoniacal medium at pH 8−9 with indicator murexide.
Samarium fluoride mask.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis and security requirements — according to GOST 26473.0−85.
(Changed edition, Rev. N 1).
2. APPARATUS, REAGENTS AND SOLUTIONS
Tile electric.
Analytical scale.
Libra technical.
Burettes capacity 10 cm.
Pipettes without dividing by 5 cm.
Conical flasks with a capacity of 250 cm.
Nitric acid GOST 4461−77 diluted 1:1.
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Ammonia water according to GOST 3760−79 diluted 1:1.
Sodium fluoride according to GOST 4463−76, a solution of 40 g/DM.
Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid, 2-water (Trilon B) according to GOST 10652−73, solution 0,025 mol/l; prepared as follows: 9.3 g Trilon B dissolved in water with heating (if the solution is turbid, it is filtered), transferred to a volumetric flask with a capacity of 1 DM, is cooled and adjusted to the mark with water.
The ratio of the molarity of the solution Trilon B is determined by solution of salt of zinc (GOST 10398−76).
Murexide.
Sodium chloride according to GOST 4233−77.
Mix indicator: 0.1 g of murexide mixed well in a mortar with 10 g of sodium chloride.
(Changed edition, Rev. N 1).
3. ANALYSIS
A portion of the sample weighing 0.5 g 1 g* placed in a conical flask with a capacity of 250 cm, 10−15 cm pouredhydrochloric acid and 10−15 cmof nitric acid, wash the walls of the bulb 10−15 cmof water and heated until complete dissolution of the sample. The solution was cooled, transferred to a volumetric flask with a capacity of 250 cm, was adjusted to the mark with water and mix (solution can be used to determine Samaria according to GOST 25278.8−82).
_________________
* The text matches the original. — Note the manufacturer’s database.
In a conical flask with a capacity of 250 cmtaken 10 cmof the resulting solution, diluted to 100 cmwith water, add 10 cmof a solution of sodium fluoride, mix well. Add 0.1−0.2 g indicator mixture, poured dropwise a solution of ammonia until yellow color of the solution and titrated cobalt with a solution of Trilon B before transition of colouring from yellow to crimson. If the ammonia is added the color of the solution again becomes yellow, the titration is continued until until after adding the ammonia the crimson color of the solution will not change.
(Changed edition, Rev. N 1).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of cobalt () in percent is calculated by the formula
,
where — volume of solution Trilon B, used for titration, cm;
0,001473 — the concentration of the solution Trilon B on the cobalt, g/sm;
— the ratio of the molarity of the solution Trilon B;
— capacity volumetric flasks, cm;
— aliquotes volume of the solution taken for titration, cm;
— the weight of the portion of the sample,
4.2. Discrepancies between the results of two parallel determinations and the results of the two tests should not exceed 0.8%.
4.1, 4.2. (Changed edition, Rev. N 1).