GOST 26473.7-85
GOST 26473.7−85 Alloys and alloys based on vanadium. Method for the determination of arsenic (Change No. 1)
GOST 26473.7−85
Group B59
STATE STANDARD OF THE USSR
ALLOYS AND MASTER ALLOYS BASED ON VANADIUM
Method for the determination of arsenic
Vanadium base alloys and alloying elements. Method for determination of arsenic
AXTU 1709
Valid from 01.07.86
to 01.07.91*
_______________________________
* Expiration removed
by the decree of Gosstandart of the USSR from
(IUS N 8, 1991). — Note the manufacturer’s database.
DEVELOPED by the Ministry of nonferrous metallurgy of the USSR
PERFORMERS
Yu. A. Karpov, E. G. Nembrini, V. G., Miscreants, V. V. Nedler, V. M. Mikhailov, L. G. Agapova, G. N. Andrianov, A. V. Antonov, V. D. Dozen, M. A. Desyatkova, T. I. Kirillova, L. I. Kirsanov, I. E. Korepin, V. A. Orlova, N. Rasnitsyn, N. Suvorova, N. L. Tomasev, M. W. Schmidt, L. N. Filimonov
INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
Member Of The Board Of A. P. Snurnikov
APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on standards of 25 March 1985, N 751
The Change N 1, approved and put into effect by the Decree of the USSR State Committee on management of quality and standards from
Change No. 1 made by the manufacturer of the database in the text IUS N 2, 1990
This standard sets the photometric method for the determination of arsenic (from 1·10to 1·10
%) in alloys and master alloys based on vanadium, the contents of related components which are shown in table.1.
Table 1
| The accompanying component |
Mass fraction, %, not more |
| Aluminium |
50 |
| Tungsten |
8 |
| Iron |
5 |
| Silicon |
1 |
| Manganese |
2,5 |
| Molybdenum |
25 |
| Niobium |
25 |
| Titan |
25 |
| Chrome |
40 |
| Cubic Zirconia |
3 |
The method is based on extraction separation of arsenic from the substrate in the form of Awith subsequent re-extraction with water, the formation in the aqueous phase of the reduced form of michalopolous heteroalicyclic and fotomaterialy the color of the solution.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 26473.0−85.
2. APPARATUS, REAGENTS AND SOLUTIONS
Type photoelectrocolorimeter FEK-56.
Analytical scale.
Libra technical.
Tile electric.
Bath water.
Stopwatch.
Separating funnel with a capacity of 50 and 100 cm.
Volumetric flasks with a capacity of 25, 50 and 100 cm.
Pipettes with a capacity of 1 and 5 cmwith divisions.
Pipettes with a capacity of 5 and 10 cmwith no divisions.
Microburette with a capacity of 5 cmwith a scale division of 0.02 cm
.
Measuring beakers with a capacity of 25 and 100 cm.
Crucibles of glassy carbon brand SU-2000 with a capacity of 50 cm.
Watch-glasses with a diameter of 40 mm.
Hydrochloric acid according to GOST 14261−77.
Nitric acid according to GOST 11125−84 and diluted 1:1.
The technical rectified ethyl alcohol GOST 18300−87.
Carbon tetrachloride, OS.h.
Potassium iodide, OS. h, a saturated solution.
Potassium permanganate according to GOST 20490−75, solution concentration 100 g/DM.
Ammonium molybdate according to GOST 3765−78, solution concentration of 50 g/DM.
Potassium armanavicius, solution concentration 3 g/DM.
Ascorbic acid food, solution concentration of 0.1 mol/DM: 1.76 g of ascorbic acid dissolved in 100 cm
of water. A mixture of reagent A (prepared before use): merge 12 cm
of hydrochloric acid, 15 cm
of ammonium molybdate, 12 cm
solution Armenonville potassium and 15 cm
of ascorbic acid solution, mix and dilute with water to 100 cm
.
Michalkovsky disodium sodium, NaNo
·12H
O.
Standard solution of arsenic (spare) containing 1 mg/cmof arsenic (V): 0,420 g twosemester 12-water Myslakowice sodium dissolved in water, transferred to a volumetric flask with a capacity of 100 cm
, adjusted to the mark with water, mix.
Solution of arsenic (work) containing 0.01 mg/cm(10 µ g/cm
) arsenic (V), prepared on the day of use by dilution of a backup solution with water to 100 times.
(Changed edition, Rev. N 1).
3. PREPARATION FOR ASSAY
A portion of the sample weighing 0.5 g (for the mass concentration of arsenic from 1·10to 1·10
%) or 0.1 g (for the mass concentration of arsenic from 1·10
to 1·10
%) placed in a glassy carbon crucible and dissolved with gentle heating in 10 cm
of nitric acid, diluted 1:1, 3 cm
hydrofluoric acid (the dissolution of master alloys containing titanium, chromium, niobium, tungsten and zirconium) with 3 drops of a solution of potassium permanganate. The resulting solution is evaporated in a water bath to dryness.
The residue is dissolved under heating in a mixture of 7 cmof concentrated hydrochloric acid and 5 cm
of ethyl alcohol, a Cup covered with watch glass. The solution is heated to obtain a bright blue color (in the presence of a chromium solution color bright green), transferred to a volumetric flask with a capacity of 50 cm
, flow 15 cm
of concentrated hydrochloric acid and adjusted to the mark with water (stock solution), which is used for the determination of phosphorus GOST 26473.9−85.
4. ANALYSIS
4.1. In a separating funnel with a capacity of 100 cmpipetted aliquot part of the solution (5 cm
) containing 0.5−10 µg of arsenic, poured 10 cm
of carbon tetrachloride, a 3 cm
saturated solution of potassium iodide, 40 cm
of concentrated hydrochloric acid and shaken for 2 min. Organic phase (bottom layer) is transferred to a separatory funnel with a capacity of 50 cm
, pour 0.5 cm
of a saturated solution of potassium iodide, and 9.5 cm
of concentrated hydrochloric acid, and shake the funnel for 5 s.
The organic phase (bottom layer) is transferred to a separatory funnel with a capacity of 50 cmand extravert arsenic 10 cm
of water for 1 min.
Reextract (top layer) was transferred into a measuring flask with a capacity of 25 cmand add dropwise a solution of potassium permanganate until a stable bright crimson coloring. After 5 min, a solution of ascorbic acid to the bleaching solution and 5 cm
of the mixture of reagents A. the Volume of the solution was adjusted to the mark with water and after 30−50 min, measure the optical density of the solution on the photoelectrocolorimeter using a filter with maximum transmittance at a wavelength of 630 nm and cuvette thickness of the light absorbing layer 50 mm relative to the solution in the reference experiment.
Control the experience on the content of arsenic in the reagents carry through all stages of analysis simultaneously with analysis of a series of samples. The value of the optical density of the solution in the reference experiment, measured relative to the water should not exceed 0.05, otherwise change the reagents.
The mass of arsenic found by the calibration gra
fico.
4.2. Construction of calibration curve
In a separating funnel with a capacity of 100 cmpoured from microburette 0,05; 0,1; 0,5; 1,0; 1,5 and 2,0 cm
working standard solution of arsenic (V), which corresponds to 0,5; 1; 5; 10; 15 and 20 micrograms of arsenic. Pour 10 cm
of carbon tetrachloride and then do as described in claim 4.1, conducting a measurement of optical density in relation to the simultaneously cooked «zero» solution containing all reagents, except standard solution of arsenic.
On the found values of optical density and corresponding mass of arsenic build the calibration graph.
5. PROCESSING OF THE RESULTS
5.1. Mass fraction of arsenic () in percent is calculated by the formula
where is the mass of arsenic, was found in the calibration schedule, mcg;
— capacity volumetric flasks, cm
;
— aliquotes volume of the solution taken for the determining, cm
;
— the weight of the portion of the sample,
5.2. The values of permissible differences are listed in table.2.
Table 2
| Mass fraction of arsenic, % |
Allowable difference, % |
10·10 |
5·10 |
50·10 |
1,5·10 |
10·10 |
2·10 |
5·10 |
1·10 |
10·10 |
2·10 |
(Changed edition, Rev. N 1).
