GOST 26473.2-85
GOST 26473.2−85 Alloys and alloys based on vanadium. Methods for determination of tungsten (Change No. 1)
GOST 26473.2−85
Group B59
STATE STANDARD OF THE USSR
ALLOYS AND MASTER ALLOYS BASED ON VANADIUM
Methods for determination of tungsten
Vanadium base alloys and alloying elements. Methods for determination of tungsten
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, 752
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 specifies the extraction-photometric and x-ray fluorescence methods for determination of tungsten (6 to 8%) in binary alloys of the vanadium and tungsten.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 26473.0−85.
2. EXTRACTION-PHOTOMETRICALLY METHOD FOR THE DETERMINATION OF TUNGSTEN
The method is based on formation of colored dithiolate of tungsten in hydrochloric acid medium, extraction of the complex compound of carbon tetrachloride and fotomaterialy coloring extract. Vanadium definition does not interfere.
2.1. Apparatus, reagents and solutions
Type photoelectrocolorimeter FEK-56.
Analytical scale.
Libra technical.
Tile electric.
Muffle furnace with thermostat providing temperatures up to 1000 °C.
Bath water.
The quartz crucibles high capacity of 40 cm.
Volumetric flasks with a capacity of 25, 50, 100, 250 and 1000 cm.
Pipettes with a capacity of 10 cmwith no divisions.
Pipette plastic.
Microburette with a capacity of 5 cmwith a scale division of 0.02 cm
.
Measuring beakers with a capacity of 25, 100 cm.
Sand timer for 2 minutes, or stopwatch.
Separating funnel with a capacity of 50 cm.
Obestochennye paper filter «white ribbon», a diameter of 70 mm.
Hydrochloric acid by the GOST 3118−77.
Sulfuric acid GOST 4204−77 and diluted 1:4.
Hydrofluoric acid according to GOST 10484−78.
Potassium preservatory according to GOST 7172−76.
Sodium hydroxide according to GOST 4328−77, solution concentration of 80 g/DM.
Ammonium oxalate according to GOST 5712−78, solution with concentration of 40 g/DM.
Carbon tetrachloride according to GOST 20288−74.
The technical rectified ethyl alcohol GOST 18300−87.
Zinc-dithiol (3,4-dimercaptotoluene zinc salt) solution of concentration 10 g/DM: 1 g of the reagent moistened with 10−12 cm
of ethyl alcohol, poured 100 cm
of sodium hydroxide solution, stirred. The solution is prepared the day of use.
Titanium sulfate, solution concentration of 10 g/DM: 1 g of titanium metal with a basic substance content not less than 99.5% was dissolved with heating in 100 cm
of sulphuric acid (1:4) with the addition of 1−2 cm
hydrofluoric acid.
Mixture for recovery of tungsten: 60 cmof titanium sulfate solution is diluted with 150 cm
of hydrochloric acid, mix. The mixture is prepared the day of use.
Hydrogen peroxide according to GOST 10929−76.
Ammonia water according to GOST 3760−79.
Tungsten metal containing at least 99.9% of the tungsten in the form of a powder or fine shavings.
Tungsten (VI) oxide.
Standard solution tungsten (spare) containing 0.1 mg/cm(100 g/cm
) tungsten, prepare one of the following methods.
The first method. 0.1 g of metal tungsten is placed in a beaker with a capacity of 200 cm, flow of 5−10 cm
of water, 20−25 cm
of hydrogen peroxide and heated to dissolve the sample, stirring occasionally. After reconstitution, gently, drop by drop, add 2 cm
of ammonia and again heated to a decolorizing solution. The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM
, adjusted to the mark with water.
The second method. 0,1261 g of tungsten oxide, calcined to constant weight at 600−700 °C, were placed in a glass with a capacity of 100 cmand dissolved in 20−25 cm
of sodium hydroxide solution, transferred to a volumetric flask with a capacity of 1 DM
, pour 100 cm
of sodium hydroxide solution, adjusted to the mark with water.
A solution of tungsten (work) containing 0.01 mg/cm(10 µ g/cm
) of tungsten, is prepared by diluting a backup solution with water in 10 times. The solution is prepared the day of use.
(Modified …
tion, Rev. N 1).
2.2. Analysis
2.2.1. A portion of the sample weighing 0.1 g was placed in a quartz crucible, add 4−6 grams of potassium peacemaking, 2−3 drops of concentrated sulphuric acid. Place the crucible on an electric stove and melt preservatory potassium before the appearance of sulphuric acid fumes. Then cover the crucible with a lid, transfer the crucible to a muffle furnace and conduct alloying at 700−800 °C to obtain a homogeneous melt. Fusion are very carefully first with an open muffle, and then gradually moving the crucible into the hot zone of the muffle. If fusion was not completely, the melt is cooled, add a few drops of concentrated sulfuric acid and re-melted to obtain a homogeneous melt.
The smelt is cooled and dissolved by heating in 30 cmof a solution of ammonium oxalate, the cooled solution was transferred to volumetric flask with a capacity of 250 cm
, was adjusted to the mark with water.
The resulting solution was diluted again: take 10 cmof solution in a volumetric flask with a capacity of 100 cm
and adjusted to the mark with water.
For the determination of tungsten in conical flask with a capacity of 50 cmpipetted 10 cm
of a solution containing 20−40 µg of tungsten, poured 10 cm
of the replacement mixture and heated in a boiling water bath for 10−15 min, pour 5 cm
of solution zinc dithiol and continue heating on a boiling water bath for 10−15 min.
The cooled solution was transferred to a separatory funnel with a capacity of 50 cm. The flask is rinsed with two portions of 5 cm
of carbon tetrachloride, which are also transferred to a separatory funnel. Separating funnel is stoppered and perform the extraction dithiolate tungsten, intensely shaking the funnel for 2 min. After the separation of the organic phase (lower layer) is drained into a dry volumetric flask with a capacity of 25 cm
. Dithiolate extraction of tungsten is carried out several times in portions of 5−7 cm
of carbon tetrachloride to obtain a colorless organic layer. The resulting extract is collected in a volumetric flask with a capacity of 25 cm
, adjusted to the mark with carbon tetrachloride.
Part of the extract was filtered through a dry paper filter into a dry cuvette with the thickness of the light absorbing layer 20 mm and measure the optical density of the extract on the photoelectrocolorimeter using a filter with maximum transmittance at ~607 nm relative to carbon tetrachloride, covering the cuvettes with lids.
A lot of tungsten find for the calibration g
Rafik.
2.2.2. Construction of calibration curve
In a volumetric flask with a capacity of 50 cmis injected from microburette 2,0; 2,5; 3,0; 3,5 and 4,0 cm
working standard solution of tungsten, corresponding to a 20, 25, 30, 35 and 40 ág of tungsten. Go to 10 cm
water, 10 cm
replacement mixture and then the determination is carried out according to claim
On the found values of optical density and corresponding mass of tungsten to build a calibration curve.
2.3. Processing of the results
2.3.1. Mass fraction of tungsten () in percent is calculated by the formula
where is the mass of tungsten was found in the calibration schedule, mcg;
— the volume of volumetric flasks at the first dilution, cm
;
— volume of the volumetric flask for the second dilution, cm
;
— aliquotes volume of the solution taken for dilution, cm
;
— aliquotes volume of the solution taken for the determining, cm
;
— the weight of the portion of the sample,
G.
2.3.2. The values of permissible differences when the mass fraction of tungsten from 6 to 8% shall not exceed 0.5%.
(Changed edition, Rev. N 1).
3. X-RAY FLUORESCENCE METHOD FOR THE DETERMINATION OF TUNGSTEN
The method is based on placing the sample in solution, excitation of the atoms of the sample flow of the primary x-ray quanta and the determination of the mass fraction of tungsten in the measured intensity of the characteristic fluorescence emission lines of tungsten using a calibration chart, the intensity of radiation from a mass fraction of tungsten.
3.1. Apparatus, reagents and solutions
Fluorescent x-ray quantometer type FRK-10 (x-ray tube bkhv-7 with a gold mirror of the anode) or similar device, equipped with a special cuvette, allowing to work with the solutions.
Cuvette for x-ray fluorescence analysis of solutions (see drawing) consists of a metal (steel GOST 5632−72) a cylindrical body with a screw-down metal lid with a gasket made of acid-resistant rubber (GOST 7338−77*). Inside the cylindrical body must be tightly inserted Teflon (GOST 10007−80) a cylindrical liner, the lower part of which is made in the form of two concentrically located relative to each other and vertical to the axis of the liner conical protrusions with depth between them to ensure a tight nozzle liner to the body of the cell.
______________
* On the territory of the Russian Federation GOST 7338−90. — Note the manufacturer’s database.
1 — cylindrical metal housing; 2 — cover (nut); 3 — a lining of acid-resistant rubber; 4 — Teflon liner; 5 — tube fluoropolymer; 6 — connection; 7 — a metal flange; 8 — conical projections; 9 — polymer film
Between the inner portion of the housing and the base of the PTFE liner using tapered protrusions attached polymer (polyethylene terephthalate according to GOST 24234−80) film with a thickness of 20 µm. The tension of the film and its fixing are achieved by full pressing the PTFE liner to the base case clamping metal (GOST 5632−72) flange with the screw connection.
In the lower part ftoroplastov liner, made in the form of a truncated cone, placed the analyzed solution (working volume of the cell is 6 cm).
In the upper part (cylinder) PTFE fluoropolymer liner placed the cork (float), made in the form of a cylinder with hemispherical (oval) base and a ring-shaped ledge, loosely adjacent to the side walls of the liner, close the housing cover with seal, spinning the cover until it stops. While the oval base Teflon tube immersed in the solution, displacing the working volume of the cell is air and part of the solution, and the annular protrusion of the tube pressed tightly to the inner ledge Teflon liner and seals the working volume of the cuvette.
Analytical scale.
Libra technical.
Tile electric.
Muffle furnace with thermostat providing temperatures up to 900 °C.
The infrared lamp of the type ikz-500 with voltage regulator type RNO-250−05.
The chemical glasses with a capacity of 100, 200, 300 cm.
Volumetric flasks with a capacity of 50, 200 cm.
The quartz Cup with a capacity of 30 cm.
Platinum crucibles with a capacity of 30 cm.
Pipettes with a capacity of 10 cmwith no divisions.
Burettes capacity 10 cmwith a scale division of 0.02 cm
.
Measuring beakers with a capacity of 25 and 50 cm.
Desiccator with calcium chloride.
Sulfuric acid according to GOST 4204−77.
Hydrofluoric acid according to GOST 10484−78.
Nitric acid GOST 4461−77 and diluted 1:1, 1:5.
Orthophosphoric acid according to GOST 6552−80, diluted 1:1.
The mixture of acids to dissolve: mix equal volumes of nitric and phosphoric acids, dilute 1:1.
Hydrogen peroxide according to GOST 10929−76.
Sodium hydroxide according to GOST 4328−77.
The filter paper obestochennye red ribbon or white ribbon.
The platinum crucibles.
Funnels, glass, conical with a diameter of 30 mm.
Vanadium metal containing not more than 0.01% of tungsten.
Tungsten metal containing at least 99.9% of the tungsten in the form of a powder or fine shavings.
Tungsten (VI) oxide.
A standard solution of tungsten containing 5 mg/cmtungsten, prepare one of the following methods.
The first method. 1 g of metallic tungsten is placed in a beaker with a capacity of 200 cm, flow of 5−10 cm
of water, 20−25 cm
of hydrogen peroxide and heat until dissolved, stirring occasionally. Once dissolved, continue boiling for 10−15 minutes for the destruction of hydrogen peroxide. The cooled solution was transferred to volumetric flask with a capacity of 200 cm
and was adjusted to the mark with water.
Accurate mass concentration of tungsten set by gravimetric method. To do this in a quartz Cup, pre-calcined in a muffle furnace to constant weight at a temperature of 450−500 °C, pipetted 20 cmstandard solution tungsten. The solution is evaporated gently under a heat lamp to dryness, put a Cup of sediment in a muffle furnace and calcined for 30 minutes at 800−900 °C, cooled in a desiccator, weigh. The calcination and weighing is repeated until obtaining constant weight.
The mass concentration of a standard solution tungsten (), expressed in mg/cm
, calculated by the formula
where is the mass of calcined sludge, mg;
0,7930 — the ratio of tungsten oxide to tungsten.
The second method. 1,261 g of tungsten oxide, calcined to constant weight at 600−700 °C, were placed in a glass with a capacity of 250−300 cm, pour 100−150 cm
of water, add 20 g of sodium hydroxide and slightly heated to dissolve the sample. The solution was cooled, transferred to a volumetric flask with a capacity of 200 cm
, adjusted to the mark with water.
Accurate mass concentration of tungsten set by gravimetric method. To do this in a glass with a capacity of 150−200 cmpipetted 20 cm
standard solution tungsten, pour 15 cm
of concentrated nitric acid and evaporate the solution to a volume of 5−10 cm
. Then pour 100 cm
of boiling water, boil for a few minutes, add a little maseribane paper, the precipitate filtered off on ashless filter «red» or «white ribbon», which is placed in a glass funnel, washing the residue with warm nitric acid diluted 1:5.
The filter with precipitate was placed in a weighed platinum crucible, dried, incinerated and calcined in a muffle furnace to constant weight at 800−900 °C.
Suspended sediment moistened with 2−3 drops of water poured 5−6 drops of concentrated sulfuric acid and 2 cmhydrofluoric acid. The crucible is placed on a hot plate with a closed spiral and carefully evaporated until the termination of allocation of steams of sulfuric acid. The dry residue is calcined in a muffle furnace for 20 min at 800−900 °C, cooled in a desiccator, weigh. The calcination and weighing is repeated until obtaining constant weight.
The mass concentration of a standard solution tungsten (), expressed in mg/cm
, calculated by the formula
where is the mass of calcined sludge, mg;
0,7930 — the ratio of tungsten oxide to tungsten.
(Changed edition, Rev. N 1).
3.2. Analysis
3.2.1. Preparation of solutions comparison
In glasses with a capacity of 100 cmis placed 450, 460, 465, 470 and 480 mg of vanadium metal, poured 20 cm
of the mixture of acids and left at room temperature until complete dissolution of batches.
The contents of each beaker was transferred into a measuring flask with a capacity of 50 cm, was diluted to 30−35 cm
water, injected from burettes of various volumes of a standard solution tungsten (tab.1) and adjusted to the mark with water.
Table 1
| Room solution comparison |
The volume of a standard solution of tungsten, cm |
The mass of an element in solution comparisons, mg |
The calculated value of the mass fraction of tungsten in solution comparisons, % | |
| Vanadium |
Tungsten |
|||
| 1 |
5 |
450 |
50 |
10 |
| 2 | 4 |
460 |
40 |
8 |
| 3 | 3,5 |
465 |
35 |
7 |
| 4 |
3 |
470 |
30 |
6 |
| 5 |
2 |
480 |
20 |
4 |
3.2.2. Preparation of samples for analysis
A portion of the sample weighing 0.5 g was placed in a beaker with a capacity of 100 cm, flow 20 cm
of the mixture of acids and dissolved in the cold. The beaker content was transferred into a measuring flask with a capacity of 50 cm
and was adjusted to the mark with water.
3.2.3. X-ray fluorescence determination
Quantometer FRK-10 ready to work. Set the operation mode of the x-ray tube voltage 50 kV, current of 70 mA; a crystal-analyzer SiO(
)*,
0,668 nm; detector scintillation counter with NaI (Tl) crystal; the analytical line
nm 0,1476); the exposure is 100; the number of dimensions is two.
_____________
* Consistent with the original. — Note the manufacturer’s database.
In the working volume of the cell is consistently pour the solutions of the comparison of the sample and again the solutions compare and measure the intensity of analytical lines of tungsten.
The results of measuring the intensity of the tungsten lines, depending on the solutions of the comparison was to measure the samples and post average. Build a calibration curve in the coordinates: the intensity of the analytical lines of tungsten in pulses per second, the calculated value of the mass fraction of tungsten in solution comparing the percentage.
3.3. Obrabotka results
3.3.1. Mass fraction of tungsten () in percent is calculated according to the calibration schedule.
3.3.2. The values of permissible differences when the mass fraction of tungsten from 6 to 8% should not exceed 0.3%.
(Changed edition, Rev. N 1).
3.3.3. The method used in the dispute in the assessment of the quality of the alloys.
