GOST 14339.3-91
GOST 14339.3−91 Tungsten. Methods for determination of phosphorus content
GOST 14339.3−91
Group B59
STATE STANDARD OF THE USSR
TUNGSTEN
Methods for determination of phosphorus content
Tungsten. Methods for determination of phosphorus
AXTU 1709
Date of introduction 1993−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of metallurgy of the USSR
DEVELOPERS
Y. A. Abramov, A. I. Skrypnyk, S. N. Suvorov, G. V. Onuchina, A. G. Matyushina
2. APPROVED AND promulgated by the Decree of Committee of standardization and Metrology of the USSR from
3. REPLACE GOST 14339.3−82
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Paragraph number section |
| GOST 3118−77 |
2.2, 3.2 |
| GOST 3760−79 |
3.2 |
| GOST 3765−78 |
2.2, 3.2 |
| GOST 3772−74 |
2.2 |
| GOST 4142−77 |
2.2 |
| GOST 4204−77 |
3.2 |
| GOST 4461−77 |
2.2 |
| GOST 10484−78 |
2.2 |
| GOST 10652−73 |
3.2 |
| GOST 14919−83 |
2.2 |
| GOST 19275−73 |
3.2 |
| GOST 29103−91 |
1 |
This standard establishes photometric methods for determination of phosphorus content (in mass fraction of phosphorus from from 0.0002 to 0.015%) in the metal tungsten, tungsten oxide, tungsten acid, ammonium paratungstate.
1. GENERAL REQUIREMENTS
General requirements for methods of analysis GOST 29103.
2. METHOD KYLINALOVE ORANGE (in the mass fraction of phosphorus from 0,0002 to 0,01%)
2.1.The essence of the method
The method is based on the formation of complex compounds of the molybdophosphoric heterophilically with selenology orange. Silicon and arsenic complex compound with selenology orange in these conditions do not form.
2.2. Measuring instruments, accessories, reagents and materials
Analytical scale of any type that allows you to weigh a maximum error of 0.0002 g.
Muffle furnace providing heating up to 600−650 °C.
Photoelectrocolorimeter or spectrophotometer of any type.
The unit of household according to GOST 14919.
Ammonium molybdate according to GOST 3765, recrystallized a solution with a mass fraction of 10%.
70 g of salt are dissolved in 400 cmof hot water and filtered through a dense filter. To the solution was added to 250 cm
of ethyl alcohol (rectified), leave for 1 hour to settle, and then the crystals are sucked off on a Buchner funnel, washed several times with water and with alcohol and dried in air.
Ammonium disodium phosphate according to GOST 3772.
Standard solutions
Solution a: 0,4260 g twosemester ammonium phosphate dissolved in water, transferred to a volumetric flask with a capacity of 500 cm, is diluted to the mark with water and mix.
1 cmof the solution contains 0.0002 g of phosphorus.
Solution B: prepare by diluting 1 cmof the solution And water in a volumetric flask with a capacity of 100 cm
.
1 cmof solution B contains 0,000002 grams of phosphorus.
Potassium hydroxide, solution with a mass fraction of 3% and 10%.
Calcium nitrate according to GOST 4142, 12% solution.
Nitric acid according to GOST 4461, diluted 1:1.
Hydrofluoric acid according to GOST 10484.
Selenology orange solution with a mass fraction of 0.1% prepare at least 10 h before use and check the suitability to the reaction of formation of the complex with the molybdophosphoric heterocycles: 10 cmof acetone is added 0.1 cm
(3−4 drops) of the solution kylinalove orange with a mass fraction of 0.1%. If the solution remains colourless or a slightly pink coloration of the reagent suitable for analysis, if the color purple, the reagent complex with the molybdophosphoric heteropolyacid is not the way
et.
2.3.Analysis
2.3.1. Depending on the mass fraction of phosphorus take the sample in accordance with table.1.
Table 1
| Mass fraction of phosphorus, % |
The mass of charge, g |
| From of 0.0002 to 0.0008 inch incl. |
1,0 |
| SV. 0,0008 «0,0015 « |
0,5 |
| «0,0015» 0,004 « |
0,2 |
| «Of 0.004» to 0.01 « |
0,1 |
2.3.2. Suspending the ammonium paratungstate, tungsten acid and tungsten metal, translated into tungsten oxide by calcining at 600−650 °C, placed in a beaker with a capacity of 200−250 cm, add 20 cm
of a solution of potassium hydroxide with a mass fraction of 10% and dissolved on the hot plate until complete dissolution of the sample.
In the analysis of the tungsten metal of the whole sample (see table.1) may be dissolved in a mixture of hydrofluoric and nitric acids (1:1). The resulting solutions evaporated to dryness in a closed plate or sand bath, add 10 cmof water and again evaporated to dryness. Then add 20 cm
of potassium hydroxide solution with a mass fraction of 10% and heated until complete dissolution of the precipitate. After cooling to room temperature the solutions were diluted with water to 100 cm
, add 3 cm
of a solution of calcium nitrate with a mass fraction of 12% and leave for 45 min Then add 1 cm
of calcium nitrate and leave it for 15 min. Then the solutions were filtered through a double filter of «blue ribbon» and washed 8−10 times with a solution of potassium hydroxide with a mass fraction of 3%. The filter cake is dissolved in 10 cm
of hot nitric acid (1:1). The solutions were quantitatively transferred to a volumetric flask with a capacity of 100 cm
, diluted with distilled water to 80 cm
, add 10 cm
of molybdate ammonium solution with a mass fraction of 10% and leave the solution for 10 min and Then pipette is introduced into the bulb 5 cm
kylinalove orange solution with a mass fraction of 0.1%, made up to the mark with water and mix. The solutions were left for 45 min for formation of stable complex compounds. At the expiration of this time the optical density of colored solution is measured on a photoelectrocolorimeter with a green light filter (wave length 540 nm) in a cuvette with a thickness of the light absorbing layer was 50 mm. In a solution of comparison when measuring the optical density of the solution is used in the reference experiment. At the same time spend three reference experiment for the determination of phosphorus reagents. The solution to the mean value of optical density used as a comparison solution.
The phosphorus content find for the calibration of gr
the Afik.
2.3.3. To build a calibration curve in a volumetric flask with a capacity of 100 cmpoured from 0.5 to 5 cm
(every 0.5 cm
) of a standard solution dosagedosage ammonium phosphate (solution B), poured 10 cm
of nitric acid (1:1) and add distilled water to approximately 80 cm
.
Then to the solution was added 10 cmof molybdate ammonium solution with a mass fraction of 10% and left for 10 min to develop the color of the resulting heteroalicyclic. Then pipette add 5 cm
kylinalove orange solution with a mass fraction of 0.1% and topped to the mark with water. The resulting solution was stirred and left for 45 min for formation of stable colored complex compounds. After a specified time, measure the optical density of colored solution on a photoelectrocolorimeter with a green light filter (wave length 540 nm) in a cuvette with a thickness of the light absorbing layer was 50 mm. In a solution of comparison when measuring the optical density of the solution is used in the reference experiment with an average value of optical density from three parallel experiments. On the found values of optical densities of solutions and their corresponding concentration of phosphorus build a calibration curve
.
2.4. Processing of the results
2.4.1. Mass fraction of phosphorus () in percent is calculated by the formula
where is the mass of phosphorus in the sample solution found by the calibration schedule g;
— the weight of the portion,
2.4.2. Allowable absolute differences of the results of three parallel measurements at a confidence level 
Table 2
| Mass fraction of phosphorus, % |
Allowable absolute differences, % |
| From 0,0002 to 0,001 incl. |
0,00008 |
| SV. 0,001 «0,003 « |
0,0004 |
| «Of 0.003» to 0.01 « |
0,0008 |
3. METHOD WITH the USE of ASCORBIC ACID AND POTASSIUM ARMENONVILLE (when the mass fraction of phosphorus from 0.0005 to 0.015%)
3.1. The essence of the method
The method is based on the formation of the molybdophosphoric heteroalicyclic and ascorbic acid in the presence of potassium animeillustrated after separation of the phosphorus from the tungsten to the hydroxide of beryllium.
3.2. Measuring instruments, accessories, reagents and materials.
The generic type ion meter EV-74.
Sulfuric acid according to GOST 4204, diluted 1:4.
Hydrochloric acid according to GOST 3118, diluted 1:1.
The chelating agent Trilon B, disodium salt of ethylenediaminetetraacetic acid according to GOST 10652 with a mass fraction of 100 g/DM; prepare by heat.
Beryllium sulfate, 1 DMof solution contains 1 g of beryllium. Dissolve 19,65 g of salt per 1 DM
of water.
Ammonia water according to GOST 3760.
The washing liquid: 500 cmwater flow 30 cm
of the solution Trilon B (100 g/DM
), 15 cm
of ammonia and diluted to 600 cm
water. Ammonium bromide according to GOST 19275.
Acid chloride, with a density of 1.32 diluted 1:1.
Ammonium molybdate according to GOST 3765, recrystallized (see p.2.2).
The reaction mixture of 1.74 g of ammonium molybdate dissolved in 100 cm of water is added 21 cmsulfuric acid, cooled and made up to 250 cm
with water.
Ascorbic acid, a solution of concentration 20 g/DM.
Potassium armanavicius (antimoniate potassium), solution concentration of 3 g/DM.
Indicator paper «Congo».
As well as measuring instruments, accessories, reagents and materials specified in
claim 2.2.
3.3. Preparation of samples for analysis
Depending on the mass fraction of phosphorus take the sample in accordance with table.3.
Table 3
| Mass fraction of phosphorus, % |
The mass of charge, g |
| From 0.0005 to 0.004 incl. |
0,4 |
| «0,0007» 0,005 « |
0,3 |
| «To 0.001» 0,007 « |
0,2 |
| «Of 0.002» to 0.015 « |
0,1 |
3.3.1. The metal tungsten is dissolved by heating in a platinum Cup in a mixture of 5 cmhydrofluoric and 1 cm
of nitric acid. The solution is evaporated to dryness, poured 5cm
of water and again evaporated to dryness. Pour 10 cm
of a solution of potassium hydroxide and dissolved by heating. The contents of the Cup are transferred into the glass.
3.3.2. The ammonium paratungstate, tungsten acid is transferred to tungsten oxide by calcining at a temperature of 600−650 °C.
3.3.3. A portion of the tungsten oxide is dissolved by heating in 10 cmof a solution of potassium hydroxide.
3.4. Analysis
The obtained alkaline solutions are neutralized by indicator paper «Congo» (pH 5) with sulfuric acid (1:4). Poured 75 cmof the solution Trilon In 8 cm
of beryllium sulfate solution and boil for 2−3 minutes In hot solution with a volume of 100−120 cm
pour the ammonia solution until pH 9.5−10 and again boil for 2−3 min. the Solution was cooled in running water and filtered off the precipitate on a filter of medium density.
The filter residue is washed 8−10 times with wash fluid.
The filter cake is dissolved in 30 cmof hydrochloric acid (1:1).
The filtrate collected in a beaker with a capacity of 50 cm*, add 3 cm
of perchloric acid (1:1) and the solution is evaporated to release heavy fumes of perchloric acid. Salt is dissolved by heating in 25 cm
of water. The solution is poured into a measuring flask with a capacity of 50 cm
(if the solution to precipitate, it was filtered), pour 2.5 cm
of the reaction mixture, 5 cm
of ascorbic acid and 0.5 cm
of a solution of potassium animeillustrated. After perelivania of each reagent a solution is mixed.
______________
* If the arsenic content in the sample exceeds twice the phosphorus content, after dissolution of the hydroxide of beryllium in the environment hydrochloric acid add 0.1 g of ammonium bromide and evaporated to dryness. Again add 10 cmof hydrochloric acid density of 1.19 g/cm
and 0.1 g of ammonium bromide and evaporated to dryness.
Optical density of the solution is measured after 10 minutes on the spectrophotometer (wavelength 825 nm) or photoelectrocolorimeter with a red light filter (wavelength 750 nm) in a cuvette with a thickness of the light absorbing layer was 50 mm.
As a solution comparison solution is used in the reference experiment with an average value of optical density of three parallel results on the phosphorus content in Rea
chiwah.
3.5. Construction of calibration curve
In glasses with a capacity of 50 cmis taken from 1 to 10 cm
of a standard solution of phosphorus Used, pour 3 cm
of a solution of perchloric acid (1:1). The solution was evaporated to copious fumes of perchloric acid. To the cooled solution poured 25 cm
* and transfer the solution into volumetric flask with a capacity of 50 cm
, pour 2.5 cm
of the reaction mixture, 5 cm
of a solution of ascorbic acid and 0.5 cm
animeillustrated potassium and then do as indicated in the analysis of section 3.4.
_______________
* The text matches the original. — Note the manufacturer’s database.
3.6. Processing of the results
3.6.1. Mass fraction of phosphorus () in percent is calculated by the formula
where is the mass of phosphorus was found in the calibration schedule g;
— the weight of the portion of the sample,
3.6.2. The discrepancy between the results of parallel measurements at a confidence level 
Table 4
| Mass fraction of phosphorus, % |
Allowable absolute differences, % |
| From 0.0005 to 0.001 incl. |
0,0002 |
| SV. Of 0.001 «to 0.002 « |
0,0004 |
| «Of 0.002» to 0.005 « |
0,0005 |
| «Of 0.005» to 0.015 « |
0,001 |
