GOST 12347-77

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  ГОСТ 12347-77

GOST 12347−77 Steel alloyed and high alloy. Methods for determination of phosphorus (Change No. 1)

GOST 12347−77

Group B39

STATE STANDARD OF THE USSR

STEEL ALLOYED AND HIGH-ALLOYED

Methods for determination of phosphorus

Alloy and high-alloy steels. Methods for determination of phosphorus

AXTU 0809

Date of introduction 1978−01−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of ferrous metallurgy of the USSR

PERFORMERS

I. N. Golikov, A. A. Fedorov (head of subject); F. V. Czerniakow; O. I. Putintseva

2. APPROVED AND promulgated by the decree of the State Committee of standards of Ministerial Council of the USSR from 08.06.77 N 1435

3. REPLACE GOST 12347−77* in addition to the General instructions
________________
* Probably, the error of the original. Should read: REPLACE GOST 12347−66, in addition to General instructions. — Note the manufacturer’s database.

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Validity extended until 01.07.98 by the Resolution of Gosstandart of the USSR from 20.10.87 N 3950*
_______________
* Expiration removed by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification. (IUS N 11 1995). — Note the CODE.

6. REPRINT (March 1989) with amendment No. 1, approved in October 1987 (ICS 1−88)


This standard specifies the photometric and extraction-photometric methods for the determination of phosphorus (at a mass fraction of phosphorus from 0.002 to 0.25%) in the alloy and high-alloy steels.

A visual colorimetric method for the determination of phosphorus and titrimetric method for the determination of phosphorus, the recommended in appendices 1 and 2.

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 20560−81.

2. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF PHOSPHORUS

2.1. Determination of phosphorus in steels with a mass fraction of tungsten up to 5%, Nickel up to 5%, chromium (with respect to the mass fraction of chromium to the mass fraction of phosphorus not more than 200)

2.1.1. The essence of the method

The method is based on the reaction of formation of the molybdophosphoric yellow heteroalicyclic N[P (MoO)]· · Hand subsequent recovery in nitrogen-rate of the solution to a blue compound by ascorbic acid, or in hydrochloric acid medium with ions of bivalent iron in the presence of potassium respectively animeillustrated or hydrochloride of hydroxylamine. The complex is stable at least 1.5 h. the Use of nitric acid to dissolve the sample prevents the volatilization of phosphorus in the form of phosphine gas.

Trivalent phosphorus of the pre-oxidized to pentavalent with potassium permanganate.

Vanadium for the mass concentration of up to 5% definition does not interfere. Interfere with titanium, zirconium and niobium.

Interfering with the action of arsenic can be eliminated by Stripping it in the form of trichloride arsenic.

Manganese interferes with the determination when the mass fraction of its more than 3%.

(Changed edition, Rev. N 1).

2.1.2. Equipment, reagents

Spectrophotometer type SF-46 or type photoelectrocolorimeter KFK-2 or another type, providing the same measurement accuracy.

Nitric acid GOST 4461−77 and diluted 1:1, 1:2, 1:4, 1:10 and 1:100.

Hydrochloric acid by the GOST 3118−77, diluted 1:1, 1:3, 1:100 and a density of 1.105 g/cm. For preparation of a solution of hydrochloric acid with a density of 1.105 g/cm560 cmof hydrochloric acid diluted with water to 1 DMand stirred.

Hydrofluoric acid according to GOST 10484−78.

Sodium carbonate according to GOST 83−79.

Potassium permanganate according to GOST 20490−75, a solution with a mass concentration of 40 g/DM.

Sodium atomistically according to GOST 4197−74, a solution with a mass concentration of 50 g/DM.

Ammonium bromide according to GOST 19275−73, a solution with a mass concentration of 100 g/DM.

Ammonia water according to GOST 3760−79 and diluted 1:1, 1:100.

Hydroxylamine hydrochloride according to GOST 5456−79, a solution with a mass concentration of 200 g/DM.

Ethyl alcohol GOST 18300−87.

Ammonium molybdate according to GOST 3765−78, recrystallized, solution with a mass concentration of 50 g/DM, the solution should be stored in polyethylene or quartz container. For recrystallization 250 g of reagent was dissolved in 400 cmof water when heated to 70−80°C, the solution was filtered through filter «blue ribbon», cooled to room temperature, poured, with stirring, 300 cmof ethyl alcohol, allow sediment to settle for 1 h and filtered it, the filter «white ribbon» placed in a Buchner funnel under vacuum, using a water vacuum pump. Precipitate was washed 2−3 times with ethanol and dried in air.

Potassium phosphate according to GOST odnosemjannyj 4198−75, twice recrystallized: 100 g of reagent was dissolved in 150 cmof water when heated, and then poured the solution in a thin stream in a porcelain Cup, stirring vigorously with a glass rod. When the solution cools to room temperature, the Cup with the crystals cooled in cold running water, occasionally stirring with a glass rod. After cooling, the crystals filtered under vacuum, using a water vacuum pump, a porous glass plate funnel and washed with 2 times 5 cmof ice water.

The filter cake is dissolved in 4−5 receptions in 80 cmof hot water and the crystallization repeated. The potassium phosphate crystals of single dried at a temperature of (110±5)°C to constant weight.

Standard solutions of potassium phosphate of single:

the solution And the mass concentration of phosphorus of 0.0001 g/cm:0,4393 g of single potassium phosphate was placed in a volumetric flask with a capacity of 1 DM, is dissolved in 100 cmof water, made up to the mark with water and mix;

solution B with a mass concentration of phosphorus 0,00001 g/DM:10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix; prepare before use.

Ascorbic acid, a solution with a mass concentration of 20 g/DM.

The reaction mixture of 1.74 g of ammonium molybdate dissolved in 100 cmof water when heated, add 50 cmof nitric acid, cool, add water to 250 cmand stir; cook before eating.

Potassium antimoniate, according to normative-technical documentation; a solution with a mass concentration of 3 g/DM.

Iron (III) chloride according to GOST 4147−74, a solution with a mass concentration of 80 g/DM:40 g of ferric chloride dissolved in 200−300 cmof water when it is heated, filtered in a volumetric flask with a capacity of 500 cm, cooled, made up to the mark with water and mix.

Instead of a solution of ferric chloride can be used ferric nitrate solution with a mass concentration of 17 g/DM. 8.5 g of iron carbonyl was placed in a beaker with a capacity of 400 cm, gradually add 150 cmof nitric acid, diluted 1:2, and dissolve the sample when heated. The solution was filtered in a volumetric flask with a capacity of 500 cm, the glass and the filter cake was washed 4−5 times with hot water. The solution was cooled, made up to the mark with water and mix.

Acid chloride, with a density of 1.54 g/cm.

(Change

a daily edition, Rev. N 1).

2.1.3. Analysis

2.1.3.1. 0.5 g of steel (in mass fraction of phosphorus up to 0.01%) or 0.2 g of steel (in mass fraction of phosphorus above 0.01%) were placed in a glass with a capacity of 400 cm, flow 10 cmof nitric acid, 30 cmof hydrochloric acid and dissolved by heating.

The solution is diluted with hot water up to 200−250 cm, heated to boiling and allowed to settle upset tungsten (partly silicic) acid for 30 min.

The precipitate was filtered off on the filter «blue ribbon» with the addition of a small amount of ashless paper pulp and collect the filtrate in a beaker with a capacity of 500 cm. The filter cake is washed 6−8 times with hot nitric acid, diluted 1:100. Filter the precipitate tungsten acid drop. The solution was evaporated to wet condition salts, poured 5−7 cmof nitric acid and evaporated to wet condition salts. Surging nitric acid and the evaporation repeated two more times.

Pour 5 cmof nitric acid, 10−15 cmof water and heated to dissolve the salts. The precipitate of silicic acid (and residual tungsten acid) is filtered off at the filter «white ribbon» containing a small amount of ashless paper pulp, and collect the filtrate in a beaker with a capacity of 250 cm. The filter cake is washed 6−8 times with hot nitric acid, diluted 1:100.

The filter with the residual silicic acid and the residual tungsten acid drop.

Note. When the mass fraction of silicon in the analyzed sample is more than 1.5% of the filter with the precipitate of silicic acid is placed in a platinum crucible, dried, incinerated and calcined at 800−900°C. the Precipitate is moistened with 2−3 drops of water, add 8−10 drops of nitric acid, 3−5 ml of hydrofluoric acid and cautiously evaporate the contents of the crucible to dryness. The residue is fused in a crucible with 1−2 g of sodium carbonate at 1000−1100°C. the Melt is leached with nitric acid, diluted 1: 10, boiling. The crucible is washed with water and the resulting solution was attached to the main filtrate.

If the steel contains more than 3% manganese, the solution was evaporated to dryness. The remainder is kept in a drying Cabinet at a temperature of (140±5)°C for 1 h.

To the residue add 5−10 cmof hydrochloric acid and evaporated to dryness. This operation is carried out 4 more times. Further analysis of the lead since the distillation of arsenic.


The solution is heated to boiling, are added dropwise a solution of potassium permanganate before rolling the brown precipitate of manganese dioxide (1−2 cm) and boil for 2−3 min. To the boiling solution is poured dropwise a solution of sodium attestatio to dissolve the residue. The solution was evaporated to dryness, poured 10 cmof hydrochloric acid and again evaporated to dryness.

When the mass fraction of arsenic in the analyzed sample is more than 10% of the mass fraction of phosphorus, or if the mass fraction of arsenic is unknown, the latter is removed by Stripping in the form of trichloride arsenic. For this purpose, the dry residue poured 10 cmof hydrochloric acid and evaporate the solution to dryness. The dry residue was dissolved with heating in 15 cmof hydrochloric acid, poured 10 cmof a solution of bromide of ammonium, and evaporate the solution until a state of moist salts. Then pour 10 cmof hydrochloric acid and again evaporated to wet condition salts. Surging hydrochloric acid and evaporation of the solution to the state of moist salts again.

Pour 15 cmof hydrochloric acid diluted 1:3 and heated to dissolve the salts. The solution was transferred to a volumetric flask with a capacity of 100 cm, cooled, made up to the mark with water and mix.

Further, determination is carried out by one of the methods indicated in the claims. 2.1.3.

2 and 2.1.3.3.

2.1.3.2. Determination of phosphorus (0,002−0,04%) was used as a reducing agent ascorbic acid in the presence of potassium animeillustrated.

Aliquot part of the solution is equal to 20 cm(when the mass fraction of phosphorus from 0.002 to 0.02%) or 10 cm(when the mass fraction of phosphorus in excess of 0.02−0.04%) are placed in two glasses with a capacity of 100 cm, add 1 cmof perchloric acid and evaporated to start the selection of its vapors.

Salt is dissolved in 20 cmof water when heated. The solutions is cooled to a temperature at least 20 °C. In one of the glasses poured 5 cmof the reaction mixture, 10 cmof ascorbic acid solution and 1 cmof a solution of potassium animeillustrated.

The solution was transferred to volumetric flask with a capacity of 100 cm, made up to the mark with water and mix. Optical density of the solution is measured after 30 minutes on the spectrophotometer at a wavelength of 880 nm or photoelectrocolorimeter, the interval of light absorption 680−900 nm in a cuvette with a layer thickness of 50 mm at a mass fraction of phosphorus from 0.002 to 0.02% or in a cuvette with a layer thickness of 20 mm with mass fraction of phosphorus above 0.01−0,04%, applying the solution comparison aliquoting the second part containing the above reagents in the same quantities, with the exception of the reaction mixture.

The mass of phosphorus (ág), as amended by the reference experiment for the calibration find graphics, built with the use of ascorbic sour

you.

2.1.3.- 2.1.3.2. (Changed edition, Rev. N 1).

2.1.3.3. Determination of phosphorus (0,01−0,25%) was used as a reducing agent ions of divalent iron in the presence of hydroxylamine hydrochloride

In two volumetric flasks with a capacity of 100 cmis placed aliquote part of the resulting solution equal to 20 cm(when the mass fraction of phosphorus of 0.01−0.06%), 10 cm(when the mass fraction of phosphorus in excess of 0.06 to 0.12%) or 5 cm(for the mass concentration of phosphorus in excess of 0.12 to 0.25%). In each flask pour 4 cmof solution of ferric chloride (or ferric nitrate), ammonia solution (1:1) prior to deposition of ferric hydroxide which is then dissolved by adding dropwise hydrochloric acid (density of 1.105 g/cm). Add 10 cmof a solution of hydroxylamine hydrochloride.

The solutions were slowly heated up to bleaching, boiling, avoiding them. If the solutions remain yellowish, you need to add 1−2 drops of ammonia solution (1:1), the appearance of turbidity add 2−3 drops of hydrochloric acid (density of 1.105 g/cm) and heated to boiling. In the case that solutions remain a yellowish color, which leads to underestimated results, the analysis should be repeated.

The solutions were cooled. In one of the volumetric flasks poured 10 cmof hydrochloric acid (density of 1.105 g/cm), mix and add dropwise with continuous stirring 8 cmof a solution of molybdate of ammonium. The solution was stirred for 1−2 min until appearance of a blue color, made up to the mark with water and mix. After 10 minutes measure the optical density on the spectrophotometer at a wavelength of 830 nm or photoelectrocolorimeter, the range of 680−900 nm light absorption in a cuvette with a layer thickness of 50 mm, applying a solution of comparison aliquoting the second part containing the above reagents in the same quantities, with the exception of molybdate ammonium solution.

The mass of phosphorus (in g), as amended by the reference experiment for the calibration find graphics, built with the use of hydroxylamine hydrochloride.

(Added, Rev.

N 1).

2.2. Determination of phosphorus in chromium and chromium-Nickel steels

2.2.1. The essence of the method

The method is based on the reaction of formation of the molybdophosphoric yellow heteroalicyclic and subsequent recovery in nitrogen-rate of the solution to a blue complex compound with ascorbic acid or in hydrochloric acid medium with ions of bivalent iron in the presence of potassium respectively animeillustrated or hydrochloride of hydroxylamine.

A sample of steel is dissolved in a mixture of nitric and hydrochloric acids. Chrome is oxidized to hexavalent in the environment neccersarily nitrate to ammonia. For complete oxidation of trivalent phosphorus to pentavalent apply potassium permanganate.

Phosphorus is precipitated with ferric hydroxide collector in the ammonia environment. The precipitate was filtered off and dissolved in hydrochloric acid.

Molybdenum definition, does not prevent.

Manganese interferes with the mass fraction of its more than 3%.

2.2.2. Reagents

Ammonium neccersarily according to GOST 20478−75, a solution with a mass concentration of 250 g/DM.

The rest of the reagent according to claim 2.1.2.

2.2.1; 2.2.2. (Changed edition, Rev. N 1).

2.2.3. Analysis

0.5 g of steel placed in a beaker with a capacity of 400 cm, add 10 cmof nitric acid, 30 cmof hydrochloric acid and dissolved by heating.

To a solution of the reference experiment add 4 cmof solution of ferric chloride (or ferric nitrate).

The solution was evaporated to dryness, add 5−10 cmof nitric acid and evaporate the contents of the glass to wet salts. This operation is repeated again. The solution is poured 5 cmof nitric acid, heated, diluted with water up to 80−100 cm, and heated nearly to boiling.

The precipitate of silicic acid is filtered off, the filter «white ribbon» containing a small amount of ashless paper pulp. The filtrate collected in a beaker with a capacity of 400 cm. The filter cake is washed 6−8 times with hot nitric acid, diluted 1:100.

Filter the precipitate of silicic acid is discarded.

Note. When the mass fraction of silicon in the analyzed sample is more than 1.5% of the filter with the precipitate of silicic acid is placed in a platinum crucible, dried, incinerated and calcined at 800−900°C. the Precipitate is moistened with 2−3 drops of water, add 8−10 drops of nitric acid, 3−5 cmhydrofluoric acid and cautiously evaporate the contents of the crucible to dryness.

The residue is fused in a crucible with 1−2 g of sodium carbonate at 1000−1100°C. the Melt is leached with nitric acid, diluted 1:10, boiling. The crucible is washed with water and the resulting solution was attached to the main filtrate.

If the steel contains more than 3% manganese, the solution was evaporated to dryness. The remainder is kept in a drying Cabinet at a temperature of (140±5)°C for 1 h. To the residue add 5−10 cmof hydrochloric acid and evaporated to dryness. This operation is carried out 4 more times. Further analysis of the lead since the distillation of arsenic.


To the filtrate poured 20 cmof the solution naternicola ammonia and heat the solution until oxidation to hexavalent chromium. To the boiling solution add 1−2 cmof solution of potassium permanganate and boiled until precipitation of manganese dioxide, then pour a solution of ammonia until the full allocation of hydroxide of iron and about 0.5 g of ammonium naternicola. The contents of the glass boil for 1−2 min, allow the residue to soak for 3−5 min and then filtered, the precipitate on the filter «white ribbon».

The glass and the filter cake was washed 5−6 times with a hot solution of ammonia, diluted 1:100. Iron hydroxide washed from the filter with water into the glass, which conducted the deposition. The filter was washed with 40 cmof hot hydrochloric acid, diluted 1:1 with the addition of a few drops of solution of sodium and attestatio 5−6 times with hot water. Wash liquid collected in the beaker with the sediment.

The contents of the beaker is heated to dissolve the residue and evaporate the solution to about 5−10 cm.

When the mass fraction of arsenic in the analyzed sample is more than 10% of the mass fraction of phosphorus, or if the mass fraction of arsenic is unknown, the latter is removed by Stripping in the form of trichloride arsenic. For this hydrochloric acid solution is evaporated to dryness. To the dry residue poured 10 cmof hydrochloric acid and again evaporated to dryness. The dry residue was dissolved with heating in 15 cmof hydrochloric acid, poured 10 cmof a solution of ammonium bromide and the solution is evaporated to wet condition salts, then pour 10 cmof hydrochloric acid and again evaporated to wet condition salts. Surging hydrochloric acid and evaporation of the solution to the state of moist salts again.

The solution was poured 15 cmof hydrochloric acid diluted 1:3 and heated to dissolve the salts.

The solution was transferred to a volumetric flask with a capacity of 100 cm, cooled, made up to the mark with water and mix.

Measure the optical density as indicated in the claims. 2.1.3.2, 2.1.3.3.

(Modified redakts

ia, Rev. N 1).

2.3. Determination of phosphorus in steels with a mass fraction of titanium up to 5%, zirconium up to 5%, niobium up to 5%, tungsten and molybdenum up to 20%

2.3.1. The essence of the method

The method is based on the reaction of formation of the molybdophosphoric yellow heteroalicyclic and subsequent recovery in nitrogen-rate of the solution to a blue complex compound with ascorbic acid or in hydrochloric acid medium with ions of bivalent iron in the presence of potassium respectively animeillustrated or hydrochloride of hydroxylamine.

A sample of steel is dissolved in a mixture of nitric and hydrochloric acids, containing ammonium molybdate. Remove the chlorine ions by repeated evaporation of the solution to dryness with nitric acid. The rest is kept at (140±5)°C for the oxidation of trivalent phosphorus to pentavalent and the bulk of the chromium to hexavalent.

Phosphorus, chromium, tungsten and molybdenum are separated alkali from iron, titanium, zirconium and niobium remaining in the sediment. Then the phosphorus is separated from chromium, tungsten and molybdenum by coprecipitation with header-hydroxide of calcium and iron in the potassium hydroxide solution.

(Changed edition, Rev. N 1).

2.3.2. Reagents

Potassium hydroxide, solutions with a mass concentration of 150 g/l, 20 g/land 10 g/DM. The reagent must be practically carbonates. Why it is prepared from washed with water potassium hydroxide. To check to 50 cmof the reagent is added 5 cmof a solution of barium chloride according to GOST 4108−72 (50 g/DM) and mixed. When white precipitate think that the content of carbonates unacceptably high, with a light clouding of the reagent is usable. Store in a sealed plastic container.

Calcium carbonate according to GOST 4530−76.

Calcium nitrate according to GOST 4142−77, solution: is prepared as follows: 60 g of CA (NO)· 4 Ndissolved in ABOUT 200−300 cmof water, the solution filtered through the filter «white ribbon» in a volumetric flask with a capacity of 500 cm, cooled, made up to the mark with water and mix.

When pollution nitrate calcium phosphorus reagent, purify as follows: 60 g of CA (NO)· 4 Nand ABOUT 0.4 g of ferric chloride dissolved in 200−300 cmof water when heated, add dry calcium carbonate to the formation of excess equal to approximately 2−3 g, boil and give the residue to stand for 15−20 min Under a layer of iron hydroxide should remain a white precipitate of calcium carbonate. The solution was filtered through a filter «white ribbon» in a volumetric flask with a capacity of 500 cm. The precipitate on the filter, not washing, is discarded. The solution was cooled, made up to the mark with water and mix.

1 cmof the resulting solution contains about 0.02 g of calcium.

Carbonyl iron, high-purity, nitric-acid solution; prepared as follows: 5 g of iron carbonyl was placed in a beaker with a capacity of 400 cm, gradually add 150 cmof nitric acid, diluted 1:2, and dissolve the sample when heated. The solution was filtered in a volumetric flask with a capacity of 500 cm, the glass and the filter cake was washed 4−5 times with hot water.

The solution was cooled, made up to the mark with water and mix.

1 cmof the resulting solution contains 0.01 g of iron.

A mixture of nitrate solution of calcium and nitrate of iron; prepared as follows: 500 cmof a solution of calcium nitrate is added to 250 cmof solution of nitrate of iron and stirred.

The washing liquid; prepared as follows: to 1 DMof potassium hydroxide solution (10 g/DM) add 30 cmof a mixture of solutions of calcium nitrate and iron nitrate and stirred. After 10−15 min the solution was filtered through a double filter of «white ribbon». The filter with sediment, not washing, is discarded. The solution is prepared before use.

Other Rea

assets — paragraph 2.1.2.

2.3.3. Analysis

0.5 g of steel placed in a beaker with a capacity of 250 cm, add 20 cmof molybdate ammonium solution, 10 cmof nitric acid and 30 cmof hydrochloric acid.

The charge is dissolved by heating and the solution evaporated to dryness on a boiling water bath or gently evaporated on a plate, covered with a thick layer of asbestos. Add 10 cmof nitric acid and evaporate the solution to dryness on a boiling water bath. This operation is repeated again. The dry residue cautiously heated on a stove until the termination of allocation of oxides of nitrogen, then on the stove or in an oven at (140±5)°C for 1 h.

To the dry residue add 5−10 cmof hydrochloric acid and heated to dissolve the salts. At the same time on the bottom of the glass remains insoluble compounds of titanium, zirconium, niobium, tungsten and molybdenum. Add 40−50 cmof hot water and boil for 2−3 min.

Add a solution of potassium hydroxide (150 g/DM) to alkaline reaction on indicator paper Congo and 70 cmin excess. The solution is stirred and gently heated to boiling and continue to heat on a boiling water bath for 25−30 min. allow to settle sediment for 5−7 min.

The solution was filtered through a filter «white ribbon» with a diameter of 15 cm in a glass with a capacity of 600 cmprinted on it a label at the level of 500 cm. The glass is washed 5−6 times and the precipitate on the filter 18−20 times a hot solution of potassium hydroxide (20 g/DM). The precipitate is discarded. The filtrate is cooled, diluted with water to 500 cm.

To the filtrate add 15 cmof a mixture of solutions of nitrate of calcium and carbonyl iron, and stirred. After 5 minutes, add another 6 cmof this mixture. After 15 minutes (and no more than 2 hours) the precipitate of hydroxide of calcium and iron containing phosphorus is filtered at the filter «white ribbon» with the addition of a small amount of ashless paper pulp. The glass is washed 4−5 times and the filter cake wash 7−8 times liquid.

The precipitate of calcium hydroxide and iron on the filter is dissolved in 40 cmof hot hydrochloric acid, diluted 1:1, while the funnel covered with watch glass. The filtrate is collected in a glass, which conducted the deposition. The hour glass is washed with hot hydrochloric acid, diluted 1:100, the filter was washed with the same acid for 7−8 times.

When the mass fraction of arsenic in the analyzed sample is more than 10% of the mass fraction of phosphorus, or if the mass fraction of arsenic is unknown, the latter is removed by Stripping in the form of trichloride arsenic. To the resulting hydrochloride solution was evaporated to dryness, add 10 cmof hydrochloric acid and again evaporated to dryness. This operation is repeated again. The dry residue was dissolved with heating in 15 cmof hydrochloric acid, poured 10 cmof a solution of bromide of ammonium, and evaporate the solution until a state of moist salts. This operation is repeated again. Add 15 cmof hydrochloric acid diluted 1:3 and heated to dissolve the salts. When the deposition of a silicic acid solution diluted with hot water up to 80−100 cmand heated to boiling.

The precipitate of silicic acid is filtered off on a medium density filter that contains a small amount of ashless paper pulp. The filtrate collected in a beaker with a capacity of 400 cm. The glass and the filter cake is washed 6−8 times with hot hydrochloric acid, diluted 1:100. Retain the filtrate (stock solution).

Filter the precipitate of silicic acid is placed in a platinum crucible, dried, incinerated and calcined at (800−900)°C. the Precipitate is moistened with 2−3 drops of water, add 8−10 drops of nitric acid, 3−5 cmhydrofluoric acid and cautiously evaporate the contents of the crucible to dryness.

The residue is fused in a crucible with 1−2 g of sodium carbonate at (1000−1100) °C. the Melt is leached with hot nitric acid. diluted 1:10, boiling. The resulting solution was attached to the main solution. The crucible is washed with hot water, adding the wash liquid to the main solution.

The solution was evaporated to 5−10 cm, transferred to a volumetric flask with a capacity of 100 cm, cooled, made up to the mark with water and mix.

Measure the optical density as indicated in the claims. 2.1.3.2, 2.1.3.3.

(Modified R

acaccia, Rev. N 1).

2.4. Construction of calibration curve

2.4.1. Construction of calibration curve was used as a reducing agent ascorbic acid in the presence of potassium animeillustrated

Six glasses with a capacity of 100 cmplaced 0,2; 0,5; 1,0; 1,5; 2,0; 3,0 cmstandard solution B of single potassium phosphate, which corresponds to: 2, 5, 10, 15, 20, 30 mcg phosphorus. The seventh glass with a capacity of 100 cmis used for the reference experiment on the phosphorus content in the reagents.

In each glass pour 1 cmof perchloric acid and evaporate the solution to start the selection of its vapors. Further analysis are as described in section 2.1.3.2.

On the found values of optical density-adjusted reference experiment and a corresponding mass of phosphorus build a calibration curve.

2.4.2. Construction of calibration curve was used as the reducing agent ions of divalent iron in the presence of hydroxylamine hydrochloride

Nine volumetric flasks with a capacity of 100 cmplaced 0,5; 1,0; 1,5; 2,0; 3,0; 4,0; 5,0; 6,0; 6,5 cmstandard solution B of single potassium phosphate, which corresponds to 5, 10, 15, 20, 30, 40, 50, 60, 65 mcg phosphorus. Tenth a volumetric flask with a capacity of 100 cmis used for the reference experiment on the phosphorus content in the reagents.

In each flask pour 5 cmof a solution of ferric chloride (or nitrate of iron), 20 cmof water and ammonia solution (1:1) prior to deposition of ferric hydroxide which is then dissolved by adding dropwise hydrochloric acid (density of 1.105 g/cm) and further analysis are as described in section 2.1.3.3.

On the found values of optical density-adjusted reference experiment and a corresponding mass of phosphorus build a calibration curve.

2.4.1; 2.4.2. (Changed edition, Rev. N 1).

2.5. Processing of the results

2.5.1. Mass fraction of phosphorus () in percent is calculated by the formula

,

where is the mass of phosphorus was found in the calibration schedule, mcg;

 — weight of steel taken for the measurement of ICG.

(Changed edition, Rev. N 1).

2.5.2. The allowable divergence between the outermost of the three parallel results at confidence probability P=0.95 does not exceed the values given in the table.

3. Extraction-photometric method for the determination of phosphorus in steels containing up to 2% titanium, up to 0.5% zirconium, 1% niobium, 10% tungsten, molybdenum, Nickel and chromium

3.1. The essence of the method

The method is based on extraction of phosphorus from environment rate of isobutyl alcohol in the form of the molybdophosphoric yellow complex, which restores the organic phase (preliminarily separating the aqueous layer) to a blue complex compound (= 725 nm) tin chloride. Extract homogenizer acetone and complete analyses are read. The blue color complex compounds stable for at least 3 hours.

A sample of steel is dissolved in a mixture of nitric and hydrochloric acids. The solution was evaporated with perchloric acid prior to the determination of its vapour. If the steel contains chromium, it is removed by Stripping chloride gromila. Residual chrome restore sanitarily sodium.

Interfering with the action of zirconium, of niobium, of tungsten and titanium (with a mass fraction of less than 1%) eliminated by adding ammonium fluoride. Molybdenum and Nickel do not interfere with the determination.

The arsenic content of less than 0,003% does not interfere with the determination of phosphorus. Arsenic content of more than 0,003% and tungsten is less than 3%, the arsenic distilled off in the form of trichloride arsenic.

3.2. Equipment, reagents

Spectrophotometer type SF-46 or photoelectrocolorimeter KFK-2 or another type, providing the same measurement accuracy.

The acid chloride.

Sanitarily sodium (sodium sulfite) anhydrous GOST 195−77, solution, saturated at room temperature.

Nitric acid GOST 4461−77.

Hydrochloric acid by the GOST 3118−77.

Ammonium fluoride according to GOST 4518−75, a solution with a mass concentration of 20 g/DM. The solution should be stored in a plastic vessel.

Sulfuric acid GOST 4204−77 and 1 n solution; prepared as follows: to 700 cmof water was added 20 cmof sulfuric acid, stirred and cooled.

Ammonium molybdate according to GOST 3765−78, recrystallized (2.1.2) sulfate solution with a mass concentration of 50 g/l; prepared as follows: 50 g of the reagent was placed in a beaker with a capacity of 400 cm, add 200 cmof water and dissolved by heating. The solution was filtered in a volumetric flask with a capacity of 1 DM, cooled, carefully added 115 cmof sulphuric acid, diluted to the mark with water and mix. The solution should be stored in polyethylene or quartz container.

Isobutyl alcohol according to GOST 6016−77.

Tin dichloride in NTD, solution A, is prepared as follows: 10 g SnCl· HO was dissolved with heating in 25 cmof hydrochloric acid.

Solution B is prepared as follows: to 1 cmsolution And add 200 cm1 n sulfuric acid solution and stirred. Solution B is unfit for use during the day.

Acetone according to GOST 2603−79.

Other reagents and equipment, see PP. 2.1.2 and

2.2.2.

3.1; 3.2. (Changed edition, Rev. N 1).

3.3. Analysis

3.3.1. 0.5 g of steel (in mass fraction of phosphorus from 0.002 to 0.12%) or 0.25 g (with a mass fraction of phosphorus from 0.12 to 0.25%) was placed in a beaker with a capacity of 200−250 cm, add 10 cmof nitric acid, 30 cmof hydrochloric acid, cover with watch glass and dissolve the sample when heated.

For the mass concentration of arsenic more than 0,003% and tungsten is less than 3% of arsenic is removed by Stripping. To do this, the solution is evaporated to dryness, add 10 cmof hydrochloric acid and again evaporated to dryness. This operation is repeated again. The dry residue was dissolved with heating in 15 cmof hydrochloric acid, poured 10 cmof a solution of ammonium bromide and the solution is evaporated to wet condition salts, then add 10 cmof hydrochloric acid and again evaporated to wet condition salts. This operation is repeated again. Then add 15 cmof hydrochloric acid diluted 1:3 and heated to dissolve the salts.

To the obtained solution add 40−50 cmof perchloric acid, heat the solution before its release vapour and 5 min.

In that case, if the steel contains chromium, it is distilled in the form of chloride promila, to do this, after complete oxidation of chromium chloric acid remove watch glass and added dropwise hydrochloric acid to stop the allocation of brown fumes of chloride gromila. A glass cover glass and heat the solution until complete oxidation of chromium. The operation of distillation chloride gromila repeat until its full removal.

The solution is slightly cooled, add to it 2−3 cmof a saturated solution of sodium semitecolo, 10−15 cmof water and boil for 5−7 minutes, then add 15 cmof a solution of ammonium fluoride and heated for 5 min.

If the solution is turbid, it is filtered in a volumetric flask with a capacity of 100 cmthrough a filter «white ribbon» with the addition of a small amount of ashless paper pulp. The glass and the filter cake was washed 5−6 times with hot water.

The solution was cooled, made up to the mark with water and traveling.

sivut.

3.3.2. 10 cmof the resulting solution (with mass fraction of phosphorus from 0.002 to 0.06%) or 5 cm(when the mass fraction of phosphorus from 0.06% to 0.25%) was placed in a separating funnel with a capacity of 200 cm.

The solution was diluted to 50 cmof perchloric acid, diluted 1:50, add 10 cmsulphuric acid solution of molybdate of ammonium, 20 cmisobutyl alcohol and shake for 1 min.

Give separated layers, aqueous layer is discarded, the alcohol layer was added 15 cmof a solution of tin chloride and shake for 1 min to Give separated layers, aqueous layer discarded.

The organic layer is poured into a dry volumetric flask with a capacity of 50 cm, rinse the separating funnel with acetone, adding it to the solution in a volumetric flask, add acetone to the mark and mix.

Measure the optical density of the solution on the spectrophotometer at a wavelength of 725 nm or photocolorimeter with a red filter (light transmission region of 620−640 nm) in a cuvette with a layer thickness of 20 mm, a solution of comparison is the extract aliquote the second part, to which is added all of the above reagents, except molybdate of ammonium.

The mass of phosphorus (in g), as amended by the reference experiment for the calibration chart find

.

3.3.1; 3.3.2. (Changed edition, Rev. N 1).

3.3.3. Construction of calibration curve

In a separating funnel with a capacity of 200 cmwith a label applied at 50 cm, is placed 0,25; 0,5; 1; 1,5; 2; 2,5 and 3 cmstandard solution B of single potassium phosphate, which corresponds to 2,5; 5; 10; 15; 20; 25 and 30 mg of phosphorus.

Add 1.5 cmof a solution of ammonium fluoride, made up to 50 cmof perchloric acid, diluted 1:50, then add 10 cmsulphuric acid solution of ammonium molybdate, 20 cmisobutyl alcohol and shake for 1 min.

Give separated layers, aqueous layer discarded. To the alcoholic layer was added 15 cmof a solution of tin chloride and shake for 1 min to Give separated layers, aqueous layer discarded.

The organic layer is poured into a dry volumetric flask with a capacity of 50 cm, rinse the separatory funnel with acetone, adding it to the solution in a volumetric flask, add acetone to the mark and mix.

Optical density of the solution measured on a spectrophotometer at a wavelength of 725 nm or photoelectrocolorimeter, the interval of light absorption 620−640 nm in a cuvette with a layer thickness of 20 mm. as a solution of comparison is the extract of the solution in the reference experiment.

On the found values of optical density according to the revision control experience to build a calibration curve.

(Changed edition, Rev. N

1).

3.4. Processing of the results

3.4.1. Mass fraction of phosphorus () in percent is calculated by the formula

,

where is the mass of phosphorus was found in the calibration schedule, mcg;

 — weight of steel taken for the measurement of ICG.

(Changed edition, Rev. N 1).

3.4.2. The allowable differences specified in clause 2.5.2.

ANNEX 1 (recommended). A VISUAL COLORIMETRIC METHOD FOR THE DETERMINATION OF PHOSPHORUS (0,002−0,25%)

ANNEX 1
Recommended

1. General requirements

1.1. General requirements for methods of analysis GOST 20560−81.

2. Method for the determination of phosphorus in steels with a mass fraction of tungsten up to 5%, chromium 5% Nickel to 5%

2.1. The essence of the method

The method is based on the reaction of formation of the molybdophosphoric yellow heteroalicyclic H/P (MoO)/p·HO and extracted with ether and reduced with tin chloride to complex compound, colored blue. The intensity of the color of the ether layer compared to the scale of standard solutions. Blue color of the complex is stable for 3−5 min.

Trivalent phosphorus of the pre-oxidized to pentavalent with potassium permanganate.

The interfering influence of vanadium can be eliminated by addition of bivalent iron. Interfere with the determination of titanium, zirconium and niobium.

Interfering with the action of arsenic can be eliminated by Stripping it in the form of trichloride arsenic.

2.2. Reagents

Copper nitrate according to normative-technical documentation.

Nitric acid GOST 4461−77 diluted 1:9 and 1:13.

Cobalt grade K0 GOST 123−78.

Cobalt nitrate according to GOST 4528−78.

Ammonium molybdate according to GOST 3765−78, solution; is prepared as follows: 75 g of ammonium molybdate was dissolved with heating in 500 cmof water, the solution was cooled and poured with stirring into 500 cmof nitric acid, diluted 1:1. The solution was incubated for 3−5 days and filtered through a filter «white ribbon». Before administration, the solution is diluted with water in ratio of 1:1. In the presence of a yellow precipitate a solution unfit for use.

Tin dichloride in NTD, the solution is prepared as follows: 2 g of SnCl·2HO was dissolved with heating in 30 cmof hydrochloric acid, the solution is cooled, add to it 70 cmof water and stirred.

The diethyl ether.

Carbonyl iron according to normative-technical documentation (99.9% of total iron).

Iron ferrous sulfate according to GOST 4148−78, a solution with a mass concentration of 300 g/lin sulphuric acid, diluted 1:50.

Nitric acid GOST 4461−77.

Hydrochloric acid by the GOST 3118−77.

Potassium permanganate according to GOST 20490−75, a solution with a mass concentration of 40 g/DM.

Sodium atomistically according to GOST 4197−74, a solution with a mass concentration of 50 g/DM.

Ammonium bromide according to GOST 19275−73, a solution with a mass concentration of 100 g/

DM.

2.3. Preparation for assay

2.3.1. Preparation of a scale of standard solutions

2.3.1.1. Test tubes for color standard and the analyzed solutions must be made from the same glass and have the entire height of the same diameter.

It is recommended to use tubes with an internal diameter of approximately 8 mm, as required accuracy of analysis results is achieved by comparison is quite weak colors. The height of the vials for standard solutions should be 220 mm for the analyzed solutions of 160 mm.

Selection of tubes of the same diameter produced by perelivania in a clean, dry test tube pipette equal amounts of water. The tubes in which the water levels will be located at the same height, can be considered as having almost the same diameters.

For the preparation of standard color solutions use solutions of copper nitrate, of cobalt nitrate, iron nitrate and nitric acid, diluted 1: 13.

The solution of nitrate of copper; prepared as follows: 100 g of Cu (NO)·6HO dissolved in 95 cmof nitric acid, diluted 1: 9. The solution was filtered.

The solution of nitrate of cobalt; prepared as follows: 10 g of cobalt grade K0 is dissolved by heating in 100 cmof nitric acid, diluted 1:1, the solution was evaporated to 70−80 cm, cooled, filtered in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix. 10 cmsolution is transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Note. Instead of the metal cobalt nitrate solution of cobalt can be prepared from salts of Co (NO)· 6HO.


The solution of nitrate of iron: 4,971 grams of iron carbonyl is placed in a beaker with a capacity of 400 cm, gradually pour the 50−60 cmof nitric acid (1:4) and dissolve when heated. The solution was filtered through a filter of medium density in a volumetric flask with a capacity of 100 cm. The beaker and the filter washed with hot water. The solution was cooled, made up to the mark with water and mix.

81,2 cm mixedsolution of copper nitrate, 97,0 cmof solution of nitrate of cobalt and 21.8 cmsolution of iron nitrate (solution A). The resulting solution is diluted nitric acid, diluted 1:13, as indicated in the table. 1.

Table 1

After filling colored standard solutions vials tightly closed with rubber stoppers and placed in the tripod socket, with milk glass. The scale should be checked and adjusted by adding to each tube drop by drop those solutions, which were prepared simulating the solution. The solutions were added until, until the color mimics of the solution in each test tube will not be similar to color of the ether layer over a sample solution of the corresponding standard sample. Use standard samples of carbon and low-alloy steel.

The ratio of the amount of the solution and nitric acid, diluted 1: 13, used in the preparation of the scale of standard solutions are given in table. 1.

Mass fraction of phosphorus (see table. 1) corresponds to the sample standard sample of 0.2 g and diluted to 50 cm.

For the preparation of solutions of standard samples of steel used for test and adjustment of the scale of standard solutions of 0.2 g of steel placed in a beaker with a capacity of 100 cmand dissolved by heating in 10 cmof nitric acid, diluted 1:1. In the boiling solution is added a solution of potassium permanganate prior to the allocation of brown precipitate of manganese dioxide. Add dropwise a solution of sodium azotistykh for dissolution of manganese dioxide and boil to remove oxides of nitrogen. The solution was cooled, transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix.

2 cmresulting solution was placed in a vial for colorimetrically.

2.3.1.2. To the solution are added 1 cmof molybdate ammonium solution, close the test tube with a stopper and shake the contents. Add from a burette 2 cmof ether, close vial with stopper and again 2−3 times shaken its contents. Allowed to settle the foam, add 8−10 drops of solution of chloride of tin, mainly in the center of the ethereal layer.

After addition of a solution of chloride of tin content vial should not be shaken, as the blue coloration of the ether layer thus partially weakening.

After 5−10 min add 3−4 drops of solution of chloride of tin. Close the test tube with a stopper and compare the intensity of color of the ethereal layer with a scale of standard solutions. The color of the ether layer stable over 3−5 min after completion of addition of solution of chloride of tin.

In the solution in the reference experiment on the weight of phosphorus in the reagents practically must not contain phosphorus.

In those cases, when to check for this standard solution it is difficult to find the corresponding mass fraction of phosphorus of a standard steel sample, you can change the linkage of a standard sample or use of a combined linkage of the two standard samples. The mass modified or combined hitch needs to remain in the range of 0,16−0,24 g in order to maintain a relative constant amount of ferric iron ions in solution.

2.4. Analysis

2.4.1. 0.2 g of steel (in mass fraction of phosphorus from 0.002 to 0.07%) or 0.1 g (for the mass concentration of phosphorus than 0.07%) were placed in a glass with a capacity of 400 cm, flow 10 cmof nitric acid, 30 cmof hydrochloric acid and dissolved by heating.

The solution is diluted with hot water up to 200−250 cm, heated to boiling and allowed to settle upset tungsten (partly silicic) acid for 30 min.

The precipitate was filtered off on filter «white ribbon» with the addition of a small amount of ashless paper pulp, collecting the filtrate in a beaker with a capacity of 500 cm. The filter cake is washed 6−8 times with hot nitric acid, diluted 1:100. Filter the precipitate tungsten acid drop. The solution was evaporated to wet condition salts.

Pour 5−7 cmof nitric acid and evaporate the solution until a state of moist salts. The addition of nitric acid and evaporating the solution to dryness again.

Pour 5 cmof nitric acid, 10−15 cmof water and heated to dissolve the salts, then the solution was heated to reflux, added dropwise a solution of potassium permanganate before rolling the brown precipitate of manganese dioxide (1−2 cm) and boil for 2−3 min. To the boiling solution poured dropwise a 5% solution of sodium attestatio to dissolve the residue. The solution was boiled for a few minutes to remove the oxides of nitrogen and cooled.

(Modified taccia, Rev. N

1).

2.4.2. When the mass fraction of arsenic in the analyzed sample is more than 10% of the mass fraction of phosphorus, or if the mass fraction of arsenic is unknown, the latter is removed by Stripping in the form of trichloride arsenic. To do this, the solution is evaporated to dryness. To the dry residue poured 10 cmof hydrochloric acid and again evaporated to dryness. This operation is repeated again. The dry residue was dissolved with heating in 15 cmof hydrochloric acid, poured 10 cmof a solution of ammonium bromide and the solution is evaporated to wet condition salts, then pour 10 cmof hydrochloric acid and again evaporate the solution until a state of moist salts. Surging hydrochloric acid and evaporation of the solution to the state of moist salts again. Pour 5 cmof nitric acid, 5−10 cmof water and dissolved salts when heated.

The solution was transferred to a volumetric flask with a capacity of 50 cm(with a mass fraction of phosphorus from 0.002 to 0.14%) or 100 cm(with a mass fraction of phosphorus from 0.14 to 0.25%). In a flask with a capacity of 100 cmadd 5 cmof nitric acid, the solution was cooled, made up to the mark with water and mix.

In the middle of colorimetrically placed aliquot part of the analyzed solution in accordance with the table. 2.

If the steel contains vanadium, the solution in the test tube add 0.5 cmof a solution of sulphate ferrous iron. The vial is closed with a rubber stopper and shaken its contents 2−3 times.

Analysis done visual colorimetric method, as described in section 2.3.1.2.

Table 2

3. Method for the determination of phosphorus in chromium and chromium-Nickel steels

3.1. The essence of the method

The method is based on dissolving the steel in a mixture of nitric and hydrochloric acids. Chrome is oxidized to hexavalent in the environment neccersarily nitrate to ammonia. For complete oxidation of trivalent phosphorus to pentavalent apply potassium permanganate.

Phosphorus is precipitated with ferric hydroxide collector in the ammonia environment. The precipitate was filtered off and dissolved in nitric acid.

Analysis done visual colorimetric method.

3.2. Reagents

Ammonium neccersarily according to GOST 20478−75, a solution with a mass concentration of 250 g/DM.

Ammonia water according to GOST 3760−79.

The rest of the reagent according to claim 2.2.

3.3. Analysis

0.2 g of steel (in mass fraction of phosphorus from 0.002 to 0.07%) or 0.1 g (for mass fraction of phosphorus from 0.07 to 0.25%) was placed in a beaker with a capacity of 400 cm, add 15 cmof nitric acid, 10 cmof hydrochloric acid and dissolved by heating. The solution was evaporated to wet condition salts, add 5−10 cmof nitric acid and evaporate the contents of the Cup to the state of moist salts.

This operation is repeated again. Pour 5 cmof nitric acid, heated, diluted the solution with water to a volume of 80−100 cmand heated to boiling, then pour 20 cmof the solution naternicola ammonia and heat the solution until complete oxidation to hexavalent chromium. To the boiling solution add 1−2 cmof solution of potassium permanganate and boiled until precipitation of manganese dioxide. Pour a solution of ammonia until the full allocation of iron hydroxide and about 0.5 g of ammonium naternicola. The contents of the glass boil for 1−2 min, allow the residue to soak for 3−5 min and filter it to the filter «white ribbon». The glass and the filter cake was washed 5−6 times with a hot solution of ammonia, diluted 1:100. Iron hydroxide washed from the filter with water into the glass, which conducted the deposition. The filter was washed with 40 cmof hot nitric acid diluted 1:1 with the addition of a few drops of solution of sodium and attestatio 5−6 times with hot water. Wash liquid collected in the beaker with the sediment.

The contents of the beaker is heated to dissolve the residue and evaporate the solution to a volume of 8−10 cm.

The analysis continues as described in section 2.4.2.

4. Method for the determination of phosphorus in steels with a mass fraction of tungsten up to 5%, titanium up to 1.5%, niobium, chromium, Nickel and vanadium, up to 1.5%

4.1. The essence of the method

The method is based on dissolving steel sample in a mixture of nitric and hydrochloric acids. Oxidized to hexavalent chromium by heating with perchloric acid. At the same trivalent phosphorus is oxidized to pentavalent.

Chrome separated from the phosphorus Stripping chloride gromila. Interfering with the action of tungsten, titanium, zirconium and niobium can be eliminated by addition of ammonium byflorida.

Analysis done visual colorimetric method.

4.2. Reagents

Acid chloride according to normative-technical documentation, with a density of 1.50 g/cm.

Ammonium fluoride acidic (before ammonium) according to GOST 9546−75.

The rest of the reagent according to claim 2.2.

4.3. Analysis

0.2 g of steel (in mass fraction of phosphorus from 0.002 to 0.07%) or 0.1 g (for mass fraction of phosphorus from 0.07 to 0.25%) was placed in a beaker with a capacity of 250 cm, flow 10 cmof nitric acid, 30 cmof hydrochloric acid, cover the beaker watch glass and dissolve the sample when heated.

When the mass fraction of arsenic in the analyzed sample is more than 10% by weight of phosphorus, or if the mass fraction of arsenic is unknown, it is removed by Stripping in the form of trichloride arsenic. To do this, the solution is evaporated to dryness. To the dry residue poured 10 cmof hydrochloric acid and evaporated to dryness. The dry residue was dissolved with heating in 15 cmof hydrochloric acid, poured 10 cmof a solution of ammonium bromide and the solution is evaporated to wet condition salts, then pour 10 cmof hydrochloric acid and again evaporated to wet condition salts. Surging hydrochloric acid and evaporation of the solution to the state of moist salts again.

The solution is poured 10 cmof perchloric acid and heat the contents of the glass to the complete oxidation of chromium. Remove the watch glass and carefully poured along the walls of the Cup 5 cmof hydrochloric acid to stop the allocation of brown fumes of chloride gromila. Glass again cover glass and heat the solution until complete oxidation of chromium. The operation of distillation chloride gromila be repeated several times to remove the main mass of chromium.

Add 10 cmof nitric acid. The solution is heated and added (without stopping of heating) with stirring 0.4 g of ammonium byflorida, weighted with the error not more than 0,01 g. After dissolving the precipitate, containing titanium, zirconium and niobium, the solution is transferred to a volumetric flask with a capacity of 100 cm, cooled, made up to the mark with water and mix. Precipitate tungsten acid is allowed to settle for 15 min.

In the middle of colorimetrically placed aliquot part of the analyzed solution in accordance with the table. 3.

If the steel contains vanadium, the solution in the test tube add 0.5 cmof a solution of sulphate ferrous iron. The vial is closed with a rubber stopper and shaken its contents 2−3 times.

Analysis done visual colorimetric method, as described in section 2.3.1.2.

Table 3

5. Processing of the results

5.1. Mass fraction of phosphorus in percent adjusted in the reference experiment, find on the scale of standard solutions.

Depending on the mass of sample, volume of the volumetric flask and aliquoting part of the solution was found in the scale multiplied by the appropriate factor as specified in table. 4.

Table 4

5.2. The allowable divergence between the extreme results of three parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 5.

Table 5

APPENDIX 2 (recommended). 1. Titrimetric method for the determination of phosphorus (0,02−0,25%)

ANNEX 2
Recommended

1.1. The essence of the method

The method is based on the precipitation of phosphorus in the form of phosphoromolybdate ammonium (NH)RO·12MoO·2HO. the Precipitate is dissolved in a titrated solution of alkali, excess of which octarepeat nitric acid.

The use of nitric acid to dissolve the sample prevents the volatilization of phosphorus in the form of phosphine gas.

Trivalent phosphorus is oxidized to pentavalent previously.

Interfering with the action of arsenic can be eliminated by Stripping it in the form of trichloride arsenic.

The method is not applicable for the analysis of steels containing titanium, zirconium, niobium and 5% tungsten.

1.2. Reagents

Nitric acid GOST 4461−77 and diluted 1:2, 1:100.

Hydrochloric acid by the GOST 3118−77.

Potassium permanganate according to GOST 20490−75, a solution with a mass concentration of 40 g/DM.

Sodium atomistically according to GOST 4197−74, a solution with a mass concentration of 56 g/DM.

Ammonia, aqueous solution according to GOST 3760−79.

Ammonium molybdate according to GOST 3765−78.

Molybdenum liquid; is prepared by mixing two solution of 36 g of ammonium molybdate dissolved in 30 cmof ammonia solution and 50 cmof water; 115 cmof ammonia solution carefully poured in 575 cmof nitric acid, diluted 1:1, and add 230 cmof water. The resulting solutions are cooled and mixed, gently infusing the first solution in the second with strong shaking to produced white turbidity disappeared. Thus it is necessary to periodically cool the solution, avoiding its heating. The solution was then allowed to stand for 48 hours Before use it was filtered.

Ethyl alcohol GOST 18300−87.

Ammonium radamisty, solution mass concentration of 100 g/DM.

Potassium nitrate according to GOST 4217−73, a solution with a mass concentration of 10 g/DM.

Phenolphthalein according to NTD, a solution with a mass concentration of 10 g/DM; prepared as follows: 1 g of phenolphthalein is dissolved in 60 cmof ethanol and mixed with 40 cmof water.

Water is neutral; are prepared as follows: to 1 DMof water, from which previously removed carbon dioxide by boiling for 2−3 h, poured 5cmof solution of phenolphthalein and the amount of titrated solution of sodium hydroxide to water is a persistent pink color. Then to the solution was added dropwise titrated a solution of nitric acid until the disappearance of color. 50 cmneutralized water should be painted in pink color from the addition of one drop of the titrated sodium hydroxide solution.

Barium hydroxide according to GOST 4107−78.

The lime soda.

Sodium hydroxide (caustic soda) according to GOST 4328−77, titrated solution; prepared as follows: 33 g of sodium hydroxide dissolved in 10 DMof water, from which previously removed carbon dioxide by boiling for 2−3 h. the solution was poured 3−5 cmsolution with a mass concentration of 10 g/DMbarium hydroxide and allowed to stand for 2−3 days until the precipitate of barium dioxide will be defended fully. The solution is stored in bottles closed with a rubber stopper with two holes: one of them is inserted into the absorber with soda lime, the other a siphon tube with a tap, not reaching to the bottom of the bottle is 0.5 cm, with curved end up.

Sivunirmut clear solution into another bottle and store as above.

Nitric acid GOST 4461−77, titrated solution; prepared as follows: 50 cmof nitric acid was placed in a bottle and diluted to a volume of 10 DMof water, from which previously removed carbon dioxide by boiling for 2−3 h. 1 cmof a solution of nitric acid must make up about 1 cmof the titrated sodium hydroxide solution. The solution is stored in bottles closed with a rubber stopper with two holes: one of them is inserted into the absorber with soda lime, the other siphon tube (with stopcock), not reaching to the bottom of the bottles to 0.5 cm.

The ratio of titrated solution of sodium hydroxide and nitric acid are set as follows: in a conical flask with a capacity of 300 cmis poured from a burette 25 cmof sodium hydroxide, add 25 cmneutral water and titrated with nitric acid until the disappearance of the red color.

The ratio between solutions of sodium hydroxide and nitric acid () is calculated by the formula

,

where is the volume of sodium hydroxide solution taken for titration, cm;

 — the volume of nitric acid consumed for titration, sm.

Titer of sodium hydroxide solution installed on the hitch of a standard sample of steel of known phosphorus content, similar in composition to the test sample, is carried out through all stages of analysis, as specified in clause 1.3.1.

Titer of sodium hydroxide (T), expressed in grams of phosphorus, calculated by the formula

,

where is the weight of a standard steel sample, g;

 — mass fraction of phosphorus in the standard sample, %;

 — the volume of sodium hydroxide taken to dissolve the precipitate phosphoromolybdate ammonium, cm;

 — the volume of nitric acid consumed in the titration of sodium hydroxide solution in the analysis of a standard sample, ml;

 — the ratio of titrated solutions of sodium hydroxide and nitric acid.

1.3. Analysis

1.3.1. Determination of phosphorus in steels containing tungsten and with a mass fraction of chromium of less than 5%

1.3.1.1. 2 g of steel placed in a beaker with a capacity of 300−400 cm, 70 cm, addnitric acid diluted 1:2, and dissolved under heating.

If the linkage is not soluble in nitric acid, it add 10 cmof hydrochloric acid, heat until dissolved and the solution is evaporated to a state of moist salts. Add 10 cmof nitric acid and again evaporate the solution until a state of moist salts, then add 10 cmof nitric acid, 15−20 cmof water and heated to dissolve the salts.

1.3.1.2. The precipitate of silicic acid is filtered off, the filter «white ribbon» with the addition of a small amount of ashless paper pulp, collecting the filtrate in a conical flask with a capacity of 300 cm. The filter cake is washed 6−8 times with hot nitric acid, diluted 1:100. Filter the precipitate of silicic acid is discarded.

Note. If the mass fraction of silicon in the analyzed sample exceeds 1.5%, the filter with the precipitate of silicic acid is placed in a platinum crucible, dried, incinerated and calcined at 800−900°C. the Precipitate is moistened with 2−3 drops of water, add 8−10 drops of nitric acid, 3−5 cmhydrofluoric acid and cautiously evaporate the contents of the crucible to dryness. The residue is fused in a crucible with 1−2 g of sodium carbonate at 1000−1100°C. the Melt leached with water while boiling, the crucible is washed with water, and add nitric acid diluted 1:1 prior to decomposition of carbonates (the cessation of foaming). The resulting solution was attached to the main filtrate.

To the boiling filtrate add 5−10 cmof solution with mass concentration 40 g/lpotassium permanganate and boil until a drop of brown precipitate of manganese dioxide. Not stopping the heat, poured drop by drop a solution with a mass concentration of 50 g/DMazotistykh sodium until complete dissolution of the precipitate and boil to remove oxides of nitrogen.

When the mass fraction of arsenic in the analyzed steel more than 10% by weight of phosphorus, or, if the arsenic content is unknown, the latter is removed by Stripping in the form of trichloride arsenic. To this end, the solution was evaporated to dryness, the dry residue add 10 cmof hydrochloric acid and again evaporate the solution to dryness. This operation is repeated two more times for the decomposition of nitrates. The dry residue was dissolved with heating in 15 cmof hydrochloric acid, poured 10 cmof a solution with a mass concentration of 100 g/DMammonium bromide and evaporated to wet condition salts. Evaporation of the solution to the state of moist salts again, adding before steaming 10 cmof hydrochloric acid, then add 10 cmof nitric acid and evaporated to wet condition salts. The addition of nitric acid and evaporation to the state of moist salts again. Then add 10 cmof nitric acid, 10−15 cmof water and heated to dissolve the salts.

The solution is cooled, add to it ammonia solution prior to the precipitation of iron hydroxide, which is dissolved in nitric acid, priliva her dropwise. Add another 5 cmof nitric acid.

The solution is heated to 50−60°C, add 50 cmmolybdenum liquid and shaken for a few minutes before rolling phosphoromolybdate yellow precipitate of ammonium. Sediment is allowed to settle for 2−3 h.

The precipitate was filtered off on the filter «blue ribbon» with the addition of a small amount of ashless paper pulp. Flask in which to carry out the deposition, and the filter cake washed 6−7 times with nitric acid, diluted 1:100, for the removal of iron. To verify the completeness of the laundering of iron sludge from 0.5−1 cmflowing wash liquid is collected in a test tube and pour 3−5 drops of solution with a mass concentration of 100 g/DMRodenstock ammonium. The liquid in the vial should remain colorless.

Precipitate was washed 5−7 times with a solution of potassium nitrate to remove free nitric acid. To verify the completeness of the laundering of sediment 8−10 drops flowing wash liquid is collected in a test tube, poured two drops of the solution with mass concentration 10 g/DMof phenolphthalein and one drop of the titrated solution of sodium hydroxide. If the precipitate is washed, the liquid in the vial should be painted in red.

The filtrate is discarded. The filter with precipitate was placed in a flask in which to carry out the deposition, poured 25 cmneutral water, five drops of solution of phenolphthalein, break the filter glass rod into small pieces and stirred the contents of the flask. Pour the titrated solution of sodium hydroxide to the appearance of red coloring and stirred the contents of the flask until complete dissolution of the precipitate. If phosphoromolybdate ammonium precipitate is not dissolved, poured some more of the titrated sodium hydroxide solution (after dissolution of the precipitate the solution should have a pink color). Add another 3−5 cmof sodium hydroxide solution, washed walls neutral with water and titrate the excess of alkali titrated with a solution of nitric acid until the disappearance of the red color. The filtrate with the sediment control experience, poured 25 cmneutral water, 25 cmtitrated solution of sodium hydroxide after dissolution of the precipitate octarepeat the excess of alkali titrated with a solution of nitric acid,

AK described above.

1.3.2. Determination of phosphorus in steels with a mass fraction of tungsten of at least 5% chromium and less than 5%

2 g of steel placed in a beaker with a capacity of 300−400 cm, 60 cm pournitric acid, diluted 1:2, 15 cmof hydrochloric acid and dissolved with moderate heating.

The solution was evaporated to a volume of 20−30 cm, dilute with hot water to a volume of 250−300 cm, heated to boiling and allowed to settle precipitate tungsten acid for 2 hours.

The precipitate was filtered off on the filter «blue ribbon» containing a small amount of ashless paper pulp. The filtrate collected in a beaker with a capacity of 600 cm. The glass and the filter cake was washed 8−10 times with hot nitric acid, diluted 1:100. The precipitate is discarded.

The solution was evaporated to wet condition salts, add 10 cmof nitric acid, 30−40 cmof water and heated to dissolve the salts.

Further analysis are as described in section 1.3.1.

2.

1.4. Processing of the results

1.4.1. Mass fraction of phosphorus () in percent is calculated by the formula

,

where is the volume of sodium hydroxide taken to dissolve the precipitate phosphoromolybdate ammonium, cm;

 — the volume of nitric acid consumed in the titration of excess sodium hydroxide in the analysis of steel, cm;

 — the ratio of titrated solutions of sodium hydroxide and nitric acid;

the titer of the sodium hydroxide solution, expressed in grams of phosphorus;

 — weight of charge, g

.

1.4.2. The allowable divergence between the extreme results of three parallel measurements at a confidence level = 0.95 does not exceed the values given in the table.