GOST 29117-91

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  ГОСТ 29117-91

GOST 29117−91 Steel alloyed and high alloy. Methods for determination of bismuth

GOST 29117−91

Group B39

INTERSTATE STANDARD

STEEL ALLOYED AND HIGH-ALLOYED

Methods for determination of bismuth

Alloyed and high-alloyed steels. Methods of bismuth determination

ISS 77.080.20
OKP 0809

Date of introduction 1993−01−01

INFORMATION DATA

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

2. APPROVED AND promulgated by the Decree of Committee of standardization and Metrology of the USSR dated 21.10.91 N 1631

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. REPRINTING. May 2004


This standard specifies the photometric (in mass fractions of from 0.0005% to 0.01%) and flameless atomic absorption (in mass fractions of from 0.0001% to 0.01%) and Stripping voltammetric (in mass fractions of from 0.0001% to 0.005%) and polarographic (in mass fractions of from 0.001% to 0.01%) methods for determination of bismuth in the alloy and high-alloy steels.

1. GENERAL REQUIREMENTS

General requirements for methods of analysis GOST 28473.

2. PHOTOMETRIC METHOD

2.1. The essence of the method

The method is based on the formation of pink-colored complex compound of bismuth with selenology orange in nitric acid concentration of 0.1 mol/DMand the measurement of its optical density in the region of light transmission with an absorption maximum at a wavelength of 540 nm.

Bismuth is pre-separated from the accompanying elements of the steel by precipitation as a sulfide by thioacetamide in ammoniacal solution in the presence of the collector of sulphide of copper and tartaric acid as complexing agents or by the method of ion exchange chromatography.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter with all accessories for measurements in the visible region of the spectrum.

a pH meter.

Thermometer with scale up to 150 °C.

Ion exchange column diameter of 1.2−1.5 cm, 30−40 cm high, filled with the anion exchanger an-31, AV-17−8 and AV-17−8чС in -form with a layer height of 15 cm.

Anion exchange resin an-31 according to GOST 20301.

Preparation of anion analysis: 200 g of anion exchange resin is filled at least fivefold volume of a saturated solution of sodium chloride and allowed to swell for 24 h.

To separate the resin fraction with a grain size of less than 0.4 mm, the slurry of the resin in a solution of sodium chloride was poured onto the sieve N 063 according to GOST 6613 and washed with water, collecting the past through a sieve fraction of the anion exchanger with water in a vessel with a capacity of 2−3 DM. Remaining on the sieve resin cast. Liquid over the fraction of the anion exchanger, passed through the sieve was decanted and the resin washed with method of decanting the hydrochloric acid concentration at the beginning of 3 mol/DM, and then 0.5 mol/DMto complete removal of Fe (III) (sample with romanisti potassium). The anion exchanger was washed with 10-fold amount of water, then pour to 48 hours with a solution of sodium hydroxide. Further, the anion exchanger is washed with water to neutral reaction on the universal indicator and stored under water in a glass jar with a glass stopper. Before beginning work in the lower part of the chromatographic column is placed a tampon of PVC filaments or of glass wool, previously boiled in hydrochloric acid (1:1) and washed with water. Ion-exchange column filled with anion exchange resin for a layer height of 15 cm and then with water at its height. The layer of the anion exchanger should be smooth, without air bubbles. For transferring the resin to form through her missing 100−150 cmof hydrochloric acid concentration of 3 mol/DMat a speed of 1 cm/min.

Anion exchange resin AV-17−8 and AV-17−8чС according to GOST 20301.

Preparation of anion analysis: 200 cmcommodity anion exchanger AV-17−8 and AV-17−8чС (produced in the form of a slurry in water) was washed twice with water by decantation method. To separate the resin fraction with a grain size of less than 0.6 mm, the slurry of resin in water poured into a sieve N 063 according to GOST 6613 and washed with water, collecting the past through a sieve fraction of the anion exchanger with water in a vessel with a capacity of 2−3 DM. Remaining on the sieve resin cast. The fraction of anion resin that passed through the sieve, is subjected to the preparation of the analysis, as the resin an-31.

Hydrochloric acid according to GOST 3118 or GOST 14261, diluted 1:1, and the solutions with concentration of 3 mol/land 0.5 mol/DM.

Nitric acid according to GOST 4461 or GOST 11125, diluted 1:1, 1:15, 1:500, and solutions of concentration 1 mol/land 0.1 mol/DM.

A mixture of hydrochloric and nitric acids: the 150 cmof hydrochloric acid add 50 cmof nitric acid, 200 cmof water and stirred. The mixture is prepared immediately before use.

Ascorbic acid, a solution of concentration 100 g/l, freshly prepared.

Tartaric acid according to GOST 5817, solutions of concentration 500 g/land 100 g/DM.

Ammonia water according to GOST 3760 or GOST 24147 and diluted 1:200.

The thioacetamide solution concentration of 20 g/DM.

Selenology orange solution with a concentration of 1 g/lin nitric acid concentration of 0.1 mol/DM.

Sodium chloride according to GOST 4233, saturated solution.

Sodium hydroxide according to GOST 4328, solution concentration of 50 g/DM.

Potassium rodanistye according to GOST 4139, solution concentration of 50 g/DM.

Copper grade M00b according to the GOST 859.

Copper nitrate solution concentration of 0.01 g/cm: 1 g of copper is dissolved by heating in 15−20 cmof nitric acid (1:1). The solution was boiled to remove oxides of nitrogen, cooled, diluted with water to 100 cmand mixed.

Radio engineering carbonyl iron brand PS according to GOST 13610.

Universal indicator paper pH 1−10.

Vi00 bismuth grades according to GOST 10928, brands Ви000 and Ви0000 on the other 48−6-11*.
________________
* The one mentioned here, are not given. For additional information, please refer to the link. — Note the manufacturer’s database.

Standard solutions of bismuth.

Solution a: 0.1 g of bismuth was dissolved with heating in 30 cmof nitric acid, boil the solution to remove oxides of nitrogen, cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g of bismuth.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, add 10 cmof nitric acid, made up to the mark with water and mix.

1 cmstandard solution B has the 0.00001 g of bismuth.

2.3. Analysis

2.3.1. Preparation of test solution

2.3.1.1. For steels containing tungsten, molybdenum, niobium

The weight of steel weight of 1 g (in mass fractions of bismuth from 0.0005% to 0.002%) or 0.5 g (at a mass fraction of bismuth from 0.002% to 0.01%) were placed in a glass (or flask) with a capacity of 250−300 cm, pour 15−20 cmof hydrochloric acid and 5 cmof nitric acid, cover with watch glass and dissolve the sample when heated.

The solution was evaporated to a volume of approximately 10 cmadd 30 cmof water, 20−30 cmof a solution of tartaric acid concentration of 500 g/land heated for 10 min. the Solution was cooled, add 20−25 cmammonia to pH 8−10 by universal indicator, and again heated for 10 min to dissolve the precipitated tungsten and molybdenum acids. Add 1 cmof solution of nitrate of copper, set pH 7.5 by adding hydrochloric acid (1:1) or ammonia, using a pH meter.

The solution is diluted with water to 150 cm, heated to 85 °C — 90 °C, pour 10 cmof a solution of thioacetamide, incubated 10 min at the same temperature and again poured 10 cmof a solution of thioacetamide. Leave the solution to precipitate for 2 h at 40 °C — 50 °C.

Then the solution with precipitate was cooled to room temperature, filtered off the precipitate of sulfides of two medium density filter (white ribbon), washed 7−8 times with cold water, the filtrate discarded. The filter cake is dissolved in 30−40 cm(chunks 10 cm) of a hot mixture of hydrochloric and nitric acids and the filter was washed 2−3 times with hot nitric acid (1:500), collecting the filtrate and washings in a beaker, in which was conducted the deposition. The filter is discarded.

2.3.1.2. For steels containing tungsten, molybdenum, niobium

The weight of steel weight of 1 g (in mass fractions of bismuth from 0.0005% to 0.002%) or 0.5 g (at a mass fraction of bismuth from 0.002% to 0.01%) were placed in a glass (or flask) with a capacity of 250−300 cm, pour 15−20 cmof hydrochloric acid and 5 cmof nitric acid, cover the beaker (or flask) watch glass and dissolve the sample when heated. The solution was evaporated to wet salts. Salt dissolved in 5−7 cmof hydrochloric acid and again evaporated to moist salts. This operation is repeated. Salt is dissolved in 40 cmof hydrochloric acid concentration of 3 mol/DMby heating until boiling. The precipitate of silicic acid is filtered out by two medium density filter (white ribbon) and washed 3−4 times with hot hydrochloric acid concentration of 3 mol/DM, adding wash liquid to the main filtrate. Filter the precipitate discarded.

The filtrate is passed through ion exchange column with anion exchange resin, previously washed with 50 cmof hydrochloric acid concentration of 3 mol/DMat a speed of approximately 0.5 cm/min. After the entire test solution is transferred into a ion exchange column, skip is still 70−100 cm(in portions of 10−20 cm) of hydrochloric acid concentration of 3 mol/DMfor removal of accompanying elements: Nickel, chromium, cobalt, manganese, copper, iron. The eluate discarded. When the last portion of the acid will reach the top level of the anion exchanger, desorber bismuth 300 cmof nitric acid of concentration 1 mol/DM.

2.3.2. Spectrophotometric assay procedure

The test solution prepared according to claim 2.3.1.1 or 2.3.1.2, evaporated to wet salts, the salts are dissolved in 5 cmof nitric acid and evaporated to dryness.

Then salt is dissolved in 3 cm.of nitric acid of concentration 1 mol/DMwhen heated, the walls of the glass should be rinsed with 3−5 cmof water, the solution was stirred and cooled. Add 2cmof a solution of ascorbic acid, mix, after 5 minutes pour 1 cmof a solution of tartaric acid concentration of 100 g/DMand 1 cmkylinalove orange solution, stirring the solution after each addition of the reagent. The solution was transferred to a volumetric flask with a capacity of 25 cm, top up to the mark with water and mix.

After 10 minutes measure the optical density of colored solution with spectrophotometer at a wavelength of 540 nm in a cuvette with the thickness of the light absorbing layer 1 cm or photoelectrocolorimeter with a green optical filter in a cuvette with a thickness of the light absorbing layer 5, see Solution comparison is the solution of the reference experiment. The mass of bismuth in test solution found by the calibration schedule.

2.3.3. Construction of calibration curve

Five cups (or flasks) with a capacity of 250−300 cmis placed hitch carbonyl iron 0.5−1 g in accordance with the weight of the portion of the sample steel. Four cups (or flasks) poured successively 0,5; 1,0; 3,0; 5,0 cmstandard solution B. the Fifth Cup is for holding the control (blank) experience.

All glasses add 20 cmof hydrochloric acid and 5 cmof nitric acid. Then do as stated in claim 2.3.1 with the method of separation of bismuth from the basic components in section 2.3.2.

3. FLAMELESS ATOMIC ABSORPTION METHOD

3.1. The essence of the method

The method is based on measuring absorption of radiation by free atoms of bismuth at a wavelength of 223,1 or 306,8 nm, formed with the introduction of the analyzed solution into the graphite cuvette.

Bismuth is pre-separated from the main components of the steel by precipitation as a sulfide by thioacetamide in ammoniacal solution in the presence of the collector of sulphide of copper and tartaric acid as complexing agents or by the method of ion exchange chromatography.

3.2. Apparatus, reagents and solutions

Atomic absorption spectrophotometer with graphite cuvette.

Lamp for determination of bismuth.

Pipette with a capacity of 20 micysmf.

Argon of high purity according to GOST 10157 or a mixture of argon with 5% hydrogen.

A standard solution of bismuth: 10 cmof solution B prepared according to claim 2.2, is placed in a volumetric flask with a capacity of 100 cm, add 10 cmof nitric acid, made up to the mark with water and mix. The solution is prepared immediately before use.

1 cmstandard solution contains 0,000001 g of bismuth.

Other reagents, solutions and apparatus according to claim 2.2.

3.3. Analysis

3.3.1. Preparation of test solution

The weight and steel weight 0,1−1 g according to table.1 is placed in the beaker (or flask) with a capacity of 250−300 cm, pour 15−20 cmof hydrochloric acid and 5 cmof nitric acid, cover the beaker (or flask) watch glass and dissolve the sample when heated.

Table 1

Then do as stated in claim 2.3.1, separating bismuth from the main components in the form of sulphide or the thioacetamide by the method of ion exchange chromatography.

3.3.2. Spectrometric analysis procedure

The test solution prepared according to claim 2.3.1.1 or 2.3.1.2, evaporated to wet salts. Salt dissolved in 5 cmof nitric acid and again evaporated to moist salts. Then salt is dissolved by heating in 10 cmof nitric acid (1:1), covering the beaker watch glass, and cooled. The solution was transferred to volumetric flask (see table 1), made up to the mark with water and mix. Take a micropipette aliquot part of the solution, equal to 20 micysmf, is introduced into a graphite cuvette and record the amount of radiation absorption by free atoms of bismuth at a wavelength of 223,1 or 306,8 nm; for measurements taken at least three alikvotnih parts of the solution.

A lot of bismuth find the calibration schedule subject to amendments the reference experiment.

3.3.3. Preparation of the device for measuring

Activation of the device, setting the spectrophotometer at the resonant radiation, the adjustment of the control unit, block, atomization is carried out according to the instructions supplied with the device.

The conditions for the determination of bismuth:

The analytical line () — 223,1 or 306,8 nm.

The spectral slit width of 0.2 nm.

Drying time at 100 °C — 10 s.

The decomposition at 560 °C — 15 s

Time atomaticaly at 1930 °C — 10 s.

Mode inert gas «gas-stop».

3.3.4. Construction of calibration curve

Five cups (or flasks) with a capacity of 250−300 cmis placed sample of carbonyl iron in the amount corresponding to the weight of the steel (see table.1). Four cups (or flasks) poured consistently 1,0; 2,0; 4,0; 5,0 cmstandard solution Into the bismuth. The fifth glass (or flask) used for carrying out control of the experience.

In all the cups (or flasks) is added to 20 cmof hydrochloric acid and 5 cmof nitric acid.

Then do as stated in claim 2.3.1 with the method of separation of bismuth from the main components in PP.3.3.2, 3.3.3.

From the values of absorbance of analyzed solutions is subtracted the value of optical density in the reference experiment. The found values of optical density and corresponding mass of bismuth build the calibration graph.

4. INVERSION-VOLTAMMETRIC METHOD

4.1. The essence of the method

The method is based on the preconcetration of bismuth on a stationary mercury drop or a mercury-graphite electrode at a potential of -0.5 V In hydrochloric acid of concentration 1 mol/DMwith the subsequent registration of the current of anodic dissolution of bismuth in the minus potential of 0.15 V relative to silver chloride electrode.

Bismuth is separated from the main components of the steel by precipitation as a sulfide by thioacetamide in ammoniacal solution in the presence of the collector of sulphide of copper and tartaric acid as complexing agents or by the method of ion exchange chromatography.

4.2. Apparatus, reagents and solutions

Polarograph AC, oscilloscope or DC.

Cell with silver chloride reference electrode, a stationary mercury drop electrode of any design or hard disk electrode (4 mm) from graphitemoderated material of any method of manufacture that provides the required NTD reproducibility of the analytical signal.

Potentiostat any model operating in the mode specified capacity.

Mercury brands r0 according to GOST 4658 containing no moisture.

Nitrogen gas according to GOST 9293 or argon according to GOST 10157.

Background for polarographically containing 1 mol/DMof hydrochloric acid. If necessary, is subjected to further electrochemical purification scheme drawing from impurities of non-ferrous metals with a mercury cathode within 4−5 h at a potential of minus 1.2 V, which is kept constant by using a potentiostat.

Potassium chloride according to GOST 4234, saturated solution.

Mercury (II) nitrate oxide according to GOST 4520, solution concentration 0.001 g/cmin nitric acid (1:15).

Aljumokalievyh alum GOST 4329, solution concentration of 10 g/DM.

Ammonium nitrate according to GOST 22867.

Standard solutions of bismuth.

Solution B: 10 cmsolution A (p.2.2) is placed in a volumetric flask with a capacity of 100 cm, add 2 cmof hydrochloric acid, made up to the mark with water and mix.

1 cmstandard solution B has the 0.00001 g of bismuth.

Solution: 5 cmof solution B is placed in a volumetric flask with a capacity of 50 cm, add 2 cmof hydrochloric acid, made up to the mark with water and mix.

1 cmstandard solution contains 0,000001 g of bismuth.

Solution prepared immediately before use.

The other reagents and solutions according to claim 2.2.

4.3. Analysis

4.3.1. Preparation of test solution

A sample of steel weighing 0.5 g were placed in a glass (or flask) with a capacity of 250−300 cm, pour 15−20 cmof hydrochloric acid and 5 cmof nitric acid, cover the beaker (or flask) watch glass and dissolve the sample when heated.

Then do as stated in claim 2.3.1, separating bismuth from the basic components in the form of a sulfide by thioacetamide (p.2.3.1.1) or by ion-exchange chromatography (p.2.3.1.2).

The test solution obtained according to claim 2.3.1.1, evaporated to dryness, the salt dissolved in 3 cm.of nitric acid when heated and diluted with water to approximately 80 cm. To the obtained solution poured 10 cmof the solution aljumokalievyh alum, and 0.5 g nitrate ammonium and ammonia to a faint smell. The contents of the beaker (or flask) and heated for 1−2 min, the precipitate was filtered off on a medium density filter (white ribbon) and washed 3−4 times with hot dilute (1:200) with ammonia. The filtrate is discarded. The filter cake is dissolved in 10 cmof hot hydrochloric acid (1:1) and washed the filter 2−3 times with hot water collecting the filtrate and washings into the beaker (or flask) in which conducted the deposition.

1 — the working mercury electrode; 2 — platinum contact; 3 — stirrer; 4 — auxiliary electrode from the spectra of coal; 5 — silver chloride reference electrode; 6 — polyethylene vessel; 7 — cover; 8 — glass tube for supplying nitrogen; 9 — siphon for draining the electrolyte

4.3.2. Inversion-voltammetric analysis procedure

The test solution obtained according to claim 4.3.1 after separation of the bismuth from the basic components, was evaporated to dryness. Salt dissolved in 5 cmof hydrochloric acid and again evaporated to dryness. Then salt is dissolved by heating in 4 cmof hydrochloric acid, covering the beaker watch glass, and cooled. The solution is diluted with water and transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix.

When working with a stationary mercury drop electrode in the polarographic cell is filled 20−25 cmof the background electrolyte, through which previously within 5 min purged nitrogen or argon, are added in accordance with table.2 aliquot part of the test solutions, 0.01−0.02 g ascorbic acid and mix.

Table 2

Set on polarography potential minus 0.5 V and carried out the concentration of bismuth on the stationary mercury drop electrode in a continuously stirred solution over 2−3 min. At the end of the accumulation time stops stirring, and the solution settles down within 15−20 seconds, then removed the anodic polarization curve with linearly varying electrode potential from minus 0.5 to minus 0.05, registering a peak of bismuth at a potential of minus 0.15 V. For each measurement, get a new drop of mercury.

When working with solid electrodes in the mode of mercury-graphite in the polarographic cell is filled 20−25 cmof the background electrolyte, through which previously within 5 min purged nitrogen or argon, add 3−4 drops of solution of nitrate of mercury (II) (150−200 mg), is added in accordance with table.3 aliquot part of the test solutions, 0.01−0.02 g ascorbic acid and mix.

Table 3

Set on polarography potential minus 0.5 V and carried out the concentration of bismuth in mercury-graphite electrode in a continuously stirred solution over 1−2 min. At the end of the accumulation time stops stirring, the solution settles down within 15−20 seconds, then removed the anodic polarization curve with linearly varying electrode potential from -0.5 to + 0.2 V. At a fixed potential value of 0.2 V plus the electrode is electrochemically cleaned in a stirred solution for 30 s after each recording of the polarization curve. The registration of curves is carried out three times, including the first measurement in the calculations is not taken into account. The maximum ionization current of bismuth (bismuth peak) is recorded at a potential of minus 0.15 V.

The sensitivity of the device during the registration of the voltammograms in both cases are selected so that the height of the recorded peak was at least 10 mm.

4.3.3. When working with a stationary mercury drop electrode, the content of bismuth find the calibration schedule given in the reference experiment.

To construct the calibration curve five cups (or flasks) with a capacity of 250−300 cmis placed 0.5 g of carbonyl iron and poured 20 cmof hydrochloric acid and 5 cmof nitric acid. Four cups (or flasks) pour the standard solution of bismuth in increasing amounts so that the weight of bismuth in the test sample of steel was approximately in the middle of the chart (see table.3). The fifth glass (or flask) used for carrying out control of the experience.

Then do as indicated in the claims.2.3.1 and 4.3.1, based on the selected method of separation of bismuth from the main components and p. 4.3.2.

The values of peak height analyzed solutions subtract the value of the peak height reference experiment. The found values of height and corresponding masses of bismuth build the calibration graph.

When working with a mercury-graphite electrode, the content of bismuth find the method of standard additions.

Aliquot part of the standard solution of bismuth is added to the test solution in a polarographic cell, stirred, then conduct Stripping voltammetric measurements (according to claim 4.3.2) in the determination of bismuth test solution.

The value of the standard additives are selected so that the peak height of bismuth after the introduction of the additive increased 1.5−2 times.

5. POLAROGRAPHIC METHOD

5.1. The essence of the method

The method is based on the ability of bismuth to recover on dripping mercuric electrode in hydrochloric acid of concentration 1 mol/DMat a potential of minus 0.15 V relative to silver chloride electrode.

Bismuth is separated from the main components of the steel by precipitation as a sulfide by thioacetamide in ammoniacal solution in the presence of a sulfide of copper and tartaric acid as complexing agents or by the method of ion exchange chromatography.

5.2. Apparatus, reagents and solutions

Polarograph AC, oscilloscope or DC.

Cell with a mercury drop electrode.

Reagents and solutions according to claims.2.2 and 4.2.

5.3. Analysis

5.3.1. Preparation of test solution

Carried out as specified in clause 4.3.1.

5.3.2. Polarographic analysis procedure

The test solution obtained (section 4.3.1) after the separation of bismuth from the basic components, was evaporated to dryness. Salt dissolved in 5 cmof hydrochloric acid and again evaporated to dryness. Then salt is dissolved by heating in 4 cmof hydrochloric acid, covering the beaker watch glass, and cooled. The solution is diluted with water and transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix.

The solution after purging with inert gas filled in the cell and polarographic, registering the maximum current recovery of bismuth in the range of applied voltage from 0.05 to 0.3 V relative to silver chloride electrode or a mercury the bottom.

The sensitivity of the device during the registration of the voltammograms are selected so that the peak height was not less than 10 mm.

5.3.3. Construction of calibration curve

Five cups (or flasks) with a capacity of 250−300 cmis placed 0.5 g of carbonyl iron and poured 20 cmof hydrochloric acid and 5 cmof nitric acid. Four cups (or flasks) pour the standard solution B of bismuth in increasing amounts so that the weight of bismuth in the test sample of steel was approximately in the middle of the chart. The fifth glass (or flask) used for carrying out control of the experience.

Then do as indicated in the claims.2.3.1 and 4.3.1, based on the selected method of separation of bismuth from the basic components in section 5.3.2.

The values of peak height analyzed solutions subtract the value of the peak height reference experiment. The found values of height and corresponding masses of bismuth build the calibration graph.

6. PROCESSING OF THE RESULTS

6.1. Mass fraction of bismuth () in percent is calculated according to the formulas:

is calculated according to the calibration schedule

,

where  — weight of bismuth, was found in the calibration schedule g;

the weight of steel, g;

— when the method of additives

,

where is the peak height of bismuth on polarography of test solution, mm;

the peak height of bismuth on polarographically control experience, mm;

the peak height of bismuth after introduction into a cell of standard addition, mm;

 — the volume of standard addition, cm;

 — concentration of standard solution, g/cm;

the weight of steel, suitable aliquote part of the solution,

6.2. Norms of accuracy and norms control the accuracy of determining the mass fraction of bismuth is given in table.4.

Table 4