GOST 24018.3-80

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  ГОСТ 24018.3-80

GOST 24018.3−80 heat-resistant Alloys on a Nickel basis. Methods for determination of lead (with Amendments No. 1, 2)

GOST 24018.3−80

Group B39

INTERSTATE STANDARD

ALLOYS HIGH-TEMPERATURE NICKEL-BASED

Methods for determination of lead

Nickel-based fire-resistant alloys.
Methods for the determination of lead

ISS 77.120.40
AXTU 0809

Date of introduction 1981−07−01

INFORMATION DATA

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

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 28.02.80 N 958

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (ICS 11−95)

6. EDITION (August 2004) with Changes No. 1, 2 approved in December 1985, December 1990 (IUS 4−86, 3−91)


This standard sets the photometric method for the determination of lead (in mass fractions of from 0.0005% to 0,010%) and flameless atomic absorption method for the determination of lead (at a mass fraction of from 0.0002% to 0,010%).

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 24018.0.

2. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF LEAD

2.1. The essence of the method

The method is based on the formation in a slightly alkaline environment (pH of 11.5) in the presence of potassium cyanide chelation of lead with dithizone, painted in red color and extracted with chloroform. Maximum light absorption of the solution is observed at 520 nm.

Lead pre-separated from the deformity of the elements by precipitation as a sulfide by thioacetamide in ammoniacal solution (pH 7.5) in the presence of tartaric acid as complexing agents.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

a pH meter.

Thermometer.

Hydrochloric acid according to GOST 3118, GOST 14261 and diluted 1:1.

Nitric acid according to GOST 4461, GOST 11125 and diluted 1:1 and 1:100.

A mixture of hydrochloric and nitric acids: the 150 cmof hydrochloric acid pour 50 cmof nitric acid, stirred; and diluted 1:1, prepared immediately before use.

Tartaric acid according to GOST 5817, a solution with a mass concentration of 50 g/cm, (g/DM).

Ammonia water according to GOST 3760, GOST 24147 and diluted 1:1, 1:100, 1:200.

Buffer solution (pH 11,5):

to 10 cmof a solution of cyanide of potassium with a mass concentration of 10 g/cm, (g/DM), pour 5 cmof ammonia solution and add water to 100 cm.

The thioacetamide solution with a mass concentration of 2 g/cm(g/DM).

Ammonium neccersarily according to GOST 20478, a solution with a mass concentration of 25 g/cm, (g/DM).

Chloroform according to GOST 20015.

Ditson according to GOST 10165, solution with the mass concentration of 0.04 g/cm(g/DM) in chloroform:

0.04 g of dithizone placed in a beaker with a capacity of 100 cmand dissolved in 50 cmof chloroform. Solution dithizone in chloroform is transferred to a separatory funnel with a capacity of 200 cmand stirred with 200 cm(in series portions 50 cm) ammonia solution (1:100). Ditson passes into the aqueous ammonia layer and the oxidation products remain in the chloroform layer discarded. The solutions are combined and placed in a separating funnel with a capacity of 500 cm, is poured dropwise with hydrochloric acid (1:1) to pH 4.5 by universal indicator, add 100 cmof chloroform. The solution in the separating funnel shaken for 1 min.

The chloroform layer is drained into another separatory funnel with a capacity of 500 cmand washed 3 times with water. The resulting solution of dithizone in chloroform was filtered through dry cotton wool and stored in a flask made of dark glass in a cool place.

Dition, a solution with a mass concentration of 0.01 g/cm(g/DM) in chloroform (dishwashing and cleaning reagents): 25 cmdithizone solution with the mass concentration of 0.04 g/cm(g/DM) is transferred into a measuring flask with a capacity of 100 cm, made up to the mark with chloroform and mix.

Dition, a solution with a mass concentration of 0.002 g/cm(g/DM) in chloroform:

5 cmdithizone solution with the mass concentration of 0.04 g/cm(g/DM) is transferred into a measuring flask with a capacity of 100 cm, made up to the mark with chloroform and mix.

Hydroxylamine hydrochloride according to GOST 5456, solution with a mass concentration of 1 g/cm(g/DM), purified dithizone:

300 cmof a solution of hydrochloric acid hydroxylamine was placed in a separating funnel with a capacity of 500 cm, add drop by drop ammonia solution to pH 6−7 by universal indicator and shake successively with several portions of 10 cmsolution of dithizone with the mass concentration of 0.01 g/cm(g/DM) in chloroform until then, until the last portion of the chloroform becomes colorless.

Potassium cyanide, solution with a mass concentration of 10 g/cm, (g/DM).

Sodium citrate, a solution with a mass concentration of 10 g/cm, (g/DM), purified dithizone:

300 cmof a solution of sodium citrate is placed in a separating funnel with a capacity of 500 cmand shaken successively with several portions of 10 cmsolution of dithizone with the mass concentration of 0.01 g/cm(g/DM) in chloroform until then, until the last portion of dithizone will have a dark green color. Excess dithizone extracted with chloroform until, until the last portion of the chloroform becomes colorless.

Thymol blue, solution with the mass concentration of 0.04 g/cm(g/DM).

Nickel brand H0 according to GOST 849.

The Nickel powder.

Universal indicator paper pH 1−10.

Iron (III) nitrate 9-water in the NTD, a solution with a mass concentration of 1 g/cm(g/DM):

1 g of iron nitrate were placed in a glass with a capacity of 100 cm, is dissolved in 50 cmof water, pour 5 cmof nitric acid, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Copper grade М00бк according to the GOST 859.

The copper nitrate solution with a mass concentration of 1 g/cm(g/DM):

1 g of copper is dissolved by heating in 15−20 cmof nitric acid (1:1). The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Lead of stamps C0; C00; C000; S0000 according to GOST 3778.

Standard solutions of lead.

Solution a: 0.1 g of lead dissolved in 30 cmof nitric acid when heated. The solution was 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 lead.

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

1 cmstandard solution B has the 0.00001 g of lead.

Solution: 10 cmof solution B is placed in a volumetric flask with a capacity of 100 cm, flow 10 cmof nitric acid, made up to the mark with water and mix is prepared immediately before use.

1 cmstandard solution At the cedar

tains 0,000001 g of lead.

(Changed edition, Rev. N 1, 2).

2.3. Analysis

2.3.1. The weight of the alloy (tab.1) were placed in a glass (or flask) with a capacity of 250−300 cm, 30 cm, pour themixture of hydrochloric and nitric acid, cover with watch glass and dissolved under heating. The solution was evaporated to a volume of approximately 10 cm. Add 30 cmof water, 20 cmof a solution of tartaric acid and heated for 10 min. To the solution was added 1 cmof solution of nitrate of copper, pour 20−30 cmof ammonia solution and again heat for 5−8 min, Set pH 7.5 with hydrochloric acid (1:1) using pH meter. Dilute the solution with water to approximately 150 cm, heated to 85 °C — 90 °C, pour 10 cmof a solution of thioacetamide and incubated for 10 min at the same temperature. Newly poured 10 cmof a solution of thioacetamide, and leave the solution to precipitate for 2 h at 40 °C — 50 °C and cooled. The precipitate is filtered off sulphides in two medium density filter (white ribbon), washed 7−8 times with cold water. The filtrate is discarded. The filter cake was dissolved in 40−50 cm(chunks 10 cm) of a hot mixture of hydrochloric and nitric acids (1:1) and the filter was washed 2−3 times with hot water collecting the filtrate and washings in a beaker, which carried out the deposition. The solution was evaporated to dryness, poured 3−5 cmof nitric acid and heat the contents of the beaker to dissolve the salts. The solution is poured 70−100 cmof water, 20 cmof naternicola solution of ammonia and boiled for 10−15 min. Then pour 1 cmof solution of nitrate of iron, solution of ammonia until the appearance of stable precipitate hydroxides of metals and ammonia abundance of 0.5−1 cm. The precipitate was filtered off on a medium density filter (white ribbon) and washed 8−10 times with hot ammonia solution (1:200). The filter cake is dissolved in 5 cmof hot nitric acid (1:1), the filter was washed 7−8 times with hot water collecting the filtrate and washings into the beaker (or flask) in which conducted the deposition.

Table 1

For the mass concentration of lead in the alloy is from 0.0005% to 0.001%, the solution was evaporated to dryness, the salt dissolved in 1 cmof nitric acid (1:1) under heating. The solution was cooled, transferred to 10 cmof water in a separating funnel with a capacity of 100 cm.

For the mass concentration of lead in the alloy in excess of 0.001% to 0.01% solution transferred to a volumetric flask with a capacity of 50 cm, cooled, made up to the mark with water and mix. Aliquot part of the solution (see table.1) is placed in a separating funnel with a capacity of 100 cmand pour 5 cmof nitric acid (1:100).

To the contents of the separating funnel pour 2 cmof a solution of sodium citrate, 1 cmof a solution of hydrochloric acid hydroxylamine and three drops of thymol blue solution.

Neutralized with ammonia solution until the color of the indicator from pink to blue (pH of 9.5). Then pour the 2 cmbuffer solution (pH 11,5), mix, add 10 cmof a solution of dithizone with the mass concentration of 0.002 g/cm(g/DM), (from burette) and shaken for 1 min. Aqueous and chloroform layers allowed to settle and decanted chloroform layer in a dry cuvette with a layer thickness of 10 mm. after 10 min the optical density of the solution measured by the spectrophotometer at 520 nm or photoelectrocolorimeter with a filter having a region of transmittance in the wavelength interval from 480 to 540 nm. As a comparison, using a solution of chloroform.

The weight of lead found by the calibration schedule subject to amendments the reference experiment.

2.3.2. Construction of calibration curve

Six glasses or flasks with a capacity of 250−300 cmis placed 0.5 g of metallic Nickel or Nickel powder.

Five beakers or flasks poured successively 4, 6, 8, 10, 12 cmstandard solution Into the lead. The sixth glass is used for the reference experiment. All glasses add 30 cmof a mixture of hydrochloric and nitric acids. Glasses cover watch glass and heated until complete dissolution of batches.

Then do as mentioned in paragraph 2.3.1, 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 of solutions and their corresponding masses lead to build a calibration curve.

2.3.1, 2.3.2. (Changed edition, Rev. N 1, 2).

2.4. Processing of the results

2.4.1. Mass fraction of lead (a) percentage calculated by the formula

,

where is the mass of lead was found in the calibration schedule g;

 — the weight of the portion of alloy, suitable aliquote part of the solution,

2.4.2. The absolute differences of the results of the parallel definitions should not exceed (at p = 0.95) of permissible values, specified in table.4.

(Changed edition, Rev. N 2).

3. FLAMELESS ATOMIC ABSORPTION METHOD FOR DETERMINATION OF LEAD

3.1. The essence of the method

The method is based on measuring absorption of radiation by free atoms in of lead is 283.3 nm, formed with the introduction of the analyzed solution into the graphite cuvette. Lead pre-separated from the deformity of the elements by precipitation as a sulfide by thioacetamide in ammoniacal solution (pH 7.5) in the presence of tartaric acid as a complexing agent and copper sulfide as a collector.

(Changed edition, Rev. N 1).

3.2. Apparatus, reagents and solutions

Atomic absorption spectrophotometer with electrothermal atomizer.

Lamp for determination of lead.

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

a pH meter.

Thermometer.

Hydrochloric acid according to GOST 3118, GOST 14261.

Nitric acid according to GOST 4461, GOST 11125 and diluted 1:1.

A mixture of hydrochloric and nitric acids: the 150 cmof hydrochloric acid add 50 cmof nitric acid, and mix; dilute 1:1.

The mixture of acids prepared immediately before use.

Tartaric acid according to GOST 5817, a solution with a mass concentration of 50 g/cm, (g/DM).

Ammonia water according to GOST 3760.

The thioacetamide aqueous solution with a mass concentration of 2 g/cm(g/DM), according to GOST 24147.

Copper grade М00бк according to the GOST 859.

The copper nitrate solution with a mass concentration of 1 g/cm(g/DM);

1 g of copper metal is dissolved by heating in 15−20 cmof nitric acid (1:1).

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

Nickel brand H0 according to GOST 849.

Lead of stamps C0, C00, C000, S0000 according to GOST 3778.

Standard solutions of lead.

Solution a: 0.1 g of lead dissolved in 30 cmof nitric acid, 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 lead.

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 lead.

Solution: 10 cmof solution B 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 is prepared immediately before use.

1 cmstandard solution contains 0,000001 g of lead.

Universal indicator paper pH 1−10.

(Modified, edited by

I, ISM. N 1, 2).

3.3. Analysis

3.3.1. The weight of the alloy (tab.3) is placed in a beaker or flask with a capacity of 250−300 cm, 30 cm, pour themixture of hydrochloric and 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 cmof a solution of tartaric acid and heated for 10 min. the Solution was cooled, add 20−25 cmof ammonia solution to pH 8−10 by universal indicator, and again heated for 10 min to dissolve the precipitated tungsten and niobium acids.

Table 3*
___________________________
* Table.2. (Deleted, Rev. N 2).

To the solution was added 1 cmof solution of nitrate of copper, set pH 7.5 by adding hydrochloric acid (1:1) using pH meter. The solution is diluted with water to about 150 cm, heated to 85 °C — 90 °C, pour 10 cmof a solution of thioacetamide, incubated 10 min at the same temperature. Newly poured 10 cmof a solution of thioacetamide solution and leave to precipitate for 2 h at 40 °C — 50 °C. Then the solution was cooled. The precipitate is filtered off sulphides in two medium density filter (white ribbon), washed 7−8 times with cold water, the filtrate discarded. The filter cake was dissolved in 40−50 cm(chunks 10 cm) of a hot mixture of hydrochloric and nitric acids (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. The filter is discarded, the solution was evaporated to dryness, add 3 cmof nitric acid and again evaporated to dryness. Salt dissolved in 5 cmof nitric acid (1:1) when heated, covering the glass or flask glass, cool. The solution was transferred to volumetric flask (see table 3), mixed together, were taken by micropipette aliquot part of the solution (see table.3), enter it in the electrothermal atomizer and record the amount of radiation absorption by using a registered device. For measurements taken at least three alikvotnih parts of the solution. The weight of lead found by the calibration schedule with the adjusted control experience

.

3.3.2. 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.

Conditions for determination of lead:

The analytical line () — is 283.3 nm.

Operating current of the lamp is 25 mA.

Drying time at 100 °C — 10 s.

The decomposition at 800 °C — 10 s.

Time atomization at 2100 °C — 10 s.

The determination is carried out in a minimal flow of gas at the atomization stage.

3.3.3. Construction of calibration curve

Six of cups (or flasks) with a capacity of 250−300 cmis placed 0.5 g of metallic Nickel or Nickel powder. In five glasses poured sequentially 1, 2, 4, 6, 8 cmstandard solution Into the lead. The sixth glass is used for the reference experiment.

In all the cups (or flasks) poured in 30 cmof a mixture of hydrochloric and nitric acid, cover with watch glass and dissolve the sample when heated. The solutions were evaporated to a volume of approximately 10 cm, add 30 cmof water, 20 cmof a solution of tartaric acid and heated for 10 min. Then do as stated in claim 3.3.1.

After dissolving the salts in 5 cmof nitric acid (1:1) the resulting solutions are transferred to volumetric flasks with a capacity of 25 cm, made up to the marks with water, mix. Take a micropipette aliquot part of the solution 20 micysmf, injected into the electrothermal atomizer and record the amount of radiation absorption by using a registered device. For measurements taken at least three alikvotnih parts of the solution. 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 lead build the calibration graph

IR.

3.3.1−3.3.3. (Changed edition, Rev. N 2).

3.4. Processing of the results

3.4.1. Mass fraction of lead (a) percentage calculated by the formula

,

where is the mass of lead was found in the calibration schedule g;

 — weight alloy, g;

 — the volume of a standard solution of lead used to build the calibration curve, cm;

 — the volume of the analyzed solution alloy, cm;

 — aliquota part of the standard solution used to build the calibration curve, micysmf;

 — aliquota part of the analyzed solution alloy, MK

DM.

3.4.2. The absolute discrepancies in the results of parallel measurements (at p = 0.95) must not exceed the permissible values given in table.4.

Table 4

(Changed edition, Rev. N 2).