GOST 16274.8-77

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  ГОСТ 16274.8-77

GOST 16274.8−77 Bismuth. Spectral methods of analysis (with Amendments No. 1, 2, 3)

GOST 16274.8−77

Group B59

STATE STANDARD OF THE USSR

BISMUTH

Spectral methods of analysis

Bismuth. Spectral methods of analysis

AXTU 1709

Date of introduction 1978−01−01

INFORMATION DATA

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

DEVELOPERS

PS Poklonsky, F. M. Manji, G. V. Khabarova

2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 25.01.77 N 172

3. The frequency of inspection 5 years

4. REPLACE GOST 16274.8−70

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. Resolution of the state standard from 30.07.92 N 836 removed the limitation of the validity period

7. REPRINT (July 1997) with Amendments No. 1, 2, 3, approved in January 1983, June 1987, July 1992 (IUS 5−83, 11−87, 10−92)


This standard applies to the grades Vi00 bismuth, Vi1, Vi2 and sets the spectral methods of determination of silver, copper, cadmium, lead, tellurium, zinc, antimony, iron, cobalt, manganese, and chemical-spectral method for the determination of arsenic and tellurium.

(Changed edition, Rev. N 2, 3).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 16274.0.

2. SPECTRAL METHOD of the ANALYSIS of BISMUTH BRANDS Vi1 and Vi2

2.1. The essence of the method

The method is based on excitation and registration of the emission spectrum of the sample.

Estimation of concentration of elements produced by comparing pucherani and intensities of spectral lines in the samples and the calibration samples.

It provides for the determination of impurities in percent concentrations:

2.2. Apparatus, reagents and solutions

The quartz type spectrograph ISP-28 with a three-lens Achromat lighting system (you can use a quartz spectrograph medium dispersion of any other type).

The damping of the three — and nine -.

The spark generator of the type IG-2 or IG-3.

Arc generator type DG-2.

Microphotometer designed to measure pucherani spectral lines.

Porcelain crucibles No. 5 and 6.

Cup porcelain No. 2.

The iron crucibles with a capacity of 150−200 cm.

A muffle or crucible furnace with temperature control up to 600 °C.

Mold for casting electrodes of cylindrical shape with a diameter of 8 mm, a length of 50−100 mm.

Analytical scale.

Files for sharpening electrodes.

The machine tool for sharpening of electrodes.

Photographic plates spectrographic type II slide.

Carbon electrodes, carbon from spectral coals brand-2; the bottom crater with a depth of 3 mm, diameter 4 mm and wall thickness 0.5−0.7 mm, the upper is sharpened to a truncated cone with ground diameter of 1.5−2.0 mm.

The quartz device for the distillation of water and acids with quartz refrigerator and sink.

Nitric acid is the OS.H.21−4 or OS.H.21−5 GOST 11125 and diluted 1:1, 1:2.

Salt is the disodium Ethylenediamine tetraoxane acid (Trilon B) according to GOST 10652, 10% solution.

Calcium chloride, on the other 6−09−4711, solution 0,05 mol/DM.

Ammonium nitrate according to GOST 22867, 5% solution.

The aqueous ammonia of high purity according to GOST 24147 and a solution of 1:1.

Selenology orange, 0,5% aqueous solution.

Bismuth nitrate according to GOST 4110.

The brand Vi00 bismuth GOST 10928.

Spectral-pure oxide of bismuth; prepared as follows: 300−400 g of bismuth brand Vi00 dissolved in 1000−1500 cmof nitric acid, diluted 1:1. Dissolution carry out individual portions at 40−50 g of metal. The resulting solution of nitrate of bismuth is evaporated to a syrupy state in a water bath.

Spectral-pure oxide of bismuth can be prepared from the nitrate of bismuth. In this case, 300−400 g of bismuth nitrate is dissolved in small quantity of distilled water, acidified with nitric acid, and evaporate the solution to syrupy state. The obtained thick solution is poured in small portions (5−10 cm) with careful stirring in a conical flask containing 2000 cmof boiling water.

Thus fall crystalline precipitate of the basic nitrate of bismuth. For better crystallization of the contents of the flask again, bring to the boil and leave for 2−3 h. then poured the solution leaving a residue of basic nitrate of bismuth. The precipitate is filtered through a dense filter, and washed three times with water, acidified with nitric acid, after which the precipitate was transferred to a quartz beaker, dissolve by the addition of hot concentrated nitric acid, again evaporated to a syrupy condition, and then dried, calcined at 500 °C and spectral-pure bismuth oxide and store it in a closed jar.

Libra torsione type W, the weighing limit up to 1000 mg.

Note. Allowed the use of devices with photovoltaic spectra and other spectral instruments, other reagents, materials and photographic plates, generating accuracy metrics defined in this standard.


(Changed edition, Rev. N 1, 2, 3).

2.3. Determination of silver, lead and copper

2.3.1. Sample preparation

Spectral analysis is subjected to the sample in the form of rods with diameter of 8 mm and a length of 50−100 mm.

A sample is taken with a spoon from the pot during casting of the metal or melt the metal powder of bismuth under a layer of carbon powder in an iron crucible. Molten bismuth poured into the mold. Samples comparison sharpen on a plane with a file.

(Changed edition, Rev. N 1, 2, 3).

2.3.2. Sample preparation comparison.

Prepare the alloys of lead and bismuth, silver and bismuth, copper and bismuth. The obtained alloys analyzed by chemical methods and fused in the correct proportions. Then the ligature is diluted with Vi00 bismuth stamps and receive samples of comparison, which contains a number of impurities (tab.1). The concentration of impurities in the samples comparison set chemical methods given in this standard.

Table 1

Note. Mass fraction of impurities in the samples may differ from those in the table by ±30 Rel. %.


(Changed edition, Rev. N 2, 3).

2.3.3. Analysis

As excitation source using a spark generator of the type IG-3 and IG-2, enabled by a complex scheme. The mode of operation of the generator:

the current in the primary circuit of the transformer, 1.2 A;

the auxiliary spark gap — 3 mm;

analytical gap — 4.5 mm;

the inductance — 0,15 mg;

the capacitance is 0.005 UF.

The spectra are photographed on the type of spectrograph ISP-28 with a three-lens Achromat lighting system. The width of the slit of a spectrograph 0,02 mm. Exposure — 45 C.

Manifestation and fixation of the plates are as specified in GOST 16274.0.

2.3.4. Processing of the results

The applied analytical lines and lines of comparison are given in table.2.

Table 2

The concentration of impurities is determined using the three comparison samples. Three range of samples comparisons and six spectra of the samples are photographed on a single photographic plate.

Measure the blackening of the lines of each impurity by using microphotometry and comparison lines . Find the difference between pochernenija lines define the impurities and lines of bismuth selected as comparison lines:

.

Three parallel spectrograms determine the arithmetic mean of the difference of pochernenija .

The results of electrophoretic comparisons of samples to build calibration graphs for the determination of impurities.

The axis of ordinate delay difference pucherani impurities and the main substances, and x — axis is the logarithms of the concentrations of impurities in the reference sample.

The impurity content in the metal bismuth find known values for the respective calibration graphs.

The convergence of the method is characterized by the relative standard deviation of not more than 0.03 in the determination of lead, silver and not more than 0.1 in the determination of copper.

The discrepancy between the results of two parallel measurements () and the results of two tests () at a confidence probability of 0.95 should not exceed the permissible differences given in table 2A.

Table 2A

Permitted discrepancies for the intermediate mass fraction calculated using linear interpolation or according to the formulas:

; in the determination of lead and silver;

; in the determination of copper,

where is the arithmetic mean of the results of two parallel determinations;

 — the arithmetic mean of the results of the two tests.

The analysis result should be the arithmetic mean of two parallel definitions for the three spectrograms, each received on the same photographic plate.

(Changed edition, Rev. N 3).

2.4. Determination of antimony, iron, zinc, arsenic and tellurium.

2.4.1. Preparation of samples for the determination of antimony, iron, zinc

1 g of bismuth placed in a porcelain crucible, pour 5−10 cmof nitric acid, diluted 1:1, and dissolved under moderate heating. The solution was evaporated to dryness, the residue calcined for 30 min in a muffle at 500 °C to obtain bismuth oxide. The prepared sample is ground in an agate mortar to a particle size of minus 0,074 mm and transferred to a spectral analysis. Definition of lead from the two parallel batches.

(Changed edition, Rev. N 1, 3).

2.4.2. Preparation of concentrate of arsenic and tellurium

Concentrate arsenic and tellurium get trigonometricheskimi method, based on the property of complexonate of bismuth in the environment ammonia (at pH 8) by the addition of calcium salts to enter complexonate of calcium. Extruded bismuth precipitates as hydroxide, carrying with him the arsenic, tellurium and other trivalent metals.

Six batches of bismuth at 3 g was placed in a conical flask heat resistant glass with a capacity of 250 cm, flow 15 cmof nitric acid, diluted 1:1, cover the watch glass and with moderate heating is dissolved. After dissolution of the sample watch glass is removed and the solution was heated to remove vapors of nitrogen oxides. Then pour the 45 cmof hot 10% strength solution of Trilon B and hot water to bring the solution volume to 100 cm. Then add the indicator kylinalove orange (2−3 drops) and titrate a solution of 10% hot solution of Trilon B to switch crimson colouring in yellow.

The solution is neutralized with ammonia to a pH of 5 on the indicator paper, titrate hot solution of Trilon B till the appearance of yellow staining, add 5 cmof ammonia solution diluted 1:1, 4−5 cmcalcium chloride solution 0.05 mol/DMand boil for 2 min to sediment. An excess of calcium chloride leads to an increase in weight of the concentrate, i.e. the decrease of the coefficient of enrichment.

The precipitate stand at a low heat for 15 min, filtered through a dense filter and washed with hot 5% ammonium nitrate solution. Then the filter cake is dissolved in small quantity of hot nitric acid diluted 1:2, collecting the solution in a weighted porcelain Cup for evaporation. This same Cup to collect the solution from two parallel test portions of bismuth. The solution was evaporated at low heat, then on a hot stove. The edges of the cooled cups washed 2−3 cmof nitric acid and again evaporated at low heat. The precipitate is calcined in the muffle for 30 min at 500 °C until spectral-pure bismuth oxide. Cups with oxide of bismuth is weighed, determine the mass of the precipitate and set the enrichment coefficient by dividing the original sample of 9 g (3 sample 3 d) to ground the resulting precipitate. The concentrate is passed for spectral analysis. At the same time through the whole course of analysis with a number of reagents spent on three parallel hinges, conduct control experience for an amendment in the result analysis

.

2.4.3. Sample preparation comparison

10 g of the spectral-pure bismuth oxide dissolved in nitric acid, add 10 cmsolutions containing 1 mg/cmiron, antimony, zinc and arsenic.

The solution was evaporated to dryness, the residue was calcined at 500 °C. the Residue is moistened with water (2−3 cm) and add 10 cmto the standard solution of tellurium (concentration 1 mg/cm). The residue is dried under low heat. Preparation of standard solutions — application to GOST 16274.1.

Get the basic sample containing 0.1% of iron, antimony, zinc, arsenic and tellurium. Samples of comparison with the content of impurities 0,03; 0,01; 0,003; 0,001% prepared by successive dilution of the main sample comparison of spectral-pure oxide of bismuth.

2.4.2, 2.4.3. (Changed edition, Rev. N 1, 2, 3).

2.4.4. Analysis

Sample 30 mg of the prepared samples and comparison samples are placed in the craters of carbon electrodes. From each sample, and comparison sample are prepared according to two electrodes.

The spectra are photographed on the type of spectrograph ISP-28 with a three-lens Achromat lighting system. The slit width is 0.025 mm, the strength of the arc current to 15 And the generator type DG-2. Exposure — 40 C. In the cassette placed two photographic plates: in the visible region of the spectrum, spectrographic type II, in the long-wave — slide.

For plotting the characteristic curve on the same plate photographed range of the iron through a nine-reliever. Manifestation and fixation of the plates are as specified in GOST 16274.0.

2.4.5. Processing of the results

The resulting spectrograms to measure the blackening () the lines of the following wavelengths (table.3) and a minimum darkening of the background to the right and to the left of them.

Table 3

The average of the two background pucherani accept as true darkening of the background. Measure the degree of intensity to build the characteristic curve.

In the characteristic curve of photographic plates to find the appropriate measured pochernenija the values of the logarithms of the intensity , .

Calculate the value of a , find the arithmetic mean of the results obtained on the three spectrograms of each calibration sample and build the calibration graphs in the coordinate , where the impurity content in the samples of the comparison in percent. All calculations are made using the design tool.

According to the obtained calibration chart find the content of impurities, the respective calculated sample values

.

Discrepancies in the results of two parallel measurements () and the results of two tests () at a confidence probability of 0.95, should not exceed the permissible differences given in table 3A.

Table 3A

Permitted discrepancies for the intermediate mass fraction calculated using linear interpolation or according to the formulas:

; in the determination of iron, antimony and zinc;

; in the determination of arsenic and tellurium,

where is the arithmetic mean of the results of the two analyses.

 — the arithmetic mean of the results of parallel measurements.

For the results analysis be the arithmetic mean of results of two parallel measurements obtained on the same photographic plate (in the determination of arsenic and tellurium is prepared by two of the concentrate, each of which is obtained by combining solutions from the three batches of bismuth).

2.4.4, 2.4.5. (Changed edition, Rev. N 2, 3).

3. SPECTRAL METHOD of the ANALYSIS of BISMUTH BRAND Vi00

3.1. The essence of the method

The method is based on excitation and registration of the spectrum of core elements and impurities in the arc DC. A quantitative assessment of the content of impurities is carried out by comparison of the intensities of the spectra of samples and sample comparison.

Direct spectral method provides for the determination of metal impurities in the bismuth percentage in the following concentrations:

(Changed edition, Rev. N 2, 3).

3.2. Apparatus, reagents and solutions

The quartz type spectrograph ISP-28 with a three-lens Achromat lighting system (you can use a quartz spectrograph medium dispersion of any other type).

The damping of the three — and nine -.

Arc generator type DG-2.

A constant current source, providing a voltage less than 200 V and are designed for a load not less than 30 A.

Microphotometer designed to measure pucherani spectral lines.

Analytical scale.

Carbon electrodes, carbon from spectral coals brand-2 lower with a crater depth of 6 mm and 4.5 mm in diameter.

Pestles and mortars, steel and agate.

Photographic plates spectrographic types II and UFS.

Grinding machine carbon electrodes.

Boxes, cuvettes, glass caps for storage electrodes.

Formalin according to GOST 1625.

Rectified ethyl alcohol according to GOST 18300.

Phenol on the other 6−09−5303 or medical glue BF-6, diluted with ethanol 1:5.

Bakelite adhesive; prepared as follows: 25 g of phenol and 25 g of formalin was placed in a weighted porcelain Cup and heated in a water bath, then add 5−7 cmof ammonia and put in boiling water bath (ammonia is prepared by saturation of redistillate of water). Glue cook 5−6 hours, stirring with a stick until, until it becomes yellow-amber, transparent. Elongated quartz wand thread glue must be thin and brittle, the glue should not smell. When the glue is ready, it is weighed and immediately added alcohol to obtain a 5% solution.

Bakelite adhesive store in a glass jar with a glass stopper.

Libra torsione type W, the weighing limit up to 1000 mg.

References prepared according to the application.

(Changed edition, Rev. N 1, 2, 3).

3.3. Sample preparation

5−10 g of the metal bismuth is crushed to a powder, ground in an agate mortar. The metal powder mixed in a quartz crucible with graphite powder in the ratio of 30:1. To the mixture add 5% alcoholic solution of bakelite glue or an alcohol solution of glue BF-6 at the rate of 2 cm25 g powder. The mixture was thoroughly stirred, dried at 100 °C and triturated.

(Changed edition, Rev. N 1, 2).

3.4. (Deleted, Rev. N 2).

3.5. Analysis

Carbon electrodes are pre-fired in an arc, the DC power of 12 And for 15 S.

After firing into the crater of a carbon electrode loaded with 30 mg of powder samples and sample comparison. For each sample, comparisons take three samples, six batches.

For registration of spectra using spectrograph of ISP-28 with a three-lens Achromat lighting system. The slot width is 0.01 mm. in Front of the slit of the spectrograph set the two-stage attenuator with steps of transmittance 10% and 100%. Samples comparison burn in the arc of a DC power of 12 A. Exposure — 2 min. Spectra of the samples and comparison samples are photographed three times at two parallel plates. Characteristic curve of photographic plates to build brands intensity (GOST 24977.1, Annex 2).

Manifestation and fixation of the plates are as specified in GOST 16274.0.

3.6. Processing of the results

Calculation of results of analysis carried out as specified in clause 2.4.5.

The applied analytical lines given in table.5.

Table 5

The convergence of the method is characterized by the relative standard deviation of not more than 0.2 in the determination of silver, copper, lead, cobalt, manganese, antimony, iron, and not more than 0.3 in the determination of cadmium, tellurium, zinc.

Discrepancies in the results of two parallel measurements () and the results of two tests () at a confidence probability of 0.95 should not exceed the values given in table.5A.

Table 5A

Permitted discrepancies for the intermediate mass fraction calculated using linear interpolation or according to the formulas:

; in the determination of silver, copper, lead, cobalt, manganese, antimony, and iron;

; in the determination of cadmium, tellurium and zinc

where is the arithmetic mean of the results of the two analyses.

 — the arithmetic mean of the results of parallel measurements.

The analysis result should be the arithmetic mean of two parallel definitions for the three spectrograms, each received on the same photographic plate.

3.5, 3.6. (Changed edition, Rev. N 1, 2, 3).

APP (mandatory). PREPARATION OF STANDARD SOLUTIONS AND SAMPLES TO BUILD A CALIBRATION CHART

APP
Mandatory

The basis for the preparation of samples of comparison is bismuth brands Ви0000 or Ви000. Impurities impose standard solutions on graphite powder, which is mixed in the ratio 1:30 with bismuth.

Standard solutions were prepared according to the Annex to GOST 16274.1 with the Supplement.

A standard solution of copper and cadmium: in a volumetric flask with a capacity of 100 cmshift 10 cmstandard solutions containing 5 mg/cmcopper, and cadmium. Bring to mark with water, mix.

1 cmof solution contains 0.5 mg of copper and cadmium.

Standard solution D of manganese and silver: in a volumetric flask with a capacity of 100 cmshift 10 cmstandard solutions B containing 1 mg/cmof manganese and silver. Bring to mark with water, mix.

1 cmof solution e contains 0.1 mg of manganese and silver.

Sample comparison N 1: in either quartz or Teflon Cup was placed 2 g of graphite powder and a calculated amount of standard solutions specified in the table.

The solution was evaporated to dryness under an infrared lamp at a temperature of (100±10) °C.

Method serial dilutions of the sample N 1 and each newly prepared sample graphite powder 2−3 times to get a series of working samples comparison.

1 g each of the prepared samples was placed in a mortar, add 30 g of finely powdered bismuth brands Ви0000 or Ви000, carefully grind. Then two steps of 2 cmis added an alcoholic solution of bakelite glue or glue BF-6, each time drying the adhesive solution at a temperature of (100±10) °C, and mixed again.

The samples of the comparison is stored in buksh or jars with lids.

(Changed edition, Rev. N 2, 3).