GOST 18385.2-79

• gost-183852-79.pdf (602.25 KiB)
  ГОСТ 18385.2-79

GOST 18385.2−79 Niobium. Spectral method for determination of silicon, titanium, and iron (with Amendments No. 1, 2)

GOST 18385.2−79

Group B59

STATE STANDARD OF THE USSR

NIOBIUM

Spectral method for determination of silicon, titanium, and iron

Niobium. Spectral method for the determination of silicon, titanium and iron

AXTU 1709*
______________
* Introduced advanced Edit. N 1.

Valid from 01.07.1980
before 01.07.1985*
_________________________________
* Expiration removed
Protocol 5−94 N Interstate Council
for standardization, Metrology and certification
(IUS N 11/12, 1994). — Note the manufacturer’s database.

DEVELOPED by the Ministry of nonferrous metallurgy of the USSR

PERFORMERS

A. V. Elyutin, Yu. A. Karpov, A. G. Valkanov, L. N. Filimonov, V. V. Korolev, V. V. Nedler, V. G., Miscreants, T. M. Malyutina, V. M. Mikhailov, E. G. Nembrini

INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

Member Of The Board Of A. P. Snurnikov

APPROVED AND promulgated by the Decree of the State Committee USSR on standards on may 30, 1979 N 1968

INSTEAD 18385.3 GOST-73

MADE: the Change in N 1, approved and put into effect by the Decree of the USSR State Committee for standards from 11.10.84 N 3561 with 01.03.85, Change No. 2, approved and put into effect by the Decree of the USSR State Committee on management of quality and standards from 08.12.89 N 3616 with 01.07.90

Change N 1, 2 made by the manufacturer of the database in the text IUS N 1, 1985, IUS N 3, 1990


This standard specifies the spectral method for determination of silicon (from 0.003 to 0.03%), titanium (from 0.003 to 0.1%) and iron (from 0.003 to 0.08%).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 18385.0−79*.
_______________
* On the territory of the Russian Federation GOST 18385.0−89. — Note the manufacturer’s database.

2. DETERMINATION of SILICON, TITANIUM, AND IRON (when the mass fraction of silicon of from 0.003 to 0.02%, titanium 0.001 to 0.01% iron 0.001 to 0,030%)

______________
* The name of the section. Changed the wording, Rev. N 1.

Method is based on the intensity of spectral lines of silicon, titanium and iron from their mass fraction in the sample with the excitation spectrum of the arc AC.

2.1. Apparatus, materials and reagents

The diffraction spectrograph DFS-8 with the grating 600 gr/mm or 1200 lines/mm (complete installation with a universal tripod) or similar device.

The arc generator DG-2 with optional rheostat or similar device.

Muffle furnace with thermostat at the temperature of 800−850 °C.

Microphotometer MF-2 or similar device.

Cup platinum.

Analytical scale.

Libra torsion type VT-500 or similar type.

A device for sharpening graphite electrodes.

The mortar and pestle niobium.

The mortar and pestle Plexiglas.

Electrodes graphite high purity-7−3 6 mm in diameter, sharpened to a diameter of 3.6 mm (grinding length 7 mm), hollow-sharpened part with a diameter of 2 mm, depth 4 mm.

Powder graphite brand high purity-7−4.

Photographic plates 9x12 cm type UPS for spectral analysis or similar, to ensure the normal blackening of analytical lines.

The organic glass box for sample preparation and sample comparison.

Of niobium pentoxide spectral-net.

Iron oxide on the other 6−09−5346−87, h.d. a.

Titanium dioxide, H. h

Silicon dioxide according to GOST 9428−73, h.d. a.

Cobalt (II) nitrate 6-aqueous.

Sodium chloride according to GOST 4233−77, H. h

Hydrochloric acid by the GOST 3118−77, diluted 1:1.

The technical rectified ethyl alcohol GOST 18300−87.

The developer according to GOST 10691.1−84.

Fixer: 300 g chernovetskogo sodium, 20 g of ammonium chloride according to GOST 3773−72растворяют respectively 700 and 200 cmof water, poured the resulting solutions together and the total volume was adjusted with water to 1 DM.

(Changed edition, Rev. N 1, 2).

2.2. Preparation for assay

2.2.1. Preparation of a primary reference sample (OOS) containing 2% of silicon and titanium, and 4% of iron, based on the mixture of metals.

1,3161 g of niobium pentoxide, 0,428 g of silicon dioxide, 0,0334 g of titanium dioxide and 0,0572 g of iron oxide niobium is ground in a mortar under a layer of alcohol for 1.5−2 hours (consumption of alcohol for 1 transaction 30 cm). The mixture is dried under an infrared lamp to constant weight.

(Changed edition, Rev. N 1).

2.2.2. Sample preparation comparison (OS)

The comparison samples are prepared by successive dilution of the primary reference sample, and then each subsequent sample of niobium pentoxide.

The mass fraction of each of the designated impurities in the samples comparison (in percent, calculated on the metal content of a mixture of metals) and added to the mixture sample of niobium pentoxide and diluted sample are shown in table.1.

Table 1

The mixture is ground in a mortar under a layer of alcohol for 1.5−2 hours (consumption of alcohol for 1 transaction 30 cm) and dried under an infrared lamp.

The comparison samples stored in plastic jars with lids from polyethylene.

(Changed edition, Rev. N 1, 2).

2.2.3. Preparation of a buffer mixture containing 89% of graphite powder, 10% sodium chloride and 1% cobalt oxide.

8.9 g of graphite powder and 1 g of sodium chloride was placed in a Teflon Cup, add 7 cmof a 5% strength solution of cobalt nitrate (the dry mixture should contain 1% of cobalt oxide) heat the tile at 200−300 °C until the termination of allocation of oxides of nitrogen, ground in a Styrofoam mortar for 1.5−2 hours (consumption of alcohol for 1 transaction 30 cm) and dried under an infrared lamp to constant weight.

(Changed edition, Rev. N 1, 2).

2.3. Analysis

0.5 g of shavings of niobium is washed with hydrochloric acid in a glass beaker by heating. The acid is drained, washed shavings with distilled water and alcohol (alcohol consumption 1 to 3 cm). The washed chips is placed in a platinum Cup and calcined in a muffle until constant weight, gradually raising the temperature to 800 °C. From 1 g of niobium should be 1.43 g of niobium pentoxide. Received pentoxide thoroughly mixed, take a sample mass of 100 mg and triturated in a mortar with a plexiglass 100 mg of buffer mix. Prepared samples are stuffed into the recesses of the six carbon electrodes, prebaked in an arc, AC, 10±0.5 A during 5 s. the Electrode pairs placed in the electrode holders tripod, light between arc AC and take pictures of the spectra of each pair of electrodes on the spectrograph, using the being system of the slit illumination. The index of the scale of the wavelength of the spectrograph is mounted so that a part of the spectrum around 290 nm was in the middle of the spectrogram. The arc current is maintained at 15±0,5 A. the Interelectrode distance of 3 mm, exposure time of each spectrum is 60 s. the same operations are performed with samples of comparison spectra being photographed on the same photographic plate. The spectrum of each test sample (or each sample comparison) photographed three times.

(Changed edition, Rev. N 2).

2.4. Processing of the results

Each of the obtained spectrograms with photoretrieval find the blackening of analytical lines of impurities () and element comparisons () (see table.2) and calculate the difference pucherani . On three values , , obtained three spectrograms taken for each sample, find the arithmetic mean ().

Table 2

The results of electrophoretic spectra of samples comparisons build a calibration curve in the coordinates , where is the logarithm of the mass fraction of the element in the reference sample.

Mass fraction of silicon, titanium and iron in the sample of niobium find the results of electrophoretic spectra using a calibration chart.

The difference between the largest and smallest results of the three parallel definitions should not exceed the allowable absolute values of the differences indicated in the table.3.

Table 3

If in the spectra of samples basis of comparison, there is a weak line of the element, then the construction of calibration curve, corrected for the value of the mass fraction of the element in the basis. An amendment is permissible only under the condition that this value does not exceed the specified limit for the method definition. The purity of the basis for the preparation of samples of the comparison is controlled by the spectral method (addition method).

Allowable absolute differences of the intermediate mass fraction of silicon, titanium, and iron are calculated using linear interpolation.

(Changed edition, Rev. N 1, 2).

2.5. Validation results

The analyzed sample is converted into the pentoxide of niobium according to claim 2.4. To 0.5 g of the obtained niobium pentoxide is added 0.5 g of the second reference sample (originally found the mass fraction of silicon and iron in the sample is 0.01% or less than 0.01%) or 0.5 g of the third reference sample (originally found the mass fraction of titanium, 0.005%, or less than 0.005%). The mixture is ground thoroughly in a mortar and Styrofoam under a layer of alcohol, dried under infrared lamp, and the analysis is carried out for PP.2.3; 2.4.

The analyses are correct, if the first mixture of a test sample and additives, minus half of the original mass fraction found in the sample obtained average value of (0,010±0,003)% silicon (0,020±0,004)% of iron, and the second mixture 0,005±0,002% titanium.

If the results are outside specified limits, the validation of the results of repeat tests, increasing the number of parallel definitions up to six. The obtained average values should be for the first mixture (0,010±0,002)% silicon (0,020±0,003)% of iron, and for the second mixture (0,0050±0,0015)% titanium.

(Changed edition, Rev. N 1, 2).

2.6. Check the value of control experience

To check the value of the reference experiment in the deepening of the six graphite electrodes, prebaked in an arc, AC, 10±0.5 A for 5 s, placed pentoxide of niobium or a buffer mixture and the spectra photographed under clause 2.3. In the resulting spectrograms photometric density pucherani analytical lines of silicon, titanium, iron and feature lines comparison of cobalt (see table.2). The difference between the blackening () should not exceed 0.02 units of blackening.

3. DETERMINATION of SILICON, TITANIUM, AND IRON (with a mass fraction of silicon, titanium from 0.01 to 0.15% and iron from 0.01 to 0.1%)

The method is based on the intensity of the spectral lines of silicon, titanium and iron from their mass fractions in a sample of niobium in the excitation spectrum in the arc DC.

3.1. Apparatus, materials and reagents

The quartz spectrograph ISP-30 (complete installation with a universal tripod) or similar device.

A constant current source, providing power not less than 260 V and a current not less than 20 A.

Muffle furnace with thermostat at the temperature of 800−850 °C.

Microphotometer MF-2 or similar device.

Cup platinum.

Analytical scale.

Libra torsion type VT-500 or similar type.

A device for sharpening carbon electrodes.

Electrodes of graphite brand high purity-7−4 6 mm in diameter, sharpened to a diameter of 4 mm (length of grinding 10 mm), hollow-sharpened part with a diameter of 2.4 mm and a depth of 1.5 mm (bottom).

Electrodes of graphite brand high purity-7−4 6 mm in diameter, sharpened to a diameter of 4 mm at a length of 10 mm (upper).

Powder graphite high purity-7−4.

Mortar with pestle, niobium and Plexiglas.

Photographic plates of the spectral size of 9x12 cm type I or similar type, providing a normal blackening of analytical lines.

Of niobium pentoxide spectral-net.

Iron oxide on the other 6−09−5346−87, h.d. a.

Titanium dioxide.

Silicon dioxide according to GOST 9428−73, h.d. a.

Of Nickel oxide according to GOST 17607−72 tested for purity silicon, titanium and iron according to claim 3.6.

Hydrochloric acid by the GOST 3118−77, diluted 1:1.

The technical rectified ethyl alcohol GOST 18300−87.

The organic glass box for sample preparation and sample comparison.

The developer according to GOST 10691.1−84.

Fixer: 300 g chernovetskogo of sodium and 20 g of ammonium chloride according to GOST 3773−72растворяют respectively 700 and 200 cmof water, poured the resulting solutions together and the total volume was adjusted with water to 1 DM.

(Changed edition, Rev. N 1, 2).

3.2. Preparation for assay

3.2.1. Preparation of a primary reference sample (OOS) containing 2% each of silicon, titanium and iron (based on the mixture of metals niobium, silicon, titanium, and iron).

Sample 1,3447 g of niobium pentoxide, 0,0428 g of silicon dioxide, 0,0334 g of titanium dioxide and 0,0286 g of iron oxide niobium is ground in a mortar under a layer of alcohol for 1.5−2 hours (consumption of alcohol for 1 transaction 30 cm). Grinded mixture is dried under an infrared lamp to constant weight.

3.2.2. Sample preparation comparison

Prepare serial dilution of the basic sample compare OOS (see item 3.2.1), and then each subsequent sample of niobium pentoxide.

The mass fraction of each of the designated impurities in the samples comparison (in percent, calculated on the metal content of a mixture of metals) and added to the mixture sample of niobium pentoxide and diluted sample are shown in table.4.

Table 4

The mixture is ground in a mortar under a layer of alcohol for 1.5−2 hours (consumption of alcohol for 1 transaction 30 cm) and dried under an infrared lamp.

The comparison samples stored in plastic jars with lids from polyethylene.

3.2.3. Preparation of a buffer mixture consisting of 50% graphite powder and 50% Nickel oxide.

5 g of graphite powder and 5 g Nickel oxide mixed in a mortar under a layer of alcohol for 1 h (consumption of alcohol for 1 transaction 30 cm) and dried under an infrared lamp.

3.2.1−3.2.3. (Changed edition, Rev. N 2).

3.3. Analysis

0.5 g of shavings of niobium is washed with hydrochloric acid in a glass beaker by heating on a hotplate. The acid is drained, washed shavings with distilled water and alcohol (alcohol consumption 1 to 3 cm). The washed chips is placed in a platinum Cup and calcined in a muffle until constant weight, gradually raising the temperature to 800 °C. From 1 g of niobium should be 1,430 g of niobium pentoxide. Received pentoxide thoroughly mixed, take from it a portion weighing 100 mg and triturated in a mortar with 100 mg of buffer mix. The prepared mixture was stuffed into the recesses of the bottom three electrodes, prebaked in the arc of direct current at 10±0,5 A. the Electrodes (top and bottom of sample) placed in the electrode holders of the tripod. Between the electrodes ignite the DC arc, and photographing spectra of three pairs of electrodes on the spectrograph, using the being system of the slit illumination.

The arc current is maintained at 14±0,5 A. the Interelectrode distance of 3 mm, exposure 60 s. the same operations are performed with samples of comparison spectra being photographed on the same photographic plate.

(Changed edition, Rev. N 2).

3.4. Processing of the results

Each of the obtained spectrograms with photoretrieval find the blackening of analytical lines of impurities () and element comparisons () (see table.5) and calculate the difference pucherani (). On three values , , obtained three spectrograms taken for each sample, find the arithmetic mean ().

Table 5

The results of electrophoretic spectra of samples comparisons build a calibration curve in the coordinates , where is the logarithm of the mass fraction of the element in the reference sample. Mass fraction of silicon, titanium and iron in the sample of niobium find the results of electrophoretic spectra of the analyzed sample by using a calibration chart.

The difference between the largest and smallest results of the three parallel definitions should not exceed the allowable absolute values of the differences indicated in the table.6.

Table 6

If in the spectra of samples basis of comparison, there is a weak line of the element, then the construction of calibration curve, corrected for the value of the mass fraction of the element in the basis. An amendment is permissible only under the condition that this value does not exceed the specified limit for the method definition. The purity of the basis for the preparation of samples of the comparison is controlled by the spectral method (addition method).

Allowable absolute differences of the intermediate mass fraction of silicon, titanium, and iron are calculated using linear interpolation.

(Changed edition, Rev. N 1, 2).

3.5. The analyzed sample with a mass fraction of impurities of 0.01−0.05% is converted into the pentoxide according to claim 3.3. To the suspension obtained pentoxide by weight of 0.5 g is added a portion of the second reference sample weight of 0.5 g. the Mixture is thoroughly ground in a mortar Styrofoam under a layer of alcohol (for 1 transaction spent 3 cmof ethanol), dried under infrared lamp and analyzed for PP.3.3, 3.4. Tests correct if in the mixture of the sample with the additive minus the ¾ originally found the mass fraction obtained (0,050±0,007)% silicon, titanium, iron. If the results are outside specified limits, the validation of the results of repeat tests, increasing the number of parallel definitions up to six. The obtained average values of the mass fraction of silicon, titanium, and iron should be (0,050±0,005)%.

(Changed edition, Rev. N 2).

3.6. (Deleted, Rev. N 2).