GOST 26958-86

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  ГОСТ 26958-86

GOST 26958−86 Lead for the production of red lead of high purity. Method of determination of vanadium, cobalt, manganese and chromium (with Change No. 1)

GOST 26958−86

Group B59

STATE STANDARD OF THE USSR

LEAD FOR THE PRODUCTION OF RED LEAD OF HIGH PURITY

Method of determination of vanadium, cobalt, manganese and chromium

Lead for high-purity red lead production. Method for determination of vanadium, cobalt, manganese and chromium

AXTU 1709

Date of introduction 1987−07−01

INFORMATION DATA

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

DEVELOPERS

G. I. Ivanov, L. K. Larin, N. With. Belenkova, N. G. Khodyakov, G. N. Sivkova

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 15.07.86 N 2126

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. The expiration time limit is removed by the Resolution of Gosstandart of the USSR from 08.04.92 N 375

6. The re-release (may 1997) with amendment No. 1, approved in April 1992 (IUS 7−92)


This standard specifies the chemical-spectral method of determination of vanadium, cobalt, manganese and chromium in the lead for the production of red lead of high purity used in the optical melting, in the range of mass fraction: cobalt is from 1·10to 1.6·10%; vanadium, manganese and chromium from 2.5·10to 4·10% each.

The method is based on the separation of the main mass of lead in the form of nitrate compounds, the deposition of impurities together with the lead sulphate and spectrographic analysis of the resulting concentrate in the arc of DC on diffraction spectrograph of the DFS-8.

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 22306 with the addition of

1.1.1. Control of the correctness of the results of the analysis carried out by the method of additions at least once a month, and every time you replace reagents and solutions, after long interruptions and other changes that affect the results of the analysis.

The amount of additives chosen close to the mass fraction of impurities.

Determination of the mass fraction of the component in the sample with the addition of three batches. The arithmetic mean value of results of parallel measurements taken for the mass fraction of this component in the sample with the additive. Found the amount Supplement find the difference between the found mass proportions of this component in the sample with the additive and the sample without additive.

The discrepancy between the highest and lowest results of parallel measurements of the component in the sample with the additive should not exceed the values standardized in the method of analysis.

The tests are considered valid if the value found additives different from the entered values were no more than where and  — the permissible discrepancy of the results of the two analyses for the sample with additive and without additive, respectively.

(Changed edition, Rev. N 1).

1.2. Safety requirements — according to GOST 22518.1 with the addition of

1.2.1. The concentration of impurities and all operations for the preparation of samples comparisons and the preparation of samples for analysis is carried out in boxes of organic glass.

(Changed edition, Rev. N 1).

2. APPARATUS, MATERIALS AND REAGENTS

The diffraction type spectrograph DFS-8 with grille 600 or 1200 lines/mm (first order) being the illumination system of the slit.

The three — and nine-reliever.

The arc generator is adapted to ignite the DC arc high frequency discharge.

Generator DC arc providing a voltage of at least 200 V and a current not less than 20 A.

Microphotometer designed to measure pucherani spectral lines.

Spectromancer of PS-18.

Analytical scale, allows to weigh with an accuracy of 0.0002 g. more

The infrared lamp of any type with capacity up to 500 W with a laboratory autotransformer type CTL-250−2 or similar.

Hot plate heating according to GOST 14919.

Muffle furnace, allowing you to adjust the temperature to 700 °C.

Grinding machine graphite electrodes of the type CP-35, or any other type.

Boxes of organic glass.

Mortar with pestle made of organic glass.

Knife tantalum or titanium.

Glassware volumetric laboratory glass according GOST 1770.

Ware quartz.

Libra torsion bar type W or similar with a weighing error of no more than 0.001 g.

Electrodes high purity graphite with a diameter of 6 mm with the size of the crater in a 4x4 mm, pre-baked in the arc AC or DC power 10−12 And 10−15 s. Contradictory graphite, sharpened to a truncated cone with ground diameter of 1.5−2.0 mm.

Funnel and stick the Plexiglas to transfer sample into the crater of the electrode.

References to build calibration curve prepared according to the application.

The graphite powder of high purity according to GOST 23463.

Nitric acid of high purity according to GOST 11125 and solutions 1:2 and 1:1.

Sulfuric acid of high purity according to GOST 14262 and a solution of 1:1.

Acetic acid according to GOST 61, a solution with a mass concentration of 30 g/DM.

Distilled water according to GOST 6709, is further distilled in a quartz apparatus.

Photographic plates «spectrographic» types I and II or SFC-02, the SFC-03.

Type I load in the cassette for the spectrum 310,0-to 350.0 nm, type II — for the shorter wavelengths.

Developer a metol-hydrochinone consisting of two solutions which, before manifestation, are mixed in the ratio 1:2.

Allowed to use a developer and fixer of a different composition. The time of development of photographic plates 5 min at developer temperature of 18−20 °C.

Pipettes with a capacity of 1, 2, 5, 10, 20 cm.

Note. Allowed the use of devices with photoelectric registration of spectrum and other spectrographic equipment and facilities other materials and reagents, subject to obtaining accuracy rate no worse than specified in this standard.

(Changed edition, Rev. N 1).

3. ANALYSIS

A sample of lead with a mass of 10 g is cut into pieces 50−500 mg and placed in a conical flask with a capacity of 250−300 cm. Pour 20 cmof acetic acid, stirred vigorously, the acid is drained and washed 2−3 times with water at 15−20 cm. Lead is dissolved by heating (quartz flasks closed with watch glass) of 50 cmof a solution of nitric acid 1:2. After complete dissolution of the mass of sample solution brought to a boil and pour 50 cmof boiling nitric acid in equal portions four times with vigorous stirring (the acid is previously boiled to remove oxides of nitrogen).

Precipitate nitrate of lead.

The contents of the flask was boiled down to 90−80 cm(label on the flask) and cooled in running water for 40−50 min. the Solution was poured into a quartz Cup with a capacity of 100 cm. The precipitate is washed twice with nitric acid at 15 cm, carefully mixing. After settling, the wash solution was decanted into the Cup with the basic solution and evaporated under a lamp to a volume of 2−3 cm. The walls of the Cup is washed with 10 cmof water, which completely dissolved the precipitate, add 1.0 to 1.5 cmof sulfuric acid solution. The contents of the cups was evaporated under a lamp and then on a hotplate until the termination of allocation of steams of sulphur dioxide and calcined in a muffle furnace for 30 minutes at a temperature of 550 °C. the Mass of concentrate shall not be less than 200 mg. If the mass of concentrate obtained less then add up to 200 mg remaining amount of lead sulfate that is used as the basis for the preparation of samples comparison. Calculated enrichment coefficient according to the formula

,

where is the mass of the obtained concentrate of impurities mg.

At the same time through the entire course of the analysis are controlling experience for inclusion in the analyses adjusted for purity of the reagents and the conditions of experience. To do this in a conical flask with a capacity of 250−300 cmpoured all reagents required for the dissolution of lead, deposition and separation of its nitrate (as enrichment sample). The contents of the flask is evaporated, poured into a quartz Cup. The walls of the flask is washed with 10 cmof water. The solution is evaporated under the lamp 2−3 cm. Add a Cup of 200 mg of lead sulphate (the basis for the preparation of samples comparison) and 1.0−1.5 cmof sulfuric acid solution.

The contents of the Cup is evaporated under a lamp or on the stove until the termination of allocation of steams of sulphur dioxide and calcined in a muffle furnace at 550 °C for 30 min.

The concentrate of the impurities of the sample, the reference experiment and the comparison samples are mixed with graphite powder in a ratio of 5:1 to 100 mg is placed through a funnel into the crater prebaked graphite electrode and compacted with a stick of Plexiglas. The spectra photographed using a three-step attenuator on the type of spectrograph DFS-8 in the arc of a DC power of 15 And twice. The width of the slit of a spectrograph 0,015 mm. exposure Time 1 min (to burnout, plus 10). Each sample enriched in three batches.

(Changed edition, Rev. N 1).

4. PROCESSING OF THE RESULTS

In the spectrogram, using microphotometry measure the intensity of the blackening of analytical lines of the determined elements and the surrounding background (wavelengths in nm):

vanadium 318,4

cobalt — 345,3

manganese — 279,4

302,1 chrome or chrome 427,4.

According to the measured pochernenija, using the characteristic curve of photographic plates, find the intensity of the line and the intensity of the background and build the calibration graphs in the coordinate , ,

where is the intensity of the line with accounting background;

 — mass fraction of impurities in the samples comparison, %.

According to the calibration schedule find the mass percent of impurities in the concentrate samples () and the concentrate control experience ().

Mass fraction of impurities in the sample lead () in percent is calculated by the formula

,

where is the enrichment coefficient of the sample;

the enrichment coefficient in the reference experiment.

The final result of the analysis be the arithmetic mean of results of three parallel measurements (each simultaneous determination of the two spectrograms).

The value of the results of the analysis are rounded and expressed with two significant digits.

Permissible discrepancies in the results of parallel measurements and the results of two tests at a confidence level =0.95 does not exceed the values given in the table.

Permitted discrepancies for the intermediate mass fraction calculated using linear interpolation.

(Changed edition, Rev. N 1).

APP (mandatory). PREPARATION OF SAMPLES FOR CONSTRUCTING THE CALIBRATION GRAPHS

APP
Mandatory

The basis for the preparation of samples for constructing the calibration graphs is sulphate of lead, derived from lead of high purity grades S0000 or S000 GOST 22861. Lead dissolved in nitric acid 1:2 with heating (quartz flasks closed with watch glass). After complete dissolution of the entire mass of the sample precipitated in the form of lead sulfate compounds by adding sulfuric acid or its solution 1:1. The solution is decanted from the precipitate and discarded. The precipitate is twice washed with water, dried and calcined in a muffle furnace at a temperature of ~550 °C for 40−60 min.

Sulphate of lead is stored in a plastic container with a screw cap.

Standard solutions

Standard solutions of vanadium: 0,0895 g VOon the other 6−09−1948−78 placed in a beaker with a capacity of 100 cm, add 10 cmof nitric acid, heated and add 10 cmof hydrogen peroxide according to GOST 10929 (in portions of 2−3 cm) until complete dissolution of the mass of sample. After cooling, the solution was quantitatively transferred to a volumetric flask with a capacity of 100 cm, add 20 cmof nitric acid and bring to mark with water.

1 cmof solution A contains 0.5 mg of vanadium.

20 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, add 20 cmof nitric acid and bring to mark with water.

1 cmof a solution contains 0.1 mg of vanadium.

10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, add 20 cmof nitric acid and bring to mark with water.

1 cmof the solution contains 0.05 mg of vanadium.

Standard solutions of manganese: 0,050 g of metallic manganese according to GOST 6008помещают in a glass with a capacity of 100 cmand dissolved in 5 cmof nitric acid solution 1:1. After dissolution, the total mass of the sample solution is heated to boiling to remove the oxides of nitrogen, cooled and quantitatively transferred to a volumetric flask with a capacity of 100 cm. Bring to mark with water.

1 cmsolution G contains 0.5 mg of manganese.

20 cmsolution G is transferred to a volumetric flask with a capacity of 100 cm, add 5 cmof nitric acid solution 1:1 and adjusted to the mark with water.

1 cmof solution e contains 0.1 mg of manganese.

10 cmsolution G is transferred to a volumetric flask with a capacity of 100 cm, add 5 cmof nitric acid solution 1:1 and adjusted to the mark with water.

1 cmof solution E contains 0.05 mg of manganese.

Standard solutions of chromium: 0,0731 g chromological ammonium (NH)CDFaccording to GOST 3774 placed in a beaker with a capacity of 50 cmand dissolved in 10−15 cmof water. After dissolution of the entire mass of sample solution is quantitatively transferred to a volumetric flask with a capacity of 100 cmand adjusted to the mark with water.

1 cmW solution contains 0.5 mg of chromium.

20 cmsolution W is transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water.

1 cmof solution Z contains 0.1 mg of chromium.

10 cmof a solution S is transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water.

1 cmof the solution contains 0.05 mg of chromium.

Standard solutions of cobalt: 0,050 g of metallic cobalt GOST 123* placed in a beaker with a capacity of 100 cmand dissolved by heating in 10 cmof nitric acid solution 1:1. The resulting solution was heated to boiling to remove the oxides of nitrogen, cooled and transferred quantitatively into a measuring flask with a capacity of 100 cm. Bring to mark with water.
______________
* On the territory of the Russian Federation GOST 123−2008. — Note the manufacturer’s database.

1 cmof solution contains 0.5 mg of cobalt.

10 cmsolution is transferred To volumetric flask with a capacity of 100 cm, add 5 cmof nitric acid solution 1:1, adjusted to the mark with water.

1 cmL of the solution contains 0.05 mg of cobalt.

20 cmof the solution L is transferred to a volumetric flask with a capacity of 100 cm, add 5 cmof nitric acid solution 1:1, adjusted to the mark with water.

1 mM solution contains 0.01 mg of cobalt.

The solutions can be stored for 2−3 months. If necessary, they are analyzed by atomic absorption or chemical methods.

Sample preparation comparison: in quartz Cup is placed a portion basis weight of 10 g, moisten it with 1−2 cmof water, add the solutions in accordance with the table, dried under an infrared lamp, then on the hotplate and calcined in a muffle furnace at 550 °C for 1 h.

The resulting mass of each sample was mixed thoroughly with quartz pestle and stored in buksh or plastic jars with screw lids.

(Changed edition, Rev. N 1).