GOST 1293.15-90

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  ГОСТ 1293.15-90

GOST 1293.15−90 lead-antimony Alloys. Spectrographical method for determination of Nickel

GOST 1293.15−90

Group B59

STATE STANDARD СОЮ3А SSR

LEAD-ANTIMONY ALLOYS

Spectrographical method for determination of Nickel

Antimonous lead alloys. Spectrographical method for determination of nickel

AXTU 1709

Valid from 01.01.91
up to 01.01.2001*
_______________________________
* Expiration removed by Protocol No. 7−95
The interstate Council for standardization,
Metrology and certification (I & C N 11, 1995). -
Note the manufacturer’s database.

INFORMATION DATA

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

DEVELOPERS

A. P. Sychev, doctor of engineering. Sciences; A. B. Mineev, L. K. Larina, T. I. Treskova

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from 26.02.90 N 267

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard sets the spectrographic method for the determination of Nickel from 0.0005 to 0.005% of lead-antimony alloys.

The method is based on converting lead-antimony alloy in sulfuric acid salt, followed by spectrographic determination of Nickel in the arc mode on the quartz spectrograph of the ISP-30.

1. GENERAL REQUIREMENTS

1.1. Sampling and preparation for analysis — according to GOST and GOST 1292 24231.

1.2. General requirements for method of analysis according to GOST 25086 with the Supplement.

1.3. The analysis result should be the arithmetic mean of two parallel definitions, each of which receive the three spectrograms on a single photographic plate.

2. SAFETY REQUIREMENTS

2.1. When performing tests, it is necessary to comply with the safety requirements according to GOST 1293.0 with additions.

2.1.1. All devices used for the spectral analysis of lead-antimony alloys, must be equipped with devices for grounding according to GOST 12.2.007.0 and GOST 12.1.030 and grounded in accordance with electrical codes adopted by the Glavgosenergonadzora.

2.1.2. To prevent entering the working area of hazardous substances in quantities exceeding the maximum allowable concentration according to GOST 12.1.005, and for protection from electromagnetic radiation and burns by ultraviolet rays, each a source of excitation spectra should be placed inside of the device, equipped with an integrated exhaust air inlet according to GOST 12.4.021 and protective screen according to GOST 12.1.019.

2.1.3. Control of content of harmful substances in the air of the working area must be performed according to GOST 12.1.007, GOST 12.1.005 and GOST 12.1.016.

2.1.4. Machine used for grinding graphite electrodes must have a built-in exhaust air inlet.

2.1.5. Preparation of samples for analysis (dissolution, evaporation, and the taking of test portions, grinding, gasket carbon electrodes) must be in the pits, equipped with built-in exhaust air terminals.

2.1.6. Permissible noise levels on workplaces should correspond to GOST 12.1.003. Monitoring of noise level at the workplace of laboratory facilities is carried out according to GOST 12.1.050.

2.1.7. Laboratory facilities of spectral analysis must conform to the rules for arrangement and maintenance of laboratories and points of spectral analysis.

3. APPARATUS, MATERIALS AND REAGENTS

Spectrograph with quartz optics medium variance type of ISP-30 being the illumination system of the slit. Allowed the use of devices with photoelectric registration of spectrum and other spectrographic devices, certified in accordance with GOST 8.326*, subject to obtaining the metrological characteristics are not worse than specified in this standard.
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* On the territory of the Russian Federation are PR 50.2.009−94**
** PR 50.2.009−94 abrogated on the basis of the order of the Ministry of industry and trade of 30.11.2009 N 1081. — Note the manufacturer’s database.

Arc generator of alternating current.

Generator DC arc providing a voltage of at least 200 V and a current not less than 15 A.

Microphotometer of any type, allowing to measure the density of the blackening of analytical lines.

Spectromancer of any type.

Analytical scale and torsion with a weighing error of no more than of 0.0002 and 0.001 g, respectively.

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

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

Mortar with pestle, agate, Jasper or plexiglass.

Cup porcelain vypaivali according to GOST 9147 with a capacity of 50−250 cm.

Graphite electrodes 6 mm in diameter with a crater size of 4x4 mm with a transverse through hole at the bottom of the crater with a diameter of 0.7 mm (prepared electrodes are fired in the arc AC or DC power 10 A for 10 s).

Contradictory graphite, sharpened to a truncated cone with ground diameter of 1.5−2.0 mm.

Powder graphite obtained from graphite electrodes.

Photographic plates «spectrographic» type 1.

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

Solution 1

Solution 2

Fixer is acidic.

Hot plate heating according to GOST 14919.

Nitric acid according to GOST 4461, diluted 1:3.

Sulfuric acid according to GOST 4204, diluted 1:1.

Funnel and a punch of Plexiglas for moving the sample in the crater of the electrode and sealing its.

Alloy lead-antimony GOST 1292 with a mass fraction of Nickel less than 0.0001%.

Nickel GOST 849*, mark N-0.
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* On the territory of the Russian Federation GOST 849−97. — Note the manufacturer’s database.

Sodium chloride according to GOST 4233 and a solution with a mass fraction of 20%.

4. PREPARATION FOR ASSAY

4.1. The basis for the preparation of samples of comparison is sulphate of lead, derived from lead-antimony alloy with a mass fraction of Nickel less than 1·10%. Pieces of alloy with a mass of 50−500 mg, shavings or sawdust placed in a porcelain Cup and washed free from surface contamination into the solution of nitric acid (1:3) for 30 s and distilled water. The prepared alloy is dissolved in nitric acid solution (1:3) with moderate heat under the watch glass. If significant evaporation of the solution add 5−10 cmof water to prevent the precipitation of nitrate of lead. After complete dissolution of the alloy is precipitated lead sulfate by the gradual addition of sulfuric acid solution until complete precipitation of the lead. The solution is decanted and discarded, leaving the sediment. The precipitate is twice washed with water, dried and calcined in a muffle furnace at a temperature of ~550 °C for 1 h. Sulfuric acid lead stored in a plastic container with a screw cap.

4.2. Standard solutions of Nickel (1 mg/cm) is prepared as follows: 0.1 g of Nickel dissolved in 15 cmof nitric acid (1:3) and transferred to a volume of 100 cm. In the preparation of a standard solution it is possible to use a Nickel salt. If necessary, the prepared solution is analyzed by atomic absorption or photometric method according to GOST 1293.13.

4.3. Samples of comparison is prepared as follows: in a porcelain Cup with a capacity of 50 cmis placed a portion basis weight g 9,995, moisten it with 1−2 cmof water, add 5 cmof a standard solution of Nickel, dried on the hotplate and calcined in a muffle furnace at a temperature of ~550 °C for 1 h. the resulting core sample containing 0.05 percent Nickel, is ground in a mortar.

Method serial dilutions of the primary sample 10 times, and each newly prepared in 2−2,5 times is preparing a series of working samples comparison. In the diluent base obtained according to claim 4.1.

References containing 0,0050; 0,0025; 0,0010; 0.0005% of Nickel stored in buksh or other tightly sealed container.

4.4. The buffer mixture was prepared by adding graphite powder in 2% sodium chloride in a salt or solution.

Of the sample and standard samples mixed with buffer in a ratio of 7:1.

5. ANALYSIS

5.1. Pieces, shavings or sawdust of lead-antimony alloy with a mass of 1−2 g was placed in a porcelain Cup, washed with a solution of nitric acid (1:3) and water and is dissolved in 30−40 cmof nitric acid (1:3) by slow heating under the watch glass. If significant evaporation of the solution add 5−10 cmof water to prevent the precipitation of nitrate of lead. After dissolution of the alloy is added in small portions ~10 cmof sulfuric acid solution until complete precipitation of lead sulfate. The solution above the precipitate was evaporated on a hotplate until the termination of allocation of steams of sulfuric acid and calcined in a muffle furnace for 30 minutes at a temperature of ~550 °C.

The obtained salt is ground in a mortar, mixed with buffer in a ratio of 7:1 and is transmitted to spectral analysis.

From each sample selected for analysis for two sample.

5.2. Sample of the prepared samples and comparison samples weighing 100 mg were placed in the craters of graphite electrodes, compacted with a punch and photographed in the arc of DC power And 15 photographic plates of type 1 (three spectrum for each reference sample and each sample of the sample).

The slit width of the spectrograph of the ISP-30 is 0.017 mm, the exposure time of 95 s.

6. PROCESSING OF THE RESULTS

6.1. On microphotometer measure the blackening of analytical lines of Nickel 305,08 nm and the background () from the side of long waves. The calibration graphs are built in coordinates , where is the arithmetic mean of the three values
,  — mass fraction of Nickel in the samples of the comparison in percent. According to the obtained values on a schedule determined by the mass fraction of Nickel in the sample. The final result of the analysis should be the arithmetic mean of two parallel definitions (each definition of the three spectrograms). The discrepancy between the results of parallel measurements (the rate of convergence) at a confidence level shall not exceed allowable absolute differences calculated by the formula

,

where is the General relative standard deviation of convergence equal to 0.08;

 — the arithmetic mean of the results of parallel measurements;

 — the critical importance of scale sampling normal population, equal to 2.77 for and .

The discrepancy between the two results of the analysis of the same sample (a measure of reproducibility) shall not exceed the allowable absolute differences calculated by the formula

,

where is the General relative standard deviation of reproducibility equal to 0.10;

 — the average of the two results of the analysis.

7. CONTROL OF ACCURACY OF ANALYSIS RESULTS

7.1. Control of accuracy of analysis results is carried out by additives or by comparing the analysis results with the results obtained by another independent method, at least once a month, and also when replacing the reagents, after the repair spectrographic setup, after a long break in work and other changes that affect the results of the analysis.

7.1.1. The amount of additives should be two times less or match the mass fraction of the element in the analyzed sample. The additive (solution of Nickel) is introduced before the dissolution of samples of the alloy in nitric acid.

The results of the analysis are believed to be accurate, if the found value differs from the additive introduced its value of not more than 0.71, where and  — the permissible discrepancy of the results of the analysis of samples without additive and with additive, respectively.

7.1.2. For control of accuracy using the methods in accordance with GOST 1293.13 or certified according to GOST 8.505 and with the error not exceeding the error-controlled methods of analysis.

The results of the analysis of samples believed to be accurate, if , where and  — the permissible discrepancy between the results of the sample analysis control and controlled spectrographic methods.