GOST 1293.7-83

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  ГОСТ 1293.7-83

GOST 1293.7−83 lead-antimony Alloys. Methods for determination of iron (with Amendments No. 1, 2)

GOST 1293.7−83*
______________________
* The designation of the standard.
Changed the wording, Rev. N 2.

Group B59

STATE STANDARD OF THE USSR

LEAD-ANTIMONY ALLOYS

Methods of iron determination

Lead-antimony alloys. Methods for the determination of iron

AXTU 1709*
________________

* Changed the wording, Rev. N 1.

Valid from 01.07.83
prior to 01.07.88*
_______________________________
* 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.

DEVELOPED by the Ministry of nonferrous metallurgy of the USSR

PERFORMERS

A. P. Sychev, M. G. Sun, L. I. Maksay, R. D. Kogan

INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

Member Of The Board Of A. P. Snurnikov

APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on standards of February 8, 1983 N 704

REPLACE GOST 1293.7−74

MADE: the Change in N 1, approved and put into effect by the Decree of the USSR State Committee for standards from 20.11.87 N 4205 from 01.07.88, Change No. 2 adopted by the Interstate Council for standardization, Metrology and certification (minutes N 13 dated 28.05.98). The state developer of Kazakhstan. By the resolution of Gosstandart of Russia from 11.04.2001 N 173-St introduced on the territory of the Russian Federation from 01.01.2002

Change N 1, 2 made by the manufacturer of the database in the text IUS N 2, 1988, ICS # 7, 2001

This standard establishes photometric methods for determination of iron in iron mass fraction of from 0.0005 to 0.04% in lead-antimony alloys.

(Changed edition, Rev. N 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 1293.0−83.

2. PHOTOMETRIC METHOD for determination of IRON with PHENANTHROLINE

2. PHOTOMETRIC METHOD FOR DETERMINATION OF IRON
with FENANTROLINA

2.1. The essence of the method

The method is based on the formation at a pH of 4 is colored red complex compound with the divalent iron -fenantrolina and subsequent measurement of optical density at a wavelength of 510 nm on the spectrophotometer or in a region of wavelengths 500−530 nm on a photoelectrocolorimeter.

The interfering elements are separated by cementation with lead.

(Changed edition, Rev. N 1).

2.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

Nitric acid of high purity according to GOST 11125−84 diluted 1:1 and 1:3.

The acid chloride.

Lead according to GOST 22861−93 in plates containing not more than 0,0002% of iron.

Crystalline sodium acetate according to GOST 199−78.

Acetic acid GOST 61−75, ice.

Hydroxylamine hydrochloride according to GOST 5456−79, a solution of 10 g/DM, freshly prepared.

-fenantrolin, a solution of 10 g/DM, freshly prepared.

Salt of protoxide of iron and ammonium double sulfate (salt Mora) according to GOST 4208−72.

(Changed edition, Rev. N 1, 2).

2.3. Preparation for assay

2.3.1. Preparation of a standard iron solution

Solution a: of 0.7020 g of Mohr salt dissolved in 100 cmof solution of hydrochloric acid (1:1), transferred to a volumetric flask with a capacity of 500 cm, was adjusted to the mark with water and mix.

1 cmof solution A contains 0.2 mg of iron.

Solution B: take 10 cmof solution A in a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

1 cmof the solution contains 0.02 mg of iron.

(Changed edition, Rev. N 2).

2.3.2. Preparation of buffer solution: 272 g sodium acetate and dissolve in 500 cmof water and set pH 5.5 by adding the appropriate amount of glacial acetic acid.

2.3.3. To build a calibration curve in eight of the nine volumetric flasks with a capacity of 100 cmeach measure 0,5; 1; 2; 4; 6; 8; 10 and 12 cmof solution B, which corresponds to 10, 20, 40, 80, 120, 160, 200 and 240 µg of iron. In the ninth flask solution B is added. All flasks is poured water up to 60 cm, add 10 cmbuffer solution, 2 cmof a solution of hydrochloric acid hydroxylamine and 5 cmmortar -fenantrolina, stirring after each addition of the reagent.

Solutions was adjusted to the mark with water and mix. After 30 min, measure the optical density of the solution at a wavelength of 510 nm on the spectrophotometer or in a region of wavelengths 500−530 nm on a photoelectrocolorimeter, using appropriate cuvettes.

Solution comparison is the solution not containing a standard solution of iron.

According to the obtained values of optical density of the solutions and their corresponding values of iron content to build a calibration curve.

(Changed edition, Rev. N 1)

.

2.4. Analysis

A portion of the alloy weight of 2,0000 g when the mass fraction of iron to 0.01% or 0,5000 g when the mass fraction of iron in excess of 0.01% was placed in a conical flask with a capacity of 250 cmand dissolved with slow heating in 20 cmof nitric acid (1:3), cover the flask with a watch glass. Then remove watch glass, add 15 cmof perchloric acid and boil until the volume of solution reduced to about 5 cm. Add 50 cmof water, 1 g of lead, again cover watch glass, and boil slowly for 15 min. the Solution was cooled and washed lead decantation. Then add 1 g of lead, and boil slowly for 5 minutes, If the surface of the lead changes due to the deposition of copper or of antimony, boil for another 10 min, adding a new portion of lead. The solution was decanted, the lead is washed with water and discarded. After that, the solution was filtered through a filter of medium density. The filter is washed with water, collecting filtrate and washings in a volumetric flask with a capacity of 100 cm, adding 25 cmof buffer solution, 2 cmof hydrochloric acid hydroxylamine solution, 10 cmof solution -fenantrolina. The solution was adjusted to the mark with water and mix. After 30 min measure the optical density of the solution, as mentioned in paragraph 2.3.3. Solution comparison is the solution of the reference experiment.

The mass of iron found by the calibration schedule.

(Changed edition, Rev. N

2).

2.5. Processing of the results

2.5.1. Mass fraction of iron () in percent is calculated by the formula

,

where is the mass of iron in the sample solution, found by calibration schedule, mcg;

 — volume of initial solution, cm;

 — weight alloy, g;

 — volume aliquote part of the solution, cm.

2.5.2. The discrepancy between the results of parallel measurements (the difference between the largest and smallest results of parallel measurements) and the discrepancy between the results of the analysis (the difference between the larger and the smaller of the results of the analysis) at a confidence level =0.95 does not exceed the allowable absolute values of the differences given in the table.

The control accuracy of the analysis is carried out using standard samples or by other methods stipulated by GOST 1293.0−83.

The error analysis results (at a confidence probability =0,95) does not exceed the limit values given in the table, under the following conditions: the discrepancy between the results of parallel measurements does not exceed the permissible, the results of accuracy control positive.

(Changed edition, Rev. N 2).

2.5.3. The method used in the disagreement in assessing the quality of the alloy.

3. PHOTOMETRIC METHOD FOR DETERMINATION OF IRON WITH SULFOSALICYLIC ACID

3.1. The essence of the method

The method is based on formation of yellow sulfosalicylate iron complex and subsequent measurement of its optical density at a wavelength of 420 nm on the spectrophotometer or in a region of wavelengths of 400−420 nm on a photoelectrocolorimeter. Lead pre-allocate in the form of sulphate.

(Changed edition, Rev. N 1).

3.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer

Nitric acid of high purity according to GOST 11125−84 diluted 1:1 and 1:9.

Tartaric acid according to GOST 5817−77, a solution of 500 g/DM.

Sulfuric acid GOST 4204−77, diluted 1:1.

Sulfosalicylic acid according to GOST 4478−78, a solution of 300 g/DM.

Ammonia water according to GOST 3760−79.

Salt of protoxide of iron and ammonium double sulfate (salt Mora) according to GOST 4208−72.

(Changed edition, Rev. N 1, 2).

3.3. Preparation for assay

3.3.1. Preparation of a standard iron solution

Solution a: of 0.7020 g of Mohr salt dissolved in 100 cmof solution of hydrochloric acid (1:1), transferred to a volumetric flask with a capacity of 500 cm, was adjusted to the mark with water and mix.

1 cmof solution A contains 0.2 mg of iron.

Solution B: take away 5 cmof solution A in a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

1 cmof a solution contains 0.01 mg of iron.

(Changed edition, Rev. N 2).

3.3.2. To build a calibration curve in six of the seven volumetric flasks with a capacity of 50 cmselect 1, 2, 3, 4, 5 and 6 cmstandard solution B, which corresponds to 10, 20, 30, 40, 50 and 60 µg of iron in the seventh flask solution B is added. All flasks go for 20 cmwater and 1 cmof a solution of tartaric acid, 10 cmsulfosalicylic acid solution, neutralized with ammonia solution on litmus and pour the 2 cmin excess. The volume was adjusted solution to the mark with water and mix. The optical density of solutions measured in the region of wavelengths of 400−420 nm on or photoelectrocolorimeter at a wavelength of 420 nm on the spectrophotometer. Solution comparison is the solution not containing a standard solution of iron.

According to the obtained values of optical density of the solutions and their corresponding grades of iron to build the calibration graph.

(Changed edition, Rev. N 1).

3.4. Analysis

A portion of the alloy weight of 5,0000 g when the mass fraction of iron to 0.005% or 1,0000 g when the mass fraction of iron in excess of 0.005% is placed in a conical flask with a capacity of 250 cmand dissolved with slow heating in 50 cmof nitric acid (1:1) with addition of 5 cmof a solution of tartaric acid, cover the flask with a watch glass. Then remove the watch glass, the solution was boiled to remove oxides of nitrogen. Pour 20 cmof water and transferred the solution into a measuring flask with a capacity of 100 cm. Injected 10 cmof sulphuric acid (1:1), made up to the mark with water, mixed well and allowed to settle a draught of sulphate of lead.

20 cmtransparent solution at weight ratio of iron to 0.005% and 10 cmwhen the mass fraction of iron in excess of 0.005% is transferred to a volumetric flask with a capacity of 50 cm, pour 1 cmof a solution of tartaric acid, 10 cmsulfosalicylic acid solution, neutralized with ammonia solution until alkaline reaction to litmus and pour the 2 cmin excess. The volume was adjusted solution to the mark with water and mix well. Measure the optical density of the solution as indicated in claim 3.3.2.

As a solution comparison using the solution in the reference experiment.

The mass of iron found by the calibration schedule.

(Changed edition, Rev. N 2)

.

3.5. Processing of the results

Processing of the results of the analysis carried out according to claim 2.5.