GOST 11930.8-79

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  ГОСТ 11930.8-79

GOST 11930.8−79 Materials surfacing. Method for the determination of phosphorus (with Amendments No. 1, 2)

GOST 11930.8−79

Group B09

INTERSTATE STANDARD

MATERIALS SURFACING

Method of determination of phosphorus

Hard-facing materials. Method of phosphorus determination

ISS 25.160.20
AXTU 1709

Date of introduction 1980−07−01

The decision of the State Committee USSR on standards on March 21, 1979 N 982 date of introduction is established 01.07.80

Limitation of actions taken by Protocol No. 4−93 of the Interstate Council for standardization, Metrology and certification (ICS 4−94)

REPLACE GOST 11930−66 in part of sec. 6

EDITION (August 2011) with Amendments No. 1, 2 approved in December 1984, December 1989 (IUS 3−85, 3−90)


This standard establishes photocolorimetric method for the determination of phosphorus (at a mass fraction of phosphorus from 0.02 to 0.3%) in the surfacing materials.

The method is based on formation of colored complex compounds of the molybdophosphoric heterophilically with selenology orange.

(Changed edition, Rev. N 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 11930.0−79.

2. APPARATUS, REAGENTS AND SOLUTIONS

Photoelectrocolorimetry brands FEK-56, FEK-M or any other type.

Nitric acid GOST 4461−77 diluted 1:1.

Potassium hydroxide or sodium hydroxide according to GOST 4328−77, a solution with a mass fraction of 20%.

Ammonium molybdate according to GOST 3765−78, a solution with a mass fraction of 10%.

Ammonium disodium phosphate according to GOST 3772−74.

Standard solutions:

solution a is prepared by dissolving in water 0,426 g of the reagent in a volumetric flask with a capacity of 500 cmand dilute to the mark with distilled water.

1 cmof the solution contains 0.0002 g of phosphorus;

solution B is prepared as follows: 1 cmof solution A is diluted with distilled water in a volumetric flask with a capacity of 100 cm.

1 cmof solution B contains 0,000002 grams of phosphorus.

Selenology orange aqueous solution with a mass fraction of 0.1%. Prepared the day before work.

Reagent pre-check on the suitability of the reaction of formation of the complex with the molybdophosphoric heteropolyacid: 10 cmof acetone is added 0.1 cm(3−4 drops) of 0.1% kylinalove orange. If the solution remains colorless or has laboratoi staining reagent suitable for analysis, if the color purple, the reagent complex by the molybdophosphoric heteropolyacid is formed.

(Changed edition, Rev. N 1, 2).

3. ANALYSIS

3.1. Phosphorus is determined in the filtrate obtained after separation of the silicon GOST 11930.3−79.

Of volumetric flasks with a capacity of 200 cmtake 10−25 cmof the analyzed solution in a beaker with a capacity of 100 cm. Solution into the beaker to neutralize the Congo by the alkaline solution and poured 20 cmin excess. The beaker with the precipitate is heated to boiling, cooled and transferred to a volumetric flask with a capacity of 100 cm, is diluted to the mark with water and mix. Part of the solution filtered through a dry filter into a dry beaker.

Depending on the phosphorus content of the selected 5−20 cmof the filtered solution in a volumetric flask with a capacity of 100 cm, neutralize Congo nitric acid, diluted 1:1, add 10 cmof nitric acid in excess and dilute with water to 80 cm. Then add 10 cmof a solution with a mass fraction of 10% ammonium molybdate and leave for 10 min for the formation of the molybdophosphoric heteroalicyclic. Then the flask was injected 5 cmof solution with a mass fraction of 0.1% kylinalove orange, dilute to the mark with water and mix. The solution is kept for 45 min for formation of stable complex compounds. After 45 min, measure the optical density of colored solutions on a photoelectrocolorimeter with a green filter (540 nm) in a cuvette with a thickness of the absorbing layer is 50 mm.

At the same time spend three reference experiment for the determination of phosphorus reagents. Solution with the average value of phosphorus content in the reagents is used as a solution of comparison.

3.2. Construction of calibration curve

To construct calibration curve take from 0.5 to 3 cmstandard solution dosagedosage ammonium phosphate (solution B) with an interval of 0.5 cmin a volumetric flask with a capacity of 100 cm, is added to 10 cmof nitric acid, diluted 1:1 and dilute the solution in the flask to about 80 cmwater. Then add 10 cmof a solution with a mass fraction of 10% ammonium molybdate and leave for 10 min to develop the color of heteroalicyclic. Next add 5 cmof solution with a mass fraction of 0.1% kylinalove orange, diluted to the mark with distilled water, mixed well and left for 45 min for formation of stable colored compounds. After a specified time, measure the optical density of colored solutions on a photoelectrocolorimeter with a green filter (540 nm) in a cuvette with a thickness of the absorbing layer is 50 mm.

As a solution comparison solution is used in the reference experiment (average of three parallel to the phosphorus content in the reagents).

3.1, 3.2. (Changed edition, Rev. N 2).

4. PROCESSING OF THE RESULTS

4.1. Mass fraction of phosphorus () in percent is calculated by the formula

,

where is the mass of phosphorus was found in the calibration schedule g;

 — aliquota part acid solution analyzed, ml;

 — the mass of sample, g;

 — aliquota part of the analysis of the alkaline solution, cm.

4.2. The difference between the largest and smallest results of the three parallel measurements, and the two results of the analysis at a confidence level of 0.95 does not exceed the permissible differences given in the table.

(Changed edition, Rev. N 2).