GOST 6674.1-96

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  ГОСТ 6674.1-96

GOST 6674.1−96 copper phosphorous Alloys. Methods for determination of phosphorus

GOST 6674.1−96

Group B59

INTERSTATE STANDARD

COPPER PHOSPHOROUS ALLOYS

Methods for determination of phosphorus

Copper-phosphorous alloys.
Methods for determination of phosphorus

ISS 77.120.30
AXTU 1709

Date of introduction 2001−07−01

Preface

1 DEVELOPED by the Interstate technical Committee for standardization MTK 107; Donetsk state Institute of non-ferrous metals (Danism)

SUBMITTED to the State Committee of Ukraine for standardization, Metrology and certification

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 10 dated 3 October 1996)

The adoption voted:

3 Resolution of the State Committee of the Russian Federation for standardization and Metrology dated December 19, 2000 N 384-St inter-state standard GOST 6674.1−96 introduced directly as state standard of the Russian Federation from July 1, 2001

4 REPLACE GOST 6674.1−74

1 Scope

This standard specifies the gravimetric and photometric methods for the determination of phosphorus at its content of from 5% to 14% in the copper-phosphorous alloys.

2 Normative references

The present standard features references to the following standards:

The Copper GOST 859−78. Stamps*
_______________
* On the territory of the Russian Federation GOST 859−2001, here and hereafter. — Note the manufacturer’s database.

GOST 1277−75 Silver nitrate. Specifications

GOST 3118−77 hydrochloric Acid. Specifications

GOST 3652−69 citric Acid monohydrate and anhydrous. Specifications

GOST 3760−79 Ammonia water. Specifications

GOST 3765−78 Ammonium molybdate. Specifications

GOST 3773−72 Ammonium chloride. Specifications

GOST 4198−75 Potassium phosphate odnosemjannyj. Specifications

GOST 4209−77 Magnesium chloride 6-water. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 5712−78 Ammonium oxalate 1-aqueous. Specifications

GOST 6344−73 Thiourea. Specifications

GOST 6674.0−96 copper phosphorous Alloys. General requirements for methods of analysis

GOST 18300−87 ethyl rectified technical. Specifications

GOST 20490−75 Potassium permanganate. Specifications

3 General requirements

General requirements — according to GOST 6674.0.

4 Gravimetric method

4.1 the essence of the method

The method is based on measuring the mass of precipitate of magnesium pyrophosphate after its calcination to constant weight.

4.2 Reagents and solutions

Nitric acid according to GOST 4461 and diluted 1:1.

Hydrochloric acid according to GOST 3118 and diluted 1:1 and 1:99.

Citric acid according to GOST 3652, a solution of 500 g/DM.

Ammonium chloride (ammonium chloride) according to GOST 3773, solution 100 g/DM.

Magnesium chloride (magnesium chloride) according to GOST 4209.

A mixture of magnesia: a solution of 55 g of crystalline magnesium chloride and 105 g of ammonium chloride in 1 DMof water.

Ammonia water according to GOST 3760, diluted 1:1 and 1:9.

Silver nitrate (silver nitrate) GOST 1277, a solution of 10 g/DM.

4.3 analysis

4.3.1 the sample of alloy weighing 0.5 g of bring in a glass with a capacity of 300 cm, is dissolved in 20 cmof nitric acid solution, transferred to a porcelain Cup, add 10 cmof hydrochloric acid and evaporated on a boiling water bath to dryness. To the dry residue add 5 cmof hydrochloric acid and evaporated under the same conditions. The residue is dried at a temperature of (130±5) °C. To the dried residue add 5 cmof nitric acid, 5 cmof hydrochloric acid and 50 cmof hot water. The solution was transferred to a beaker with a capacity of 300 cm. If upon dissolution of the remainder is allocated silicic acid, the beaker content was filtered through filter «blue ribbon». In this case the precipitate is washed with hot dilute hydrochloric acid (1:99) to the disappearance of the reaction of copper (control is carried out with dilute ammonia (1:1) by the reaction of formation of the ammonia complex of copper, a solution which has a deep blue color).

To the obtained solution was added 10 cmof the citric acid solution, 20 cmof ammonium chloride solution and 25 cmof magnesia with

MESI.

4.3.2 the solution was added gradually with stirring ammonia, diluted 1:1, before the formation of the ammonia complex of copper blue. The solution is thoroughly stirred with a glass rod touching the walls of the glass prior to the discharge of sediment. Then pour the excess diluted ammonia (1:1) in number, constituting a part of the volume content of the glass, and left overnight.

4.3.3 solution and the precipitate was filtered through filter «blue ribbon» by washing the precipitate with diluted ammonia (1:9). The filter cake is dissolved in 10 cmhot dilute hydrochloric acid (1:1) and washed the filter 3−5 times with hot dilute hydrochloric acid (1:99), collecting the filtrate and washings in a beaker, which held an initial deposition of phosphorus.

To the obtained hydrochloric acid solution was added 10 cmof a solution of ammonium chloride, 5 cmof magnesia mixture, diluted to 100 cmwith water and then do as specified in 4.3.2.

4.3.4 the beaker Content was filtered through filter «blue ribbon», the precipitate washed with dilute ammonia (1:9), disappearance of reaction on chloride ions (the control is carried out using silver nitrate). Dried at 105 °C in a desiccator, the precipitate together with the filter placed in preheated and weighed crucible, the filter is incinerated, and then calcined to constant weight at a temperature of (1100±20) °C.

At the same time spend control experience.

4.4 Processing of results

4.4.1 the Content of phosphorus , %, is calculated by the formula

, (1)

where is the mass of the calcined precipitate of magnesium pyrophosphate from a sample of the alloy, g;

 — weight of the calcined precipitate of magnesium pyrophosphate in a control experiment, g;

0,2783 — the ratio of pyrophosphate of magnesium on the phosphorus;

 — the weight of the portion of alloy,

4.4.2 Discrepancy between the results of two parallel determinations should not exceed permissible value (at p = 0.95), equal to 0.10%.

4.4.3 the Discrepancy of the two results of the analysis of the same sample obtained at different times by different performers, shall not exceed the permissible value (at p = 0.95), 0.20%.

5 Photometric method

5.1 the essence of the method

The method is based on measurement at a wavelength of 570 nm optical density of the solution formed in the presence of thiourea phosphorus-molybdenum complex (molybdenum blue).

5.2 the Instrument, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

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

Potassium permanganate (potassium permanganate) according to GOST 20490, solution 20 g/DM.

Ammonium oxalate (ammonium oxalate) according to GOST 5712, a solution of 25 g/DM.

Hydrochloric acid according to GOST 3118, diluted 1:2.

Rectified ethyl alcohol (ethanol) according to GOST 18300 and diluted 5:8.

Ammonium molybdate (ammonium molybdate) according to GOST 3765, recrystallized from alcoholic solution, a freshly prepared solution 50 g/DM. The recrystallization of ammonium molybdate is carried out as follows: 70 g of drug is dissolved in 400 cmof water when heated to 70−80 °C and filtered twice with a hot solution through the same filter of «blue ribbon». To the solution add 250 cmof ethanol. The solution was cooled and allowed to settle for 1 h. the Precipitated crystals filtered off using a suction, sucking the solution and repeat the recrystallization. After filtration the crystals are washed 2−3 times with ethanol, diluted 5:8, portions of 20 to 30 cm. After this they are dried in the air.

Thiourea according to GOST 6344, solution 100 g/DM.

Potassium phosphate odnosemjannyj (monokaliy) according to GOST 4198.

Preparation of a standard solution of phosphorus: 8,7874 g monokaliy (previously dried at 105 °C to constant weight) was placed in a volumetric flask with a capacity of 1 DM, is dissolved in water, made up to the mark with water and mix.

1 cmstandard solution contains 0.002 g of phosphorus.

Copper according to the GOST 859.

5.3 analysis

5.3.1 a sample of alloy weighing 0.1 g was placed in a conical flask with a capacity of 250 cm, dissolved in 20 cmof a solution of nitric acid and boil to remove oxides of nitrogen.

5.3.2 Add 5 cmof potassium permanganate solution and kept warm on the stove until the complete coagulation of manganese oxide (IV). Add dropwise a solution of ammonium oxalate until the precipitate has fully dissolved. In order to avoid an excess of ammonium oxalate after adding each drop of its solution is thoroughly mixed.

The solution was cooled, transferred to a volumetric flask with a capacity of 200 cm, adjusted to the mark with water and mix thoroughly.

5 cmof solution is placed in a volumetric flask with a capacity of 100 cm, 12 cm is addeddiluted hydrochloric acid (1:2), 10 cmof solutions of thiourea and ammonium molybdate. All the reagents poured slowly with constant stirring. Bring to mark with water and mix again. The sample is ready for analysis.

5.3.3 For construction of calibration curve six conical flasks with a capacity of 250 cmis placed 0.1 g of copper, add 2,0; 3,0; 4,0; 5,0; 6,0 and 7,0 cmstandard solution phosphorus and dissolved by adding to each flask at 20 cmof a solution of nitric acid, boil to remove oxides of nitrogen and then act as specified in 5.3.2.

5.3.4 after 15 min after preparation, measure the optical density of the sample solution and solutions for constructing the calibration curve on photoelectrocolorimeter at a wavelength of 570 nm in a cuvette with a layer thickness of 20 mm.

Solution comparison is water.

According to the obtained results build a calibration curve in coordinates «optical density of the solution is the mass of phosphorus corresponding to aliquote part of the solution». Mass fraction of phosphorus in the sample is determined according to the calibration schedule.

5.3.5 allowed to set mass fraction of phosphorus by comparison. To do this, along with the analysis of the sample analyzing the sample comparison 5.3.1 and 5.3.2, which is used as a standard sample with a similar phosphorus content.

5.4 processing of the results

5.4.1 Mass fraction of phosphorus , %, is calculated by the formula

, (2)

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

 — the weight of the portion of alloy, suitable aliquote part of the sample solution,

5.4.2 When using the method of comparison of mass fraction of phosphorus , %, is calculated by the formula

, (3)

where  — mass fraction of phosphorus in the reference sample, %;

the value of optical density of the analyzed solution;

 — the weight of the portion of the reference sample corresponding to aliquote part of the sample solution, g;

 — the value of the optical density of the solution of the comparison;

 — the weight of the portion of alloy, suitable aliquote part of the sample solution,

5.4.3 the differences between the results of parallel measurements and the results of the analysis shall not exceed allowable values in accordance with 4.4.2 and 4.4.3.