GOST 22974.7-96

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  ГОСТ 22974.7-96

GOST 22974.7−96 fused welding Fluxes. Method of determination of phosphorus

GOST 22974.7−96

Group B09

INTERSTATE STANDARD

FUSED WELDING FLUXES

Method of determination of phosphorus

Melted welding fluxes. Method of phosphorus determination

ISS 77.040
AXTU 0809

Date of implementation 2000−01−01

Preface

1 DEVELOPED by the Interstate technical Committee for standardization MTK 72; the Institute of electric them. E. O. Paton of NAS of Ukraine

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. 9 dated April 12, 1996)

The adoption voted:

3 Resolution of the State Committee of the Russian Federation for standardization and Metrology, dated April 21, 1999 N 134 inter-state standard GOST 22974.7−96 introduced directly as state standard of the Russian Federation from January 1, 2000

4 REPLACE GOST 22974.7−85

1 Scope

This standard sets the photometric method for the determination of phosphorus at a content of from 0.01 to 0.2%.

2 Normative references

The present standard features references to the following standards:

GOST 83−79 Sodium carbonate. Specifications

GOST 3118−77 hydrochloric Acid. Specifications

GOST 3760−79 Ammonia water. Specifications

GOST 3765−78 Ammonium molybdate. Specifications

GOST 4165−78 Copper (II) sulfate 5-water. Specifications

GOST 4198−75 Potassium phosphate odnosemjannyj. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 5456−79 of Hydroxylamine hydrochloride. Specifications

GOST 6344−73 Thiourea. Specifications

GOST 20490−75 Potassium permanganate. Specifications

GOST 22974.0−96 fused welding Fluxes. General requirements for methods of analysis

GOST 22974.1−96 fused welding Fluxes. Methods of flux decomposition

GOST 22974.2−96 fused welding Fluxes. Methods for determination of silicon oxide

3 General requirements

General requirements for methods of analysis GOST 22974.0.

4 Photometric method for the determination of phosphorus

4.1 the essence of the method

The method is based on the formation of phosphorus-molybdenum complex followed by the restoration of it in hydrochloric acid medium with ions of bivalent iron in the presence of hydroxylamine hydrochloride or thiourea to the complex compound, colored blue. The color intensity is measured on the spectrophotometer at a wavelength of 620−700 nm or photoelectrocolorimeter with a red light filter.

4.2 Equipment, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

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

Hydrochloric acid according to GOST 3118, diluted 1:1 with a density of 1.105 g/cm.

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

Ammonium molybdate according to GOST 3765, recrystallized according to GOST 22974.2, solution mass concentration of 0.05 g/cm.

Iron (III) nitrate 9-water, solution of the mass concentration of 0.01 g/cm.

Potassium permanganate according to GOST 20490, solution mass concentration of 0.005 g/cm.

Copper (II) sulfate 5-water according to GOST 4165, a solution of 4.5 g of copper sulphate is placed in a flask with a capacity of 3000 cmand dissolved in 500 cmof hot water.

The anhydrous sodium carbonate according to GOST 83, solution of the mass concentration of 0.01 g/cm.

Hydroxylamine hydrochloride according to GOST 5456, solution mass concentration of 0.2 g/cm.

Thiourea according to GOST 6344, solution: 170 g of thiourea was placed in a flask with a capacity of 3000 cmand dissolved in 2000 cmof hot water.

The mixture recovery: a solution of thiourea in a thin stream poured into a solution of copper sulphate and stirred. The mixture is left for two days. The precipitate is filtered through three filters. Transparent recovery mix is used for the determination of phosphorus.

Potassium phosphate according to GOST odnosemjannyj 4198, standard solutions.

Solution a: 0,4394 g of single potassium phosphate, dried over sulfuric acid to constant weight, transferred to a measuring flask with volume capacity of 1000 cm, dissolved in water and diluted to the mark with water. The solution has a mass concentration of phosphorus of 0.0001 g/cm.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix. The solution has a mass concentration of phosphorus 0,000

01 g/cm.

4.3 analysis

4.3.1 the Linkage of flux with a mass of 0.5 g was placed in a platinum crucible with lid, mixed with 5 g of sodium carbonate anhydrous and melted at a temperature of 950−1000 °C for 20−30 min. the Melt was poured onto a polished plate of stainless steel. Crucible, cover and melt is placed in a beaker with a capacity of 200−300 cm, 100 cm pourhot water, heated to 90 °C and kept at this temperature for about 1 h. the leaching of the crucible and the cover over the glass is washed with hot water. The solution is filtered on a filter «white ribbon» in a volumetric flask with a capacity of 250 cm, washed 5−6 times with hot sodium carbonate solution, the mass concentration of 0.01 g/cm. The solution in the flask was cooled, adjusted to the mark with water and mix (precipitate discarded).

4.3.1.1 When recovering phosphorus and molybdenum heteroalicyclic ions of divalent iron in the presence of hydrochloric acid hydroxylamine: 25 cmof filtrate was taken in a conical flask with a capacity of 150−200 cm, pour 3 cmof a solution of nitrate of iron mass concentration of 0.01 g/cmand fully dissolve precipitated hydroxides of the metals, adding small portions of hydrochloric acid with a density of 1.105 g/cm, add 10 cmof hydrochloric acid hydroxylamine solution and heated to boiling. The solution should be colorless.

If the solution retains a yellow color, add 1−2 drops of ammonia solution. The appearance of turbidity it is dissolved by adding 1−2 drops of hydrochloric acid with a density of 1.105 g/cm.

The flask with the solution was cooled, poured 10 cmof hydrochloric acid solution with a density of 1.105 g/cm. Then dropwise, with continuous stirring, poured 8 cmof a solution of molybdate of ammonium. The solution was stirred for 1−2 min until appearance of a blue color, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix again.

After 10 minutes measure the optical density of the solution on the spectrophotometer at a wavelength of 620−700 nm or photoelectrocolorimeter with a red light filter in the cell thickness of the absorbing layer is 50 mm.

As a solution comparison using the solution in the reference experiment, conducted through the whole course of Ana

Lisa.

4.3.1.2 When recovering phosphorus and molybdenum heterophilically with thiourea: 25 cmof filtrate was taken in a volumetric flask with a capacity of 100 cm, add water to 50 cm, pour 3 cmof a solution of nitrate of iron mass concentration of 0.01 g/cmand fully dissolve precipitated hydroxides of the metals, adding small portions of hydrochloric acid with a density of 1.105 g/cm. After perelivania solution of hydrochloric acid the solution becomes transparent, but retains a brown color and after 10−15 minutes brightens. Then pour 10 cmof hydrochloric acid solution with a density of 1.105 g/cmin excess. Add a 10 cmrestoration mix, allow to stand until complete discoloration of the solution. Then dropwise, with continuous stirring, pour 5 cmof ammonium molybdate. The solution was stirred 1−2 min until the appearance of blue color, made up to the mark with water and mix.

After 10 minutes measure the optical density of the solution on the spectrophotometer at a wavelength of 620−700 nm or photoelectrocolorimeter with a red light filter in the cell thickness of the absorbing layer is 50 mm. as a solution comparison using the solution of the control experiment conducted using the whole analysis.

A lot of find phosphorus for the calibration graph

the IR.

4.3.2 For fluxes that do not contain titanium oxide (IV)

After the decomposition flux according to GOST 22974.1 aliquot part of the solution is 25 cmis placed in a conical flask with a capacity of 100−150 cm, flow 10 cmof a solution of potassium permanganate (if the decomposition of the flux produced by alloying) to break up the gelatin. The solution was heated to decolouration of potassium permanganate, add 3 cmof a solution of nitrate of iron mass concentration of 0.01 g/cm, ammonia dropwise until precipitation of hydroxides of metals and dissolved 1−2 drops of hydrochloric acid with a density of 1.105 g/cm. Then — according to 4.3.1.1 or 4.3.1.2.

4.4 Construction of calibration curve

In ten volumetric flasks with a capacity of 100 cmmaking 1,0; 2,0; 4,0; 8,0; 12,0; 16,0; 20,0; 24,0; 28,0 and 32.0 cmstandard solution B, which corresponds to 0,00001; 0,00002; 0,00004; 0,00008; 0,00012; 0,00016; 0,00020; 0,00024; 0,00028 and 0,00032 g of phosphorus. In the eleventh flask introduce 20 cmof water. Add 3 cmof a solution of nitrate of iron mass concentration of 0.01 g/cm, is neutralized with ammonia prior to the selection of iron hydroxide, which is dissolved by adding drops of hydrochloric acid with a density of 1.105 g/cm, and then — according to 4.3.1.1 or 4.3.1.2. Solution comparison is the solution in the flask containing standard solution of phosphorus.

4.5 Processing of results

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

, (1)

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

 — the weight of the portion of the flux corresponding to aliquote part of the solution,

4.5.2 Standards of accuracy and standards for monitoring the accuracy of determining the mass fraction of phosphorus are given in table 1.


Table 1

Percentage