GOST 23859.1-79
GOST 23859.1−79 heat-resistant Bronze. Method for the determination of copper (with Amendments No. 1, 2)
GOST 23859.1−79
Group B59
INTERSTATE STANDARD
BRONZE HIGH-TEMPERATURE
Method for determination of copper
Bronze fire-resistance. Method for the determination of copper
AXTU 1709
Date of introduction 1981−01−01
Resolution of the USSR State Committee for standards, dated 16 October 1979, N 3937 time of the introduction set with 01.01.81
Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)
EDITION with Amendments No. 1, 2 approved in June 1985, March 1990 (IUS 9−85, 7−90)
This standard specifies a gravimetric method for the electrolytic determination of copper in high-temperature copper alloys.
The method is based on the allocation of copper by electrolysis when a current of 1.5−2.5 A, the weigh-ins evolved at the cathode precipitate of copper and determination remaining in the electrolyte of copper by atomic absorption in the flame acetylene-air at a wavelength of 324,7 nm and photometric with cuprizone.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 25086−87 with the addition of: analysis result should be the arithmetic mean of results of three (two) of parallel definitions.
(Changed edition, Rev. N 2).
2. APPARATUS, REAGENTS AND SOLUTIONS
Electrolysis installation with a source of DC power.
Platinum electrodes according to GOST 6563−75.
Drying Cabinet.
Nitric acid GOST 4461−77 diluted 1:1 and 1:100.
Sulfuric acid GOST 4204−77 and diluted 1:1 and 1:4.
Hydrofluoric acid according to GOST 10484−78.
Rectified ethyl alcohol GOST 18300−87.
Photoelectrocolorimeter or spectrophotometer.
Atomic absorption spectrometer with a lamp with a hollow cathode for copper.
Citric acid according to GOST 3652−69.
Ammonia water according to GOST 3760−79 and diluted 1:4.
Ammonium citrate solution: 150 g of citric acid dissolved in 400 cmof water, add with stirring 100 cmof concentrated ammonia, cooled, added to 100 cmof ammonia, cool and add water to 1000 cm.
Bio-cyclohexanone-oxalyl-dihydrazone (cuprizone), solution: 2.5 g cuprizone dissolved with stirring in 900 cmof water at a temperature of 60−70 °C. After cooling, the solution was filtered into a dark glass jar, top up with water to 1000 cm. The solution to fit 10 days.
Copper according to GOST 859−2001 with a mass fraction of copper not less than 99.9%.
Standard solutions of copper
Solution a: 0.5 g of copper is dissolved in 10 cmof nitric acid (1:1), and remove the oxides of nitrogen by boiling, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.
1 cmof the solution contains 0.001 g of copper.
Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.
1 cmof a solution contains 0.0001 g of copper.
(Changed edition, Rev. N 1, 2).
3. ANALYSIS
3.1. For bronzes not containing chromium
The sample of bronze with a weight of 1 g was placed in a beaker with a capacity of 250 cm, add 15 cmof nitric acid, diluted 1:1, cover with a watch glass and dissolved under heating.
After dissolution of the alloy and removal of oxides of nitrogen by boiling, the glass and the side of the Cup then rinsed with water and the solution diluted with water to 150 cm. Add 7 cmof sulphuric acid, diluted 1:4, and produce copper by electrolysis. For this purpose, the weighted solution is immersed platinum electrodes, the glass electrolyte can enjoy watch glass or organic glass with openings for electrodes and stirrer and carry out the electrolysis while stirring at a current of 1,5−2,5 A.
After the bleaching solution the side of the Cup, glass and protruding parts of the electrodes rinsed with water, add about 20 cmof water and continue the electrolysis for another 10−15 min.
If svezhemorozhenoj portion of the cathode is not allocated sediment, electrolysis is considered complete. Otherwise, the electrolysis are a few minute and again monitor the completeness of separation of copper.
After electrolysis, without turning off the current, quickly remove the beaker with the electrolyte and rinse the cathode, immersing successively in three beakers with water, then with ethyl alcohol. The cathode is dried in a drying Cabinet at 105 °C to constant weight, cooled and weighed.
One serving of alcohol (200 cm) can be used for washing no more than 20 electrodes.
(Changed edition, Rev. N 1, 2).
3.2. For bronzes containing chromium
The sample of bronze with a weight of 1 g was placed in a beaker with a capacity of 150−250 cm, add 15 cmof nitric acid, diluted 1:1, cover with a watch glass and dissolved under heating.
After dissolution of the sample and removal of oxides of nitrogen by boiling, the glass and the side of the Cup then rinsed with water and the solution diluted with water to 100 cm. The solution is kept for 10 minutes in a warm place and filter through a tight filter, filtrowanie compacted mass into a glass with a capacity of 250 cm. The filter was washed 7−8 times with hot nitric acid, diluted 1:100.
To the filtrate is added 7 cmof sulphuric acid, diluted 1:4, and produce copper by electrolysis as described in claim 3.1.
3.3. For bronzes containing chromium and silicon
The sample of bronze with a weight of 1 g was placed in a platinum Cup, pour 10 cmof nitric acid, diluted 1:1, 2−3 cmhydrofluoric acid and cover with a lid of PTFE or platinum. After dissolution, the sample solution is evaporated to a small volume. Then cooled and carefully poured 5 cmof sulphuric acid diluted 1:1, and the solution is evaporated prior to the allocation of white smoke of sulfuric acid. A Cup of cool, dissolve salt in 30−40 cmof hot water when heated, transfer the solution into a glass with a capacity of 250−300 cm, flow 10 cmof nitric acid, diluted 1:1, boil to remove oxides of nitrogen, add water up to 150 cm, and determine the copper as stated in claim 3.1
.
3.2, 3.3. (Changed edition, Rev. N 1).
3.4. Determination of residual copper in the electrolyte
The electrolyte, after separation of copper is evaporated to a volume of 80 cm, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.
3.4.1. Determination of copper by atomic absorption spectrometry
3.4.1.1. Measure the atomic absorption of copper in the flame acetylene-air at a wavelength of 324,7 nm in parallel with the solutions to construct the calibration curve.
3.4.1.2 Construction of calibration curve
In six of the seven volumetric flasks with a capacity of 100 cmis placed 0,5; 1,0; 2,0; 3,0; 4,0 and 5,0 cmstandard solution B. all of the flasks add 5 cmnitrogen (1:1) and sulfuric (1:1) acids, made up to the mark with water and measure the atomic absorption of copper, as specified in clause
3.4.2. Definition of copper by the photometric method with cuprizone
3.4.2.1. Aliquot part of the solution is 20 cmis placed in a volumetric flask with a capacity of 100 cm, add 10 cmof a solution of ammonium citrate and ammonia solution (1:4) to slightly alkaline reaction, then add 2cmof a solution of ammonia (1:4), 10 cmsolution cuprizone immediately topped up to the mark with water and mix. the pH of the obtained solution should be of 8.5−9.0 on the indicator paper. After 5 min, but not later than 30 min, measure the optical density of the solution on a photoelectrocolorimeter with an orange filter in the cell with thickness of the absorbing layer 3 cm, or on the spectrophotometer at 600 nm in a cuvette with a thickness of absorbing layer 1 cm. Solution comparison the solution serves as the reference experiment.
3.4.2.2. Construction of calibration curve
In six of the seven volumetric flasks with a capacity of 100 cmis placed 0,5; 0,75; 1,0; 1,5; 2,0 and 2,5 cmstandard solution B. all of the flasks add 5 cmof nitric acid (1:1), 10 cmof a solution of citrate of ammonium and further analysis is carried out as specified in clause
3.4−3.4.2.2. (Added, Rev. N 2).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of copper (a) in determining the remaining in the electrolyte of copper by atomic absorption spectrometry in percent is calculated by the formula
,
where is the mass of cathode, g;
— the mass of the cathode with segregated copper, g;
— the concentration of copper was found in the calibration schedule, g/cm;
— the volume of the electrolyte, cm;
— weight of sample, g
.
4.2. Mass fraction of copper (a) in determining the remaining in the electrolyte of copper by the photometric method percentage is calculated by the formula
,
where is the mass of cathode, g;
— the mass of the cathode with segregated copper, g;
— the mass of copper was found in the calibration schedule g;
— weight of sample, g;
— the volume of the electrolyte, cm;
— volume aliquote part of the solution, cm
.
4.3. Discrepancies in the results of three parallel definitions should not exceed the values of permissible differences (the rate of convergence) of 0.15%.
4.4. Discrepancies in the results analysis, obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed 0.22 percent.
4.5. Control of accuracy of analysis results is carried out according to State standard samples of heat-resistant (CR) bronze in accordance with GOST 25086−87.
Sec. 4. (Changed edition, Rev. N 2).