GOST 13938.4-78
GOST 13938.4−78 Copper. Methods for determination of iron (with Amendments No. 1, 2, 3, 4)
GOST 13938.4−78
Group B59
INTERSTATE STANDARD
COPPER
Methods of iron determination
Copper.
Methods for determination of iron
AXTU 1709
Date of introduction 1979−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
G. P. Giganov, E. M. Peneva, A. A. Blyahman, E. D. Shuvalov, A. N. Savelieva
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. REPLACE GOST 13938.4−68
4. The standard conforms to ISO 1812−76
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Section number, paragraph |
| GOST 3118−77 |
2.2 |
| GOST 3760−79 |
2.2 |
| GOST 3773−72 |
2.2 |
| GOST 4204−77 |
2.2 |
| GOST 4329−77 |
2.2 |
| GOST 4461−77 |
2.2; 3.2 |
| GOST 4478−78 |
2.2 |
| GOST 5457−75 |
3.2 |
| GOST 9849−86 |
3.2 |
| GOST 11069−74 |
2.2 |
| GOST 11125−84 |
3.2 |
| GOST 13938.1−78 |
1 |
6. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)
7. REPRINT (November 1999) with Amendments No. 1, 2, 3, 4, approved in December 1979, April 1983, June 1985, April 1988 (IUS 2−80, 7 to 83, 8−85, 7−88)
This standard specifies the photometric (with a mass fraction of from 0.0005 to 0.1%) and atomic absorption (at a mass fraction of 0.0008 to 0.06%) methods for determination of iron in copper.
(Changed edition, Rev. N 4).
1. GENERAL REQUIREMENTS
General requirements for methods of analysis and safety requirements when performing tests according to GOST 13938.1.
Sec. 1. (Changed edition, Rev. N 4).
2. PHOTOMETRIC METHOD for determination of IRON (at mass fraction of iron from 0.0005 to 0.1%)
2.1. The essence of the method
The method is based on formation of yellow complex compound of iron with sulfosalicylic acid in an ammonia solution, after separation of iron from copper deposition it with aluminum hydroxide or lanthanum. Optical density of the solution is measured at a wavelength of 425 nm.
2.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer with all accessories.
Centrifuge with all accessories.
Nitric acid according to GOST 4461.
Hydrochloric acid according to GOST 3118, diluted 1:1.
Ammonia water according to GOST 3760, diluted 1:19.
Aljumokalievyh alum (aluminum — potassium sulphate) according to GOST 4329.
Primary aluminium GOST 11069*, grade A 999 or 995.
________________
* On the territory of the Russian Federation GOST 11069−2001. — Note the CODE.
A solution of aluminum is prepared as follows: 1 g of aluminium is dissolved in 15−20 cmof hydrochloric acid and 20 g of potassium aluminum sulfate dissolved in water with the addition of 15 cm
of hydrochloric acid. Solutions top up with water to 1 DM
.
Oxide of lanthanum.
Shestibalny lanthanum nitrate or lanthanum chloride.
A solution of lanthanum; prepared as follows: 1.2 g of lanthanum oxide dissolved in 15 cmof hydrochloric acid diluted 1:1, or 2.7 g of lanthanum chloride, or 3.1 g of lanthanum nitrate dissolved in water, add 10 cm
of hydrochloric acid diluted 1:1. Solution top up with water to 1 DM
.
1 cmof the solution contains 1 mg of lanthanum.
Sulfuric acid according to GOST 4204, diluted 1:4.
Sulfosalicylic acid according to GOST 4478, solution 100 g/DM.
Ammonium chloride according to GOST 3773, a solution of 200 g/DM.
Iron restored.
Iron oxide in the NTD, previously dried at 110 °C.
The standard iron solution.
Solution A, prepared as follows: 0,143 g of iron oxide or 0,100 g of iron dissolved in 30 cmof hydrochloric acid diluted 1:1, when heated. The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM
and topped to the mark with water.
1 cmof the solution contains 0.1 mg of iron.
Solution B is prepared as follows: 20 cmsolution And transferred with a pipette into a measuring flask with a capacity of 100 cm
, add 2 cm
of hydrochloric acid diluted 1:1 and top up with water to the mark.
1 cmof the solution contains 0.02 mg of iron.
(Changed edition, Rev. N 2, 4).
2.3. Analysis
2.3.1. Definition of iron in the mass fraction it from 0.0005 to 0.01%
A sample of copper with a mass of 1.0 g was placed in a beaker with a capacity of 250 cm, and dissolved in 5 cm
of nitric acid. Nitrogen oxides can be removed by careful boiling in a beaker covered with a watch glass. The solution is diluted with 25 cm
of water, add 5 cm
of a solution of aluminum or lanthanum, then with constant stirring, a solution of ammonia in such quantity that all the copper went to the compound (blue solution). Solution and the precipitate is heated to 70−80 °C and maintained at this temperature for 20 min. After cooling, the hydroxide is separated by filtration or centrifugation.
For centrifuging the contents of the beaker were transferred to a centrifuge tube and centrifuging for 2 min. Then the solution above the precipitate is drained (sivunirmut), and the residue in the tube washed with two times 10 cmwith a solution of ammonia, diluted 1:19, each time draining the flushing solution. To the residue in the test tube and add 2cm
of hot hydrochloric acid, diluted 1:1, and after dissolution of the precipitate add 10 cm
of water. Then under stirring added dropwise a solution of ammonia until the precipitation of the hydroxide. After 10 minutes the contents of tubes tsentrifugirujut and the solution above the precipitate is drained. The residue in the tube washed with two times 10 cm
of ammonia, diluted 1:19, dissolved in 5 cm
of hydrochloric acid diluted 1:1, and the solution was transferred to a beaker, in which was conducted the deposition.
When filtering the contents of the glass after deposition of the hydroxide is filtered on a filter of medium density. The filter cake was washed several times with hot solution of ammonia, diluted 1:19. The precipitate is then washed from the filter with a jet of hot water into the Cup, which was held a deposition, add 5 cmof hydrochloric acid and the contents of the beaker is heated to dissolve the precipitate (the solution should be transparent). Solution into the beaker cool, add 25 cm
of water and periostat hydroxide ammonia solution.
The precipitate of hydroxide is filtered on the same filter and washed on the filter 5−6 times a hot ammonia solution, diluting 1:19. Then the precipitate from the filter washed with hot water into a glass, which conducted the deposition. The remainder of the hydroxide on the filter was dissolved in 5−10 cmof sulphuric acid, diluted 1:4, and collect the solution in the beaker in which the precipitated hydroxide. The filter was washed 2−3 times with small portions of hot water, adding the washings to the main solution in the beaker.
The solution was evaporated to 2−3 cmand after cooling is poured into a measuring flask with a capacity of 25 cm
or 50 cm
. The glass is washed with a solution of ammonium chloride, 2 times 5 cm
. To the solution in the volumetric flask, add 2.5 cm
of a solution of sulfosalicylic acid, mix; add 5 cm
of ammonia solution and add water to the mark. Optical density of the solution is measured within 30 min at a wavelength of 425 nm in a cell with optimal layer thickness. Solution comparison in the measurement of optical density is water.
At the same time carried out two test experience with all the applied reagents. The average value of the optical density of solutions of control experiments is subtracted from the value of the optical density of the analyzed solution.
Weight of iron in the solution set of the calibration schedule, constructed as described in section
(Changed edition, Rev. N 4).
2.3.2. Definition of iron in the mass fraction it from 0.01 to 0.1%
Dissolution and separation of iron perform in the same way as described in section of hydrochloric acid diluted 1:1, and the solution transferred to a volumetric flask with a capacity of 50 cm
and then filled to the mark with water, 5 cm
of this solution was transferred by pipette into a measuring flask with a capacity of 25 cm
, add 10 cm
of a solution of ammonium chloride, 2.5 cm
sulfosalicylic acid solution, mix, add 5 cm
of ammonia solution and add water to the mark. Next, do the same as shown in clause
2.3.3. Construction of calibration curve
In the glasses put on 0; 0,5; 1,0; 2,0; 3,0; 4,0 and 5.0 cmstandard solution B, which corresponds to 0; 10; 20; 40; 60; 80 and 100 mcg of iron, add 5 cm
of nitric acid and 25 cm
of water. The separation of iron, dissolution of the hydroxide with hydrochloric acid and measuring the optical density of the solutions perform as specified in claim
On the found values of optical density of the solutions and the corresponding content of iron to build the calibration graph.
3. ATOMIC ABSORPTION METHOD for determination of IRON (at mass fraction of iron 0.0008 up 0.06%)
3.1. The essence of the method
The method is based on dissolving the samples in nitric acid and subsequent measurement of the absorption of the iron line with the introduction of hydrochloric acid or nitric acid solution in the flame acetylene-air at a wavelength of 248.3 nm.
When the mass fraction of iron to 0,002% of its Coosada hydroxide of lanthanum.
(Changed edition, Rev. N 4).
3.2. Apparatus, reagents and solutions
Spectrophotometer, atomic absorption, comprising a lamp with a hollow cathode made of iron, burner flame acetylene-air and spray system.
Acetylene according to GOST 5457.
Air compressor.
Water bidistilled.
Nitric acid of high purity according to GOST 11125, diluted 1:1, or nitric acid according to GOST 4461 (boiled to remove oxides of nitrogen), diluted 1:1.
Copper, standard sample for spectral analysis N 312 according to the Register of N 2 containing 6,8·10% iron, or electrolyte copper is established with a mass fraction of iron.
Iron according to GOST 9849.
The standard iron solution.
Solution A, prepared as follows: 0,100 g of iron dissolved in 10 cmof nitric acid, diluted 1:1, the solution was transferred to volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix.
1 cmof the solution contains 0.1 mg of iron.
Solution B is prepared as follows: 10 cmof solution A is placed in a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof the solution contains 0.01 mg of iron.
(Changed edition, Rev. N 4).
3.3. Analysis
3.3.1. A sample of copper with a mass of 1.0 g was placed in a conical flask with a capacity of 100 cmand dissolved in 10 cm
of nitric acid, diluted 1:1. The solution was transferred to volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix. The resulting copper solution sprayed into the flame and measure the absorbance at a wavelength of 248.3 nm.
At the same time conducting follow-up experience with all the applied reagents. The value of the optical density of the solution in the reference experiment is subtracted from the value of the optical density of the analyzed solution.
Weight of iron in solution is determined by the calibration schedule.
Allowed to determine the mass fraction of iron to use the addition method.
(Changed edition, Rev. N 2).
3.3.1 a. When the mass fraction of iron to 0.002% of a sample of copper with a mass of 1.0 g was placed in a beaker or conical flask with a capacity of 250 cmand dissolved in 10−15 cm
of nitric acid, diluted 1:1, and further analysis is carried out according to claim
The solution was evaporated to a volume of 6−8 cm, cooled, placed in a volumetric flask with a capacity of 25 cm
, is diluted to the mark with water and mix.
Measure the absorption of the iron line at a wavelength of 248.3 nm, by introducing the solution into the flame acetylene-air.
Weight of iron determined by the calibration schedule.
Allowed in the sample solution determination of zinc (at a mass fraction of from 0.0005 to 0,006%), Nickel (at a mass fraction of from 0.1 to 0.5%), tin (with a mass fraction of from 0.005 to 0.06%).
(Added, Rev. N 4).
3.3.2. Construction of calibration curve
In a volumetric flask with a capacity of 100 cmis placed 1.0 g of a standard sample of copper pour 10 cm
of nitric acid, diluted 1:1. After dissolution of copper in the volumetric flask is placed 0; 0,5; 1; 2; 5; 10; 20 and 50 cm
standard solution B, made up to the mark with water and mix.
The resulting solutions contain 7; 12; 17; 27; 57; 107; 207 and 507 µg of iron.
Measure the absorbance of the solutions prepared as described in section 3.3.
According to the obtained values of optical density of solutions and their corresponding grades of iron to build the calibration graph.
When plotting the signal value of the background solution must be subtracted from the signal of each standard solution and conduct a chart from the origin.
(Changed edition, Rev. N 2, 4).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of iron () in percent by photometric determination calculated by the formulas:
when the mass fraction of iron from 0.0005 to 0.01%
when the mass fraction of iron from 0.01 to 0.1%
where is the mass of iron was found in the calibration schedule, mcg;
— the weight of the portion of copper, g;
— the volume of the analyzed solution, cm
;
— volume aliquote part of the analyzed solution, cm
.
4.2. Mass fraction of iron () in the percentage of atomic-absorption determination is calculated by the formula
where is the mass of iron was found in the calibration schedule, mcg;
— weight of copper,
4.3. Discrepancies in the results of two parallel definitions, and the two results of the analysis shall not exceed the values given in the table.
| Mass fraction of iron, % |
The absolute maximum discrepancy, %, results | |
| parallel definitions |
tests | |
| To from 0,0005 0,0010 incl. |
0,0002 |
0,0003 |
| SV. 0,0010 «0,0030 « |
0,0004 |
About 0.0006 |
| «0,003» 0,010 « |
0,001 |
0,002 |
| «0,010» 0,030 « |
0,002 |
0,005 |
| «0,030» 0,100 « |
0,004 |
0.007 |
(Changed edition, Rev. N 4).
4.4. The differences in the assessment of mass fraction of iron by the photometric method used.
(Added, Rev. N 4).
APP. (Deleted, Rev. N 4).
