GOST 3240.9-76
GOST 3240.9−76 magnesium Alloys. Methods for determination of lanthanum (Change No. 1)
GOST 3240.9−76
Group B59
INTERSTATE STANDARD
MAGNESIUM ALLOYS
Methods for the determination of lanthanum
Magnesium alloys.
Methods for determination of lanthanum
ISS 77.120.20
AXTU 1709
Date of introduction 1978−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of aviation industry of the USSR
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. INTRODUCED FOR THE FIRST TIME
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Item number |
| GOST 8.315−97 |
2.5 |
| GOST 199−78 |
3.2 |
| GOST 804−93 |
2.2, 3.2 |
| GOST 3118−77 |
2.2, 3.2 |
| GOST 3240.0−76 |
1.1 |
| GOST 4478−78 |
3.2 |
| GOST 4919.1−77 |
3.2 |
| GOST 5457−75 |
2.2 |
| GOST 6344−73 |
3.2 |
| GOST 22867−77 |
2.2 |
| GOST 25086−87 |
2.5 |
5. Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)
6. EDITION with Change No. 1, approved in June 1987 (IUS 11−87)
This standard sets flame photometric method for the determination of lanthanum (for the mass concentration of lanthanum from 0.5 to 2%) and photometric method for the determination of lanthanum (for the mass concentration of lanthanum 0.2 to 2%).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 3240.0.
2. FLAME PHOTOMETRIC METHOD FOR THE DETERMINATION OF LANTHANUM
2.1. The essence of the method
The method is based on measuring the intensity of molecular bands of lanthanum monoxide with piping at 794 and 743 nm excited in an acetylene-air flame. The quenching of emission of oxides of lanthanum in the presence of magnesium-zinc inhibit the introduction into the ammonium nitrate solution.
2.2. Apparatus, reagents and solutions
Spectrophotometer fiery.
Hydrochloric acid according to GOST 3118, diluted 1:1.
Ammonium nitrate according to GOST 22867, solution, prepared as follows: 600 g of reagent was dissolved with heating in distilled water and dilute with water to 1 DM.
Primary magnesium ingots according to GOST 804 in the form of chips.
A solution of magnesium 50 g/DM: 50 g of magnesium was dissolved in 800 cm
of hydrochloric acid and dilute with water to 1 DM
.
A standard solution of lanthanum: 2,345 g calcined at 600 °C for 2 h and cooled in the desiccator chemically pure oxide of lanthanum, transferred to a conical flask with a capacity of 400 cm, and dissolved in 100 cm
of solution of hydrochloric acid, the solution transferred to a volumetric flask with a capacity of 1 DM
, dilute to the mark with water and mix.
1 cmof the solution contains 0.002 g of lanthanum.
Acetylene in cylinders GOST 545
7.
2.1, 2.2. (Changed edition, Rev. N 1).
2.3. Analysis
2.3.1. A sample of alloy weighing 1 g is transferred to a conical flask with a capacity of 100 cm, is dissolved in 15 cm
of hydrochloric acid, add 15 cm
of ammonium nitrate solution, transferred to a volumetric flask with a capacity of 50 cm
, is diluted to the mark with water, mix thoroughly, introduced into the spray flame spectrophotometer and record the spectral band of an oxide of lanthanum 743 nm or 794 nm. By measuring the height of peaks of an oxide of lanthanum, find the content of lanthanum on schedule, built for the calibration solutions. The slope of the calibration graphs periodically (every four samples) check calibration solutions.
2.3.2. Five volumetric flasks with a capacity of 100 cmis administered at 40 cm
of a solution of magnesium, and 30 cm
of ammonium nitrate solution, 0; 5,0; 10,0; 15,0; 20,0 cm
standard solution lanthanum, which corresponds to 0; 0,010; 0,020; 0,030; 0,040 g of lanthanum. The solutions were topped up to the mark with water, mixed, injected into the capillary of the spray and record the intensity of the bands of lanthanum monoxide. According to the measurement results build a calibration curve.
(Changed edition, Rev. N 1).
2.4. Processing of the results
2.4.1. Mass fraction of lanthanum () in percent is calculated by the formula
where is the mass of lanthanum was found in the calibration schedule g;
— the weight of the portion of the sample,
(Changed edition, Rev. N 1).
2.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.1.
Table 1
| Mass fraction of lanthanum, % |
The absolute allowable difference, % |
| From 0.5 to 1.0 |
0,03 |
| SV. 1,0 «2,0 |
0,06 |
2.5. Control of measurement accuracy
To control the accuracy of measuring the mass fraction of lanthanum from 0.5 to 2% using the state standard samples of magnesium alloys, as well as industry standard samples and standard samples of the enterprise of magnesium alloys, issued in accordance with GOST 8.315. Accuracy control measurement is carried out in accordance with GOST 25086.
Allowed to control the accuracy of measuring the mass fraction of lanthanum by the method of additions.
(Added, Rev. N 1).
3. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF LANTHANUM
3.1. The essence of the method
Lanthanum forms, arsenazo III complex compound at a pH of 3.0−3.5, painted in crimson red color. To eliminate the interfering effect of iron, copper and alumina introduced thiourea and sulfosalicylic acid. To bind the zirconium in the complex add phenylarsonic acid. The optical density measured on photocolorimeter or spectrophotometer at 
3.2. Apparatus, reagents and solutions
A spectrophotometer of the type CFD-2 or SF-4A or type photoelectrocolorimeter FEK-56.
Hydrochloric acid according to GOST 3118, diluted 1:1 and 1% solution.
Primary magnesium ingots according to GOST 804 in the form of chips.
A solution of magnesium 1 g/DM: 1 g of magnesium metal is dissolved in 60 cm
of hydrochloric acid and add water to 1 DM
.
Indicator pentameters, 0,1% solution; prepared and stored according to GOST 4919.1.
Arsenazo, III, 0,04% solution.
Thiourea according to GOST 6344, 5% solution.
Sulfosalicylic acid according to GOST 4478, 20% solution.
Oxalic acid, saturated solution and 3% solution.
Fenilalanina acid, 5% solution.
Sodium acetate according to GOST 199, 50% solution.
A standard solution of lanthanum.
Lanthanum chloride LaCl·7H
O solution; prepared as follows: 2,6738 g of salt dissolved in 40−50 cm
of hydrochloric acid diluted 1:1, transferred into a volumetric flask with a capacity of 1 DM
, added 100 cm
of hydrochloric acid diluted 1:1, cooled, adjusted to the mark with water and mix thoroughly.
The titer of the solution set oxalate gravimetric method as follows: 10 cmof solution is placed in a glass, evaporated on the plate almost to dryness, add 40 cm of a
1% solution of hydrochloric acid, is brought almost to the boil, add 30 cm
hot solution of oxalic acid, thoroughly stirred with a glass rod and the solution with the precipitated sludge leave until the next day. The precipitate is then filtered through filter «blue ribbon» and washed with 3% cold solution of oxalic acid. The precipitate is filter-dried, calcined at 950 °C for 1 h, cool and weigh the precipitate. The ratio of lanthanum oxide to lanthanum 0,8529.
The solution contains 1 mg of lanthanum
1 cm.
3.3. Analysis
3.3.1. A sample of alloy weighing 1 g (in mass fraction of lanthanum is less than 1.5%) and 0.5 g (when concentration of lanthanum 1.5%) is dissolved in 40 cmof dilute hydrochloric acid by heating.
The resulting solution was transferred to volumetric flask with a capacity of 250 cm, is diluted to the mark with water and mix. If necessary, part of the solution is filtered off, taken aliquot part of 1 cm
in a volumetric flask with a capacity of 100 cm
and diluted with water to 30−40 cm
. Poured to a solution of 2.0 cm
of a solution of thiourea, the solution is then kept for 3−4 min and add 5 cm
sulfosalicylic acid solution, 5 cm
solution phenylarsonic acid, then add 5−6 drops of indicator and neutralize with a solution of sodium acetate until the disappearance of the pink color. Then pour 5 cm
of arsenazo III, diluted to the mark with water, mix and measure the optical density of the solution at
The content of lanthanum is determined by the calibration count
the IR.
3.3.2. Construction of calibration curve
In a series of volumetric flasks with a capacity of 250 cmadministered 0; 2,0; 4,0; 6,0; 8,0; 10,0; 12,0; 14,0; 16,0; 18,0 and 20.00 cm
of a standard solution of lanthanum, which corresponds to 0; 0,002; 0,004; 0,006; 0,008; 0,010; 0,012; 0,014; 0,016; 0,018 and 0.020 g of lanthanum, is added to 30 cm
of a hydrochloric acid solution, made up to the mark with water and mix.
Selected aliquots of 1 cmin a volumetric flask with a capacity of 100 cm
, is diluted with water to approximately 20−30 cm
, up to 4 cm
of a solution of magnesium and further analysis is carried out as specified in clause
(Changed edition, Rev. N 1)
.
3.4. Processing of the results
3.4.1. Mass fraction of lanthanum () in percent is calculated by the formula
where is the mass of lanthanum was found in the calibration schedule g;
— volume of initial solution, cm
;
— volume aliquote part of the solution, cm
;
— the weight of the portion of alloy,
(Changed edition, Rev. N 1).
3.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.2.
Table 2
| Mass fraction of lanthanum, % |
The absolute allowable difference, % |
| From 0.2 to 0.5 |
0,02 |
| SV. Of 0.5 «to 0.9 |
0,03 |
| «To 0.9» to 2.0 |
0,05 |
3.5. Control of measurement accuracy
Accuracy control measurement is carried out according to claim 2.5.
(Added, Rev. N 1).
