19014.1 GOST-73
GOST 19014.1−73 Silicon crystal. Methods for determination of aluminium (with Amendments No. 1, 2, 3)
GOST 19014.1−73*
Group B59
STATE STANDARD OF THE USSR
SILICA, CRYSTALLINE
Methods for determination of aluminium
Crystal silicon. Methods of aluminium determination*
______________
* The name of the standard. Changed the wording, Rev. N 3.
AXTU 1709
Date of introduction 1975−01−01
The decision of the State Committee of standards of Ministerial Council of the USSR from July 23, 1973 N 1804 the introduction of set with 01.01.75
Proven in 1984 by the Resolution of Gosstandard dated August 15, 1984, 2874 N validity extended to 01.01.90**
________________
** Expiration removed by Protocol No. 4−93 of the Interstate Council for standardization, Metrology and certification (I & C N 4, 1994). — Note the manufacturer’s database.
REPLACE GOST 2178−54 in part of sec. III
* REISSUE (November 1985) with Amendments No. 1, 2 approved in July 1979, August 1984 (IUS 8−79, 11−84)
AMENDED N 3, approved and put into effect from
Change No. 3 made by the manufacturer of the database in the text IUS N 11, 1989
This standard specifies the titrimetric and atomic absorption methods for the determination of aluminum (with a mass fraction of aluminum from 0.30 to 1.60%) in crystalline silicon.
(Changed edition, Rev. N 3).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 19014.0−73.
1a. TITRIMETRIC METHOD
The essence of the method consists in removing the silicon in the form of tetrafluoride in the separation of titanium and iron hydroxides. Aluminium determined by chelatometric method, titrating the excess Trilon B solution of nitrate of zinc with selenology orange indicator at pH=5,5.
Section 1A. (Added, Rev. N 3).
2. REAGENTS AND SOLUTIONS
Hydrofluoric acid according to GOST 10484−78.
Nitric acid GOST 4461−77.
Sulfuric acid GOST 4204−77, diluted 1:1.
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Sodium hydroxide according to GOST 4328−77, a solution with a mass fraction of 20%.
Potassium preservatory according to GOST 7172−76.
Zinc metal according to GOST 3640−79*.
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* On the territory of the Russian Federation GOST 3640−94. — Note the manufacturer’s database.
Standard solution of zinc nitrate solution with molar concentration of 0.05 mol/l; prepared as follows: 3,269 g of zinc was dissolved with heating in a mixture of 100 cm
water and 15 cm
of nitric acid. The solution was evaporated to 5−10 cm
and dilute with water to 1000 cm
.
Ammonia water according to GOST 3760−79.
Sodium acetate according to GOST 199−78.
Acetic acid GOST 61−75.
Acetate buffer solution; prepared as follows: 250 g of crystalline sodium acetate are placed in a measuring flask with volume capacity of 1000 cm, dissolved in water, add 20 cm
of acetic acid, adjusted to the mark with water and mix.
Selenology orange solution with a mass fraction of 0.1%.
The solution is valid within 10 days.
Trilon B (III chelating agent, disodium salt of ethylenediaminetetraacetic acid) according to GOST 10652−73, solution with molar concentration of 0.05 mol/l; prepared as follows: 18.6 g Trilon B dissolved in water; filtered into a measuring flask with volume capacity of 1000 cm
, is diluted to the mark with water and mix thoroughly.
To determine the correction factor solution with a molar concentration of 0.05 mol/DMTrilon B taken from burette 20 cm
of the solution Trilon B in a conical flask with a capacity of 500 cm
and dilute with water to 200 cm
. Add 5−6 drops of orange kylinalove and ammonia drop by drop until blue coloration that can be eliminated by adding dropwise hydrochloric acid, diluted 1:1, before the appearance of yellow color. Then the flask was poured 20 cm
of acetate buffer solution and titrated with a solution of zinc nitrate until the color changes from yellow to pink.
The correction factor for the solution with molar concentration of 0.05 mol/DMTrilon B (
) is calculated by the formula
where is the number of solution with molar concentration of 0.05 mol/DM
nitric acid zinc, cm
;
— the number of solution Trilon B, cm
.
If the control for the experience of taking the same amount of solution Trilon B, as for the samples, a correction factor for solution of Trilon B can not be determined.
Sodium carbonate according to GOST 83−79.
Sodium tetraborate 10-water according to GOST 4199−76, dehydrated at 400 °C.
Mix for fusion: mix sodium carbonate and sodium tetraborate in a ratio of 6:1 (by weight).
(Changed edition, Rev. N 2, 3).
3. ANALYSIS
3.1. A portion of the silicon mass of 2 g is placed in a platinum Cup with a capacity of 200 cm, moisten with water, add 30 cm
hydrofluoric acid, and then small portions of 15 cm
of nitric acid.
Careful rotation stirred the contents of the Cup. At the end of the violent reaction of the walls of the Cup and rinse with water, add 5 cmof sulphuric acid diluted 1:1, and evaporated in the bath until white fumes of sulphuric acid anhydride. Then cooled, carefully washed the walls of the Cup with water from prominance and evaporated on steam bath to dryness.
To the dry residue add 5 g of potassium peacemaking and fused in a muffle at 800 °C or dry residue fused with 8 g of a mixture for fusion in the muffle at a temperature of 950 °C. the Melt is dissolved by adding 15−30 cmof hydrochloric acid diluted 1:1, and 40−50 cm
of water, heated to dissolve water, transferred to a volumetric flask with a capacity of 250 cm
, cooled, adjusted to the mark with water and mix.
From thus prepared solution determine the mass fraction of aluminum, iron, calcium, and titanium, selecting for each definition corresponding aliquot part.
Of volumetric flasks with a capacity of 250 cmtaken 100 cm
of solution in a volumetric flask with a capacity of 250 cm
, adding 25 cm
of the solution Trilon B, is heated nearly to boiling, add with stirring 50 cm
of sodium hydroxide solution, cooled, adjusted to the mark with water and mix. The solution is filtered through a dry folded filter of «blue ribbon». The filtrate collected in a dry conical flask. The first portion of the filtrate discarded.
Take 100−200 cmof solution was placed in a conical flask with a capacity of 500 cm
, add 3−4 drops of orange kylinalove and neutralize the solution with hydrochloric acid diluted 1:1 until the color of indicator yellow. After neutralization to the solution add 20 cm
acetate buffer solution, boiled for 2−3 min, cooled, again add 3−4 drops of orange and kylinalove octarepeat excess Trilon B solution of nitrate of zinc to change the color of the solution from yellow to pink.
At the same time through all stages of the analysis carried out control experience for contamination of reagents.
(Changed edition, Rev. N 3).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of aluminium () in percent is calculated by the formula
where — volume of solution Trilon B with molar concentration of 0.05 mol/DM
contained in aliquotes part taken for the titration, cm
;
— correction factor of the solution Trilon B with molar concentration of 0.05 mol/DM
;
— the volume of zinc nitrate solution with molar concentration of 0.05 mol/DM
consumed for titration of the excess Trilon B, cm
;
0,00135 — mass concentration of the solution Trilon B with molar concentration of 0.05 mol/DM, expressed in grams of aluminum per cm
;
— the total volume of solution, cm
;
— volume of the volumetric flask, which produce a separation of iron and titanium, cm
;
— aliquotes volume of the solution taken for the separation of iron and titanium, cm
;
— aliquotes volume of the solution taken for the determination of aluminium, cm
;
— the weight of the portion of the silicon,
If for the reference experiment add the same number of solution Trilon B as for sample, mass fraction of aluminium () in percent is calculated by the formula
where — the volume of zinc nitrate solution with molar concentration of 0.05 mol/DM
consumed for titration of the excess Trilon B in a control experiment, cm
;
— the volume of zinc nitrate solution with molar concentration of 0.05 mol/DM
consumed for titration of the excess Trilon B in the sample, cm
;
— the total volume of solution, cm
;
— volume of the volumetric flask, which produce a separation of iron and titanium, cm
;
— aliquotes volume of the solution taken for the separation of iron and titanium, cm
;
— aliquotes volume of the solution taken for the determination of aluminium, cm
;
— the weight of the portion of the silicon,
4.2. Permissible discrepancies in the results of parallel definitions should not exceed the values given in the table.
| Mass fraction of aluminum, % | The allowable divergence convergence % |
Permissible differences of reproducibility, % | |||||
| From |
0,30 | to | Of 1.00 | incl. |
0,03 | 0,05 | |
| SV. |
Of 1.00 | « | 1,60 | « | 0,06 | 0,09 | |
The method used in the dispute in the assessment of the quality of the silicon crystal.
Section 4. (Changed edition, Rev. N 3).
5. ATOMIC ABSORPTION METHOD
The essence of the method consists in measuring the atomic absorption of aluminum at a wavelength of 309,3 nm in a flame nitrous oxide — acetylene.
Section 5. (Added, Rev. N 3).
6. APPARATUS, REAGENTS AND SOLUTIONS
Atomic absorption spectrometer with all accessories of the «Perkin-Elmer», «Saturn» or similar.
Lamp with hollow cathode for aluminium.
Acetylene in cylinders for technical GOST 5457−75.
Nitrous oxide cylinders medical.
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Nitric acid GOST 4461−77.
Hydrofluoric acid according to GOST 10484−78.
Sulfuric acid GOST 4204−77, diluted 1:1.
Sodium carbonate according to GOST 83−79.
Sodium tetraborate 10-water according to GOST 4199−76, dehydrated at 400 °C.
Mix for fusion: mix sodium carbonate and sodium tetraborate in a ratio of 6:1 (by weight).
Aluminum brand A995 according to GOST 11069−74*.
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* On the territory of the Russian Federation GOST 11069−2001. — Note the manufacturer’s database.
A standard solution of aluminum: 0,5000 g of aluminum is placed in a beaker with a capacity of 400 cm, in small portions add 50 cm
of hydrochloric acid diluted 1:1. The solution was heated until complete dissolution of aluminium. After cooling, the solution is transferred to a volumetric flask with a capacity of 500 cm
, made up to the mark with water and mix.
1.0 cmof the solution contains 0.001 g of aluminium.
The solution-background: 160 g of a mixture for fusion were placed in a glass with a capacity of 1000 cm, moistened with water and gently, in small portions, pour the 700 cm
of hydrochloric acid diluted 1:1.
After dissolution the solution was transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.
Section 6. (Added, Rev. N 3).
7. ANALYSIS
7.1. A portion of the silicon mass of 2 g is placed in a platinum Cup, moisten with water, add 30 cmhydrofluoric acid, and then small portions of 15 cm
of nitric acid.
Careful rotation stirred the contents of the Cup. At the end of the violent reaction of the walls of the Cup and rinse with water, add 5 cmof sulphuric acid diluted 1:1, and evaporated in the bath until the white fumes of sulfuric acid. Then cooled, carefully washed the walls of the Cup with water and evaporated to dryness on the bath.
To the dry residue add 8 g of a mixture for fusion and fused in a muffle at a temperature of 950 °C. the Melt is dissolved by adding 30 cmof hydrochloric acid diluted 1:1, and 40−50 cm
of water, heated until complete dissolution of water, transferred to a volumetric flask with a capacity of 250 cm
, cooled, adjusted to the mark with water and mix.
In the prepared solution determine the mass percent of aluminum, calcium, iron and titanium. At the same time through all stages of the analysis spend control experience.
Obtained from the sample solution, the solution control experience and solutions to build a calibration chart, measure the value of atomic absorption of aluminum at a wavelength of 309,3 nm in a flame nitrous oxide — acetylene.
A lot of aluminium in sample solution and in the solution of control and experience determined by the calibration schedule, which is built with every shot.
7.2. Construction of calibration curve
In six volumetric flasks with a capacity of 250 cmpour 50 cm
of the solution-background. Then enter 0; 2,0; 5,0; 10,0; 20,0; 30,0 cm
standard solution, which corresponds to 0; 0,002; 0,005; 0,010; 0,020; 0,030 g of aluminum. The solutions were topped up to the mark with water, mix and measure the absorbance of solutions as specified in clause 7.1.
According to the obtained values of atomic absorption and corresponding masses of aluminium to build the calibration graph.
Section 7. (Added, Rev. N 3).
8. PROCESSING OF THE RESULTS
8.1. Mass fraction of aluminium () in percent is calculated by the formula
where is the mass of aluminium in the sample solution found by the calibration schedule g;
— the mass of the aluminium in solution in the reference experiment, was found in the calibration schedule g;
— the weight of the portion of the sample,
8.2. Permissible discrepancies in the results of parallel definitions should not exceed the values given in the table.
Section 8. (Added, Rev. N 3).
