GOST 20997.4-81
THALLIUM
METHOD CHEMICAL-SPECTRAL DETERMINATION
ALUMINUM, IRON, BISMUTH, CADMIUM, INDIUM, COPPER,
MANGANESE, NICKEL, LEAD, SILVER AND ZINC
IPK PUBLISHING HOUSE OF STANDARDS
Moscow
INTERSTATE STANDARD
THALLIUMMethod chemical-spectral determination of aluminium, Thallium. Method of chemical and spectral determination |
GOST Instead |
*Publishing (January 2001 g.) with Changes No. 1, 2, approved in November 1986, g., April 1992 g. (ICS 2-87, 7-92)
The decision of the State Committee USSR on standards on 25 may 1981 No. 2589 the introduction of set
with 01.07.82
Resolution of the state standard from
This standard specifies the chemical-spectral method for the determination of aluminium, iron, bismuth, cadmium, indium, copper, manganese, Nickel, lead, silver and zinc in thallium mass fraction in percentage:
aluminum from 1 ∙ 10-5 to 5 ∙ 10-4
iron 8 ∙ 10-6 to 5 ∙ 10-4
of bismuth of 3 ∙ 10-6 to 1 ∙ 10-4
cadmium from 2 ∙ 10-6 to 1 ∙ 10-4
India of 3 ∙ 10-6 to 1 ∙ 10-4
copper from 2 ∙ 10-6 to 1 ∙ 10-4
manganese 1 ∙ 10-5 to 1 ∙ 10-4
Nickel of 3 ∙ 10-6 to 1 ∙ 10-4
lead 8 ∙ 10-6 to 1 ∙ 10-4
silver 1 ∙ 10-6 to 1 ∙ 10-4
zinc 7 ∙ 10-6 to 1 ∙ 10-4
The method is based on preliminary chemical concentration of impurities, the separation of the main quantity of thallium extraction ββ'-dichlorethylene with ether (hloreksa) in the form of bromide of 1 N. the solution bromatological acid. The solution containing the impurities, is evaporated on the graphite collector, consisting of a graphite powder with the addition of 4% sodium chloride in the case of determining the mass fraction of aluminum, bismuth, iron, cadmium, indium, copper, manganese, Nickel, lead, silver and 0.1% of sodium chloride in the case of determining the mass fraction of zinc.
Spectral analysis of the obtained concentrate of impurities is carried out by the method of «three standards» with the evaporation of samples from the crater of the carbon electrode in the arc of a DC power of 15 A.
(Changed edition, Rev. No. 1).
1. GENERAL REQUIREMENTS
General requirements for method of analysis according to GOST 20997.0−81.
2. APPARATUS, REAGENTS AND MATERIALS
The quartz spectrograph medium dispersion of any type, allowing to obtain a range of up to 220,0 400,0 nm, being equipped with an illumination system of the slit and the three-step attenuator.
The diffraction type spectrograph DFS-8 (first order), being equipped with an illumination system of the slit (grating 600 gr./mm).
A constant current source 250 — 300 30 — 50 A.
The arc generator is adapted to ignite the DC arc high frequency discharge.
Microphotometer of any type, allowing to measure the density of the blackening of analytical lines.
Spectromancer of PS-18.
Libra torsion bar type W or similar with a weighing error of no more than 0.001 g.
Analytical scale with a weighing error of no more than 0,0002 g.
The infrared lamp with a laboratory-type autotransformer RNO-250−2.
Boxes of organic glass or similar.
Mortar made of organic glass with a pestle.
Quartz ware (cups, glasses, crucibles, separating funnels).
Carbon electrodes high purity with a diameter of 6 mm with the size of the crater 4x3 and 4x4 mm.
Contractrate coal high purity 6 mm in diameter, sharpened to a truncated cone with ground diameter of 2 mm.
The graphite powder of high purity according to GOST 23462−95.
Distilled water GOST 6709−72 distilled in a quartz apparatus or purified on a column of ionization.
ββ'-dichloromethylene ether (hloreksa), purified in the following way. In a separating funnel with a capacity of 1000 cm3 the hloreksa (700 — 800 cm3) was washed with three times 100 cm3 of solution with a molar concentration of 3 mol/DM3 hydrochloric acid and twice with 130 cm3 of water. Shake the hloreksa with a solution of acid and water within 5 min. After separation of the liquids (20 — 30 min) water of the cast. For a more complete delamination after the last wash, the liquid left in the funnel overnight. The washed hloreksa distilled twice in a quartz apparatus (collecting the fraction boiling at 175 — 178 °C). Use glycerin bath, covered with a layer of paraffin.
Hydrochloric acid by the GOST 3118−77, solution with a molar concentration of 3 mol/DM3.
Glycerin according to GOST 6259−75.
Paraffin according to GOST 23683−89.
Nitric acid GOST 4461−77, double-distilled in quartz apparatus, or nitric acid of high purity according to GOST 11125−84.
Bromatologia acid according to GOST 2062−77, double-distilled, solutions with molar concentration of 1 and 8 mol/DM3. The concentration bromatological acid set by titration with sodium hydroxide solution.
Bromine according to GOST 4109−79, distilled in a quartz apparatus in a water bath at a water temperature of (60 ± 5) °C. Collect the bromine under water in a quartz cone.
Sodium hydroxide according to GOST 4328−77.
Sodium chloride brand OS.h.
The technical rectified ethyl alcohol GOST 18300−87.
Photographic plates «spectrographic» types II, I (or slide).
Bismuth GOST 10928−90.
Cadmium GOST 1467−93.
Indium GOST 10297−94.
Manganese GOST 6008−90.
Copper GOST 859−78.
Nickel GOST 849−97.
Silver GOST 6836−80.
Aluminium metal according to GOST 11069−74.
Carbonyl iron radio — GOST 13610−79.
Lead according to GOST 3778−98.
Zinc GOST 3640−94.
Solutions of nitric or hydrochloric acid, containing 2 mg of bismuth, cadmium, indium, manganese, copper, Nickel, silver and 10 mg of aluminium, iron, lead and zinc in 1 cm3. For the preparation of solutions used metals with a mass fraction of main substance not less than 99.99%.
Preparation of solutions is given in Appendix GOST 20997.2−81.
Samples comparison.
Note. Allowed the use of devices with photoelectric registration of spectrum and other spectrographic equipment and facilities other materials and reagents subject to receipt of the accuracy characteristics as specified in this standard.
Section 2. (Changed edition, Rev. No. 1, 2).
3. PREPARATION FOR ASSAY
The basis for the preparation of samples of comparison is graphite powder of high purity with the addition of 4% sodium chloride (in the determination of the mass fraction of zinc in a graphite powder was added 0.1% of sodium chloride). The purity of the prepared bases check spectrographically under the conditions of analysis are described in sect. 4. For the preparation of a primary sample with a mass fraction of bismuth, cadmium, indium, manganese, copper, Nickel, silver, 0.02% each of aluminum, iron, lead and zinc at 0.1% each in 5 g bases add 0.5 cm3 of the standard solutions of impurity elements. With the introduction of the solutions ensure that the solution, impregnating a basis, did not reach the sides and bottom of the Cup. Therefore, as fluids of impurities, basis dried under a lamp. After the introduction of all solutions of the resulting sample is thoroughly dried and mixed in a mortar made of organic glass for 30 — 40 min. Then by the method of serial dilutions of the brain and of each newly prepared sample basis receive a series of working samples comparison with a mass fraction of bismuth, cadmium, indium, manganese, copper, Nickel, silver: 2 ∙ 10-5; 6 ∙ 10-5; 2 ∙ 10-4; 6 ∙ 10-4; 2 ∙ 10-3 % and with a mass fraction of aluminum, iron, lead and zinc: 1 ∙ 10-4; 3 ∙ 10-4; 1 ∙ 10-3; 3 ∙ 10-3; 1 ∙ 10-2 %. References prepared according to the specified method must be certified in accordance with the regulatory documents approved in the prescribed manner. Keep the samples and based in buksh or jars with screw caps. Shelf life 1 year
Section 3. (Changed edition, Rev. No. 2).
4. ANALYSIS
4.1. The chemical concentration of impurities. A portion of the thallium weighing 1,000 — 1,500 g was placed in a quartz Cup with a capacity of 30 — 50 cm3, dissolved in 4 — 6 cm3 respectively nitric acid and evaporated under an infrared lamp at a temperature of about 90 °C to obtain the wet salts. Then double-handle 2 — 3 cm3 solution of methyl-hydrogen acid with molar concentration of 8 mol/DM3 with the addition of 4 — 5 drops of bromine and evaporated to obtain a wet salts. The contents of the Cup 8 is dissolved in 10 cm3 of 1 n solution of methyl-hydrogen acid, adding 5 — 6 drops of bromine to dissolve the precipitate, and transfer the solution into a quartz separating funnel. The Cup is washed with 2 cm3 of the same acid. Add in a funnel of 10 — 12 cm3 hloreksa (the ratio of aqueous and organic phases 1:1) and smooth swinging funnel extracted for 3 min. After separation the organic phase is poured in the separating funnel add 1 — 2 drops of bromine, 10 — 12 cm3 hloreksa and repeat the extraction two more times. The aqueous phase, after separation of the organic, through the throat poured into a quartz Cup with a capacity of 30 cm3, evaporated to half volume under a heat lamp, add 50 mg of a graphite powder containing 4% of sodium chloride, and evaporated to dryness at a temperature of about 90 °With (when determining the zinc concentration of impurities is evaporated on 100 mg of a graphite powder containing 0.1% of sodium chloride). Wash the dry residue from the walls of the Cup a small amount of water (1.5 — 2.0 cm3) and again evaporated to dryness at a temperature of about 90 °C. the Dry residue is passed for spectral analysis. Enrichment of lead from the four parallel batches. Simultaneously with the preparation of samples through all stages of analysis performed four control experience with all reagents.
(Changed edition, Rev. No. 1, 2).
4.2. Spectral analysis of the concentrate of impurities
4.2.1. Conditions of spectrographically in the determination of aluminium, bismuth, iron, cadmium, indium, copper, manganese, Nickel, lead and silver
The prepared suspension concentrates and comparison samples weighing 20 mg was placed in a crater electrode (anode) with a depth of 3 mm and a diameter of 4 mm. the Electrodes are pre-fired in an arc DC power is 10 A for 10 s. Spectra of samples comparisons and control experience photographed with the aid of quartz or diffraction spectrograph with being an illumination system of the slit in the arc of a DC power of 15 A. the exposure Time of 20 s. the Width of the slit of a spectrograph 0,015 mm. in Front of the slit establish a three-tier reliever.
In the cassette two charged plates: for the spectral range from 200,0 310,0 to nm — type II, for spectral range from to 310,0 400,0 nm — type I or slide.
4.2.2. Conditions of spectrographically when determining zinc
The prepared suspension concentrates and comparison samples weighing 45 mg was placed in the crater of a carbon electrode (anode) depth and diameter of 4 mm. the Electrodes are pre-fired in an arc DC power is 10 A for 10 s. Spectra of samples comparisons and control experience photographed by using the diffraction type spectrograph DFS-8 with three-lens Achromat illumination system of the slit in the arc of a DC power of 15 A. the exposure Time 8 — 10 s. the Width of the slit of a spectrograph 0,020 mm.
The spectra of each of the obtained concentrate is photographed twice, sample comparison — three times on the same photographic plate.
4.2.1,
5. PROCESSING OF THE RESULTS
5.1. On spectrograms using microphotometry measure of the blackening of the lines defined elements and the surrounding background. The calibration graphs are built in coordinates ΔS — lgC, where ΔS = Sl+f — Sf, With the mass fraction of the element in the calibration samples in %.
Mass fraction of impurity in the thallium (X) in percent is calculated by the formula
where m is the mass of the concentrate, mg;
C — the average mass fraction of impurities in the concentrate analyzed samples was found in the calibration schedule, %;
C1 — average mass fraction of impurities in the concentrate a control of the experience, found by calibration schedule, %;
m1 — weight of sample, mg.
Photometric the following analytical lines (wavelengths in nm):
aluminium — Al I 308,21;
bismuth — Bi I 306,77;
iron — Fe I 302,06;
cadmium — Cd I 228,80;
indium — In I 325,61;
copper — Cu I 327,40;
manganese — Mn I 257,61;
Nickel — Ni I 300,24;
lead — Pb I 283,31;
silver — Ag I 328,07;
zinc — Zn I 334,50.
5.2. Discrepancies in the results of four parallel samples (d), as well as discrepancies in the results of the two analyses (D) shall not exceed the values given in the table (R = 0,95).
| The name of the element | Mass fraction of element, % | The divergence of the four results of the parallel definitions % | The discrepancy between the results of two tests, % |
| Aluminium | 1 ∙ 10-5 | 5 ∙ 10-6 | 5 ∙ 10-6 |
| 2 ∙ 10-5 | 1 ∙ 10-5 | 1 ∙ 10-5 | |
| 4 ∙ 10-5 | 2 ∙ 10-5 | 2 ∙ 10-5 | |
| 8 ∙ 10-5 | 3 ∙ 10-5 | 4 ∙ 10-5 | |
| 1 ∙ 10-4 | 4 ∙ 10-5 | 5 ∙ 10-5 | |
| 2 ∙ 10-4 | 7 ∙ 10-5 | 9 ∙ 10-5 | |
| 5 ∙ 10-4 | 2 ∙ 10-4 | 2 ∙ 10-4 | |
| Bismuth, indium, Nickel | 3 ∙ 10-6 | 1,5 ∙ 10-6 | 2 ∙ 10-6 |
| 6 ∙ 10-6 | 3 ∙ 10-6 | 4 ∙ 10-6 | |
| 1 ∙ 10-5 | 5 ∙ 10-6 | 6 ∙ 10-6 | |
| 2 ∙ 10-5 | 7 ∙ 10-6 | 9 ∙ 10-6 | |
| Bismuth, Nickel, indium | 4 ∙ 10-5 | 1,5 ∙ 10-5 | 2 ∙ 10-5 |
| 8 ∙ 10-5 | 3 ∙ 10-5 | 3 ∙ 10-5 | |
| 1 ∙ 10-4 | 4 ∙ 10-5 | 5 ∙ 10-5 | |
| Iron, lead | 8 ∙ 10-6 | 4 ∙ 10-6 | 5 ∙ 10-6 |
| 1 ∙ 10-5 | 5 ∙ 10-6 | 6 ∙ 10-6 | |
| 2 ∙ 10-5 | 1 ∙ 10-5 | 1 ∙ 10-5 | |
| 4 ∙ 10-5 | 2 ∙ 10-5 | 2 ∙ 10-5 | |
| 8 ∙ 10-5 | 3 ∙ 10-5 | 4 ∙ 10-5 | |
| 1 ∙ 10-4 | 4 ∙ 10-5 | 5 ∙ 10-5 | |
| 2 ∙ 10-4 | 7 x 10-5 | 9 ∙ 10-5 | |
| 5 ∙ 10-4 | 2 x 10-4 | 2 ∙ 10-4 | |
| Cadmium, copper | 2 ∙ 10-6 | 1 ∙ 10-6 | 1 ∙ 10-6 |
| 4 ∙ 10-6 | 2 ∙ 10-6 | 2 ∙ 10-6 | |
| 8 ∙ 10-6 | 3 ∙ 10-6 | 4 ∙ 10-6 | |
| 1 ∙ 10-5 | 5 ∙ 10-6 | 5 ∙ 10-6 | |
| 2 ∙ 10-5 | 1 ∙ 10-5 | 1 ∙ 10-5 | |
| 4 ∙ 10-5 | 2 ∙ 10-5 | 2 ∙ 10-5 | |
| 8 ∙ 10-5 | 3 ∙ 10-5 | 4 ∙ 10-5 | |
| 1 ∙ 10-4 | 4 ∙ 10-5 | 5 ∙ 10-5 | |
| Manganese | 1 ∙ 10-5 | 4 ∙ 10-6 | 5 ∙ 10-6 |
| 2 ∙ 10-5 | 8 ∙ 10-6 | 1 ∙ 10-5 | |
| 4 ∙ 10-5 | 2 ∙ 10-5 | 2 ∙ 10-5 | |
| 8 ∙ 10-5 | 3 ∙ 10-5 | 4 ∙ 10-5 | |
| 1 ∙ 10-4 | 4 ∙ 10-5 | 5 ∙ 10-5 | |
| Silver | 1 ∙ 10-6 | 5 ∙ 10-7 | 7 ∙ 10-7 |
| 2 ∙ 10-6 | 1 ∙ 10-6 | 1,5 ∙ 10-6 | |
| 4 ∙ 10-6 | 2 ∙ 10-b | 2 ∙ 10-6 | |
| 8 ∙ 10-6 | 3 ∙ 10-6 | 4 ∙ 10-6 | |
| 1 ∙ 10-5 | 5 ∙ 10-6 | 5 ∙ 10-6 | |
| 2 ∙ 10-5 | 1 ∙ 10-5 | 1 ∙ 10-5 | |
| 4 ∙ 10-5 | 2 ∙ 10-5 | 2 ∙ 10-5 | |
| 8 ∙ 10-5 | 3 ∙ 10-5 | 4 ∙ 10-5 | |
| 1 ∙ 10-4 | 4 ∙ 10-5 | 5 ∙ 10-5 | |
| Zinc | 7 ∙ 10-6 | 3 ∙ 10-6 | 4 ∙ 10-6 |
| 1 ∙ 10-5 | 5 ∙ 10-6 | 5 ∙ 10-6 | |
| 2 ∙ 10-5 | 1 ∙ 10-5 | 1 ∙ 10-5 | |
| 4 ∙ 10-5 | 2 ∙ 10-5 | 2 ∙ 10-5 | |
| 8 ∙ 10-5 | 3 ∙ 10-5 | 4 ∙ 10-5 | |
| 1 ∙ 10-4 | 4 ∙ 10-5 | 5 ∙ 10-5 |
Permitted discrepancies for the intermediate mass fraction calculated using linear interpolation.
5.1, 5.2. (Changed edition, Rev. No. 2).
