GOST 23862.18-79
GOST 23862.18−79 Neodymium, gadolinium and their oxides. Method of determination of impurities of oxides of rare earth elements (with Change No. 1)
GOST 23862.18−79
Group B59
INTERSTATE STANDARD
NEODYMIUM, GADOLINIUM AND THEIR OXIDES
Method of determination of impurities of oxides of rare earth elements
Neodymium, gadolinium and their oxides. Method of determination of rare-earth element oxides
ISS 77.120.99
AXTU 1709
Date of introduction 1981−01−01
The decision of the State Committee USSR on standards on October 19, 1979 N 3989 date of introduction is established 01.01.81
Limitation of actions taken by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (ICS 11−95)
EDITION with Change No. 1, approved in April 1985 (IUS 7−85).
This standard specifies the chemical activation method for the determination of impurities of oxides of rare earth elements neodymium, gadolinium and their oxides.
The method is based on irradiation of the analyte samples and comparison with thermal neutron flux (1−3)·10on natural hair./cm·s with subsequent measurement of activity of radioactive isotopes of elements of impurities in the samples of comparison and in the fractions isolated from irradiated materials analyzed by the method of extraction chromatography.
Intervals determined by a mass fraction of impurities of oxides:
in the neodymium and its oxide: | |
Lantana | from 5·10% to 2·10% |
praseodymium | from 5·10% 1·10% |
Samaria | 2·10% to 2·10% |
europium | from 5·10% to 5·10% |
in gadolinium and its oxide: | |
europium | from 5·10% 1·10% |
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 23862.0−79.
2. APPARATUS, MATERIALS AND REAGENTS
The research reactor of the pressurized water type TVR with a stream of neutrons (1−3)·10on natural hair./cm·s and the ratio of thermal neutrons to fast not less than 20:1.
Gamma-ray spectrometer with a semiconductor, consisting of a multichannel analyzer, amplification of signals, a semiconductor germanium-lithium detector with photoaffinity gamma line of cesium-137 is not less than 0,8−1,0% (volume of the detector not less than 20−30 cm). The resolution of the spectrometer in the gamma line of cesium-137 (0,682 MeV) to (3−4) Kev.
Packaging material for the analyzed samples comparison: quartz boxy volume of 0.5 cmwith a glass stopper, aluminum foil 995 And thickness of 0.2−0.3 mm.
The aluminum canisters are made of aluminum brand 995-A.
Container lead transport brand TC-150 or TC-80.
The container table of the brand CT.
Personal protective equipment against radiation and contamination by radionuclides according to the requirements of OSP-72*.
_______________
* Act SP 2.6.1.799−99, here and hereafter. — Note the manufacturer’s database.
Screen protective from lead bricks and lead glass.
Gamma-spectrometric sources exemplary (OSGI) according to GOST 8.315−97.
Radiometer «TISS» or similar.
Chromatographic glass column with a height of 600 mm with a water jacket. Diagram of speakers according to GOST 23862.7−79; N 1 column — internal diameter 16 mm, column N 2 — inner diameter 14 mm.
Vaporizer glass. Diagram of the evaporator according to GOST 23862.7−79.
The thermostat TS-16 or similar, which provides hot water to (40±2) °C.
Libra special microanalytical SMD-1000.
Potentiometer LPU-01, or similar, for measuring pH from 1 to 11.
Ball mill metal with a diameter of 210 mm, height 200 mm, weight 4 kg.
Metal balls with a diameter of 30 mm, 25 PCs.
Sieves of metal.
Drying oven with thermostat providing temperatures up to 200 °C.
Motor sewing DSS-2.
Bath water.
Tile electric.
Reducers oxygen.
Pressure gauges according to GOST 2405−88 1−4 kgf/cm.
Water jet pump laboratory glass according to GOST 25336−82.
Glasses glass.
Separating funnel with a capacity of 1000, 2000 cm.
A Buchner funnel with a diameter of 132 mm.
Flasks Bunsen.
Pipette.
Burettes with a capacity of 25 cm.
Boxy glass with a capacity of 18 cm, type SV 24/10.
The glass capillaries with a length of 150 mm with a diameter delay of 1−1. 5 mm.
Glass cylinders with a capacity of 1,000 cmwith a glass stopper.
The measuring cylinders.
Flasks glass conical.
A glass bulb with a capacity of 1,000 cmwith a reflux condenser.
Volumetric flasks.
Glass propeller stirrer.
A device for distillation flask with a capacity of 500, 1000 cm.
Porcelain Cup with a diameter of 210 mm.
Tube rubber.
The polyethylene film.
Paper universal indicator.
Silica gel KSK N 2 or N 2.5.
Oxide of lanthanum, praseodymium, samarium, europium purity not less than 99.999%.
Copper sulfate 5-water according to GOST 4165−78, 0.5 mol/DMsolution.
Standard solutions of lanthanum, samarium, europium concentration 1 µg/cm, calculated on oxide: 0.01 g of each REE oxide with a purity not less than 99.999% is dissolved in 3 cmof concentrated hydrochloric acid, evaporated to wet salts, which are dissolved in 5 cm1 mol/DMof hydrochloric acid. The solutions were transferred to volumetric flasks with a capacity of 100 cmand adjusted to the mark of 1 mol/DMhydrochloric acid. At 1 cmof each solution is transferred to volumetric flasks with a capacity of 100 cmand adjusted to the mark of 1 mol/DMhydrochloric acid.
Standard solution praseodymium concentration of 100 µg/cm, calculated on oxide: 0.01 g of praseodymium oxide with purity not less than 99.999% is dissolved in 3 cmof concentrated hydrochloric acid is evaporated to wet salts, which are dissolved in 5 cm1 mol/DMhydrochloric acid, the solution transferred to a volumetric flask with a capacity of 100 cmand adjusted to the mark of 1 mol/DMhydrochloric acid.
Sodium acetate according to GOST 199−78, H. h, a saturated solution.
Sodium carbonate crystal according to GOST 84−76, H. h, solution with a concentration of 50 g/DM.
Sodium chloride according to GOST 4233−77, a solution with a concentration of 100 g/DM.
Sodium hydroxide according to GOST 4328−77, H. h
The gaseous nitrogen according to GOST 9293−74 or argon gas GOST 10157−79.
Arsenazo III solution with a concentration of 0.2 g/DM.
Hydrochloric acid according to GOST 14261−77, H. h. or h. d. a., concentrated, 0,1; 0,3; 0,5; 0,8; 1,2; 7 mol/DMtitrated solutions.
Nitric acid GOST 4461−77, H. h. concentrated.
Ammonia water according to GOST 3760−79, H. h, concentrated solution with a concentration of 50 g/DM.
Hydrogen peroxide according to GOST 10929−76.
Di (2-ethylhexyl) phosphoric acid (D2EHPA), technical (50−70%) or improved (95%).
D2EHPA 100% get technical D2EHPA (sec. 3 GOST 23862.7−79 or improved D2EHPA (sec. 3 GOST 23862.7−79).
The ethyl ether.
The technical rectified ethyl alcohol GOST 18300−87.
The dimethyldichlorosilane.
Carbon tetrachloride according to GOST 20288−74.
The dimethyldichlorosilane solution in carbon tetrachloride (1:4).
Acetone according to GOST 2603−79.
The ethylene glycol according to GOST 10164−75.
Ascorbic acid, a solution with a concentration of 5 g/DM1 mol/DMhydrochloric acid; prepared on the day of use.
Sec. 2. (Changed edition, Rev. N 1).
3. PREPARATION FOR ASSAY
3.1. Purification of D2EHPA (technical or superior), preparation of silica gel, preparation of the adsorbent, filling column, ready to work, machinery work on the extraction-chromatographic column according to sect.3 23862.7 GOST-79.
4. ANALYSIS
4.1. Analysis of neodymium oxide or its
Determination of oxides of lanthanum, praseodymium, samarium and europium
Concentrate impurities get in an extraction-chromatographic column No. 1. Column filled with sorbent (25 g of silica gel with a grain size of 0.06−0.07 mm+15 cm100% D2EHPA, the free volume of the sorbent 40 cm).
A portion of metal neodymium by weight of 0.022 g or 0.025 g of its oxide was placed in a quartz buxo, pre-boiled in concentrated hydrochloric acid, washed with distilled water, alcohol, ether and dried. Buxu lid and packaged in aluminum foil. Strips obessilennaya filter («blue ribbon») size 5x15 mm nakatyvaet 0.1 cmstandard solutions of lanthanum, praseodymium, samarium and europium (each solution nakatyvaet on a separate strip); after nakapyvaniya every drop strip is dried over the hot plate. The dried strips are coated standard solutions (comparison samples) wrapped separately in aluminum foil.
The sample and the comparison sample (OS) tag, is placed in a single aluminum case (small block), rinsed with acetone or ethyl alcohol and irradiated in a nuclear reactor for 20 hours with a neutron flux of 1.2·10on natural hair./cm·C. the Transportation of irradiated samples and specimens comparison is carried out in a lead transport container of the type TC (TC-80, TC-150) on a special machine.
Quartz buxo the irradiated sample is placed behind a protective shield of lead bricks and lead glass. Forceps remove aluminum foil, open the lid and the irradiated sample is dissolved in hot 7 mol/DMhydrochloric acid. The solution was transferred to a capillary glass with a capacity of 50 cm. Buxu washed with hot 7 mol/DMhydrochloric acid 3 or 4 times. Rinse solutions are transferred with a capillary into the same beaker. The solution is evaporated almost to dryness; the REE chlorides are dissolved in 2 cmof 0.1 mol/DMhydrochloric acid and passed through an extraction-chromatographic column No. 1, which has been previously washed with 0.1 m hydrochloric acid. Engineering work on the column sec. 3 23862.7 GOST-79.
The beaker containing the sample solution, washed with 5 cmof 0.1 mol/DMhydrochloric acid. Flushing solution passed through the column. The first 40 cmof the eluate (including the volume of sample and wash solution) is collected in the measuring cylinder capacity of 50 cm, then the eluate is collected into jars with a capacity of 18 cmin portions of 5 cmand determine the presence of sodium-24 in every portion of the radioactivity measurement solution for semiconductor gamma-spectrometer for 1−5 min (see p.4.3). The absence in the controlled portions of sodium-24 in the measurement within 5 min indicates complete elution from the column.
After complete elution of sodium-24 is passed through a column of 0.3 mol/DMhydrochloric acid and 70 cm collectthe eluate in a measuring cylinder with a capacity of 100 cm(the main fraction of lanthanum). The eluate is collected into jars with a capacity of 18 cmin portions of 5 cmand determine the presence of lanthanum-140 in every portion of the radioactivity measurements of a solution for the gamma-spectrometer for 1−5 minutes in the Absence of a controlled portion of the lanthanum-140 in the measurement within 5 min indicates complete elution from the column. The portions of eluate containing lanthanum-140, is added to the main fraction of lanthanum-140 (graduated cylinder), is evaporated in a glass evaporator to a volume of 10−15 cm, carried over to buxu, with a capacity of 18 cmand is evaporated to a volume of 1 cm(fraction of lanthanum).
After complete elution of Lantana passed through a column of 0.5 mol/DMhydrochloric acid and 70 cm collectthe eluate in a measuring cylinder with a capacity of 100 cm(the main fraction of praseodymium and neodymium). Next, the eluate is collected into jars with a capacity of 18 cmin portions of 5 cm, in each of which determine the presence of neodymium-147 and promethium-147 measurement of radioactivity of the solution on the gamma spectrometer for 1−5 minutes Monitoring is carried out at photopic (91 Kev). Secondary increase in the height of this fotopic proves that the controlled portions of promethium. The portions of eluate not containing promethium, is added to the main fraction of praseodymium and neodymium in a measuring cylinder, is evaporated in the evaporator to a volume of 10−15 cm, carried over to buxu with a capacity of 18 cmand is evaporated to a volume of 1 cm(fraction of praseodymium-neodymium).
After appearing in the eluate PM the next 150 cmeluate collected in a beaker with a capacity of 200 cm. Next, the eluate is collected into jars with a capacity of 18 cmin portions of 5 cm, in each of which detect the presence of promethium in the measurement of radioactivity of the solution on the gamma spectrometer for 1−5 minutes Servings containing promethium unite with the main portion of promethium and removed as radioactive waste in accordance with the rules OSP-72.
After complete elution of promethium through a column flow of 0.8 mol/DMhydrochloric acid and 70 cm collectthe eluate in a measuring cylinder with a capacity of 100 cm(the main fraction of samarium-153). Next, the eluate is collected into jars with a capacity of 18 cmin portions of 5 cm, in each of which define the presence of samarium-153 radioactivity measurements of a solution for the gamma-spectrometry within 1−5 min. Portions of eluate containing samarium-153, is added to the main fraction of samarium-153 (graduated cylinder), is evaporated in the evaporator to a volume of 10−15 cm, carried over to buxu with a capacity of 18 cmand is evaporated to a volume of 1 cm(fraction of Samaria).
Next, using a column flow of 1.2 mol/DMhydrochloric acid and 70 cm collectthe eluate in a measuring cylinder with a capacity of 100 cm(the main fraction of europium). Then the eluate is collected into jars with a capacity of 18 cmin portions of 5 cm, in each of which detects the presence of europium-152 and 152measurement of radioactivity of the solution on the gamma spectrometer for 1−5 min. Portions of eluate containing the europium-152 and 152, is added to the main fraction of europium in a measuring cylinder, is evaporated in the evaporator to a volume of 10−15 cm, carried over to buxu with a capacity of 18 cmand is evaporated to a volume of 1 cm(fraction of europium).
After complete elution of europium is passed through a column of 300 cm7 mol/DMof hydrochloric acid and 50 cmof 0.1 mol/DMhydrochloric acid. The eluates are removed as radioactive waste.
Irradiated samples compare free from aluminum foil behind the protective shield of lead bricks and lead glass, put each into a separate glass buxu with a capacity of 18 cm, pour 0.5 cmof hot concentrated nitric acid and after the destruction of the paper added to 0.5 cmof distilled water.
Fraction of lanthanum, of praseodymium-neodymium, samarium, europium and comparison samples measured on the semiconductor gamma spectrometer (
see p.4.3).
4.2. Analysis of gadolinium or of its oxides
Determination of europium
The fraction of europium get in an extraction-chromatographic column N 2. Column filled with sorbent (12.5 g of silica gel with a grain size of 0.06−0.07 mm+7.5 cm100% D2EHPA, the free volume of the sorbent 20 cm).
A portion of the metal gadolinium mass 0,0009 g or 0.001 g of its oxide is weighed on a special microanalytical scales, placed in a quartz buxo, pre-boiled in concentrated hydrochloric acid, washed with distilled water, alcohol, ether and dried. Buxu lid and packaged in aluminum foil. On the strip of obessilennaya filter («blue ribbon») size 5x15 mm nakatyvaet 0.1 cmstandard solution europium. After nakapyvaniya each drop of the solution the filter was dried on the hot plate. The dried filter with the applied standard solution europium, wrapped in aluminum foil (reference). The sample and the reference sample tag, placed in a single aluminum case (small block), rinsed with acetone or ethyl alcohol and irradiated in a nuclear reactor for 20 hours with a neutron flux of (1−3)·10on natural hair./cm·C. the transportation of the irradiated sample and the reference sample, in accordance with the requirements of OSP-72, is in lead transport containers of the type TC (TC-80, TC-150) on a special machine.
Quartz buxo the irradiated sample is placed behind a protective shield of lead bricks and lead glass. Forceps remove aluminum foil, open the lid and the irradiated sample is dissolved in hot 7 mol/DMhydrochloric acid. The solution was transferred to a capillary glass with a capacity of 50 cm. Buxu washed with hot 7 mol/DMhydrochloric acid 3 or 4 times. Rinse solutions are transferred with a capillary into the same beaker. The solution is evaporated almost to dryness, the REE chlorides are dissolved in 2 cmof 0.1 mol/DMhydrochloric acid and passed through an extraction-chromatographic column N 2, pre-washed in 0.1 mol/DMhydrochloric acid. Engineering work on the column sec. 3 23862.7 GOST-79.
The beaker containing the sample solution, washed with 5 cmof 0.1 mol/DMhydrochloric acid. Flushing solution passed through the column. The first 40 cmof the eluate (including the volume of sample and wash solution) is collected in the measuring cylinder capacity of 50 cm, then the eluate is collected into jars with a capacity of 18 cmin portions of 5 cmand determine the presence of sodium-24 in every portion of the radioactivity measurement solution for semiconductor gamma-spectrometer for 1−5 minutes in the Absence of controlled portions of sodium-24, when measured within 5 min, indicating complete elution from the column.
After complete elution of sodium-24 is passed through a column of 1 mol/DMhydrochloric acid; 40 cmeluate is discarded and then the eluate is collected into jars with a capacity of 18 cmin portions of 3 cmand determine the per serving the presence of europium-152 and 152measurement of radioactivity of the solution on a semiconductor gamma-spectrometer for 1−5 minutes in the presence of a controlled portion of the europium-152 15230 cmeluate is collected in a measuring cylinder with a capacity of 100 cm(the main fraction of europium). Then the eluate is collected into jars with a capacity of 18 cmin portions of 3 cmand determine the per serving the presence of europium-152 and 152measurement of radioactivity of the solution on the gamma spectrometer. All the portions containing the europium-152 and 152, is added to the main portion of the europium (graduated cylinder), is evaporated in a glass evaporator to a volume of 10−15 cm, carried over to buxu with a capacity of 18 cmand is evaporated to a volume of 1 cm(fraction of europium).
Next, using a column flow of 150 cm7 mol/DMof hydrochloric acid and 25 cmof 0.1 mol/DMhydrochloric acid. The eluates discarded.
The irradiated reference sample free from aluminum foil behind the protective shield of lead bricks and lead glass was placed in a glass buxu with a capacity of 18 cm, 0.5 cm pourhot concentrated nitric acid and after the destruction of the paper added 0.5 cmof distilled water. The fraction of europium and the reference sample are measured on the semiconductor
m gamma spectrometer (see section 4.3).
4.3. Measurement of radioactivity
Before measuring gamma-ray spectrometer will graduate in energy using standards of gamma-ray emitters set OSGI. When the graduation is chosen such amplification of signals from the detector to one channel of the analyzer had of 0.8−1 Kev.
In the controlled portions of the presence of the designated element is set by measuring each of these portions of the gamma-ray spectrometer for 1−5 min.
The definition of controlled elements carried out in the main botopical in the spectrum of sodium — sodium-24 (1368 Kev), lanthanum — lanthanum-140 (1596,5 Kev), praseodymium — praseodymium-142 (1576 Kev), neodymium — neodymium-147 (91 Kev) of promethium — promethium-147 (91 Kev), samarium — samarium-153 (103 Kev), europium — europium-152 152(122 Kev).
To determine the content of impurities in the sample solutions containing fraction determined elements measured by gamma-spectrometer in series with the comparison samples in the same geometric conditions and determine the area of the main fotopic in the spectra of the measured fraction and the reference sample.
The fraction of praseodymium-neodymium measured at a distance of 8 cm from the detector (height) with lead and aluminum filters (11 and 2 mm, respectively). Sample comparison of praseodymium measured in the same conditions.
The definition of the area of the main fotopic in the spectrum (), imp., carried out using a set of mathematical operations analyzer or graphical way after the recording of the spectrum on paper and calculated by the formula
,
where is the area of the main fotopic and background the Compton distribution underneath, imp.;
— the number of channels of the main fotopic;
, — the number of channels on the left and right of the main fotopic accepted for calculation of the background;
, — reference -Ohm or -Ohm channel, imp.
The number of channels of the main photopia limited to the left channel, in which the number of pulses different from the number of pulses in the subsequent channel is not less than 2, the right — the channel in which the number of pulses different from the number of pulses in the previous channel is not less than 2.
Time measuring the area of the main fotopic sample is determined by the actual content of impurities in the measured fraction is 1−100 min. Measurement is continued until until the number of pulses corresponding to the area of the main fotopic, would not be equal to 1000. In the case where the area of the main fotopic exceed 1000 pulses/min, the solution was diluted to measure the activity of the aliquot.
5. PROCESSING OF THE RESULTS
5.1. Mass fraction of impurities of oxides of REE in the sample () in percent is calculated by the formula
,
where is the mass of the oxide of the element in the reference sample, g;
— the area of the main fotopic in the spectrum of the reference sample, imp.;
— the area of the main fotopic in the spectrum of the measured fraction, imp.;
— hanging samples in the calculation of the oxide, g;
— the measurement of the activity of the reference sample, min;
— the measurement activity of the sample, min.
5.2. The discrepancy between the results of two tests (a ratio greater outcome to a lesser) should not exceed the value of permissible differences, is equal to 2.5.