GOST 12364-84
GOST 12364−84 Steel alloyed and high alloy. Methods for the determination of cerium
GOST 12364−84
Group B39
STATE STANDARD OF THE USSR
STEEL ALLOYED AND HIGH-ALLOYED
Methods for the determination of cerium
Steels alloyed and highalloyed. Methods for the determination of certium
AXTU 0809
Valid from 01.01.85
to 01.01.95*
______________________________
* Expiration removed
Protocol N 4−93 inter-state Council
for standardization, Metrology and certification
(IUS N 4, 1994). — Note the CODE.
DEVELOPED by the Ministry of ferrous metallurgy of the USSR
PERFORMERS
N. P. Liakishev, V. T. Ababkov, S. M. Novokshenova, M. S. Dimova, R. D. Malinin, E. D. Shuvalov, T. N. Artemova
INTRODUCED by the Ministry of ferrous metallurgy of the USSR
Member of the Board V. G. Antipin
APPROVED AND put INTO EFFECT by decision of the USSR State Committee on standards of 19 January 1984
N 232
REPLACE GOST 12364−66
This standard sets the photometric method for the determination of cerium (with a mass fraction of from 0.002 to 0.05%), amperometric method for the determination of cerium (with a mass fraction of from 0.005 to 0.2%) in the alloy and high-alloy steels.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 20560−81.
2. PHOTOMETRIC METHOD
2.1. The essence of the method
The method is based on the ability of cerium (IV) oxidizing orthotolidine in sulfuric acid medium to form a yellow colored compound and subsequent measurement of optical density on the spectrophotometer at a wavelength of 434 nm or photoelectrocolorimeter with a filter having a region of transmittance in the wavelength interval from 410 to 480 nm.
Cerium is separated from the main components of the steel by precipitation in the form of fluoride, with subsequent reprecipitation as the oxalate.
As a collector use lanthanum.
2.2. Apparatus, reagents and solutions
Spectrophotometer, photoelectrocolorimeter, or spectropolarimeter.
Thermometer.
Hydrochloric acid by the GOST 3118−77 and diluted 1:1, 1:20.
Nitric acid GOST 4461−77.
Sulfuric acid GOST 4204−77 and diluted 1:1.
A mixture of hydrochloric and nitric acids, freshly made: to 150 cm
of hydrochloric acid pour 50 cmof nitric acid and stirred.
Ammonia water according to GOST 3760−79.
Oxalic acid, saturated solution with a mass concentration of 100 g/land diluted with the mass concentration of 10 g/DM
Sodium fluoride according to GOST 4463−76, solutions with a mass concentration of 35 and 2 g/DM.
Ammonium fluoride according to GOST 4518−75, solutions with a mass concentration of 35 and 2 g/DM
Boric acid according to GOST 9656−75, a saturated solution at 50 °C.
A mixture of boric and hydrochloric acids: 300 cmof boric acid solution flow of 500 cmof hydrochloric acid, 1200 cmof water and stirred.
The lanthanum nitrate solution with a mass concentration of 10 g/DMof 10 g of lanthanum nitrate dissolved in 200 cmof hydrochloric acid (1:20) when heated. The solution was filtered through a medium density filter «white ribbon» in a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.
Carbonyl iron brand PS according to GOST 13610−79.
Orthotolidine, a solution with a mass concentration of 0.5 g/DM. 0.05 g of orthotolidine dissolved in 20 cmhot sulphuric acid (1:1) under heating. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.
Wash solution: to 50 cmof water poured 10 drops of sulfuric acid, 5 cmsolution orthotolidine, made up to 100 cmwater, and stirred.
Universal indicator paper pH 1−10.
Cerium nitrate, OS. h
Standard solutions of cerium.
Solution a: 3.1 g of cerium nitrate CE (NO
)·6H
O were placed in a glass with a capacity of 200−250 cm, poured 60−70 cmwater, 5 cmof nitric acid and heated until complete dissolution. The solution was cooled, filtered through a medium density filter «white ribbon» in a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.
1 cmof a standard solution And contains approximately 0.001 g of cerium.
The mass concentration of cerium in 1 cmof the solution And sets the gravimetric method.
For this aliquot part of the 50 cmnitrate solution of cerium were placed in a glass, pour 5 cmof hydrochloric acid and the solution was evaporated to wet salts. Add 40 cmof a saturated solution of oxalic acid, boil for 3−4 min and then allowed to stand for 12 h
The precipitate was filtered off on a double thick filter «blue ribbon» and the average density of the «white ribbon» with the addition of a small amount of ashless paper pulp.
The glass and the filter cake was washed 5−6 times with a weak solution of oxalic acid. The filter with precipitate was placed in a calcined to constant weight and weighed porcelain crucible, dried, incinerated at 400−450 °C, calcined at 800 °C for 1 h, cooled and weighed.
The mass concentration of a standard solution of cerium (
), g/cm, is calculated by the formula
,
where 
is the mass of the crucible with the precipitate of cerium dioxide, g;
— weight of crucible without precipitate cerium dioxide, g;
— the mass of the crucible with the sediment in the reference experiment, g;
— weight of crucible without sediment in the reference experiment, g;
0,8141 — the ratio of cerium dioxide on cerium;
— the amount of cerium nitrate solution, taken for installation of the mass concentration of the solution of cerium cm.
Solution B: 25 cmstandard solution And transferred to a volumetric flask with a capacity of 250 cm, made up to the mark with water and mix.
1 cmof a solution contains 0.0001 g of cerium.
Solution: 25 cmstandard solution B is transferred to a volumetric flask with a capacity of 250 cm, made up to the mark with water and mix.
1 cmof the solution contains 0,00001 g of cerium.
Distilled water that does not contain WITH. Water boiled for 1 h and cooled in the flask, closed tube with a V-shaped tube filled with soda]
estu.
2.3. Analysis
2.3.1. Take the hitch weight of steel in accordance with table. 1 and placed in a glass or flask with a capacity of 250 cm, 30−40 cm, pour themixture of hydrochloric and nitric acids. Beaker cover watch glass, and dissolve a portion with a moderate heat.
The solution was cooled, washed the glass and the side of the Cup with 3−5 cmof water and evaporated to moist salts. The contents of the glass poured 5−7 cmof hydrochloric acid and again evaporate the solution to wet salts. Pour 5 cmof hydrochloric acid and dissolve the contents of the glass when heated. Then pour 60 cmof water, add a small amount of ashless paper pulp, 5 cmof a solution of lanthanum nitrate, 60−70 cmof a solution of sodium fluoride with a mass concentration of 35 g/DM. If the steel contains more than 3% of aluminum, add 80−100 cmof a solution of sodium fluoride. If the steel contains titanium, tungsten or niobium, add 60−70 cmof a solution of ammonium fluoride with a mass concentration of 35 g/DM.
Table 1
| |
|
|
|
|
|
| The mass fraction of cerium, % |
The weight of steel, g
|
| From |
0,002 |
to |
0,005 |
incl.
|
Of 1.00 |
| SV. |
0,005 |
« |
0,01 |
«
|
0,50 |
| « |
0,01 |
« |
0,02 |
«
|
0,25 |
| « |
0,02 |
« |
0,05 |
«
|
0,10 |
Solution and the precipitate was allowed to stand for 40−45 minutes, stirring occasionally.
The precipitate of fluoride is filtered off on a double thick filter «blue ribbon» and the average density of the «white ribbon», washed 6−7 times with a solution of sodium fluoride or ammonium mass concentration of 2 g/DM. The filtrate is discarded. The filter cake is dissolved in 120 cmhot mixture of boric and hydrochloric acids (in portions of 20 cm), collecting the solution in the beaker or flask in which he carried out the deposition of fluorides. The filter was washed 5−6 times with hot water, adding the wash liquid to the main filtrate. The filter is discarded.
The solution was evaporated to wet salts. The side of the Cup washed with 30−40 cmof water and dissolve the contents of the glass when heated. Poured 30 cmof a saturated solution of oxalic acid and ammonia solution to a pH of 2 by universal indicator with vigorous stirring. Solution and the precipitate was heated to boiling, incubated at 85−90 °C for 30−40 min, dilute with water to 120 cmand cooled. After 12−18 h, the precipitate of oxalates is filtered on a double filter of dense «blue ribbon» and the average density of the «white ribbon» with the addition of a small amount of ash-free mass, washed 5−6 times with a weak solution of oxalic acid. The filtrate is discarded. The filter with precipitate was placed in a porcelain crucible, dried, incinerated at 400−450 °C, calcined at 800 °C for 1 h and cooled.
The crucible with the precipitate of ceria was calcined immediately before the determination of cerium with orthotolidine.
To the contents of a crucible add 10 drops of hot sulphuric acid, thoroughly rubbed dry with a glass rod for 2 minutes, add 3 cmof a solution of orthotolidine again stirred for 1 min, pour 5 cmof water. The solution was filtered through cotton wool, previously washed with flushing solution in a volumetric flask with a capacity of 50 cm, washed the crucible and cotton 3−4 times the water, add the solution to the mark with water and mix.
Measure the optical density of the solution on the spectrophotometer at a wavelength of 434 nm or photoelectrocolorimeter with a filter having a region of transmittance in the wavelength interval from 410 to 480 nm in a cuvette with a layer thickness of 30 mm after 5 min after the addition of orthotolidine. Coloration is stable for 5−10 min In a solution of comparison, use water. Simultaneously conduct control experience for contamination of reagents.
The cerium content is found by a calibration graph with amendments the control ops
TA.
2.3.2. Construction of calibration curve
Seven of cups or flasks with a capacity of 250−300 cmis placed hinge steel similar in composition, but not containing cerium, in accordance with the table. 1. Six of cups or flasks poured consistently 1, 2, 3, 4, 5, 6 cmstandard solution B. the Seventh glass is used for the reference experiment.
All the glasses are poured at 30 cmof a mixture of hydrochloric and nitric acids, beakers cover watch glass, and dissolve the sample in moderate heat.
Then do as mentioned in paragraph 2.3.1.
From the values of absorbance of analyzed solutions is subtracted the value of optical density in the reference experiment.
The found values of optical density of solutions and relative concentrations of cerium build the calibration graph.
2.4. Processing of the results
2.4.1. Mass fraction of cerium (
) in percent is calculated by the formula
,
where 
is the mass of cerium was found in the calibration schedule g;
the weight of steel,
2.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level 
= 0.95 does not exceed the values given in table. 2.
Table 2
| |
|
|
|
|
|
The mass fraction of cerium, %
|
Allowable absolute differences, % |
| From |
0,002 |
to |
0,005 |
incl.
|
0,002 |
| SV. |
0,005 |
« |
0,010 |
«
|
0,005 |
| « |
0,010 |
« |
0,020 |
«
|
0,007 |
| « |
0,020 |
« |
0,05 |
«
|
0,010 |
| « |
0,05 |
« |
0,1 |
«
|
0,020 |
| « |
0,1 |
« |
0,2 |
«
|
0,040 |
3. AMPEROMETRIC METHOD
3.1. The essence of the method
The method is based on titration of cerium (IV) solution of double sulphate salts of protoxide of iron — ammonium sulfate medium for the amperometric unit with two platinum electrodes at a potential of 0.5 V or platinum and calomel electrodes at a potential of 0.9 volts at a current of oxidation of excess iron ions (II).
Cerium ((III) is oxidized to cerium (IV) potassium permanganate, followed by reduction of its surplus atomistically sodium and binding of the latter with urea.
Cerium is separated from the main components of the steel by precipitation in the form of fluoride, with subsequent reprecipitation as the oxalate. As a collector use lanthanum.
3.2. Apparatus, reagents and solutions
Amperometric unit with two platinum electrodes or with platinum and calomel electrodes.
Hydrochloric acid by the GOST 3118−77 and diluted 1:1, 1:20.
Nitric acid GOST 4461−77.
Sulfuric acid GOST 4204−77 and diluted 1:1.
A mixture of hydrochloric and nitric acids freshly prepared: to 150 cmof hydrochloric acid pour 50 cmof nitric acid and stirred.
Ammonia water according to GOST 3760−79.
Sodium fluoride according to GOST 4463−76, solutions with a mass concentration of 35 and 2 g/DM.
Ammonium fluoride according to GOST 4518−75, solutions with a mass concentration of 35 and 2 g/DM.
Boric acid according to GOST 9656−75, a saturated solution at 50 °C.
A mixture of boric and hydrochloric acids: 300 cmof boric acid solution flow of 500 cmof hydrochloric acid, 1200 cmof water and stirred.
Sodium volframovich 2-water according to GOST 18289−78, a solution with a mass concentration of 10 g/DMof tungsten: 17,94 g volframovich sodium is placed in a beaker, dissolve in 200−250 cmof water is added with stirring 15 g of sodium hydroxide.
The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.
Potassium pyrophosphate, solution with the mass concentration of 800 g/DM.
Sodium hydroxide according to GOST 4328−77.
The lanthanum nitrate solution with a mass concentration of 10 g/DMof 10 g of lanthanum nitrate dissolved in 200 cmof hydrochloric acid (1:20) when heated. The solution was filtered through a medium density filter «white ribbon» in a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.
Potassium dichromate according to GOST 4220−75, the solution with the mass concentration of chromium 10 g/DM: 28,29 g of potassium dichromate dissolved in 150−200 cmof water, poured 90 cmof sulphuric acid (1:1) and add in small portions 50 g sulphurous acid sodium until the solution colour from orange-yellow to green. Then gently boiled to remove the excess sulfur dioxide. The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.
Titan GOST 19807−77, a solution with a mass concentration of titanium 1 g/DM: 1 g of metallic titanium were placed in a glass, pour 10−20 cmof water 100 cmof sulphuric acid (1:1) and dissolved by heating. After complete dissolution of the sample flow 3 to 5 drops of nitric acid, evaporated to release vapors of sulfuric acid, cooled, washed the side of the Cup with water, again evaporated to release vapors of sulfuric acid and cooled. The solution is poured into a measuring flask with a capacity of 1 DM, pour 100 cmof sulphuric acid (1:1), cooled, made up to the mark with water and mix.
Palixid of vanadium, the solution with a mass concentration of vanadium to 1 g/DM: 1,7852 g perioxide vanadium, previously calcined at 400−500 °C to constant weight, is placed in a beaker, add 50 cmof sulfuric acid and heated to dissolve sample. Then carefully pour 5 cmof nitric acid and evaporated to release vapors of sulfuric acid.
The solution was cooled, washed walls of glass with water and again evaporated to release vapors of sulfuric acid. Salt is dissolved in 200−250 cmof water by heating, the solution was filtered through a medium density filter «white ribbon» in a volumetric flask with a capacity of 1 DM. The filter was washed 4−5 times with hot water. To the solution in the flask is poured with stirring 100 cmof sulphuric acid (1:1), the Solution was cooled, diluted to the mark with water, mix.
Carbonyl iron brand PS according to GOST 13610−79.
Potassium permanganate according to GOST 20490−75, solution with molar concentration of the equivalent 0,1 mol/DM.
Sodium atomistically according to GOST 4197−74, a solution with a mass concentration of 40 g/DM.
Urea according to GOST 6691−77, a solution with a mass concentration of 100 g/DM.
Oxalic acid, saturated solution with a mass concentration of 100 g/land diluted with the mass concentration of 10 g/DM.
Sanitarily anhydrous sodium GOST 195−77.
Hydrogen peroxide according to GOST 10929−76.
Cerium nitrate, OS. h
Standard solutions of cerium.
Solution a: 3.1 g of cerium nitrate, CE (NO)· 6HO were placed in a glass with a capacity of 200−250 cm, poured 60−70 cmwater, 5 cmof nitric acid and heated until complete dissolution. The solution was cooled, filtered through a medium density filter «white ribbon» in a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.
1 cmof a standard solution And contains approximately 0.001 g of cerium.
The mass concentration of cerium in 1 cmof the solution And sets the gravimetric method.
For this aliquot part of the 50 cmnitrate solution of cerium were placed in a glass, pour 5 cmof hydrochloric acid and the solution was evaporated to wet salts. Add 40 cmof a saturated solution of oxalic acid, boil for 3−4 min and then allowed to stand for 12 h
The precipitate was filtered on a double filter of dense «blue ribbon» and the average density of the «white ribbon» with the addition of a small amount of ashless paper pulp.
The glass and the filter cake was washed 5−6 times with a weak solution of oxalic acid. The filter with precipitate was placed in a calcined to constant weight and weighed porcelain crucible, dried, incinerated at 400−450 °C, calcined at 800 °C for 1 h, cooled and weighed.
The mass concentration of a standard solution of cerium (
), g/cm, is calculated by the formula
,
where is the mass of the crucible with the precipitate of cerium dioxide, g;
— weight of crucible without precipitate cerium dioxide, g;
— the mass of the crucible with the sediment in the reference experiment, g;
— weight of crucible without sediment in the reference experiment, g;
0,8141 — the ratio of cerium dioxide on cerium;
— the amount of cerium nitrate solution, taken for installation of the mass concentration of the solution of cerium cm.
Solution B: 25 cmstandard solution And transferred to a volumetric flask with a capacity of 250 cm, made up to the mark with water and mix.
1 cmof a solution contains 0.0001 g of cerium.
Solution: 25 cmstandard solution B is transferred to a volumetric flask with a capacity of 250 cm, made up to the mark with water and mix.
1 cmof the solution contains 0,00001 g of cerium.
Salt of protoxide of iron and ammonium double sulfate (salt Mora) according to GOST 4208−72.
The salt solution of oxide of iron and ammonium double sulfate with molar concentration of equivalent of approximately 0,0025 mol/DM: 1 g of salt of oxide of iron and ammonium double sulfate is placed in a beaker and dissolved in 200−250 cmof water, carefully pour 50 cmof sulphuric acid, cool, add water to 1 DM, thoroughly mixed and filtered through a medium density filter «white ribbon».
Mass concentration of sulfate double salt of oxide of iron and ammonium establish a standard solution of cerium.
To do this in a glass of injected standard solution of cerium, solutions of titanium, chromium, tungsten, vanadium and the suspension of carbonyl iron in amounts corresponding to their weight in the sample the test sample, pour the 40−50 cmof the mixture of acids and then do as stated in claim 3.3.
Allow setting of the mass concentration of sulfate double-salts of oxide of ammonium standard solution of cerium added to the batches of steel, similar in composition to the test, but not containing cerium.
The analysis is carried out as specified in clause 3.3.
Mass concentration of sulfate double salt of oxide of iron and ammonium (
) in the cerium, g/cm, is calculated by the formula
,
where is the mass of cerium in aliquote part of the standard solution taken for titration, g;
— the volume of a solution of double sulphate salts of protoxide of iron and ammonium used for the titration of a standard solution of cerium, cm;
— the volume of a solution of double sulphate salts of protoxide of iron and ammonium used for the titration of a solution in the reference experiment, cm.
Universal indicator paper pH 1−10.
3.3. Analysis
The weight and steel weight in accordance with table. 3 is placed in a beaker or flask with a capacity of 250 cm, 30−40 cm, pour themixture of hydrochloric and nitric acids, glass cover watch glass, and dissolve a portion with a moderate heat. The solution was cooled, washed the glass and the side of the Cup with 3−5 cmof water and the solution is evaporated to wet salts. The contents of the glass poured 5−7 cmof hydrochloric acid and again evaporate the solution to wet salts. Pour 5 cmof hydrochloric acid and dissolve the contents of the glass when heated. Then pour 60 cmof water, add a small amount of ashless paper pulp, 5 cmof a solution of lanthanum nitrate, 60−70 cmof a solution of sodium fluoride with a mass concentration of 35 g/DM. If the mass fraction of aluminum in the steel in excess of 3%, adding 80−100 cmof a solution of sodium fluoride. If the steel contains titanium, tungsten or niobium, add 60 -70 cmof a solution of ammonium fluoride with a mass concentration of 35 g/DM.
Table 3
| |
|
|
|
|
|
| The mass fraction of cerium, % |
The weight of steel, g
|
| From |
0,005 |
to |
0,05 |
incl.
|
1,0 |
| SV. |
0,05 |
« |
0,1 |
«
|
0,5 |
| « |
0,1 |
« |
0,2 |
«
|
0,25 |
Solution and the precipitate was allowed to stand for 40−45 minutes, stirring occasionally.
The precipitate of fluoride is filtered on a double filter of dense «blue ribbon» and the average density of the «white ribbon», washed 6−7 times with a solution of sodium fluoride or ammonium mass concentration of 2 g/DM. The filtrate is discarded.
The filter cake is dissolved in 120 cmhot mixture of boric and hydrochloric acids (in portions of 20 cm), collecting the solution in the beaker (flask), which was carried out the deposition of fluorides. The filter was washed 5−6 times with hot water, adding the wash liquid to the main filtrate. The filter is discarded.
The solution was evaporated to wet salts. The side of the Cup washed with 30−40 cmof water and dissolve the contents of the glass when heated. Poured 30 cmof a saturated solution of oxalic acid, ammonia solution to a pH of 2 by universal indicator with vigorous stirring. Solution and the precipitate was heated to boiling, incubated at 85−90 °C for 30−40 min, dilute with water to 120 cmand cooled. After 12−18 h, the precipitate of oxalates is filtered on a double filter of dense «blue ribbon» and the average density of the «white ribbon» with the addition of a small amount of ashless paper pulp, washed 5−6 times with a weak solution of oxalic acid. The filtrate is discarded. The filter with precipitate was placed in a porcelain crucible, dried, incinerated at 400−450 °C, calcined at 800 °C for 1 h and cooled.
The precipitate of oxides of cerium and lanthanum was transferred to a glass, pour 5−10 cmof hydrochloric acid of 3−5 cm
of nitric acid and 1−2 cmof hydrogen peroxide and boiled until the dissolution of the oxides of cerium and lanthanum. Poured 8 cmof sulphuric acid (1:1) and evaporated to release vapors of sulfuric acid. The contents of the Cup cool, wash the side of the Cup with water and again evaporated to release vapors of sulfuric acid.
Salt dissolved in 10−15 cmof water when heated, add the solution volume to 25−35 cm.
In a glass, immerse the electrodes, turn on the stirrer and set the voltage to 0.9 V when the titration with platinum and calomel electrodes or 0.5 V with two platinum electrodes. Pour 10 cmof potassium pyrophosphate and stirred solution.
After 10 minutes the solution is poured dropwise a solution of potassium permanganate until the pink color does not disappear within 2 minutes, the Excess potassium permanganate is reduced, priliva dropwise a solution of sodium attestatio, and pour 5 cmof the urea solution.
Mark on graph paper the initial position of the needle of the galvanometer, add from microburette portions of 0.2 and 0.1 cm, and then 0.05 to 0.02 cmof salt solution Mora, is applied to the paper corresponding to each addition of reagent the value of the current. First the galvanometer is stationary and after the equivalence point moving sharply to the right.
Build titration curve: x-axis postpone the consumption of a double sulfate salt of oxide of iron and ammonium, and the y — axis the magnitude of the current. Find the point equivalent to
lennosti.
3.4. Processing of the results
3.4.1. Mass fraction of cerium () in percent is calculated by the formula
,
where mass concentration of a solution of double sulphate salts of protoxide of iron and ammonium cerium concentration, g/cm;
— the volume of a solution of double sulphate salts of protoxide of iron and ammonium, used for titration of test sample, cm;
— the volume of a solution of double sulphate salts of protoxide of iron and ammonium, used for titration of the reference experiment, cm;
the weight of steel, g
.
3.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values given in table. 2.
