BS/EN 10177-2019 pdf download.Steels – Determination of calcium content – Flame atomic absorption spectrometric method (FAAS).
Weigh (2.500 ± 0,001) g of pure calcium carbonate, dried at 105°C and transfer into glassware of suitable size. Add 20 ml of water and then, slowly. 20 ml of hydrochloric acid (5.2).
When dissolved, dilute to 100 ml approximately with water and transfer the solution quantitatively into
a 1 000 ml one-mark volumetric flask Dilute to the mark with water and mix.
1 ml of this solution contains 1 mg of calcium.
5.6 Calcium standard solution, 0,02 g/l.
Transfer 5,0 ml of calcium standard solution (5.5) into a 250 ml one-mark volumetric flask. Dilute to the
mark with water and mix.
Prepare this solution immediately prior to use.
1 ml of this solution contains 0,02 mg of calcium.
5.7 Calcium standard solution, 0.002 g/l.
Transfer 20,0 ml of calcium standard solution (5.6) into a 200 ml one-mark volumetric flask Dilute to
the mark with water and mix.
Prepare this solution immediately prior to use.
1 ml of this solution contains 0.002 mg of calcium.
5.8 Iron base solutIon. 50 g/L
Weigh, to the nearest 0,01 g., 10,00 g of pure iron (5.1) and transfer into a heat-resistant glassware of suitable size. Add 100 ml of hydrochloric acid (5.2), cover the glassware with a watch glass and heat gently until the reaction ceases. Oxidize with 25 ml of nitric acid (5.3) and then boll the solution for 5 mm to remove nitrogen oxides.
Allow to cool and transfer the solution quantitatively into a 200 ml one-mark volumetric flask. Add 2,5 ml of potassium chloride (5.4). dilute to the mark with water and mix.
6 Apparatus
6.1 Ordinary laboratory apparatus
All volumetric glassware shall be class A. in accordance with EN ISO 648 or EN ISO 1042, as appropriate.
All glassware shall be washed in hydrochloric acid (5.2) and then in water. The quantity of calcium present in the glassware and the volumetric flasks can be checked by measuring the absorption of distilled water introduced in the glassware after the acid washing.
6.2.1 General
The spectrometer shall be equipped with a calcium hollow-cathode lamp or other suitable radiation source and supplied with acetylene and nitrous oxide sufficiently pure to give a steady clear fuel-lean flame, free from water and oil, and free from calcium.
The atomic absorption spectrometer used will be satisfactory if, after optimization according to 8.3.4, the limit of detection and characteristic concentration are in reasonable agreement with the values given by the manufacturer and it meets the performance criteria given in 6.2.2 and 6.2.3.
6.2.2 Minimum precision
The standard deviation of 10 measurements of the absorbance of the most concentrated calibration solution shall not exceed 3 % of the mean absorbance of this solution.
The standard deviation of 10 measurements of the absorbance of the least concentrated calibration solution (excluding the zero member) shall not exceed I % of the mean absorbance of the most concentrated calibration solution.
6.2.3 Additional performance requirements
6.2.3.1 General
The instrument should also conform to the additional performance requirements given In 6.2.3.2 and
6.2.3.3.
6.2.3.2 Characteristic concentration
The characteristic concentration for calcium in a matrix similar to the final test solution shall be lower than 0,05 pg/mI.
6.2.3.3 Limit of detection
The limit of detection Is a number, expressed in units of concentration (or amount) that describes the lowest concentration level (or amount) of an element that can be determined to be statistically different from an analytical blank
The limit of detection of calcium in a matrix similar to the final test solution shall be less than 0,025 pgJml.
7 Sampling
Carry out sampling in accordance with EN ISO 14284 or appropriate national standards for steels.
Degrease the chips with any appropriate solvent (acetone, ethyl ether. etc.), avoiding contamination of the sample when handling.
8.3.1 Preparation of the test solution
Transfer the test portion (8.1) into a 400 ml beaker. Add 20 ml of hydrochloric acid (5.2), cover the beaker with a watch glass and heat gently until the acid action ceases.
Oxidize with 5 ml of nitric acid (5.3) and then boil the solution for 5 mm to remove nitrogen oxides. 8.3.2 Treatment of the test solution
8.3.2.1 Calcium contents up to 0,006 %
Allow to wol and transfer the test solution quantitatively into a 100 ml one-mark volumetric flask.
WARNING — Do not filter, unless absolutely necessary. If unavoidable, use only filters known to be calcium free.
Add 0,5 ml of potassium chloride (5.4), dilute to the mark with water and mix.
For test solutions giving a calcium absorbance greater than about 0,6. the test solution should be diluted and compared with calibration solutions diluted In the same way. These more diluted solutions should also be used if problems with burner blockage are encountered.
8.3.2.2 Calcium contents between 0,004 % and 0,012 %
Allow to cool and transfer the test solution quantitatively into a 200 ml one-mark volumetric flask WARNING — Do not filter, unless absolutely necessary. If unavoidable, use only filters known to be calcium free.
Add 095 ml of potassium chloride (5.4), dilute to the mark with water and mix.
For Lest solutions giving a calcium absorbance greater than about 0,6. the test solution should be diluted and compared with calibration solutions diluted In the same way. These more diluted solutions should also be used if problems with burner blockage are encountered.
8.3.3 Preparation of the calibration solutions
8.3.3.1 General
Table 1 and Table 2 contain typical sets of calibration solutions. The range of concentrations in a set of solutions may be changed in order to better bracket the expected sample solution concentration.
8.3.3.2 CalcIum contents up to 0,006 % (mass fraction)
Into each of a series of 50 ml one-mark volumetric flasks. introduce the volumes of calcium standard solution (5.7) shown in Table 1 and 20 ml of the iron base solution (5.8). Dilute to the mark with water and mix.BS/EN 10177-2019 pdf download.