ISO 10204:1992 pdf free download.Iron ores — Determination of magnesium content — Flame atomic absorption spectrometric method.
ISO 10204 specifles a flame atomic absorption spectrometric method for the determination of the magnesium content of iron ores.
This method Is applicable to magnesium contents between 0,01 % (rn/rn) and 3,0 % (rn/rn) In natural iron ores, iron ore concentrates and agglomerates, Including sinter products.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of ISO 10204. At the time of publication, the editions Indicated were valid. All standards are sublect to revision, and parties to agreements based on ISO 10204 are encouraged to Investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
ISO 648:1977, Laboratory glassware — One-mark plpettes.
ISO 1042:1983, Laboratory glassware — One-mark volumetric flasks.
ISO 3081:1986, Iron ores — Increment sampling — Manual method.
ISO 3082:1987, Iron ores — Increment sampling and sample preparation — Mechanical method.
ISO 3083:1986, Iron ores — Preparation of samples
— Manual method.
ISO 7764•1985. Iron ores — Preparation of predried test samples for chemical analysis.
4.7 Background solution.
Dissolve 10 g of pure iron wire [minimum purity 99,9 % (rn/rn), of magnesium content less than
00002 % (rn/rn)] in 50 ml of hydrochloric acid (4.2) and oxidize by adding nitric acid (4.4) drop by drop. Evaporate until a syrupy consistency Is obtained. Add 20 ml of hydrochloric acid (4.2) and dilute to 200 ml with water. Dissolve 17 g of sodium carbonate (4.1) In water, add carefully to the iron solution and heat to remove carbon dioxide. Transfer the cooled solution to a 1 000 ml one-mark volumetric flask, dilute to volume with water and mix.
4.8 Lanthanum chloride solution.
Dissolve 50 g or lanthanum chloride (LaCI3.xH2O) [of magnesium content less than 0,002 % (rn/rn)] in 50 ml of hydrochloric acid (4.2) and 300 ml of hot water. Cool and dilute to I litre.
4.9 MagnesIum standard solution. 15 i’g Mg/mi.
Dissolve 0300 0 g of oxide-Free magnesium metal [minimum purity 99.9 % (rn/rn)] by slowly adding 75 ml of hydrochloric acid (p 1,19 g/ml), diluted I + 3. When dissolved, cool, transfer to a 1 000 ml one-mark volumetric flask, dilute to volume with water and mix. Transfer 10 ml of this solution to a 200 ml one-mark volumetric flask, dilute to volume with water and mix.
4.10 Magnesium calibration solutions.
Using pipettes, transfer 2,0 ml; 5,0 ml; 10,0 ml:
20,0 ml; 40,0 ml; and 50,0 ml portions of the magnesium standard solutions (4.9) to 200 ml volumetric flasks (see note 2). Add 6 ml of hydrochloric acid (4.2), 60 ml of background solution (4.7) and 40 ml of lanthanum chloride solution (4.8) to each flask. Dilute all the solutions to volume with water and mix. Prepare a zero magnesium calibration solution by transferring 60 ml of the background solution to a 200 ml volumetric flask, add 8 ml of hydrochloric acid (4.2) and 40 ml of lanthanum chloride solution. Dilute all the solutions to volume with water and mix.
NOTE 2 The range of magne&um which can be covered may vary from Instrument to instrument. Attention should be paid to the minimum criteria given In 5.3. For instruments having high sensitivity, smaller portions of standard solution or a more dliu(ed standard solution can be usod.
5 Apparatus
Ordinary laboratory apparatus, inIudirig one-mark pipettes and one-mark volumetric flasks complying with the specifications of ISO 648 and ISO 1042 respectIvely, and
5.1 PlatInum crucible, of minimum capacity 30 ml.
5.2 Muffle furnace, capable of maintaining a temperature of approximately 1100 °C.
5.3 Atomic absorption spectrometer, equipped with an air-acetylene burner.
The atomic absorption spectrometer used In this method shall meet the following criteria.
a) Minimum sensitivity — the absorbance of the most concentrated magnesium calibration solutIon (4.10) shall be at least 0.3.
b) Graph linearity — the slope of the calibration graph covering the top 20 % of the concentration range (expressed as a change In absorbance) shall not be loss than 0,7 of the value of the slope for the bottom 20 % of the concentration range determined in the same way.
C) Minimum stability —the standard deviation of the absorbance of the most concentrated calibration solution and that of the zero calibration solution, each being calculated from a sufficient number of repetitive measurements, shall be less than 1,5 % and 0,5 % respectively of the mean value of the absorbance of the most concentrated calibration solution.
NOTES
3 The use of a strip chart recorder and/or digital readout device is recommended to evaluate criteria a) b) and c) and for all subsequent measurementS.
4 Instrument parameters may vary with each instrument. The following parameters were successfully used In several laboratories and they can be used as guidelines. An air-acetylene flame was used.
Hollow cathode lamp, mA 15
Wavelençjth, nm 285,2
Air flow rate, 11mm 22
Acetylene flow rate, 11mm 4.2
In systems where the values shown above for gas flow rates do not apply, the ratio of the gas flow rates may still be a useful guideline.
6 Sampling and samples
6.1 Laboratory sample
For analysis, use a laboratory sample of minus 100 jim particle size which has been taken In accordance with ISO 3081 or ISO 3082 and prepared in accordance with ISO 3082 or Iso 3083. In the case of ores having significant contents of combined water or oxidizable compounds, use a particle size of minus 180 jim.
NOTE 5 A guideline on significant contents of combined water and oxidizable compounds is incorporated in Iso 7764.
6.2 PreparatIon of predried test samples
Thoroughly mix the laboratory sample and, taking multiple increments, extract a test sample In such a way that It is representative of the whole contents of the container. Dry the test sample at 105 C ± 2 nC, us specified in ISO 7704. (ThIs is the predried test sample.)
7 Procedure
7.1 Number of determinations
Carry out the analysis at least in duplicate in accordance with annex A. independently, on one predried test sample.
NOTE C The uxpiusivn 9ndupedeiihly” enuaIi that the second and any subsequent result Is not affected by the previous result(s). For this particular analytical method. this condition implies that the repetition of the procedure is carried out either by the same operator at a different time or by a different operator Including. in either case, appropriate recalibration.
7.2 Test portion
Taking several increments, weigh, to the nearest 0,000 2 g, approximately 1 g of the predried test sample obtained in accordance with 6.2.
NOTE 7 The test portion should be taken and weighed quickly to avoid reabsorption of moisture.
7.3 Blank test and check test
In each run, one blank test and one analysis of a certified reference material of the same type of ore shall be carried out In parallel with the analysis of the ore sample(s) under the same conditions. A predried test sample of the certified reference material shall be prepared as specified In 6.2.
NOTE 8 The certified reference material should be of the same type as the sample to be analysed and the properties of the two materials should bo sufficiently similar to ensure that In either case no significant changes in the analytical procedure will become necessary.
When the analysis Is carried out on several samples at the same time, the blank value may be represented by one test, provIded that the procedure is the same and the reagents used are from the same reagent bottles.
When the analysis is carried out on several samples of the same type of ore at the same time, the analytical value of one certified reference material may be used.
A Is the result or the mean of results obtained for the certified reference material;
Is the between-laboratories standard deviation of the certifying laboratories;
is the within-laboratory standard deviation of the certifying laboratories:
Is the average number of replicate determinations In the (urtI1ylI1J laboratories;
N Is the number of certifying laboratories;
is the number of replicate determinations on the reference material (in most cases n 1);
0L and ar are as defined in 8.2.1.
If condItion (6) is satisfied, I.e. If the left-hand side is less than or equal to the right-hand side, then the difference A—Aj Is statistically Insignificant; othe.rwice. it lq statistically signIficant.
When the difference Is significant, the analysis shall be repeated, simultaneously with an analysis of the test sample. If the difference Is again significant, the procedure shall be repealed using a different certified reference material of the same type of ore.
When the range of the two values for the test sample is outside the limit for r calculated according to equation (2) in 8.2.1, one or more additional tests shall be carried out In accordance with the flowsheet presented in annex A, simultaneously with an analysis of a certified reference material of the same type of ore.
Acceptability of the results for the test sample shall in each case be subject to the acceptability of the results for the certified reference material.
NOTE 12 The following procedure should be used when the Information on the reference material certificate is inconipiete:
a) If there are insufficient data to enable the between- laboratories standard deviation to be estimated, delete the expreselor 4jn, and regard s as the standard deviation of the laboratory means;
b) if the certification has been made by only one laboratory or if the Interlaboratory results are missing, ills advisable that this material not be used In the application of the standard. In case its use is unavoidable, use the condition.