ДСТУ Б EN 13639:2015
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EN 13639:2002 - - - -
This European Standard specifies methods for the determination of the total organic carbon content (TOC) in limestone.
The standard describes the reference method and alternative methods which can be considered to be equivalent. In the case of a dispute, only the reference method is used.
Any other methods may be used provided they are calibrated, either against the reference method or against internationally accepted reference materials, in order to demonstrate their equivalence.
This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments).
ISO 3310-1, Test sieves - Technical requirements and testing - Part 1: Test sieves of metal wire cloth.
ISO 11464, Soil quality - Pretreatment of samples for physico-chemical analyses.
3.1 3.2 X DI = n P Q x
a is the probability level
fis the variability (number of degrees of freedom)x0 ■? tf,a
f- 3.1 Number of tests
Where the analysis is one of the series subject to statistical control, determination of the total organic carbon content by a single test shall be the minimum required.
Where the analysis is not part of a series subject to statistical control, the number of tests for determination of the total organic carbon content shall be two (see also 3.3).
In the case of a dispute, the number of tests for determination of the total organic carbon content shall be two (see also 3.3).
3.2 General statistical terms
Repeatability standard deviation - the standard deviation of test results obtained under repeatability conditions where independent test results are obtained with the same method on identical material tested in the same laboratory by the same operator using the same equipment within short intervals of time.
Reproducibility standard deviation - the standard deviation of test results obtained under reproducibility conditions where test results are obtained with the same method on identical material tested in different laboratories with different operators using different equipment.
NOTE Definitions based on ISO 3534-1.
The standard deviations of repeatability and reproducibility are expressed in absolute percent. Determination limit - is the content where its relative uncertainty, which is assigned to a fixed probability level, and defined as the quotient of the half of a two-side prognosis interval and the content to be assigned to the determination limit, is equal to a pre-set value.
1 &XDI c „ 1 ^XDI -4i if - - = —— - k x D i n - Qx =E( X / -*) 2
/■?=1
p - - t f a - x Dt - Ax d/ - 3.3 3.4 3.5 S z0 is the standard deviation of the procedure t fa is the quantile of the t-distribution (f = n -2) x is the analyzed content assigned to a calibration sample
x is the arithmetic mean of the contents assigned to all calibration samples
x DI is the determination limit
Ax D/ is half width of the two-side prognosis interval
NOTE This determination limit is based on DIN 32645.
3.3 Expression of masses and results
Express masses in grams to an accuracy of Express the results, as a percentage to at least two decimal places If the difference between the individual test results exceeds two times the repeatability standard deviation given in clause 10, the test shall be repeated.
3.4 Blank determinations
Carry out a blank determination without a sample following the same procedure and using the same amounts of reagents. Correct the results obtained for the analytical determination.
3.5 Sampling and sample preparation
Depending on the size of the raw material, a sample of at least 1 kg up to 10 kg shall be taken by the procedure described in ISO 11464, dried, crushed, reduced and ground to form a representative laboratory sample for analysis. The laboratory sample shall pass a sieve of 90 pm mesh size conforming to ISO 3310-1. The drying process shall be modified, if necessary, to accommodate samples known to contain high contents of volatile organic carbon.
3.6 - - - - - 4 4.1 - - - - - - 4.2 4.3 4.4 4.5 4.6 4.7 4.8 3.6 General test principles
In general all procedures consist of the following stages:
- decarbonation of the original limestone sample;
- purification of the carrier gas, if it is not of high purified quality;
- oxidation of the organic carbon matter;
- purifying of the CO 2 produced by oxidation;
- measurement of the CO 2 content.
4.1 General requirements
Use only reagents of analytical quality. References to water mean distilled water, or water of equal purity. Unless otherwise stated percent means percent by mass.
The concentrated liquid reagents used in this standard have the following densities (p) in grams per cubic centimetre at 20 The degree of dilution is always given as a volumetric sum, for example: dilute hydrochloric acid 1 + 2 means that 1 volume of concentrated hydrochloric acid is to be mixed with 2 volumes of water.
4.2 Ammonia solution (NH 3 H 2 O)
4.3 Calcium chloride, anhydrous (CaCI 2 )
4.4 Calibration reagent. Metal, for example iron with known carbon content.
4.5 Carbon dioxide in oxygen, 0,95 vol.-% and 19 vol.-%
4.6 Carrier gases, depending on application: air, oxygen, nitrogen or argon, free of carbon dioxide and hydrocarbons
4.7 Chromic acid. 1 ) Dissolve 5 g of chromium trioxide (4.8) in 10 ml of water. Add sulfuric acid (4.13) with stirring, until the chromium trioxide, which initially precipitates, is just redissolved.
4.8 Chromium trioxide (CrO 3 )
4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 4.20 4.21 4.22 4.23 4.24 4.25 4.26 4.9 Concentrated hydrochloric acid ( 4.10 Concentrated hydrogen peroxide (H 2 O 2 )
4.11 Concentrated nitric acid (HNO 3 )
4.12 Concentrated phosphoric acid (H 3 PO 4 )
4.13 Concentrated sulfuric acid (H 2 SO 4 )
4.14 Copper (Cu), free of carbon
4.15 Copper oxide (CuO). Particle size of 0,6 mm to 1,2 mm
4.16 Dilute hydrochloric acid 1+5
4.17 Dilute nitric acid 1+9
4.18 Iron (Fe), free of carbon
4.19 Lead chromate (PbCrO 4 )
4.20 Magnesium perchlorate (Mg(CIO 4 ) 2 ), anhydrous. Particle size 0,6 mm to 1,2 mm.
4.21 Magnesium sulfate, anhydrous (MgSO 4 )
4.22 Magnesium turnings according to Grignard (Mg)
4.23 Manganese dioxide (MnO 2 ). Particle size of 0,6 mm to 1,2 mm.
4.24 Oxalic acid dihydrate (C 2 H 2 O 4 -2H 2 O)
4.25 Oxidation catalyst. Ignited silver permanganate with a composition of approximately AgMnO 4
4.26 Oxidizing mixture 1 ) To 85 ml sulfuric acid (4.13) in a 250 ml beaker add in order 15 ml phosphoric acid (4.12), 20 g phosphorus pentoxide (4.28), 15 g potassium dichromate (4.30), and 1 g potassium iodate (4.31). Carefully heat the mixture to about 170 4.27 4.28 4.29 4.30 4.31 4.32 4.33 4.34 4.35 4.36 4.37 4.38 5 5.1 5.2 4.27 Paraffin
4.28 Phosphorus pentoxide ( 4.29 Platinum (1 %) on alumina pellets (Pt). Particle size 3,2 mm, oxidation catalyst.
4.30 Potassium dichromate (K 2 Cr 2 O7)
4.31 Potassium iodate (KIO3)
4.32 Silver gauze (Ag). Wash commercially available silver gauze with ammonia solution (4.2), nitric acid 1+9 (4.17) and hydrogen peroxide (4.10). Rinse the gauze with water between each washing.
4.33 Sodium hydroxide (NaOH)
4.34 Sodium hydroxide (NaOH) on a high surface dark coloured siliceous carrier
4.35 Sodium hydroxide solution. Dissolve 40 g sodium hydroxide (4.33) in water and make up to 1 000 ml. Store in a polyethylene container.
4.36 Sodium iodide (Nai)
4.37 Sodium iodide solution. Add 10 ml of hydrochloric acid (4.9) and 150 g of sodium iodide (4.36) into a 1 1 volumetric flask and dilute to 1 I with water.
4.38 Zinc wool (Zn)
5.1 Balances capable of weighing to an accuracy of 5.2 Laboratory ovens capable of maintaining at the following temperatures: (75
6.1 Principle
The carbon dioxide in the limestone is driven off by use of phosphoric acid (4.12). The remaining organic carbon is then oxidized to carbon dioxide with a strong oxidizing reagent mixture (4.26). The liberated carbon dioxide is absorbed on an inorganic carrier impregnated with sodium hydroxide (4.34) in a U-tube. The increase in mass is directly proportional to the organic carbon content in the sample.
6.2 Apparatus
The apparatus is illustrated in Figure 1. To generate reduced pressure in the apparatus a small vacuum pump or an aspirator is used. The absorption tube (see Figure 1, no. 8) is filled approximately two thirds of its volume with the absorbent for carbon dioxide (4.34) and with magnesium perchlorate (4.20). The absorption tube is then inserted into the apparatus as shown in Figure 1 drawing through it about 4 I of carrier gas (4.6). At this time the apparatus should be checked for leaks by turning off the drying tower tap whilst keeping the small vacuum pump or the aspirator trap fully open. If leaks are absent the gas flow through the bubble counter stops completely. After checking for leaks, the taps of the absorption tube are to be closed, it is transferred to a desiccator for 10 min, weighed to an accuracy of 0,0005 g (m o1 ), and reassembled as shown in Figure 1.
The use of acid resistant fume cupboards and acid resistant gloves is obligatory.
6.3 Procedure
Weigh to an accuracy of 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Key:
1. Drying tower for carrier gas containing a carbon dioxide absorbent (4.34)
2. Safety trap
3. Inlet tube for the oxidizing mixture (4.26) with glass rod stopper
4. 150 ml round bottom distillation flask
5. 100 ml sharp botto