BS ISO 5071-1:2021 pdf download – Brown coals and lignites — Determination of the volatile matter in the analysis sample Part 1: Two-furnace method
This document specifies a method of determining the volatile matter of brown coals and lignites.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1170, Coal and coke — Calculation of analyses to different bases
ISO 1213-2, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and analysis ISO 5068-2, Brown coals and lignites — Determination of moisture content — Part 2: Indirect gravimetric
method for moisture in the analysis sample
ISO 13909-4, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples
ISO 18283, Coal and coke — Manual sampling
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1213-2 apply.
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The coal is heated out of contact with air for 7 min at 400 °C, then immediately transferred to another furnace and heated at 900 °C for a further 7 min. The volatile matter mass fraction is calculated from the loss in mass of the oven-dried sample or from the loss in mass of the analysis sample corrected for moisture.
5.1 Desiccants, fresh or freshly regenerated and preferably self-indicating. Suitable desiccants are magnesium perchlorate, silica gel, activated alumina and anhydrous calcium sulfate.
WARNING — Magnesium perchlorate is a strong oxidizing agent. Do not attempt to regenerate the absorbent. Do not permit contact with organic materials or reducing agent.
The sample shall be the general analysis test sample, prepared to a nominal top size of 212 μm by the preparation procedures specified in ISO 13909-4 or ISO 18283.
The sample should be brought in moisture equilibrium with the laboratory atmosphere by exposure in a thin layer on a tray. Exposure time shall be kept to a minimum. The sample shall be thoroughly mixed immediately before analysis, preferably by mechanical means.
Duplicate determinations of moisture from the same test sample shall be conducted concurrently with the determination of volatile matter by the method specified in ISO 5068-2. 8 Procedure
8.1 Preliminary procedure Adjust the temperature of the zone in the furnaces (6.1), loaded with a stand and empty crucibles where appropriate, to 400 °C ± 10 °C and 900 °C ± 5 °C respectively, as indicated by the correctly unsheathed thermocouple (6.3). Remove the stand and crucibles and close the doors of the furnace. Heat, in a furnace (6.1) at 900 °C for 7 min, either one crucible and lid (6.4) or the requisite number of crucibles and lids to fill the multiple stand. Remove the crucible(s) from the furnace and cool them, first on a metal slab and finally in a desiccator (6.7) located next to the balance. As soon as it is cool to ambient temperature, determine the mass of each empty crucible and lid. Record the mass(es) of the preconditioned crucibles and lids to the nearest 0,1 mg (8.4, Note 1).
8.2 Predetermination procedure Accurately transfer a 1,00 g to 1,01 g mass of sample (see Clause 7) to the nearest 0,1 mg into each preconditioned crucible. Replace the lid and tap the crucible on a clean hard surface until the sample forms a layer of even thickness on the bottom of the crucible. Proceed in accordance with either 8.3 or 8.4 depending on whether or not the coal has been oven-dried or air-dried.
8.3 Method using oven-dried coal
Place the charged crucible(s), with lid(s) removed, in the oven (6.2) at 105 °C to 110 °C. Dry the sample(s) to constant mass in accordance with the procedure for moisture determination specified in ISO 5068-2. Record the mass(es) of the oven-dried crucible(s), lid(s) and sample(s) to the nearest 0,1 mg.
Place the crucible(s) fitted with lid(s) containing the oven-dried sample(s) in a suitable stand (8.4, NOTE 2) and transfer to the furnace set at 400 °C for 7 min. Immediately transfer to the furnace set at 900 °C for a further 7 min. A temperature of 400 °C ± 10 °C or 900 °C ± 10 °C is regained within 4 min after insertion of a cold stand and its crucibles.BS ISO 5071-1 pdf download.