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BS ISO 17992:2013 pdf free

BS ISO 17992:2013 pdf free.Iron ores – Determination of arsenic content
Transfer the test portion to a 250 ml beaker. Moisten with a few millilitres of water, and add 30 ml of hydrochloric acid (4.7) and 1 ml of nitric acid (4.8). Cover with a watch- glass and heat gently until most of the test portion is decomposed. Increase the heat and digest just below boiling, until no further attack is apparent. Evaporate the solution to near-dryness, cool, add 10 ml hydrochloric acid (4.9), and dissolve salt. Transfer the solution obtained to a 100 ml volumetric flask, dilute to the mark with water, and mix.
If a residue is found in the solution, it should be treated by filtering the solution through a medium-texture filter paper into a 250 ml beaker. Carefully remove all adhering particles with a rubber-tipped glass rod and transfer to the filter, washing three times with dilute hydrochloric acid (4.10), then with hot water until the paper is free of iron. Transfer the paper and residue to a zirconium crucible. Retain the filtrate. Dry and ash the filter paper and residue at a low temperature. Add the mixture of 0,2 g sodium peroxide (4.1) and 0,4 g sodium carbonate (4.2) to the residue, heating gently, then igniteit in a muffle furnace at 700 °C for 10 min. Cool, dissolve the cooled melt with 5 ml of hydrochloric acid (4.10),and transfer into the retained filtrate.
The test portion should be taken and weighed quickly to avoid re-absorption of moisture. During evaporation, the watch glass can be moved a little.
Transfer an appropriate aliquot of this solution (see Table 1) or certified reference material solution to a 100 ml one-mark volumetric flask, add adequate volumes of background solution (4.16) so that the contents of the iron in the test solution are matched to 1,5 mg/ml, then add 10 ml of ascorbic acid solution (4.15), 10 ml of potassium iodide solution (4.14), and hydrochloric acid (4.11) to the mark and mix. Stand the solutions for 3 h, then use for determination. Carry out determination of the blank test portion at the same time.BS ISO 17992 pdf download.

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