ISO 20336-2017 pdf download.Solid mineral fuels一Determination of total sulfur by Coulomb titration method.
5.4 Self-indicatIng silica gel, industrial grade.
5.5 Sodium hydroxide, chemical grade.
5.6 Electrolytic solution.
5 g of potassium iodide (51) and 5 g of potassium bromide (52) are dissolved in (250 to 300) ml of water, then add 10 ml of glacial acetic acid.
5.7 Glass wool.
5.8 Alurninosilicate wool.
5.9 Catalyst, tungsten trioxide.
5.10 Certified reference materials (CRM5), coal or coke.
6 Apparatus
6.1 Instrument.
For determining sulfur by Coulomb titration, commercially available, consisting of the following (see FiguizeI).
6.2 Tube resistance furnace and combustion tube.
Capable of maintaining a temperature 01(1 150 ± 10) °C in the combustion zone which is at least 70 mm long, with the Pt-Rh—-Pt thermocouple and the temperature controller. Combustion tube is made of silicon or corundum, capable of withstanding temperatures greater than 1 300 °C.
6.3 Electrolytic cell and magnetic stirrer.
Electrolytic cell consists of a cylindrical glass cup of over 400 ml capacity, with (120 to 180) mm high, in which there are a pair of Pt electrolytic electrodes each of 150 mm2 area and a pair of Pt indicating electrodes each of 15 mm2 area. The response time of indicating electrodes should be less than I s. The magnetic stirrer with speed of 500 r/min and regulator is also provided.
6.4 Coulomb integrator.
The integration linearity error is less than 0,1 % at (0 to 350) mA of electrolyzing current, with a (4 to 6) digital display or printer to give the content of the sulfur in the sample.
6.5 Program controller.
The sample can be pushed into and withdrawn from the combustion tube according to the specified
program.
6.6 Purified air stream supply system.
Consists of the magnetic pumps and purifying tubes. Supply an air stream at the rate of 1 500 mI/mm and draw it at 1 000 mI/mm, which is purified and dried by the sodium hydroxide and self-indicating silica gel packed in the purifying tubes respectively.
NOTE The sodium hydroxide is not necessary for the laboratories in which the air is not polluted by acid gas.ISO 20336 pdf download.