BS ISO 334:2020 pdf download – Coal and coke — Determination of total sulfur — Eschka method 8.3 Ignition 8.3.1 For coal Place the charged crucible (and any others up to the limit of the muffle furnace capacity) in the cold muffle furnace (6.3) and raise the temperature to 800 °C ± 25 °C in about 1 h, maintaining this temperature for at least a further 1,5 h. Withdraw the crucible (or crucibles) and allow to cool. NOTE The cracking of porcelain crucibles can be prevented if they are slowly cooled by insertion in supports of light porous firebrick on removal from the muffle furnace. 8.3.2 For coke Place the charged crucible (or crucibles) on the cold insulating flat plate (6.5) and insert into the muffle furnace (6.3) at a temperature of 800 °C ± 25 °C, maintaining this temperature for at least a further 1,5 h. Withdraw the crucible (or crucibles) and allow to cool. See Note in 8.3.1. 8.4 Recovering the residue Transfer the ignited mixture from the crucible to a 400 ml beaker containing 25 ml to 30 ml of water. If unburnt particles are present, the determination shall be stopped and the test repeated. Wash the crucible thoroughly with about 50 ml of hot water and add the washings to the contents of the beaker. 8.5 Extraction Place a watch glass on the beaker and then, while tilting the watch glass, carefully add enough hydrochloric acid (5.2) to dissolve the solid matter (17 ml will normally be required), warming the contents of the beaker to effect solution. Boil for 5 min to expel carbon dioxide and filter, collecting the filtrate in a 400 ml conical beaker. NOTE A medium-textured, doubly acid-washed filter paper or a filter-paper pad is recommended for speed of filtration. To prepare the filter-paper pad, shake doubly acid-washed filter-paper clippings, in pieces with areas of approximately 1 cm 2 , with water in a bottle until the paper is thoroughly disintegrated. Place a porcelain filter cone of 25 mm in a 75 mm funnel, close the stem of the funnel with a finger, and add water until the cone is immersed and the funnel stem is full. Shake, onto the cone, sufficient paper pulp to form a pad 5 mm thick, and level it with a flat-ended glass rod. Allow the excess water to drain away by removing the finger from the stem...
Download Address
Download