BS ISO 334:2020 pdf free.Coal and coke一Determination of  total sulfur- Eschka method.
BS ISO 334 Cover the bottom of the crucible (6.4) uniformly with 0,5 g of the Eschka mixture (5.1), weighed to the nearest 0,1 mg. Mix the test portion intimately with 2,5 g of the Eschka mixture, weighed to the nearest 0,1 mg, in a suitable vessel. Transfer the mixture to the 25 ml crucible. Level the contents by tapping the crucible gently on the bench and cover the contents uniformly with 1,0 g of the Eschka mixture,weighed to the nearest 0,1 mg.The entire 4 g of the Eschka mixture should be weighed out and the 0,5 g and 1 g portions, required for the bottom and top layers, should be extracted from this. For this purpose, it is convenient to calibrate a small glass tube for each bath of the Eschka mixture to deliver 0,5 g and 1 g without weighing. The bottom layer of the Eschka mixture below the test portion mixture reduces attack on the porcelain surface so that the extraction of sulfate with hot water is complete even when the surface deteriorates.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.To prepare the filter-paper pad, shake doubly acid-washed filter-paper clippings, in pieces with areas
of approximately 1 cm2, 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 and as drainage ceases, lightly tamp the pad around the edges with the glass rod. A final wash with water renders the filter ready for use.Wash the filter with five 20 ml portions of hot water.BS ISO 334 pdf download.