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BS ISO 334:2013 pdf free

BS ISO 334:2013 pdf free.Solid mineral fuels – Determination of total sulfur – Eschka method
Place a watch glass on the beaker and then, while tilting the watch glass, carefully add enough hydrochloric acid (4.2) 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 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.
Add two or three drops of the methyl red indicator solution (4.5) to the combined filtrate and washings,and then cautiously add the ammonia solution (4.6) until the colour of the indicator changes and a trace of precipitate is formed. Add enough hydrochloric acid (4.2) to just redissolve the precipitate and then add 1 ml in excess.
After extraction, dilute the solution, if necessary, to approximately 200 ml and cover the beaker containing the solution with a watch glass. Heat the covered beaker until the solution boils and then reduce the heating slightly until ebullition of the solution ceases. Then add 10 ml of the cold barium chloride solution (4.4) from a pipette with a delivery time of approximately 20 s so that the barium chloride solution falls into the centre of the hot solution while it is being agitated. Keep the solution just below boiling point for 30 min.BS ISO 334 pdf download.

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