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1． Method summary: Weigh a certain amount of air-dried coal sample, place it in a covered porcelain crucible, and heat it for 7 minutes without air at a temperature of 900±10°C. The volatile matter yield is calculated as the percentage of reduced mass in the mass of the coal sample, minus the moisture content of the coal sample. 2． Instruments and Equipment ① Volatile crucible: Porcelain crucible with a tight-fitting lid. ②Muffle furnace ③ Crucible holder ④ Crucible holder clamp ⑤ Analytical balance: Sensitivity: 0.0001g. ⑥Stopwatch⑦Dryer: Color-changing silicone inside 3. Analysis steps ① Use a covered porcelain crucible that has been preheated at 900°C until the mass is constant. Weigh 1±0.01g of air-dried coal sample with a particle size of less than 0.2mm, accurate to 0.0002g, then gently shake the crucible to flatten the coal sample, cover it, and place it on the crucible. ②Preheat the muffle furnace to about 920°C. Open the furnace door, quickly move the rack with the crucible into the constant temperature zone, close the furnace door, and heat for exactly 7 minutes. Just after the crucible and rack are put in, the furnace temperature will gradually drop, but the furnace temperature must be restored to 900±10℃ within 3 minutes, otherwise the test will be invalid. Heating time includes temperature recovery time. ③Take out the crucible from the furnace, let it cool in the air for about 5 minutes, move it to a desiccator and cool it to room temperature (about 20 minutes), then weigh it. 4. Analysis results are calculated. The volatile matter of air-dried coal samples is calculated according to the following formula:: Vad=m1/m * 100-Mad Vad—volatile yield of air-dried coal sample (%) m1—mass reduction of coal sample after heating (g) m—mass of coal sample (%) Mad—moisture content of air-dried coal sample (%) 5. Precision of volatile matter determination Repeatability and reproducibility of volatile matter determination are specified in the following table: Volatile repeatability Vad Reproducibility Vd 40 0.80 1.50 This post was last edited by ryn on 2009-2-18 14:31 ]