BS EN 15935-2012 pdf download.Sludge , treated biowaste , soil and waste – Determination of loss on ignition.
6 Apparatus
6.1 Crucible, preferably flat bottom type and typically 50 mm to 70 mm in diameter, suitable for ignition at
550 C. e.g. made of nickel, platinum, porcelain, or silica.
6.2 Muffle furnace, or equivalent equipment, capable of maintaining a temperature of (550 ± 25) C.
6.3 Metal plate, or comparable plate, suitable for the initial cooling of crucibles.
6.4 Desiccator, with an active drying agent, such as silica gel.
6.5 PrecIsion balance, with an accuracy of at least 1 mg.
7 Procedure
7.1 Samples with low content of volatiles
If the determination of dry matter fraction and the determination of loss on ignition are carned out in successive operations in the same crucible refer to EN 15934 for the initial crucible weighing. If the determinations are performed as separate operations, representative portions of the sample shall be used for the determination of loss on ignition and dry matter fraction according to EN 15934. Alternatively the sample material may be dried according to EN 15934 before the determination of the loss on ignition. Every necessary precaution shall be taken to avoid absorption of atmospheric humidity by the sample until weighed.
Place a crucible (6.1) in the furnace (6.2) and heat to (550 ± 25) C for at least 30 mm. Transfer the crucible from the furnace after initial cooling on a metal plate (6.3) to a desiccator (GA) and finish cooling to ambient temperature. Weigh the empty crucible using a precision balance (6.5) to the nearest 1 mg.
Weigh into the crucible 0.5 g to 5 g of the test portion to the nearest 1 mg. and place the crucible into the furnace. Raise the furnace temperature to (550 ± 25) °C and hold this temperature for at least 2 h. The sample layer in the crucible should not exceed a height of 5 mm.
If the test portion has high organic matter content, losses may occur as a result of rapid ignition or deflagration of the sample. In this case heat the sample slowly until ignition. For certain wastes (e.g. paper wastes and demolition wood) a step-wise heating process can be used: the crucible is inserted in a cold furnace: the temperature is raised slowly to 250 °C over a period of 50 mm, allowing pyrolysis of the sample. Then the temperature is raised slowly to 550 DC and the 550 °C is kept for at least 2 h.
If the sample contains higher amounts of moisture, insert the crucible in a cold furnace and raise the furnace temperature evenly to (550± 25) C over a period of 1 h and hold this temperature for at least 2 h.
Place the hot crucible containing the residue on ignition on a metal plate (6.3) for a few minutes. While still warm, transfer the crucible to a desiccator (6.4) and leave to cool to ambient temperature.
As soon as ambient temperature is reached, weigh the crucible containing the ignition residue to the nearest 1mg.
If black carbon particles are still present (some organic substances bum slowly at 550 CC). moisten the residue using a few drops of an ammonium nitrate solution. Insert the crucible into the furnace and slowly heat to avoid losses by the steam development and continue heating the residue at (550 ± 25) °C. Ammonium nitrate solution is prepared by dissolving 10 g of reagent grade ammonium nitrate, NH4NO3, in 100 ml distilled water
7.2 Samples containing volatile substances
For samples containing significant amounts of volatile substances the dry matter cannot be determined as dry residue. In this case the dry matter shall be calculated from the water content according to EN 15934 method B, and the loss on ignition is always performed directly on the undned sample.
Place a crucible (6.1) in the furnace (6.2) and heat at (550± 25) C for at least 30 mm. Transfer the crucible from the furnace after initial cooling on a metal plate (6.3) to a desiccator (6.4) and finish cooling to ambient temperature. Weigh the empty crucible using a precision balance (6.5) to the nearest 1 mg.
Weigh into the crucible 0,5 g to 5 g of the test portion to the nearest 1 mg. Larger masses may be taken if complete combustion can be assured. All necessary precautions should be taken to avoid loss of volatiles from the samples until it has been weighed.
To avoid splashing caused by escaping vapours or sudden fire, most of the volatile components should be removed from the sample at ambient temperature in a fume hood prior to ignition.
Samples containing highly flammable components e.g. solvents or waste oil should be ignited and allowed to bum in a fume hood before being inserted into the furnace.
When ready place the crucible into the cold furnace, Raise the furnace temperature to (550 r 25) °C and hold this temperature for at least 1 h.
Place the hot crucible containing the residue on ignition on a metal plate (6.3) for a few minutes. While still warm, transfer the crucible to a desiccator (6.4) and leave to cool to ambient temperature.
As soon as ambient temperature is reached, weigh the crucible containing the ignition residue to the nearest 1 mg.BS EN 15935-2012 pdf download.