BS EN 15935 pdf free download

BS EN 15935-2021 pdf free download.Soil, waste, treated biowaste and sludge – Determination of loss on ignition.
5 Interferences and sources of errors
LOl is an empirical parameter, thus in principle there is no interference connected to the determination. However, for some purposes the determination ofLOl is used forthe assessment ofthe content of organic matter in the sample. It should be noted that elemental carbon in the sample will be included in the loss on ignition value. Furthermore, any volatilisation or chemical reactions ofinorganic compounds will also be included in the loss on ignition value.
Chemically bound water could be released during heating, thereby contributing to the loss on ignition.
Samples containing iron or other metals in low bonding state or in metallic state can be oxidized during heating, thereby contributing to the loss on ignition with a negative amount.
Suiphides present in the sample could be oxidized to sulphate during heating, thereby contributing to the loss on ignition with a negative amount.
Explosive ignition is likely to result in loss of residue from the crucible, thereby contributing to the loss on ignition with a positive amount. If such loss of residue is observed during the removal of the crucible from the furnace, the test shall be discharged and repeated taken the necessary precautions, e.g. using a smaller test portion.
Calcium hydroxide or calcium oxide present in large amounts (e.g. sludge conditioned with lime) can combine with sulphuric oxides liberated during ignition or with carbon dioxide formed during ignition resulting in a too low content of the loss on ignition. Such reactions can be avoided using the stepwise heating procedure stated in 7.4 combined with a sufficient ventilation rate in the furnace and a height of the sample layer in the crucible not exceeding 5 mm.
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 Furnace, 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 scale, with an accuracy ofat least 1 mg.
7 Procedure
7.1 Preservation
Preserve samples according to e.g. EN ISO 5667-15 or ISO 18512, as appropriate.
For biological inactive samples special preservation may not be necessary. Biological active samples should be made inactive e.g. by freezing or air-drying.
7.2 Pretreatment
Pretreat samples according to e.g. EN 15002 or EN 16179, as appropriate.
Depending of the origin, nature and appearance of the sample different procedures stated in e.g.
EN 15002 or EN 16179 can be used:
a) Solid waste samples to be comminute and reduced to a granular powder, preferably a particle size less than 200 im. If no volatile substances are present in the sample, sample may be air-dried prior to comminuting. The drying temperature ofthe air-drying shall not exceed 40 °C.
b) Moist or pasty-like waste samples may be mixed with aluminium oxide until a granular material is obtained and then comminuted, preferably to a particle size less than 200 pm. In this case the ratio ofaluminium to sample shall be considered in the calculation ofthe loss on ignition.
c) Liquid samples shall be homogenized immediately prior to the weighing ofthe test portion.
Foreign bodies or non comminutable material (as metallic parts such as nuts, blots, scrap) should be separated from the sample and the weight and nature ofthe material recorded.
7.3 Determination
The determination ofloss on ignition can be performed using
— an undried sample (see 7.4);
— an air-dried sample;
— a sample after determination of dry matter at (105 ± 5) °C, in successive operations using the same crucible.
The dry matter is determined according to EN 15934.
NOTE This procedure can be combined with the determined according to EN 15934 by using a crucible (6.1)
dried at (105 ± 5) °C.
Place a crucible (6.1) in the furnace (6.2) and heat to (550 ± 25) °C and hold for at least 20 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 scale (6.5) to the nearest 1 mg.
Weigh into the crucible a test portion of 0,5 g to 5 g of the test sample to the nearest 1 mg, and place the crucible into the furnace. Larger masses may be taken if complete combustion can be ensured.
Raise the furnace temperature to (550 ± 25) °C 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 1 mg.
if black carbon particles are still present (some organic substances burn slowly at 550 °C), 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 for at least 1 h.
NOTE Ammonium nitrate solution is prepared by dissolving 10 g of reagent grade ammonium nitrate, NH4NO3, in 100 ml distilled or demineralized water.
The mass after at least 2 h heating at (550 ± 25) °C is considered constant.
7.4 Samples containing a high content of volatile or organic substances or undried samples
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 on the undried sample.BS EN 15935 pdf download.