BS EN 12879:2000 Determination of the loss on ignition of dry mass
5 Interferences There are nomally no interferences with the loss on igition determination, However, for many purposes this determination is used as an assessment of the organic part of the sludge dry mass. In this case the loss of volatile inorganic substances can occur giving high results.
NOTE 1 AII sewage sludges contain iron in varping qua niies and most of it will be present a frrours ion. ,During ignition iron叫wil be axidized to iron叫) with a possible incnease in mass and therefore a meduction in the loss on igniton.
NOTE2 It a sludge has been condtboned wth Ime. the calclum hnydroxide or calclum oide present wll be allable to combine with sulfur axides liberated during ignilion or with carbon dioxide formed during ignition decresing the loss on ignition value.
6 Hazards
6.1 General Samples are liable to ferment and usually contain harmful micro-organisms. It is esental to keep them away from any food or drink, and t如o prolect any culs, Bursting glass botles containing sludge can produce micro-organism contaminated shrapnel. Plastic bottles can also burst and produce a hazardous spray and Berosol.
6.2 Storage It is advisable not to store samples in the open laboratory. If samples are to be stored, store them between 0°C and4 °C.
6.3 Handling Cleanliness when working is essential. When handing sludge samples, it is necessary to wear gloves, face and eye protection, and sficient body protection to guard against botlee bursting. The gas evolwved is usually fla mmable, s0 all equlpment used in the vichnity must be flame prool to avold any source of inition.
7 Apparatus
7.1 Crucible. (50 to 70) mm in diameter, suitable for initon at 550 °C, eg. porcelain, silica or platinum.
7.2 Muffle fumace or quialent equipment, apable of maintaining a temperature of (550土25) °C 7.3 Desiccator, with a active drying agent. such as sliai gel or diphosphorus pentoxide.
7.4 Analytical balance. wilth a accuracy of 1 mg or blter. 8 Procedure If the determination of loss on ignitin is crried out in the same crucible 8s the determination of dry rsidue, refer to EN 12880 for the initial crucible weighing. If not, the sample is a representative portion of the dry mass obtained ccording to EN 12880. All the necessary precautions shall be taken to avold absoption of atmospheric humidily by the sample until it is weighed. Place a crucible (7.1) in the furmace (7.2) and heat at (550土 25) “C for at least 30 min. Ater coolng in the desiccator (7 .3) to ambient temperalure, weigh to the nearest 1 mg.
BS EN 12879:2000 Determination of the loss on ignition of dry mass