During the production of electrodes, binder pitch is added to a dry aggregate recipe to form green blocks that are then baked. During baking, the binder pitch is converted to pitch coke; the aim being to retain as much carbon as possible in the electrode to ensure a high density level.
The coking value is one of the key properties to qualify a pitch. It corresponds to the measurement of the residual carbon from the pitch after its cokefaction.
The measurement is conducted with the RDC-178 apparatus, where a pitch sample will be heated up to 550°C under controlled conditions in a crucible, to remove its volatile compounds. The residual material during this cokefaction process is used for the calculation of the coking value and expressed as a percentage of the initial sample weight.
Weighing scale with an accuracy of 0.0001 g
Crusher (< 4 mm)
Desiccator
Sieving machine (0.25 mm sieve)