Further, the relatively low temperature impedes decarburization.
Nevertheless, it has been found in practice, when syrups with low quotient of purity and high quotient of impurity are being treated, injecting the feed at a number of different points in the pan does reduce the time required to boil the pan, though of no practical advantage with syrups of high quotient of purity and free from the viscosity which impedes circulation and therefore quick boiling.
Such a slag not only corrodes the furnace lining, but also impedes dephosphorization, because it is irretentive of phosphorus.
Sometimes, to get rid of these impurities, the brine is treated in a large tub-`(bessoir) with lime; on settling it becomes clear and colourless, but the dissolved lime forms a skin on its surface in the pan, retards the evaporation and impedes the crystallization.
The flatness impedes drainage which results in the compost staying too wet.
