Praestol 857 BS Praestol 859 BS can be replaced by Chinafloc C8008
Praestol 857 BS and Praestol 859 BS are two cationic flocculant with very high charge and molecular weight.
This product is primarily used for dewatering of municipal and industrial sewage sludge (centrifuges, filter belt presses, chamber filter presses, etc.). It is specially suitable for applications where the formed flocs are subjected to high shearing forces.
The product is normally used as a highly diluted solution (0.2 to 0.5 %). For preparation of stock solutions (approx. 1.0 %) the original product is added to water while stirring. After a dissolving period of approx. 15 minutes (at a temperature of approx. 20 °C) the solution is mature and thus ready for use. Due to the varying properties of the sludge to be dewatered, the required dosages for a particular application can only be determined for a particular application by carrying out laboratory tests or industrial trials. The polymer consumption generally varies between approx. 3 and 10 kg polymer active substance per ton of sludge dry solids. In applications such as thickening or secondary sedimentation low values are found. Sludge which is difficult to dewater require significantly more polymer.
Products in emulsion form are basically sensitive to moisture, such as condensation and splashes. Contact with water (droplets) can lead to local formation of knots and lumps. The product should therefore be stored in dry, closed containers, protected against moisture. Even in closed containers or drums it is not possible to completely prevent condensation. Some lumps may occur due to this condensation, but in general these will redissolve if agitated mechanically (e.g. recirculation by pumping) and the quality of the product is not affected. After prolonged storage the product might tend to separate into layers. After homogenization by intensive stirring, pumping or re-circulation by gas injection (nitrogen, air) the product may be re-used without any loss in quality. The storage temperature should not exceed 40 °C for long periods. Water contaminating class: 2 (self classification)
Storage Stability under Correct Storage Conditions Product in original packing: at least 12 months Stock solution in tap water*: at least 1 week Ready-to-use solution in tap water*: at least 1 day