Centrifuging and washing crystal suspensions - in successive stages, with wash liquor added in stages between centrifuging

摘要

For purification of crystals for mfr. of highly pure (in) organic cpds. pref. the sepd. wash liquor is fed back in the intermediate stages and is fed stepwise in countercurrent to the solids. The appts. has a sieve basket and screw, both rotatable, driven independently of each other, with a small gap between, with the screw within the drum, and both in a closed housing, which is divided into sections at 90 degrees to the rotation axis, forming chambers with the respective basket walls, each of which has an impermeable region at the prodt. entry side; each chamber has a drain. The screw has a liquor inlet at the prodt. inlet side of the second and further sections, and stirrers project into the screw path on the entry side.