Patent ID: 7179435

Claim:
Apparatus for the purification of a substance from a solution, a suspension or a mixture of liquids by crystallization, comprising: a. a first crystallizer ( 1 c ) comprising an input ( 1 ) for receiving a liquid comprising the substance and an output ( 4 ) for discharging a slurry of liquid and crystals, b. a first separator ( 1 s ) connected to the output ( 4 ) of the first crystallizer ( 1 c ) having a product output ( 2 ), and having a residue output ( 5 ) connected to an input of a second crystallizer ( 2 c ), c. a second separator ( 2 s ) having an input connected to an output ( 6 ) of the second crystallizer ( 2 c ) and having a crystal output ( 7 ) connected to an input of the first crystallizer ( 1 c ), wherein crystals separated in the second separator ( 2 s ) are combined with a slurry stream ( 11 ) from the first crystallizer that bypasses the first separator and the second crystallizer before being input into the first crystallizer ( 1 c ).