Rotatable salt cake evaporator drum with internal fins - which dip into brine to form slurry for salt recovery

摘要

An evaporator system for recovering crystalline salt from heavy brine comprises an elongate drum which is inclined upwardly towards an output end and has fins mounted on the drum interior which make an angle of 5-85 degrees with the radius of the drum. The fins at the input end extend a smaller distance from the drum wall than those fins at the output end. The drum is rotated to cause the fins to dip into a body of brine in the drum. A stream of gas is simultaneously forced through the drum. An annular well is formed at the outlet end to provide a sump for the removal of brine from the drum. Used for treatment of salt cake resulting from the recovery of metal values in dross from Al refining. Evapn. occurs without the necessity of the liquid reaching b.pt. The rotation of the fins causes a disturbance of the liquid surface and increases the rate of evapn. The evaporator is self-cleaning with no build-up of salt on the evaporator surfaces. Al and aluminium oxide can be recovered with great efficiency.