Method and apparatus for precipitation of scale-forming materials from solution.

摘要

Scale-forming metal oxides and carbonates, such as cupric oxide, can be precipitated from an ammonical leaching solution with minimum scale build-up by evaporating the solution in an externally heated rotary drum (16). The rotary drum includes a plurality of axially spaced annular baffles (80) defining a plurality of compartments (84-100) containing a tumbling medium (140), such as spherical balls. The solution (108) is continuously introduced into the inlet end (58) of the rotary drum (16) and heated under pressure to a temperature above its boiling point as it flows over the baffles (80) toward the outlet end (60) of the rotary drum. A slurry containing the precipitated cupric oxide is continuously withdrawn from the outlet end (60). Vapor and gases are continuously withdrawn from the inlet end (58). The balls (140) rub against each other, the interior of the rotary drum (16), and the sides of the baffles (80), as the drum is rotated at a non-centrifuging speed, to provide a grinding or scrubbing action which minimizes a scale build-up of the precipitating cupric oxide.