Sludge separation from e.g. metal- and semiconductor industries, employs chamber with circulating agitator and reduced pressure, to dry solids to powder and condense recovered liquid

摘要

Sludge separation apparatus for e.g. metal- and semiconductor industries, is new. The sludge is separated in a cylindrical recirculation chamber (4) with rotary agitation tools (8). It is heated to a given operating temperature under atmospheric pressure. The chamber is closed as recirculation continues. The pressure is reduced (14). Liquid components in vapor form, are extracted from the chamber and deposited in an external condenser (13). As the liquid content is reduced during processing, the recirculation tools cause grinding, working on the solids until they are turned to powder. The chamber is opened to remove it. In a particular instance, the sludge is a mixture of silicon- and silicon carbide particles which form the solid components, and oil or glycol as the liquid components. The mixed fraction is supplied to the centrifugation chamber following weeks of sedimentation, as a thickly-viscous mass, in sedimentation tanks. In another instance, the sludge is a mixture of oils, coolants, grinding materials with metal particles and metal dust. The pressure is reduced to about 100 mbar. The tools rotate at preferably less than 20 rpm. During processing, after chamber closure, the temperature drops. Later it is returned to the starting temperature or up to 30% above it.