Values and water recovery from aq. process liq. - by membrane distillation giving recyclable concentrate and distillate usuable instead of deionised water

摘要

Recovery of values and water from aq. process liqs., esp. from electroplating and electroless plating plants, anodising and conversion coating plants, pickling baths, polishing baths, residual refining electrolytes, ion exchanger regenerates and rinsing baths, is carried out by (i) contacting the liq. with a liq.-tight, vapour permeable, microporous membrane which is not wetted by the liq.: and (ii) allowing water vapour and other opt. present volatile matter to pass as gases through the micropores to the other side of the membrane for condensation at reduced temp. ADVANTAGE - The process produces a concentrate, which can be recycled to the treatment process, and a distillate, which can be used instead of deionised water e.g. in a final rinsing operation or in prepn. of new baths. The membrane distillation process has good sepn. properties, simple operation and low temp. and employs inexpensive and compact appts.