Sealing of porous articles with curable impregnating fluid

摘要

Process for sealing porous articles, esp. metal castings or sintered metal parts, comprises impregnating the articles with a cold- or heat-curable impregnating fluid contg. water soluble components, rinsing the articles with an aq. wash liq. to remove adherent impregnating fluid, and curing the articles. The spent wash liq. is passed to a single or multi-stage reverse osmosis unit to obtain a retentate contg. most of the impregnating fluid components and an aq. permeate that is largely free of these components. The permeate is passed to a waste water disposal system or is used as wash liq. The retentate is disposed of or processed to recover organic components for prodn. of the impregnating fluid.