Purifcn. of effluents contg. phenol and formaldehyde - by pptn. with aminoplast pre-condensate under alkaline conditions at boiling temp.

摘要

Purification of effluents contg. phenol or its derivs. and formaldehyde and their addition or condensation products by conversion of these substances into insoluble form, is improved by adding to the effluents water-soluble pre-condensates of aminoplasts in an amount of 30-125 g. per g. -equiv. of the phenolic OH gps.; adjusting the pH of the effluent to 9-10 using an alkali; heating at the boiling temp. for 2-8 hrs. with stirring; adjusting the pH to 6-7; sepg. the precipitated matter; and transferring the effluents to a classification plant. Effluent water from the prodn. of formaldehyde resin, contg. large amts. of dissolving phenol and formaldehyde contaminants can be effectively purified and valuable substances can be recovered; they are of the Duroplast type and can be utilised as such, or just burnt.