PROCESS FOR THE RECOVERY OF FORMALDEHYDE AND PHENOL CONTAINED IN WASTE WATERS

1377260 Treatment of waste waters SOCIETA ITALIANA RESINE SIR SPA 5 Dec 1972 [27 Dec 1971] 56153/72 Heading C1C [Also in Division C2] A process for the recovery of formaldehyde and phenol contained in waste waters comprises (i) supplying ammonia to the formaldehydecontaining waste waters at ambient temperature and with a mole ratio of formaldehyde to ammonia of approximately 1À5 : 1 such that hexamethylene tetramine is formed, (ii) evaporating the water from the aqueous solution of hexamethylene tetramine to total or partial dryness, i.e. a concentration of the tetramine of at least 64% by weight, (iii) adding the product of (ii) to the waste waters containing phenol so as to form an adduct between the hexamethylene tetramine and phenol at a temperature between that temperature at which the resulting adduct precipitates and 60‹ C. and at a mole ratio of hexamethylene tetramine to phenol of 0À5 : 1 to 3 : 1 and (iv) recovering said hexamethylene tetramine-phenol adduct. The adduct may be used as such, or broken down so that the phenol and formaldehyde may be recovered.