Societa' Italiana Resine S.i.r. S.p.a.

Umberto Santini

Pierino Radici

Paolo Colombo

Jacob Ackermann

Pietro Erini

Formaldehyde present in a waste water containing lower carboxylic acids is recovered by reacting said waste water at 0.degree. to 90.degree. C. with the amount of ammonia required for converting said formaldehyde into hexamine and the latter is recovered in solid form by evaporating the resulting solution. The solid hexamine thus recovered has a content in lower carboxylic acids not exceeding 0.05 wt.%, is practically free from other impurities and is suited for any conventional use.

Process for the recovery of formaldehyde present in waste waters

Process for the separation of trioxane from aqueous solutions containing it together with formaldehyde, which comprises subjecting the said solutions to evaporation at temperatures of 100.degree. C or lower, at pressures lower than atmospheric, and with residence times of less than 1 minute under the evaporation conditions, with vaporization of a quantity of from about 5 to about 15% by weight of the solution introduced, and recovering the trioxane from the products evaporated in this way.

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Legnano (Milan), Italy

Umberto Santini