GB1047913A - Process for manufacturing a urea-formaldehyde fertilizer - Google Patents

Abstract

A urea formaldehyde fertilizer is prepared by subjecting one molar proportion of urea to partial condensation with from 3-6 molar proportions of HCHO under alkaline conditions whilst the reacting mixture is simultaneously evaporated to give a concentrate containing more than 50% by weight of solids, mixing urea with the concentrate to provide the urea to HCHO molar ratio desired in the fertilizer, further condensing the mixture by the addition of acid and subsequently terminating the condensation rapidly by the addition of alkali, e.g. NaOH. The product may be granulated and thereafter dried. The initial condensation may be performed with 4-5 mols of HCHO per mol of urea. The further condensation of the urea formaldehyde solution after acidification may be effected in an evaporator provided with a feed screw into which evaporator the alkali is fed to neutralize and interrupt the reaction after the desired degree of condensation has been obtained. Alternatively the further condensation may be effected on a conveyer, from which the mixture is passed to a kneader together with the alkali. The final product may be granulated.