GB1392462A - Process for reducing emission of dust by granular fertilizer compositions - Google Patents

Abstract

1392462 Reducing dust in fertilizer production ROYSTER CO 10 March 1972 11274/72 Heading C1B [Also in Division F4] In the manufacture of fertilizer compositions, wherein fertilizer particulates are heat-dried, size-classified and air-cooled, a process for rendering the fertilizer compositions resistant to emitting airborne dust upon attrition, comprises spraying the fertilizer particulates with an aqueous solution of a nitrogen-containing salt at the discharge end of the aircooler and at the end of the air-cooling phase of the manufacturing procedure. The aqueous solution spray of the invention bonds the fine, dust-like fertilizer particles in the cooled product stream to one another and to relatively larger particles and thus serves to agglomerate fertilizer dust particles with the formation, in turn, of agglomerates have increased density, greater projected surface area, or both. The conventional cooling devices ordinarily used to cool granular fertilizer products include: fluidized bed or semi-fluidized bed coolers, tray coolers, and rotary drum coolers, the latter being the most widely used type. Specified aqueous solutions are those containing ammonium orthophosphate, ammonium polyphosphate, calcium nitrate, ammonium nitrate, urea, urea phosphate, urea nitrate and mixtures thereof. The fertilizers may be ammoniated phosphoric acid or various N: P: K products.