| abstract |
A process is provided for preparing ammonium glyphosate powder suitable for downstream processing by extrusion to make a granular formulation comprising ammonium glyphosate and surfactant. The process comprises (a) mixing (i) solid particulate glyphosate acid, (ii) water in an amount of about 0.5 to about 3 parts by weight per part by weight of glyphosate acid, and (iii) a base that supplies ammonium cations, in an amount of about 0.8 to about 1.25 mole equivalents of ammonia per mole of glyphosate acid, to form an aqueous reaction medium; (b) allowing the glyphosate acid to react with the base in the reaction medium to form a reaction product comprising a concentrated aqueous solution of ammonium glyphosate; (c) drying the reaction product, for example with a drum dryer, to recover a particulate solid; and (d) accelerating the particulate solid in a turbulent high-velocity gas stream, for example in a jet mill, to form by particle-particle attrition an ammonium glyphosate powder having a mean particle size of about 5 to about 20 νm. |