Precision granulation

A process for granulation of a particulate material by subjecting the particles to a repeated circulating movement comprising an upward pneumatical movement from a starting area inside a vertical granulation pipe while the particles are entrained in a stream of drying and moving gas and simultaneously being subjected to a spray of droplets of granulation liquid, said circulating movement further comprising a downward movement outside said pipe, and a horizontal movement towards the starting area for said pneumatical movement, characterized in passing the particles at said starting area into a zone above an annular horizontal aperture of a diameter less than the diameter of said vertical pipe, from which aperture a swirling flow of drying and carrying gas is emitted at a momentum accelerating and controlling the flow of particles in a rotation-symmetrical, hollow zone above the annular aperture and around an imaginary vertical centre line of said aperture;

• and from a location on said imaginary centre line producing an upward spray of droplets of granulation liquid hitting the particles while these are in said zone thereby creating efficient contact between wet sticky particles combined with a fast drying to produce stable granules leaving the top of the granulation pipe in a non sticky condition.