System for feeding grinding media to continuous attrition mill

Claim 1

In an apparatus for grinding particulate solids by the grinding action of grinding particles which are substantially larger than the solids being ground, comprising a vertical cylindrical vessel having an inlet in the lower portion thereof, an annular suppression plate mounted in an upper region of said vessel, the opening in said suppression plate being generally centered therein, a rotatable member extending through said opening and into said vEssel generally along the cylindrical axis of the vessel, a horizontal disc mounted on said rotatable member immediately below the suppression plate and a plurality of impellers within said vessel attached to said rotatable member below said disc, the improvement which comprises providing a grinding medium feed pipe extending downwardly through a separate opening in said suppression plate and terminating a small distance above said rotatable disc, the opening in said suppression plate being of such diameter and the disc being so spaced from the lower surface of said suppression plate and the lower end of said grinding medium feed pipe that during operation particles below a predetermined size pass upwardly through the suppression plate opening out of the vessel as product while fresh grinding medium particles enter the vessel between the rotatable disc and feed pipe.