Process and apparatus for separating particles by relative density

A method for concentrating particles of relatively greater density contained in an aggregated mass of particles of selected size having different densities, comprising:

• disposing the particles on a generally horizontal supporting surface to form a particle bed;
• agitating said supporting surface with a motion effective to fluidize the particle bed and thereby reduce the resistance of said bed to the lateral movement of particles therein;
• simultaneously contacting the particles in said fluidized bed with a plurality of spaced apart annular vertical reaction surfaces moveable with the supporting surface and having a laterally eccentric motion effective to induce a lateral movement of particles within the fluidized particle bed, said vertical reaction surface defining at least one collection region and at least one adjacent annular region;
• providing limited areas of communication between adjacent annular regions for the net movement of particles of relatively greater density therethrough from said one region into said collecting region;
• adding particles to said fluidized particle bed in an amount sufficient to raise the particle bed to a level permitting excess particles to disperse laterally over the top of at least one of said vertical reaction surfaces;
• and
• contacting said particles at the top of said fluidized bed with a laterally extending reaction surface having a reciprocal vertical motion relative to said dispersed particles so as to cause excess particles of greater density to enter said annular regions within the fluidized bed in preference to particles of lesser density.

A method for concentrating particles of selected relative density from an aggregated mass of size-classified particles having different individual densities, comprising:

• disposing said particles upon a laterally extending supporting surface to form a particle bed;
• agitating said supporting surface with a motion effective to fluidize said particle bed and thereby reduce the resistance thereof to lateral movement of particles therewithin;
• simultaneously contacting the particles in said fluidized bed with a plurality of annular vertical reaction surfaces movable with the supporting surface and having a laterally eccentric motion, said vertical reaction surfaces defining a plurality of adjacent annular regions;
• providing areas of limited communication between adjacent regions so as to permit the movement of particles from one region to the next toward a collection region;
• simultaneously contacting the particles of said fluidized bed in said collection region with a plurality of mutually spaced, horizontal reaction surfaces so as to enhance the fluidity of particles therewithin and thereby to permit the more dense particles to move into and remain in the collection zone in preference to particles of lesser density;
• contacting any excess particles at the top of said fluidized bed with an auxiliary vertical reaction surface having a laterally eccentric motion, thereby to disperse excess particles in a direction counter to the net direction of dense particles within the fluidized bed;
• contacting said dispersed particles at the top of said fluidized bed with a laterally extending reaction surface having a vertical repetitive motion relative to the particle bed, thereby to drive at least the denser excess particles into the fluidized bed within said annular regions, and
• permitting less dense excess particles to exit from the particle bed.

An apparatus for separating particles of selected relative density from an aggregated group of particles of predetermined size, having different individual densities, comprising:

• a lateral surface for supporting a bed of particles disposed thereon;
• means for agitating said supporting surface with a motion effective to fluidize said particle bed and thereby reduce the resistance of said bed to the lateral movement of particles therein;
• a plurality of spaced-apart annular vertical reaction surfaces movable with said lateral supporting surface and defining at least one collection region and at least one adjacent annular region, said vertical reaction surfaces having passages therethrough for intercommunicating adjacent ones of the annular regions;
• means for giving said annular vertical reaction surfaces a laterally eccentric motion so as to contact the particles in said fluidized bed and induce a lateral movement of particles therewithin toward said collection region;
• a plurality of vertically spaced horizontal reaction surfaces disposed in said collection region and movable with the supporting surface so as to enhance the fluidity of particles therewithin, thereby to enable denser particles to move into and remain in the collection zone in preference to less dense particles;
• and
• means providing a vertical barrier surface in said collection zone to which more dense particles may move laterally between said horizontal reaction surfaces and there remain in preference to less dense particles.

Apparatus for concentrating particles of relatively greater density contained in an aggregated mass of particles of selected size, having different densities, comprising:

• means providing a lateral supporting surface for said particles to form a particle bed:
• means for agitating said supporting surface to fluidize the particle bed and thereby reduce the resistance of said bed to the lateral movement of particles therewithin:
• a plurality of spaced-apart annular vertical reaction surfaces defining a collection region and at least one adjacent annular region within the particle bed, said annular surfaces being movable with the supporting surface in a laterally eccentric motion to induce a lateral movement of particles in the fluidized particle bed;
• said annular reaction surfaces having limited areas of communication therethrough for the net movement of particles of relatively greater density from said one annular region into said collection region;
• and
• a lid at the top of said fluidized bed and movable with the supporting surface so as to contact any excess particles at the top of the fluidized bed and urge the particles of greater density therein to enter said annular region in preference to particles of lesser density.

Apparatus for concentrating particles of relatively greater density contained in an aggregated mass of classified particles having different densities, comprising:

• a lateral supporting surface for the particles to form a particle bed;
• a plurality of radially spaced rings carried by said supporting surface and defining at least one collection region and at least one adjacent annular region, one of said rings having a restricted opening therein to permit the limited passage of particles between annular regions;
• means for imparting to said supporting surface a gyratory-like motion having a repetitive vertical motion component and a laterally eccentric motion component, said motion being effective to fluidize the particle bed to reduce the resistance thereof to individual particle movement therewithin and to induce a net lateral movement of the denser particles toward said collection region;
• and
• means associated with said collection region for enhancing the fluidity of particles therewithin while permitting denser particles to move into said collection region and there remain in preference to particles of less density.

Apparatus for concentrating particles of relatively greater density contained in an aggregated mass of classified particles having different densities, comprising:

• a lateral supporting surface for the particles to form a particle bed;
• a plurality of radially spaced rings carried by said supporting surface and defining at least one collection region and at least one adjacent annular region, one of said rings having a restricted opening therein to permit the limited passage of particles between annular regions;
• means for imparting to said supporting surface a gyratory-like motion having a repetitive vertical motion component and a laterally eccentric motion component, said motion being effective to fluidize the particle bed to reduce the resistance thereof to individual particle movement therewithin and to induce a net lateral movement of the denser particles toward said collection region;
• and
• means for dispersing excess particles over the top of the fluidized particle bed;
• and
• means for imparting a downward momentum to said dispersed particles to urge at least the denser of said excess particles to enter the fluidized particle bed of at least one of said regions.