Drying and cleaning of small or fine coal, or other particulate materials, containing components of different specific gravities

Claim 1

A PROCESS FOR CLEANING IMPURE SMALL COAL OR OTHER PARTICULATE MATERIAL, HAVING COMPONENTS OF DIFFERENT SPECIFIC GRAVITIES INCLUDING COMPONENTS OF RELATIVELY HIGH AND LOW SPECIFIC GRAVITIES, COMPRISING DELIVERING SAID MATERIAL INTO A FIRST FLUIDISED BED FORMED BY SAID MATERIAL ITSELF TO EFFECT A DRYING AND DE-DUSTING OF SAID MATERIAL, DISCHARGING SAID MATERIAL FROM SAID FIRST FLUIDISED BED BY OVERFLOWING THEREFROM AT SUBSTANTIALLY THE WHOLE PERIPHERY OF SAID BED, DELIVERING SAID DISCHARGED MATERIAL TO AT LEAST ONE FURTHER FLUIDISED BED COMPOSED OF DISCRETE SOLID PARTICLES HAVING A SPECIFIC GRAVITY INTERMEDIATE THAT OF SAID HIGH AND LOW SPECIFIC GRAVITY COMPONENTS, MAINTAINING SAID FURTHER FLUIDISED BED IN A FLUIDISED CONDITION BY A GASEOUS MEDIUM APPLIED THERETO FROM BELOW IN SUCH MANNER AS TO GIVE AND RETAIN IN SAID FURTHER BED A SPECIFIC GRAVITY EFECTIVE TO CAUSE SEPARATION OF SAID MATERIAL INTO COMPONENTS OF RELATIVELY HIGH AND LOW SPECIFIC GRAVITY, THE LOW SPECIFIC GRAVITY COMPONENT BEING CAUSED TO DISCHARGE FROM SAID FURTHER BED BY OVERFLOWING THEREFROM AT SUBSTANTIALLY THE WHOLE PERIPHERY THEREOF.