1. METHOD OF TREATING A MIXTURE OF PARTICLES OF AT LEAST TWO DIFFERENT MATERIALS TO SEPARATE PARTICLES OF A FIRST OF SAID MATERIALS FROM SAID MIXTURE, COMPRISING THE STEPS OF PROPELLING A GAS THROUGH SAID MIXTURE AND THEREBY FLUIDIZING SAID MIXTURE IN A GASEOUS MEDIUM, PROPELLING THE FLUIDIZED MIXTURE PAST A SOURCE OF ENERGY FOR APPLYING TO THE FLUIDIZED MIXTURE ENERGY WHICH SELECTIVELY HEATS PARTICLES OF SAID FIRST MATERIAL TO A HIGHER TEMPERATURE THAN PARTICLES OF THE REMAINDER OF SAID MIXTURE, THEREAFTER PROPELLING SAID FLUIDIZING MIXTURE WITH SAID SELECTIVELY HEATED PARTICLES TOWARD A TEMPERATURE SENSITIVE BODY AND SELECTIVELY CAPTURING HEATED PARTICLES OF SAID FIRST MATERIAL WITH SAID TEMPERATURE-SENSITIVE BODY IN CONTACT THEREWITH, THE SAME GAS BEING EMPLOYED UNDER PRESSURE FOR FLUIDIZING SAID MIXTURE AND FOR PROPELLING THE SAME SUCCESSIVELY PAST SAID SOURCE AND TOWARD SAID BODY.