Flotation concentration of non-metallic minerals containing calcite

Claim 1

A PROCESS FOR RECOVERING A HIGH GRADE CONCENTRATE IN THE TREATMENT OF A NON-METALLIC MINERAL CONTAINING CALCITE SAID MINERAL BEING SELECTED FROM THE GROUP CONSISTING OF SCHEELITE, WOLFRAMITE, POWELLITE, APATITE, FLUORITE AND RHODOCHROSITE, WHICH COMPRISES SUBJECTING A PULP OF SUCH A MINERAL IN A FLOTATION SIZE RANGE TO A FROTH FLOTATION TREATMENT IN THE PRESENCE OF A COLLECTOR REAGENT FOR SAID MINERAL SO AS TO COLLECT MOST OF SAID MINERAL AND SOME OF THE CALCITE AS A BULK CONCENTRATE PRODUCT, DRYING SAID CONCENTRATE PRODUCT, HEATING THE DRY CONCENTRATE IN A FLAME-FREE ATMOSPHERE TO TEMPERATURES ABOVE 500*F. BUT NOT EXCEEDING 930*F. DURING WHICH THE CALCITE SURFACES ARE ALTERED WITHOUT CALCITE DECOMPOSITION AND THE MINERAL SURFACES REMAIN UNALTERED SO AS TO RENDER THE CALCITE INERT TO COLLECTOR REAGENTS FOR THE MINERAL, PULPING THE HOT CONCENTRATE WITH AN AQUEOUS SOLUTION, CONDITIONING THE AQUEOUS PULP FOR FLOTATION BY INTRODUCING A COLLECTOR REAGENT FOR THE MINERAL, AN ALKALINE REAGENT AND A RETARDER FOR MIXING WITH THE PULPP, AND SUBJECTING THE CONDITIONED PULP TO A FROTH FLOTATION TREATMENT SO AS TO CONCENTRATE THE MINERAL IN A FROTH SUBSTANTIALLY FREE OF CALCITE CONTAMINANTS.