Method of defluorinating rock phosphate

Claim 1

THE CONTINUOUS METHOD OF DEFLUORINATING ROCK PHOSPHATE SO AS TO MAKE IT SUITABLE FOR ANIMAL FEED, WHICH COMPRISES, MAINTAINING A DOWNWARDLY MOVING BURDEN OF ROCK PHOSPHATE AND COKE IN LOOSE CONDITION IN THE VERTICAL SHAFT AND A BLAST FURNACE, CHARGING ADDITIONAL ROCK PHOSPHATE AND COKE ONTO THE TOP OF SAID DOWNWARDLY MOVING BURDEN, CONTINUOUSLY INTRODUCING A BLAST OF AIR INTO SAID FURNACE AT A LEVEL SUBSTANTIALLY ABOUT THE BOTTOM THEREOF SO AS TO CONTINUOUSLY IGNITE THE COKE AND MELT THE ROCK PHOSPHATE IN SAID BURDEN AS THEY REACH A LEVEL ADJACENT SAID AIR BLAST INTRODUCTION LEVEL, CONTINUOUSLY INTRODUCING THE HOT GASEOUS PRODUCTS OF COMBUSTION OF A HYDROCARBON FUEL INTO SAID FURNACE BELOW SAID AIR BLAST INTRODUCTION LEVEL, AND CONTINUOUSLY WITHDRAWING MOLTEN DEFLUORINATED ROCK PHOSPHATE SLAG THROUGH A CONTINUOUSLY OPEN BLAST AND SLAG OUTLET OPENING IN THE BOTTOM OF SAID FURNACE, SAID AIR BLAST BEING SUFFICIENT TO CONTINUOUSLY BURN ALL OF THE COKE IN SAID BURDEN IN THE BOTTOM OF SAID FURNACE, MAINTAINING THE TEMPERATURE IN THE BOTTOM OF SAID FURNACE IN THE RANGE OF 3,000* F. TO 3,300* F. BY THE BURNING OF SAID COKE AND BY SAID HOT GASEOUS PRODUCTS OF COMBUSTION, AND SAID MOLTEN ROCK PHOSPHATE BEING DEFLUORINATED AS IT TRICKLES DOWNWARDLY THROUGH THE BOTTOM OF SAID FURNACE TO SAID OPEN BLAST AND SLAG OUTLET OPENING.