Sulphur recovery

Claim 1

IN THE TREATMENT OF PARTICLES OF SOLID MATERIAL CONTAINING ELEMENTAL SULPHUR TO RECOVER THE LATTER, THE IMPROVEMENT WHICH COMPRISES INTRODUCING THE SOLID MATERIAL CONTAINING NOT TO EXCEED ABOUT 5% MOISTURE INTO A HEAT ING ZONE, PASSING A THIN BED OF THE PARTICLES CONTINUOUSLY OVER A HEARTH IN THE HEATING ZONE WHILE SUBJECTING THESE PARTICLES TO AGITATION, MAINTAINING THE HEATING ZONE AT A TEMPERATURE ABOVE THE MELTING POINT OF SULFUR, HEATING THE PARTICLES PASSING THROUGH THE ZONE FROM BELOW THE MELTING POINT OF SULPHUR TO ABOVE THE MELTING POINT OF SULPHUR SO RAPIDLY THAT THE PROPORTION OF THE SULFUR EXISTING IN HOT VISCOUS STATE IN INSUFFICIENT TO BRING ABOUT THE FORMATION OF SUBSTANTIAL AGGREGATES OF THE PARTICLERS IN THE BED BY CEMENTING DUE TO THE PRESENCE OF THE VISCOUS SULPHUR, THE HEATING OF THE PARTICLES BEING ACCOMPLISHED BY PASSING THROUGH THE ZONE IN CONTACT WITH THE PARTICLES A HOT STREAM OF SUBSTANTIALLY NON-REACTIVE GASEOUS COMBUSTION PRODUCTS OF CARBONCEOUS FUEL AND AIR HIGH IN CO2 AND CONTAINING SUBSTANTIALLY NO CO AND NO OXYGEN, CONTINUSOUSLY WITHDRAWING FROM THE ZONE THE RESULTING MIXTURE OF GAS AND SULPHUR VAPOR AT A TEMPERATURE BELOW 1475* F., PARTIALLY COOLING THE WITHDRAW MIXTURE BY INDIRECT HEAT EXCHANGE TO A TEMPERATURE SUBSTANTIALLY BELOW 850* F. BUT WITHOUT REMOVING ANY SUBSTANTIAL QUANTITY OF SULPHUR FROM THE PARTIALLY COOLED MIXTURE AND THEREAFTER BRINGING THE PARTIALLY COOLED MIXTURE INTO CONTACT WITH LIQUID SULPHUR TO REMOVE THE SULPHUR FROM THE GASEOUS MIXTURE.