Chemical treatment of finely divided solids

Claim 1

THE PROCESS OF TREATING FINELY DIVIDED SOLID MINERAL MATERIAL AT ELEVATED TEMPERATURE WITH GAS REACTIVE WITH A COMPONENT OF SAID MINERAL MATERIALS, WHICH COMPRISES CONTINUOUSLY FEEDING SAID FINELY DIVIDED SOLID MINERAL MATERIAL INITIALLY INTO A PRIMARY TREATING ZONE TO FORM A LAYER OF SAID MATERIAL IN SAID ZONE, CONTINUOUSLY WITHDRAWING SOLID MATERIAL FROM SAID LAYER TO FORM A SECOND LAYER OF SOLID MATERIAL WITHIN SAID ZONE, SAID CONTINUOUS FEEDING AND WITHDRAWING BEING CONTINUED TO PROVIDE A PLURALITY OF SUCH LAYERS AT SPACED LEVELS IN SAID ZONE, INTRODUCING INTO A MIXING ZONE BELOW THE LOWERMOST FINAL LAYER THUS FORMED IN SAID PRIMARY TREATING ZONE A GAS HEATED TO AT LEAST MAXIMUM DESIRED REACTION TEMPERATURE, FURTHER INTRODUCING INTO SAID MIXING ZONE A CONCENTRATED REACTIVE GAS IN SUBSTANTIALLY SMALLER VOLUME THAN SAID HEATED GAS, EFFECTING MIXING OF SAID CONCENTRATED REACTIVE GAS WITH SAID HEATED GAS IN SAID MIXING ZONE TO FORM A DILUTED HOT TREATING GAS, FLOWING THE DILUTED HOT TREATING GAS INTO SAID FINAL LAYER AT A RATE SUFFICIENT TO SUSPEND THE SOLID MATERIAL IN SAID LAYER TO FORM A DENSE TURBULENT FLUIDIZED MASS, SEPARATING DILUTE HOT TREATING GAS FROM SAID FINAL LAYER AND FLOWING THE SEPARATED GAS TO THE NEXT HIGHER LAYER TO EFFECT SUSPENSION OF THE SOLID MATERIAL IN SAID LAYER TO FORM A DENSE TURBULENT FLUIDIZED MASS, SEPARATING HOT DILUTE TREATING GAS FROM SAID LAST NAMED LAYER AND SUCCESSIVELY FLOWING THE SEPARATED GAS IN LIKE MANNER TO SUSPEND EACH SUCCEEDING HIGHER LAYER AND FINALLY TO THE FIRST AND HIGHEST LAYER FORMED BY THE CONTINUOUS INITIAL FEEDING OF SOLID MINERAL MATERIALS AND THEREAFTER DISCHARGING SEPARATED GAS FROM SAID HIGHEST LAYER; THE TEMPERATURE OF SAID DILUTED HOT TREATING GAS BEING REDUCED IN FLOWING SUCCESSIVELY THROUGH THE SEVERAL LAYERS WHILE THE TEMPERATURE OF SAID SOLID MATERIAL IS INCREASED PROGRESSIVELY IN DESCENT FROM SAID HIGHEST LAYER TO SAID LOWERMOST LAYER AS A RESULT OF DIRECT HEAT EXCHANGE IN CONTACT BETWEEN SAID DILUTED HOT TREATING GAS AND SAID SOLID MATERIAL; WITHDRAWING THE THUS HEATED AND TREATED SOLID MATERIAL FROM SAID LOWERMOST LAYER OF SAID PRIMARY TREATING ZONE AND CONTACTING THE WITHDRAWN SOLID MATERIAL DIRECTLY WITH CONCENTRATED REACTIVE GAS INTRODUCED AT A TEMPERATURE LOWER THAN THE TEMPERATURE OF SAID SOLID MATERIAL, AND CONCENTRATED REACTIVE GAS BEING FLOWED AT A RATE SUFFICIENT TO SUSPEND THE SOLID MATERIAL THUS CONTACTED IN DENSE TURBULENT FLUIDIZED CONDITION, SEPARATING CONCENTRATED REACTIVE GAS FROM CONTACT WITH SAID SOLID MATERIAL AND ADMITTING THE SEPARATED GAS TO THE AFORESAID MIXING ZONE, CONTINUOUSLY WITHDRAWING SOLID MATERIAL AFTER CONTACT WITH THE CONCENTRATED REACTIVE GAS, CONTACTING THE SOLID MATERIAL THUS WITHDRAWN WITH COOL INERT GAS, ADMIXING COOL INERT GAS WITH REACTIVE GAS TO FORM BY THE ADMIXTURE SAID CONCENTRATED REACTIVE GAS HEREINBEFORE SPECIFIED, AND FINALLY DISCHARGING TREATED SOLID MATERIAL IN COOLED CONDITION.