Apparatus and process for circulating powdered solid in chemical treatment

Claim 1

A CONTINUOUS METHOD FOR CONDUCTING A CHEMICAL TREATMENT OF A GASIFORM MATERIAL WITH A POWDERED SOLID MATERIAL, WHICH COMPRISES FLOWING FRESH POWDERED SOLID MATERIAL BY GRAVITY IN AN ELONGATED CONFINED STREAM TO A BOTTOM INLET OF A VERTICALLY ELONGATED CYLINDRICAL TREATING ZONE, ADMIXING A STREAM OF GASIFORM MATERIAL WITH SAID POWDERED SOLID MATERIAL PASSING INTO SAID INLET, FORCING THE RESULTING MIXTURE OF THE GASIFORM AND POWDERED SOLID MATERIAL UPWARDLY IN THE FORM OF SEPARATED STREAMS OF SHORT LENGTH INTO THE TREATING ZONE TO FORM A DENSE TURBULENT SUSPENSION OF THE POWDERED SOLID MATERIAL IN THE GASIFORM MATERIAL, SAID DENSE SUSPENSION HAVING AN UPPER LEVEL AT THE TOP OF SAID TREATING ZONE, AND BEING OF UNIFORM HIGH CONCENTRATION, PASSING GASIFORM MATERIAL UPWARDLY FROM THE TREATING ZONE THROUGH A SUPERIMPOSED SEPARATION ZONE OF GREATER DIAMETER THAN THE TREATING ZONE SO THAT ENTRAINED POWDERED SOLID MATERIAL EXCEPT FOR A SMALL AMOUNT OF FINER PARTICLES DROPS FROM THE GASIFORM MATERIAL AND IS RETURNED DIRECTLY DOWN INTO THE TREATIN ZONE AS THE GASIFORM MAMATERIAL PASSES THROUGH THE SEPARATION ZONE AT A REDUCED VELOCITY, PASSING THE GASIFORM MATERIAL CARRYING THE FINER PARTICLES OVERHEAD FROM SAID SEPARATION ZONE INT A SECOND SEPARATION ZONE IN WHICH SAID FINER PARTICLES ARE SEPARATED, AND RECIRCULATING SAID FINER PARTICLES THUS SEPARATED BY ADDING THEM TO THE FRESH POWDERED MATERIAL AS IT IS FED INTO SAID ELONGATED CONFINED STREAM AT A POINT ELEVATED ABOVE SAID TREATING ZONE.