Process for recovery of hf and sio2 from waste gases

Claim 1

A PROCESS FOR TREATING WASTE GASES OBTAINED FROM PROCESS, INCLUDING ACIDULATION OF PHOSPHATIC MINERALS WITH ALKYLATION-GRADE SULFURIC ACID, WHICH WASTE GASES CONTAIN FLUORINE AND SILICA IN AT LEAST ONE OF THE FORMS SIF4 AND H2SIF6, FLUORINE IN THE FORM OF HF, SIO2 IN SUSPENSION, H2O VAPOR AND COMBUSTIBLE CARBONACEOUS MATERIALS, WHICH COMPRISES ADMIXING A FUEL WITH THE WASTE GASES, THE AMOUNT OF SAID FUEL BEING SUFFICIENT TO INITIATE COMBUSTION OF THE WASTE GASES WHEN THEY ARE HEATED TO THEIR COMBUSTION TEMPERATURE, ESTABLISHING THE CONTENT OF THE CARBONACEOUS MATERIAL IN THE WASTE GASES SO THAT COMBUSTION OF SAID GASES, ONCE INITIATED, WILL CONTINUE WITHOUT FURTHER FUEL ADMIXING, HEATING SAID WASTE GASES TO A TEMPERATURE BETWEEN ABOUT 800*F. AND ABOUT 3000*F. SO AS TO INITIATE COMBUSTION THEREOF, AND THEREAFTER, DISCONTINUING ADMIXING OF SAID FUEL, WHEREBY THE COMBUSTION IS MAINTAINED UNTIL SUBSTANTIALLY COMPLETE COMBUSTION OF THE WASTE GASES IS OBTAINED AND THE HYDROGEN FLUORIDE AND SILICA PRODUCED ARE IN RECOVERALBE FORM.