Method of chloridizing sintering of zinciferous materials with elimination of lead and similar contaminants

Claim 1

IN TH PROCESS OF FORMING A CHLORIDIZED SINTER OF ZINCIFEROUS MATERIAL CONTAINING IN EXCESS OF 1% OF LEAD TO ELIMINATE LEAD AND ANY OTHER ASSOCIATED METAL AND METALLOID IMPURITIES THEREFROM WHEREIN THE ZINCIFEROUS MATERIAL IS PREPARED FOR THE SINTERING TREATMENT BY SUBJECTING A MIXTURE OF SAID ORE, FUEL AND A CHLORIDIZING AGENT TO A PELLETIZING TREATMENT WITH ADDITION OF SUFFICIENT WATER AND A BINDER TO BIND THE MIXTURE INTO SELF-SUBSTAINING PELLETS; THE IMPROVEMENT WHICH CONSISTS IN INCREASING THE POROSITY OF THE CHARGE IN A STEP PRELIMINARY TO THE IGNITION OF THE CHARGE BY DRYING THE PELLETS TO SUBSTANTIAL DRYNESS WHILE DISPOSED IN SITU ON A SINTERING GRATE AND THEREBY CONCOMITANTLY DECREASING THE FUEL REQUIREMENTS OF THE CHARGE, THEREAFTER APPLYING A BLAST FLAME TO THE UPPER SIDE OF SAID CHARGE AND APPLYING SUCTION AT THE GRATE SIDE TO DRAW AIR AND COMBUSTION PRODUCTS THROUGH SAID CHARGE WHILE THE CHARGE IS DISPOSED IN A RELATIVELY THIN LAYER ON THE SINTERING GRATE, THE SUCTION AND THE AMOUNT OF FUEL BEING SUPPLIED TO THE BLAST FLAME BEING REGULATED SO AS TO MAINTAIN A TEMPERATURE OF AT LEAST 1200* C. AS MEASURED APPROXIMATELY ONE INCH FROM THE BOTTOM OF THE BED AS IT IS DISPOSED ON THE SINTERING GRATE BUT BELOW THE TEMPERATURE AT WHICH FUSION OF THE CHARGE WILL OCCUR, THEREBY CHLORIDIZING AND VAPORIZING THE LEAD AND OTHER ASSOCIATED METAL AND METALLOID IMPURITIES, AND WITHDRAWING SAID VAPORIZED CHLORIDES AS FORMED.