Method for the production and recovery of sodium aluminum fluorides

Claim 1

A METHOD OF PRODUCING CRYOLITE OF AT LEAST 90% PURITY FROM MATERIALS CONTAINING COMPOUNDS OF ALUMINUM WITH FLUORINE, COMPRISING THE STEPS OF LEACHING SAID MATERIALS WITH AQUEOUS SODIUM HYDROXIDE SOLUTION SO AS TO OBTAIN A FIRST AQUEOUS SOLUTION OF ALKALINE PH HAVING DISSOLVED THEREIN COMPOUNDS INCLUDING FLUORINE, ALUMINUM AND SODIUM, AND ALSO TO OBTAIN A SOLID RESIDUE STILL CONTAINING A PORTION OF ALUMINUM ORIGINALLY CONTAINED IN SAID MATERIALS, SEPARATING SAID FIRST AQUEOUS SOLUTION FROM SAID SOLID RESIDUE, LEACHING SAID SOLID RESIDUE WITH AQUEOUS HYDROFLUORIC ACID SO AS TO OBTAIN A SECOND AQUEOUS SOLUTION OF ACIDIC PH HAVING DISSOLVED THEREIN COMPOUNDS INCLUDING ALUMIUM AND FLUORINE AND ALSO TO OBTAIN ANOTHER SOLID RESIDUE, SEPARATING SAID SECOND AQUEOUS SOLUTION FROM SAID OTHER SOLID RESIDUE, AND COMBINING SAID FIRST AQUEOUS SOLUTION WITH SAID SECOND AQUEOUS SOLUBY FORMING A PRECIPITATE CONSISTING OF CRYOLITE HAVING A PURITY HIGHER THAN 90%.

Claim 2

A METHOD OF PRODUCING CRYOLITE OF AT LEAST 90% PURITY FROM MATERIALS CONTAINING COMPOUNDS OF ALUMINUM WITH FLUORINE, COMPRISING THE STEPS OF LEACHING SAID MATERIALS WITH AQUEOUS SODIUM HYDROXIDE SOLUTION SO AS TO OBTAIN A FIRST AQUEOUS SOLUTION OF ALKALINE PH HAVING DISSOLVED THEREIN COMPOUNDS INCLUDING FLUORINE, ALUMINUM AND SODIUM, AND ALSO TO OBTAIN A SOLID RESIDUE STILL CONTAINING A PORTION OF ALUMINUM ORIGINALLY CONTAINED IN SAID MATERIALS, SEPARATING SAID FIRST AQUEOUS SOLUTION FROM SAID SOLID RESIDUE, LEACHING SAID SOLID RESIDUE WITH AQUEOUS HYDROFLUORIC ACID SO AS TO OBTAIN A SECOND AQUEOUS SOLUTION OF ACIDIC PH HAVING DISSOLVED THEREIN COMPOUNDS INCLUDING ALUMIUM AND FLUORINE AND ALSO TO OBTAIN ANOTHER SOLID RESIDUE, SEPARATING SAID SECOND AQUEOUS SOLUTION FROM SAID OTHER SOLID RESIDUE, AND COMBINING SAID FIRST AQUEOUS SOLUTION WITH SAID SECOND AQUEOUS SOLUBY FORMING A PRECIPITATE CONSISTING OF CRYOLITE HAVING A PURITY HIGHER THAN 90%.