Process for recovery of tungsten from scheelite and wolframite ores

Claim 2

A PROCESS OF RECOVERING TUNGSTEN VALUES FROM SCHEELITE OR WOLFRAMITE TYPE ORES OR CONCENTRATES, WHICH COMPRISES FUSING SUCH A MATERIAL IN POWDERED FORM WITH A MIXTURE OF SODIUM CARBONATE AND SODIUM CHLORIDE CONTAINING SUFFICIENT SILICA COMPOUNDS TO FORM CALCIUM SILICATE WITH ANY CALCIUM OXIDE COMBINED WITH THE TUNGSTEN AND AT A TEMPERATURE NOT LESS THAN 698*C., LEACHING THE FUSED MATERIAL IN WATER, SEPARATING THE TUNGSTEN-BEARING ALKALINE LEACH LIQUOR FROM IMPURITIES, INTRODUCING AN ALKALI SULFIDE INTO THE LEACH LIQUOR IN A QUANTITY SUFFICIENT TO FORM A SOLUBLE SULFIDE COMPOUND WITH ANTIMONY, ARSENIC AND MOLYBDENUM PRESENT, ACIDIFYING THE LEACH LIQUOR AFTER SULFIDE INTRODUCTIONA TO ESTABLISH A PH BETWEEN 5 AND 7, SEPARATING THE IMPURITIES FROM THE ACIDIFIED LEACH LIQUOR BY FILTRATION, ADDING ACID TO THE SEPARATED SOLUTION OF FILTRATION TO ESTABLISH A PH LESS THAN 4, SUBJECTING THE ACIDIFIED SOLUTION TO HEATING, REMOVING MOLYBDENUM RESIDUES FROM THE ACIDIFIED SOLUTION BY FILTRATION, ADDING A SOLUBLE HYDROFLUORIC ACID MATERIAL TO THE SOLUTION AFTER MOLYBDENUM REMOVAL TO GIVE AT LEAST 6 MOLECULES OF FLUORINE FOR EVERY MOLECULE OF SILICA AND PHOSPHORUS CONTAINED IN THE SOLUTION, EXTRACTING THE ANIONIC TUNGSTEN COMPONENT OF THE AQUEOUS SOLUTION WITH A WATER-INSOLUBLE REAGENT SELECTED FROM THE GROUP CONSISTING OF TERTIARY TRIDECYL, TRIAMYL, TRIISOOCTYL AND TRILAURYL AMINES IN A DILUENT SELECTED FROM THE GROUP CONSISTNG OF KETONES AND KEROSENE WHILE THE CATIONIC SODIUM COMPONENT REMAINS IN THE AQUEOUS SOLUTION, STRIPPING THE ORGANIC EXTRACTANT CONTAINING TUNGSTEN WITH A DILUTE AMMONIUM HYDROXIDE SOLUTION HAVING AN EXCESS OF AMMONIA TO ESTABLISH A PH OF AT LEAST 7.5, EVAPORATING THE TUNGSTEN-BEARING STRIP SOLUTION TO PRECIPITATE CRYSTALLINE AMMONIUM PARATUNGSTATE, AND DISCHARGING DRIED AMMONIUM PARATUNGSTATE FROM THE TREATMENT AS A FINAL PRODUCT.

Claim 3

A PROCESS OF RECOVERING TUNGSTEN VALUES FROM SCHEELITE OR WOLFRAMITE TYPE ORES OR CONCENTRATES HAVING SOME CALCIUM, SILICA, PHOSPHOROUS, ARSENIC AND ANTIMONY COMPONENTS AND SUBSTANTIALLY NO MOLYBDENUM, WHICH COMPRISES FUSING SUCH A MATERIAL IN POWDERED FORM WITH A MIXTURE OF SODIUM CARBONATE AND SODIUM CHLORIDE CONTAINING SUFFICIENT SILICA COMPOUNDS TO FORM CALCIUM SILICATE WITH ANY CALCIUM OXIDE COMBINED WITH THE TUNGSTEN AND AT A TEMPERATURE NOT LESS THAN 698*C. THEREBY CONVERTING TUNGSTEN COMPOUNDS IN THE ORE TO SOLUBLE SODIUM TUNGSTATE AND LEAVING SOME IMPURITIES PRESENT IN THE ORE AS INSOLUBLE MATERIAL, LEACHING THE FUSED MATERIAL IN WATER TO DISSOLVE THE SODIUM TUNGSTATE, REMOVING ATHE INSOLUBLE RESIDUE FROM THE AQUEOUS LEACH LIQUOR BY FILTRATION, INTRODUCING AN ALKALI SULFIDE INTO THE LEACH LIQUOR IN A QUANTITY SUFFICIENT TO FORM A SOLUBLE SULFIDE COMPOUND WITH ANTIMONY OR ARSENIC COMPONENTS PRESENT IN THE LEACH LIQUOR, ACIDIFYING THE LEACHED LIQUOR WITH SULFURIC ACID AFTER SULFIDE INTRODUCTION TO ESTABLISH A PH BETWEEN 5 AND 7, SEPARATING THE IMPURITIES FROM THE ACIDIFIED LEACH LIQUOR BY FILTRATION, ADDING FLUORINE IN THE FORM OF A SOLUBLE FLUORINE SALT OR HYDROFLUORIC ACID TO THE LIQUOR IN A QUANTITY TO GIVE AT LEAST 6 MOLECULES OF FLUORINE FOR EVERY MOLECULE OF SILICA AND PHOSPHOROUS CONTAINED IN THE SOLUTION SAID LIQUOR BEING ACIDIFIED TO A PH LESS THAN 4 BEFORE FLUORINE INTRODUCTION, EXTRACTING THE ANIONIC TUNGSTEN COMPONENT OF THE FLUORINE TREATED ACIDIC SOLUTION WITH A WATER-INSOLUBLE REAGENT SELECTED FROM THE GROUP CONSISTING OF TERTIARY TRIDECYL, TRIAMYL, TRIISOOCTYL AND TRILAURYL AMINES IN A DILUENT SELECTED FROM THE GROUP CONSISTING OF KETONES AND KEROSENE WHILE THE CATIONIC SODIUM COMPONENT REMAINS IN THE AQUEOUS SOLUTION, STRIPPING THE ORGANIC EXTRACTANT CONTAINING TUNGSTEN WITH A DILUTE AMMONIUM HYDROXIDE SOLUTION HAVING AN EXCESS OF AMMONIA TO ESTABLISH A PH OF AT LEAST 7.5, CLAYRIFYING THE AMMONIUM HYDROXIDE SOLUTION CONTAINING THE EXTRACTED TUNGSTEN BY FILTRATION, SUBJECTING THE CLARIFIED SOLUTION TO EVAPORATION TO EXPEL MOST OF THE WATER AND CONTAINED AMMONIA AND PRECIPITATE CRYSTALLINE AMMONIUM PARATUNGSTATE, AND DISCHARGING DRIED AMMONIUM PARATUNGSTATE CRYSTALS AS A FINAL PRODUCT OF THE TREATMENT.

Claim 4

A PROCESS OF RECOVERING TUNGSTEN VALUES FROM SCHEELITE OR WOLFRAMITE TYPE ORES OR CONCENTRATES HAVING SOME CALCIUM, SILICA, PHOSPHOROUS, ARSENIC AND ANTIMONY COMPONENTS AND SUBSTANTIALLY NO MOLYBDENUM, WHICH COMPRISES FUSING SUCH A MATERIAL IN POWDERED FORM WITH A MIXTURE OF SODIUM CARBONATE AND SODIUM CHLORIDE CONTAINING SUFFICIENT SILICA COMPOUNDS TO FORM CALCIUM SILICATE WITH ANY CALCIUM OXIDE COMBINED WITH THE TUNGSTEN AND AT A TEMPERATURE NOT LESS THAN 698*C. THEREBY CONVERTING TUNGSTEN COMPOUNDS IN THE ORE TO SOLUBLE SODIUM TUNGSTATE AND LEAVING SOME IMPURITIES PRESENT IN THE ORE AS INSOLUBLE MATERIAL, LEACHING THE FUSED MATERIAL IN WATER TO DISSOLVE THE SODIUM TUNGSTATE, REMOVING ATHE INSOLUBLE RESIDUE FROM THE AQUEOUS LEACH LIQUOR BY FILTRATION, INTRODUCING AN ALKALI SULFIDE INTO THE LEACH LIQUOR IN A QUANTITY SUFFICIENT TO FORM A SOLUBLE SULFIDE COMPOUND WITH ANTIMONY OR ARSENIC COMPONENTS PRESENT IN THE LEACH LIQUOR, ACIDIFYING THE LEACHED LIQUOR WITH SULFURIC ACID AFTER SULFIDE INTRODUCTION TO ESTABLISH A PH BETWEEN 5 AND 7, SEPARATING THE IMPURITIES FROM THE ACIDIFIED LEACH LIQUOR BY FILTRATION, ADDING FLUORINE IN THE FORM OF A SOLUBLE FLUORINE SALT OR HYDROFLUORIC ACID TO THE LIQUOR IN A QUANTITY TO GIVE AT LEAST 6 MOLECULES OF FLUORINE FOR EVERY MOLECULE OF SILICA AND PHOSPHOROUS CONTAINED IN THE SOLUTION SAID LIQUOR BEING ACIDIFIED TO A PH LESS THAN 4 BEFORE FLUORINE INTRODUCTION, EXTRACTING THE ANIONIC TUNGSTEN COMPONENT OF THE FLUORINE TREATED ACIDIC SOLUTION WITH A WATER-INSOLUBLE REAGENT SELECTED FROM THE GROUP CONSISTING OF TERTIARY TRIDECYL, TRIAMYL, TRIISOOCTYL AND TRILAURYL AMINES IN A DILUENT SELECTED FROM THE GROUP CONSISTING OF KETONES AND KEROSENE WHILE THE CATIONIC SODIUM COMPONENT REMAINS IN THE AQUEOUS SOLUTION, STRIPPING THE ORGANIC EXTRACTANT CONTAINING TUNGSTEN WITH A DILUTE AMMONIUM HYDROXIDE SOLUTION HAVING AN EXCESS OF AMMONIA TO ESTABLISH A PH OF AT LEAST 7.5, CLAYRIFYING THE AMMONIUM HYDROXIDE SOLUTION CONTAINING THE EXTRACTED TUNGSTEN BY FILTRATION, SUBJECTING THE CLARIFIED SOLUTION TO EVAPORATION TO EXPEL MOST OF THE WATER AND CONTAINED AMMONIA AND PRECIPITATE CRYSTALLINE AMMONIUM PARATUNGSTATE, AND DISCHARGING DRIED AMMONIUM PARATUNGSTATE CRYSTALS AS A FINAL PRODUCT OF THE TREATMENT.