Process of recovering tungstic oxide substantially free of molybdenum compounds

Claim 1

THE PROCESS OF RECOVERING TUNGSTIC OXIDE OF HIGH PURITY SUBSTANTIALLY FREE OF A MOLYBDENUM COMPONENT AND OTHER CONTAMINANTS FROM A MINERAL MATERIAL CONTAINING A TUNGSTEN COMPOUND AND OTHER MINERAL CONSTITUENTS INCLUDING A MOLYBDENUM COMPOUND ISOMORPHIC WITH SAID TUGSTEN COMPOUND,COMPRISING DECOMPOSING SAID MATERIAL WITH AT LEAST APPROXIMATELY 20CC.''S BY VOLUME OF CONCENTRATED HYDROCHLORIC ACID FOR EACH GRAM OF TUNGSTEN PRESENT EXPESSED AS TUNGSTIC OXIDE, WO3, SAID HYDROCHLORIC ACID SOLUTION BEING MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 60* C. AND BELOW 70* C., THE TUNGSTEN AND MOLYBDENUM COMPOUNDS BEING SUBSTANTIALLY COMPLETELY MAINTAINED IN SOLUTION DURING TREATMENT PERIOD TOGETHER WITH ANY ACID SOLUBLE IMPURITIES DERIVED FROM THE MATERIAL TREATED, THE HYDROCHLORIC ACID SOLUTION BEING MAINTAINED DURING THE TREATMENT PERIOD IN ITS CONCENTRATED STATE, SEPARATING THE RESULTING SOLUTION CONTAINING THE TUNGSTEN COMPOUND AND THE MOLYBDENUM COMPOUND, AND ANY ACID-SOLUBLE IMPURITIES, HEATING THE SEPARATED CONCENTRATED HYDROCHLORIC ACID SOLUTION CONTAINING TUNGSTEN AND MOLYBDENUM COMPOUNDS ABOVE TEMPERATURE OF 70* C. AND THEREBY PRECIPITATING THE TUNGSTEN-CONTENT OF SAID SOLUTION AS ACID-INSOLUBLE YELLOW TUNGSTIC OXIDE WHILE KEEPING THE MOLYBDENUM COMPOUND AND ANY IMPURITIES IN SOLUTION, AND RECOVERING THE PRECIPITATED TUNGSTIC OXIDE FROM THE SO-TREATED SOLUTION.