of carbonate per mole of molybdenum present in the ore calculated as molybdenum disulfide any of the alkali metal carbonates such as sodium carbonate potassium carbonate lithium carbonate and the like can be used however sodium and potassium carbonates are preferred with sodium carbonate being especially preferred silica is present as an impurity in most ores the presence of excess carbonate will normally result in conversion during fusion of such silica impurities to water soluble form in accordance with the invention sufficient alumina is added to the fusion mix to combine with the contained silica to form insoluble compounds typically silicates such as aluminum silicate preferably al 2 o 3 in excess of the stoichiometric amount required is avoided since such excess tends to increase the temperature required for fusion however al 2 o 3 in amounts up to 50 in excess of the stoichiometric amount may be added the fusion temperatures are from about 700 u00b0 to 950 u00b0 c at temperatures below about 700 u00b0 c the fusion mass may solidify and since some of the materials may be evolved about 950 u00b0 c this temperature constitutes a practical upper limit after the ore and the alkali metal carbonates and the alumina are blended together and heated to the desired fusion temperature the temperature is maintained until the evolution of gases primarily carbon dioxide ceases after the evolution of gases ceases the molten fusion mass may be oxidized to form additional amounts of soluble compounds of molybdenum and rhenium lack of oxidation results in essentially all of the rhenium values and a portion of the molybdenum values normally about 5 percent remaining water insoluble such oxidation may be carried out on the still molten fusion mass in order to recover maximum amounts of molybdenum and rhenium values as.