Extraction of molybdenum from high-impurity ferromolybdenum by roasting with Na2CO3 and CaO and leaching with water

The extraction of molybdenum from high-impurity ferromolybdenum by roasting with Na2CO3 and CaO and leaching with water was studied. The results indicated that the process was an effective method to extract molybdenum from high-impurity ferromolybdenum. Under the optimum experimental conditions (CaO/Na2CO3 mole ratio of 0.76; Na2CO3 and CaO added total mole number of 0.57/100 g ferromolybdenum powder; oxidation roasting at 700 °C for 2 h; water leaching for 2 h at 98 °C with liquid/solid ratio of 3:1), the extraction of molybdenum was 97.5%, and the leached rate of impurities phosphorus, arsenic and silicon were only 16.2%, 18.1% and 41.2% respectively. The addition of CaO can effectively hold back the dissolution of the impurities in the leaching, which is due to the formation of Ca3(PO4)2, Ca3(AsO4)2 and CaSiO3.