Production of high purity APT from scheelite and complex tungsten raw material with high Mo content

More than 73% of the tungsten resources in China are scheelite and 41% are high molybdenum content ores, and their dressing becomes increasingly difficult. Such situation calls for new and advanced processes that can treat complex ores and still attain high overall recovery of tungsten. The novel NaOH digestion process and selective precipitation process was developed. The former is universal for leaching tungsten from various tungsten materials,including scheelite concentrate and keeps most of the impurity elements P, As and Si in residue; while the latter is effective for removing impurities such as Mo and Sn. Combined with the traditional ion exchange process, the new process can be used to produce APT that confirms with the Chinese National Standard GB10116-88APT-0 with crystallization ratio of 95 %. When treating high molybdenum scheelite concentrate from Shizhuyuan Deposit with WO3content of 50%- 55%, recovery of the new process may reach up to about 95% which is grossly the same as that from the traditional way for treating standard wolframite concentrates.