TUNGSTEN RECOVERY FROM SULFIDE-CONTAINING W-TAILINGS: Beneficiation Tests and Bioleaching for Sulphide Removal

Overview & Synopsis

In the frame of the H2020 RAWMINA project (Grant Agreement nº 958252), recovery of critical raw materials such as tungsten (W) in mining waste is evaluated by various innovative (bio)hydrometallurgy techniques. First, the recovery of W from sulfidic mining waste is carried out by applying gravimetric separation techniques to concentrate W-bearing minerals (mainly sheelite). W can then be leached from the beneficiated tailings using alkaline leaching. However, arsenic-containing sulfides, such as arsenopyrite, can also be significantly deported in the W concentrate which can cause an increase of the reagents consumption in the alkaline leaching process (Suess and Planer-Friedrich, 2012). Moreover, the presence of As in the concentrate could negatively impact downstream processes and the final products. Bioleaching is known to be efficient in the removal of sulfidic material even at low sulfide content (Hubau et al., 2020). Therefore, after the beneficiation process, bioleaching is used to treat sulfide and reduce acidity, iron and arsenic concentrations in the beneficiated material.