Preparation of Sodium Tungstate from Waste Catalyst Containing Tungsten and Nickel

Sodium tungstate was prepared by roasting plus sodium-leaching-ion exchange and with waste tungsten-nickel hydrogenation catalyst as the raw material.

The results show that the tungstate leaching rate from waste catalyst can reach 99% when the catalyst grinding size is 0.15 mm,the ratio of Na₂CO₃ dosage to WO₃ dosage 0.69,leaching temperature 90 ℃,and leaching time 1 h. The saturation ion-exchange capacity of WO₃ is 332.9 gWO₃/L-dry resin with the method of serial column absorption. The WO₃ desorption rate is 98.2% with 2 mol/L NaCl and 1 mol/L NaOH mixture solution as the desorption agent. The purity of sodium tungstate is 99% after recrystallization.