Recovery of vanadium, potassium and iron from a spent catalyst using urea solution

A spent vanadium catalyst was leached in a urea solution to recover vanadium, potassium and iron. The effect of time, temperature, pH, concentration of urea, phase ratio and catalyst particle size was studied. Results showed that for 180–250 μm catalyst leached for 1 h at 20 °C in the presence of 40% urea solution at a liquid:solid ratio of 10:1, the extent of leaching of V, K and Fe were about 78%, 90% and 29% respectively. A flowsheet for the proposed process is presented.