Separation of tungsten and molybdenum using macroporous resin: Equilibrium adsorption for single and binary systems

• A new method using macroporous resin for separating W and Mo is presented.
• The affinity of W towards the macroporous resin is higher than that of Mo at pH = 7.25.
• The macroporous resin exhibits a large adsorption capacity for W polyions.
• Multi-component models are used to analyze the binary adsorptive behavior.
• The proposed method can effectively separate W and Mo from the mixed solution.

Tungsten and molybdenum are widely used in many hi-tech industrial products, but it is a challenge to separate them from the resources containing high contents of the two metals. Based on the difference in tendency to polymerize between W and Mo, a new method using macroporous weak base resin was developed to separate W and Mo. The feasibility of this method was evaluated in this work, particularly. The effect of pH and contact time was studied on the adsorption of W and Mo using macroporous weak base resin D301. In addition, the equilibrium adsorption of W and Mo was investigated at the optimal pH-value in both individual and binary systems. Several single-component and multi-component isotherm models were used to analyze the experimental adsorption data, with which the values of parameters were obtained accordingly. The Freundlich model and the extended Freundlich model were successfully applied to describe the adsorptive behavior of W and Mo in the single and binary system, respectively. Tungsten and molybdenum in the binary adsorption system are interacting with each other in an antagonistic manner and the former exhibits stronger competitive ability. As a result, the equilibrium adsorption amount of W is much higher than that of Mo in the mixed solution. Obviously, the proposed method can effectively separate W and Mo from the mixed solution, and it may have a very promising future in industry.