Guangsheng Huo

Separation of macro amounts of tungsten and molybdenum by ion exchange with D309 resin

Abstract Based on the difference in tendency to polymerize between tungsten and molybdenum, a new method using D309 resin was propounded. The batch tests indicate that the optimum pH value and contact time for the separation are 7.0 and 4 h respectively, the maxium separation factor of W and Mo is 9.29. And the experimental resules show that isothermal absorbing tungsten and molybdenum belongs to Langmuir model and Freundlich model respectively, and the absorbing kinetics for tungsten is controlled by intra-particle diffusion. With a solution containing 70 g/L WO3 and 28.97 g/L Mo, the effluent with a mass ratio of Mo to WO3 of 76 and the eluate with a mass ratio of WO3 to Mo of 53.33 are obtained after column test.

Thermodynamics and kinetics of adsorption of molybdenum blue with D301 ion exchange resin

Abstract The adsorption behavior of D301 for molybdenum blue was investigated. The thermodynamics parameters in adsorption process were calculated and the adsorption kinetics was studied. The experimental results show that the adsorption characteristic of D301 for molybdenum blue fits well with the Freundlich adsorption isotherm equation. In the adsorption process of D301 for molybdenum blue, both the enthalpy change Δ H and entropy change Δ S are positive, while the free energy change Δ G is negative when temperatures are in the range of 303-333 K. It is indicated that the adsorption is a spontaneous and endothermic process, and the elevated temperatures benefit to the adsorption. Kinetic studies show that the kinetic data are well described by double driving-force model, and the adsorption rate of molybdenum blue on D301 is controlled by the intraparticle diffusion during the adsorption process. The total kinetic equation is determined.

Influence of earth gravity on reaction engineering of tubular reactor for high concentration tungsten ion-exchange

The influence of gravity on the reaction engineering of tubular reactor is studied by analyzing the residence time distribution curves. The results show that upflow-feeding mode is more beneficial compared with downflow-feeding mode, since the flow pattern of the fluid in the reactor is closer to plug flow. The result of dynamic experiment conducted in ion-exchange of tungsten metallurgy is as good as that in reaction engineering of ion-exchange column. Whether downflow-feeding or upflow-feeding mode is adopted, breakthrough time decreases when solution concentration increases. Upflow-feeding mode has longer breakthrough time and greater improvement in adsorption capacity especially with high WO3 concentration in ion-exchange.

Removal of tungsten and vanadium from molybdate solutions using ion exchange resin

Abstract The removal of tungsten (W) and vanadium (V) from molybdate solutions was studied using the poly hydroxyl chelating resin D403 in batch and column experiments. The batch experiments indicated that tungsten and vanadium could be preferentially adsorbed by the D403 resin for 4 h in molybdate solution at a pH of approximately 9.25. Separation factors, αMoV and αMoW, were above 45 and 18, respectively, when the molar ratios of Mo/V and Mo/W in the solution exceeded 40. Elution tests illustrated that vanadium and tungsten could be easily eluted from the resin with 1 mol/L sodium hydroxide solution in only 1 h. To further explore the sorption mechanism of the resin, the experimental equilibrium isotherm data of the three metals fitted well with the Freundlich model. The column experiments confirmed the adaptability of the D403 resin in the production of sodium molybdate with a removal rate of tungsten surpassing 90% and that of vanadium of 99.4%.