Separation of Vanadium and Molybdenum ions in Blue Sludge leachate by Ion Exchange Resin

• Main Authors: Min-ChienHu, 胡閔茜
• Other Authors: Yun-Hwei Shen
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/23423413110947350152

碩士 === 國立成功大學 === 資源工程學系碩博士班 === 101 === At present, the annual production of wasted hydrodesulfurization catalyst domestically is about 11,000 tonnes. The residues obtained by extracting V and Mo from wasted hydrodesulfurization catalyst is called the blue sludge. In order to further recover V, Mo and Ni, the blue sludge was subjected to acid-roasting and hot-water leaching process. This process yields an leachate rich in Ni and Al and also containing some V and Mol ions. The subject of this research is the leachate from blue sludge. In this study we investigate the recovery and separation of V and Mo ions in leachate by ion exchange process. Batch experimental results indicated that both chelating resin；referred to as resin M and I；adsorb V and Mo effectively. The effects of contact time, pH and temperature on ion exchange behavior of two metal ions was studied. The adsorption isotherms were described by means of Langmuir and Freundlich models. Langmuir isotherm model showed that resin M adsorbs more V and Mo than I. Freundlich isotherm model indicated that the adsorption capacity of V is insenstive to the change in the equilibrium concentration of solute. However the adsorption capacity of Mo is influenced by the change in the equilibrium concentration of solute. The kinetic data were tested using the Lagergren-first-order and pseudo-second-order kinetic models. Data for Ion exchange of V and Mo correlated well with the pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. The activation energy for the exchange of V and Mo on resin I and M is 36.92、6.16、38.02、0.75 kJ mole-1 respectively. Various thermodynamic parameters for exchange reactions between I、M and V、Mo such as Gibbs free energy change ( G0), enthalpy change( H0) and entropy change( S0) were calculated. A negative G0 indicated that the ion exchange of V and Mo from solution using I was feasible. Results of batch desorption tests show that V ions on resin M and I were succesfully desorbed by using H2SO4 and NaOH respectively. Mo ions on resin M and I were succesfully desorbed by using NH4OH and NaOH respectively. The results of column tests indicated that the slower the flow rate of feed solution the better the adsorption of V and Mo. Maintaining the pH of leachate at 2, resin I has the highest adsorption capacity for V and Mo. Resin I adsords ions in the following order: Mo〉 V〉〉 Ni〉 Al. Having operated for 140B.V in adsorption mode, the loaded resin I can be successfully eluted. Finally, a V concentrate with 1200ppm peak concentration and 87.3 purity and a Mo concentrate with 1800ppm peak concentration and 99.1 purity were obtained.