The Fundamental Study Of Vanadium, Phosphorus And Silicon Separation On D201 Ion Exchange Resin

Vanadium is a kind of rare and high melting point metal which can be dissolved in sour or alkali solution. In lixivium, vanadium is the form of vanadium radical which can be adsorbed and exchanged by the anion group in the resin and be separated with impurities. The paper was studied the adsorption behavior and mechanism of D201 resin for vanadium (V), phosphorus, silicon. Main conclusions were obtained as following:In singular element system, effects of pH, resin amount, temperature and time on adsorption behavior were investigated. The best adsorption effect on vanadium could be obtained when pH was 1.9-2.1, since it's related with the condition of vanadium in solution. The best adsorption effect on phosphorus could be obtained when pH was 6.9-7.1 while silicon was pH11.4-11.6. The equilibrium time of vanadium was about 11h, phosphorus was 30min and silicon was 40min. Higher temperature were beneficial for the adsorption of vanadium and phosphorus while lower temperature was good for silicon.There was little effect of phosphorus or silicon on the adsorption of vanadium in multi element system. The separation coefficient of vanadium and phosphorus was 48.33 and the separation coefficient of vanadium and silicon was 106.77 when pH was 1.9-2.1.The results of the column dynamic adsorption experiments showed that the flow rate should be lower than 2BV/h. The suitable conditions for the desorption were 5%NaOH+10%NaCl as the eluent and 2-3BV/h flow rate.Langmuir and Freundlich isotherms were both suitable for describing the adsorption process. The thermodynamic study showed that the adsorption of vanadium, phosphorus and silicon was spontaneous and the entropy was positive. The adsorption of vanadium, phosphorus was endothermal but silicon was exothermic.A sencond-order adsorption-ion exchange kinetic equation was developed for the process, and the equation parameters were estimated, results indicated that the adsorption of vanadium and phosphorus were controlled by the diffusion through micro ball of macroporous resin and silicon was controlled by the diffusion through micro ball and macropore of macroporous resin.