Abstract: Using the vanadium containing solution，obtained from leaching sodium roasted vanadium slag clinker，as the raw material，the removal mechanisms of CaSO4·2H2O on the phosphorus in vanadium containing solution under the alkaline condition were analyzed.The effects of CaSO4·2H2O dosage，pH of solution，reaction time and reaction temperature on the removal efficiency of phosphorus，loss rate of vanadium and mass concentration ratio of V2O5 to P were studied．Results showed that phosphorus can be effectively removed from the vanadium containing solution under weak alkaline condition by using CaSO4·2H2O.The removal efficiency of phosphorus was higher than 70%，the loss rate of vanadium was lower than 1%，and the mass concentration ratio of V2O5 to P was higher than 2 300，which satisfied the requirements for the subsequent vanadi umprecipitation process.The optimum operation conditions for removing phosphorus were confirmed as follows：n（CaSO4· 2H2O）/n（P）=5.3，pH of solution was 9.0，reaction time was 30 min and reaction temperature was 25 ℃.Vanadium pentoxide was obtained from the phosphorus removed vanadium containing solution by vanadium precipitation，washing and calcinations.The yield of the vanadium precipitation process achieved as high as 99%，and the product quality satisfied the Level 99 requirements for the standard of Vanadium Pentoxide （YB/T 5304—2011）.

Key words: vanadiumcontaining solution；phosphorus removal；CaSO4·2H2O；vanadium pentoxide