Research on Impurities Removal from Alkaline Solution Containing Vanadium and Chromium

Using the alkaline V-Cr solution obtained from sodium roasting of V-Cr slag as raw material,the contents of main elements like V and Cr,impurities such as Si and P in the solution were analyzed.The removal mechanisms of Si and P using aluminum salt in alkaline solution were discussed.The effects of Al₂(dosage,pH value,reaction temperature and time,and rest time on the removal efficiency of Si and P were studied.The results show that 98%of Si and 92%of P can be effectively removed from the V-Cr solution using aluminum salt at low basic conditions,which satisfies requirements for the subsequent vanadium precipitation.The optimum test conditions are as follows:Al∶Si（molar ratio）=1.2,pH=9.0,90℃of temperature,15 min of reaction time,and 1 h of aging time.The loss of V and Cr are less than 5%in the purification process.Moreover,V and Cr in the slag of impurities removal can be easily washed and recycled.Through precipitation of the purified liquor and subsequent calcination of the precipitate,powdered product containing more than 99%ofthe standard requirements of YB/T5304—2011,can be obtained with precipitation rate of vanadium over 98%.