Acidic Precipitation of Vanadium from High Concentration of Vanadium Solution by Ammonium Salt

Currently,the vanadium solution used for vanadium extraction,coming from the integrate process of sodium roasting and then water leaching of vanadium slag,has relatively lower vanadium concentration.It will produce a large amount of toxic waste water containing V⁵⁺,Cr⁶⁺,NH₄⁺,SO₄^2- and Na⁺ etc,which increases the cost of post-treatment and the risk of environmental pollution.In this paper,the feasibility of acidic precipitation of vanadium from high concentration of vanadium solution by ammonium salt was studied using ordinary vanadium solution with the concentration of vanadium increased as raw material.And the effects of ammonium addition coefficient(K),acid addition for the first time(pH₁),vanadium precipitation temperature(T),and acid addition for the second time(pH₂) on the recovery rate of vanadium and products grade were investigated.Moreover,XRF and ICP were used to analyze the vanadium concentration in solutions before and after vanadium extraction,grade and impurities content of products.The results show that the preparation of vanadium pentoxide from high concentration of vanadium solution is feasible.The optimum recovery rate of vanadium up to 99.83% can be obtained at 60 g/L of vanadium concentration,K=2,pH₁=5.0,T=90℃ and pH₂=2.0,with V₂O₅ purity of 99.99% which meets the standard of YB/T5304-2011.This study also provides a research basis for the industrial treatment of vanadium solution with low pollution and high efficiency.