Study on Quality Improvement of Vanadium Precipitation with （NH₄）₂SO₄

The optimization of process parameters and control measures during the process of vanadium precipitation with acidic ammonium is studied to improve the quality of feedstocks for the production of high grade V₂O₃.Major factors contributing to the quality of APV prepared by vanadium precipitation with acidic ammonium are investigated,such as concentration of vanadate leaching solution,adding amount of ammonium salt,temperature of vanadium precipitation,reaction time,pH value,stirring conditions and washing condition of the plate and frame filter press.The results indicate that impurities in the precipitated APV can be reduced with the concentration of vanadate leaching solution at 25 to 35 g/L,two-step acid adding process,final precipitating temperature of 95 ℃,reaction time of about 35 min,washing time of filter cake for 20 min,temperature of washing water at about 75 ℃,the blowing time during pressing for 80 min,wind pressure of no less than 0.5 MPa,and cake thickness of no more than 25 mm etc.