Vanadium: The Canadian Petrofina Plant

One example of an industrial plant which pioneered the production of vanadium from oil fly ash was the Canadian Petrofina plant in Quebec which operated during the 1960's and 1970's [Whigham, 1965]. Ash from the steam boilers routinely contained greater than 15% V2O5; subsequent research led to the development of the flowsheet shown in Figure 1.6. In this process, ash is leached with sulfuric acid at pH 0.2 and 90°C. The vanadium in the filtered leach solution is oxidized to V+5 using sodium chlorate and the vanadium is then precipitated as red cake by adding ammonia to the solution to raise the pH to about 2. Extractions and precipitation efficiencies of about 95% gave an overall vanadium recovery of 90 %. Whigham had not give the iron