Experimental Study on Recovery of Vanadium from Low-grade Vanadium Slag Containing High Calcium Content

A laboratory test was carried out to prepare V₂O₅ from low-grade vanadium slag containing high calcium content by salt roasting-water leaching processes.By using the methods of single roasting and mixed roasting with ordinary vanadium slag,the technologies and relevant parameters were obtained for V₂O₅ preparation from the above-mentioned vanadium slag.The results show that the method of mixed roasting with ordinary vanadium slag is better than single roasting.The best results can be achieved in mixed roasting with the soaking time of 2.5 hours,the mass ratio of soda to salt of 100:15,the mass ratio of ordinary vanadium slag to low-grade vanadium slag of high calcium to tailings of 50:30:20,and the temperature of 800℃.Under the conditions,the leaching ratio reaches 85% or above.The V₂O₅ finished products prepared from leaching solution after dephosphorization,vanadium precipitation and roasting meet the standards of YB/T 5304 -2011.