The process of regenerating vanadium oxide from metal or carbon into vanadium is an important part of vanadium metallurgical process. The first four methods are calcium thermal recovery, vacuum thermal recovery, magnesium chloride thermal recovery and aluminum thermal recovery. Calcium thermal recovery a method of industrial planning for the production of metallic vanadium. V2O5 or V2O3 was used as material, and chips were used as recovery agent. The amount of calcium used is 60% of the theoretical amount. Fragmental and V2O5 or mixes V2O3, clean with inert gas to put in a steel reaction tank of magnesia crucible (PiaoChangLin), add iodine compound (sulfur), generation of iodine in quantity by 1 mol, vanadium increases 0.2 mol, iodine measurement, after argon filling sealing, heat with high frequency sensor, the temperature of 973 k when it start response: V2O5 + 5 + 5 ca material 2 v cao + 1620.07 kJ V2O3 + 3 ca material 2 v + 3 cao + 683.24 kJ because of exothermic reaction, response to start then stop after heating. The temperature will rise to 2173K after the heating is stopped. The generated plastic vanadium block or vanadium particles were washed away with water, and the yield of vanadium was about 74%. When aluminum is added to the charge, the yield of vanadium can be increased to 82% ~ 97.5%. Vacuum carbothermal recovery mix V2O5 powder and high purity carbon powder evenly, add 10% camphor solution or alcohol, press the block and put it into vacuum carbon retarder furnace or induction furnace. After the vacuum pressure in the furnace reached 6.66× 10-1pa, the temperature was raised to 1573K and the temperature was kept for 2h. The product will be crushed after cooling. According to the components of the first recovery product, an appropriate amount of vanadium carbide or vanadium oxide was added for the second recovery. The vacuum pressure in the secondary furnace is 2.66× 10-2pa, the temperature is controlled between 1973 and 2023K, and the temperature is kept for a period of time. The components (mass fraction m/%) of vanadium obtained by vacuum carbon recovery method are: vanadium 99.5, oxygen 0.05, nitrogen 0.01, carbon 0.1.
The yield of vanadium can reach 98% ~ 99%. Magnesium thermal recovery of the metal magnesium purity is high, the price is lower than calcium, reaction produced by magnesium chloride is more volatile than calcium chloride, so magnesium recovery is more reasonable than calcium recovery. The recovery process is as follows :(1) making crude by chlorination of ferric vanadium containing 80% vanadium; (2) removal of crude vanadium tetroxide by distillation; (3) it will be converted into VCl3 in a cylindrical magnesium reflux; (4) remove VOC13 in VCl3 by distillation; (5) the cooled and crushed parts were placed in the recovery tank, and the VCl3 was recovered into metallic vanadium by magnesium under argon maintenance; (6) remove magnesium and magnesium chloride from vanadium by vacuum distillation; (7) the residual magnesium chloride in vanadium was washed with water, and the product vanadium powder was obtained after boring.
