Study On Recovery Of Vanadium From Low-grade Vanadium Slag Containing High Calcium Content

Vanadium is an important industrial material,but the resources for reasonable extraction of Vanadium are limited.Besides the Vanadium occurs mainly in compl ex multi-Ore,and its belongs to low grade ore,mostly below 1%.The main raw materials for the production of vanadium containing vanadium steel slag,coal,bauxite and other waste catalyst.A novel process of extracting vanadium from vanadium-containing deposition residue which came from a factory of Guangxi Province was proposed in this paper.The vanadium slag with a feature that it a low-grade vanadium slag containing high calcium content.Then,this paper puts forward a novel process of addition of basic additives roasting and ultrasonic assisted sodium carbonate leaching process,and on this basis proposed the leach solution using quaternary ammonium carbonate-type extraction separation of vanadium and aluminum,sodium hydroxide together with sodium carbonate for stripping,and Ammonium metavanadate is obtained after precipitating vanadium from ammonium salt,which will turn to V₂O₅ after burning.Extracting vanadium from vanadium slags roasting with additive and leaching was studied.The effects of additives and additives,roasting temperature and roasting time on the leaching of vanadium slag were investigated at first.The results showed that the optimum roasting process parameters were as follows :the addition of sodium hydroxide at 35% the amount of vanadium slags,roasting under 1223 K for 8h.On this foundation,the impact of related factors on vanadium leaching roasting leaching process were investigated.Research has shown that the optimum leaching conditions of roasting slag under the condition of sodium carbonate solution?concentration is 2.0 mol / L?as leaching agent,liquid to solid ratio was 5:1 mL / g,60? for the teperature,under 180 W ultrasonic irradiation 60 min,leaching rate of vanadium slag exceeds 90%.In order to concentrate the vanadium and remove the aluminum from the leaching solution of vanadium slag,the quaternary ammonium extraction system was established in the paper.The effect of the quaternary ammonium concentration,modifier concentration,pH of the solution,phase ratio,extraction temperature and the oscillation time on the separation of vanadium and aluminum were investigated.Experimental results show that the organic portions of 40% extraction system carbonated A336 + 16% DL-2-Octanol + 44% octanol sulfonated kerosene can feed solution?V₂O₅ = 0.9 g / L,Al₂O₃ = 4.3 g / L,pH = 13.9?in the extraction separation of vanadium and aluminum,the optimum extraction conditions were as follows: the phase ratio is 1:1,the temperature is 25 ?,the oscillation frequency of 220 rpm,the oscillation time of 10 min.Vanadium single-stage extraction rate of more than 80% and the separation factors of vanadium and aluminum reached 37.By drawing extraction isotherm,It turned out that when the O / A is 1/2,the other conditions remain unchanged,the three countercurrent extraction,the vanadium extraction ratio comes up to 99%.This study adopts the process impurity washed with sodium carbonate solution?concentration 10 g / L?to remove 92% of the aluminate of loaded organic phase.By orthogonal experiment established the optimum stripping process parameters:the Na₂CO₃ concentration is 1.8 mol / L and Na OH concentration is 1.0 mol / L,phase ratio is 1:1,a temperature of 45 ?.Under these parameters,the stripping rate of vanadium can be more than 80%.By the 4 stage countercurrent stripping,the vanadium concentration in the organic phase was reduced to 0.05 g / L or less.The vanadium precipitation process were studied in the solution purified.The effeets of molar ratio of ammonium salt to vanadate,the initial concentration of vanadium,PH,reaction temperature,agitating rate and time,and aging time on the vanadium precipitation process were investigated.The results showed that the optimum conditions of vanadium precipitation were as follows: plus ammonium coefficient of 6.0,agitating 1 hour with stirring speed 350 r / min and aging 45 min,temperature was 80 ?,at pH 8.5.Then the crystal Ammoniummeta vanadate was washed,thought drying and roasting,the red powdery product was obtained.By chemical analysis,the quality of V₂O₅ accords with national level 99 metallurgical quality.