Experimental Study On Sodium Removal From Sodium Vanadium

The tailings from converter vanadium recover process treated by oxidizing roasting with NaCl and leaching is termed as the extracted vanadium residue.China has a high yield of vanadium per year, which causes a huge amount of the extracted vanadium residue. These tailings are generally preserved in the tailings dam due to its low value, leading to the waste of land as well as vanadium resources. The recycling of vanadium tailing has attracted much attention and the researches are focused on the vanadium recover from the extracted vanadium residue, other valuable metals extraction and ceramic materials development, etc. However, there is yet no complete set of clean process with high efficiency which, in the meanwhile, could bring a large consumption of the vanadium tailings.The extracted vanadium residue as raw materials was taken from a steelworks. Methods of alkali leaching, reduction roasting and magnetic separation were taken to remove sodium from the extracted vanadium residue. After these treatment, the sodium content in the tailings was lowered to ensure their reuse in the blast furnace while avoiding influencing the basicity of the furnace. In this case, the tailings could be maximized recycled.The main conclusions and results are as follows.1.The results of lithofacies and chemical composition analysis of the extracted vanadium tailings indicate the main phase are pyroxene solid solution, iron oxide and silicate. Sodium and vanadium mainly exists in the pyroxene solid solution and some are scattered in the silicate phase.2.Calcium oxide and magnesium oxide were selected as the final sodium removal agent from several reagents by experiments.3.To lixiviate sodium from the extracted vanadium tailings, hydrothermal method by adding calcium oxide under the conditions of normal pressure or raising pressure was used. The effects of particle size, reagent dosage, temperature, reaction time and leaching agent on the sodium removal efficiency were analyzed respectively. The optimal parameters of this sodium removal process by calcium oxide were achieved. The result shows that the highest sodium removal rate of 80.5% can be reached under the condition of 200℃,14% CaO and 1hour.4. During the procedure of leaching sodium from the extracted vanadium residue by adding magnesium oxide under the condition of normal pressure or raising pressure, most of the vanadium was leached out simultaneously in the process. The effects of particle size, reagent dosage, temperature, reaction time and leaching agent on the sodium removal efficiency and vanadium leaching productivity were studied., The optimal parameters of vanadium leaching and sodium removal by magnesium oxide processes were achieved. The result shows that the highest sodium removal rate of 47.67% and the vanadium leaching rate of 66.26% can be reached under the condition of 180℃、8% MgO and 2 hour.5.The extracted vanadium residue mixed with coal dust was reduction roasted in high temperature. The reduction product was separated by magnetic separation. The effects of carbon content, calcination time, calcination temperature, magnetic field strength on the metallization rate of the extracted vanadium residue pellets and the efficiency of magnetic separation were investigated. The result shows that the sodium content in the magnetic concentrate drops to 1.9%, while TFe reaches 70% and the recovery rate of iron reaches 84.8% under the condition of 1200℃ and 1 hour.