电场强化石煤浸出提钒试验研究

Experimental Study on Vanadium Extraction from Stone Coal Enhanced by Electric Field

为探究电场对石煤浸出提钒的强化作用,以陕西某石煤钒矿为研究对象,硫酸为酸浸剂,开展了酸浸提钒的条件试验,在此基础上,考察电场对焙烧前后试样浸出效果的影响,并通过浸出液开路电位和循环伏安曲线测试分析强化机理。在硫酸浓度20%、浸出温度90℃、浸出时间4 h、液固比7∶1的条件下,石煤原矿钒浸出率为62.50%,施加电场强度1 000 mA时,钒浸出率提高至67.32%。对于600℃焙烧3 h的焙烧样,未施加电场时钒浸出率为68.96%,施加电场强度1 000 mA时,钒浸出率提高至71.31%。施加电场后,浸出液由浅绿色变为蓝色,钒被氧化为更高价态。机理研究结果表明,浸出液中存在VO2+、VO2+不同价态的钒离子,浸出体系中VO2+在电场作用下被还原,出现2对不同的氧化还原特征峰。

In order to explore the electric field reinforcement on the vanadium leaching extraction from stone coal,the condition tests were conducted regarding vanadium-contained stone coal in Shaanxi province as the research object,sulfuric acid as acid infusions. The electric field intensity on the leaching effection were investigated for the samples before and after roasting,and strengthening mechanism were analyzed through the open circuit potential and cycle volt-ampere curve test for the leaching liquid. Under the conditions of sulfuric acid concentration of 20%,leaching temperature of 90 ℃,leaching time of 4 h and liquid-solid ratio of 7∶1,the leaching rate of vanadium from raw stone coal was 62.50%,and the leaching rate increased to 67.32% when the electric field was applied at 1 000 mA. For the roasted samples roasted at 600 ℃ for 3 h,the leaching rate of vanadium was 68.96% without the application of electric field,and increased to 71.31% when the electric field was applied at 1 000 mA. After the electric field is applied,the leaching solution changes from light green to blue,and the vanadium is oxidized to a higher valence state. The results of mechanism study showed that there were vanadium ions with different valence states of VO2+and VO2+in the leach solution,and VO2+was reduced in the leaching system under the action of electric field,and two pairs of REDOX characteristic peaks appeared.