石煤焙烧—加压酸浸提钒研究

为探索提高石煤中钒的浸出效率,以湖北通山某石煤矿石为研究对象,进行了石煤焙烧—加压酸浸提钒工艺研究。结果表明:在焙烧温度为850℃、焙烧时间为60 min、釜内压力为1.0 MPa、硫酸初始浓度为15%、液固比为1.5 m L/g、浸出温度为150℃、浸出时间为120 min条件下,钒浸出率可达80.51%。采用红外光谱法分析了加压浸出前后云母矿物的晶体结构,并从动力学的角度揭示了浸出温度对钒浸出的影响机理。结果表明:加压浸出可以破坏云母晶格,进而有利于释放云母晶格中的钒,提高钒浸出效果。浸出过程动力学分析结果表明:浸出温度对浸出过程影响显著,浸出温度为60~120℃时,表观活化能为41.603 k J/mol,浸出过程受化学反应控制;150~210℃时,表观活化能为4.319 k J/mol,浸出过程受内扩散控制;加压浸出能够将浸出温度提高至100℃以上,有效提高了硫酸破坏云母晶格的速率,是提高钒浸出效率的关键。

Study on Roasting-Pressure Acid Leaching of Vanadium from Stone Coal

In order to find a process which could increase the leaching velocity of vanadium，roasting-pressure acid leaching of vanadium on stone coal from Tongshan in Hubei was investigated.Results showed that，the optimal operation conditions are as followed:the roasting temperature was 850 ℃，the roasting time was 60 min，the kettle pressure was 1.0 MPa，initial concentration of sulfuric acid was 15%，ratio of liquid to solid was 1.5 mL/g，leaching temperature was 150 ℃ and leaching time was 120 min，with these conditions the vanadium leaching rate could reach 80.51%.The changes of mica mineral structure during leaching process were analyzed by Infrared Spectrometry analysis and the effect of temperature on vanadium efficiency was studied from the aspect of leaching kinetics.The results indicated that pressure acid leaching could destruct the crystal lattice of mica that was helpful for the release of vanadium and the increase of vanadium leaching efficiency.The leaching kinetics analysis results indicated that:effect of leaching temperature on vanadium efficiency was conspicuous，when the leaching temperature ranged from 60 to 120 ℃，the apparent activation energy was 41.603 kJ/mol and the leaching was controlled by surface chemical reaction.When the temperature ranged from 150 to 210 ℃，the apparent activation energy was 4.319 kJ/mol and the leaching was controlled by inner diffusion of reactants.As pressure acid leaching could raise the leaching temperature over 100 ℃，the destruction velocity of mica crystal lattice could be raised effectively and the vanadium leaching time could be shorten effectively.