【作者】 高峰；

【导师】 颜文斌；

【作者基本信息】 吉首大学 ， 应用化学， 2011， 硕士

【摘要】 参考前人的研究结果,以湖南湘西古丈县的含钒石煤为原料,针对传统钠法焙烧提钒工艺转浸率不高、环境污染严重、资源利用率低等不足,提出复盐焙烧—低酸浸出—离子交换—铵盐沉钒的工艺路线,通过对石煤提钒焙烧过程的系统研究及对提钒离子交换过程、铵盐沉钒过程中相关理论的探讨。大大提高了含钒石煤提钒的收率,改善了焙烧法（火法）提钒的环境污染问题,为石煤提钒行业提出了适宜的工艺参数。主要研究内容和结果如下:实验分析了湘西古丈石煤的成分,着重对石煤矿石复盐焙烧、低酸浸出、离子交换富集钒及铵盐沉钒过程进行了研究,其中包括复盐种类、复盐配比、复盐用量、焙烧时间、焙烧温度及浸出液固比、浸出硫酸用量、浸出温度、浸出时间对钒浸出率的影响,设计了正交试验方案,进行了正交试验;考察了D201树脂吸附钒（ⅴ）的性能及其静态吸附机理,同时探讨D201树脂吸附钒的动力学过程;探索了在弱碱性条件下,偏钒酸根的初始浓度、加铵系数K、pH值、温度等因素对沉钒率的影响,在适合组合条件下进行沉淀析出的动力学研究,用积分法建立数学模型,以确定沉钒过程动力学的相关参数;并通过X射线衍射和红外光谱分析,对沉淀产物进行了表征;按照HG/T 3445-2003分析偏钒酸铵及五氧化二钒的纯度。实验表明:石煤样品测试显示,该矿含五氧化二钒为0.85%,含二氧化硅高达75%,样品中的钒主要存在钒云母相中,属难分解含钒矿物。焙烧实验表明,采用氯化钠、碳酸钠和硫酸钠组成的复合盐体系较传统工艺大大降低了氯化钠的用量,减少焙烧尾气对环境的压力,钒的浸出率又能显著提高,钒的浸出率受复盐用量、复盐配比、焙烧温度、焙烧时间、浸出酸用量的影响,较佳的工艺参数为:焙烧温度为750℃,复盐添加剂用量为9%,焙烧时间为2h,浸出温度50℃,加酸量2%,浸出时间4h;在此条件下,钒的浸出率可达95%以上。采用D201树脂分离富集钒,在温度为303K,pH值为2.0,五氧化二钒浓度为12g·L^-1条件下,D201树脂吸附钒饱和吸附容量为306mg·g^-1;钒溶液流速为0.02mL·min^-1·g^-1时,动态平衡吸附量为270mg·g^-1。实验表明D201树脂对钒的吸附符合Freundlish等温吸附模型,对钒吸附交换过程符合拟二级吸附交换动力学过程;反应级数为拟二级,吸附速率随温度升高而增大,反应活化能为14.165KJ·moL^-1;钒在D201树脂上的吸附过程的控制步骤为粒扩散过程。洗脱液氯化铵沉钒过程较适合的沉钒条件是:pH=8.0,加铵系数2,温度50℃,钒溶液浓度30g·L^-1,沉钒率可达99%以上;对氯化铵沉钒过程的动力学研究表明,用微分法推导出了氯化铵沉钒过程的动力学数据,反应级数n=2、动力学常数为0.6×10^-3(mol·dm^-3)^-1·min^-1,偏钒酸铵制备是二级反应反应速率方程是r=0.6×10-3（a-x）（b-x）;沉淀产品的红外光谱图与偏钒酸铵标准图谱一致;经XRD分析产品结构单一,晶体纯度较高;偏钒酸铵经煅烧得V₂O₅产品,产品经检验质量指标均达到了HG/T 3445-2003化工用粉钒标准;研究结果可给含钒石煤复盐焙烧提钒的工业化提供参考。更多还原

【Abstract】 The stone coal from Xiangxi Guzhang County as raw material, the process of composite salt roast to extract vanadium was systematically studied. The related theories of ion exchange process and depositing vanadium with ammonium were investigated. The main processes were determined as composite salt roast—low acidity H2SO4 leaching—ion exchange—depositing vanadium with ammonium. Main work and results are as follows:The compositions of stone coal from Xiangxi Guzhang County were analyzed. The content of vanadium pentoxide is about 0.85%, silica reached to 75% in stone coal sample, which is almost completely to located or implanted inside vanadic mica, belonged to difficult decomposition containing vanadium minerals. Compared with traditional technology, composite salt technology system including sodium chloride, sodium carbonate and sodium sulfate, greatly reduced the sodium dosage, settled the problems of environment pollution, and the leaching rate of vanadium increased significantly. Effect of the additive of composite salt, composite salt ratio, roast temperature, roast time, the dosage of sulfuric acid on vanadium leaching rate were investigated. Roast temperature 750℃, composite salt dosage 9%, roast time 2h, leaching temperature 50℃, leaching time 4h, and acid dosage 2%, the vanadium leaching rate is higher than 95% under this condition.Enriching the vanadium with D201 exchange resin, saturated adsorption capacity of D201 exchange resin is 306mg·g^-1 with the optimum conditions involving temperature 303K, pH 2.0 and the vanadium pentoxide concentration of 12g·L^-1. With the vanadium solution velocity of flow at 0.02mL·min^-1·g^-1, dynamic equilibrium adsorption capacity was 270mg·g^-1. Results exhibited that the D201 resin adsorption process for vanadium corresponded with Freundlish isothermal adsorption model. While adsorption exchange process for vanadium was in accordance with secondary adsorption exchange model kinetic equation. The reaction order was secondary-order. Adsorption rate increased with temperature, which belonged to particles diffusion process. Reaction activation energy was 14.165kJ·moL^-1.The proper condition of precipitation vanadium process was pH=8.0, the modulus K=2, temperature 50℃, the concentration of vanadium 30 g/L, the precipitation rate of vanadium more than 99%. The precipitation vanadium process was deduced by differential method. The reaction order was 2 and kinetic constant was 0.6×10^-3(mol·dm^-3)^-1·min^-1. Ammonium meta-vanadate preparation was secondary reaction, and the rate equation was r=0.6×10^-3（a-x）（b-x）. The infrared spectra of the precipitation products corresponded with standard atlas of ammonium meta-vanadate. Products was displayed by XRD, result showed that ammonium meta-vanadate with single structure and high purity. A qualified product V2O5 was obtained by calcining ammonium metavanadate, every technical indices met GB3283-87. The research results can provide reference for industrialization of stone coal roasting with sodium.更多还原