湿法冶金

针对高钠碱性反萃富钒液在传统沉钒过程中易出现局部过饱和度过高，进而引发爆发式成核、杂质机械夹带严重等问题，研究采用恒定pH双流体控制结晶工艺制备偏钒酸铵(AMV)前驱体，再经煅烧获得高纯V_2O₅。采用沉钒缓冲液缓慢流加与恒定pH控制相结合的方式，系统考察了加铵系数、反应时间和温度对沉钒率和产物纯度的影响，并借助XRD、SEM及ICP-OES对产物的物相组成、微观形貌和杂质分布进行分析。结果表明：在加铵系数为1.5、反应时间120min、温度85℃条件下，沉钒率可达98.5%；控制结晶所得前驱体呈现短柱状和厚板状的有序堆积结构，明显改善了传统快速沉淀中常见的无序絮凝和母液包裹现象；前驱体经500℃煅烧脱水脱氨后发生形貌重构，尽管存在热力学杂质浓缩效应，最终所得V_2O₅纯度仍高达99.89%。该工艺能够从源头上有效抑制高钠体系中的杂质夹带，为高纯V_2O₅的绿色制备提供了一种可行途径，具有一定应用前景。

Aiming at the problems of excessive local supersaturation in the traditional vanadium precipitation process of high sodium alkaline stripping vanadium-rich solution,which leads to explosive nucleation and serious mechanical entrainment of impurities,the preparation of ammonium metavanadate(AMV)precursor by constant pH two-fluid controlled crystallization process was studied,and then high purity V_2O₅ was obtained by calcination.The effects of ammonium addition coefficient,reaction time and temperature on the vanadium precipitation rate and product purity were systematically investigated by combining the slow flow of vanadium precipitation buffer and constant pH control.The phase composition,microstructure and impurity distribution of the product were analyzed by XRD,SEM and ICP-OES.The results show that the precipitation rate of vanadium can reach 98.5% under the conditions of ammonium addition coefficient of 1.5,reaction time of 120 min and temperature of 85 ℃.The precursor obtained by controlled crystallization exhibits an ordered stacking structure of short column and thick plate,which significantly improves the common disorderly flocculation and mother liquor encapsulation in traditional rapid precipitation.After calcination at 500℃ for dehydration and deamination,the morphology of the precursor is reconstructed.Despite the thermodynamic impurity concentration effect,the purity of the final V_2O₅ is still as high as 99.89%.This process can effectively inhibit impurity entrainment in high-sodium systems at the source,providing a feasible pathway for the green preparation of high-purity V_2O₅ and demonstrating certain application prospects.