钙化提钒过程中元素迁移转化行为的研究

Study on migration and transformation behavior of elements during vanadium extraction by calcification

试验结合XRD、XPS、SEM-EDS和ICP-OES等分析手段,研究了不同pH值条件下酸性铵盐沉钒产物的物相组成及形貌,并分析了沉钒pH值等于2.20时V、Fe和Mn三种元素的迁移转化行为。结果表明,沉钒pH值显著影响产物的组成和形貌,较低pH值沉钒滤饼为无定形结构,随着pH值的升高,晶型逐渐确定。V在提钒尾渣中以CaV2O6形式存在,在滤饼中以多聚钒酸根形式存在,终产品中则以V2O5的形式存在;Fe在尾渣中的主要存在形式为Fe2O3和Fe2TiO5,在沉钒滤饼和终产品中含量较少;Mn在尾渣中以MnSO4形式存在,沉钒过程中主要进入到上清液中,滤饼中则以MnV2O6·4H2O形式存在,终产品中有0.210%。

Combined with XRD,XPS,SEM-EDS and ICP-OES characterizations,the phase composition and morphology of acid ammonium salt precipitation vanadium products under different pH values were studied;also the migration and transformation behavior of V,Fe and Mn were analyzed when the pH value of vanadium precipitation was 2.20.The results show that the pH value of vanadium precipitation significantly affects the composition and morphology of the product.The filter cake of vanadium precipitation is amorphous at low pH value,and the crystal form is gradually determined with the increase of pH value.V exists in the form of CaV2O6 in vanadium extraction tailings,polyvanadate in filter cake,and V2O5 in the final product.The main forms of Fe in tailings are Fe2O3 and Fe2TiO5,which are less abundant in vanadium filter cake and final product.Mn exists in the form of MnSO4 in the tailings,and mainly enters the supernatant during vanadium precipitation,while MnV2O6·4H2O exists in the filter cake and with 0.210%in the final product.