镁化焙烧钒渣中钒的酸浸动力学研究

Acidic leaching kinetics study on vanadium from magnesiation-roasted vanadium slag

为了促进钒渣镁化焙烧−酸浸提钒法的工业应用,研究钒渣镁化焙烧熟料中钒的酸浸出动力学。结合XRD、XPS和SEM,揭示在浸出初期的10 min内,MgSiO_(3)和大部分钒酸盐急剧地消耗酸,形成SiO2和V(V)的氧钒根离子。通过研究钒浸出效率随浸出时间的变化,建立钒浸出的动力学模型。结果表明,浸出过程分为两个不同的阶段,且两个阶段的动力学均遵循收缩核模型。0~10 min的浸出速率由固体产物层扩散和化学反应共同控制,而10~30 min的浸出速率仅由化学反应控制。因此,浸出初始10 min内加速传质很关键,而后续20 min内精确控温至关重要。

In order to promote the industrial application of the magnesiation roasting–acid leaching method,the acidic leaching kinetics of vanadium from magnesiation-roasted vanadium slag was investigated.By combination of XRD,XPS,and SEM,it was revealed that MgSiO_(3)and most vanadates consumed acid sharply to produce SiO2 and V(V)-containing vanadyl in the initial 10 min.The variation of vanadium extraction efficiency with leaching time was studied to establish the kinetic models for leaching.Results indicated two distinct stages in the leaching process and the kinetics of both stages followed the shrinking core model.The leaching rate in 0−10 min was controlled by both solid product layer diffusion and chemical reactions,while the leaching rate in 10−30 min was controlled only by chemical reactions.Therefore,it is essential to accelerate the mass transfer in initial 10 min and accurately control the temperature in the following 20 min during leaching.