低品位钒渣在碳酸钠存在下的氧化过程

利用XRD,SEM/EDS和TG-DSC等手段对低品位钒渣在Na2CO3存在条件下的氧化过程进行检测。结果表明：钒渣的氧化温度范围为273至700°C,橄榄石相与尖晶石相彻底分解的温度分别是500和600°C,大部分水溶性的钒酸盐在500与600°C之间形成。当温度达到700°C以上时,钒酸盐富集相明显可见,但焙烧温度在800°C以上时,样品发生烧结,并且钒被形成的玻璃相包裹,导致其浸出率下降。同时,研究不同焙烧温度对钒浸出率的影响,并对浸出残渣进行分析。

Oxidation process of low-grade vanadium slag in presence of Na2CO3

The oxidation process of low-grade vanadium slag in the presence of Na₂CO₃ was investigated by XRD, SEM/EDS and TG-DSC techniques. The results show that the vanadium slag is oxidized in a temperature range from 273 to 700 °C. Olivine phases and spinel phases are completely decomposed at 500 and 600 °C, respectively. Most of water-soluble sodium vanadates are formed between 500 and 600 °C. When roasting temperature reaches above 700 °C, the vanadium-rich phases of sodium vanadates can be obviously observed. However, at temperature above 800 °C, the samples are sintered. Most of the vanadium is enwrapped by glassy phase compounds which lead to the decrease of the leaching rate of vanadium. At the same time, the effect of roasting temperature on extraction of vanadium and characterization of leach residues were discussed.