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熔融钒渣直接氧化提钒中碱性添加剂的主要作用是与氧化钒结合生成可溶性钒酸盐,以便后续湿法浸出。以Na2CO3和CaO为例,通过理论分析和实验室实验着重研究了碱性添加剂对转炉熔融钒渣吹氧氧化行为的影响。结合后续的湿法浸出实验研究熟料中钒的氧化状态以及其与钒浸出的关系,利用X射线光电子能谱仪(XPS)对钒渣熟料中钒的价态含量进行分析。理论分析表明熔融钒渣中的钒氧化成高价在热力学和动力学上均存在一定限制,强制供纯氧和添加碱性添加剂有利于促进钒的氧化。实验结果发现,无添加剂条件下,熔渣中钒的氧化率极限约在80%,Na2CO3和CaO的存在有助于促进熔渣中钒的氧化。随着Na2CO3和CaO含量的增加,钒的氧化率与酸浸出率有增加的趋势,区别为钠法中钒的氧化率与水浸率协同增加,而钙法中,当钒氧化率为65%时酸浸率的峰值出现,钙化熟料中CaV2O5比Ca2V2O7更容易用酸浸出。
The main role of vanadium slag direct oxidation of alkaline additives in vanadium is to combine with vanadium oxide to form soluble vanadate for subsequent wet leaching. Taking Na2CO3 and CaO as examples, the effects of basic additives on the oxygen blowing behavior of vanadium slag by converter were studied emphatically through theoretical analysis and laboratory experiments. The oxidation state of vanadium in clinker and its relationship with vanadium leaching were studied by the subsequent wet leaching experiments. The vanadium valence content in vanadium slag clinker was analyzed by X-ray photoelectron spectroscopy (XPS). Theoretical analysis shows that vanadium oxide in molten vanadium slag has high thermodynamics and kinetics. There are some limitations in the thermodynamics and kinetics. Supplying pure oxygen and adding alkaline additives are helpful to promote the oxidation of vanadium. The experimental results show that without additives, vanadium oxidation rate in slag is about 80%, and the presence of Na2CO3 and CaO help to promote vanadium oxidation in slag. With the increase of Na2CO3 and CaO content, the oxidation rate and the acid leaching rate of vanadium tend to increase. The difference is that the oxidation rate of vanadium increases synergistically with the water leaching rate in the sodium process. However, when the vanadium oxidation rate is 65% At the peak of acid leaching rate, CaV2O5 in calcified clinker leaches more easily than Ca2V2O7.