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通过计算反应Gibbs自由能对钒铬渣物相组成的氧化钠化过程进行理论分析,提出采用两步氧化钠化焙烧分离钒铬渣中的钒、铬。主要考察了焙烧温度、焙烧时间和苏打比对钒铬渣中钒、铬转浸率的影响。结果表明:钒铬渣氧化钠化焙烧提钒的最佳条件为焙烧温度830℃、焙烧时间2.5h和苏打比1.3,钒、铬的转浸率分别为88.6%和1.28%;提钒残渣氧化钠化焙烧提铬的最佳工艺条件为焙烧温度1100℃、焙烧时间2.5h和苏打比2.4,铬的转浸率大于80%。通过对渣相进行X射线衍射(XRD)和背散射电子(BSE)分析,钒铬渣焙烧熟料的主要物相为Fe_2O_3,FeTiO_3,Na_2Si_2O_5,NaVO_3和Cr_3O_8;进一步分析提钒残渣氧化钠化提铬机制,确定生成Na_2CrO_4的主要反应为CrO_3与Na_2Si_2O_5和NaFeO_2等中间产物发生的置换反应。
Through the calculation of reaction Gibbs free energy of the vanadium-chromium slag phase composition of the sodium oxide process, the proposed two-step sodium oxide roasting separation of vanadium and chromium slag vanadium, chromium. The effects of calcination temperature, calcination time and soda ratio on the vanadium and chromium transfer rates in vanadium-chromium slag were investigated. The results showed that the optimum conditions of vanadium and chromium slag roasting and vanadium extraction were as follows: the roasting temperature was 830 ℃, the roasting time was 2.5h and the soda ratio was 1.3, the vanadium and chromium conversion rates were 88.6% and 1.28% respectively; The optimal conditions for sodium extraction calcination were calcination temperature of 1100 ℃, calcination time of 2.5h and soda ratio of 2.4, chromium transfer rate of more than 80%. The main phases of roasted clinker vanadium slag were Fe 2 O 3, FeTiO 3, Na 2 Si 2 O 5, NaVO 3 and Cr 3 O 8 by X-ray diffraction (XRD) and backscattered electron (BSE) analysis of the slag phase. Chromium mechanism to determine the formation of Na_2CrO_4 the main reaction for CrO_3 and Na_2Si_2O_5 and NaFeO_2 and other intermediates occurred replacement reaction.