In this study, it was aimed to extract vanadium (V) and nickel (Ni) from a petroleum coke ash (PCA) using a roasting process without additives, followed by leaching with sulfuric acid (H₂SO₄). The experiments were designed based on the Taguchi approach, taking into account the parameters of temperature, acid concentration, time, and solid ratio. Additional leaching tests were conducted on the non-roasted PCA for comparison, to assess the effect of roasting on the extractions of V and Ni. The results showed that no extra reducing agent was needed as the PCA contained high levels of CaCO₃, which could be used as a reducing agent during roasting. It was found that roasting was essential for high Ni extractions, but had no strong effects on V extractions. The Ni extraction was found to be between 13.3 and 80.8% for the non-roasted PCA and between 43.6 and 99.3% for the roasted PCA. The V extraction was between 36 and 97.9% for the non-roasted PCA and between 45.4 and 99.9% for the roasted PCA. The optimal leaching conditions were determined to be a sulfuric acid of 4.5 M, a solid ratio of 10%, a temperature of 75 °C, and a time of 75 min. In addition, it was determined that the leaching conditions had a great effect on the oxidation state of vanadium ions, and an increase in the acid concentration led to the formation of V³⁺ ions (green color) instead of VO²⁺ ions (blue color) in the pregnant leach solution. The final pregnant leach solution containing 1056.50 mg/L V, and 251.85 mg/L Ni was achieved with an extraction yields of > 98%. The experimental results were greatly fitted by the shrinking core model and the activation energy (E_a) for V and Ni was calculated as 3.60 and 4.01 kJ/mol, indicating that the leaching mechanism can be explained by the diffusion control model.

Graphical Abstract

中文翻译：

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焙烧酸浸从高碳酸钙石油焦灰中回收钒和镍

在本研究中，目的是使用无添加剂的焙烧工艺从石油焦灰（PCA）中提取钒（V）和镍（Ni），然后用硫酸（H 2 SO ₄）_浸出。实验是基于田口方法设计的，考虑了温度、酸浓度、时间和固体比等参数。对未烘烤的 PCA 进行了额外的浸出测试以进行比较，以评估烘烤对 V 和 Ni 提取的影响。结果表明，不需要额外的还原剂，因为PCA含有高含量的CaCO ₃，可以在烘焙过程中用作还原剂。研究发现，焙烧对于高镍提取率至关重要，但对 V 提取率影响不大。未烘烤的 PCA 的 Ni 提取率为 13.3% 至 80.8%，烘烤的 PCA 的 Ni 提取率为 43.6% 至 99.3%。未烘烤的 PCA 的 V 提取率为 36% 至 97.9%，烘烤的 PCA 的 V 提取率为 45.4% 至 99.9%。确定最佳浸出条件为硫酸浓度4.5 M、固形比10%、温度75 ℃、时间75 min。此外，还确定浸出条件对钒离子的氧化态有很大影响，酸浓度的增加导致形成V 3+ 离子^（绿色）而不是VO ²⁺离子（蓝色）。颜色）在浸出液中。最终的富浸液含有 1056.50 mg/LV 和 251.85 mg/L Ni，提取率 > 98%。实验结果与缩核模型非常吻合，计算得出V和Ni的活化能(E _{a )分别为3.60和4.01 kJ/mol，表明浸出机理可以用扩散控制模型来解释。}

图形概要