A novel resource utilization of the calcium-based semi-dry flue gas desulfurization ash is investigated. In the present study, the semi-dry desulfurization ash is used as a reductant for chromium and vanadium removal by chemical reduction precipitation, the byproduct gypsum and chromium-contained sludge are obtained. Besides, the effects of main operational parameters (reaction pH, desulfurization ash dosage and reaction time) on the heavy metal removal are investigated, and the main reaction mechanism for this treatment technology is also proposed. Under the optimal conditions, the residual concentrations of Cr(VI), total Cr and V are 0.163 mg/L, 0.395 mg/L and 0.155 mg/L, respectively. Additionally, byproduct gypsum and chromium-contained sludge are characterized using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), scanning electron microscope-energy dispersive spectrometer (SEM-EDS) and thermogravimetry differential scanning calorimetry (TG-DSC), respectively. Finally, the resource utilization methods of the byproduct gypsum and chromium-contained sludge from this technology are also submitted. The byproduct gypsum can be utilized to produce hemihydrate calcium sulfate whisker, and the roasted heavy metal precipitation can be used as a primary chromium raw material (Cr₂O₃ content is about 83%).

中文翻译：

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钙基半干烟气脱硫灰的新型资源利用：作为还原剂从钒工业废水中去除铬和钒

研究了钙基半干法烟气脱硫灰的一种新型资源利用方法。在本研究中，将半干式脱硫灰用作通过化学还原沉淀去除铬和钒的还原剂，获得了副产物石膏和含铬污泥。此外，研究了主要操作参数（反应pH，脱硫灰剂量和反应时间）对重金属去除的影响，并提出了该处理技术的主要反应机理。在最佳条件下，Cr（VI），总Cr和V的残留浓度分别为0.163 mg / L，0.395 mg / L和0.155 mg / L。此外，还使用X射线衍射（XRD），傅立叶变换红外光谱（FT-IR）对副产物石膏和含铬污泥进行了表征，扫描电子显微镜-能量分散光谱仪（SEM-EDS）和热重分析差示扫描量热法（TG-DSC）。最后，还提出了该技术对副产物石膏和含铬污泥的资源利用方法。副产品石膏可用于生产半水合硫酸钙晶须，并且焙烧的重金属沉淀物可用作主要的铬原料（铬₂ O ₃含量约为83％。