Abstract:

The waste acid fluidized bed regeneration technology can efficiently recover acid and metal ions, and has a broad application prospect. The effect of temperature in the dense phase zone and initial bed size on the regeneration and recovery characteristics of acid and metal ions in waste mixed acid (HNO₃+HF) was investigated by using a self-built fluidized bed thermal state experimental setup and combining SEM, ion chromatography and XPS characterization methods. The results show that the fluidized bed method can effectively achieve the regenerative recovery of acid and metal elements in waste mixed acid, and the amount of metal oxide adhered to the surface of the bed material increases with the increase in temperature of the fluidized bed dense phase zone, reaching a peak at 850℃. The amount of adherence decreases slightly as the temperature continues to rise. By increasing the initial particle size of the bed material, the amount of metal oxide adhered to the surface of the bed material will be significantly increased. The amount of NO _x and HF generation increases with the increase of temperature in the dense phase zone of the fluidized bed, reaching a peak at 750℃, and then decreases significantly after continuing to increase the temperature, while the amount of NO _x generation will decrease slightly as the initial particle size of the bed material increases, and the temperature in the dense phase zone corresponding to the peak of HF generation is delayed to 800℃.

Key words: waste mixed acid, regeneration, fluidized bed, roasting, stainless steel pickling

摘要：

废酸流化床法再生技术可高效回收酸和金属离子，具有广阔的应用前景。利用自行搭建的流化床热态实验装置，并结合SEM、离子色谱和XPS等表征手段研究了密相区温度、初始床料粒径对废混酸（HNO₃+HF）中酸与金属离子再生回收特性的影响规律。结果表明：流化床法可有效实现废混酸中酸和金属元素再生回收，金属氧化物在床料表面附着量随流化床密相区温度的升高而增加，850℃时达到峰值，继续升温后附着量小幅降低，同时增大床料初始粒径，金属氧化物在床料表面附着量将大幅提高；NO _x 、HF生成量随流化床密相区温度的升高而增加，750℃时达到峰值，继续升温后大幅回落，同时随着床料初始粒径增大，NO _x 生成量将小幅降低，而HF生成量峰值对应的密相区温度变化到800℃。

关键词: 废混酸, 再生, 流化床, 焙烧, 不锈钢酸洗