二次铝灰酸浸制备聚合氯化铝的研究

二次铝灰中仍含大量铝，对其进行回收具有重要意义。文中以二次铝灰为原料，通过盐酸浸出处理后再添加铝酸钙制备聚合氯化铝（PAC），研究了HCl浓度、浸出温度、时间、液固比，铝酸钙添加量等因素的影响。综合考虑，适合二次铝灰酸浸制备聚合氯化铝的较优条件为:水洗后的二次铝灰在HCl浓度为6 mol/L，液固比为4∶1 mL/g，温度为85 ℃条件下酸浸2 h，此时的酸浸液中加入12 g/80 mL的铝酸钙，温度为85 ℃条件下反应1.5 h。该条件下酸浸过程中铝的浸出率为48.67%，且制得的液体PAC完全符合国家标准。 

Study on the preparation of polyaluminum chloride by acid leaching of secondary aluminum dross

The secondary aluminum dross still contains a large amount of metallic aluminum, and its recycling is of great significance. In this paper, secondary aluminum ash was used as the raw material. After treating it by hydrochloric acid leaching, calcium aluminate was then added to prepare polyaluminum chloride (PAC). The influencing factors such as the concentration of HCl, leaching temperature, time, liquid-solid ratio, and calcium aluminate addition amount were mainly investigated. The best conditions for preparing polyaluminum chloride by acid leaching of secondary aluminum dross were as follows: the secondary aluminum dross after washing was leached at the HCl concentration of 6 mol/L, the liquid-solid ratio of 4∶1 mL/g, at 85 ℃ for 2 h, and then added calcium aluminate 12 g/80 mL to the acid leaching solution and reacted at 85 ℃ for 1.5 h. Under these conditions, the leaching rate of aluminum during the acid leaching process was 48.67%, and the liquid PAC prepared was fully compliance with the national standard.