School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST) , Wuhan, Hubei 430074, China.
State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology (HUST) , 1037 Luoyu Road, Wuhan, Hubei 430074, China.
Environ Sci Technol. 2018 Feb 20;52(4):2235-2241. doi: 10.1021/acs.est.7b05283. Epub 2018 Jan 30.
Spent lead-acid battery recycling by using conventional technologies is usually accompanied by releases of lead-containing wastewater as well as emissions of sulfur oxides and lead particulates that may potentially cause secondary pollution. This study developed a vacuum chlorinating process for simultaneous sulfur fixation and high-purity lead chloride (PbCl) recovery from spent lead paste by using calcium chloride (CaCl) and silicon dioxide (SiO) as reagents. The process train includes pretreatment, simultaneous PbCl production and sulfur fixation, and PbCl volatilization. The pretreatment eliminated chlorine emission from direct chlorinating reaction of PbO in the initial S-paste (PbSO/PbO/PbO/Pb). During the subsequent PbCl production and sulfur fixation step, lead compounds in the P-paste (PbSO/PbO) was converted to volatile PbCl, and sulfur was simultaneously fixed to the solid residues in the form of CaSO to eliminate the emission of sulfur oxides. The final step, PbCl volatilization under vacuum, is a physical phase-transformation process of ionic crystals, following a zeroth-order kinetic model. A cost estimate indicates a profit of USD $ 8.50/kg PbCl. This process offers a novel green lead recovery alternative for spent lead-acid batteries with environmental and economic benefits.
采用传统技术回收废铅酸电池通常伴随着含铅废水的排放以及二氧化硫和铅颗粒的排放，这些可能会造成二次污染。本研究采用氯化钙（CaCl）和二氧化硅（SiO）作为试剂，开发了一种真空氯化工艺，从废铅膏中同时固定硫并回收高纯度氯化铅（PbCl）。该工艺路线包括预处理、同时生产 PbCl 和固定硫以及 PbCl 挥发三个步骤。预处理消除了初始 S 膏（PbSO/PbO/PbO/Pb）中 PbO 直接氯化反应产生的氯气排放。在随后的 PbCl 生产和固定硫步骤中，P 膏（PbSO/PbO）中的铅化合物被转化为挥发性 PbCl，同时硫以 CaSO 的形式固定在固体残渣中，从而消除了二氧化硫的排放。最后一步是在真空中挥发 PbCl，这是离子晶体的零级动力学模型的物理相转变过程。成本估算表明，每公斤 PbCl 的利润为 8.50 美元。该工艺为废铅酸电池的铅回收提供了一种新颖的绿色替代方案，具有环境和经济效益。
