School of Resources & Environmental Engineering, Wuhan University of Technology, 430070 Wuhan, China.
School of Resources & Environmental Engineering, Wuhan University of Technology, 430070 Wuhan, China.
Sci Total Environ. 2019 May 10;664:53-59. doi: 10.1016/j.scitotenv.2019.01.424. Epub 2019 Feb 2.
Calcium carbonate (CaCO) may be used for lead removal. However, due to compact structure and high crystallinity of CaCO, the utilization of CO is low and Pb removal only stays at the extent of physical adsorption and surface precipitation. In this research, a wet stirred ball milling process was introduced to induce nearly stoichiometric reactions between lead salts of nitrate, chloride or sulfate with CaCO by consequently updating fresh surfaces of CaCO. The CaCO could completely dissolve in the system for the removal of Pb on the same chemical molar equivalent. The removal rate reached simply over 99% with the aid of ball milling, based on the precipitations in the forms of lead carbonate (PbCO) from soluble nitrate and basic lead carbonate (Pb(CO)(OH)) from the hardly soluble sulfate occurring in a very wide concentration range. The process offered a new path for the treatment of abandoned lead paste based on the conversion of PbSO to PbCO or Pb(CO)(OH) as well as recycling of lead resources from multi-metal coexisting lead-containing waste solutions. These (basic) carbonates precipitates may be used as secondary resources, while achieving environmental purification.
碳酸钙（CaCO）可用于去除铅。然而，由于 CaCO 的结构紧凑和结晶度高，CO 的利用率较低，Pb 的去除仅停留在物理吸附和表面沉淀的程度。在这项研究中，引入了湿搅拌球磨工艺，通过不断更新 CaCO 的新鲜表面，在硝酸盐、氯化物或硫酸盐的铅盐与 CaCO 之间诱导近乎化学计量的反应。由于相同的化学摩尔当量，CaCO 可完全溶解在系统中以去除 Pb。在球磨的帮助下，去除率仅超过 99%，基于可溶性硝酸盐中形成的碳酸铅（PbCO）和难溶性硫酸盐中形成的碱式碳酸铅（Pb(CO)(OH)）的沉淀，在非常宽的浓度范围内发生。该工艺为处理基于将 PbSO 转化为 PbCO 或 Pb(CO)(OH)的废弃铅膏以及从共存多种金属的含铅废溶液中回收铅资源提供了一条新途径。这些（碱性）碳酸盐沉淀物可用作二次资源，同时实现环境净化。
