Ettler Vojtech, Sebek Ondrej, Grygar Tomás, Klementová Mariana, Bezdicka Petr, Slavíková Halka
Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic.
Environ Sci Technol. 2008 Nov 1;42(21):7878-84. doi: 10.1021/es801246c.
Air-pollution-control (APC) residues are among the most toxic waste materials from secondary Pb metallurgy. Two distinct APC residues collected from bag-type filters of one Czech secondary Pb smelter were subjected to leaching experiments to determine the mineralogical and geochemical controls on leaching of metallic contaminants (Cd, Cu, Pb, Zn). A kinetic 720-h leaching test in deionized water at a liquid-to-solid (L/S) ratio of 10 L kg(-1) and a 48-h leaching test at various L/S ratios (0.5, 1, 5, 10, 50, 100, 500, and 1000 L kg(-1)) were performed and coupled with the mineralogical investigation of solid residues (TEM/EDS, XRD) and PHREEQC-2 speciation-solubility modeling. The rapid release of contaminants into the solution at all the L/S ratios showed the rapid dissolution of primary phases. The leaching at high L/S ratios, representing long-term predictions of leaching behavior, showed that primary alkaline sulfates and chlorides (Na3Pb2(S04)3Cl and KCl.2PbCl2) were dissolved and anglesite (PbSO4) was formed as their final and stable alteration product. Primary amorphous PbSO3 partly crystallized during leaching and oxidized to anglesite. These results are consistent with the mineralogical investigation of soils exposed for decades to Pb smelter emissions, where only anglesite was detected. The leaching experiments showed thatwashing residues at L/S >50 accompanied by spontaneous anglesite precipitation can be an alternative for improved technological treatment of these residues. Although this process would require further treatment of contaminated effluent, the newly precipitated anglesite is more favorable than the primary APC residue phases for an efficient metallurgical recovery of Pb.
空气污染控制（APC）残渣是二次铅冶金中毒性最强的废料之一。从捷克一家二次铅冶炼厂的袋式过滤器收集的两种不同的APC残渣进行了浸出实验，以确定金属污染物（镉、铜、铅、锌）浸出的矿物学和地球化学控制因素。在去离子水中进行了720小时的动力学浸出试验，液固比为10 L kg⁻¹，以及在不同液固比（0.5、1、5、10、50、100、500和1000 L kg⁻¹）下进行了48小时的浸出试验，并与固体残渣的矿物学研究（透射电子显微镜/能谱仪、X射线衍射）和PHREEQC - 2形态 - 溶解度建模相结合。在所有液固比下，污染物迅速释放到溶液中，表明原生相迅速溶解。高液固比下的浸出代表了浸出行为的长期预测，结果表明原生碱性硫酸盐和氯化物（Na₃Pb₂(SO₄)₃Cl和KCl·2PbCl₂）溶解，最终形成稳定的次生产物白铅矿（PbSO₄）。原生无定形的PbSO₃在浸出过程中部分结晶并氧化成白铅矿。这些结果与暴露于铅冶炼厂排放物数十年的土壤的矿物学研究结果一致，在这些土壤中仅检测到白铅矿。浸出实验表明，在液固比>50的情况下洗涤残渣并伴随白铅矿自发沉淀，可能是改善这些残渣工艺处理的一种替代方法。尽管这个过程需要对受污染的废水进行进一步处理，但新沉淀的白铅矿比原生APC残渣相更有利于铅的有效冶金回收。
