Ganne Patrick, Cappuyns Valérie, Vervoort André, Buvé Lucia, Swennen Rudy
Fysico-chemische Geologie, K.U.Leuven, Celestijnenlaan 200C, B-3001 Heverlee-Leuven, Belgium.
Sci Total Environ. 2006 Mar 1;356(1-3):69-85. doi: 10.1016/j.scitotenv.2005.03.022.
At Angleur (eastern Belgium), a 53,000 m3 dump site, related to former Zn extraction, contains high concentrations of heavy metals and arsenic associated with minerals such as arsenopyrite (FeAsS), franklinite (ZnFe2O4) and willemite (Zn2SiO4). Eight representative samples were investigated by means of a modified availability test, which pointed towards a considerable availability of Cd, Pb and Zn. In addition a detailed analysis of leaching behaviour as a function of pH was performed by means of a pH(stat) leaching test. The results of this test were supported by modelling predictions with MINTEQA2. pH(stat) titration results also allowed determination of the acid neutralising capacity, making it possible to predict heavy metal release upon acidification, assuming a worst-case scenario. On a short- to medium-long term (+/-100 years) a release of 900 mg/kg Zn has to be expected upon assumed natural acidification. However, a leaching test performed at the natural pH (i.e. pH 8 for the sample studied) indicates that heavy metal release is very limited and far below the European limit values for slag material on dumps category 1. Therefore, despite the elevated total heavy metal and As concentrations on the site, leaching is relatively low under present environmental conditions. Moreover, the slag material has a rather elevated pH (6.5-8) and no acid mine drainage is produced. Glass phases seem very important in controlling heavy metal mobility since potential reactive minerals that are locked up in a silicate matrix are protected against leaching.
在比利时东部的安勒尔，一个与以前的锌提取相关的53000立方米垃圾场含有高浓度的重金属和与毒砂（FeAsS）、锌铁尖晶石（ZnFe₂O₄）和硅锌矿（Zn₂SiO₄）等矿物相关的砷。通过改良的有效性测试对八个代表性样品进行了研究，结果表明镉、铅和锌具有相当高的有效性。此外，通过pH（stat）浸出试验对浸出行为随pH值的变化进行了详细分析。该试验结果得到了MINTEQA2模型预测的支持。pH（stat）滴定结果还可以确定酸中和能力，从而在假设最坏情况的前提下预测酸化时重金属的释放。在短期至中长时期（约100年）内，假设自然酸化的情况下预计锌的释放量为900毫克/千克。然而，在自然pH值（即所研究样品的pH值为8）下进行的浸出试验表明，重金属的释放非常有限，远低于欧洲第1类垃圾场炉渣材料的限值。因此，尽管该场地的总重金属和砷浓度较高，但在目前的环境条件下浸出率相对较低。此外，炉渣材料的pH值较高（6.5 - 8），且未产生酸性矿山排水。玻璃相在控制重金属迁移方面似乎非常重要，因为被锁定在硅酸盐基质中的潜在活性矿物受到保护而不被浸出。
