Chemical and Mineralogical Stabilization of Municipal Solid Waste Incinerator Bottom Ash for Recycled Material

在本研究中，实验在两种条件下进行。第一个试验是为了检验干湿过程对风化的影响（试验1）。将焚烧渣加入纯水调至30%含水量，分别在17℃、60℃、120℃的烘箱中烘干。完全干燥后，加入蒸馏水再次湿润至含水量30%。这样的过程不断重复以加速风化。风化后，根据日本浸出试验No. 46（JLT46；日本官方方法）和pH依赖性试验对样品进行重金属浓度分析，考察其洗脱特性。x射线衍射也被用于鉴定样品上存在的作为风化函数的结晶相。主要实验结果如下：(1)通过重复干湿过程，铅的浓度从19.0mg/l降至0.01mg/l。在110℃干燥的样品中，铅的固定化比低温下进展更快，说明高温对铅的固定化效果更好。(2)通过x射线衍射对铅化合物进行鉴定，证实风化前铅主要以Pb、PbS和PbSO_4形式存在。试验2风化后，PbSO_4在PbCO_3中发生了变化。认为铅的固定化是由碳酸化引起的。

In this study, experiments were carried out under two conditions. The first one was carried out in order to examine the effect of wetting and drying processes on weathering(Test 1). The incineration residue, adjusted to 30% water content by adding pure water, was dried by oven set at 17,60 and 120℃, respectively. After completely drying, they were wetted again to 30% water content by adding distilled water. Such a process was repeated to accelerate weathering. After weathering, samples were analyzed for concentrations of heavy metals based on Japan leaching test No. 46(JLT46;Japanese official method), and pH dependency test in order to examine their elution characteristics. The X-ray diffraction was also carried out to identify the crystalline phases existing on the samples as a function of weathering.The main experimental results are as follows :(1)By repeating the wetting and drying process, the concentration of the lead decreased from 19.0mg/l to 0.01mg/l. The lead immobilization of the sample dried at 110℃ progressed more in comparison with the lower temperatures, which suggests that high temperature is more effective on immobilization of lead.(2)As a result of identifying lead compounds by X-ray diffraction, it was confirmed that the lead before weathering existed mainly in the form of Pb,PbS and PbSO_4 forms. After the weathering in Test 2,PbSO_4 has changed in PbCO_3. It is considered that the immobilization of lead is caused by carbonation.