Accelerated leaching of heavy metals from Landfilled municipal solid waste incineration bottom ash

研究了垃圾焚烧底灰中重金属的辅助浸出机理。柠檬酸与尿素共存对重金属的络合作用影响最大，并促进了某些元素的浸出，特别是铬、铜、铁和磷。垃圾填埋场生成的黄腐酸虽然与铜离子具有很强的络合能力，但比天然黄腐酸的络合能力小两个数量级。结合ph依赖性浸出试验和顺序浸出试验，发现地球化学模拟结果与浸出试验结果存在较大差异。这表明浸出机制不受某些优势矿物的控制。此外，还得出了底灰中重金属的浸出是一个非常复杂的机制，包括溶解、沉淀和浸出过程中重金属向其他地球化学形式的转化。

Assisted leaching mechanisms of heavy metals from landfilled municipal solid waste incineration bottom ash was investigated. Citric acid co-existed with urea had the largest effect on the complexation with heavy metals and promoted the leaching of some elements, in particular chromium, copper, iron, and phosphorus. Although fulvic acid generated in landfill site had great complexation capacity with copper cation, it was two orders of magnitude smaller than that of natural fulvic acid. The combination of pH-dependent leaching tests and sequential extraction tests indicated great difference between geochemical simulation results and leaching test results. This suggested that leaching mechanisms were not controlled by some dominant minerals. In addition, it is also concluded that leaching of heavy metals from bottom ash are very complex mechanisms, which consisted of dissolution, precipitation, and conversions of heavy metals to other geochemical forms during leaching.