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Development of Advanced Cleaning Technology for Hazardous Heavy Metals in Coal

煤中有害重金属先进净化技术开发

基本信息

批准号：
11218209
负责人：
OHKI Akira
金额：
$ 19.14万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

项目摘要

About the hazardous heavy metals in coal and coal ash, the development of measurement methods and the studies on the removal and leaching behaviors were carried out. The results obtained in this study are as follows.1. For the various elements in coal and coal fly ash, the measurement methods were established. The optimum conditions for the acid-decomposition by use of microwave processor were assessed. For volatile elements, such as Hg and F, the oxygen flask combustion method was also successful. The decomposition solutions obtained were analyzed, and the cold vapor AAS for Hg, hydride generation AAS for As and Se, ion-selective electrode for F, and ICP-AES for other elements were applied.2. The leaching behavior of various elements from coal to diluted acid solutions and chelating agent solutions was examined. Among heavy metals, Mn was easy to leach, while Cu, Pb, and Zn were also considerably leached. The leaching amount of element was almost proportional to its content in coal. The tendency of element leaching into diluted acid solutions was similar to that into chelating agent solutions.3. For the effective removal of Hg from coal, the heating of coal under nitrogen flow at 300-400℃ (mild pyrolysis) was proposed. Some coals showed high Hg removals of over 80%, whereas the Hg removal of some coals was very low. The difference in the Hg removal efficiency among coals was ascribed to that in the mode of occurrence of Hg in coal.4. It was proved that some hazardous elements, such as As, B, and Se, were easy to leach out from coal fly ash. When fly ash was subjected to a hydrothermal treatment, As was effectively removed from the ash. The wastewater obtained by the process was treated with an adsorbent, Al-loaded Shirasu zeolite, which had been newly prepared, resulting in the efficient removal of As from the wastewater.

针对煤和粉煤灰中的有害重金属，开展了测定方法的开发以及去除和淋滤行为的研究。本研究得到的结果如下： 1．建立了煤和粉煤灰中各种元素的测定方法。评估了微波处理酸分解的最佳条件。对于挥发性元素，如Hg和F，氧气瓶燃烧法也取得了成功。对分解液进行分析，对Hg采用冷蒸气原子吸收光谱法，对As、Se采用氢化物原子吸收光谱法，对F采用离子选择性电极分析，对其他元素采用ICP-AES分析。 2．研究了煤中各种元素在稀酸溶液和螯合剂溶液中的浸出行为。重金属中，Mn较容易浸出，而Cu、Pb、Zn也浸出较多。元素的浸出量与其在煤中的含量几乎成正比。元素在稀酸溶液中的浸出趋势与在螯合剂溶液中的浸出趋势相似。 3．为了有效去除煤中的汞，提出了在氮气流下将煤加热到300-400℃（轻度热解）。一些煤的汞去除率高达 80% 以上，而一些煤的汞去除率非常低。煤中Hg脱除效率的差异主要归因于煤中Hg的赋存方式不同。4．实践证明，粉煤灰中As、B、Se等有害元素很容易浸出。当飞灰经过水热处理时，As 被有效地从灰中去除。采用新制备的载铝Shirasu沸石吸附剂处理该工艺获得的废水，可有效去除废水中的砷。