以流化床和炉排炉两种垃圾焚烧电厂产生的底灰为对象,研究了底灰中总铬及六价铬的分布特性及六价铬分布与Ca、Si、Al等矿物元素之间的关系,并探索了六价铬的浸出特性。得到结论如下:随着底灰粒径的增大,底灰中总铬及六价铬含量降低;Si和Al的存在的情况下,CaO会与Si和Al发生反应,直接影响Cr(VI)的生成;采用炉排炉焚烧工艺得到的底灰比采用流化床工艺得到的底灰中六价铬浸出浓度高;底灰中存在的还原性物质,尤其是流化床底灰,促使浸出过程中六价铬的还原,降低浸出溶液中六价铬的含量。
In this paper, the distribution character of total chromium and Cr(VI) in the bottom ashes from both fluid-bed and grate furnace types municipal solid waste incineration plants were investigated. The Leaching behavior of Cr(VI) and the relationship between the Cr(VI) distribution and contents of Ca, Si, Al in the bottom ashes were also studied. The main conclusions can be drawn as follows: the contents of total chromium and Cr(VI) decrease with the increase of particle sizes of bottom ashes; when Si and Al exist, CaO would react with them, this would affect Cr(VI) generation directly; the leaching concentration of Cr(VI) is higher in the grate furnace bottom ash than in the fluid-bed bottom ash; the reducing materials in the bottom ash cause Cr(VI) be reduced, and then affect the leaching behavior of Cr(VI), especially for fluid-bed bottom ash.