粉煤灰及其硬化体中六价铬离子的溶出现象

粉煤灰中含有一定数量的六价铬离子，鉴于粉煤灰使用的广泛性和六价铬离子对人体与生态的危害性，必须就粉煤灰中六价铬离子的溶出性能和溶出抑制方法进行研究，并制定相应的对策与措施以指导粉煤灰的合理与安全使用。探讨了粉煤灰和粉煤灰硬化体中六价铬离子的溶出性能。研究结果表明，无论是粉煤灰本身还是自干硬击实粉煤灰硬化体或粉煤灰泥浆硬化体，都有一定数量的六价铬离子溶出，其溶出量与粉煤灰的铬含量、比表面积及粒径、火山灰活性和试体成型方法等有关。一般来说，干硬击实粉煤灰硬化体中六价铬离子的溶出量较泥浆硬化体的高。

Leaching Behavior of Cr (Ⅵ) from Fly Ash and Hardened Fly Ash

Fly ash contains a certain amount of hexavalent chromium ions, which is mainly dependent on the source and combustion condition of coal, ash kind, and ash collection methods. As fly ash is a widely used material and hexavalent chromium is harmful to human health and environment, attention to the leaching of hexavalent chromium is needed. The leaching behavior of hexavalent chromium in hardened fly ashes has been investigated. The results show that hexavalent chromium leaches both from fly ashes and hardened fly ashes and the amount of chromium leached is related to chromium content of fly ash, specific surface area, particle size, pozzolanic activity of fly ash and the making method of specimens as well. In general, hardened fly ashes compacted at the optimum moisture content are with higher hexavalent chromium leachability than hardened fly ash slurry.