碱性系统中fe对cr的还原和沉淀作用及其对飞灰中cr溶出控制的影响

碱性系统中 Fe 对 Cr 的还原和沉淀作用及其对飞灰中 Cr 溶出控制的影响*摘要：本文讨论了碱性系统中亚铁对 Cr 的还原反应热力学，并检验了二价铁(亚铁)以 FeSO4的形式加入飞灰水系统中和飞灰溶液中两种情况下对六价铬()的还原效果，实验了被亚铁所还原的铬的稳定性。实际过程中，Cr 自飞灰等废渣中的溶出还受吸附/沉淀等作用的影响，在本文中也利用 Fe 的氧化物/氢氧化物对进行了吸附沉淀检验。讨论结果表明不仅亚铁在碱性环境中仍能还原，而且 Fe 的氧化物/氢氧化物对也具有一定的吸附和沉淀效果。本讨论对飞灰等残渣中Cr 的浸出控制有重要的指导意义。关键词：铬，碱性，飞灰，亚铁，还原，吸附/沉淀Reduction and Precipitation Effect of Fe on Cr in Alkaline System and Its Application in Controlling Cr Release from Fly AshAbstract: Reduction properties of chromium (Cr) by ferrous iron in alkaline system were analysed from point view of thermodynamics and investigated in the laboratory with a purpose to control Cr release from incineration fly ash. In laboratory, fly ash solution was obtained by washing fly ash in water and then separating the two. Ferrous iron was added to fly ash-water mixture and to fly ash solution respectively to check its reactivity on reduction; and for two of the later reactors, the reduced products were collected and their stability were investigated by leaching in the water. Considering that in the fly ash – water system, release of Cr from fly ash to aqueous phase is also influenced by absorption/precipitation process, product from oxidised ferrous sulphate in alkaline solution and ferrite sulphate were used to check absorption / precipitation abilities of ferrite oxides/hydrate for . Laboratory experimental results showed that in alkaline solution even pH value is as high as 13, ferrous iron can reduce effectively. However, ferrous iron cannot effectively reduce in the fly ash ...