【作者】 纪宪坤；

【导师】 钱觉时；

【作者基本信息】 重庆大学 ， 材料科学与工程， 2007， 硕士

【摘要】 流化床燃煤固硫技术是为了适应环境保护的要求而发展起来的先进煤燃烧技术,但由于目前对其副产物,即流化床燃煤固硫灰渣(以下简称固硫灰渣)的特性了解有限,在一定程度上影响了其资源化利用,甚至影响到了该技术的进一步推广。固硫灰渣的几种特性如吸水性能、水化膨胀性能等严重影响了其在水泥混凝土领域的应用,论文选择多种固硫灰渣,针对这些不利特性,研究了固硫灰渣的资源化利用方式,并探讨了抑制固硫灰渣膨胀的方法。固硫灰渣颗粒形貌极其不规则且疏松多孔,堆积密度较小;固硫灰的标准稠度需水量比粉煤灰高很多,固硫渣的吸水率也很高;固硫灰渣具有较强的水化自硬性。固硫灰渣稳定固化污泥可以充分利用这些特性,并且能够取得较理想的稳定固化效果。(1)固硫渣与污泥质量比为2:1,固硫灰与污泥质量比为1:1即可取得较好的固化效果。固化体系在前7d内pH值能够保持在11以上,这样的强碱性环境能够保证固化体系对污泥的杀菌效果;28d时固化体系pH值在9左右,为植被恢复提供了必要的条件。(2)固硫渣污泥固化体系28d强度能够达到2MPa左右,固硫灰污泥固化体系28d强度为1MPa左右。固硫灰渣污泥稳定固化体系重金属浸出毒性满足国家标准要求。(3)固硫灰渣污泥固化体系中加入固硫灰渣质量20%的石灰,能够提高固硫灰渣污泥固化体系的杀菌效果。固硫灰渣的火山灰活性较高,自身水化后会发生明显的体积膨胀,根据这些特性可以利用固硫灰渣配制建筑膨胀砂浆。(1)对于固硫渣而言,最佳配比如下:胶凝材料中固硫渣:水泥:粉煤灰=0.56:0.2:0.24,此时强度发展和膨胀率都较理想。(2)固硫灰建筑砂浆胶凝材料配比为固硫灰:水泥:粉煤灰=0.56:0.2:0.24或固硫灰:水泥=0.8:0.2,两组配比的强度发展和膨胀率都比较理想。(3)固硫灰渣配制所得建筑砂浆粘结强度、干密度、抗压强度、抗折强度满足《蒸压加气混凝土用砌筑砂浆与抹灰砂浆》(JC 890-2001)标准要求。固硫渣胶砂体系中加入固硫渣质量1%的CaCl2或Na2CO3都能够抑制固硫渣的膨胀,28d自由线性膨胀率能够减少19%左右,对胶砂强度影响较小,但这种抑制膨胀的方法效果并不明显。更多还原

【Abstract】 Fluidized bed combustion (FBC) technology is advanced because it can meet the demand of environment protection, but the byproducts, namely FBC ashes, are still something new to most people. As a result, the utilization of them and even the further promotion of the technology are seriously hampered. Some properties of FBC ashes such as water absorbing abilities and expansion have seriously affected their application in the cement concrete. Several kinds of FBC ashes are chosen in the paper. The recycle treatment of FBC ashes are mainly studied in the paper. Meanwhile, the ways to reduce the expansion ratio of FBC ashes are mentioned.The particles of FBC ashes are irregular and loose textured, so the water requirement of normal consistency of FBC fly ashes is much higher than that of PC fly ash, and the water absorption of FBC bottom ashes is very high. FBC ashes can be used for stabilization and solidification of sewage sludge. (1) For the bed ash, the appreciate mix proportion to sludge is 2:1.For the fly ash, the mix proportion is 1:1.The pH value of solidification admixture can keep above 11 at the first 7 days. The alkaline environment can guarantee the sterilization effect. At 28d, the pH value is about 9. This can offer the essential condition for the vegetation resumes. (2) At 28d, the strength of solidification admixtures of bed ash and sludge is about 2MPa and fly ash is about 1MPa. The heavy metal leaching properties of stabilized/solidified admixture of FBC ashes and sludge can meet Chinese standard.(3) The addition of twenty percent of lime in the stabilized/solidified admixture can improve the sterilization effect.The pozzolanic reactivity of FBC ash is high and great expansion takes place when it hydrates. Mortars can be produced with FBC ashes. (1) The best proportion of binding material for FBC bed ash is FBC bed ash: PC fly ash: cement is 0.56:0.24:0.2.The appreciate strength and expansion ratio can be got with this mix proportion.(2) The available proportion for FBC fly ash is FBC fly ash: PC fly: and cement is 0.56:0.24:0.2 or 0.8:0:0.2.(3) The strength and dry density can meet Chinese standard JC 890一2001.The addition of 1% CaCl2 or Na2CO3 can reduce the expansion ratio and do little effect on the strength. But it is not desirable to reduce expansion of FBC ashes.更多还原