添加剂对飞灰基地聚合物固化体性能的影响

Influence of additives on performance of fly ash-based geopolymer

为解决当飞灰掺入量较大时,飞灰基地聚合物固化体出现的体积膨胀、成型效果差和浆砂快凝等问题,在地聚合物固化飞灰时分别掺入水泥、沸石和偏磷酸钠三种添加剂,考察掺入水泥、沸石和偏磷酸钠对飞灰基地聚合物固化体抗压强度和重金属浸出质量浓度的影响.结果表明:水泥掺量在2%时,固化体的抗压强度达到33.00MPa,并且较好地缓解了固化体膨胀问题;沸石掺量在2%时,固化体的抗压强度得到明显的改善,提高效率达17.79%;掺加2%偏磷酸钠可以有效地解决浆砂的快凝问题,并且将飞灰最大掺量提高至60%;同时掺入添加剂之后,重金属Pb,Zn,Cu,Cr和Cd的浸出质量浓度都很低,重金属被很好地包容在固化体中,表现出良好的浸出安全性.

In order to solve the problems of Municipal solid waste incineration （MSWI） fly ashbased geopolymer such as volume expansion,poor molding effect and fast setting problem which was caused by adding large quantities of fly ash,this article explored the fly ash-based geopolymer added with three additives including cement、zeolite and sodium metaphosphate.Compressive strength and leaching concentration of heavy metals of geopolymers were investigated.Results showed that the compressive strength of the fly ash-based geopolymer mixing with 2％ cement could reach to 33.00 MPa,and may halt the volume expansion.Moreover,adding 2％ zeolite improved the compressive strength of the fly ash-based geopolymer significantly with the efficiency of 17.79％.Furthermore,mixing with 2％ sodium metaphosphate could effectively solve the fast setting problem,and improved the maximum containment of the fly ash to 60％.In addition,after adding additives,the leaching concentration of Pb,Zn,Cu,Cr and Cd were very low,indicating that the heavy metals were greatly held in geopolymer,exhibiting good leaching security.