循环流化床脱硫灰地聚物试验研究

Experimental Study on Circulating Fluidized Bed Desulfurization Ash Geopolymer

探讨了标准养护条件下水胶比、碱激发剂掺量、水玻璃模数对CFB脱硫灰地聚物砂浆强度的影响,进而分析了不同养护制度对CFB脱硫灰地聚物砂浆强度的影响。结果表明,标准养护条件下,随水胶比的增加强度降低,激发剂掺量32%时强度最高,水玻璃模数在1.5时可获得最大强度,标准养护的各龄期强度均大于自然养护的强度,14 d以后强度差距减少。蒸汽养护温度80℃时各龄期的强度都是最高的,超过80℃后,蒸汽养护时间超过8 h后延长养护时间对强度的增长贡献不大,提高蒸汽养护温度对早期强度的提升作用更大。80℃蒸气养护16 h后标准养护,CFB脱硫灰地聚物砂浆3 d抗压、抗折强度分别达到38.7 MPa和7.7 MPa,28 d抗压、抗折强度分别达到41.3 MPa和9.0 MPa。XRD和SEM分析结果显示,CFB脱硫灰经碱激发后,石英晶体结构被破坏,石灰和硬石膏均参与反应,形成大量胶凝状产物且穿插有较多的针棒状水化硫铝酸钙结晶。

Under standard curing conditions,the influences of water binder ratio,alkali activator content and water glass modulus on the strength of CFB desulfurization ash geopolymer mortar were discussed,and then the influences of different curing systems on the strength of CFB desulfurization ash geopolymer mortar were analyzed.The experimental results show that under the standard curing condition,the strength decreases with the increase of water binder ratio,the strength is the highest when the content of activator is 32%,and the maximum strength can be obtained when the modulus of water glass is 1.5.The strength of each age of standard curing is higher than that of natural curing,and the strength gap between standard and natural curing decreases after 14 d.The strength of each age is the highest when the steam curing temperature is 80℃,and when the curing temperature is over 80℃,the longer steaming curing time than 8 h can not improve strength.The increase of the steam curing temperature has a greater effect on the early strength.After 16 h of steam curing at 80℃,the compressive strength and flexural strength of CFB desulfurization ash geopolymer mortar reach 38.7 MPa and 7.7 MPa respectively in 3 d,and 41.3 MPa and 9.0 MPa respectively in 28 d.XRD and SEM analysis show that the crystal structure of quartz is destroyed after the CFB desulfurization ash is excited by alkali,and both lime and anhydrite participated in the reaction,forming a large number of gelatinous products and interspersing with more needles and rods like hydrated calcium sulphoaluminate crystals.