活性MgO改性流化床炉底渣-硅灰复合材料的力学性能及产物

Mechanical properties and reaction products of reactive MgO modified circulating fluidized bed combustion slag-silica fume composites

为了充分利用流化床炉底渣,采用活性MgO改性法制备了具有良好力学性能的流化床炉底渣(CFB)-硅灰(SF)复合材料。研究了养护温度、MgO及SF掺量对MgO-CFB-SF复合材料的抗压强度、水化产物及微观结构的影响。初步研究了MgO活性和细度对抗压强度的影响。利用流变仪研究新拌浆体的屈服应力和塑性黏度。利用XRD、TGA、FTIR和SEM对不同龄期试样的反应产物及微观结构进行分析。掺入SF有助于提高该体系的强度,适量的SF(16wt%~20wt%)和20wt%MgO有助于提高MgO-CFB-SF浆体的流动性。常温条件下养护540天的试样微观分析结果表明:产物中的主要相是细小致密的网格状水化硅酸镁(M-S-H)、类水滑石相(Ht)或富铝硅酸盐相(M-S(A)-H)。

In order to make full use of the ground circulating fluidized bed combustion slag（CFB）,reactive MgO,CFB and silica fume（SF）were used to prepare MgO-CFB-SF composites.The good fluidity,high strength and low cost MgO-CFB-SF composites were gained.The effects of curing temperature,SF and MgO dosage on the strength,reaction products and microstructures of MgO-CFB-SF were investigated.The effect of MgO＇s activity and fineness on compressive strength of MgO-CFB-SF was preliminarily studied.The yield stress and plastic viscosity of the MgO-CFB-SF paste were studied by rheometer.The reaction products and microstructure of MgO-CFB-SF with different ages were analyzed by XRD,TGA,FTIR and SEM.It is found the mixing of SF helps to improve the strength of the MgO-CFB-SF composites,and the composite paste with 16 wt%-20 wt% SF and 20 wt% MgO has good flowability.The microanalysis results of MgO-CFB-SF samples maintained for 540 days at room temperature show that the main phase is magnesium silicate hydration（M-S-H）,and hydrotalcite-like phase（Ht）or Al-rich magnesium silicate hydration（M-S（A）-H）.