工业固废耦合磷石膏制备胶凝材料试验

Experiment on Preparation of Phosphogypsum Cementitious Materials with Industrial Waste

以原状磷石膏、矿粉、水泥熟料等为原料制备磷石膏基复合胶凝材料,考察各组成材料掺量、减水剂用量与外加剂配比等因素对胶凝材料凝结时间与抗压强度的影响,并对产物进行X射线衍射(XRD)、扫描电子显微镜(SEM)分析。结果表明,由磷石膏、矿粉、粉煤灰所组成的复合材料,在水泥碱性环境激发下,水合产物的初凝时间可控制在260 min以内,终凝时间在360 min以内;C30磷石膏基混凝土7 d抗压强度大于26 MPa;磷石膏掺量超过30%时,抗压强度迅速下降;矿粉与粉煤灰的耦合使用,能缩短凝结时间,增强材料力学性能;在水玻璃与聚合铝盐的共同作用下,胶凝材料内部存在大量水化硅酸钙(C-S-H)凝胶骨架和部分纤维状、针状钙矾石,形成具有较高强度的致密磷石膏基复合体。

The phosphogypsum-based cementitious material is prepared by original phosphogypsum,mineral powder,cement clinker.The influence of the dosage of each component material,the dosage of water reducing agent and the ratio of admixture on the setting time and compressive strength of the prepared material is mainly investigated.The products were analyzed by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results show that under the excitation of cement alkaline environment,the initial setting time and final setting time of the hydration product can be controlled within 260 min and 360 min.The 7 d compressive strength of C30 phosphogypsum-based concrete is greater than 26 MPa.When the phosphogypsum content exceeds 30%,the compressive strength decreases rapidly;The coupling use of mineral powder and fly ash can shorten the setting time and enhance the mechanical properties of the material;Under the interaction of sodium silicate and polyaluminum salt,a large number of C-S-H gel skeletons and part of fibrous and needle-like ettringite exist in the cementitious material.In addition,dense phosphogypsum-based complexes with high strength are formed.