磷石膏—磷渣基复合胶凝材料强度和水化特性研究

为实现磷石膏、磷渣固废材料的再生利用,提高工业固废的利用率,以磷石膏、磷渣作为主要原料,采用水玻璃、水泥熟料和磷石膏共同激发磷渣活性制备磷石膏—磷渣基复合胶凝材料。 分别探讨磷石膏掺量、水玻璃掺量和磷渣粉磨制度对磷石膏—磷渣基复合胶凝材料强度的影响;并运用 SEM、XRD 分析磷石膏—磷渣基胶凝材料硬化体的微观结构及组成形貌。结果表明:磷石膏掺量低于 50%时,复合胶凝材料各龄期强度与磷石膏掺量成反比;当 m(磷石膏) ∶ m(磷渣) ∶m(熟料)= 20 ∶72 ∶8,水玻璃掺量为 1. 5%时,胶凝材料 28 d 抗压、抗折强度均达到最大值,分别为 43、6. 3 MPa; 较单独粉磨磷渣与水泥熟料而言,混合粉磨制度会产生“微介质效应”,有利于提高复合胶凝材料强度;复合胶凝材料主要水化产物为 C—S—H 凝胶与钙矾石,钙矾石与未溶解的磷石膏作为骨架被生成的 C—S—H 凝胶包裹、充填、交织在一起,形成致密结构;复合胶凝材料用于替代水泥作为矿区充填材料时推荐磷石膏掺量为 20% ~ 40%。

Study on the Strength and Hydration Characteristics of Phosphogypsum-phosphorus Slag Composite Cementitious Material

In order to realize the recycling of phosphogypsum and phosphorus slag solid waste materials,and improve the utilization rate of industrial solid waste,the experiment uses phosphogypsum and phosphorus slag as the main raw materials,along with using water glass,cement clinker and phosphogypsum to jointly stimulate the activity of phosphorus slag for preparing phosphogypsum-phosphorus slag-based composite cementitious materials. The paper discuss the effects of phosphogypsum content,sodium silicate content,and phosphorus slag grinding system on the strength of phosphogypsum-phosphorus slag-based composite cementitious materials,while using SEM and XRD to analyze the microscopic structure and composition morphology of phosphogypsum-phosphorus slag-based cementitious materials hardened. The results showed that when the content of phosphogypsum is less than 50%,the strength of the composite cementing material at each age is inversely proportional to the content of phosphogypsum;when m(phosphogypsum) ∶ m( phosphorus slag) ∶ m( clinker) is 20 ∶ 72 ∶ 8,the sodium silicate content is 1. 5%,the 28 d compressive and flexural strengths of the cementitious material reach the maximum value of 43 and 6. 3 MPa. The grinding system will produce " micro-medium effect" ,which is beneficial to improve the strength of composite cementitious materials. The main hydration products of composite cementitious materials are C—S—H gel and ettringite. The ettringite and undissolved phosphogypsum are formed as the skeleton and was wrapped,filled and interwoven together by C—S—H gel toform a compact structure. When composite cementing materials are used to replace cement as filling materials in mining areas, the recommended phosphogypsum content is 20% ~ 40%.