铜渣基磷酸盐胶凝材料的力学性能与微观结构

Mechanical Properties and Microstructure of Copper Slag-Based Phosphate Cementitious Materials

磷酸盐胶凝材料力学性能好,制备工艺简单,为资源化利用铜渣提供了新的途径。本文以铜渣和磷酸二氢钠(NaH_(2)PO_(4))为原料制备了磷酸盐胶凝材料,采用电子万能试验机、X射线粉末衍射仪及扫描电子显微镜研究了原料配合比和养护条件对铜渣基磷酸盐胶凝材料抗压强度、物相和微观形貌的影响,并采用同步热分析仪考察了磷酸盐胶凝材料的热稳定性。结果表明,原料配合比对磷酸盐胶凝材料的力学性能和微观结构有重要影响,适当提高养护温度有利于强度发展。当NaH_(2)PO_(4)/铜渣质量比为0.30、水/(NaH_(2)PO_(4)+铜渣)质量比为0.15、60℃下养护7 d时,铜渣基磷酸盐胶凝材料抗压强度高达54.70 MPa。铜渣基磷酸盐胶凝材料优异的力学性能源自铜渣中铁橄榄石(Fe_(2)SiO_(4))与NaH_(2)PO_(4)反应生成的致密无定形结构相。铜渣基磷酸盐胶凝材料热稳定性较好,空气气氛下467℃开始被氧化分解,无定形结构相发生相转变。

Phosphate cementitious materials have good mechanical properties,and simple preparation process,which provide a new way for resource utilization of copper slag.Phosphate cementitious materials were prepared using copper slag and sodium dihydrogen phosphate(NaH_(2)PO_(4))as raw materials.And the effects of raw material mix ratio and curing conditions on compressive strength,phase and microstructure of copper slag-based phosphate cementitious materials were studied by universal testing machine,X-ray powder diffractometer and scanning electron microscope.Besides,the thermal stability of copper slag-based phosphate cementitious materials was also investigated by simultaneous thermal analyzer.The results show that raw material mix ratio has an important influence on mechanical properties and microstructure of phosphate cementitious materials.And appropriately increasing the curing temperature is conducive to strength development.When the mass ratio of NaH_(2)PO_(4)to copper slag is 0.30,the mass ratio of water to NaH_(2)PO_(4)and copper slag is 0.15,and the curing temperature is 60℃,the 7 d compressive strength of copper slag-based phosphate cementitious materials is as high as 54.70 MPa.The excellent mechanical properties are due to the dense amorphous phase formed by the reaction of fayalite(Fe_(2)SiO_(4))in copper slag with NaH_(2)PO_(4).Furthermore,the copper slag-based phosphate cementitious materials have good thermal stability.It begins to be oxidized and decomposed at 467℃under air atmosphere,and the amorphous structure phase undergoes phase transition.