基于铜渣基铁系草酸盐水泥具有快凝、早强等特性,在高温窑炉修补和核废物固化等领域具有潜在的应用前景。本文在前期铜渣基铁系草酸盐水泥基础性能研究的基础上,系统考察了其在不同温度(150~1000 ℃)热处理条件下性能、物相及结构的衍变。结果表明,自然养护28d时,铜渣基铁系草酸盐水泥抗压强度达55.1 MPa,其物相主要由反应新生成的FeC₂O₄.2H₂O和未完全反应的铁橄榄石相Fe₂SiO₄组成。经不同温度热处理后,力学性能及结构发生规律性变化。当热处理温度高于250℃时,生成的胶凝相物质FeC₂O₄.2H₂O开始热分解,材料结构发生破坏,力学性能下降,至1000 ℃时,抗压强度趋于稳定,约为15MPa。由此可见,铜渣基铁系草酸盐水泥在高温下仍可保持较高的力学性能,具有较好的热稳定性。

Copper slag based ferrous oxalate cement (CS-FOC) has great potential application prospects in the fields of repairment of highStemperature kilns and stabilization/solidification of nuclear wastes due to its properties such as fast-setting and high early age strength. In this study, the evolution of properties, phase compositions and structure of CS-FOC after exposure to elevated temperatures was comprehensively researched on the basis of our preliminary studies. The results showed that the compressive strength can reach 55.1 MPa when naturally cured for 28 days, and it was mainly composed of new-formed ferrous oxalate dihydrate (FeC2O4.2H2O) and unreacted fayalite (Fe2SiO4). The compressive strength and structure of CS-FOC changed regularly after exposure to elevated temperatures. When treated at higher than 250 ℃, the formed FeC2O4.2H2O started to decompose into iron oxide, and the strength decreased because of the destroyed structure. The strength can stably keep at about 15 MPa after exposure to the temperature of 1000 ℃. Thus, CS-FOC has better thermal stability than ordinary Portland cement and remains at higher level compressive strength.

TU528

国家自然科学(22366023); 昆明理工大学分析测试(2023T20130126)