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

Abstract

Abstract: 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 (NaH₂PO₄) 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 NaH₂PO₄ to copper slag is 0.30, the mass ratio of water to NaH₂PO₄ 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 (Fe₂SiO₄) in copper slag with NaH₂PO₄. 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.

Key words: phosphate cementitious material, copper slag, NaH₂PO₄, mechanical property, microstructure, thermal stability

CLC Number:

TQ177

XUE Xingyong, HAN Yaocong, SU Qiaoqiao, XU Mengxue, CUI Xuemin. Mechanical Properties and Microstructure of Copper Slag-Based Phosphate Cementitious Materials[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2023, 42(5): 1750-1757.

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