Solidification/stabilisation behaviours of Zn 2+ in magnesium potassium phosphate cement: Experiments and density functional theory study.

The solidification/stabilisation behaviours of Zn ²⁺ in magnesium potassium phosphate cement (MKPC) have not been thoroughly investigated. Herein, a series of experiments and a detailed density functional theory (DFT) study were conducted to investigate the solidification/stabilisation behaviours of Zn ²⁺ in MKPC. The results showed that the compressive strength of MKPC reduced with the addition of Zn ²⁺ because the formation of MgKPO ₄ ·6H ₂ O (the main hydration product in MKPC) was delayed with the addition of Zn ²⁺ , as discovered by the crystal characteristics, and because Zn ²⁺ exhibited a lower binding energy in MgKPO ₄ ·6H ₂ O compared to Mg ²⁺ , as revealed by DFT results. Additonally, Zn ²⁺ had little influence on the structure of MgKPO ₄ ·6H ₂ O, and Zn ²⁺ existed in MKPC as the formation of Zn ₂ (OH)PO ₄ , which was decomposed in the range of around 190-350 °C. Moreover, there were a lot of well-crystallised tabular hydration products before the addition of Zn ²⁺ , but the matrix was comprised of irregular prism crystals after adding Zn ²⁺ . Furthermore, the leaching toxicity of Zn ²⁺ of MKPC was much smaller than the requirements of Chinese and European standards.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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