Inorganic Chemicals Industry ›› 2024, Vol. 56 ›› Issue (6): 94-101.doi: 10.19964/j.issn.1006-4990.2023-0408

• Environment·Health·Safety • Previous Articles     Next Articles

Effect of high temperature modification of mineral powder and quicklime on properties of phosphogypsum cement based materials

TU Yanping1,2(), BAI Dengxian1,2, CHENG Shukai1,2, XIE Junjie1,2, HUANG Zhiliang3, CHEN Guofu4()   

  1. 1.School of Civil Engineering and Architecture,Wuhan Institute of Technology,Wuhan 430073,China
    2.Hubei Engineering research Center of Green Civil Engineering Materials and Structures,Wuhan 430073,China
    3.School of Materials Science and Engineering,Wuhan Institute of Technology,Wuhan 430074,China
    4.School of Civil Engineering,Guang′an Vocational & Technical College,Guang′an 638500,China
  • Received:2023-08-10 Online:2024-06-10 Published:2024-06-20
  • Contact: CHEN Guofu E-mail:121552188@qq.com;1330250291@qq.com

Abstract:

Due to the inevitable incorporation of impurities in phosphogypsum,its quality is poor,which further hinders the application of phosphogypsum.The effect of quicklime high-temperature modified phosphogypsum on the strength of cement-based materials was explored by using phosphogypsum and Portland cement as raw materials,and then the improvement effect of mineral powder on the defects of insufficient strength and rapid coagulation of high amount phosphogypsum cement-based materials was studied.Finally,XRD and SEM were used to analyze the hydration products of phosphogypsum cement-based materials,and the improvement mechanism of quicklime and mineral powder on the performance of phosphogypsum cement-based materials was revealed.The results showed that quicklime could successfully eliminate acid impurities in phosphogypsum at high temperature,improve the strength of the cementitious material,and taking into account the environmental protection and strength properties,the optimal amount of quicklime was 2%.The addition of mineral powder could further improve the strength of the cementitious material,delay the initial and final setting time of phosphogypsum cement-based material.With the continuous increase of mineral powder content,the strength of the cementitious material showed a trend of first increase and then decreased at 28 d.Taking into account all aspects of performance,the optimal amount of mineral powder was 20%.In addition,after adding mineral powder,the cementitious material generated interlaced hydroxylapatite in the microstructure at 28 d,which was structurally stable and conducive to the development of mechanical properties of phosphogypsum cement-based materials.

Key words: phosphogypsum, quicklime, modification mechanism, mineral powder, cement mortar

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