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Effect of Phosphoric Acid on the Preparation of α-Hemihydrate Gypsum Using Hydrothermal Method.

Authors :
Zhang, Jianwu
Wang, Xiao
Hou, Pengtao
Jin, Biao
Zhang, Xiaoting
Li, Zhixin
Source :
Materials (1996-1944). Sep2023, Vol. 16 Issue 17, p5878. 13p.
Publication Year :
2023

Abstract

The effects of phosphoric acid (H3PO4) in pressurized aqueous solution on the dehydration of CaSO4·2H2O to form α-hemihydrate gypsum (α-HH) phase and the regulation of crystal shape were studied in this paper in order to provide guidance for the low-cost and high-value utilization of phosphogypsum. The results showed that H3PO4 can significantly accelerate the formation rate of the α-HH phase and that it did not participate in the formation of the α-HH phase in the form of eutectic phosphorus during crystalline phase transformation. In terms of crystal shape regulation, H3PO4 can impact the effect of a citric acid crystal regulator on α-HH crystal shape regulation. The more H3PO4 added, the greater the aspect ratio of α-HH. Accordingly, the water consumption and 2 h dry compressive strength of α-HH products were gradually increased and decreased with an increase in H3PO4 content, respectively. Despite this, the compressive strength of α-HH can still meet the requirements of the α20 grade in JC/T 2038-2010 "α High Strength Gypsum" in China when the H3PO4 content was limited to less than 0.4%. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
19961944
Volume :
16
Issue :
17
Database :
Academic Search Index
Journal :
Materials (1996-1944)
Publication Type :
Academic Journal
Accession number :
171857616
Full Text :
https://doi.org/10.3390/ma16175878