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Effects of calcium monohydrogenphosphate on the morphology of calcium sulfate whisker by hydrothermal synthesis
Author(s) -
Lü Pengfei,
Fei Dejun,
Dang Yagu
Publication year - 2014
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.22037
Subject(s) - phosphogypsum , whisker , hydrothermal circulation , scanning electron microscope , morphology (biology) , hydrothermal synthesis , materials science , chemical engineering , seed crystal , calcium , crystal growth , mineralogy , nuclear chemistry , nanotechnology , chemistry , crystallography , metallurgy , composite material , single crystal , geology , raw material , organic chemistry , paleontology , engineering
In this paper, the factors related to the morphology of calcium sulfate whisker (CSW) are discussed. Most attention was devoted to the influence of co‐crystallized phosphorus in phosphogypsum—existing in the form of CaHPO 4 · 2H 2 O—on the crystal growth, which was ignored in the preparation of CSW from phosphogypsum in previous research. Methods including X‐ray powder diffraction and scanning electron microscopy were performed to characterize the resultant crystals. The CSWs with uniform morphology were prepared by hydrothermal synthesis with commercial CaSO 4 · 2H 2 O. However, the productions from the pretreatment phosphogypsum by hydrothermal synthesis appeared as irregular crystals with a small length to width ratio, and whisk‐broom‐like crystals were common. The influence of CaHPO 4 · 2H 2 O on the growth of CSW has also been studied. The results showed that CaHPO 4 · 2H 2 O can promote the formation of needle‐like crystals and whisk‐broom‐like crystals at hydration condition. In order to improve the morphology of CSW in a CaSO 4 · 2H 2 O‐CaHPO 4 · 2H 2 O system, substantive condition experiments were carried out, and it finally revealed that Fe 3+ was useful for the well‐developed CSW.