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Influence of crystal modifier on the preparation of α-hemihydrate gypsum from phosphogypsum
HighlightsOriginal phosphogypsum was utilized for the preparation of α-CaSO4·0.5H2O.Semi-dry method process was adopted for the preparation of α-CaSO4·0.5H2O.Low cost, high value-added and met the requirements of Chinese standard of α-CaSO4·0.5H2O were prepared.
AbstractCrystal modifier is an important factor in preparation of α-hemihydrate gypsum (α-CaSO4·0.5H2O) from phosphogypsum (PG). Here, α-CaSO4·0.5H2O was prepared from PG using a semi-dry method. SEM, XRD, XPS were used to explore the effects of one or more crystal modifiers on crystal growth and mechanical properties after hydration and hardening of α-CaSO4·0.5H2O. The results showed that addition of RCOO− can delay the hydration process of α-CaSO4·0.5H2O and improve productivity. Al3+ can be adsorbed selectively on the gypsum crystal surface, inhibiting the crystal growth along axis c, which could alter the speed in all directions and turn the crystal into a short hexahedron pole. But when RCOO− and Al3+ were composited, a superposition effect occurred, resulting in production of a crystal with a smaller length to diameter ratio and more perfect crystal form. When RCOO− and Al3+ were both added in 0.06% level, the flexural and compressive strength of the hardened α-CaSO4·0.5H2O could reach to 6.7 and 25.65MPa, respectively.
Influence of crystal modifier on the preparation of α-hemihydrate gypsum from phosphogypsum
HighlightsOriginal phosphogypsum was utilized for the preparation of α-CaSO4·0.5H2O.Semi-dry method process was adopted for the preparation of α-CaSO4·0.5H2O.Low cost, high value-added and met the requirements of Chinese standard of α-CaSO4·0.5H2O were prepared.
AbstractCrystal modifier is an important factor in preparation of α-hemihydrate gypsum (α-CaSO4·0.5H2O) from phosphogypsum (PG). Here, α-CaSO4·0.5H2O was prepared from PG using a semi-dry method. SEM, XRD, XPS were used to explore the effects of one or more crystal modifiers on crystal growth and mechanical properties after hydration and hardening of α-CaSO4·0.5H2O. The results showed that addition of RCOO− can delay the hydration process of α-CaSO4·0.5H2O and improve productivity. Al3+ can be adsorbed selectively on the gypsum crystal surface, inhibiting the crystal growth along axis c, which could alter the speed in all directions and turn the crystal into a short hexahedron pole. But when RCOO− and Al3+ were composited, a superposition effect occurred, resulting in production of a crystal with a smaller length to diameter ratio and more perfect crystal form. When RCOO− and Al3+ were both added in 0.06% level, the flexural and compressive strength of the hardened α-CaSO4·0.5H2O could reach to 6.7 and 25.65MPa, respectively.
Influence of crystal modifier on the preparation of α-hemihydrate gypsum from phosphogypsum
Duan, Zhengyang (author) / Li, Jianxi (author) / Li, Tianguo (author) / Zheng, Shurui (author) / Han, Weiming (author) / Geng, Qingyu (author) / Guo, Huibin (author)
Construction and Building Materials ; 133 ; 323-329
2016-12-16
7 pages
Article (Journal)
Electronic Resource
English
Influence of crystal modifier on the preparation of α-hemihydrate gypsum from phosphogypsum
| British Library Online Contents | 2017
Influence of crystal modifier on the preparation of [alpha]-hemihydrate gypsum from phosphogypsum
| Online Contents | 2017
Influence of crystal modifier on the preparation of α-hemihydrate gypsum from phosphogypsum
| British Library Online Contents | 2017
Influence of crystal modifier on the preparation of α-hemihydrate gypsum from phosphogypsum
| Online Contents | 2017