Influence of disodium hydrogen phosphate dodecahydrate on hydrothermal formation of hemihydrate calcium sulfate whiskers--颗粒学报PARTICUOLOGY

Han, Q., Luo, K., Li, H., & Xiang, L. (2014). Influence of disodium hydrogen phosphate dodecahydrate on hydrothermal formation of hemihydrate calcium sulfate whiskers. Particuology, 17, 131–135. https://doi.org/10.1016/j.partic.2013.10.002

Influence of disodium hydrogen phosphate dodecahydrate on hydrothermal formation of hemihydrate calcium sulfate whiskers

Qing Han ^{a b}, Kangbi Luo^a *, Huping Li ^a, Lan Xiang ^b

a College of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, China
b Department of Chemical Engineering, Tsinghua University, Beijing 100084, China

10.1016/j.partic.2013.10.002

Volume 17, December 2014, Pages 131-135

Received 17 May 2013, Revised 30 September 2013, Accepted 12 October 2013, Available online 12 December 2013.

E-mail: luokangbi@126.com

Highlights

• High-aspect-ratios CaSO₄·0.5H₂O were synthesized via a Na₂HPO₄·12H₂O-assisted hydrothermal method.

• High super-saturation achieved in the presence of Na₂HPO₄·12H₂O favored formation of CaSO₄·0.5H₂O.

• Na₂HPO₄·12H₂O promoted formation of CaSO₄·0.5H₂O with thinner diameter and shorter length.

Abstract

The influence of Na₂HPO₄·12H₂O on the hydrothermal formation of hemihydrate calcium sulfate (CaSO₄·0.5H₂O) whiskers from dihydrate calcium sulfate (CaSO₄·2H₂O) at 135 °C was investigated. Experimental results indicate that the addition of phosphorus accelerates the hydrothermal conversion of CaSO₄·2H₂O to CaSO₄·0.5H₂O via the formation of Ca₃(PO₄)₂ and produces CaSO₄·0.5H₂O whiskers with thinner diameters and shorter lengths. Compared with the blank experiment without Na₂HPO₄·12H₂O, the existence of minor amounts (8.65 × 10−4–4.36 × 10−3 mol/L) of Na₂HPO₄·12H₂O led to a decrease in the diameter of CaSO₄·0.5H₂O whiskers from 1.0–10.0 to 0.5–2.0 μm and lengths from 70–300 to 50–200 μm.

Graphical abstract

Keywords

Calcium sulfate whiskers; Morphology control; Phosphorus; Hydrothermal technology

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