Effect of slurry concentration on the quality of calcium sulphate hemihydrate in a magnetized water system

Abstract

Multifunctional calcium sulphate hemihydrate (HH) whiskers were prepared hydrothermally in magnetized water using raw gypsum. The hydrothermal products were characterized by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The results showed that the slurry concentration considerably affected the quality of the hydrothermal HH formed in the magnetized water because the slurry concentration affected the viscosity of the raw gypsum slurry. When the slurry concentration was 6.0%, the slurry had a suitable viscosity, which was conducive to the dissolution of the raw gypsum. The abundance of solution-phase Ca2+ and SO42− ions was the greatest, thus increasing the driving force for the CaSO4·2H2O (DH)-to-HH phase transition.