A low-cost and simple approach to prepare mullite ceramics via DCC-HVCI using ammonia as dispersant. Issue 17 (1st December 2018)

• Record Type: Journal Article
• Authors: Chen, Peng; Wu, Jia-Min; Liu, Rong-Zhen; Chen, An-Nan; Chen, Ying; Shi, Yu-Sheng; Li, Chen-Hui; Zhang, Kuang; Cui, Deng; Wang, Yong-Jun
• Is Part Of: Ceramics international. Volume 44:Issue 17(2018)
• Page Start: 21779
• Page End: 21785
• Publication Date: 2018-12-01
• Subjects: Coal-series kaolin -- DCC-HVCI -- Ammonia -- Mullite ceramics; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.08.280
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Coal-series kaolin (CSK) is a tremendous solid waste in China, but also an ideal precursor for mullite. In this study, a low-cost and simple approach to fabricate mullite ceramics via direct coagulation casting (DCC) is reported. Ammonia water was found capable of acting as both pH regulator and dispersant in CSK suspension due to the alkali activation of CSK powder. With 0.30 wt% ammonia water added, CSK suspension was obtained with a solid loading of 50 vol% and viscosity of 41.12 mPa·s. The suspension became coagulable by adding 3 mg/mL of Ca(IO3 )2 ·6H2 O and 2 wt% glycerol diacetate (GDA), and a crack-free green body was prepared by heating in water bath at 70 ℃ for 30 min. The effects of sintering temperature on the properties of sintered samples were studied. After sintered at the optimized temperature (1550 ℃) for 4 h, mullite ceramics with complex shapes were obtained with a bulk density of 2.65 ± 0.02 g/cm 3 and a flexural strength of 101.32 ± 9.91 MPa.