Effects of phosphoric acid and phosphates on magnesium oxysulfate cement

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	Effects of phosphoric acid and phosphates on magnesium oxysulfate cement
	Wu, Chengyou 1,2; Yu, Hongfa 1,3,4; Zhang, Huifang 1,2; Dong, Jinmei 1,2; Wen, Jing 1,2; Tan, Yongshan 1,2
	2015-04-01
发表期刊	MATERIALS AND STRUCTURES
卷号	48 期号:4 页码:907-917
关键词	Magnesium Oxysulfate Cement Compressive Strength Water Resistance Phosphate Phase Composition
摘要	Magnesium oxysulfate (MOS) cement is a promising material for fire-proofing and insulation applications. Here, we have studied the effects of phosphoric acid and phosphates (H3PO4, KH2PO4, K3PO4 and K2HPO4) on the setting time, mechanical strength and water resistance of MOS cement. X-ray diffraction was used to examine phase composition, and analytical reagents were used to prepare samples of the new phase found so that it would be examined by chemical and thermogravimetric analyses. Adding phosphoric acid and phosphates can extend the setting time and improve the compressive strength and water resistance of MOS cement by changing the hydration process of MgO and the phase composition. A new subsulfate phase 5Mg(OH)(2)center dot MgSO4 center dot 7H(2)O (517 phase) is formed, which is needle-like and insoluble in water. Phosphoric acid or phosphates ionize in solution to form H2PO4 (-), HPO4 (2-) and/or PO4 (3-), and these anions adsorb onto [Mg(OH)(H2O) (x) ](+) to inhibit the formation of Mg(OH)(2) and further promote the generation of a new magnesium subsulfate phase, leading to the compact structure, high mechanical strength and good water resistance of MOS cement. The improvement produced by adding phosphoric acid or phosphates to MOS cement follows the order of H3PO4 = KH2PO4 a parts per thousand << K2HPO4 > K3PO4.
语种	英语
引用统计
文献类型	期刊论文
条目标识符	http://ir.isl.ac.cn/handle/363002/5561
专题	青海盐湖研究所知识仓储中国科学院青海盐湖研究所
作者单位	1.Chinese Acad Sci, Qinghai Inst Salt Lakes, Xining 810008, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Nanjing Univ Aeronaut & Astronaut, Dept Civil Engn, Nanjing 210016, Peoples R China 4.Qinghai Univ, Dept Civil Engn, Xining 810008, Peoples R China
推荐引用方式 GB/T 7714	Wu, Chengyou,Yu, Hongfa,Zhang, Huifang,et al. Effects of phosphoric acid and phosphates on magnesium oxysulfate cement[J]. MATERIALS AND STRUCTURES,2015,48(4):907-917.
APA	Wu, Chengyou,Yu, Hongfa,Zhang, Huifang,Dong, Jinmei,Wen, Jing,&Tan, Yongshan.(2015).Effects of phosphoric acid and phosphates on magnesium oxysulfate cement.MATERIALS AND STRUCTURES,48(4),907-917.
MLA	Wu, Chengyou,et al."Effects of phosphoric acid and phosphates on magnesium oxysulfate cement".MATERIALS AND STRUCTURES 48.4(2015):907-917.