Investigation of sodium alginate as a candidate retarder of magnesium phosphate cement: Hydration properties and its retarding mechanism. Issue 20 (15th October 2022)

• Record Type: Journal Article
• Authors: Liu, Runqing; Fang, Bodong; Zhang, Guanhua; Guo, Jinbo; Yang, Yuanquan
• Is Part Of: Ceramics international. Volume 48:Issue 20(2022)
• Page Start: 30846
• Page End: 30852
• Publication Date: 2022-10-15
• Subjects: Magnesium potassium phosphate cement -- Sodium alginate -- Hydration -- Suspension -- Retarder; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.07.038
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: This work investigated the effect of sodium alginate on the hydration properties of magnesium potassium phosphate cement (MKPC) suspension with a high w/c ratio, and explored its retarding mechanism. At w/c = 10, hydration of MKPC presented a mult-step process, specifically, KMg2 H(PO4 )2 15H2 O and possibly MgHPO4· 7H2 O first precipitate, then decomposed to struvite-k. As sodium alginate was added, Na2 HPO4 12H2 O and KMg2 H(PO4 )2 15H2 O precipitated at the initial stage, and then destabilized afterwards. Sodium alginate could delay dissolution of KMg2 H(PO4 )2 15H2 O as well as precipitation of struvite-k. Moreover, sodium alginate tends to transform to alginic acid at low pH, and left a large number of Na + ions, leading to precipitation of Na2 HPO4 12H2 O. The alginic acid is difficult to dissolve at low pH, which limited its effect on extending the setting time of MKPC further.