Effect of iron on the preparation of iron-rich calcium sulfoatablluminate cement using gypsum as the sole calcium oxide source and its incorporation into mineral phases. (5th July 2021)

• Record Type: Journal Article
• Authors: Wu, Shuang; Yao, Xingliang; Ren, Changzai; Yao, Yonggang; Zhang, Chao; Wu, Changliang; Wang, Wenlong
• Is Part Of: Construction & building materials. Volume 290(2021)
• Publication Date: 2021-07-05
• Subjects: Iron-rich calcium sulfoaluminate cement -- Phase composition -- Incorporation -- Iron-bearing ye'elimite -- Industrial solid waste; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.123214
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Iron-rich CSA cement was produced using gypsum as CaO and SO3 sources. Effect of iron on phase composition and hydration of IR-CSA cement was shown. Incorporation of iron in ye'elimite, belite and ferrous phase was studied. Abstract: Iron-rich calcium sulfoaluminate (IR-CSA) cement is a low-carbon cement that contains small amount of aluminum. In this study, IR-CSA cement preparation method using gypsum as the source of calcium oxide was developed. The effects of iron on the decomposition of gypsum, formation of phases, microstructure of the clinker, and hydration of cement paste were investigated. The results indicated that the decomposition of gypsum and the formation of the target phase were first slightly promoted and then hindered when the iron content in the raw material increased. The presence of iron enhanced the growth of crystal grains and densification of the microstructure in the clinker. The early hydration behavior of IR-CSA cement mainly depended on the hydration of the iron-bearing ye'elimite and ferrous phases. Furthermore, the incorporation of iron into mineral phases was studied. The maximum incorporation content of Fe2 O3 in ye'elimite and belite phase reached 19.36 wt%, expressed as C4 A2.61 F0.39 S -, and 2.83 wt%, respectively. The chemical composition of the ferrous phase was similar to that of C4 AF, and its mineral phases were C2 F, C6 AF2, C4 AF, and C6 A2 F from the center to the edge. Finally, the feasibility of preparing IR-CSA cement using phosphogypsum as the sole calcium oxide source was evaluated for engineering applications. This unique preparation method reduces the use of aluminum in raw materials and thus promotes recycling of iron-containing or low-aluminum-containing industrial solid waste materials.