Cement-Free Binders in Alumina-Magnesia Refractory Castables—A Review

Abstract

To solve the problem of the accelerated deterioration of calcium aluminate (CAC)-bonded alumina-magnesia refractory castables during the secondary refining process, the development of cement-free binders has emerged as one significant research field of castables. The hydration behavior, curing mechanism, and properties of the most recent research on cement-free binders are compared in this paper. The problems and the modification of each binder of recent research are summarized. High-temperature performance of the castables bonded by traditional hydraulic cement-free binders (ρ-Al₂O₃ and activated MgO) is outstanding, explosive spalling resistance of the castables bonded by sol binders (silica sol, alumina sol) is good, and the properties of the castables bonded by novel organic hydratable binder (hydratable magnesium citrate) combine the advantages of these two binders above, but the mid-temperature mechanical strength is low. Furthermore, alumina-magnesia castables bonded by organic-composited inorganic cement-free binders are expected to be a future domain.

Keywords

Cement-free binder / Refractory castables / Hydration process / Gas permeability / High-temperature performance

Acknowledgment

The authors acknowledge Yunqin Gao and Xing Hou, High-Temperature Ceramics Institute of Xi’an University of Architecture and Technology, for their assistance with the preparation and performance test of refractories.

Author Contributions

Conceptualization, L.S., D.D., G.X.; Investigation, L.S., J.C., and G.X.; Writing—Original Draft Preparation, L.S. and Y.F.; Writing—Review & Editing, L.S., D.D., and Y.F.; Supervision, D.D.; Project, D.D. and G.X.; Funding Acquisition, G.X.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable for studies not involving humans.

Funding

This research was funded by the National Natural Science Foundation of China (NO. 52372034, NO. 52272027);Key R&D Project in Shaanxi Province (2023-GHZD-51, 2022GY-421).

5 Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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