A nontoxic, water-soluble copolymer consisting of isobutylene and maleic anhydride (PIBM) was used as both dispersant and gelling agent to mold MgAl2O4 green body by gelcasting at room temperature in air. In this paper, MgAl2O4 slurries with solid loadings from 43 vol% to 50 vol% were prepared by adding PIBM. The rheological properties of the slurries were investigated. As the solid loadings increased from 43 vol% to 50 vol%, the linear shrinkage in the drying and pre-sintering process decreased from 6.9% to 2.8% and from 16.0% to 14.7%, respectively. The bending strength of the green body with 50 vol% solid loading can reach 2.62 MPa. The in-line transmission of the MgAl2O4 ceramics gradually increased from 61% to 86.9% (1100 nm) with the solid loadings increasing. (C) 2015 Elsevier B.V. All rights reserved.