Influences of different bischofite on the properties of magnesium oxychloride cement

In recent years, magnesium oxychloride cement (MOC) has been widely used in the field of building materials. As the main raw material in MOC, bischofite plays an important role in the composition, performance, and cost of MOC. This work systematically investigated the influence of salt lake/marine bischofite on the properties of MOC pastes, and a series of tests on the compressive strength , water resistance, reaction product composition, thermal stability, and microstructure of the MOC pastes was carried out. The results indicated that salt lake bischofite had lower content of impurity ions than marine bischofite, which endowed salt lake bischofite-based MOC with better mechanical strength, thermal stability, and microstructure than marine bischofite-based MOC. In addition, the anions in bischofite were the leading factor in the phase composition difference of MOC, and the dissolution rate of the cations was related to the Coulombic forces of the ions. • Influence of salt lake/marine bischofite on the properties of MOC were investigated. • The salt lake bischofite MOC exhibit better mechanical strength compared to the marine bischofite MOC. • The anions in bischofite were the leading factor in the phase composition differences of MOC. • The dissolution rate of the cations in the MOC was related to the coulombic forces of the ions. • An appropriate content of foreign ions in bischofite was beneficial to the compressive strength.