Hydration mechanism of hydrated magnesium citrate: The effects of MgCl ₂

Abstract In this study, the evolutions of kinetic parameters, such as hydration temperature, pH, and electrical conductivity, were observed to investigate the hydration mechanism of hydrated magnesium citrate (HMC). Additionally, the effects of MgCl 2 on the hydration behavior of HMC and the working performance of its bonded castables were also investigated. The results show that the hydration mechanism of HMC is dissolution–precipitation, and its hydration product is magnesium citrate tetrahydrate [Mg(H 2 O) 6 ] [MgC 6 H 5 O 7 (H 2 O)n] 2 ∙(8‐2n)H 2 O. The hydration process of HMC is controlled by the concentration of the C 6 H 6 O 7 2− ions. MgCl 2 could inhibit the ionization of HMC, thereby delaying the hydration progress of HMC. The second exothermic peak was delayed from 1 to 4.8 h with increased MgCl 2 content to 1.0 wt.%. The working performance of HMC‐bonded castables could be improved by adding MgCl 2 . After adding MgCl 2 , the setting time, flow value, and cold modulus of rupture of HMC‐bonded castables increased by 26.7%, 25.2%, and 8.8%, respectively, while the porosity decreased by 12%.