Magnesium-based cementitious material, preparation method and application thereof

A preparation method for a magnesium-based cementitious material, comprising the following steps:

• mixing magnesite and sandstone to obtain a mixture, and processing the mixture by molding to obtain a molded raw meal;
• wherein the magnesite is provided with CaO, SiO2, Al2O3, Fe2O3 and MgO, a mass percentage of the CaO is less than 5%, a mass percentage of SiO2 is less than 5%, a mass percentage of Al2O3 is less than 5%, a mass percentage of Fe2O3 is less than 7%, a mass percentage of MgO is between 37% and 50%;
• the sandstone is provided with SiO2, CaO, Al2O3, and Fe2O3, a mass percentage of SiO2 is greater than 70%, a mass percentage of CaO is less than 10%, a mass percentage of Al2O3 is less than 10%, and a mass percentage of Fe2O3 is less than 5%;
• and a mass ratio of the magnesite to the sandstone is 65-75:25-35;
• calcining the molded raw meal to obtain a clinker;
• mixing and shaping the clinker with water to obtain a primary cementitious material;
• subjecting the primary cementitious material to carbonization curing to obtain the magnesium-based cementitious material.