Abstract: Forsterite material was prepared with low-grade magnesite and natural silica as raw materials.Effect of the adoption amount of light calcined magnesia powder from low-grade magnesite on lattice constant，microstructure，and room temperature performance of forsterite material was studied.XRD and SEM were used to characterize the sample′s phase composition and microstructure.The lattice constant of the forsterite phase in the sample was analyzed by X′Pert plus software. Structure and properties analysis results showed，forsterite material with forsterite as the main crystal phase could be prepared through solid reaction at high temperature between magnesia in low-grade magnesite and silica from natural silica.With the increase of light calcined magnesia powder from low-grade magnesite，the lattice constant and lattice volume of forsterite phase in the forsterite material presented increasing trend.Meanwhile，the bulk density and cold crush strength of the samples were gradually on the decline, yet the apparent porosity and water absorption of the samples were gradually increasing due to the periclase′s desolvation role in the forsterite material.

Key words: low-grade magnesite, natural silica, forsterite, solid reaction