Rough-hole silica gel, also known as C-type silica gel, is a type of silica gel, and it is a highly active adsorption material. It is an amorphous material and its chemical formula is mSiO2·nH2O. It is insoluble in water and any solvent, non-toxic and odorless, chemically stable, and does not react with any substances except strong alkali and hydrofluoric acid. The chemical composition and physical structure of the crude-porous silica gel determine that it has many other similar materials that are difficult to substitute: high adsorption performance, good thermal stability, chemical stability, and high mechanical strength. The coarse-pored silica gel has a white appearance with three types of products: blocky, spherical and micro-spherical. The coarse-pore spherical silica gel is mainly used for gas purifiers, desiccants, and acid scavengers for insulating oils; coarse pore silica gel is mainly used for catalyst carriers, desiccants, gas and liquid purifiers.