During use, silica gel adsorbs water vapor or other organic substances from the surrounding medium, leading to a decline in its adsorption capacity; it can be regenerated and reused.

I. Regeneration of Silica Gel After Adsorbing Water Vapor
After silica gel has adsorbed moisture, the water can be removed by thermal desorption. Heating methods include electric furnaces, waste‑heat recovery from flue gases, and hot‑air drying, among others. The desorption temperature should ideally be maintained between 120 and 180°C; for blue‑indicator silica gel, the optimal range is 100–120°C. When regenerating industrial‑grade silica gel, the maximum operating temperature must not exceed the following limits:
The temperature of coarse-pore silica gel shall not exceed 600°C.
silica gel with fine pores shall not exceed 200°C.
The blue gel indicator must not exceed 120°C.
The silica-alumina gel shall not exceed 350°C.
After regeneration, the silica gel can be reused once its moisture content is typically maintained at 2% or lower.

II. Regeneration of silica gel after adsorption of organic impurities:
1. Calcination: For coarse-pored silica gel, place it in a calcination furnace and gradually heat it to 500–600°C; after approximately 6–8 hours, the gel particles will turn white or yellowish-brown. For fine-pored silica gel, the calcination temperature should not exceed 200°C.
2. Washing method: After the silica gel has been saturated by adsorption in saturated water vapor, it is immersed in hot water for rinsing; detergents may also be used to remove waste oil or other organic impurities. Following rinsing with clean water, the material is dried and dehydrated.
3. Solvent elution method: Depending on the type of organic compounds adsorbed by the silica gel, an appropriate solvent is selected to dissolve and elute the adsorbed organics. The silica gel is then heated to remove the solvent.

III. Considerations for silica gel Regeneration
1. During drying and regeneration, care should be taken to gradually increase the temperature to prevent rapid drying from causing the polymer particles to rupture and reducing the recovery rate.
2. During the calcination and regeneration of silica gel, excessively high temperatures can alter its pore structure, significantly reducing its adsorption performance and compromising its practical value. For blue‑gel indicators or color‑changing silica gel, the desorption‑regeneration temperature should not exceed 120°C; otherwise, the color‑developing agent may gradually oxidize, leading to a loss of its color‑changing capability.
3. Regenerated silica gel should generally be screened to remove fine particles, ensuring uniform particle size.