Materials In this study, we provided a simple method to extract the silicate species from the waste silica‐containing molding compounds from the semiconducting industry. Methods Recycled sodium silicate solution was obtained from alkaline extraction of the silica fillers in the waste molding compounds and dried and redissolved in appropriate amount of water. Results Porous silica of high surface area (>500 m2g−1) and tunable pore size (1.5–5.0 nm) could be feasibly synthesized by using the recycled sodium silicate as silica source and nature‐friendly homopolymer polyethylene glycol (PEG) as an organic template. The pore size of the PEG‐templating silicas was made tunable by hydrothermal treatment at different pH. Conclusion To reduce the emission of CO2 gas from the removal of the PEG template, porous silica with a large surface area has been prepared at a low PEG/sodium silicate weight ratio of 1/20. This study extracted silicate species from waste silica‐containing molding compounds in the semiconductor industry. Using this recycled sodium silicate as the silica source and eco‐friendly polyethylene glycol (PEG) as an organic template, porous silica with a high surface area (>500 m2g−1) and adjustable pore size (1.5–5.0 nm) can be synthesized.