Processing flow of quartz sand filter media in Beijing:

1. Scrubbing and desliming. Scrubbing refers to the removal of thin-film iron, adhesive, and muddy impurity minerals from the surface of quartz sand, as well as further crushing of unseparated mineral aggregates, through mechanical force and the abrasive action between sand particles. This is followed by classification operations to further enhance the purification of quartz sand. Currently, the main methods include rod mill scrubbing and mechanical scrubbing. The primary factors affecting the scrubbing effect are the structural characteristics and configuration of the scrubbing equipment, while secondary factors include scrubbing time and scrubbing concentration (the scrubbing concentration is generally recommended to be 50%–60%).

2. Magnetic separation. Magnetic separation is primarily used to remove magnetic minerals from quartz sand. For example, weakly magnetic minerals such as hematite, limonite, and biotite can be removed using high-intensity magnetic separators, while strongly magnetic minerals like magnetite can be removed using low-intensity magnetic separators.

3. Flotation. Flotation is used to remove impurities such as feldspar and mica from quartz sand that cannot be eliminated by magnetic separation, further enhancing its purity.

4. Acid leaching. Acid leaching takes advantage of the fact that quartz is insoluble in acids (except hydrofluoric acid), while other impurity minerals can be dissolved by acid solutions, thereby enabling further purification of quartz.

5. Microbial leaching. This refers to the use of microorganisms to remove the film iron or disseminated iron on the surface of quartz sand particles, a newly developed iron removal technology.