Pre-packaged magnesium alloy sacrificial anode MG-8 with backfill for pipeline cathodic protection.

Sacrificial magnesium anodes are electrochemical protection devices widely used in the field of metal corrosion prevention. The core principle involves utilizing the more reactive nature of magnesium metal compared to the protected metal, continuously "sacrificing" itself through dissolution to release electrons, thereby inhibiting the corrosion of the protected metal.

When used in soil, magnesium alloy sacrificial anodes are typically processed into blocks or rods and placed in backfill bags. They are buried vertically or horizontally at a certain distance from the pipeline (the spacing is determined based on design and site conditions, specifically referring to the design drawings and the standardGB/T21448-2008"Technical Specification for Cathodic Protection of Buried Steel Pipelines"). The cable attached to the anode is welded to the protected structure using thermite welding. The welding points are treated with anti-corrosion materials such as epoxy resin to the same level as the original anti-corrosion coating. The anode burial position should be level with the pipeline, and the distance from the pipeline should be approximately1-2meters.

The backfill material is a mixture of gypsum powder, industrial magnesium sulfate, and bentonite mixed in standard proportions. Before burial, the anode along with the backfill material should be soaked in clean water for about1hour, with the standard being that all backfill material is fully saturated. Alternatively, the anode bag can be placed in the anode pit and watered until fully saturated.