Galvanic Backfill

Galvanic backfill is used with either magnesium or zinc sacrificial anodes to provide an environment which is conductive for anode dissolution.

The chemical backfill helps to retain moisture around the anode, lowers the anode-to-earth resistance, thus ensuring good contact between the anode and soil and providing a uniform environment that reduces self-consumption of the anode.

The typical galvanic backfill mixture composition consists of:

  • Benjamin Franklin Gypsum: 77% ± 2% (for low resistivity);
  • Wyoming Bentonite: 15% ± 1% (for moisture retention);
  • Sodium Sulphate: 8% ± 1% (for prevention of polarization).

The typical mixture has a resistivity of 45 ohm-cm when wet, and a compact density of 1.5 g/cm³.

Custom galvanic backfill mixture is available on request.

The galvanic backfill is utilized in prepackaged sacrificial Zinc and Magnesium anodes and is available in bulk supply in:

  • Supersacks of 2200/2400 lb (998/1089 Kg);
  • Bags of 50 lb (22.7 Kg), 56 bags/skid;
  • Custom packaging requirement.