Magnesium in Backfill

Magnesium in Backfill

Of all available anode material, magnesium is the one who has the highest driven voltage. Because of this, magnesium anodes are used advantageously in soil and water with high resistivity.

Normally there’s two different qualities being used, standard potential ( 1.5V ) and high potential (1.7V). When the anodes are intended for land installation, they are delivered as standard with a backfill mix of bentonite, as well as 5m long red XLPE/PVC 6mm2 cable.

The cable connection is embedded in epoxy.

Backfill: Plaster 75%, Bentonite 20%, Sodium sulfate 5%

Application:

Temporary cathodic protection systems:

The high current output of magnesium in seawater helps to achieve polarization rapidly. This solution is often used when the originally mounted zinc or aluminium systemsfail to provide enough current for polarization.
Temporary protection of land and other pipelines during construction and before the activisation of the impressed current system. The anodes are easily installed within the pipe trench as construction proceeds; additional excavation is not required.
De-scaling of tanks. The high potential and consequent hydrogen evolution at the cathode leads to rapid removal of surface scale.
External protection of ships' hulls whilst in fresh or brackish water. This often consists of anodes suspended over the vessels' sides.

Permanent cathodic protection systems:

Urban land pipes, where many small and individual cp systems are needed.
Service pipes to domestic and commercial premises. For small diameter and short length pipes, the current required is very low meaning that consumption rate of the anode will also be low.
Pipelines within river crossings. Often subdued to heavier corrosion.
External surfaces of buried storage tanks in aggressive environments
Internal surfaces of water storage tanks and treatment plants. The deposits are nontoxic and magnesium anodes may be used in potable water systems.
Additional protection in poorly protected areas for pipelines with impressed current CP systems, often due to coating damage.
The protection of short steel/iron pipe lengths or fittings (flanges, valves etc.) within non-metallic pipe systems. Some end users require the application of cathodic protection to all buried metallic plant.