Molybdates – Corrosion Inhibitor

Molybdenum chemicals are a specialty raw material that is widely used in the agricultural, lubricant, pigment & dye, and water treatment industries. In water treatment, sodium molybdate (Na2MoO4) has proven to be a superior corrosion inhibitor in open recirculating cooling systems and closed recirculating cooling systems. It is often applied at lower levels and in combination with other inhibitors, such as inorganic and organic phosphates. In addition to being a very effective inhibitor in both soft and hard water, molybdates are thermally stable and are also excellent passivators in the presence of oxygen. Furthermore, molybdate treatments are safer for the environment, and may be most appropriate where phosphate and/or zinc discharge is limited.

In industrial water treatment applications, sodium molybdate offers the best corrosion protection in systems of bimetallic construction versus sodium nitrite. In these mixed-metallurgy cooling systems, there is a high potential for galvanic corrosion. Sodium molybdate provides an advantage over using sodium nitrite because it is dosed at lower ppm(s), and this allows for lower conductivity of the circulating water. Because of the lower conductivity levels in the cooling water, the potential for galvanic corrosion is greatly decreased. (Sodium Molybdate at levels of 50 – 100 ppm offers the same level of corrosion inhibition that sodium nitrite does at levels of 800+ ppm.)

Sodium Molybdate Crystals
Sodium Molybdate Solution (35%)